Science.gov

Sample records for seyfert galaxies spitzer

  1. INFRARED SPECTRAL ENERGY DISTRIBUTIONS OF SEYFERT GALAXIES: SPITZER SPACE TELESCOPE OBSERVATIONS OF THE 12 {mu}m SAMPLE OF ACTIVE GALAXIES

    SciTech Connect

    Gallimore, J. F.; Yzaguirre, A.; Jakoboski, J.; Stevenosky, M. J.; Axon, D. J.; O'Dea, C. P.; Robinson, A.; Baum, S. A.; Buchanan, C. L.; Elitzur, M.; Elvis, M.

    2010-03-01

    The mid-infrared spectral energy distributions (SEDs) of 83 active galaxies, mostly Seyfert galaxies, selected from the extended 12 {mu}m sample are presented. The data were collected using all three instruments, Infrared Array Camera (IRAC), Infrared Spectrograph (IRS), and Multiband Imaging Photometer for Spitzer (MIPS), aboard the Spitzer Space Telescope. The IRS data were obtained in spectral mapping mode, and the photometric data from IRAC and IRS were extracted from matched, 20'' diameter circular apertures. The MIPS data were obtained in SED mode, providing very low-resolution spectroscopy (R {approx} 20) between {approx}55 and 90 {mu}m in a larger, 20'' x 30'' synthetic aperture. We further present the data from a spectral decomposition of the SEDs, including equivalent widths and fluxes of key emission lines; silicate 10 {mu}m and 18 {mu}m emission and absorption strengths; IRAC magnitudes; and mid-far-infrared spectral indices. Finally, we examine the SEDs averaged within optical classifications of activity. We find that the infrared SEDs of Seyfert 1s and Seyfert 2s with hidden broad line regions (HBLRs, as revealed by spectropolarimetry or other technique) are qualitatively similar, except that Seyfert 1s show silicate emission and HBLR Seyfert 2s show silicate absorption. The infrared SEDs of other classes within the 12 {mu}m sample, including Seyfert 1.8-1.9, non-HBLR Seyfert 2 (not yet shown to hide a type 1 nucleus), LINER, and H II galaxies, appear to be dominated by star formation, as evidenced by blue IRAC colors, strong polycyclic aromatic hydrocarbon emission, and strong far-infrared continuum emission, measured relative to mid-infrared continuum emission.

  2. CONTRIBUTION OF THE ACCRETION DISK, HOT CORONA, AND OBSCURING TORUS TO THE LUMINOSITY OF SEYFERT GALAXIES: INTEGRAL AND SPITZER OBSERVATIONS

    SciTech Connect

    Sazonov, S.; Churazov, E.; Krivonos, R.; Revnivtsev, M.; Sunyaev, R.; Vikhlinin, A.; Hickox, R. C.; Gorjian, V.; Werner, M. W.; Fabian, A. C.; Forman, W. R.

    2012-10-01

    We estimate the relative contributions of the supermassive black hole (SMBH) accretion disk, corona, and obscuring torus to the bolometric luminosity of Seyfert galaxies, using Spitzer mid-infrared (MIR) observations of a complete sample of 68 nearby active galactic nuclei (AGNs) from the INTEGRAL all-sky hard X-ray (HX) survey. This is the first HX-selected (above 15 keV) sample of AGNs with complementary high angular resolution, high signal-to-noise, MIR data. Correcting for the host galaxy contribution, we find a correlation between HX and MIR luminosities: L{sub 15{mu}m}{proportional_to}L{sup 0.74{+-}0.06}{sub HX}. Assuming that the observed MIR emission is radiation from an accretion disk reprocessed in a surrounding dusty torus that subtends a solid angle decreasing with increasing luminosity (as inferred from the declining fraction of obscured AGNs), the intrinsic disk luminosity, L{sub Disk}, is approximately proportional to the luminosity of the corona in the 2-300 keV energy band, L{sub Corona}, with the L{sub Disk}/L{sub Corona} ratio varying by a factor of 2.1 around a mean value of 1.6. This ratio is a factor of {approx}2 smaller than for typical quasars producing the cosmic X-ray background. Therefore, over three orders of magnitude in luminosity, HX radiation carries a large, and roughly comparable, fraction of the bolometric output of AGNs. We estimate the cumulative bolometric luminosity density of local AGNs at {approx}(1-3) Multiplication-Sign 10{sup 40} erg s{sup -1} Mpc{sup -3}. Finally, the Compton temperature ranges between kT{sub c} Almost-Equal-To 2 and Almost-Equal-To 6 keV for nearby AGNs, compared to kT{sub c} Almost-Equal-To 2 keV for typical quasars, confirming that radiative heating of interstellar gas can play an important role in regulating SMBH growth.

  3. Microvariability in Seyfert galaxies

    USGS Publications Warehouse

    Carini, M.T.; Noble, J.C.; Miller, H.R.

    2003-01-01

    We present the results of a search for microvariability in a sample of eight Seyfert galaxies. Microvariability (i.e., variations occurring on timescales of tens of minutes to hours) has been conclusively demonstrated to exist in the class of active galactic nuclei (AGNs) known as blazars. Its existence in other classes of AGNs is far less certain. We present the results of a study of eight Seyfert 1 galaxies, which were intensively monitored in order to determine whether such variations exist in these objects. Only one object, Ark 120, displayed any evidence of microvariations. The implications of these results with respect to current models of the mechanisms responsible for the observed emission in Seyfert galaxies are discussed. We compare our results with those obtained from other studies of microvariability in different classes of AGNs.

  4. Featured Image: Spitzer Galaxies

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-11-01

    These three galaxies (click for a full view!) were imaged as a part of the Spitzer Survey of Stellar Structure in Galaxies (S4G), a recent survey of 2352 nearby galaxies with deep imaging at 3.6 and 4.5 m. The bottom panels show false-color near-UV and far-UV images previously obtained with GALEX. The top panels show the new images obtained with Spitzer as part of S4G. The three galaxies shown here represent three types of galaxies that have a high concentration of mass in their centers, yet still have a high specific star-formation rate (the star formation rate per unit stellar mass):Barred galaxies with a prominent ring around their nucleus, like NGC 7552Interacting systems, like NGC 2782Galaxies with compact bulges and smooth extended disks, like NGC 3642To learn why this is the case, and to see more results from S4G, see the original paper below.CitationJuan Carlos Muoz-Mateos et al 2015 ApJS 219 3. doi:10.1088/0067-0049/219/1/3

  5. SEYFERT GALAXIES: NUCLEAR RADIO STRUCTURE AND UNIFICATION

    SciTech Connect

    Lal, Dharam V.; Shastri, Prajval; Gabuzda, Denise C.

    2011-04-10

    A radio study of a carefully selected sample of 20 Seyfert galaxies that are matched in orientation-independent parameters, which are measures of intrinsic active galactic nucleus power and host galaxy properties, is presented to test the predictions of the unified scheme hypothesis. Our sample sources have core flux densities greater than 8 mJy at 5 GHz on arcsec scales due to the feasibility requirements. These simultaneous parsec-scale and kiloparsec-scale radio observations reveal (1) that Seyfert 1 and Seyfert 2 galaxies have an equal tendency to show compact radio structures on milliarcsecond scales, (2) the distributions of parsec-scale and kiloparsec-scale radio luminosities are similar for both Seyfert 1 and Seyfert 2 galaxies, (3) there is no evidence for relativistic beaming in Seyfert galaxies, (4) similar distributions of source spectral indices in spite of the fact that Seyferts show nuclear radio flux density variations, and (5) the distributions of the projected linear size for Seyfert 1 and Seyfert 2 galaxies are not significantly different as would be expected in the unified scheme. The latter could be mainly due to a relatively large spread in the intrinsic sizes. We also find that a starburst alone cannot power these radio sources. Finally, an analysis of the kiloparsec-scale radio properties of the CfA Seyfert galaxy sample shows results consistent with the predictions of the unified scheme.

  6. A spectropolarimetric atlas of Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Smith, J. E.; Young, S.; Robinson, A.; Corbett, E. A.; Giannuzzo, M. E.; Axon, D. J.; Hough, J. H.

    2002-09-01

    We present optical spectropolarimetry of the nuclei of 36 Seyfert 1 galaxies, obtained with the William Herschel and the Anglo-Australian Telescopes from 1996 to 1999. In 20 of these, the optical emission from the active nucleus is intrinsically polarized. We have measured a significant level of polarization in a further seven objects but these may be heavily contaminated by Galactic interstellar polarization. The intrinsically polarized Seyfert 1 galaxies exhibit a variety of characteristics, with the average polarization ranging from <0.5 to 5 per cent and with many showing variations in both the degree and position angle of polarization across the broad Hα emission line. We identify a small group of Seyfert 1 galaxies that exhibit polarization properties similar to those of Seyfert 2 galaxies in which polarized broad lines have been discovered. These objects represent direct observational evidence that a Seyfert 2-like far-field polar scattering region is also present in Seyfert 1 galaxies. Several other objects have features that can be explained in terms of equatorial scattering of line emission from a rotating disc. We propose that much of the diversity in the polarization properties of Seyfert galaxies can be understood in terms of a model involving both equatorial and polar scattering, the relative importance of the two geometries as sources of polarized light being determined principally by the inclination of the system axis to the line of sight.

  7. Bright emission lines in new Seyfert galaxies

    SciTech Connect

    Afanasev, V.L.; Denisiuk, E.K.; Lipovetskii, V.A.; Shapovalova, A.I.

    1983-01-01

    Observational data are given on bright emission lines (H-alpha, H-beta, and forbidden N II, S II, and O III) for 14 recently discovered Seyfert galaxies. The investigated objects can be divided into three groups, which correspond approximately to the first (5 objects), the intermediate (4 objects), and the second (4 objects) Seyfert types. Attention is drawn to the properties of the galaxy Markaryan 1018, which has features of both the first and the second type and is distinguished by the weakness of its emission lines, which is probably due to a gas deficit. 7 references.

  8. Hα Imaging of Nearby Seyfert Host Galaxies

    NASA Astrophysics Data System (ADS)

    Theios, Rachel L.; Malkan, Matthew A.; Ross, Nathaniel R.

    2016-05-01

    We used narrowband (Δλ = 70 Å) interference filters with the CCD imaging camera on the Nickel 1.0 m telescope at Lick Observatory to observe 31 nearby (z < 0.03) Seyfert galaxies in the 12 μm active galaxy sample. We obtained pure emission-line images of each galaxy, which reach down to a flux limit of 7.3 × 10‑15 erg cm‑2 s‑1 arcsec‑2, and corrected these images for [N ii] emission and extinction. We separated the Hα emission line of the “nucleus” (central 100–1000 pc) from that of the host galaxy. The extended Hα emission is expected to be powered by newly formed hot stars, and indeed correlates well with other indicators of current star formation rates (SFRs) in these galaxies: extended 7.7 μm polycyclic aromatic hydrocarbon, total far-infrared, and radio luminosity. Relative to what would be expected from recent star formation, there is a 0.8 dex excess of radio emission in our Seyfert galaxies. The Hα luminosity we measured in the centers of our galaxies is dominated by the active galactic nucleus (AGN), and is linearly correlated with the hard X-ray luminosity. There is, however, an upward offset of 1 dex in this correlation for the Seyfert 1s, because their nuclear Hα emission includes a strong additional contribution from the broad-line region. We found a correlation between SFR and AGN luminosity. In spite of selection effects, we concluded that the absence of bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly significant. Finally, we used our measured spatial distributions of Hα emission to determine what these Seyfert galaxies would look like when observed through fixed apertures (e.g., a spectroscopic fiber) at high redshifts. We found that although all of these Seyfert galaxies would be detectable emission-line galaxies at any redshift, most of them would appear to be dominated by (>67%) their H ii region emission. Only the most luminous AGNs (log(L Hα /erg s‑1) > 41.5) would still be identified as

  9. Hα Imaging of Nearby Seyfert Host Galaxies

    NASA Astrophysics Data System (ADS)

    Theios, Rachel L.; Malkan, Matthew A.; Ross, Nathaniel R.

    2016-05-01

    We used narrowband (Δλ = 70 Å) interference filters with the CCD imaging camera on the Nickel 1.0 m telescope at Lick Observatory to observe 31 nearby (z < 0.03) Seyfert galaxies in the 12 μm active galaxy sample. We obtained pure emission-line images of each galaxy, which reach down to a flux limit of 7.3 × 10‑15 erg cm‑2 s‑1 arcsec‑2, and corrected these images for [N ii] emission and extinction. We separated the Hα emission line of the “nucleus” (central 100–1000 pc) from that of the host galaxy. The extended Hα emission is expected to be powered by newly formed hot stars, and indeed correlates well with other indicators of current star formation rates (SFRs) in these galaxies: extended 7.7 μm polycyclic aromatic hydrocarbon, total far-infrared, and radio luminosity. Relative to what would be expected from recent star formation, there is a 0.8 dex excess of radio emission in our Seyfert galaxies. The Hα luminosity we measured in the centers of our galaxies is dominated by the active galactic nucleus (AGN), and is linearly correlated with the hard X-ray luminosity. There is, however, an upward offset of 1 dex in this correlation for the Seyfert 1s, because their nuclear Hα emission includes a strong additional contribution from the broad-line region. We found a correlation between SFR and AGN luminosity. In spite of selection effects, we concluded that the absence of bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly significant. Finally, we used our measured spatial distributions of Hα emission to determine what these Seyfert galaxies would look like when observed through fixed apertures (e.g., a spectroscopic fiber) at high redshifts. We found that although all of these Seyfert galaxies would be detectable emission-line galaxies at any redshift, most of them would appear to be dominated by (>67%) their H ii region emission. Only the most luminous AGNs (log(L Hα /erg s‑1) > 41.5) would still be identified as

  10. A GMRT study of Seyfert galaxies NGC 4235 and NGC 4594: evidence of episodic activity?

    NASA Astrophysics Data System (ADS)

    Kharb, P.; Srivastava, S.; Singh, V.; Gallimore, J. F.; Ishwara-Chandra, C. H.; Ananda, Hota

    2016-06-01

    Low-frequency observations at 325 and 610 MHz have been carried out for two `radio-loud' Seyfert galaxies, NGC 4235 and NGC 4594 (Sombrero galaxy), using the Giant Meterwave Radio Telescope (GMRT). The 610 MHz total intensity and 325-610 MHz spectral index images of NGC 4235 tentatively suggest the presence of a `relic' radio lobe, most likely from a previous episode of active galactic nucleus (AGN) activity. This makes NGC 4235 only the second known Seyfert galaxy after Mrk 6 to show signatures of episodic activity. Spitzer and Herschel infrared spectral energy distribution (SED) modelling using the CLUMPYDREAM code predicts star formation rates (SFRs) that are an order of magnitude lower than those required to power the radio lobes in these Seyferts (˜0.13-0.23 M⊙ yr-1 compared to the required SFR of ˜2.0-2.7 M⊙ yr-1 in NGC 4594 and NGC 4235, respectively). This finding along with the detection of parsec and sub-kpc radio jets in both Seyfert galaxies, that are roughly along the same position angles as the radio lobes, strongly support the suggestion that Seyfert lobes are AGN powered. SED modelling supports the `true' type 2 classification of NGC 4594: this galaxy lacks significant dust obscuration as well as a prominent broad-line region. Between the two Seyfert galaxies, there is an inverse relation between their radio-loudness and Eddington ratio and a direct relation between their Eddington-scaled jet power and bolometric power.

  11. Spatially Resolved Infrared Spectroscopy of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Knop, Robert Andrew, Jr.

    This thesis presents infrared spectroscopy of the circumnuclear regions of 23 Seyfert galaxies. Observations are spectrally resolved with a resolution of λΔλ~1000 and spatially resolved to ~1'', corresponding to ~102 pc for the objects in the sample. The instrument used for the observations, the Palomar Near-Infrared Spectrometer, is described, and problems peculiar to reduction of data from it are discussed. The lines observed include Paβ, Brγ, (FeII) (λ=1.2567μm), and H2 (λ=2.1213μm). In nine objects, the coronal line (SIX) (λ=1.2524μm) is also detected. Spatially resolved line emission is clearly visible in approximately half of the objects observed. The data for five of the objects showing the best spatially resolved infrared line emission are analyzed in detail. These objects include Seyfert 1.5 galaxy NGC 4151 and Seyfert 2 galaxies Mk 1066, NGC 2110, NGC 4388, and Mk 3. The data for the remaining objects is presented in tabular form, and each object is discussed briefly. The data argue that processes associated with the Seyfert nucleus are responsible for the bulk of the observed (FeII) emission. Kinematic and spatial associations can be drawn between features in the (FeII) line profiles and other processes associated with the active nucleus, such as outflows seen in ionized optical emission and radio lobes. Most of the (FeII) appears to emerge from partially ionized regions excited by nuclear x-rays, with an additional contribution from fast shocks. Some of the H2 emission also appears to be associated with the nuclear activity. However, in some cases the H2 emission is observed to have a different spatial distribution from (FeII) and the H+ emission. The H2 emission is probably thermally excited. No significant differences are found between the infrared line emission of Seyfert and Seyfert 1.x galaxies.

  12. THE DIFFERENCE IN NARROW Fe K{alpha} LINE EMISSION BETWEEN SEYFERT 1 AND SEYFERT 2 GALAXIES

    SciTech Connect

    Liu Teng; Wang Junxian E-mail: jxw@ustc.edu.c

    2010-12-20

    We compile a sample of 89 Seyfert galaxies with both [O IV] 25.89 {mu}m line luminosities observed by Spitzer IRS and X-ray spectra observed by XMM-Newton EPIC. Using [O IV] emission as a proxy for active galactic nucleus (AGN) intrinsic luminosity, we find that although type 2 AGNs have higher line equivalent widths, the narrow Fe K{alpha} lines in Compton-thin and Compton-thick Seyfert 2 galaxies are 2.9{sup +0.8}{sub -0.6} and 5.6{sup +1.9}{sub -1.4} times weaker in terms of luminosity than Seyfert 1 galaxies, respectively. This indicates that different correction factors need to be applied for various types of AGNs before the narrow Fe K{alpha} line luminosity could serve as an intrinsic AGN luminosity indicator. We also find that Seyfert 1 galaxies in our sample have on average marginally larger line widths and higher line centroid energies, suggesting contamination from highly ionized Fe line or broader line emission from much smaller radius, but this effect is too weak to explain the large difference in narrow Fe K{alpha} line luminosity between type 1 and type 2 AGNs. This is the first observational evidence showing that the narrow Fe K{alpha} line emission in AGNs is anisotropic. The observed difference is consistent with theoretical calculations assuming a smoothly distributed obscuring torus and could provide independent constraints on the clumpiness of the torus.

  13. Infrared spectroscopy of starburst and Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Moorwood, A. F. M.; Oliva, E.

    1994-03-01

    We present and discuss some recent results ofgroundbased IR spectroscopie studies ofstarburst and Seyfert galaxies through the 1-5 μm atmospheric windows. Of particular interest in this spectral range are H and He recombination lines, stellar CO and other absorption bands which can provide information on the stellar populations; [SiVI, VII, IX], [CaVIII] and [SIX] coronal lines in Seyferts and [FeII] and ro-vibrational H2 lines from circumnuclear gas excited by high energy photons and winds associated with recently formed hot stars, SN/SNR and AGN. Recent progress in the latter case has largely been achieved through the first use of 2D arrays to obtain maps and images of the extended line emission in several relatively nearby galaxies.

  14. Narrow-Line Seyfert 1 Galaxies

    NASA Technical Reports Server (NTRS)

    Leighly, Karen M.

    2000-01-01

    The primary work during this year has been the analysis and interpretation of our HST spectra from two extreme Narrow-line Seyfert 1 galaxies (NLS1s) Infrared Astronomy Satellite (IRAS) 13224-3809 and 1H 0707-495. This work has been presented as an invited talk at the workshop entitled "Observational and theoretical progress in the Study of Narrow-line Seyfert 1 Galaxies" held in Bad Honnef, Germany December 8-11, as a contributed talk at the January 2000 AAS meeting in Atlanta, Georgia, and as a contributed talk at the workshop "Probing the Physics of Active Galactic Nuclei by Multiwavelength Monitoring" held at Goddard Space Flight Center June 20-22, 2000.

  15. The nuclear and integrated FIR emission of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    García-González, J.

    2015-09-01

    We present far-infrared (70-500micron) observations obtained with Herschel/PACS and SPIRE of 33 Seyfert galaxies from the Revised Shapley-Ames (RSA) catalogue. We selected these galaxies because they are nearby (median distance of 33Mpc) and have estimates of the nuclear and integrated star formation rates (SFR) from mid-infrared sub-arcsecond resolution and Spitzer/IRS spectroscopy, respectively. We measure the far-infrared nuclear (1kpc), 2kpc, and integrated spectral energy distributions (SEDs) from the Herschel images and estimate the unresolved nuclear emission at 70micron where Herschel provides the best angular resolution (median 0.9kpc). The goal is to select galaxies in our sample whose 70micron is mostly due to dust heated by the AGN. We will compare the 70micron emission together with existing nuclear 1-10micron SEDs and 8-13micron spectroscopy with clumpy torus model predictions. To estimate the AGN-produced 70micron emission we use a number of criteria. These include: (1) elevated nuclear 70/160 micron colours with respect to the typical colours of star forming galaxies, (2) 70micron excess emission with respect to the fit of the far-infrared SEDs with a grey body, (3) dust temperature higher than typical values of star forming galaxies, and (4) comparison of nuclear SFR obtained from 70 microns and mid-IR indicators.

  16. He I 10830 emission in Seyfert galaxies and QSOs

    NASA Technical Reports Server (NTRS)

    Levan, P. D.; Puetter, R. C.; Smith, H. E.; Rudy, R. J.

    1984-01-01

    He I line fluxes at 10830 A are reported for eight type-1 Seyfert galaxies, three QSOs and two type-2 Seyfert galaxies. The data are combined with He I line fluxes at 5876 A in order to obtain the ratio 10830/5876. The He I flux values resulting from this ratio are compared to fiducial values measured in gaseous nebulae. It is found that the values for gaseous nebulae are very similar to values observed in type-2 Seyfert galaxies, but are considerably larger than He I line flux values for type-1 Seyfert galaxies and QSOs. The data indicate the presence of high dust reddening and powerful optical depth effects in the type-2 Seyfert galaxies.

  17. The featureless continua and hydrogen lines of Seyfert 2 galaxies

    NASA Technical Reports Server (NTRS)

    Kinney, A. L.; Antonucci, R. R. J.; Ward, M. J.; Wilson, A. S.; Whittle, M.

    1991-01-01

    Optical and ultraviolet spectra taken in similar sized large apertures for 15 Seyfert 2 galaxies are presented. Measurements of emission-line strengths of Ly-alpha, H-alpha, and H-beta are used together with measurements of the ultraviolet slopes to estimate the ratio of recombination photons to ionizing photons. The photon ratios indicate that the ionizing continuum is being emitted anisotropically for at least six of the eight objects with UV slope measurements. The median value of the UV slope is indistinguishable from the UV slope of Seyfert 1 galaxies. This result suggests that in the occultation/reflection picture of Seyfert nuclei, the reflecting particles are free electrons and not dust. Previous observations of variability in Mrk 477 are verified, and it is shown that this galaxy exhibits characteristics of both Seyfert 1 and Seyfert 2 galaxies.

  18. Jet Directions in Seyfert Galaxies: Radio Continuum Imaging Data

    NASA Astrophysics Data System (ADS)

    Schmitt, H. R.; Ulvestad, J. S.; Antonucci, R. R. J.; Kinney, A. L.

    2001-02-01

    We present the results of VLA A-array 8.46 GHz continuum imaging of 55 Seyfert galaxies (19 Seyfert 1's and 36 Seyfert 2's). These galaxies are part of a larger sample of 88 Seyfert galaxies, selected from mostly isotropic properties, the flux at 60 μm, and warm infrared 25-60 μm colors. These images are used to study the structure of the radio continuum emission of these galaxies and their position angles, in the case of extended sources. These data, combined with information from broadband B and I observations, have been used to study the orientation of radio jets relative to the plane of their host galaxies (Kinney et al.).

  19. HNC, HCN and CN in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Pérez-Beaupuits, J. P.; Aalto, S.; Gerebro, H.

    2007-12-01

    Aims:Bright HNC 1-0 emission, rivalling that of HCN 1-0, has been found towards several Seyfert galaxies. This is unexpected since traditionally HNC is a tracer of cold (10 K) gas, and the molecular gas of luminous galaxies like Seyferts is thought to have bulk kinetic temperatures surpassing 50 K. There are four possible explanations for the bright HNC: (a) large masses of hidden cold gas; (b) chemistry dominated by ion-neutral reactions; (c) chemistry dominated by X-ray radiation; and (d) HNC enhanced through mid-IR pumping. In this work, we distinguish the cause of the bright HNC and to model the physical conditions of the HNC and HCN emitting gas. Methods: We have used SEST, JCMT and IRAM 30 m telescopes to observe HNC 3-2 and HCN 3-2 line emission in a selection of 5 HNC-luminous Seyfert galaxies. We estimate and discuss the excitation conditions of HCN and HNC in NGC 1068, NGC 3079, NGC 2623 and NGC 7469, based on the observed 3-2/1-0 line intensity ratios. We also observed CN 1-0 and 2-1 emission and discuss its role in photon and X-ray dominated regions. Results: HNC 3-2 was detected in 3 galaxies (NGC 3079, NGC 1068 and NGC 2623). Not detected in NGC 7469. HCN 3-2 was detected in NGC 3079, NGC 1068 and NGC 1365, it was not detected in NGC 2623. The HCN 3-2/1-0 ratio is lower than 0.3 only in NGC 3079, whereas the HNC 3-2/1-0 ratio is larger than 0.3 only in NGC 2623. The HCN/HNC 1-0 and 3-2 line ratios are larger than unity in all the galaxies. The HCN/HNC 3-2 line ratio is lower than unity only in NGC 2623, which makes it comparable to galaxies like Arp 220, Mrk 231 and NGC 4418. Conclusions: We conclude that in three of the galaxies the HNC emissions emerge from gas of densities n ⪉ 105 cm-3, where the chemistry is dominated by ion-neutral reactions. The line shapes observed in NGC 1365 and NGC 3079 show that these galaxies have no circumnuclear disk. In NGC 1068 the emission of HNC emerges from lower (<105 cm-3) density gas than HCN (>105 cm-3

  20. A statistical study of properties of Seyfert and starburst galaxies

    NASA Technical Reports Server (NTRS)

    Dahari, Oved; De Robertis, Michael M.

    1988-01-01

    Spectral and morphological data for 282 Seyfert and emission-line galaxies spanning radio to X-ray wavelengths are compiled. The data include a large number of optical emission-line measurements which have not been reported previously. These data are intended to provide a convenient summary of the relevant properties of these galaxies, as well as a data base to search for correlations among the various parameters in order to obtain a better understanding of the active galaxy phenomenon. The paper presents the data and analyzes the distributions of various properties of Seyfert 1 and Seyfert 2 galaxies and starburst galaxies. It is found that Seyferts 2s have a higher 60 micron/forbidden O III 5007 A flux ratio than Seyfert 1s. This result, combined with the fact that Seyfert 2s are more heavily reddened, indicate that they have a higher dust content. It is also found that starburst nuclei are comparable to Seyfert 2s in far-infrared and 20 cm luminosities, although their optical spectra are markedly different.

  1. The coronal parameters of local Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Marinucci, A.; Tortosa, A.; NuSTAR AGN Physics Working Group

    2016-05-01

    One of the open problems for AGN is the nature of the primary X-ray emission: It is likely due to Comptonization of soft UV photons, but the optical depth and temperature of the emitting corona were largely unknown before the launch of the Nuclear Spectroscopic Telescope Array (NuSTAR). It is the first focusing hard X-ray telescope on orbit, ∼ 100 times more sensitive in the 10-79 keV band compared to previous observatories, enabling the study of AGN at high energies with high precision. We present and discuss the results on the hot corona parameters of active galactic nuclei that have been recently measured with NuSTAR (often in coordination with XMM-Newton, Suzaku, or wift) with unprecedented accuracy, in a number of local Seyfert galaxies.

  2. Deficiency of ''Thin'' Stellar Bars in Seyfert Host Galaxies

    NASA Technical Reports Server (NTRS)

    Shlosman, Isaac; Peletier, Reynier F.; Knapen, Johan

    1999-01-01

    Using all available major samples of Seyfert galaxies and their corresponding control samples of closely matched non-active galaxies, we find that the bar ellipticities (or axial ratios) in Seyfert galaxies are systematically different from those in non-active galaxies. Overall, there is a deficiency of bars with large ellipticities (i.e., 'fat' or 'weak' bars) in Seyferts, compared to non-active galaxies. Accompanied with a large dispersion due to small number statistics, this effect is strictly speaking at the 2 sigma level. To obtain this result, the active galaxy samples of near-infrared surface photometry were matched to those of normal galaxies in type, host galaxy ellipticity, absolute magnitude, and, to some extent, in redshift. We discuss possible theoretical explanations of this phenomenon within the framework of galactic evolution, and, in particular, of radial gas redistribution in barred galaxies. Our conclusions provide further evidence that Seyfert hosts differ systematically from their non-active counterparts on scales of a few kpc.

  3. Multiwavelength tests of the dusty torus model for Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Mulchaey, John S.; Koratkar, Anuradha; Ward, Martin J.; Wilson, Andrew S.; Whittle, Mark; Antonucci, Robert R. J.; Kinney, Anne L.; Hurt, Todd

    1994-01-01

    We present a compilation of emission properties for a sample of 116 Seyfert galaxies based on both previously unpublished data and measurements available in the literature. These measurements include fluxes in the emission lines (O III) lambda(5007) and H-beta, as well as the infrared (25-60 microns), ultraviolet (1450 A), soft (0.2-4 keV), and hard (2-10 keV) X-ray continua. These are used to try to distinguish between isotropic and anisotropic emission properties of Seyfert galaxies. The distribution functions of (O III) lambda 5007 infrared, and hard X-ray continuum are similar for Seyfert 1's and Seyfert 2's, consistent with these properties being isotropic. The ultraviolet and soft X-ray continua of Seyfert 2's are underluminous relative to the type 1's suggesting photons at these energies escape from the central source anisotropically. There is a correlation between the ultraviolet continuum and emission-line fluxes in Seyfert 1's consistent with the idea that the central engine is responsible for powering the line emission. No such correlation is found for the Seyfert 2's. Instead, the scatter in the plot of ultraviolet continuum versus line emission suggests the true nuclear continuum luminosity is not seen at Earth in these objects. These properties are consistent with those expected in the dusty torus model.

  4. Spectrophotometry of Seyfert 2 galaxies and narrow-line radio galaxies

    NASA Technical Reports Server (NTRS)

    Koski, A. T.

    1978-01-01

    Results are reported for a spectrophotometric survey of several Seyfert 2 galaxies, intermediate Seyferts, and narrow-line radio galaxies. The emission-line spectra of the galaxies are analyzed, emphasizing line intensities, reddening, temperatures, densities, line strength correlations, line widths, and redshift differences. The continuous spectra are examined, and possible ionization sources are considered. It is found that: (1) there are no distinguishing differences between the spectra of Seyfert 2 galaxies and narrow-line radio galaxies; (2) the emission spectra are rich in lines from a wide range of ionization levels; (3) the continuum is starlight diluted by an underlying continuous spectrum; (4) the line widths of both classes of galaxies have the same distribution; (5) there appear to be regions of high and low ionization in the Seyfert 2 and narrow-line radio galaxies; (6) photoionization seems quite likely as the energy input to the gas; and (7) all the galaxies show a UV excess in their spectra.

  5. The Non-Stellar Infrared Continuum of Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Alonso-Herrero, Almudena; Quillen, Alice C.; Simpson, Chris; Efstathiou, Andreas; Ward, Martin J.

    2000-01-01

    JHKL'M (1 - 5 micrometers) imaging of a sample of Seyfert 2 galaxies is presented. We have performed an accurate estimate of the near-infrared non-stellar nuclear fluxes. We confirm that the near-infrared nuclear continuum between 1 and 2.2microns of some Seyfert 2s is dominated by stellar emission, whereas the continuum emission at longer wavelengths (lambda = 3 - 5 micrometers) is almost entirely non-stellar in origin. The non-stellar spectral energy distributions (SED) in the infrared (up to 15 micrometers) of Seyfert galaxies show a variety of shapes, and they are well reproduced with the tapered disk models of Efstathiou & Rowan-Robinson (1995). We have used two models, one including an optically thin cone component found to fit the SED of NGC 1068, and a coneless model. Although our modelling of the SEDs does not allow us to favor either model to account for all the observed SEDs, we find that the viewing angle towards the central source is well constrained by both models. The galaxies in our sample have fitted values of the viewing angle in the range Theta(sub V) = 0 deg - 64 deg, for the assumed model parameters. We have also investigated non-stellar color-color diagrams (L' - M vs. H - M and L' - M vs. H - L'). The colors of the Seyfert galaxies with viewing angles Theta(sub v) less than 30 deg are better reproduced with the cone model. These diagrams provide a good means to separate Seyfert 2s with moderate obscuration (A(sub V) approx. less than 20 mag from hard X-ray observations) from those with high obscuration. The ground-based 4.8 microns and ISO 9.6 microns luminosities are well correlated with the hard X-ray luminosities of Seyfert ls and 2s. These continuum emissions appear as a good indicator of the AGN luminosity, at least in the cases of hard X-ray Compton-thin Seyfert galaxies (N(sub H) less than or = 10(exp 24)/sq cm). We finally stress the finding that some Compton thick galaxies show bright non-stellar emission at 5 microns This suggests

  6. PSPC soft x-ray observations of Seyfert 2 galaxies

    NASA Technical Reports Server (NTRS)

    Turner, T. J.; Urry, C. M.; Mushotzky, R. F.

    1993-01-01

    We present the results from ROSAT PSPC soft x-ray (0.1-2.0 keV) observations of six Seyfert 2 galaxies, chosen from the brightest Seyfert 2s detected with the Einstein Imaging Proportional Counter. All of the targets were detected with the ROSAT PSPC. Spatial analysis shows that the source density within a few arcmin of each Seyfert 2 galaxy is a factor of approximately eight higher than in the rest of the inner field of view of the PSPC images. In NGC1365 it appears that the serendipitous sources may be x-ray binary systems in the host galaxy. The proximity of the serendipitous sources, typically within a few arcmin of the target Seyfert 2, means that previous x-ray observations of the Seyfert 2 galaxies have been significantly contaminated, and that source confusion is important on a spatial scale of approximately 1 arcmin. Some spectra, most notably Mrk3 and NGC1365, indicate the presence of a high equivalent width soft x-ray line blend consistent with unresolved iron L and oxygen K emission.

  7. Ultraviolet spectra of QSOs, BL Lacertae objects, and Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Lanzetta, Kenneth M.; Turnshek, David A.; Sandoval, Jennifer

    1993-01-01

    Motivated by the possibility of detecting strong absorption features toward extragalactic background objects, we present optimally extracted and co-added IUE spectra of QSOs, BL Lac objects, and Seyfert galaxies. These spectra together with those presented (in a similar work) by Kinney et al. form an essentially complete sample of the SWP, LWP, and LWR observations of QSOs, BL Lac objects, and Seyfert galaxies with redshifts z greater than 0.05 available in the IUE merged observation log as of 1991 December.

  8. Ultraviolet spectra of QSOs, BL Lacertae objects, and Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Lanzetta, Kenneth M.; Turnshek, David A.; Sandoval, Jennifer

    1993-02-01

    Motivated by the possibility of detecting strong absorption features toward extragalactic background objects, we present optimally extracted and co-added IUE spectra of QSOs, BL Lac objects, and Seyfert galaxies. These spectra together with those presented (in a similar work) by Kinney et al. form an essentially complete sample of the SWP, LWP, and LWR observations of QSOs, BL Lac objects, and Seyfert galaxies with redshifts z greater than 0.05 available in the IUE merged observation log as of 1991 December.

  9. The physical state of the obscuring torus in Seyfert galaxies

    SciTech Connect

    Krolik, J.H.; Lepp, S. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA )

    1989-12-01

    Calculations are presented describing the ionization, chemical, and thermal state of molecular material in the obscuring tori close to the nuclei of many Seyfert galaxies. These are unusual molecular clouds: their electron fractions are about .001 and their temperatures are about 1000 K. Cooling is accomplished primarily by radiation of NIR H2 lines and FIR CO lines. High-J (C-12)(O-16) rotational lines should eventually be detectable from the nearer Seyfert galaxies. Medium-J lines due to (C-13)(O-16) and (C-12)(O-18) as well as (C-12)(O-16) should also be strong. Because ordinary molecular clouds are weak in these lines, the nuclear CO emissions can be distinguished from CO emission farther out in the host galaxy's disk. 28 refs.

  10. Brackett alpha and gamma Observations of Starburst and Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Kawara, Kimiaki; Nishida, Minoru; Phillips, M. M.

    1989-02-01

    Br (Brackett) α and γ line fluxes of starburst and Seyfert galaxies are presented. The Bra line has been detected in seven of 12 galaxies. These data are combined with published Brackett line fluxes of M82 and NGC 253 to examine the relation between the extinction, A_v_, derived from the Brα/Brγ ratio and the optical depth, τ(10), of the silicate absorption at 10 microns. Generally speaking, a line of slope A_v_/τ(10) = 14 fits the data well, which is the same relation as found in the Milky Way. In the type 2 Seyferts NGC 1068 and NGC 5506, the observed Brα/Brγ ratios may not be simply explained by case B recombination with heavy extinction. The extinction values derived from Brα/Brγ are compared with those determined from optical and X-ray observations, and the implications are discussed.

  11. THE RELATIONSHIP BETWEEN BLACK HOLE GROWTH AND STAR FORMATION IN SEYFERT GALAXIES

    SciTech Connect

    Diamond-Stanic, Aleksandar M.; Rieke, George H.

    2012-02-20

    We present estimates of black hole accretion rates (BHARs) and nuclear, extended, and total star formation rates for a complete sample of Seyfert galaxies. Using data from the Spitzer Space Telescope, we measure the active galactic nucleus (AGN) luminosity using the [O IV] {lambda}25.89 {mu}m emission line and the star-forming luminosity using the 11.3 {mu}m aromatic feature and extended 24 {mu}m continuum emission. We find that black hole growth is strongly correlated with nuclear (r < 1 kpc) star formation, but only weakly correlated with extended (r > 1 kpc) star formation in the host galaxy. In particular, the nuclear star formation rate (SFR) traced by the 11.3 {mu}m aromatic feature follows a relationship with the BHAR of the form SFR{proportional_to} M-dot{sub BH}{sup 0.8}, with an observed scatter of 0.5 dex. This SFR-BHAR relationship persists when additional star formation in physically matched r = 1 kpc apertures is included, taking the form SFR{proportional_to} M-dot{sub BH}{sup 0.6}. However, the relationship becomes almost indiscernible when total SFRs are considered. This suggests a physical connection between the gas on sub-kiloparsec and sub-parsec scales in local Seyfert galaxies that is not related to external processes in the host galaxy. It also suggests that the observed scaling between star formation and black hole growth for samples of AGNs will depend on whether the star formation is dominated by a nuclear or an extended component. We estimate the integrated black hole and bulge growth that occurs in these galaxies and find that an AGN duty cycle of 5%-10% would maintain the ratio between black hole and bulge masses seen in the local universe.

  12. Discovery of Relativistic Outflow in the Seyfert Galaxy Ark 564

    NASA Astrophysics Data System (ADS)

    Gupta, A.; Mathur, S.; Krongold, Y.; Nicastro, F.

    2013-07-01

    We present Chandra High Energy Transmission Grating Spectra of the narrow-line Seyfert-1 galaxy Ark 564. The spectrum shows numerous absorption lines which are well modeled with low-velocity outflow components usually observed in Seyfert galaxies. There are, however, some residual absorption lines which are not accounted for by low-velocity outflows. Here, we present identifications of the strongest lines as Kα transitions of O VII (two lines) and O VI at outflow velocities of ~0.1c. These lines are detected at 6.9σ, 6.2σ, and 4.7σ, respectively, and cannot be due to chance statistical fluctuations. Photoionization models with ultra-high velocity components improve the spectral fit significantly, providing further support for the presence of relativistic outflow in this source. Without knowing the location of the absorber, its mass and energy outflow rates cannot be well constrained; we find \\dot{E}(outflow)/L_{bol} lower limit of >=0.006% assuming a bi-conical wind geometry. This is the first time that absorption lines with ultra-high velocities are unambiguously detected in the soft X-ray band. The presence of outflows with relativistic velocities in active galactic nuclei (AGNs) with Seyfert-type luminosities is hard to understand and provides valuable constraints to models of AGN outflows. Radiation pressure is unlikely to be the driving mechanism for such outflows and magnetohydrodynamic may be involved.

  13. A millimeter-wave survey of CO emission in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Heckman, T. M.; Blitz, L.; Wilson, A. S.; Armus, L.; Miley, G. K.

    1989-01-01

    Emission in the 115 GHz 1-0 line of CO has been detected in 18 Seyfert galaxies in a sample of 43. The CO properties of 29 Seyferts in the Revised Shapley Ames Catalog (RSA) are compared with the CO properties of normal galaxies of the same Hubble type. These RSA type 2 Seyferts have an average ratio of CO-to-blue luminosity that is about twice as large as that of the normal galaxies, but the RSA type 1 Seyferts have normal CO luminosities. The RSA type 2 Seyfert galaxies have an unusually large average ratio of CO luminosity-to-H I mass compared to normal disk galaxies. The RSA type 2 Seyferts have an average far-IR luminosity that is about four times larger than a non-Seyfert comparison sample, while the RSA type 1 Seyferts are not significantly more luminous than the non-Seyferts. The result imply that the two classes of Seyferts are intrinsically different from one another and that one class cannot evolve into another in less than a few million years.

  14. A millimeter-wave survey of CO emission in Seyfert galaxies

    SciTech Connect

    Heckman, T.M.; Blitz, L.; Wilson, A.S.; Armus, L.; Miley, G.K.; Leiden, Rijksuniversiteit, Sterrewacht )

    1989-07-01

    Emission in the 115 GHz 1-0 line of CO has been detected in 18 Seyfert galaxies in a sample of 43. The CO properties of 29 Seyferts in the Revised Shapley Ames Catalog (RSA) are compared with the CO properties of normal galaxies of the same Hubble type. These RSA type 2 Seyferts have an average ratio of CO-to-blue luminosity that is about twice as large as that of the normal galaxies, but the RSA type 1 Seyferts have normal CO luminosities. The RSA type 2 Seyfert galaxies have an unusually large average ratio of CO luminosity-to-H I mass compared to normal disk galaxies. The RSA type 2 Seyferts have an average far-IR luminosity that is about four times larger than a non-Seyfert comparison sample, while the RSA type 1 Seyferts are not significantly more luminous than the non-Seyferts. The result imply that the two classes of Seyferts are intrinsically different from one another and that one class cannot evolve into another in less than a few million years. 129 refs.

  15. Population Analysis of Seyfert Galaxies in the Coma Abell-1367 Supercluster

    NASA Astrophysics Data System (ADS)

    Jones, Megan; Wilcots, E. M.; Hess, K. M.

    2013-01-01

    In the hopes of finding a possible source of intergalactic heating, we are studying the population of active galaxies residing in and out of groups along the Coma-Abell 1367 supercluster to look at the occurrence of Seyfert galaxies. We report on the distribution of Seyfert galaxies as a function of environment across the supercluster and probe the characteristics of the population of groups that currently host at least one Seyfert. Of the 66 groups sampled, there are 11 groups containing one Seyfert and 6 groups containing multiple Seyferts, which leaves 49 groups without any activity. We have yet to determine whether the occurrence of Seyferts is dependent on environmental factors. So far, we have not identified a correlation between environment and AGN activity; activity occurs pretty evenly both within and outside of galaxy groups. However, there does seem to be some correlation between the size of the group and the the percentage of Seyfert activity; one group with over 250 members has a much smaller amount of Seyferts by percentage (9 Seyferts) than other groups with 10 or less members. We explore the effect of Seyfert activity on the intergalactic medium in galaxy groups.

  16. Constraining the Active Galactic Nucleus Contribution in a Multiwavelength Study of Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Melendez, M.; Kraemer, S.B.; Schmitt, H.R.; Crenshaw, D.M.; Deo, R.P.; Mushotzky, R.F.; Bruhweiler, F.C.

    2008-01-01

    We have studied the relationship between the high- and low-ionization [O IV] (lambda)25.89 microns, [Ne III] (lambda)15.56 microns, and [Ne II] (lambda)12.81 microns emission lines with the aim of constraining the active galactic nuclei (AGNs) and star formation contributions for a sample of 103 Seyfert galaxies.We use the [O IV] and [Ne II] emission as tracers for the AGN power and star formation to investigate the ionization state of the emission-line gas.We find that Seyfert 2 galaxies have, on average, lower [O IV]/[Ne II] ratios than Seyfert 1 galaxies. This result suggests two possible scenarios: (1) Seyfert 2 galaxies have intrinsically weaker AGNs, or (2) Seyfert 2 galaxies have relatively higher star formation rates than Seyfert 1 galaxies. We estimate the fraction of [Ne II] directly associated with the AGNs and find that Seyfert 2 galaxies have a larger contribution from star formation, by a factor of approx.1.5 on average, than what is found in Seyfert 1 galaxies. Using the stellar component of [Ne II] as a tracer of the current star formation, we found similar star formation rates in Seyfert 1 and Seyfert 2 galaxies.We examined the mid- and far-infrared continua and found that [Ne II] is well correlated with the continuum luminosity at 60 microns and that both [Ne III] and [O IV] are better correlated with the 25 micron luminosities than with the continuum at longer wavelengths, suggesting that the mid-infrared continuum luminosity is dominated by the AGN, while the far-infrared luminosity is dominated by star formation. Overall, these results test the unified model of AGNs and suggest that the differences between Seyfert galaxies cannot be solely due to viewing angle dependence.

  17. X-ray evidence of an obscured nucleus in the type 2 Seyfert galaxy Mkn3

    NASA Astrophysics Data System (ADS)

    Awaki, H.; Koyama, K.; Kunieda, H.; Tawara, Y.

    1990-08-01

    Seyfert galaxies are classified as type 1 or 2 according to the presence or absence of broad emission lines in the optical spectrum. The high velocities indicated by the broad lines in Seyfert 1 galaxies are taken to be good evidence of a compact, massive object, as are the strong and variable hard X-ray sources that are also generally observed in these objects. In contrast, Seyfert 2 galaxies possess neither of these characteristics, so the theory that they too have an accreting massive blackhole is less compelling. Since the discovery by spectropolarimetry of a 'hidden' Seyfert 1 nucleus in the prototypical Seyfert 2, NGC1068, the long-standing hope that the two classes may be unified has been revived. Here from observations by the Ginga satellite that another Seyfert 2, Mkn3, has the X-ray spectral signature of a hidden type 1 nucleus.

  18. From Spitzer Galaxy photometry to Tully-Fisher distances

    NASA Astrophysics Data System (ADS)

    Sorce, J. G.; Tully, R. B.; Courtois, H. M.; Jarrett, T. H.; Neill, J. D.; Shaya, E. J.

    2014-10-01

    This paper involves a data release of the observational campaign: Cosmicflows with Spitzer (CFS). Surface photometry of the 1270 galaxies constituting the survey is presented. An additional ˜400 galaxies from various other Spitzer surveys are also analysed. CFS complements the Spitzer Survey of Stellar Structure in Galaxies, that provides photometry for an additional 2352 galaxies, by extending observations to low galactic latitudes (|b| < 30°). Among these galaxies are calibrators, selected in the K band, of the Tully-Fisher relation. The addition of new calibrators demonstrates the robustness of the previously released calibration. Our estimate of the Hubble constant using supernova host galaxies is unchanged, H0 = 75.2 ± 3.3 km s-1 Mpc-1. Distance-derived radial peculiar velocities, for the 1935 galaxies with all the available parameters, will be incorporated into a new data release of the Cosmicflows project. The size of the previous catalogue will be increased by 20 per cent, including spatial regions close to the Zone of Avoidance.

  19. Environment of Seyfert 2 galaxies: the group of galaxies around NGC5252.

    NASA Astrophysics Data System (ADS)

    Freudling, W.; Prieto, M. Almudena

    1996-02-01

    The relatively large neutral hydrogen contents and enhanced density of companion galaxies around Seyfert 2 galaxies suggests that tidal interaction could play a major role in the evolution of Seyfert 2 galaxies. Recent observations of the distribution of neutral hydrogen in the active S0 galaxy NGC5252 have shown a disturbed morphology which suggests that the HI in this galaxy could have been acquired through interaction with neighboring galaxies (Prieto & Freudling 1993 and 1995). We have searched for other HI rich galaxies within a radius of 25 arcmin and a redshift range of +/-600km/s around the center location and redshift of NGC5252. A total of five galaxies were found, four of them are cataloged galaxies with no previous redshifts available. These five galaxies were mapped with the VLA in order to search for signs of recent tidal interactions. The maps and derived HI parameters are presented and compared to the one of NGC5252, the sixth member of the group. Two of the galaxies (UGC 8635) are an interacting pair. No signs of other recent interactions were found. Using the Arecibo telescope, we also searched for intergalactic neutral hydrogen between the group members as another potential source of gas for NGC5252. Upper limits on intergroup gas are given for three positions. The lack of evidence for interaction among the galaxies could be interpreted in two different ways. Either interaction occurred in the distant past and triggered activity in this galaxy over a long period of time. Alternatively, factors other than the gas supply might be responsible for the observation that Seyfert 2 galaxies tend to be surrounded by a region of enhanced galaxy density.

  20. Einstein SSS+MPC observations of Seyfert type galaxies

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; Turner, T. J.; Mushotzky, R. F.; Weaver, K.

    1989-01-01

    The X-ray spectra of 27 Seyfert galaxies measured with the Solid State Spectrometer (SSS) onboard the Einstein Observatory is investigated. This new investigation features the utilization of simultaneous data from the Monitor Proportional Counter (MPC) and automatic correction for systematic effects in the SSS. The new results are that the best-fit single power law indices agree with those previously reported, but that soft excesses are inferred for at least 20 percent of the measured spectra. The soft excesses are consistent with either an approximately 0.25 keV black body or Fe-L line emission.

  1. Einstein SSS+MPC observations of Seyfert type galaxies

    NASA Astrophysics Data System (ADS)

    Holt, S. S.; Turner, T. J.; Mushotzky, R. F.; Weaver, K.

    1989-11-01

    The X-ray spectra of 27 Seyfert galaxies measured with the Solid State Spectrometer (SSS) onboard the Einstein Observatory is investigated. This new investigation features the utilization of simultaneous data from the Monitor Proportional Counter (MPC) and automatic correction for systematic effects in the SSS. The new results are that the best-fit single power law indices agree with those previously reported, but that soft excesses are inferred for at least 20 percent of the measured spectra. The soft excesses are consistent with either an approximately 0.25 keV black body or Fe-L line emission.

  2. Detection of Ni 2 lambda 7378 in six Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Halpern, J. P.; Oke, J. B.

    1985-01-01

    A line due to Ni 2 7378 in the Seyfert galaxies NGC 1068, 2110, 3227, 4151, 5506, and Arp 102 B was detected. The average Ni abundance is about 2 times solar, which is 5 times less than in the filaments of the Crab Nebula. This argues for nucleosynthetic processing in the latter. The Ni 2 line is spatially revolved in NGC 1068, and shows at least a factor of 4 enhancement in the Ni abundance away from the nucleus. The off-nuclear abundance of Ni in NGC 1068 approaches that of the Crab, which strongly suggests that type supernovae enriched the off-nuclear gas clouds.

  3. Accretion tori and cones of ionizing radiation in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Acosta-Pulido, Jose A.; Perez-Fournon, Ismael; Calvani, Massimo; Wilson, Andrew S.

    1990-01-01

    The photoionization of extended narrow-line regions in Seyfert galaxies by the radiation produced in a thick accretion disk is studied. The emission-line spectrum is calculated for a range of black hole masses, varying the values of the ionization parameter and the disk size. It is found that models with a million solar masses fit observations of very large accretion disk sizes, while models with 10 million solar masses fit them better with smaller disks. The latter models are preferable since they have lower super-Eddington accretion rates.

  4. The Warm Absorber of the Seyfert Galaxy NGC 5548

    NASA Astrophysics Data System (ADS)

    Andrade, M.; Krongold, Y.; Elvis, M.; Nicastro, F.; Binette, L.; Brickhouse, N.

    2008-04-01

    We present a spectral analysis of the X-ray Chandraof the Seyfert 1 Galaxy NGC 5548. The warm absorber present in this object was modeled with the code PHASE. We detected two different outflow velocity systems in this source. One of the absorbing systems has outflow velocity of -1091+/-63 km s(-1) and the other of -568+/-49 km s(-1) . Each system required two absorption components with different ionization level to fit the observed features. Each velocity system may consist of a multi-phase medium.

  5. NEUTRAL GAS OUTFLOWS AND INFLOWS IN INFRARED-FAINT SEYFERT GALAXIES

    SciTech Connect

    Krug, Hannah B.; Veilleux, Sylvain; Rupke, David S. N. E-mail: veilleux@astro.umd.ed

    2010-01-10

    Previous studies of the Na I D interstellar absorption line doublet have shown that galactic winds occur in most galaxies with high infrared luminosities. However, in infrared-bright composite systems where a starburst coexists with an active galactic nucleus (AGN), it is unclear whether the starburst, the AGN, or both are driving the outflows. The present paper describes the results from a search for outflows in 35 infrared-faint Seyferts with 10{sup 9.9}< L{sub IR}/L{sub sun} < 10{sup 11}, or, equivalently, star formation rates (SFRs) of approx0.4-9 M{sub sun} yr{sup -1}, to attempt to isolate the source of the outflow. We find that the outflow detection rates for the infrared-faint Seyfert 1s (6%) and Seyfert 2s (18%) are lower than previously reported for infrared-luminous Seyfert 1s (50%) and Seyfert 2s (45%). The outflow kinematics of infrared-faint and infrared-bright Seyfert 2 galaxies resemble those of starburst galaxies, while the outflow velocities in Seyfert 1 galaxies are significantly larger. Taken together, these results suggest that the AGN does not play a significant role in driving the outflows in most infrared-faint and infrared-bright systems, except the high-velocity outflows seen in Seyfert 1 galaxies. Another striking result of this study is the high rate of detection of inflows in infrared-faint galaxies (39% of Seyfert 1s, 35% of Seyfert 2s), significantly larger than in infrared-luminous Seyferts (15%). This inflow may be contributing to the feeding of the AGN in these galaxies, and potentially provides more than enough material to power the observed nuclear activity over typical AGN lifetimes.

  6. A spectrophotometric atlas of Narrow-Line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Véron-Cetty, M.-P.; Véron, P.; Gonçalves, A. C.

    2001-06-01

    We have compiled a list of 83 objects classified as Narrow-Line Seyfert 1 galaxies (NLS1s) or known to have a broad Balmer component narrower than 2 000 km s-1. Of these, 19 turned out to have been spectroscopically misidentified in previous studies; only 64 of the selected objects are genuine NLS1s. We have spectroscopically observed 59 of them and tried to characterize their Narrow and Broad-Line Regions (NLR and BLR) by fitting the emission-lines with Gaussian and/or Lorentzian profiles. In most cases, the broad Balmer components are well fitted by a single Lorentzian profile, confirming previous claims that Lorentzian rather than Gaussian profiles are better suited to reproduce the shape of the NLS1s broad emission lines. This has consequences concerning their FWHMs and line ratios: when the broad Balmer components are fitted with a Lorentzian, most narrow line regions have line ratios typical of Seyfert 2s while, when a Gaussian profile is used for fitting the broad Balmer components, the line ratios are widely scattered in the usual diagnostic diagrams (Veilleux & Osterbrock \\cite{vei87}); moreover, the FWHM of the best fitting Lorentzian is systematically smaller than the FWHM of the Gaussian. We find that, in general, the [O III] lines have a relatively narrow Gaussian profile ( ~ 200-500 km s-1 FWHM) with often, in addition, a second broad ( ~ 500-1 800 km s-1 FWHM), blueshifted Gaussian component. We do not confirm that the [O III] lines are weak in NLS1s. As previously suggested, there is a continuous transition of all properties between NLS1s and classical Broad-Line Seyfert 1 Galaxies (BLS1s) and the limit of 2000 km s-1 used to separate the two species is arbitrary; R4570, the ratio of the Fe II to the Hβ fluxes, could be a physically more meaningful parameter to distinguish them.

  7. INDECENT EXPOSURE IN SEYFERT 2 GALAXIES: A CLOSE LOOK

    SciTech Connect

    Tran, Hien D.; Lyke, J. E.; Mader, Jeff A.

    2011-01-10

    NGC 3147, NGC 4698, and 1ES 1927+654 are active galaxies that are classified as Seyfert 2s, based on the line ratios of strong narrow emission lines in their optical spectra. However, they exhibit rapid X-ray spectral variability and/or little indication of obscuration in X-ray spectral fitting, contrary to expectation from the active galactic nucleus (AGN) unification model. Using optical spectropolarimetry with LRIS and near-infrared spectroscopy with NIRSPEC at the W. M. Keck Observatory, we conducted a deep search for hidden polarized broad H{alpha} and direct broad Pa{beta} or Br{gamma} emission lines in these objects. We found no evidence for any broad emission lines from the active nuclei of these galaxies, suggesting that they are unobscured, completely 'naked' AGNs that intrinsically lack broad-line regions.

  8. Mid-J CO Emission in Nearby Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Pereira-Santaella, Miguel; Spinoglio, Luigi; Busquet, Gemma; Glenn, Jason; Isaak, Kate; Kamenetzky, Julia; Rangwala, Naseem; Schirm, Maximilien R. P.; Baes, Maarten; Barlow, Michael J.; Boselli, Alessandro; Cooray, Asantha; Cormier, Diane

    2012-12-01

    We study for the first time the complete sub-millimeter spectra (450 GHz to 1550 GHz) of a sample of nearby active galaxies observed with the SPIRE Fourier Transform Spectrometer (SPIRE/FTS) onboard Herschel. The CO ladder (from Jup = 4 to 12) is the most prominent spectral feature in this range. These CO lines probe warm molecular gas that can be heated by ultraviolet photons, shocks, or X-rays originated in the active galactic nucleus or in young star-forming regions. In these proceedings we investigate the physical origin of the CO emission using the averaged CO spectral line energy distribution (SLED) of six Seyfert galaxies. We use a radiative transfer model assuming an isothermal homogeneous medium to estimate the molecular gas conditions. We also compare this CO SLED with the predictions of photon and X-ray dominated region (PDR and XDR) models.

  9. Observational effects of interaction in the Seyfert galaxy NGC 7469

    NASA Technical Reports Server (NTRS)

    Pronik, I. I.; Metik, L.

    1990-01-01

    Some pecularities of the circummucleus of the Seyfert galaxy NGC 7469 were revealed, plausibly caused by interaction with the satellite IC 5283 and a starlike detail, situated on the edge of the west spiral branch 14 seconds from the nucleus. Shock excited H II regions were noted in the part of NGC 7469 turned toward the satellite IC 5283. The galaxy's central radio structure (lambda approx. 6 cm) stretches in the direction toward the satellite IC 5283 and the starlike detail. The spectum and color index of the starlike detail suggest that it is a cluster of early type stars (M sub V = -19 sup m) and dust clouds (A sub V = 3 sup m), in NGC 7469.

  10. Spitzer and JCMT Observations of the Active Galactic Nucleus in the Sombrero Galaxy (NGC 4594)

    NASA Astrophysics Data System (ADS)

    Bendo, George J.; Buckalew, Brent A.; Dale, Daniel A.; Draine, Bruce T.; Joseph, Robert D.; Kennicutt, Robert C., Jr.; Sheth, Kartik; Smith, John-David T.; Walter, Fabian; Calzetti, Daniela; Cannon, John M.; Engelbracht, Charles W.; Gordon, Karl D.; Helou, George; Hollenbach, David; Murphy, Eric J.; Roussel, Hélène

    2006-07-01

    We present Spitzer 3.6-160 μm images, Spitzer mid-infrared spectra, and JCMT SCUBA 850 μm images of the Sombrero Galaxy (NGC 4594), an Sa galaxy with a 109 Msolar low-luminosity active galactic nucleus (AGN). The brightest infrared sources in the galaxy are the nucleus and the dust ring. The spectral energy distribution of the AGN demonstrates that, while the environment around the AGN is a prominent source of mid-infrared emission, it is a relatively weak source of far-infrared emission, as had been inferred for AGNs in previous research. The weak nuclear 160 μm emission and the negligible polycyclic aromatic hydrocarbon emission from the nucleus also implies that the nucleus is a site of only weak star formation activity and the nucleus contains relatively little cool interstellar gas needed to fuel such activity. We propose that this galaxy may be representative of a subset of low-ionization nuclear emission region galaxies that are in a quiescent AGN phase because of the lack of gas needed to fuel circumnuclear star formation and Seyfert-like AGN activity. Surprisingly, the AGN is the predominant source of 850 μm emission. We examine the possible emission mechanisms that could give rise to the 850 μm emission and find that neither thermal dust emission, CO line emission, bremsstrahlung emission, nor the synchrotron emission observed at radio wavelengths can adequately explain the measured 850 μm flux density by themselves. The remaining possibilities for the source of the 850 μm emission include a combination of known emission mechanisms, synchrotron emission that is self-absorbed at wavelengths longer than 850 μm, or unidentified spectral lines in the 850 μm band.

  11. Near-Infrared Coronal Lines in Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Portilla, J. G.; Tejeiro, J. M.; Rodríguez-Ardila, A.

    2006-06-01

    Seyfert galaxies show in their spectra coronal lines (CLs). Researchers have proposed a physical region responsible of the emission of CLs named Coronal Line Region (CLR). Some authors have suggested that CLR is well extended to the NLR; others propose its location between the BLR and NLR while others suggest that CLR is situated in the inner face of the obscuring torus. The goal of this work is contribute to the discussion about the location of the CLR. Our hypothesis is that they are emitted in the inner walls of the torus. Spectral analysis of a sample of Seyfert 1 (Sy1) and Seyfert 2 (Sy2) galaxies can give insights about the location of the CLR. We took NIR spectra of the five Sy1 and five Sy2 galaxies. Those spectra were taken in at the NASA 3-m IRTF using the SpeX spectrome-ter. CLs are observed in all the objects of the sample. [Si VI] λ1.963 μm, is present in all of them; [S VIII] λ0.991 μm, is also present (except in H1143-182 and Mrk 1066); it is frequent to observe too [S IX] λ1.252 μm, and [Si X] λ1.430 μm. [Si VI] λ1.963 μm is observed in both types of galaxies. Values for FWHM, assuming Gaussian profiles, for the [Si VI] λ1.963 μm range from 250 to 530 km/s whilst those for S [IX] λ1.252 μm and [Si X] λ1.43 μm tend to be higher: 300 to 1150 and 260 to 1320 km/s, respectively. This seems to suggest that, for CL, those species with higher ionization potential present higher bulk velocity of the emitting clouds and therefore are situated nearer to the central mass concentration. The apparent fact that CL from species of higher ionization potential (χ) are preferentially observed in Sy1 rather than Sy2 seems to be coherent with the existence of a obscuring torus required by unified models for an active galactic nucleus (AGN): the Sy1 type shows internal regions of the AGN, including the BLR and internal parts of the torus. It is feasible then, that some of the high-χ coronal emission (i.e. [Si X]) are produced in the inner wall of the

  12. Nebular Line Emission in z 1 Spitzer Infrared-Luminous Galaxies

    NASA Astrophysics Data System (ADS)

    Krause, John; Papovich, C.; Finkelstein, S.; Willmer, C.; Egami, E.; Conselice, C.; Huang, J.; Koo, D.; Laird, E.; Le Floc'h, E.; Lotz, J.; Maia, M.; Marcillac, D.; Nandra, K.; Webb, T.; Weiner, B.

    2010-01-01

    We present near-infrared (IR) spectroscopic observations from the Multi-Object IR Camera and Spectrograph (MOIRCS) on the Subaru telescope of a sample of 21 IR-luminous galaxies in the approximate range 1 < z < 1.5. These galaxies were selected based on their Spitzer 24-micron flux densities (S(24 micron) > 0.1 mJy) and known spectroscopic redshifts from the All-Wavelength Extended Groth Strip International Survey (AEGIS). We measure rest-frame optical emission line fluxes for H-alpha and [NII], and also [OIII] and H-beta, where available. We use emission-line diagnostics to constrain the origin of the ionization in these objects: processes associated with star formation or AGN (including Seyferts and LINERs). The high-redshift galaxies in our sample have similar [NII] / H-alpha flux ratios compared to low-redshift (z 0.1) IR-luminous galaxies (Kim et al., 1995; Veilleux et al., 1995) for galaxies with implied IR luminosities of 11 < Log L(8-1000 micron) / L sol < 12. However, we find evidence that the IR-luminous galaxies in our sample with implied Log L(8-1000 micron) / L sol > 12 have lower [NII] / H-alpha ratios than low-redshift galaxies with comparable IR luminosity, implying the higher redshift IR-luminous galaxies may have a higher fraction of systems dominated by star formation. We also study the relation of our rest-frame optical emission-line diagnostics to other indicators of AGN activity, including the mid-IR colors and X-ray luminosities. In addition, we compare star-formation-rate indicators from our dust-corrected H-alpha emission line luminosities to those from the mid-to-far IR and compare these as a function of IR luminosity against the low-redshift sample.

  13. INVESTIGATING THE CORE MORPHOLOGY-SEYFERT CLASS RELATIONSHIP WITH HUBBLE SPACE TELESCOPE ARCHIVAL IMAGES OF LOCAL SEYFERT GALAXIES

    SciTech Connect

    Rutkowski, M. J.; Hegel, P. R.; Kim, Hwihyun; Windhorst, R. A.; Tamura, Kazuyuki

    2013-07-01

    The unified model of active galactic nuclei (AGNs) has provided a successful explanation for the observed diversity of AGNs in the local universe. However, recent analysis of multi-wavelength spectral and image data suggests that the unified model is only a partial theory of AGNs, and may need to be augmented to remain consistent with all observations. Recent studies using high spatial resolution ground- and space-based observations of local AGNs show that Seyfert class and the ''core'' (r {approx}< 1 kpc) host-galaxy morphology are correlated. Currently, this relationship has only been established qualitatively, by visual inspection of the core morphologies of low-redshift (z < 0.035) Seyfert host galaxies. We re-establish this empirical relationship in Hubble Space Telescope optical imaging by visual inspection of a catalog of 85 local (D < 63 Mpc) Seyfert galaxies. We also attempt to re-establish the core morphology-Seyfert class relationship using an automated, non-parametric technique that combines both existing classification parameter methods (the adapted CAS and G-M {sub 20}) and a new method which implements the Source Extractor software for feature detection in unsharp-mask images. This new method is designed explicitly to detect dust features in the images. We use our automated approach to classify the morphology of the AGN cores and determine that Sy2 galaxies visually appear, on average, to have more dust features than Sy1. With the exception of this ''dustiness'' however, we do not measure a strong correlation between the dust morphology and the Seyfert class of the host galaxy using quantitative techniques. We discuss the implications of these results in the context of the unified model.

  14. Is the cluster environment quenching the Seyfert activity in elliptical and spiral galaxies?

    NASA Astrophysics Data System (ADS)

    de Souza, R. S.; Dantas, M. L. L.; Krone-Martins, A.; Cameron, E.; Coelho, P.; Hattab, M. W.; de Val-Borro, M.; Hilbe, J. M.; Elliott, J.; Hagen, A.; COIN Collaboration

    2016-09-01

    We developed a hierarchical Bayesian model (HBM) to investigate how the presence of Seyfert activity relates to their environment, herein represented by the galaxy cluster mass, M200, and the normalized cluster centric distance, r/r200. We achieved this by constructing an unbiased sample of galaxies from the Sloan Digital Sky Survey, with morphological classifications provided by the Galaxy Zoo Project. A propensity score matching approach is introduced to control the effects of confounding variables: stellar mass, galaxy colour, and star formation rate. The connection between Seyfert-activity and environmental properties in the de-biased sample is modelled within an HBM framework using the so-called logistic regression technique, suitable for the analysis of binary data (e.g. whether or not a galaxy hosts an AGN). Unlike standard ordinary least square fitting methods, our methodology naturally allows modelling the probability of Seyfert-AGN activity in galaxies on their natural scale, i.e. as a binary variable. Furthermore, we demonstrate how an HBM can incorporate information of each particular galaxy morphological type in an unified framework. In elliptical galaxies our analysis indicates a strong correlation of Seyfert-AGN activity with r/r200, and a weaker correlation with the mass of the host cluster. In spiral galaxies these trends do not appear, suggesting that the link between Seyfert activity and the properties of spiral galaxies are independent of the environment.

  15. Ultraviolet and optical spectra of high-ionization Seyfert galaxies with narrow lines

    NASA Technical Reports Server (NTRS)

    Crenshaw, D. Michael; Peterson, Bradley M.; Korista, Kirk T.; Wagner, R. Mark; Aufdenberg, Jason P.

    1991-01-01

    Ultraviolet and optical spectra are presented for three unusual Seyfert galaxies (Mrk 1239, Mrk 42, and Mrk 493) that resemble Seyfert 1 galaxies in that they have strong high-ionization lines and strong nonstellar continua, but resemble Seyfert 2 galaxies in that the widths of their permitted lines are as narrow as the widths of their forbidden lines. The He II lambda 1640 and He II lambda 4686 lines are used to determine an upper limit to the reddening experienced by the emission lines. Published optical data show that these particular high-ionization narrow-line (HINL) Seyferts have low lambda 5007 H beta ratios and strong Fe II emission, which suggest the presence of high-density regions. The low Lalpha/H-beta ratios in these objects indicate that high-density clouds are indeed present, and, like the broad-line region clouds in Seyfert 1 galaxies, these clouds have large optical depths with partially ionized zones. Overall, the line ratios and continuum fluxes of these particular HINL Seyferts are indistinguishable from those of broad-lined Seyfert 1 galaxies.

  16. Radio structures of Seyfert galaxies. VII - Extension of a distance-limited sample

    NASA Technical Reports Server (NTRS)

    Ulvestad, James S.; Wilson, Andrew S.

    1989-01-01

    The VLA has been used at 6 and 20 cm to observe 27 Seyfert galaxies with recessional velocities less than 4600 km/s that had not been mapped previously. The sample shows weak trends for Seyfert 2 galaxies to have more luminous and larger radio sources than Seyfert 1 galaxies. A 20 cm radio luminosity function is constructed for each Seyfert type and shown to be fairly flat for powers betwen 10 to the 20th and 10 to the 23rd W/Hz. About 10 percent of the galaxies in the present sample may have flat-spectrum components contributing a substantial amount of their total flux density at centimeter wavelengths.

  17. Far-infrared properties of optically-selected quasars and Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Edelson, R. A.; Malkan, M. A.

    1987-01-01

    Pointed IRAS observations and ground based observations are used to determine the infrared properties of optically selected galaxies and quasars. The use of complete, unbiased, optically selected samples means that statistical tests can be applied to probe the underlying properties of active galactic nuclei (AGNs). The near infrared to millimeter spectral energy distributions (SEDs) were studied of the CfA Seyfert galaxies, a well defined, unbiased sample of 25 Type 1 and 23 Type 2 Seyfert galaxies selected by optical spectroscopy. Data given show strong trends in the infrared SEDs. Strong evidence is also given that the infrared spectra of Seyfert 2 galaxies are dominated by thermal emission from warm dust, while nonthermal emission is more important in the spectra of quasars and luminous Seyfert 1 nuclei.

  18. Extinction, profile asymmetry, and tidal effects in Seyfert and starburst galaxies

    NASA Technical Reports Server (NTRS)

    Dahari, Oved; De Robertis, Michael M.

    1988-01-01

    Possible correlations between luminosity, extinction, and morphological properties of 246 Seyfert and starburst galaxies are investigated. It is shown that the asymmetry of the forbidden O III 5007 A profile is correlated with the signature of dust in both Seyfert types, and therefore establishes a direct connection between them. A positive correlation is found between soft X-ray luminosities and optical reddening for Seyfert 2's and a negative correlation for Seyfert 1's. These and other correlations are discussed in the context of current models of active nuclei. No statistically significant differences are found between Seyferts with and without companions, except that interacting Seyfert 2's have excess infrared and radio-continuum emission.

  19. Reverberation mapping of the Seyfert 1 galaxy NGC 7469

    SciTech Connect

    Peterson, B. M.; Grier, C. J.; Pogge, R. W.; De Rosa, G.; Denney, K. D.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C.; Horne, Keith; Bentz, M. C.; Sergeev, S. G.; Borman, G. A.; Minezaki, T.; Siverd, R. J.; Bord, D. J.; and others

    2014-11-10

    A large reverberation-mapping study of the Seyfert 1 galaxy NGC 7469 has yielded emission-line lags for Hβ λ4861 and He II λ4686 and a central black hole mass measurement M {sub BH} ≈ 1 × 10{sup 7} M {sub ☉}, consistent with previous measurements. A very low level of variability during the monitoring campaign precluded meeting our original goal of recovering velocity-delay maps from the data, but with the new Hβ measurement, NGC 7469 is no longer an outlier in the relationship between the size of the Hβ-emitting broad-line region and the luminosity of the active galactic nucleus. It was necessary to detrend the continuum and Hβ and He II λ4686 line light curves and those from archival UV data for different time-series analysis methods to yield consistent results.

  20. Line asymmetry in the Seyfert Galaxy NGC 3783

    NASA Technical Reports Server (NTRS)

    Ramirez, J. M.; Bautista, Manuel; Kallman, Timothy

    2005-01-01

    We have reanalyzed the 900 ks Chandra X-ray spectrum of NGC 3783, finding evidence on the asymmetry of the spectral absorption lines. The lines are fitted with a parametric expression that results from an analytical treatment of radiatively driven winds. The line asymmetry distribution derived from the spectrum is consistent with a non-spherical outflow with a finite optical depth. Within this scenario, our model explains the observed correlations between the line velocity shifts and the ionization parameter and between the line velocity shift and the line asymmetry. The present results may provide a framework for detailed testing of models for the dynamic and physical properties of warm absorber in Seyfert galaxies.

  1. STIS UV Observations of the Seyfert 1 Galaxy Mrk 766

    NASA Astrophysics Data System (ADS)

    Kaiser, M. E.; Reynolds, C. S.; Wilms, J.

    2002-12-01

    We present ultraviolet spectra of the z=0.0129 Narrow Line Seyfert 1 galaxy Mrk 766. For wavelengths extending from ~1150-3100 Å we have obtained low spectral resolution, ~1-2 Å, observations with HST/STIS. Our STIS spectrum of Mrk 766 exhibits emission from Lyman α , NV λ 1240, CIVλ 1549, CIII]λ 1909, and MgII λ 2800. We will present results for fits to an intrinsic absorber and discuss our results in the context of the standard warm absorber model and an alternative model presented by Branduardi-Raymont et al. (2001) for the XMM-Newton X-ray observations along this line of sight. Support for these observations was provided by contract NAS5-30403.

  2. NICMOS POLARIMETRY OF 'POLAR-SCATTERED' SEYFERT 1 GALAXIES

    SciTech Connect

    Batcheldor, D.; Robinson, A.; Axon, D. J.; Young, S.; Quinn, S.; Smith, J. E.; Hough, J.; Alexander, D. M.

    2011-09-01

    The nuclei of Seyfert 1 galaxies exhibit a range of optical polarization characteristics that can be understood in terms of two scattering regions producing orthogonal polarizations: an extended polar scattering region (PSR) and a compact equatorial scattering region (ESR), located within the circum-nuclear torus. Here we present NICMOS 2.0 {mu}m imaging polarimetry of six 'polar-scattered' Seyfert 1 (S1) galaxies, in which the PSR dominates the optical polarization. The unresolved nucleus (<0.''58) is significantly polarized in only three objects, but five of the six exhibit polarization in a 0.''58-1.''5 circum-nuclear annulus. In Fairall 51 and ESO 323-G077, the polarization position angle at 2 {mu}m ({theta}{sub 2}{sub {mu}m}) is consistent with the average for the optical spectrum ({theta}{sub v}), implying that the nuclear polarization is dominated by polar scattering at both wavelengths. The same is probably true for NGC 3227. In both NGC 4593 and Mrk 766, there is a large difference between {theta}{sub 2}{sub {mu}m} and {theta}{sub v} off-nucleus, where polar scattering is expected to dominate. This may be due to contamination by interstellar polarization in NGC 4593, but there is no clear explanation in the case of the strongly polarized Mrk 766. Lastly, in Mrk 1239, a large change ({approx}60{sup 0}) in {theta}{sub 2}{sub {mu}m} between the nucleus and the annulus indicates that the unresolved nucleus and its immediate surroundings have different polarization states at 2 {mu}m, which we attribute to the ESR and PSR, respectively. A further implication is that the source of the scattered 2 {mu}m emission in the unresolved nucleus is the accretion disk, rather than torus hot dust emission.

  3. Spitzer Space Telescope's View of Galaxy Messier 101

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for larger version

    The galaxy Messier 101 is a swirling spiral of stars, gas, and dust. Messier 101 is nearly twice as wide as our Milky Way galaxy. Spitzer's view, taken in infrared light, reveals the galaxy's delicate dust lanes as yellow-green filaments. Such dense dust clouds are where new stars can form. In this image, dust warmed by the light of hot, young stars glows red. The rest of the galaxy's hundreds of billions of stars are less prominent and form a blue haze. Astronomers can use infrared light to examine the dust clouds where stars are born.

  4. Erratum: A Comparison of Radio Axis with Host Galaxy Plane Axis in Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Schmitt, Henrique R.; Kinney, Anne L.; Storchi-Bergmann, Thaisa; Antonucci, Robert

    1997-08-01

    In the paper ``A Comparison of Radio Axis with Host Galaxy Plane Axis in Seyfert Galaxies'' by Henrique R. Schmitt, Anne L. Kinney, Thaisa Storchi-Bergmann, & Robert Antonucci (ApJ, 477, 623 [1997]), there are errors in Table 1 and Figure 6, and there is a reference to a previous work that should be stated. With respect to the latter, the authors compare the position angle of small-scale radio structures in Seyfert galaxies with the position angle of their host galaxy major axis. In their analysis they find a zone of avoidance, where the small-scale radio axis avoids close alignment with the host galaxy minor axis. The authors wish to note that J. S. Ulvestad and A. S. Wilson (ApJ, 285, 439 [1984]) already observed a paucity of radio structures aligned with the host galaxy minor axis in Seyfert 2 galaxies, although on a smaller sample. Ulvestad & Wilson was referenced in their paper as Ulvestad & Wilson (1984b). In Table 1 there were errors in the references listed in the note to the table. A new version of Table 1 with correct references is given here, and the following reference entries should be added to the reference list of the original paper: Mulchaey, J. S., Wilson, A. S., & Tsvetanov, Z. I. 1996, ApJS, 102, 309; Oke, J. B., & Lauer, T. R. 1979, ApJ, 230, 360; Simkin, S. M. 1975, ApJ, 200, 567. Figure 6a was printed twice, once correctly and once incorrectly in place of Figure 6c. The correct version of Figure 6c appears below.

  5. Observational model of the ionized gas in Seyfert and radio-galaxy nuclei*

    PubMed Central

    Osterbrock, Donald E.

    1978-01-01

    Equivalent widths of the total emission-line Hβ in Seyfert 1, Seyfert 2, and intermediate-type Seyfert galaxies, expressed in terms of the featureless continuum, all have approximately the same frequency distribution. This suggests that the energy-input mechanism to both the narrow-line, low-density gas and the broad-line, high-density gas is photoionization by the featureless continuum. The reason for the weakness of the narrow emission lines in extreme Seyfert 1 galaxies is then the absorption of most of the ionizing photons in the dense gas near the central source. The statistics of line widths can be fitted by a model in which the dense gas has typical rotational velocity 5000 km/sec and typical turbulent velocity 2000 km/sec. A model is proposed in which the dense gas forms a rotating, turbulent disk with dimension ≈0.1 pc and height/diameter ≈2/5. Seyfert 2 galaxies are objects with little dense gas, and intermediate-type Seyfert galaxies are objects in which the dense gas is optically thin to ionizing radiation at least along the poles. Most radio galaxies have strong narrow emission lines, suggesting that escape of radio plasma can only occur where some ionizing photons can also escape from the dense gas. Other predictions, implications, and tests of this model are discussed. Images PMID:16592488

  6. Variable Iron K(alpha) Lines in Seyfert 1 Galaxies

    NASA Technical Reports Server (NTRS)

    Weaver, K. A.; Gelbord, J.; Yaqoob, T.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    We find that variability of the iron K alpha line is common in Seyfert 1 galaxies. Using data from the ASCA archive for objects that have been observed more than once during the mission, we study the time-averaged spectra from individual observations, thereby probing variability on timescales that range from days to years. Since the statistics of the data do not warrant searches for line variability in terms of a complex physical model, we use a simple Gaussian to model the gross shape of the line and then use the centroid energy, intensity, and equivalent width as robust indicators of changes in the line profile. We find that approximately 70% of Seyfert 1 galaxies (10 out of 15) show variability in at least one of these parameters: the centroid energy, intensity, and equivalent width vary in six, four, and eight sources, respectively. Because of the low signal-to-noise ratio, limited sampling, and time averaging, we consider these results to represent lower limits to the rate of incidence of variability. In most cases changes in the line do not appear to track changes in the continuum. In particular, we find no evidence for variability of the line intensity in NGC 4151, suggesting an origin in a region larger than the putative accretion disk, where most of the iron line has been thought to originate. Mrk 279 is investigated on short timescales. The time-averaged effective line energy (as measured by the Gaussian center energy, which is weighted by emission in the entire line profile) is 6.5 keV in the galaxy rest frame. As the continuum flux increases by 20% in a few hours, the Fe K line responds within approximately 10,000 seconds with the effective line energy increasing by 0.22 keV (approximately 10,500 kilometers per second). We also examine the ROSAT PSPC spectrum of Mrk 279 but find inconsistencies with ASCA. Problems with the ASCA and ROSAT calibration that affect simultaneous spectral fits at low energies are discussed in an appendix.

  7. Warm molecular gas temperature distribution in six local infrared bright Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Pereira-Santaella, Miguel; Spinoglio, Luigi; van der Werf, Paul P.; Piqueras López, Javier

    2014-06-01

    We simultaneously analyze the spectral line energy distributions (SLEDs) of CO and H2 of six local luminous infrared (IR) Seyfert galaxies. For the CO SLEDs, we used new Herschel/SPIRE FTS data (from J = 4-3 to J = 13-12) and ground-based observations for the lower-J CO transitions. The H2 SLEDs were constructed using archival mid-IR Spitzer/IRS and near-IR VLT/SINFONI data for the rotational and ro-vibrational H2 transitions, respectively. In total, the SLEDs contain 26 transitions with upper level energies between 5 and 15 000 K. A single, constant density, model (nH2 ~ 104.5-6 cm-3) with a broken power-law temperature distribution reproduces well both the CO and H2 SLEDs. The power-law indices are β1 ~ 1-3 for warm molecular gas (20 K 100 K). We show that the steeper temperature distribution (higher β) for hot molecular gas can be explained by shocks and photodissociation region (PDR) models; however, the exact β values are not reproduced by PDR or shock models alone and a combination of both is needed. We find that the three major mergers among our targets have shallower temperature distributions for warm molecular gas than the other three spiral galaxies. This can be explained by a higher relative contribution of shock excitation, with respect to PDR excitation, for the warm molecular gas in these mergers. For only one of the mergers, IRASF 05189-2524, the shallower H2 temperature distribution differs from that of the spiral galaxies. The presence of a bright active galactic nucleus in this source might explain the warmer molecular gas observed. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  8. X-ray spectral variability of Seyfert 2 galaxies

    NASA Astrophysics Data System (ADS)

    Hernández-García, L.; Masegosa, J.; González-Martín, O.; Márquez, I.

    2015-07-01

    Context. Variability across the electromagnetic spectrum is a property of active galactic nuclei (AGN) that can help constrain the physical properties of these galaxies. Nonetheless, the way in which the changes happen and whether they occur in the same way in every AGN are still open questions. Aims: This is the third in a series of papers with the aim of studying the X-ray variability of different families of AGN. The main purpose of this work is to investigate the variability pattern(s) in a sample of optically selected Seyfert 2 galaxies. Methods: We use the 26 Seyfert 2s in the Véron-Cetty and Véron catalog with data available from Chandra and/or XMM-Newton public archives at different epochs, with timescales ranging from a few hours to years. All the spectra of the same source were simultaneously fitted, and we let different parameters vary in the model. Whenever possible, short-term variations from the analysis of the light curves and/or long-term UV flux variations were studied. We divided the sample into Compton-thick and Compton-thin candidates to account for the degree of obscuration. When transitions between Compton-thick and thin were obtained for different observations of the same source, we classified it as a changing-look candidate. Results: Short-term variability at X-rays was studied in ten cases, but variations are not found. From the 25 analyzed sources, 11 show long-term variations. Eight (out of 11) are Compton-thin, one (out of 12) is Compton-thick, and the two changing-look candidates are also variable. The main driver for the X-ray changes is related to the nuclear power (nine cases), while variations at soft energies or related to absorbers at hard X-rays are less common, and in many cases these variations are accompanied by variations in the nuclear continuum. At UV frequencies, only NGC 5194 (out of six sources) is variable, but the changes are not related to the nucleus. We report two changing-look candidates, MARK 273 and NGC 7319

  9. FAR-INFRARED LINE SPECTRA OF SEYFERT GALAXIES FROM THE HERSCHEL-PACS SPECTROMETER

    SciTech Connect

    Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma; Dasyra, Kalliopi M.; Calzoletti, Luca; Malkan, Matthew A.; Tommasin, Silvia

    2015-01-20

    We observed the far-IR fine-structure lines of 26 Seyfert galaxies with the Herschel-PACS spectrometer. These observations are complemented with Spitzer Infrared Spectrograph and Herschel SPIRE spectroscopy. We used the ionic lines to determine electron densities in the ionized gas and the [C I] lines, observed with SPIRE, to measure the neutral gas densities, while the [O I] lines measure the gas temperature, at densities below ∼10{sup 4} cm{sup –3}. Using the [O I]145 μm/63 μm and [S III]33/18 μm line ratios, we find an anti-correlation of the temperature with the gas density. Various fine-structure line ratios show density stratifications in these active galaxies. On average, electron densities increase with the ionization potential of the ions. The infrared lines arise partly in the narrow line region, photoionized by the active galactic nucleus (AGN), partly in H II regions photoionized by hot stars, and partly in photo-dissociated regions. We attempt to separate the contributions to the line emission produced in these different regions by comparing our observed emission line ratios to theoretical values. In particular, we tried to separate the contribution of AGNs and star formation by using a combination of Spitzer and Herschel lines, and we found that besides the well-known mid-IR line ratios, the line ratio of [O III]88 μm/[O IV]26 μm can reliably discriminate the two emission regions, while the far-IR line ratio of [C II]157 μm/[O I]63 μm is only able to mildly separate the two regimes. By comparing the observed [C II]157 μm/[N II]205 μm ratio with photoionization models, we also found that most of the [C II] emission in the galaxies we examined is due to photodissociation regions.

  10. VizieR Online Data Catalog: The Spitzer Interacting Galaxies Survey (SIGS) (Brassington+, 2015)

    NASA Astrophysics Data System (ADS)

    Brassington, N. J.; Zezas, A.; Ashby, M. L. N.; Lanz, L.; Smith, H. A.; Willner, S. P.; Klein, C.

    2015-07-01

    All 103 galaxies in the Spitzer Interacting Galaxies Survey (SIGS) sample were observed with the IRAC and the Multiband Imaging Photometer (MIPS) on the Spitzer Space Telescope (SST). These observations were obtained through both the archive and our observing program (PID 20140; PI A. Zezas). A log of all observations (between 2003 Nov and 2008 Aug) is presented in Table 2. (4 data files).

  11. Testing for X-ray Periodicities in Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    The Deep Survey instrument on the Extreme Ultraviolet Explorer obtained long, continuous light-curves of 10 Seyfert galaxies with durations of 5-33 days each. We present a uniform reduction of these data, which account for a total of 209 days of observation. Several of the light curves are uniquely suited to a search for periodicity or QPOs in the range of hours to days that might be expected from dynamical effects in the inner accretion disks around approximately 10(exp 8) solar mass black holes. Power spectra show features in three of the longest observations that could be transient periods: 0.9 days in RX J0437.4-4711, 2.1 days in Ton S180, and 5.8 days in 1H 0419-577. These period values seem to be unrelated to the length of the observations, which are similar in the three cases, but they do roughly scale as the luminosity of the objects, which would be expected in a dynamical scenario if the black hole masses also scale with luminosity. The significance of these periods will be evaluated in a future publication by using the method of Timmer & Konig (1995), which properly takes into account the red-noise properties of AGN light curves.

  12. Herschel-SPIRE spectroscopy of nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Sacchi, N.; Spinoglio, L.; Wilson, C. D.; Kamenetzky, J.; Rangwala, N.; Rykala, A.; Isaak, K. G.; Bendo, G. J.; Bradford, M.; Glenn, J.; Maloney, P. R.; Schirm, M. R. P.; Auld, R.; Baes, M.; Barlow, M. J.; Bock, J. J.; Boselli, A.; Buat, V.; Castro-Rodriguez, N.; Chanial, P.; Charlot, S.; Ciesla, L.; Clements, D. L.; Cooray, A.; Cormier, D.; Cortese, L.; Davies, J. I.; Dwek, E.; Eales, S. A.; Elbaz, D.; Galametz, M.; Galliano, F.; Gear, W. K.; Gomez, H. L.; Griffin, M.; Hony, S.; Levenson, L. R.; Lu, N.; Madden, S.; O'Halloran, B.; Okumura, K.; Oliver, S.; Page, M. J.; Panuzzo, P.; Papageorgiou, A.; Parkin, T. J.; Perez-Fournon, I.; Pohlen, M.; Rigby, E. E.; Roussel, H.; Sauvage, M.; Schulz, B.; Smith, M. W. L.; Stevens, J. A.; Sundar, S.; Symeonidis, M.; Trichas, M.; Vaccari, M.; Vigroux, L.; Wozniak, H.; Wright, G. S.; Zeilinger, W. W.

    2011-05-01

    We present the 450-1550 GHz spectra of three nearby Seyfert galaxies (NGC1068, NGC7130 and NGC7582) taken with the Herschel SPIRE FTS. For the case of NGC1068 we reconstruct the nuclear spectral line energy distribution (SLED) of the CO lines, applying nonLTE radiative transfer and a Bayesian likelihood analysis to estimate the physical properties of the molecular gas in the circumnuclear region. Groundbased observations of the low-J transitions with high (few arcsec) angular resolution are required to reconstruct the nuclear SLED avoiding contamination from colder molecular gas on larger galactic scales. We find evidence for a very warm molecular gas component with a density ~10^3.9 cm-3, similar to that found in previous works (Papadopoulos & Seaquist 1999, Usero et al. 2004, Kamenetzky et al. 2011), but with a much higher temperature (~ 550 K instead of 20-160 K). The higher-J transitions of CO are compatible with being excited in X-ray dissociation regions (XDR). However, in order to explain the entire CO SLED a comparable contribution from photodissociation regions (PDR) is required.

  13. Hydrogen line ratios in Seyfert galaxies and low redshift quasars

    NASA Technical Reports Server (NTRS)

    Kriss, G. R.

    1984-01-01

    New observations of the Lymal alpha radiation/hydrogen alpha radiation ratio in a set of X-ray selected active galactic nuclei and an archival study of International Ultraviolet Explorer (IUE) observations of Lymal alpha low redshift quasars and Seyfert galaxies have been used to form a large sample for studying the influence of soft X-rays on the enhancement of Balmer emission in the broad line region. In common models of broad line clouds, the Balmer lines are formed deep in the interior, largely by collisional excitation. Heating within the clouds is provided by soft X-ray radiation, while Lymal alpha is formed mainly by recombination after photoionization. The ratio Lymal alpha/Halpha is expected to depend weakly on the ratio of ionizing ultraviolet luminosity to X-ray luminosity (L sub UV/l sub x). If the Lymal alpha luminosity is used as a measure of L sub UV' a weak dependence of Lymal/H alpha on the X-ray luminosity is found similar to previous results.

  14. Warm absorber in Seyfert-1 galaxies observed with ASCA.

    NASA Astrophysics Data System (ADS)

    Otani, C.; Kii, T.; Fabian, A. C.; Reynolds, C. S.; Iwasawa, K.; Inoue, H.; Tanaka, Y.; Matsuoka, M.

    1996-02-01

    The authors present the results of ASCA observations of the warm absorber in five Seyfert-1 galaxies and one quasar. The most important result is the detection of the continuous increase in O VIII absorption depth in MCG -6-30-15 within half a day with the continuum decrease. If this change is due to the recombination of O IX ions, the density and radius for increased O VIII ions should be n ⪆ 106cm-3 and R ⪉ 1017cm, respectively. It is also shown that the filling factor of the matter should be very small, implying that the warm absorber is probably clumpy. These results suggest this warm absorber as some link to the broad line region (BLR). On the other hand, no significant change in O VII was observed in MCG -6-30-15. These results are explained by two distinct warm absorbers in the line-of-sight unless some unknown reason causes the stability of O VII near the BLR; one of them corresponding to O VIII is located near the BLR, and another corresponding to O VII is located far outside from the BLR.

  15. Spitzer Observations of Extraplanar PAH Emission from Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Lehner, N.; Howk, J.

    We present Spitzer/IRAC observations of polycylic aromatic hydrocarbon (PAH) emission from interstellar material in the thick disks of normal spiral galaxies. These data show PAHs to be a common constituent of extraplanar material in spirals. The processes that displace this material from the interstellar disks of these systems do not destroy these very small grains. The dust emission features are present far above the galactic planes, extended up to about 2-4 kpc above the midplanes of the galaxies presented in this work. The total extent for which dust can be traced is about half the extent of the DIG. If it is not a sensitivity effect, this suggests that PAHs may be associated with a cold neutral medium that can not be supported at high z.

  16. Two-dimensional Spectroscopy in the Circumnuclear Region of the Seyfert 1 Ring Galaxy NGC 985

    NASA Astrophysics Data System (ADS)

    Arribas, S.; Mediavilla, E.; del Burgo, C.; García-Lorenzo, B.

    1999-02-01

    We present two-dimensional optical spectroscopy of the central region (9.4"×12.2") of the Seyfert 1 ring galaxy NGC 985 obtained with an optical fiber system (two-dimensional Fiber ISIS System). The 95 spectra presented here include the Hβ-[O III] λλ4959, 5007 emission lines and the Mg I b absorption lines, which permit the study of the distribution and kinematics of the ionized gas and the stars in two dimensions. In agreement with the results of other authors, the continuum maps show the presence of two maxima: the bright Seyfert 1 nucleus and a second nucleus located about 3.7" to the northwest. These observations confirm that this second nucleus is an extragalactic object at the same redshift as that of NGC 985. These observations indicate an anisotropic distribution of the ionized gas around the Seyfert nucleus. Despite this, the velocity field of the ionized gas shows a rather regular pattern, its general kinematic properties being similar to those found in other unperturbed spiral Seyfert galaxies. Many of the spectra in the region between the Seyfert and the secondary nucleus have asymmetric and relatively broad [O III] emission-line profiles. The kinematic center of the stellar velocity field is located in the neighborhood of the Seyfert nucleus, suggesting that this nucleus is related to the main stellar component. Therefore, these observations support the hypothesis that NGC 985 is the result of a two-galaxy collision in which the intruder (elliptical or spheroidal) galaxy would be what is now the secondary nucleus, while the Seyfert activity is associated with the nucleus of the primary disk galaxy. In spite of the strong disruption that defines the large-scale morphology of NGC 985, the stellar and ionized gas kinematics do not appear significantly perturbed in the circumnuclear region.

  17. The Nature of the Ultraviolet Continuum in Type 2 Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Heckman, T.; Krolik, J.; Meurer, G.; Calzetti, D.; Kinney, A.; Koratkar, A.; Leitherer, C.; Robert, C.; Wilson, A.

    1995-10-01

    Type 2 Seyfert nuclei are well known to contain a "featureless continuum" which makes a significant contribution in the optical and ultraviolet. However, the nature of this featureless continuum is not clear. Recent optical spectropolarimetry shows that only a minor part of the optical featureless continuum can be light from a hidden Seyfert 1 nucleus scattered into our line of sight. In this paper, we show that this is also true in the ultraviolet. We have used International Ultraviolet Explorer (IUE) spectra of 20 of the brightest type 2 Seyfert nuclei to construct an ultraviolet spectral template. While the continuum is well detected in the template, there is no detectable broad-line region (BLR). Comparing this template to a similar spectral template of type 1 Seyfert nuclei implies that no more than 20% of the Seyfert 2 template's continuum can be light from a hidden Seyfert 1 nucleus scattered by dust or warm electrons. One obvious possibility is that most of the nuclei in our sample are "pure" type 2 Seyfert galaxies that do not contain a hidden type 1 Seyfert nucleus (e.g., we have a clear view of the central engine in the ultraviolet, and it simply lacks a broad-line region). This is not compatible with the evidence that at least some Seyfert 2 galaxies can be unified with Seyfert 1 galaxies on the basis of viewing geometry, unless there are two types of Seyfert 2 galaxies. As an alternative, we consider the possibility of Seyfert 1 light scattered off very hot electrons (T > 10^7^ K). The BLR emission lines can then be broadened beyond recognition in our data. However, a scatterer this hot is inconsistent with optical spectropolarimetry. Optically-thin thermal emission from the type of warm mirror seen in NGC 1068 cannot produce the ultraviolet continuum we observe because the equivalent width of Lyα and He II λ1640 are at least an order of magnitude too small in the Seyfert 2 template, and the observed ultraviolet continuum is generally much too red to

  18. Rapid x-ray variability from the Seyfert 1 galaxy NGC 4051

    SciTech Connect

    Marshall, F.E.; Holt, S.S.; Mushotzky, R.F.; Becker, R.H.

    1983-06-15

    Strong variable x-ray emission from the nearby low-luminosity Seyfert 1 galaxy NGC 4051 has been discovered during observations with the imaging proportional counter (IPC) of the Einstein Observatory. During one 2304 s observation, the x-ray flux more than doubled in an approximately linear fashion, and a 70% increase for 150 s was seen during another 968 s observation. We present evidence that the x-ray spectrum of NGC 4051 is unusually soft compared with Seyfert 1 galaxies or OSOs. The emission mechanism is probably not synchrotron or synchrotron self-Compton, but the emission can be plausibly explained by various black hole accretion models.

  19. Photometry of the 'Seyfert Sextet' /VV 115/ and the anonymous galaxy 1558.2 + 2100

    NASA Technical Reports Server (NTRS)

    Martins, D. H.; Chincarini, G.

    1976-01-01

    Photometric observations of the Seyfert Sextet (VV 115) are analyzed. Apparent integrated magnitudes are derived relative to the sky brightness, and isophotal maps are given for the field. No evidence for interaction between NGC 6027 and d is found. Luminosity profiles are given for NGC 6027, a, b, and d, with the d profile having been corrected for seeing effects in one dimension. The corrected profile parameters favor the interpretation of d as a highly luminous background galaxy at its cosmological distance. The nearby anonymous galaxy 1558.2 + 2100 is similarly studied, with no clear evidence of photometric peculiarities detected. Its interaction with the Seyfert Sextet appears to be excluded.

  20. Bipolar Nuclear Outflow from the Seyfert 1 Galaxy NGC 5548

    NASA Astrophysics Data System (ADS)

    Wrobel, J. M.

    1994-12-01

    The S0/Sa galaxy NGC 5548 hosts a Seyfert 1 nucleus. Echo mapping of its broad optical-line-emitting region yields a radial extent R <~ 20 light days = (1)/(60) pc, or 70 h microarcseonds for H_0 = 100 h km s(-1) Mpc(-1) (Peterson 1993). Using data from larger radii, what boundary conditions can be imposed on the geometry and velocity field of the broad line region? R <~ 1400 h(-1) pc: Bipolar radio continuum lobes straddle a central radio component in NGC 5548. These lobes, which emit optically-thin synchrotron radiation with a 4-cm power of 10(21) h(-2) W Hz(-1) , trace bipolar outflow from the nucleus (Wilson & Ulvestad 1982; Wrobel 1994). R <~ 720 h(-1) pc: The radio lobes of NGC 5548 share the elongation position angle of the [OIII] narrow-line gas, with the broadest known line widths occuring NW of the nucleus at these radii (Wilson et al. 1989). This hints that some narrow-line gas receives additional mechanical energy from the bipolar outflow feeding the radio lobes, a situation analogous to the narrow-line superbubble in NGC 3079 (Veilleux et al. 1994). R <~ 10 h(-1) pc: Blueshifted absorption in the broad CIV lines proves that some gas is flowing out of the nucleus of NGC 5548, with observed speeds of 1200 km s(-1) relative to systemic (Shull & Sachs 1993). This absorption line outflow may have, or be able to achieve, a bipolar shape via the disk-focusing scheme proposed for NGC 3079 (Duric & Seaquist 1988; Veilleux et al. 1994).

  1. Absorption and Reflection in the Seyfert 2 Galaxy NGC4388

    NASA Astrophysics Data System (ADS)

    Blanco, Philip

    We propose to observe NGC4388, the brightest Seyfert 2 observed in hard X-rays (Johnson et al. 1994). The determination of the hard X-ray/gamma-ray spectrum of this object will test the unified AGN model, according to which Seyfert 2s contain the same intrinsic hard X-ray/Gamma-ray sources as Seyfert 1s, but are seen through an optically thick obscuring torus. A measurement of the hard X-ray spectrum and any short term time variability will then allow us to model the physical processes responsible for the emission. Such studies are also important in assessing the contribution of Seyfert 2s to the cosmic X-ray background.

  2. The Variability of Seyfert 1.8 and 1.9 Galaxies at 1.6 Microns.

    PubMed

    Quillen; Shaked; Alonso-Herrero; McDonald; Lee; Rieke; Rieke

    2000-03-20

    We present a study of Seyfert 1.5-2.0 galaxies observed at two epochs with the Hubble Space Telescope (HST) at 1.6 µm. We find that unresolved nuclear emission from nine of 14 nuclei varies at the level of 10%-40% on timescales of 0.7-14 months, depending upon the galaxy. A control sample of Seyfert galaxies lacking unresolved sources and galaxies lacking Seyfert nuclei show less than 3% instrumental variation in equivalent aperture measurements. This proves that the unresolved sources are nonstellar and associated with the central parsecs of active galactic nuclei. Unresolved sources in Seyfert 1.8 and 1.9 galaxies are not usually detected in HST optical surveys; however, high angular resolution infrared observations will provide a way to measure time delays in these galaxies. PMID:10702122

  3. A study of the structure and kinematics of the narrow-line region in Seyfert galaxies

    SciTech Connect

    Veilleux, S.

    1989-01-01

    The results of a high resolution study of the narrow emission line profiles of 16 Seyfert galaxies are presented. It is shown that the line profile parameters published in earlier low resolution studies are sometimes strongly influenced by resolution effects. In spite of these important systematic errors, many of the results derived from low resolution data are confirmed in the high resolution data. The narrow line profiles of Seyfert galaxies have a stronger base relative to core than a Gaussian. Most of the emission lines present a blueward asymmetry in the lower portion of their profile. In some galaxies, the line widths and/or line asymmetries are correlated with the ionization potential and/or critical density of the lines. There is a weak correlation between the line asymmetry and the dust content of the narrow line region (NLR). The large scatter in this relation, the absence of a similar correlation in Seyfert 1 to 1.5 galaxies, and the presence of a blue asymmetry in galaxies with dustfree line-emitting regions suggest that dust obscuration is not the only mechanism responsible for the line asymmetry in active galaxies. An optically-thick disk close to the nucleus is proposed as the other source of line asymmetry. An important result is that the host galaxy is probably playing a role in the kinematics of some of the gas in the NLR. A multicomponent model of the NLR is proposed to explain these results.

  4. Searching for Distant Galaxies with HST and Spitzer

    NASA Astrophysics Data System (ADS)

    Senchyna, Peter; Ashby, Matthew; Hora, Joseph L.; Candels, S.-Candels

    2015-01-01

    The recently completed Spitzer-Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (S-CANDELS) provides an extremely deep NIR view of five extragalactic fields: COSMOS, EGS, UDS, HDF-N, and ECDFS. The addition of this deep near-infrared photometry to the existing CANDELS HST imaging is expected to improve redshift and stellar population parameter estimation, and enable selection of galaxies to higher redshift by capturing the 4000 Angstrom break out to 3.6 microns. Here we present an isolated galaxy sample based upon IRAC detection that is free from the effects of source confusion. The sample includes both objects for which CANDELS HST photometry is available, and a small number of objects detected by S-CANDELS but not by WFC3/F160W. We derive photometric redshifts for the matched objects, and demonstrate the efficacy of an IRAC color cut in selecting high-redshift sources. In addition, we apply aperture photometry to the HST images of apparent F160W dropouts. We explore the properties of the high-significance dropouts at other wavelengths, and attempt to distinguish between heavily-shrouded AGN and sources at redshift greater than 7.This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  5. Extended far-infrared emission and star formation in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Marston, A. P.

    1994-01-01

    An investigation into the extended distribution of far-infrared (FIR) emission associated with nearby Seyfert galaxies is made using a set of MEM reconstructions of IRAS Chopped Photometric Channel (CPC) data (Marston 1993). The data is compared to a set of HII/starburst galaxy images similarly processed in order to compare distributions and FIR color properties. It is shown that the central 1 kpc or so of Seyfert galaxies show extended FIR emission. FIR colors suggest that the bulk of this emission is not directly associated with an active nucleus. They further suggest that the origins of the majority of the emission is from heated dust associated with star formation surrounding the nucleus rather than dust heated by the active nucleus. Nearby Seyfert galaxies are shown to have a higher concentration of far-infrared emission from their centers than the HII/starburst galaxies and a number appear to reside in disk galaxies with relatively low ongoing star formation in their disks. An example of this is NGC 7582 which has a smooth disk but an active nucleus/starbust center.

  6. Hα kinematics of the Spitzer Infrared Nearby Galaxies Survey - II

    NASA Astrophysics Data System (ADS)

    Dicaire, I.; Carignan, C.; Amram, P.; Hernandez, O.; Chemin, L.; Daigle, O.; de Denus-Baillargeon, M.-M.; Balkowski, C.; Boselli, A.; Fathi, K.; Kennicutt, R. C.

    2008-04-01

    This is the second part of an Hα kinematics follow-up survey of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample. The aim of this paper is to shed new light on the role of baryons and their kinematics and on the dark/luminous matter relation in the star-forming regions of galaxies, in relation with studies at other wavelengths. The data for 37 galaxies are presented. The observations were made using Fabry-Perot interferometry with the photon-counting camera FaNTOmM on four different telescopes, namely the Canada-France-Hawaii 3.6-m, the ESO La Silla 3.6-m, the William Herschel 4.2-m and the Observatoire du mont Mégantic 1.6-m telescopes. The velocity fields are computed using custom IDL routines designed for an optimal use of the data. The kinematical parameters and rotation curves are derived using the GIPSY software. It is shown that non-circular motions associated with galactic bars affect the kinematical parameters fitting and the velocity gradient of the rotation curves. This leads to incorrect determinations of the baryonic and dark matter distributions in the mass models derived from those rotation curves. Based on observations made with the ESO 3.60-m telescope at La Silla Observatories under programme ID 076.B-0859 and on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France and the University of Hawaii. E-mail: isabelle@astro.umontreal.ca (ID);claude.carignan@umontreal.ca (CC) ‡ Visiting Astronomer, Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France and the University of Hawaii.

  7. TESTING THE EVOLUTIONARY SEQUENCE BETWEEN HIDDEN BROAD-LINE REGION (HBLR) AND NON-HBLR SEYFERT 2 GALAXIES WITH THE 4000 A BREAK STRENGTHS

    SciTech Connect

    Yu, Po-Chieh; Hwang, Chorng-Yuan; Huang, Kui-Yun; Ohyama, Youichi E-mail: hwangcy@astro.ncu.edu.tw E-mail: ohyama@asiaa.sinica.edu.tw

    2013-05-01

    We compare the 4000 A break (D{sub n} (4000)) strength in the central kpc of hidden broad-line region (HBLR) and non-HBLR Seyfert 2 galaxies to investigate the origin of these galaxies. Our results show that the D{sub n} (4000) strengths in the nuclear regions of the non-HBLR Seyfert 2 galaxies are larger than those in the HBLR galaxies. We also show that the D{sub n} (4000) strength is not related to the morphology of host galaxies. These results imply that the non-HBLR Seyfert 2 galaxies have an older stellar population in nuclear regions than the HBLR galaxies. This suggests that an evolutionary connection might exist between non-HBLR and HBLR Seyfert 2 galaxies. We propose a potential evolutionary scenario and a modified unification model for Seyfert galaxies. In this scheme, Seyfert 1 and HBLR Seyfert 2 galaxies evolve into unabsorbed and absorbed non-HBLR Seyfert 2 galaxies. We also discuss the implications of our results in the hydrogen column density distribution of the non-HBLR Seyfert 2 galaxies.

  8. Hubble Space Telescope images of the Seyfert galaxies NGC 5929 and MCG 8-11-11

    NASA Technical Reports Server (NTRS)

    Bower, Gary A.; Wilson, Andrew S.; Mulchaey, John S.; Miley, George K.; Heckman, Timothy M.; Krolik, Julian H.

    1994-01-01

    We present the initial results of a program to obtain high resolution images of Seyfert galaxies with the Planetary Camera aboard the Hubble Space Telescope (HST). In this paper we discuss the images of the type 2 Seyfert NGC 5929 and the type 1.5 Seyfert MCG 8-11-11 (= UGC 3374). The images were obtained in the emission lines of (O III) lambda lambda 4959 and 5007 A and H alpha + (N II) lambda lambda 6548 and 6583 A and their adjacent continua. The high-excitation gas in the narrow line region (NLR) of NGC 5929 is resolved into individual clouds in the central 1 sec .5. Although the (O III) emission is clearly not spherically symmetric with respect to the nucleus, it does not define a distinct 'bicone' morphology, as observed by the HST in a few other Seyfert galaxies. We find no direct evidence for the reddening and/or obscuration effects characteristic of a dusty torus, which, in the context of 'unified models', is expected to obscure the active galactic nucleus (AGN) in type 2 Seyfert galaxies. The correspondence between the emission line gas and the radio morphology suggests that the structure of the NLR in NGC 5929 is governed by matter ejected from the AGN. A comparison of the recombination rate of hydrogen in the brightest emission line cloud with an upper limit on the ionizing luminosity emitted toward Earth provides no evidence that the central ionizing source radiates anisotropically. The images of MCG 8-11-11 show only an unresolved nuclear source. No emission line gas associated with the extended radio source is detected. We estimate upper limits on the intensity of extended line emission in this galaxy and examine their significance.

  9. VizieR Online Data Catalog: Atlas of HST STIS spectra of Seyfert galaxies (Spinelli+, 2006)

    NASA Astrophysics Data System (ADS)

    Spinelli, P. F.; Storchi-Bergmann, T.; Brandt, C. H.; Calzetti, D.

    2008-05-01

    We present a compilation of spectra of 101 Seyfert galaxies obtained with the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS), covering the UV and/or optical spectral range. Information on all the available spectra have been collected in a Mastertable, which is a very useful tool for anyone interested in a quick glance at the existent STIS spectra for Seyfert galaxies in the HST archive, and it can be recovered electronically. Nuclear spectra of the galaxies have been extracted in windows of 0.2" for an optimized sampling (as this is the slit width in most cases) and combined in order to improve the signal-to-noise ratio and provide the widest possible wavelength coverage. These combined spectra are also available electronically, at http://www.if.ufrgs.br/~pat/atlas.htm . (3 data files).

  10. The broad emission line and continuum variations of Seyfert galaxies. I - Time scales and amplitudes

    NASA Technical Reports Server (NTRS)

    Rosenblatt, Edward I.; Malkan, Matthew A.; Sargent, Wallace L. W.; Readhead, Anthony C. S.

    1992-01-01

    Spectroscopic observations of 13 Seyfert 1 galaxies made from 1979 to 1984 at Palomar and Steward Observatories were analyzed for Balmer-line and optical continuum variability. The majority of the galaxies showed significant variations, particularly in the continuum. Typical peak-to-peak changes for H-beta and H-gamma integrated line fluxes were 100-200 percent, while the continua varied by 200-350 percent. In several cases, Balmer-line and continuum variations were found to be strongly correlated, as expected for photoionization by a central continuum source. However, these correlations were found to be highly nonlinear. Significant correlations were found between variability amplitude and global AGN properties such as luminosity. Moreover, a significant number of variations occurring on short time scales constrains the size of the broad-line region in Seyfert galaxies to about 90 lt-days across or less.

  11. Hubble Space Telescope Imaging of the Circumnuclear Environments of the CfA Seyfert Galaxies: Nuclear Spirals and Fueling

    NASA Technical Reports Server (NTRS)

    Pogge, Richard W.; Martini, Paul

    2002-01-01

    We present archival Hubble Space Telescope (HST) images of the nuclear regions of 43 of the 46 Seyfert galaxies found in the volume limited,spectroscopically complete CfA Redshift Survey sample. Using an improved method of image contrast enhancement, we created detailed high-quality " structure maps " that allow us to study the distributions of dust, star clusters, and emission-line gas in the circumnuclear regions (100-1000 pc scales) and in the associated host galaxy. Essentially all of these Seyfert galaxies have circumnuclear dust structures with morphologies ranging from grand-design two-armed spirals to chaotic dusty disks. In most Seyfert galaxies there is a clear physical connection between the nuclear dust spirals on hundreds of parsec scales and large-scale bars and spiral arms in the host galaxies proper. These connections are particularly striking in the interacting and barred galaxies. Such structures are predicted by numerical simulations of gas flows in barred and interacting galaxies and may be related to the fueling of active galactic nuclei by matter inflow from the host galaxy disks. We see no significant differences in the circumnuclear dust morphologies of Seyfert 1s and 2s, and very few Seyfert 2 nuclei are obscured by large-scale dust structures in the host galaxies. If Sevfert 2s are obscured Sevfert Is, then the obscuration must occur on smaller scales than those probed by HST.

  12. A global look at X-ray time lags in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Kara, E.; Alston, W.; Fabian, A.

    2016-05-01

    X-ray reverberation, where light-travel time delays map out the compact geometry around the inner accretion flow in supermassive black holes, has been discovered in several of the brightest, most variable and well-known bare Seyfert galaxies. In this work, we expand the study of X-ray time lags to all Seyfert galaxies in the XMM-Newton archive above a nominal rms and exposure level. We find that reverberation is found in > 50% of sources (with > 99% confidence). We also find that the low-frequency hard lag (which is likely associated with the coronal emission) is found in > 80% of sources, suggesting that most sources with X-ray variability show intrinsic variability from the nuclear region. We update the known iron K lag amplitude vs. black hole mass relation.

  13. Connection between the rapidly varying and smooth components in the light curves of Seyfert galaxies

    SciTech Connect

    Gagen-Torn, V.A.

    1987-11-01

    It is shown that for some Seyfert galaxies whose light curves contain a fast (burst) component and a smooth component (components I and II) the amplitude of the flux variation of component I is proportional to the flux of component II. Since components I and II are also identical in their color characteristics, it is very probable that the variability is due to a single smoothly varying and fluctuating source.

  14. Nuclear star formation activity and black hole accretion in nearby Seyfert galaxies

    SciTech Connect

    Esquej, P.; Alonso-Herrero, A.; Hernán-Caballero, A.; González-Martín, O.; Ramos Almeida, C.; Rodríguez Espinosa, J. M.; Roche, P.; Mason, R. E.; Díaz-Santos, T.; Levenson, N. A.; Aretxaga, I.; Packham, C.

    2014-01-01

    Recent theoretical and observational works indicate the presence of a correlation between the star-formation rate (SFR) and active galactic nucleus (AGN) luminosity (and, therefore, the black hole accretion rate, M-dot {sub BH}) of Seyfert galaxies. This suggests a physical connection between the gas-forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. We compiled the largest sample of Seyfert galaxies to date with high angular resolution (∼0.''4-0.''8) mid-infrared (8-13 μm) spectroscopy. The sample includes 29 Seyfert galaxies drawn from the AGN Revised Shapley-Ames catalog. At a median distance of 33 Mpc, our data allow us to probe nuclear regions on scales of ∼65 pc (median value). We found no general evidence of suppression of the 11.3 μm polycyclic aromatic hydrocarbon (PAH) emission in the vicinity of these AGN, and we used this feature as a proxy for the SFR. We detected the 11.3 μm PAH feature in the nuclear spectra of 45% of our sample. The derived nuclear SFRs are, on average, five times lower than those measured in circumnuclear regions of 600 pc in size (median value). However, the projected nuclear SFR densities (median value of 22 M {sub ☉} yr{sup –1} kpc{sup –2}) are a factor of 20 higher than those measured on circumnuclear scales. This indicates that the SF activity per unit area in the central ∼65 pc region of Seyfert galaxies is much higher than at larger distances from their nuclei. We studied the connection between the nuclear SFR and M-dot {sub BH} and showed that numerical simulations reproduce our observed relation fairly well.

  15. Nuclear Star Formation Activity and Black Hole Accretion in Nearby Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Esquej, P.; Alonso-Herrero, A.; González-Martín, O.; Hönig, S. F.; Hernán-Caballero, A.; Roche, P.; Ramos Almeida, C.; Mason, R. E.; Díaz-Santos, T.; Levenson, N. A.; Aretxaga, I.; Rodríguez Espinosa, J. M.; Packham, C.

    2014-01-01

    Recent theoretical and observational works indicate the presence of a correlation between the star-formation rate (SFR) and active galactic nucleus (AGN) luminosity (and, therefore, the black hole accretion rate, \\dot{M}_BH) of Seyfert galaxies. This suggests a physical connection between the gas-forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. We compiled the largest sample of Seyfert galaxies to date with high angular resolution (~0.''4-0.''8) mid-infrared (8-13 μm) spectroscopy. The sample includes 29 Seyfert galaxies drawn from the AGN Revised Shapley-Ames catalog. At a median distance of 33 Mpc, our data allow us to probe nuclear regions on scales of ~65 pc (median value). We found no general evidence of suppression of the 11.3 μm polycyclic aromatic hydrocarbon (PAH) emission in the vicinity of these AGN, and we used this feature as a proxy for the SFR. We detected the 11.3 μm PAH feature in the nuclear spectra of 45% of our sample. The derived nuclear SFRs are, on average, five times lower than those measured in circumnuclear regions of 600 pc in size (median value). However, the projected nuclear SFR densities (median value of 22 M ⊙ yr-1 kpc-2) are a factor of 20 higher than those measured on circumnuclear scales. This indicates that the SF activity per unit area in the central ~65 pc region of Seyfert galaxies is much higher than at larger distances from their nuclei. We studied the connection between the nuclear SFR and \\dot{M}_BH and showed that numerical simulations reproduce our observed relation fairly well.

  16. Discovery of Relativistic Outflows in the Seyfert Galaxies Ark 564 and Mrk 590

    NASA Astrophysics Data System (ADS)

    Gupta, A.; Mathur, S.

    2014-07-01

    Outflows are ubiquitous in AGNs, manifested by blueshifted absorption lines in the soft X-ray and UV bands and have outflow velocities of 100-1000 km s^{-1}. The discovery of ultra-fast outflows (0.1 c) exhibited by blueshifted absorption lines in the hard X-ray band has added an intriguing aspect to the rich field of AGN outflows. The significance of these absorption line detections is often questioned and with only a few lines observed, accurate parametrization of the photoionized plasma becomes difficult. We recently discovered relativistic outflows in the soft X-ray band in two Seyfert galaxies; these detections are robust and alleviate earlier concerns about statistical significance of the lines in the hard X-ray band. I will discuss the our recent results on the discovery of high velocity outflows in the narrow line Seyfert 1 galaxies Ark 564 and Mrk 590. These absorbers are identified through multiple absorption lines at blueshift of 0.1c-0.17c detected in the Chandra HETG-MEG spectra. These high-velocity outflows have ionization parameter and column density typical of low-velocity outflows, but much higher velocity, probing a distinct region in the velocity versus ionization/column parameter space. The presence of such relativistic outflows in Seyfert galaxies poses a challenge to theoretical models of AGN winds. I will briefly discuss existing models and future prospects.

  17. Discovery of Relativistic Outflows in the Seyfert Galaxies Ark 564 and Mrk 590

    NASA Astrophysics Data System (ADS)

    Gupta, Anjali; mathur, Smita

    2015-08-01

    Outflows are ubiquitous in AGNs, manifested by blueshifted absorption lines in the soft X-ray and UV bands and have outflow velocities of 100-1000 km s-1. The discovery of ultra-fast outflows (0.1 c) exhibited by blueshifted absorption lines in the hard X-ray band has added an intriguing aspect to the rich field of AGN outflows. The significance of these absorption line detections is often questioned and with only a few lines observed, accurate parametrization of the photoionized plasma becomes difficult. We recently discovered relativistic outflows in the soft X-ray band in two Seyfert galaxies; these detections are robust and alleviate earlier concerns about statistical significance of the lines in the hard X-ray band. I will discuss the our recent results on the discovery of high velocity outflows in the narrow line Seyfert 1 galaxies Ark 564 and Mrk 590. These absorbers are identified through multiple absorption lines at blueshift of 0.1c-0.17c detected in the Chandra HETG-MEG spectra. These high-velocity outflows have ionization parameter and column density typical of low-velocity outflows, but much higher velocity, probing a distinct region in the velocity versus ionization/column parameter space. The presence of such relativistic outflows in Seyfert galaxies poses a challenge to theoretical models of AGN winds. I will briefly discuss existing models and future prospects.

  18. A UNIQUE X-RAY UNABSORBED SEYFERT 2 GALAXY: IRAS F01475-0740

    SciTech Connect

    Huang Xingxing; Wang Junxian; Tan Ying; Yang Huan; Huang Yafang E-mail: jxw@ustc.edu.cn

    2011-06-10

    X-ray unabsorbed Seyfert 2 galaxies appear to have X-ray absorption column densities that are too low (N{sub H} < 10{sup 22} cm{sup -2}) to explain the absence of broad emission lines in their optical spectra, challenging the standard active galactic nucleus (AGN) unification model. In this Letter, we report Suzaku exposure on the X-ray unabsorbed Seyfert 2 galaxy IRAS F01475-0740, in which a hidden broad-line region was detected through spectropolarimetric observation. The X-ray data show rapid and significant variations on timescales down to 5 ks, indicating that we are viewing its central engine directly. A newly obtained optical spectrum and previous optical/X-ray data suggest that state transition is unlikely in this source. These make IRAS F01475-0740 a very peculiar X-ray unabsorbed Seyfert 2 galaxy which can only be explained by absorption from materials with abnormally high dust-to-gas ratio (by a factor of >4 larger than Galactic). This is in contrast to most AGNs, which typically show dust-to-gas ratios 3-100 times lower than the Galactic.

  19. A Kinematic Study of the Nuclear Stellar Populations in Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    García-Rissmann, Aurea; Cid Fernandes, Roberto; Asari, N. V.; Vega, Luis Rodolfo; Schmitt, Henrique; González Delgado, Rosa

    2005-05-01

    Recent studies in the optical and UV have detected circumnuclear starbursts in 40% of nearby Seyfert-2 galaxies; about half of the remaining 60% present a UV excess whose nature is not well known, mainly because of the limitations of the current stellar population analysis techniques in the optical and UV domains. A possible way to circumvent these difficulties is to use a determination of the mass-to-light (M/L) ratio, obtained with a combination of velocity dispersion measurements and photometric information. Dynamical information in AGN (particularly in type 2) is better determined from NIR spectroscopic data, where the stellar absorption features are less affected by the nuclear continuum dilution. In this work, we present preliminary results of a spectroscopic survey of more than 60 Seyfert nuclei (mainly Seyfert 2s), conducted at ESO/La Silla and at KPNO. For many of these objects we have complementary data, such as HST images, optical and (in some cases) UV spectroscopy. The long-slit spectroscopy for the purpose of this project was performed around the NIR Ca II triplet lines at 8498, 8542 and 8662Å. Here we describe the analysis steps taken so far, and present the first results concerning velocity dispersion measurements in nuclear regions. With these data we aim to investigate the ambiguous Seyfert 2 nuclei nature, thus contributing to a better understanding of the AGN-starburst connection.

  20. The morphology of minor axis gaseous outflows in edge-on Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Robitaille, T. P.; Rossa, J.; Bomans, D. J.; van der Marel, R. P.

    2007-03-01

    Context: Spiral galaxies often have extended outflows that permeate beyond the region of the disk. Such outflows have been seen both in starburst galaxies, actively star forming galaxies and galaxies with an AGN. In the latter galaxies it is unknown whether the large-scale outflows are driven by star formation activity or purely by the active nucleus. Aims: The aim of our investigation is to study the frequency of extended minor-axis outflows in edge-on Seyfert galaxies to investigate the role of the AGN, the circumnuclear environment and star formation activity within the disk regions, and their importance for IGM enrichment on large scales. Methods: We obtained optical narrowband imaging observations of a distance limited, northern hemisphere sample of 14 edge-on Seyfert spiral galaxies. Because of the distance-limited nature of the sample, it is restricted to relatively low-luminosity Seyfert galaxies. The data were obtained with BUSCA attached to the 2.2 m telescope at the Calar Alto observatory. Narrowband imaging in two different ionizational stages (Hα and [O iii] ) was performed to attempt a discrimination between processes associated with the active nucleus and those connected to star forming activity within the disk. The median 3-σ sensitivities for detection of high-latitude extended emission in the sample galaxies are 3.6×10-17 erg s-1 cm-2 arcsec-2 for the Hα images and 6.9×10-17 erg s-1 cm-2 arcsec-2 for the [O iii] images. We use the data to study the distribution of extraplanar emission with respect to the AGN and the underlying disk H ii regions. Results: The Hα morphology of the Seyfert galaxies is usually complex, but only in three out of 14 galaxies did we find evidence for minor axis disk outflows. At the sensitivity of our observations [O iii] emission is generally detected only in the nuclear region. For Ark 79 we present the first evidence of a secondary nuclear component, best visible in the [O iii] image, which has a linear

  1. Deep Optical Imaging of a Compact Group of Galaxies: Seyfert's Sextet

    NASA Astrophysics Data System (ADS)

    Nishiura, Shingo; Murayama, Takashi; Shimada, Masashi; Sato, Yasunori; Nagao, Tohru; Molikawa, Kohji; Taniguchi, Yoshiaki; Sanders, D. B.

    2000-11-01

    To investigate the dynamical status of Seyfert's Sextet (SS), we have obtained a deep optical (VR+I) image of this group. Our image shows that a faint envelope, down to a surface brightness μoptical(AB)~=27 mag arcsec-2, surrounds the member galaxies. This envelope is irregular in shape. It is likely that this shape is attributed either to recent-past or to ongoing galaxy interactions in SS. If the member galaxies have experienced a number of mutual interactions over a long timescale, the shape of the envelope should be rounder. Therefore, the irregularly shaped morphology suggests that SS is in an early phase of dynamical interaction among the member galaxies. It is interesting to note that the soft X-ray image obtained with ROSAT (Pildis, Bregman, & Evrard) is significantly similar in morphology. We discuss the possible future evolution of SS briefly.

  2. The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei

    NASA Technical Reports Server (NTRS)

    Ptak, R.; Stoner, R.

    1974-01-01

    The physical conditions in a high density hydrogen gas heated and ionized by suprathermal protons were investigated, with application to the gas in the nuclear region of Seyfert galaxies. The gas is assumed optically thick to Lyman and Balmer line radiation. Mechanisms by which the radiation from the gas can balance the heating by the fast protons were investigated, and minimum values for the mass of gas were estimated. Under certain conditions, the suprathermal atoms themselves can cool the ambient gas by rescattering the line radiation into the optically thin region in the wings of the line. This mechanism, called optical reverberation, can enhance the broad component of the hydrogen lines produced by inelastic atomic collisions and yield line widths consistent with those observed in Seyfert and quasar spectra. Also discussed is the possibility of achieving dynamic equilibrium of the ambient gas by balancing the momentum transfer from the suprathermals with gravitational attraction of a massive central source.

  3. The Role of Radiation Pressure in the Narrow Line Regions of Seyfert Host Galaxies

    NASA Astrophysics Data System (ADS)

    Davies, Rebecca L.; Dopita, Michael A.; Kewley, Lisa; Groves, Brent; Sutherland, Ralph; Hampton, Elise J.; Shastri, Prajval; Kharb, Preeti; Bhatt, Harish; Scharwächter, Julia; Jin, Chichuan; Banfield, Julie; Zaw, Ingyin; James, Bethan; Juneau, Stéphanie; Srivastava, Shweta

    2016-06-01

    We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-active galactic nucleus (AGN) mixing curves on standard emission line diagnostic diagrams, which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ˜ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ˜ 0 to ‑3.2 ≲ log U ≲ ‑3.4. Where radiation pressure is dominant, the AGN regulates the density of the interstellar medium on kiloparsec scales and may therefore have a direct impact on star formation activity and/or the incidence of outflows in the host galaxy to scales far beyond the zone of influence of the black hole. We find that both radiation pressure dominated and gas pressure dominated ENLRs are dynamically active with evidence for outflows, indicating that radiation pressure may be an important source of AGN feedback even when it is not dominant over the entire ENLR.

  4. Mid-infrared interferometry of Seyfert galaxies: Challenging the Standard Model

    NASA Astrophysics Data System (ADS)

    López-Gonzaga, N.; Jaffe, W.

    2016-06-01

    Aims: We aim to find torus models that explain the observed high-resolution mid-infrared (MIR) measurements of active galactic nuclei (AGN). Our goal is to determine the general properties of the circumnuclear dusty environments. Methods: We used the MIR interferometric data of a sample of AGNs provided by the instrument MIDI/VLTI and followed a statistical approach to compare the observed distribution of the interferometric measurements with the distributions computed from clumpy torus models. We mainly tested whether the diversity of Seyfert galaxies can be described using the Standard Model idea, where differences are solely due to a line-of-sight (LOS) effect. In addition to the LOS effects, we performed different realizations of the same model to include possible variations that are caused by the stochastic nature of the dusty models. Results: We find that our entire sample of AGNs, which contains both Seyfert types, cannot be explained merely by an inclination effect and by including random variations of the clouds. Instead, we find that each subset of Seyfert type can be explained by different models, where the filling factor at the inner radius seems to be the largest difference. For the type 1 objects we find that about two thirds of our objects could also be described using a dusty torus similar to the type 2 objects. For the remaining third, it was not possible to find a good description using models with high filling factors, while we found good fits with models with low filling factors. Conclusions: Within our model assumptions, we did not find one single set of model parameters that could simultaneously explain the MIR data of all 21 AGN with LOS effects and random variations alone. We conclude that at least two distinct cloud configurations are required to model the differences in Seyfert galaxies, with volume-filling factors differing by a factor of about 5-10. A continuous transition between the two types cannot be excluded.

  5. A SPITZER-SELECTED GALAXY CLUSTER AT z = 1.62

    SciTech Connect

    Papovich, C.; Finkelstein, K. D.; Finkelstein, S. L.; Tran, K.-V.; Momcheva, I.; McCarthy, P.; Willmer, C. N. A.; Rieke, M.; Sivanandam, S.; Brodwin, M.; Dunlop, J. S.; McLure, R. J.; Farrah, D.; Khan, S. A.; Lotz, J.; Rudnick, G.; Pacaud, F.; Pierre, M.

    2010-06-20

    We report the discovery of a galaxy cluster at z = 1.62 located in the Spitzer Wide-Area Infrared Extragalactic survey XMM-LSS field. This structure was selected solely as an overdensity of galaxies with red Spitzer/Infrared Array Camera colors, satisfying ([3.6] - [4.5]){sub AB}> - 0.1 mag. Photometric redshifts derived from the Subaru XMM Deep Survey (BViz bands), the UKIRT Infrared Deep Survey-Ultra-Deep Survey (UKIDSS-UDS, JK bands), and from the Spitzer Public UDS survey (3.6-8.0 {mu}m) show that this cluster corresponds to a surface density of galaxies at z {approx} 1.6 that is >20{sigma} above the mean at this redshift. We obtained optical spectroscopic observations of galaxies in the cluster region using IMACS on the Magellan telescope. We measured redshifts for seven galaxies in the range z = 1.62-1.63 within 2.8 arcmin (<1.4 Mpc) of the astrometric center of the cluster. A posteriori analysis of the XMM data in this field reveal a weak (4{sigma}) detection in the [0.5-2 keV] band compatible with the expected thermal emission from such a cluster. The color-magnitude diagram of the galaxies in this cluster shows a prominent red sequence, dominated by a population of red galaxies with (z - J)>1.7 mag. The photometric-redshift probability distributions for the red galaxies are strongly peaked at z = 1.62, coincident with the spectroscopically confirmed galaxies. The rest-frame (U - B) color and scatter of galaxies on the red sequence are consistent with a mean luminosity-weighted age of 1.2 {+-} 0.1 Gyr, yielding a formation redshift z-bar{sub f}=2.35{+-}0.10, and corresponding to the last significant star formation period in these galaxies.

  6. SPITZER QUASAR AND ULIRG EVOLUTION STUDY (QUEST). IV. COMPARISON OF 1 Jy ULTRALUMINOUS INFRARED GALAXIES WITH PALOMAR-GREEN QUASARS

    SciTech Connect

    Veilleux, S.; Rupke, D. S. N.; Kim, D.-C. E-mail: drupke@ifa.hawaii.edu

    2009-06-15

    We report the results from a comprehensive study of 74 ultraluminous infrared galaxies (ULIRGs) and 34 Palomar-Green (PG) quasars within z {approx} 0.3 observed with the Spitzer Infrared Spectrograph (IRS). The contribution of nuclear activity to the bolometric luminosity in these systems is quantified using six independent methods that span a range in wavelength and give consistent results within {approx}{+-}10%-15% on average. This agreement suggests that deeply buried active galactic nuclei (AGNs) invisible to Spitzer IRS but bright in the far-infrared are not common in this sample. The average derived AGN contribution in ULIRGs is {approx}35%-40%, ranging from {approx}15%-35% among 'cool' (f {sub 25}/f {sub 60} {<=} 0.2) optically classified H II-like and LINER ULIRGs to {approx}50 and {approx}75% among warm Seyfert 2 and Seyfert 1 ULIRGs, respectively. This number exceeds {approx}80% in PG QSOs. ULIRGs fall in one of three distinct AGN classes: (1) objects with small extinctions and large polycyclic aromatic hydrocarbon (PAH) equivalent widths are highly starburst-dominated; (2) systems with large extinctions and modest PAH equivalent widths have larger AGN contributions, but still tend to be starburst-dominated; and (3) ULIRGs with both small extinctions and small PAH equivalent widths host AGN that are at least as powerful as the starbursts. The AGN contributions in class 2 ULIRGs are more uncertain than in the other objects, and we cannot formally rule out the possibility that these objects represent a physically distinct type of ULIRGs. A morphological trend is seen along the sequence (1)-(2)-(3), in general agreement with the standard ULIRG-QSO evolution scenario and suggestive of a broad peak in extinction during the intermediate stages of merger evolution. However, the scatter in this sequence, including the presence of a significant number of AGN-dominated systems prior to coalescence and starburst-dominated but fully merged systems, implies that black

  7. The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783

    NASA Technical Reports Server (NTRS)

    Onken, Christopher A.; Peterson, Bradley M.

    2004-01-01

    Improved analysis of ultraviolet and optical monitoring data on the Seyfert 1 galaxy NGC 3783 provides evidence for the existence of a supermassive, (8.7 +/- 1.1) x 10(exp 6) solar mass, black hole in this galaxy. By using recalibrated spectra from the International Ultraviolet Explorer satellite and ground-based optical data, as well as refined techniques of reverberation mapping analysis, we have reduced the statistical uncertainties in the response of the emission lines to variations in the ionizing continuum. The different time lags in the emission-line responses indicate a stratification in the ionization structure of the broad-line region and are consistent with the virial relationship suggested by the analysis of similar active galaxies.

  8. Near-infrared long-slit spectra of Seyfert galaxies: gas excitation across the central kiloparsec

    NASA Astrophysics Data System (ADS)

    van der Laan, T. P. R.; Schinnerer, E.; Böker, T.; Armus, L.

    2013-12-01

    Context. The excitation of the gas phase of the interstellar medium can be driven by various mechanisms. In galaxies with an active nucleus, such as Seyfert galaxies, both radiative and mechanical energy from the central black hole, or the stars in the disk surrounding it may play a role. Aims: We investigate the relative importance and range of influence of the active galactic nucleus for the excitation of ionized and molecular gas in the central kiloparsec of its host galaxy. Methods: We present H- and K-band long-slit spectra for a sample of 21 nearby (D < 70 Mpc) Seyfert galaxies obtained with the NIRSPEC instrument on the Keck telescope. For each galaxy, we fit the nebular line emission, stellar continua, and warm molecular gas as a function of distance from the nucleus. Results: Our analysis does not reveal a clear difference between the nucleus proper and off-nuclear environment in terms of excitation mechanisms, suggesting that the influence of an AGN reaches far into the disk of the host galaxy. The radial variations in emission line ratios indicate that, while local mechanisms do affect the gas excitation, they are often averaged out when measuring over extended regions. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.Table 4 and Appendix A are available in electronic form at http://www.aanda.orgThe fully calibrated long-slit spectra and fitting are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/560/A99

  9. An X-Ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Chiang, James

    2002-06-01

    Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, & Ryde for the X-ray binary Cyg X-1 and later applied to Seyfert galaxies by Zdziarski, Lubiński, & Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum and, as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those that have been observed from these objects can, in principle, be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate that satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available from accretion, one can predict the spectral properties of the heretofore poorly measured hard X-ray continuum above ~50 keV in type 1 Seyfert galaxies. Conversely, forthcoming measurements of the hard X-ray continuum by more sensitive hard X-ray and soft γ-ray telescopes, such as those aboard the International Gamma-Ray Astrophysics Laboratory, in conjunction with simultaneous optical, UV, and soft X-ray monitoring, will allow the mass accretion rates to be directly constrained for these sources in the context of this model.

  10. Discovery of a deep Seyfert-2 galaxy at z = 0.222 behind NGC 300

    NASA Astrophysics Data System (ADS)

    Combi, J. A.; García, F.; Rodríguez, M. J.; Gamen, R.; Cellone, S. A.

    2016-08-01

    We report on the unveiling of the nature of the unidentified X-ray source 3XMM J005450.3-373849 as a Seyfert-2 galaxy located behind the spiral galaxy NGC 300 using Hubble Space Telescope data, new spectroscopic Gemini observations and available XMM-Newton and Chandra data. We show that the X-ray source is positionally coincident with an extended optical source, composed of a marginally resolved nucleus/bulge, surrounded by an elliptical disc-like feature and two symmetrical outer rings. The optical spectrum is typical of a Seyfert-2 galaxy redshifted to z = 0.222 ± 0.001, which confirms that the source is not physically related to NGC 300. At this redshift the source would be located at 909 ± 4 Mpc (comoving distance in the standard model). The X-ray spectra of the source are well fitted by an absorbed power-law model. By tying NH between the six available spectra, we found a variable index Γ running from ˜2 in 2000-2001 to 1.4-1.6 in the 2005-2014 period. Alternatively, by tying Γ, we found variable absorption columns of NH ˜ 0.34 × 10-22 cm-2 in 2000-2001, and 0.54-0.75 × 10-22 cm-2 in the 2005-2014 period. Although we cannot distinguish between a spectral or absorption origin, from the derived unabsorbed X-ray fluxes, we are able to assure the presence of long-term X-ray variability. Furthermore, the unabsorbed X-ray luminosities of 0.8-2 × 1043 erg s-1 derived in the X-ray band are in agreement with a weakly obscured Seyfert-2 AGN at z ≈ 0.22.

  11. An X-Ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Chiang, James; White, Nicholas E. (Technical Monitor)

    2002-01-01

    Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert. galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, and Ryde for the X-ray binary Cygnus X-1 and later applied to Seyfert galaxies by Zdziarski, Lubifiski, and Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum, and as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those which have been observed from these objects can, in principle, be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate which satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available from accretion, one can predict the spectral properties of the heretofore poorly measured hard X-ray continuum above approximately 50 keV in type 1 Seyfert galaxies. Conversely, forthcoming measurements of the hard X-ray continuum by more sensitive hard X-ray and soft gamma-ray telescopes, such as those aboard the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) in conjunction with simultaneous optical, UV, and soft X-ray monitoring, will allow the mass accretion rates to be directly constrained for these sources in the context of this model.

  12. Discovery of a deep Seyfert-2 galaxy at z = 0.222 behind NGC 300

    NASA Astrophysics Data System (ADS)

    Combi, J. A.; García, F.; Rodríguez, M. J.; Gamen, R.; Cellone, S. A.

    2016-04-01

    We report on the unveiling of the nature of the unidentified X-ray source 3XMM J005450.3-373849 as a Seyfert 2 galaxy located behind the spiral galaxy NGC 300 using Hubble Space Telescope data, new spectroscopic Gemini observations and available XMM-Newton and Chandra data. We show that the X-ray source is positionally coincident with an extended optical source, composed by a marginally resolved nucleus/bulge, surrounded by an elliptical disc-like feature and two symmetrical outer rings. The optical spectrum is typical of a Seyfert 2 galaxy redshifted to z = 0.222 ± 0.001, which confirms that the source is not physically related to NGC 300. At this redshift the source would be located at 909±4 Mpc (comoving distance in the standard model). The X-ray spectra of the source are well-fitted by an absorbed power-law model. By tying NH between the six available spectra, we found a variable index Γ running from ˜2 in 2000-2001 years, to 1.4-1.6 in the 2005-2014 period. Alternatively, by tying Γ, we found variable absorption columns of NH ˜ 0.34 × 10-22 cm-2 in 2000-2001 years, and 0.54 - 0.75 × 10-22 cm-2 in the 2005-2014 period. Although we cannot distinguish between an spectral or absorption origin, from the derived unabsorbed X-ray fluxes, we are able to assure the presence of long-term X-ray variability. Furthermore, the unabsorbed X-ray luminosities of 0.8 - 2 ×1043 erg s-1 derived in the X-ray band are in agreement with a weakly obscured Seyfert-2 AGN at z ≈ 0.22.

  13. Radio Continuum Variability and Molecular Gas Reservoirs in the Type-Transitioning Seyfert Galaxy Mrk 590

    NASA Astrophysics Data System (ADS)

    Koay, Jun Yi; Vestergaard, Marianne; Casasola, Viviana; Peterson, Bradley M.

    2015-08-01

    Sometime between 2006 and 2012, the broad Hβ emission line of Mrk 590, once classified as a bona-fide Seyfert 1 galaxy, has completely disappeared! The optical-UV continuum emission has decreased to the point where it can be fully accounted for by stellar population models of the host galaxy. As such, Mrk 590 would now be classified as a Seyfert 1.9 or 2 galaxy, which goes against the prevailing scheme of AGN classification and unification where the presence of broad emission lines depends only on source orientation. Similar decreases in X-ray and radio continuum fluxes show that the central engine of Mrk 590 may be turning off or transitioning into a radiatively inefficient mode of accretion. We discuss the origin of the compact, unresolved radio emission in Mrk 590 and the physics of its variability in relation to the variability observed at other wavelengths, based on archival radio data and new VLBI observations. We also present recent ALMA observations of the CO(3-2) spectral line and sub-mm continuum emission; these provide the strongest limits to date on the molecular gas mass in the central ~100 pc, plus reveal the gas distribution and kinematics in the central kpc, to determine if this intriguing AGN is indeed running out of fuel.

  14. Revealing the coronal properties of Seyfert galaxies with NuSTAR

    NASA Astrophysics Data System (ADS)

    Marinucci, A.; NuSTAR Team

    2014-07-01

    The Nuclear Spectroscopic Telescope Array, or NuSTAR, launched on June 13, 2012, is the first orbiting telescope to focus high energy X-ray light above 10 keV. Compared to the previous generation of coded aperture observatories, this change in technology provides NuSTAR with 10x sharper images and 100x improved sensitivity. We will present and discuss the key parameters describing the hot corona of AGN that have been recently measured, with unprecedented accuracy, in a number of Seyfert galaxies.

  15. The Mg II line profile in the Seyfert galaxy NGC 4151: A new outflowing component

    NASA Technical Reports Server (NTRS)

    Leech, Kieron J.; Penston, M. V.; Snijders, M. A. J.; Gull, T.

    1986-01-01

    The Mg II 2795, 2802A doublet in the Seyfert galaxy NGC 4151 was examined to search for velocity systems in absorption and emission. Evidence for a narrow, outflowing absorption system in Mg II having a velocity of +825 km/sec relative to the Sun, -165 km/sec relative to the systemic velocity of NGC 4151 is presented. This feature is not present in Ly alpha or C IV and possible explanations for this are considered. For the Mg II and C IV lines a model decomposition of the line profile is shown.

  16. The Mg II line profile in the Seyfert galaxy NGC 4151 - A new outflowing component

    NASA Technical Reports Server (NTRS)

    Leech, Kieron J.; Penston, M. V.; Snijders, M. A. J.; Gull, T. R.

    1987-01-01

    This paper examines the Mg II 2795-2802 A doublet in the Seyfert galaxy NGC 4151 at a higher resolution than has previously been used, searching for velocity systems in absorption and emission. Evidence is presented for a new, narrow, outflowing absorption system in Mg II having a velocity of 825 km/s relative to the sun, and -165 km/s relative to the systemic velocity of NGC 4151. This feature is not present in Ly-alpha or C IV and possible explanations for this are considered. For the Mg II and C IV lines, a model decomposition of the line profile is presented.

  17. Periodicity analysis of the radio light curve of the Seyfert galaxy III Zw 2

    NASA Astrophysics Data System (ADS)

    Li, H. Z.; Xie, G. Z.; Dai, H.; Chen, L. E.; Yi, T. F.; Tang, Y. K.; Bao, Y. Y.; Lü, L. Z.; Na, W. W.; Ren, J. Y.

    2010-02-01

    We have analyzed the radio light curves of the Seyfert galaxy III Zw 2 at 22 and 37 GHz taken from the database of Metsähovi Radio Observatory, and found evidence of quasi-periodic activity. The light curves show great activity, with very complicated non-sinusoidal variations. Period of Pobs = 5.14 ± 0.19 yr was consistently identified by three methods: the Jurkevich method, the power spectrum intensity estimation method and the discrete correlation function method. The variability period of about 5.14 yr in III Zw 2 is caused most likely by the helical motion of the jet.

  18. The line-emitting regions of the exceptional Seyfert galaxy Markarian 359

    SciTech Connect

    Veilleux, S. )

    1991-02-01

    The results of a kinematic study of the narrow- and broad-line regions in Mrk 359 are presented. The emission-line profiles between 4600 and 7500 A are used to derive the physical characteristics of the line-emitting gas. Many aspects of the emission-line profiles of Mrk 359 make this object an exceptional Seyfert galaxy: extremely small widths of both the forbidden lines and the broad component of the permitted lines, absence of profile substructure, large blueward asymmetry of the high-ionization forbidden lines despite the apparent absence of reddening in the narrow-line region. Various scenarios are proposed to explain these results. 65 refs.

  19. The Far-Infrared Energy Distributions of Seyfert and Starburst Galaxies in the Local Universe: Infrared Space Observatory Photometry of the 12 Micron Active Galaxy Sample

    NASA Astrophysics Data System (ADS)

    Spinoglio, Luigi; Andreani, Paola; Malkan, Matthew A.

    2002-06-01

    New far-infrared photometry with ISOPHOT aboard the Infrared Space Observatory (ISO) is presented for 58 galaxies with homogeneous published data for another 32 galaxies, all belonging to the 12 μm galaxy sample-in total, 29 Seyfert 1 galaxies, 35 Seyfert 2 galaxies, and 12 starburst galaxies, or about half of the 12 μm active galaxy sample, plus 14 normal galaxies for comparison. ISO and Infrared Astronomical Satellite (IRAS) data are used to define color-color diagrams and spectral energy distributions (SEDs). Thermal dust emission at two temperatures (one cold at 15-30 K and one warm at 50-70 K) can fit the 60-200 μm SED, with a dust emissivity law proportional to the inverse square of the wavelength. Seyfert 1 galaxies and Seyfert 2 galaxies are indistinguishable longward of 100 μm, while, as already seen by IRAS, the former have flatter SEDs shortward of 60 μm. A mild anticorrelation is found between the [200-100] color and the ``60 μm excess.'' We infer that this is due to the fact that galaxies with a strong starburst component and thus a strong 60 μm flux have a steeper far-infrared turnover. In non-Seyfert galaxies, increasing the luminosity corresponds to increasing the star formation rate, which enhances the 25 and 60 μm emission. This shifts the peak emission from around 150 μm in the most quiescent spirals to shorter than 60 μm in the strongest starburst galaxies. To quantify these trends further, we identified with the IRAS colors three idealized infrared SEDs: pure quiescent disk emission, pure starburst emission, and pure Seyfert nucleus emission. Even between 100 and 200 μm, the quiescent disk emission remains much cooler than the starburst component. Seyfert galaxies have 100-200 μm SEDs ranging from pure disks to pure starbursts, with no apparent contribution from their active nuclei at those wavelengths. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France

  20. Variability Studies of Narrow Line Seyfert 1 Galaxy

    NASA Technical Reports Server (NTRS)

    Marshall, Hermann

    1994-01-01

    I supported the data reduction and analysis. We found that the source was not as variable as other soft AGN such as the narrow line Sy 1 galaxies (NLSls). The NLSls vary on time scales of days, while the ROSAT data for this target was fairly constant over a week at a time. Thus, it was very important to have a light curve that spanned 60 days as was the case for these ROSAT observations because the power spectral distribution can be established to very low frequencies that are rarely measured.

  1. The nuclear and integrated far-infrared emission of nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    García-González, J.; Alonso-Herrero, A.; Hernán-Caballero, A.; Pereira-Santaella, M.; Ramos-Almeida, C.; Acosta-Pulido, J. A.; Díaz-Santos, T.; Esquej, P.; González-Martín, O.; Ichikawa, K.; López-Rodríguez, E.; Povic, M.; Roche, P. F.; Sánchez-Portal, M.

    2016-06-01

    We present far-infrared (FIR) 70-500 μm imaging observations obtained with Herschel/Photodetector Array Camera (PACS) and Spectral and Photometric Imaging REceiver (SPIRE) of 33 nearby (median distance of 30 Mpc) Seyfert galaxies from the Revised Shapley-Ames (RSA) catalogue. We obtain the FIR nuclear (r = 1 kpc and r = 2 kpc) and integrated spectral energy distributions (SEDs). We estimate the unresolved nuclear emission at 70 μm and we fit the nuclear and integrated FIR SEDs with a grey body model. We find that the integrated FIR emission of the RSA Seyferts in our sample is dominated by emission from the host galaxy, with dust properties similar to those of normal galaxies (non-AGN). We use four criteria to select galaxies whose nuclear 70 μm emission has a significant AGN contribution: (1) elevated 70/160 μm flux ratios, (2) spatially resolved, high dust temperature gradient, (3) 70 μm excess emission with respect to the fit of the FIR SEDs with a grey body, and (4) excess of nuclear SFR obtained from 70 μm over SFR from mid-infrared indicators. 16 galaxies (48 per cent of the initial sample) satisfy at least one of these conditions, whereas 10 satisfy half or more. After careful examination of these, we select six bona fide candidates (18 per cent of the initial sample) and estimate that ˜40-70 per cent of their nuclear (r = 1-2 kpc) 70 μm emission is contributed by dust heated by the AGN.

  2. SUPERMASSIVE BLACK HOLES, PSEUDOBULGES, AND THE NARROW-LINE SEYFERT 1 GALAXIES

    SciTech Connect

    Mathur, Smita; Peterson, Bradley M.; Fields, Dale; Grupe, Dirk E-mail: peterson@astronomy.ohio-state.edu E-mail: grupe@astro.psu.edu

    2012-08-01

    We present Hubble Space Telescope Advanced Camera for Surveys (ACS) observations of 10 galaxies that host narrow-line Seyfert 1 (NLS1) nuclei, believed to contain relatively smaller mass black holes accreting at high Eddington ratios. We deconvolve each ACS image into a nuclear point source (AGN), a bulge, and a disk, and fitted the bulge with a Sersic profile and the disk with an exponential profile. We find that at least five galaxies can be classified as having pseudobulges. All 10 galaxies lie below the M{sub BH}-L{sub bulge} relation, confirming earlier results. Their locus is similar to that occupied by pseudobulges. This leads us to conclude that the growth of BHs in NLS1s is governed by secular processes rather than merger driven. Active galaxies in pseudobulges point to an alternative track of black hole-galaxy co-evolution. Because of the intrinsic scatter in black hole mass-bulge properties scaling relations caused by a combination of factors such as the galaxy morphology, orientation, and redshift evolution, application of scaling relations to determine BH masses may not be as straightforward as has been hoped.

  3. VizieR Online Data Catalog: Tully-Fisher distances for Spitzer galaxies (Sorce+, 2014)

    NASA Astrophysics Data System (ADS)

    Sorce, J. G.; Tully, R. B.; Courtois, H. M.; Jarrett, T. H.; Neill, J. D.; Shaya, E. J.

    2015-04-01

    The post-basic calibrated data of the 1270 observed galaxies for the CFS programme are available at the Spitzer Heritage Archive. Every galaxy has been observed with the first channel of the IRAC instrument where a point spread function with a FWHM=1.66arcsec is sampled with 1.2arcsec/pixels. The field of view is 5.2x5.2arcmin2 which is adequate to include most galaxies beyond twice their diameter at the 25th isophote (mag/arcsec2) in the B band. (2 data files).

  4. Structure of the Seyfert 2 galaxy Mkn 955

    NASA Astrophysics Data System (ADS)

    Vennik, J.; Funes, J. G.; Rafanelli, P.; Richter, G. M.

    Structural components of the barred Sy 2 galaxy Mkn 955 have been studied using the B, R and Hα images, obtained at the Vatican Advanced Technology Telescope 1.8-m VATT, as well as the HST WFPC2 archival F606W image. The B-R colour index image reveals the presence of a blue (B-R = 1.20) circumnuclear (diameter ~ 5'', i. e. 3.4 kpc) starburst ring. The strong red bar (with the length of 28'', axis ratio b/a = 0.42, P.A. = 112o, B-R = 1.45) is possibly embedded in a (red) lens, which is delimited by a blue (B-R = 1.12) tilted inner ring (or inner spiral arms). The continuum subtracted Hα image reveals high star formaton (SF) intensity in and around the active center, and the modest level of SF distributed along the rim of the inner ring. The adaptive filtered broadband images reveal the presence of a faint distorted outer ring or outer spiral arms, which begin just outside the inner tilted ring and at the ends of the bar, and could mark past interactions. Several small galaxies are distributed in the vicinity of Mkn 955, with the most probable low-surface-brightness blue companion (BT = 18.8, B-R = 0.87) located 106'' to the west of Mkn 955. Light profiles along the bar major and minor axes have been extracted and the (unresolved) nucleus, bulge, exponential disk and bar + lens + ring components could have been distinguished on these profiles. The scale parameters of the individual components have been determined.

  5. High-Resolution Emission-Line Imaging of Seyfert Galaxies. II. Evidence for Anisotropic Ionizing Radiation

    NASA Astrophysics Data System (ADS)

    Wilson, Andrew S.; Ward, Martin J.; Haniff, Christopher A.

    1988-11-01

    In the preceding paper, we describe a direct imaging survey of Seyfert galaxies with "linear" radio structures and find that the major axes and spatial scales of the circumnuclear emission-line gas are very similar to those of the radio continuum sources. In the present paper, the nature of this close connection between thermal and relativistic gases is assessed in detail. Models in which the kinetic energy of the radio jets or plasmoids powers shock waves, which ionize the gas, seem energetically feasible but disagree with the off-nuclear line intensity ratios. Ionization by relativistic electrons is negligible, but they may contribute to the heating of the gas. We favor a scenario in which the radio jets and plasmoids shock, accelerate, and compress ambient and entrained gas, but the dominant source of ionization is the nonstellar nuclear ultraviolet continuum. This ultraviolet source appears to be partially beamed along the axis of the radio jet. Photoionization by ultraviolet synchrotron radiation generated via shocks in the ejecta may also contribute, especially in Seyfert 2 galaxies. A comparison between the number of ionizing photons, N_i_, inferred by extrapolation of the directly observed continuum, and the number of ionizing photons, N_Hβ_, required to generate the Hβ emission has been made for six galaxies in our sample. In at least two galaxies, we find N_i_ << N_Hβ_, suggesting that the gas is exposed to a higher ionizing flux than inferred from direct observations of the nucleus, and supporting the idea of partial beaming. Similarly, the energy in the continuum between 100 A and 1 micron, if emitted isotropically, is inadequate to fuel the thermal nuclear infrared sources, implying that the radiating dust is heated by a more luminous optical-ultraviolet source. We speculate that the nuclear infrared emission of Seyfert 2 galaxies arises from dust in molecular clouds exposed to the partially beamed radiation, and we predict that the 10 micron

  6. Relativistic Fe Kα line study in Seyfert 1 galaxies observed with Suzaku

    NASA Astrophysics Data System (ADS)

    Mantovani, G.; Nandra, K.; Ponti, G.

    2016-06-01

    We present an analysis of a sample of Seyfert 1 galaxies observed with Suzaku. The aim of this work is to examine critically the evidence for a relativistic Fe Kα line in the X-ray spectra of these active galactic nuclei. The sample was compiled from those sources in which a relativistic component was missing in at least one XMM-Newton observation. We analysed the Suzaku spectra of these objects in order to have more constraints on the high-energy emission, including the Compton reflection hump. The results show that the relativistic Fe Kα line is detected (at >95 per cent confidence) in all sources observed with high-signal-to-noise ratio (e.g. where the counts in the 5-7 keV energy band are ≳4 × 104). This is in agreement with the idea that relativistic lines are a ubiquitous feature in the spectra of Seyfert galaxies, but are often difficult to detect without very high-quality data. We also investigate the relation between the Fe Kα line and the reflection continuum at high energies. For most of the sample, the strength of the reflection component is consistent with that of the line. There are exceptions in both senses, however i.e. where the reflection continuum is strong but with weak line emission, and vice versa. These observations present a challenge for standard reflection models.

  7. Thick discs, and an outflow, of dense gas in the nuclei of nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Yi; Davies, R. I.; Burtscher, L.; Contursi, A.; Genzel, R.; González-Alfonso, E.; Graciá-Carpio, J.; Janssen, A.; Lutz, D.; Orban de Xivry, G.; Rosario, D.; Schnorr-Müller, A.; Sternberg, A.; Sturm, E.; Tacconi, L.

    2016-05-01

    We discuss the dense molecular gas in central regions of nearby Seyfert galaxies, and report new arcsec resolution observations of HCN (1-0) and HCO+ (1-0) for three objects. In NGC 3079, the lines show complex profiles as a result of self-absorption and saturated continuum absorption. H13CN reveals the continuum absorption profile, with a peak close to the galaxy's systemic velocity that traces disc rotation, and a second feature with a blue wing extending to -350 km s-1 that most likely traces a nuclear outflow. The morphological and spectral properties of the emission lines allow us to constrain the dense gas dynamics. We combine our kinematic analysis for these three objects, as well as another with archival data, with a previous comparable analysis of four other objects, to create a sample of eight Seyferts. In seven of these, the emission line kinematics imply thick disc structures on radial scales of ˜100 pc, suggesting such structures are a common occurrence. We find a relation between the circum-nuclear LHCN and Mdyn that can be explained by a gas fraction of 10 per cent and a conversion factor αHCN ˜ 10 between gas mass and HCN luminosity. Finally, adopting a different perspective to probe the physical properties of the gas around active galactic nuclei, we report on an analysis of molecular line ratios which indicates that the clouds in this region are not self-gravitating.

  8. Radio-loud narrow-line Seyfert 1 galaxies with high-velocity outflows

    NASA Astrophysics Data System (ADS)

    Komossa, S.; Xu, D.; Zensus, J. A.

    2016-02-01

    We have studied four radio-loud Narrow-line Seyfert 1 (NLS1) galaxies with extreme optical emission-line shifts, indicating radial outflow velocities of up 2450 km s-1. The shifts are accompanied by strong line broadening, up to 2270 km s-1 in [NeV]. A significant ionization stratification (higher line shift at higher ionization potential) of most ions implies that we see a large-scale wind rather than single, localized jet-cloud interactions. The observations are consistent with a scenario, where the signatures of outflows are maximized because of a pole-on view into the central engine of these radio-loud NLS1 galaxies.

  9. Near-infrared spectrophotometry of four Seyfert 1 galaxies and NGC 1275

    NASA Technical Reports Server (NTRS)

    Rudy, R. J.; Jones, B.; Levan, P. D.; Puetter, R. C.; Smith, H. E.; Willner, S. P.; Tokunaga, A. T.

    1982-01-01

    Low-resolution spectrophotometry from 2 to 4 microns is reported for the four Seyfert 1 galaxies Mrk 335, 3C 120, Mrk 509, NGC 7469, and the peculiar emission-line galaxy NGC 1275. The spectrum of NGC 7469 exhibits a strong 3.3-micron dust feature, indicating a thermal origin for the bulk of its considerable nonstellar infrared emission. NGC 1275 has a large stellar contribution to its infrared flux at wavelengths shortward of 3 microns. The spectrum from 3 to 4 microns fits a power law which fits the 10-micron and 20-micron broad bands, as well. A thermal model which can explain the spectrum of NGC 1275 is discussed. Mrk 335 displays a complex spectrum suggestive of thermal dust emission. 3C 120 and Mrk 509 have nonstellar infrared emission shortward of 2 microns, but the data are ambiguous as to whether this emission is thermal or nonthermal in origin.

  10. Optical monitoring observations of two γ-ray narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Liu, Hao; Wu, Chao; Wang, Jing; Wei, Jianyan

    2016-04-01

    1H 0323+342 is a rather radio-loud narrow-line Seyfert 1 galaxy (NLS1) with γ-ray emission. Optical observations were carried out in B and R bands which covered 6 nights in 2011 to obtain light curves of 1H 0323+342. The difference image subtraction method was used to deal with the data of 1H 0323+342 because of the existence of extended host galaxy. Optical variability on day timescale was reported here. We also monitored the first γ-ray NLS1 SDSS J094857.3+002225 and confirmed the existence of intranight optical variability (INOV). These indicated the existence of a relativistic jet in these NLS1s.

  11. Line profiles and the kinematics of the narrow-line region in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    De Robertis, M. M.; Shaw, Richard A.

    1990-01-01

    High signal-to-noise ratio and long-slit CCD spectra at about 100 km/sec resolution have been obtained for six high-ionization Seyfert galaxies. By subtracting the stellar absorption features with the aid of continuum templates, and using deblending techniques, the asymmetry indices of a number of optical emission-line profiles were measured, spanning a wide range in both ionization potential and critical density in each galaxy. The fundamental problem of the cloud-motion direction in the narrow-line region (NLR) has been studied, using these measurements and on the assumption that the preponderance of blueward profile asymmetries requires radial motion as well as a source of extinction. Simple and spherically symmetric NLR simulations are performed to demonstrate that infall and outflow models can be distinguished by comparing asymmetry indices as a function of ionization potential and critical density.

  12. Optical polarization of the Seyfert galaxies IC 4329A and MRK 376

    NASA Technical Reports Server (NTRS)

    Martin, P. G.; Stockman, H. S.; Angel, J. R. P.; Maza, J.; Beaver, E. A.

    1982-01-01

    Measurements of the optical polarizations of the two highly polarized Seyfert 1 galaxies IC 4329A and Mrk 376 are presented. Continuum and line polarization of the two objects were observed with the Steward Observatory 2.25-m telescope using a two-channel photoelectric Pockels cell polarimeter, a single-channel scanner, and a digicon attached to a flint prism spectrograph. Results indicate that, for both galaxies, the emission line polarization and underlying continuum polarization are identical, rising toward short wavelengths, and therefore must be explained by a common mechanism. Such a mechanism is suggested to involve polarization produced by aligned grains in the galactic disk. A model for polarization in IC 4329A by this mechanism predicts a grain size three times smaller than Galactic polarizing grains, as well as a visual extinction of about 2 magnitudes, a gas to dust mass ratio close to 100 and a polarization to extinction ratio comparable to the Galactic ratio.

  13. The complex nature of the Seyfert galaxy NGC 7592

    NASA Technical Reports Server (NTRS)

    Rafanelli, Piero; Marziani, Paolo

    1990-01-01

    Long slit spectra of NGC 7592 were taken on Sep. 26 to 30, 1989 at the 1.52 cm European Southern Observatory (ESO) telescope, equipped with a Boller and Chivens spectrograph and an RCA High Resolution charge coupled device (CCD) camera. The problem of the nature of Region C is addressed at first. C shows an heliocentric radial velocity very similar to that of Regions A and B. Moreover, the arm departing from C is most probably a tidal tail, because its extension is large and its orientation is peculiar. The high H alpha luminosity of C is typical of a starburst nucleus. These facts argue in favor of C being the nucleus of a third galactic component (southern component S) physically interacting with the SE component of NGC 7592. The directions of the velocity vectors in various regions of NGC 7592 are marked. It is noteworthy that the SE component rotates clockwise, if the radial velocity difference delta v sub r from its nucleus B is due to rotation. Under the same assumption for the delta v sub r = v sub r-v sub r, A, the NW component seems to rotate counterclockwise. Thus, the gas in the regions where the two galactic bodies are in contact moves in the same way, suggesting that a prograde encounter is occurring. It is known (e.g., Toomre and Toomre, 1972) that prograde encounters have the most disruptive effects on the interacting galaxies, leading to the formation of tidal tails. The interpretation of the wing of the NW component in terms of a tidal tail thus appears very likely. A similar situation holds for the interaction between SE and S too, where S rotates counterclockwise. The interpretation of the arm departing from C as a tidal tail is supported also in this case. The difference in radial velocity between A and B (delta v sub r approx. equal - 40 km s(exp-1)) and the morphology of NGC 7592 suggests that the NW component is beyond the SE one and is approaching it. The most heavily reddened regions (E(B - V) approx. equals 0.7, derived from the H alpha

  14. Integral Observations of the Reflection Component of Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Fabian, Andrew

    2005-01-01

    The data were analyzed by Dr. Fabian's student Adrian Turner and included in his thesis (completed Sept 2004). We did not detect MCG-6 using the then current software and the spectrum of the Circinus galaxy turned out to be even worse then the published BeppoSAX spectrum. We decided not to do any more work on it. We were contacted about the data in March by Thierry Courvoisier (the data were thea public) as he had a student, Simona Soidi, working on a compilation of spectra. Dr. Fabian sent them the chapter from Adrian's thesis and we provided some general comments on what they were doing on 6 objects. This has since been accepted for publication with Fabian as a co-author. A paper on the Integral AGN catalogue appeared on astro-ph a few days ago which contains an detection of MCG-6 with a very poor spectrum. We didn't detect it because the software back then required a source to be detected within something like 30 min exposure in order to work. Integral is NOT very sensitive.

  15. Parsec-scale jets and tori in seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Roy, A. L.; Wrobel, J. M.; Wilson, A. S.; Ulvestad, J. S.; Norris, R. P.; Mundell, C. G.; Krichbaum, T. P.; Falcke, H.; Colbert, E. J. M.

    2001-01-01

    H. Falcke, T.P. Krichbaum, C.G. Mundell, J.S. Ulvestad, A.S. Wilson, J.M. Wrobel Active galaxies tend to be powerful or weak radio sources, and we still do not understand the underlying cause. Perhaps the engine is the same in both systems and the jet gets disrupted by dense interstellar medium in radio-quiet objects, or else the difference is intrinsic with jet power scaling with black hole spin. To distinguish, one can look for signs of interaction between the jet and the narrow-line region, and to measure the jet speed close to the jet base, before environmental effects become important. We find one-sided parsec-scale jet structures in Mrk 348, Mrk 231, NGC 4151, and NGC 5506 using VLBI, and we measure low jet speeds (typically <= 0.25 c). The one-sidedness probably is not due to Doppler boosting, but rather is probably free-free absorption. Plasma conditions required to produce the absorption are Ne >= 2 × 105 cm-3 assuming a path length of 0.1 pc, typical of that expected at the inner edge of the obscuring torus.

  16. Probing the Absorption Structures in Seyfert Galaxies with X-ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gelbord, J.

    2001-12-01

    The paradigm of the unified model for Seyfert galaxies has had many successes in explaining the range of phenomena observed in active galaxies. However, the structures invoked in this scenario have been difficult to observe due to their limited sizes and due to contaminating flux from other regions. As a result, some of these structures, notably the putative obscuring torus, are poorly constrained. The difficulty in isolating the emission from the central regions can be mitigated (but not eliminated!) by focusing upon high-energy radiation, which is dominated by direct and reprocessed radiation from the nuclear region. We have drawn upon the large number of X-ray spectra available in the ASCA archive in order to study the distribution of properties in a large sample of high-energy observations. Furthermore, by uniformly processing the data ourselves, we minimize systematic effects. One asset of X-rays is that they provide a sensitive probe of absorbers in the line of sight toward the central region, because photoelectric absorption cuts off the continuum at low energies. In the ASCA bandpass column densities of ~1021-23 cm-2 can be measured. This is an interesting range of densities because it allows us to distinguish between absorption in a torus or possibly a warped accretion disk (where column densities are expected to be high) and absorption taking place at larger scales in the host galaxy (where column densities are expected to be closer to Galactic values of 1020-21 cm-2). This data is then compared to data from other wavebands. Published radio studies (e.g.: Nagar & Wilson 1999, Kinney et al. 2000) have put constraints on the orientations of the accretion systems in Seyfert galaxies. We combine these and the X-ray measurements for the ~50 sources in these studies which have ASCA data in order to constrain the various possible absorption structures and test the unification scenario.

  17. 3D spectroscopy of merger Seyfert galaxy Mrk 334: nuclear starburst, superwind and the circumnuclear cavern

    NASA Astrophysics Data System (ADS)

    Smirnova, Aleksandrina; Moiseev, Alexei

    2010-01-01

    We are presenting new results on kinematics and structure of the Mrk 334 Seyfert galaxy. Panoramic (3D) spectroscopy is performed at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences using the integral-field Multi-Pupil Fiber Spectrograph (MPFS) and scanning Fabry-Pérot interferometer. The deep images have revealed that Mrk 334 is observed during the final stage of its merging with a massive companion. A possible mass ratio ranges from 1/5 to 1/3. The merger has triggered mass redistribution in the disc resulting in an intensification of nuclear activity and in a burst of star formation in the inner region of the galaxy. The circumnuclear starburst is so intense that its contribution to the gas ionization exceeds that contribution of the active galactic nuclei (AGN). We interpret the nuclear gas outflow with velocities of ~200kms-1 as a galactic superwind that accompanies the violent star formation. This suggestion is consistent with the asymmetric X-ray brightness distribution in Mrk 334. The trajectory of the fragments of the disrupted satellite in the vicinity of the main galaxy nucleus can be traced. In the galaxy disc, a cavern is found that is filled with a low-density ionized gas. We consider this region to be the place where the remnants of the companion have recently penetrated through the gaseous disc of the main galaxy.

  18. Detection of CO(1 to 0) emission from infrared quasars and luminous Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Sanders, D. B.; Scoville, N. Z.; Zensus, A.; Soifer, B. T.; Wilson, T. L.

    1989-01-01

    CO(1 to 0) emission has been detected from the infrared quasar IRAS 07598+6508 and the luminous Seyfert galaxies IRAS 08572+3915 and Markarian 463 with the IRAM 30-m telescope. These objects were selected from a complete list of warm ultraluminous IRAS sources. The maximum redshift observed was 0.149 (cz = 44.621 km/s , IRAS 07598+6508). Assuming the same empirical relationship between CO brightness and H2 surface mass density as has been found for giant molecular clouds in the Milky Way, the mass of H2 gas in these objects is in the range 0.7 - 6 x 10 to the 10th solar masses, more than 2 - 20 times the H2 content of the Galaxy. The infrared and molecular gas properties of these galaxies are similar to other 'warm' ultraluminous infrared galaxies such as Mrk 231, and the UV-excess quasar Mrk 1014. It is suggested that objects such as these represent an important link in the evolution of ultraluminous infrared galaxies into UV-excess quasars.

  19. Radio Jets Clearing the Way Through a Galaxy: Watching Feedback in Action in the Seyfert Galaxy IC 5063

    NASA Astrophysics Data System (ADS)

    Morganti, R.; Oosterloo, T. A.; Oonk, J. B. R.; Frieswijk, W.; Tadhunter, C. N.

    2015-12-01

    High-resolution (0.5 arcsec) CO(2-1) observations performed with the Atacama Large Millimetre/submillimetre Array have been used to trace the kinematics of the molecular gas in the Seyfert 2 galaxy{IC 5063}. Although one of the most radio-loud Seyfert galaxy, IC 5063 is a relatively weak radio source (P1.4GHz=3 ×1023 W Hz-1). The data reveal that the kinematics of the gas is very complex. A fast outflow of molecular gas extends along the entire radio jet (˜ 1 kpc), with the highest outflow velocities about 0.5 kpc from the nucleus, at the location of the brighter hot-spot in the W lobe. All the observed characteristics can be described by a scenario of a radio plasma jet expanding into a clumpy medium, interacting directly with the clouds and inflating a cocoon that drives a lateral outflow into the interstellar medium. This suggests that most of the observed cold molecular outflow is due to fast cooling of the gas after the passage of a shock and that it is the end product of the cooling process.

  20. Simultaneous Ultraviolet Line and Continuum Variability Studies in Seyfert 1 Galaxies and Quasars

    NASA Astrophysics Data System (ADS)

    Honnappa, Vijayakumar; Prabhakar, Vedavvathi

    Simultaneous Ultraviolet Line and Continuum Variability Studies in Seyfert 1 Galaxies and Quasars Vijayakumar H. Doddamani*and P. Vedavathi Department of Physics, Bangalore University, Bangalore-560056, *Corresponding author:drvkdmani@gmail.com, Abstract The line and continuum flux variability is a hallmark phenomenon of Seyfert 1 galaxies and quasars. Large amplitude luminosity variability is observed in AGNs from x-rays through radio waves over a wide-ranging timescales from minutes to years. The combinations of high luminosity and short variability time scales suggests, that the power of AGN is produced by a phenomena more efficient in terms of energy release per unit mass than ordinary stellar processes. The basic structure of AGNs thus developed based on the variability studies consists of a central super massive black hole surrounded by an accretion disk or more generally optically thick plasma radiating brightly at UV and soft X-ray wavelengths. The variability studies have been important tools of understanding the physics of the central regions of AGNs, which in general cannot be resolved with the existing or planned ground and space telescopes. Therefore, we have undertaken a study of the simultaneous ultraviolet line and continuum flux variability studies in MRK501, ESOB113-IG45 (also called as Fairall 9), MRK1506, MRK1095 V*GQCOM, PG1211+143, MRK205, PG1226+023 (also known as 3C273), PG1351+640, MRK 1383, MRK876 and QSO2251-178 as these objects have been repeatedly observed by IUE satellite over several years.. It is observed that Fairall 9, MRK 1095 and 3C273 exhibit the large amplitude variability (» 30 times) over the observed timescale, which spans several years. The remaining nine objects exhibit small amplitude (» 5 times) variability over the long time scale of observations. The highest amplitude variability is observed in Lya with a least in the MgII line. The amplitude of variability decreases in the order of Lya, CIV and Mg II, lines. These

  1. Near-Infrared Coronal Lines in Narrow-Line Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Rodríguez-Ardila, A.; Viegas, S. M.; Pastoriza, M. G.; Prato, L.

    2002-11-01

    We report spectroscopic observations in the wavelength region 0.8-2.4 μm aimed at detecting near-infrared coronal lines in a sample of five narrow-line and one broad-line Seyfert 1 galaxies. Our measurements show that [Si VI] 1.963 μm, [S IX] 1.252 μm, and [S VIII] 0.991 μm are present in most of the objects and are useful tracers of nuclear activity. Line ratios between coronal and low-ionization forbidden lines are larger in narrow-line Seyfert 1 galaxies. A positive correlation between FHWM and ionization potential of the forbidden lines is observed. Some coronal lines have widths similar to those of lines emitted in the broad-line region (BLR), indicating that part of their flux originates in gas close to the outer portions of the BLR. Most coronal lines are blueshifted relative to the systemic velocity of the galaxy, and this shift increases with the increase in line width. Asymmetries toward the blue are observed in the profiles of high-ionization Fe lines, suggesting that the emitting gas is related to winds or outflows, most probably originating in material that is being evaporated from the torus. This scenario is supported by models that combine the effects of shock ionization and photoionization by a central continuum source in the gas clouds. The agreement between the coronal line emission predicted by the models and the observations is satisfactory; the models reproduced the whole range of coronal line intensities observed. We also report the detection of [Fe XIII] 1.074, 1.079 μm in three of our objects and the first detection of [P II] 1.188 μm and [Ni II] 1.191 μm in a Seyfert 1 galaxy, Ark 564. Using the ratio [P II]/[Fe II], we deduced that most Fe present in the outer narrow-line region of Ark 564 is locked up in grains and that the influence of shocks is negligible.

  2. X-ray spectral survey with XMM-Newton of a complete sample of nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Cappi, M.; Panessa, F.; Bassani, L.; Dadina, M.; Di Cocco, G.; Comastri, A.; della Ceca, R.; Filippenko, A. V.; Gianotti, F.; Ho, L. C.; Malaguti, G.; Mulchaey, J. S.; Palumbo, G. G. C.; Piconcelli, E.; Sargent, W. L. W.; Stephen, J.; Trifoglio, M.; Weaver, K. A.

    2006-02-01

    Results obtained from an X-ray spectral survey of nearby Seyfert galaxies using XMM-Newton are reported. The sample was optically selected, well defined, complete in B magnitude, and distance limited: it consists of the nearest (D ⪉22 Mpc) 27 Seyfert galaxies (9 of type 1, 18 of type 2) taken from the Ho et al. (1997a, ApJS, 112, 315) sample. This is one of the largest atlases of hard X-ray spectra of low-luminosity active galaxies ever assembled. All nuclear sources except two Seyfert 2s are detected between 2 and 10 keV, half for the first time ever, and average spectra are obtained for all of them. Nuclear luminosities reach values down to 1038 erg s-1. The shape of the distribution of X-ray parameters is affected by the presence of Compton-thick objects (⪆30% among type 2s). The latter have been identified either directly from their intense FeK line and flat X-ray spectra, or indirectly with flux diagnostic diagrams which use isotropic indicators. After taking into account these highly absorbed sources, we find that (i) the intrinsic X-ray spectral properties (i.e., spectral shapes and luminosities above 2 keV) are consistent between type 1 and type 2 Seyferts, as expected from "unified models"; (ii) Seyfert galaxies as a whole are distributed fairly continuously over the entire range of N_H, between 1020 and 1025 cm-2; and (iii) while Seyfert 1s tend to have lower NH and Seyfert 2s tend to have the highest, we find 30% and 10% exceptions, respectively. Overall the sample is of sufficient quality to well represent the average intrinsic X-ray spectral properties of nearby active galactic nuclei, including a proper estimate of the distribution of their absorbing columns. Finally, we conclude that, with the exception of a few cases, the present study agrees with predictions of unified models of Seyfert galaxies, and extends their validity down to very low luminosities.

  3. The Spitzer Interacting Galaxies Survey: A Mid-infrared Atlas of Star Formation

    NASA Astrophysics Data System (ADS)

    Brassington, N. J.; Zezas, A.; Ashby, M. L. N.; Lanz, L.; Smith, Howard. A.; Willner, S. P.; Klein, C.

    2015-05-01

    The Spitzer Interacting Galaxies Survey is a sample of 103 nearby galaxies in 48 systems, selected using association likelihoods and therefore free from disturbed morphology biases. All galaxies have been observed with Infrared Array Camera and MIPS 24 μm bands from the Spitzer Space Telescope. This catalog presents the global flux densities and colors of all systems and correlations between the interacting systems and their specific star formation rate (sSFR). This sample contains a wide variety of galaxy interactions with systems ranging in mass, mass ratios, and gas-content as well as interaction strength. This study seeks to identify the process of triggering star formation in galaxy interactions, therefore, we focus on the non-active galactic nucleus spiral galaxies only. From this subset of 70 spiral galaxies we have determined that this sample has enhanced sSFR compared to a sample of non-interacting field galaxies. Through optical data we have classified each system by “interaction strength” the strongly interacting (Stage 4) galaxies have higher sSFR values than the weakly (Stage 2) and moderately (Stage 3) interacting systems. However, the Stage 2 and 3 systems have statistically identical sSFR properties, despite the lack of optical interaction signatures exhibited by the Stage 2 galaxies. We suggest that the similarity of sSFR in these stages could be a consequence of some of these Stage 2 systems actually being post-perigalactic and having had sufficient time for their tidal features to fade to undetectable levels. This interpretation is consistent with the correlation of sSFR with separation, which we have determined to have little variation up to 100 kpc.

  4. EXTENDED NARROW-LINE EMISSION IN THE BRIGHT SEYFERT 1.5 GALAXY HE 2211-3903

    SciTech Connect

    Scharwaechter, J.; Dopita, M. A.; Zuther, J.; Fischer, S.; Eckart, A.; Komossa, S.

    2011-08-15

    Extended narrow-line regions (ENLRs) and extended emission-line regions have been the focus of integral field spectroscopy aiming at the inner kiloparsecs of nearby Seyfert galaxies as well as the larger environment of high-redshift QSOs. Based on observations with the Wide Field Spectrograph at the 2.3 m telescope of the Australian National University, we present spatially resolved emission-line diagnostics of the bright Seyfert 1.5 galaxy HE 2211-3903 which is drawn from a sample of the brightest Seyfert galaxies at z < 0.06 with luminosities around the classical Seyfert/QSO demarcation. In addition to the previously known spiral arms of HE 2211-3903, the emission-line maps reveal a large-scale ring with a radius of about 6 kpc which is connected to the active galactic nucleus (AGN) through a bar-like structure. The overall gas kinematics indicates a disk rotation pattern. The emission-line ratios show Seyfert-type, H II region-type, and composite classifications, while there is no strong evidence of LINER-type ratios. Shock ionization is likely to be negligible throughout the galaxy. The composite line ratios are explained via a mixing line between AGN and H II region photoionization. Composite line ratios are predominantly found in between the H II regions in the circum-nuclear region, the bar-like structure to the east of the nucleus, and the eastern half of the ring, suggesting AGN photoionization of the low-density interstellar medium in an ENLR on galaxy scales. The line ratios in the nucleus indicate N enrichment, which is discussed in terms of chemical enrichment by Wolf-Rayet and asymptotic giant branch stars during past and ongoing nuclear starburst activity.

  5. The Keck OSIRIS Nearby AGN Survey: The Nuclear Gas and Stellar Structure in the Central 200 pc of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Hicks, E.

    2015-09-01

    We present the first results from the KONA (Keck OSIRIS Nearby AGN) survey, which used the integral field unit OSIRIS plus adaptive optics to probe down to scales of 5-10 parsecs in a sample of 40 Seyfert galaxies. With these K-band data we measure the two-dimensional distribution and kinematics of the nuclear stars, molecular gas, and ionized gas within the central few hundred parsecs. In the majority of the galaxies the molecular gas, traced by 1-0 S(1) H2, is in circular rotation in a geometrically thick disk that is co- spatial with the stellar disk inferred from the stellar kinematics. A significant fraction of the Seyferts exhibit kinematic signatures of inflow and/or outflow in the molecular gas that is superimposed on this disk rotation. The ionized gas in most galaxies shows evidence of outflows, and, in many cases, is interacting with the interstellar medium traced by the molecular gas. The sample consists of both type 1 and type 2 Seyferts, allowing for a statistical comparison of the nuclear stellar and gas properties in the subsamples and the identification of significant contributors to possible orientation effects. Differences in the prevalence of the primary fueling mechanisms inferred from the gas kinematics in the type 1 and 2 subsamples, as well as evolution of the nuclear properties with AGN luminosity, are investigated. The nuclear regions of Seyfert 2s known to have a hidden broadline region are also compared with the Seyfert 1s and non-HBLR Seyfert 2s, including characterization of the stellar population via spectral fitting.

  6. A JET MODEL FOR THE BROADBAND SPECTRUM OF THE SEYFERT 1 GALAXY NGC 4051

    SciTech Connect

    Maitra, Dipankar; Miller, Jon M.; King, Ashley; Markoff, Sera

    2011-07-10

    Recent radio very long baseline interferometry observations of the {approx} parsec-scale nuclear region of the narrow line Seyfert 1 galaxy NGC 4051 hint toward the presence of outflowing plasma. From available literature we have collected high-quality, high-resolution broadband spectral energy distribution (SED) data of the nuclear region of NGC 4051 spanning from radio through X-rays, to test whether the broadband SED can be explained within the framework of a relativistically outflowing jet model. We show that once the contribution from the host galaxy is taken into account, the broadband emission from the active galactic nucleus (AGN) of NGC 4051 can be well described by the jet model. Contributions from dust and ongoing star formation in the nuclear region tend to dominate the IR emission even at the highest resolutions. In the framework of the jet model, the correlated high variability of the extreme-ultraviolet and X-rays compared to other wavelengths suggests that the emission at these wavelengths is optically thin synchrotron originating in the particle acceleration site(s) in the jet very close (few r{sub g}= GM{sub BH}/c{sup 2}) to the central supermassive black hole of mass M{sub BH}. Our conclusions support the hypothesis that narrow line Seyfert 1 galaxies (which NGC 4051 is a member of) harbor a 'jetted' outflow with properties similar to what has already been seen in low-luminosity AGNs and stellar mass black holes in hard X-ray state.

  7. A Hubble Space Telescope Survey of Extended [O III] λ5007 Emission in a Far-Infrared Selected Sample of Seyfert Galaxies: Observations

    NASA Astrophysics Data System (ADS)

    Schmitt, H. R.; Donley, J. L.; Antonucci, R. R. J.; Hutchings, J. B.; Kinney, A. L.

    2003-10-01

    We present a Hubble Space Telescope (HST) survey of extended [O III] emission for a sample of 60 Seyfert galaxies (22 Seyfert 1 galaxies and 38 Seyfert 2 galaxies), selected based on their far-infrared properties. The observations for 42 of these galaxies were done in a snapshot survey with WFPC2. The remaining 18 were obtained from the HST archive, most of which were observed with the same configuration. These observations cover 68% of the objects in the sample defined by Kinney et al. and create a valuable data set for the study of the narrow-line region (NLR) properties of Seyfert galaxies. In this paper, we present the details of the observations, reductions, and measurements. We also discuss the extended structure of individual sources, and the relation of this emission to the radio and host galaxy morphology. We also address how representative the subsample of [O III]-imaged galaxies is of the entire sample, and possible selection effects that may affect this comparison of the properties of Seyfert 1 and Seyfert 2 galaxies. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  8. The nuclear and extended mid-infrared emission of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    García-Bernete, I.; Ramos Almeida, C.; Acosta-Pulido, J. A.; Alonso-Herrero, A.; González-Martín, O.; Hernán-Caballero, A.; Pereira-Santaella, M.; Levenson, N. A.; Packham, C.; Perlman, E. S.; Ichikawa, K.; Esquej, P.; Díaz-Santos, T.

    2016-08-01

    We present subarcsecond resolution mid-infrared (MIR) images obtained with 8-10 m-class ground-based telescopes of a complete volume-limited (DL <40 Mpc) sample of 24 Seyfert galaxies selected from the Swift/BAT nine month catalog. We use those MIR images to study the nuclear and circumnuclear emission of the galaxies. Using different methods to classify the MIR morphologies on scales of ˜400 pc, we find that the majority of the galaxies (75-83%) are extended or possibly extended and 17-25% are point-like. This extended emission is compact and it has low surface brightness compared with the nuclear emission, and it represents, on average, ˜30% of the total MIR emission of the galaxies in the sample. We find that the galaxies whose circumnuclear MIR emission is dominated by star formation show more extended emission (650±700 pc) than AGN-dominated systems (300±100 pc). In general, the galaxies with point-like MIR morphologies are face-on or moderately inclined (b/a˜0.4-1.0), and we do not find significant differences between the morphologies of Sy1 and Sy2. We used the nuclear and circumnuclear fluxes to investigate their correlation with different AGN and SF activity indicators. We find that the nuclear MIR emission (the inner ˜70 pc) is strongly correlated with the X-ray emission (the harder the X-rays the better the correlation) and with the [O IV] λ25.89 μm emission line, indicating that it is AGN-dominated. We find the same results, although with more scatter, for the circumnuclear emission, which indicates that the AGN dominates the MIR emission in the inner ˜400 pc of the galaxies, with some contribution from star formation.

  9. An Expanded RXTE Survey of Long-Term X-ray Variability in Seyfert 1 Galaxies

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Edelson, R.

    2004-01-01

    The first seven years of RXTE monitoring of Seyfert 1 active galactic nuclei have been systematically analyzed to yield five homogenous samples of 2-12 keV light curves, probing hard X-ray variability on successively longer durations from approx. 1 day to approx. 3.5 years. 2-10 keV variability on time scales of approx. 1 day, as probed by ASCA, are included. All sources exhibit stronger X-ray variability towards longer time scales, with variability amplitudes saturating at the longest time scales, but the increase is greater for relatively higher luminosity sources. The well-documented anticorrelation between variability amplitude and luminosity is confirmed on all time scales. However, anticorrelations between variability amplitude and black hole mass estimate are evident on only the shortest time scales probed. The data are consistent with the models of power spectral density (PSD) movement described in Markowitz et al. (2003) and McHardy et al. (2004), whereby Seyfert 1 galaxies variability can be described by a single, universal PSD shape whose cutoff frequency scales with black hole mass. The best-fitting scaling relations between variability time scale, black hole mass and X-ray luminosity support an average accretion rate of 2% of the Eddington limit for the sample. Nearly all sources exhibit stronger variability in the relatively soft 2-4 keV band compared to the 7-12 keV band on all time scales. Color-flux diagrams support also Seyfert 1s' softening as they brighten. There are indications that relatively less luminous or less massive sources exhibit a greater degree of spectral variability for a given increase in overall flux.

  10. ROSAT PSPC and HRI observations of the composite starburst/Seyfert 2 galaxy NGC 1672

    NASA Technical Reports Server (NTRS)

    Brandt, W. N.; Halpern, Jules P.; Iwasawa, K.

    1995-01-01

    The nearby barred spiral galaxy NGC 1672 has been observed with the Position Sensitive Proportional Counter (PSPC) and High Resolution Imager (HRI) instruments on board the ROSAT X-ray satellite. NGC 1672 is thought to have an obscured Seyfert nucleus, and it has strong starburst activity as well. Three bright X-ray sources with luminosities 1-2 x 10(exp 40) erg/s are clearly identified with NGC 1672. The strongest lies at the nucleus, and the other two lie at the ends of NGC 1672's prominent bar, locations that are also bright in H alpha and near-infrared images. The nuclear source is resolved by the HRI on about the scale of the recently identified nuclear ring, and one of the sources at the ends of the bar is also probably resolved. The X-ray spectrum of the nuclear source is quite soft, having a Raymond-Smith plasma temperature of approximately equals 0.7 keV and little evidence for intrinsic absorption. The ROSAT band X-ray flux of the nuclear source appears to be dominated not by X-ray binary emission but rather by diffuse gas emission. The absorption and emission properties of the sources, as well as their spatial extents, lead us to models of superbubbles driven by supernovae. However, the large density and emission measure of the nuclear X-ray source stretch the limits that can be comfortably accommodated by these models. We do not detect direct emission from the putative Seyfert nucleus, although an alternative model for the nuclear source is thermal emission from gas that is photoionized by a hidden Seyfert nucleus. The spectra of the other two X-ray sources are harder than that of the nuclear source, and have similar difficulties with regard to superbubble models.

  11. Jet acceleration of the fast molecular outflows in the Seyfert galaxy IC 5063.

    PubMed

    Tadhunter, C; Morganti, R; Rose, M; Oonk, J B R; Oosterloo, T

    2014-07-24

    Massive outflows driven by active galactic nuclei are widely recognized to have a key role in the evolution of galaxies, by heating the ambient gas, expelling it from the nuclear regions, and thereby affecting the star-formation histories of the galaxy bulges. It has been proposed that the powerful jets of relativistic particles (such as electrons) launched by some active nuclei can both accelerate and heat the molecular gas, which often dominates the mass budgets of the outflows. Clear evidence for this mechanism, in the form of detailed associations between the molecular gas kinematics and features in the radio-emitting jets, has however been lacking. Here we report that the warm molecular hydrogen gas in the western radio lobe of the Seyfert galaxy IC 5063 is moving at high velocities-up to about 600 kilometres per second-relative to the galaxy disk. This suggests that the molecules have been accelerated by fast shocks driven into the interstellar medium by the expanding radio jets. These results demonstrate the general feasibility of accelerating molecular outflows in fast shocks driven by active nuclei. PMID:25043049

  12. Ionized gas kinematics within the inner kiloparsec of the Seyfert galaxy NGC 1365

    NASA Astrophysics Data System (ADS)

    Lena, Davide; Robinson, Andrew; Storchi-Bergmann, Thaisa; Couto, Guilherme S.; Schnorr-Müller, Allan; Riffel, Rogemar A.

    2016-07-01

    We observed the nuclear region of the galaxy NGC 1365 with the integral field unit of the Gemini Multi Object Spectrograph mounted on the GEMINI-South telescope. The field of view covers 13 × 6 arcsec2(1173 × 541 pc2) centred on the nucleus, at a spatial resolution of 52 pc. The spectral coverage extends from 5600 to 7000 Å, at a spectral resolution R = 1918. NGC 1365 hosts a Seyfert 1.8 nucleus, and exhibits a prominent bar extending out to 100 arcsec (9 kpc) from the nucleus. The field of view lies within the inner Lindblad resonance. Within this region, we found that the kinematics of the ionized gas (as traced by [O I], [N II], Hα, and [S II]) is consistent with rotation in the large-scale plane of the galaxy. While rotation dominates the kinematics, there is also evidence for a fan-shaped outflow, as found in other studies based on the [O III] emission lines. Although evidence for gas inflowing along nuclear spirals has been found in a few barred galaxies, we find no obvious signs of such features in the inner kiloparsec of NGC 1365. However, the emission lines exhibit a puzzling asymmetry that could originate from gas which is slower than the gas responsible for the bulk of the narrow-line emission. We speculate that it could be tracing gas which lost angular momentum, and is slowly migrating from the inner Lindblad resonance towards the nucleus of the galaxy.

  13. Ionized gas kinematics within the inner kiloparsec of the Seyfert galaxy NGC 1365

    NASA Astrophysics Data System (ADS)

    Lena, Davide; Robinson, Andrew; Storchi-Bergmann, Thaisa; Couto, Guilherme S.; Schnorr-Müller, Allan; Riffel, Rogemar A.

    2016-04-01

    We observed the nuclear region of the galaxy NGC 1365 with the integral field unit of the Gemini Multi Object Spectrograph mounted on the GEMINI-South telescope. The field of view covers 13″ × 6″ (1173 × 541 pc2) centered on the nucleus, at a spatial resolution of 52 pc. The spectral coverage extends from 5600 Å to 7000 Å, at a spectral resolution R = 1918. NGC 1365 hosts a Seyfert 1.8 nucleus, and exhibits a prominent bar extending out to 100″ (9 kpc) from the nucleus. The field of view lies within the inner Lindblad resonance. Within this region, we found that the kinematics of the ionized gas (as traced by [OI], [NII], Hα, and [SII]) is consistent with rotation in the large-scale plane of the galaxy. While rotation dominates the kinematics, there is also evidence for a fan-shaped outflow, as found in other studies based on the [OIII] emission lines. Although evidence for gas inflowing along nuclear spirals has been found in a few barred galaxies, we find no obvious signs of such features in the inner kiloparsec of NGC 1365. However, the emission lines exhibit a puzzling asymmetry that could originate from gas which is slower than the gas responsible for the bulk of the narrow-line emission. We speculate that it could be tracing gas which lost angular momentum, and is slowly migrating from the inner Lindblad resonance towards the nucleus of the galaxy.

  14. Spitzer Spectroscopy to Distinguish z>5 Sources of Reionization from z~2 Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Chary, Ranga-Ram; Dickinson, Mark; Lawrence, Charles; Teplitz, Harry

    2008-03-01

    Optical/near-infrared photometric redshifts of 13 red galaxies in GOODS favor z>5 redshift solutions which indicate that they are extremely massive galaxies with stellar masses exceeding 1E11 Msun. If true, these galaxies contribute the bulk of the stellar mass density at z~6 and the past star-formation in these galaxies is responsible for reionizing the intergalactic medium at z>>6. The majority of these galaxies have however found to be faint 24 micron sources which would instead suggest that they are luminous infrared galaxies (LIRGs) with L(IR)~3E11 Lsun at z~2. We propose ultradeep Spitzer/IRS LL spectroscopy which will measure the redshifts of two representative, optically invisible (i>27 mag) sources in this class and distinguish between these two widely disparate hypotheses. The detection of polycyclic aromatic hydrocarbons (PAH) in the spectra of these sources would imply that photometric redshifts of dusty infrared luminous galaxies are unreliable - a fundamental obstacle in estimating the comoving luminosity density of the Universe as a function of redshift. It would allow the shape of the dust extinction curve to be constrained and rule out the Balmer-'break' color selection as a reliable tracer of redshift. By virtue of being the deepest IRS/LL observations, it would yield the first measures of PAH line strengths in high redshift LIRGs. This will help refine the mid-infrared PAH templates that are used to estimate bolometric luminosities of galaxies detected in various mid-infrared surveys, including those which will be undertaken by WISE. The absence of PAH in the proposed spectra would imply the presence of Compton-thick AGN and/or confirm that we have identified the galaxies responsible for reionization without the need for changing the stellar initial mass function at high redshift. Spitzer offers the only opportunity to resolve this important conundrum until the James Webb Space Telescope.

  15. Is HE 0436-4717 Anemic? A deep look at a bare Seyfert 1 galaxy

    NASA Astrophysics Data System (ADS)

    Bonson, K.; Gallo, L. C.; Vasudevan, R.

    2015-06-01

    A multi-epoch, multi-instrument analysis of the Seyfert 1 galaxy HE 0436-4717 is conducted using optical to X-ray data from XMM-Newton and Swift (including the Burst Alert Telescope). Fitting of the UV-to-X-ray spectral energy distribution shows little evidence of extinction and the X-ray spectral analysis does not confirm previous reports of deep absorption edges from O VIII. HE 0436-4717 is a `bare' Seyfert with negligible line-of-sight absorption making it ideal to study the central X-ray emitting region. Three scenarios were considered to describe the X-ray data: partial covering absorption, blurred reflection, and soft Comptonization. All three interpretations describe the 0.5-10.0 keV spectra well. Extrapolating the models to 100 keV results in poorer fits for the partial covering model. When also considering the rapid variability during one of the XMM-Newton observations, the blurred reflection model appears to describe all the observations in the most self-consistent manner. If adopted, the blurred reflection model requires a very low iron abundance in HE 0436-4717. We consider the possibilities that this is an artefact of the fitting process, but it appears possible that it is intrinsic to the object.

  16. X-Ray Fluctuation Power Spectral Densities of Seyfert 1 Galaxies

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Edelson, R.; Vaughan, S.; Uttley, P.; George, I. M.; Griffiths, R. E.; Kaspi, S.; Lawrence, A.; McHandy, I.; Nandra, K.

    2003-01-01

    By combining complementary monitoring observations spanning long, medium and short time scales, we have constructed power spectral densities (PSDs) of six Seyfert 1 galaxies. These PSDs span approx. greater than 4 orders of magnitude in temporal frequency, sampling variations on time scales ranging from tens of minutes to over a year. In at least four cases, the PSD shows a "break," a significant departure from a power law, typically on time scales of order a few days. This is similar to the behavior of Galactic X-ray binaries (XRBs), lower mass compact systems with breaks on time scales of seconds. NGC 3783 shows tentative evidence for a doubly-broken power law, a feature that until now has only been seen in the (much better-defined) PSDs of low-state XRBs. It is also interesting that (when one previously-observed object is added to make a small sample of seven), an apparently significant correlation is seen between the break time scale T and the putative black hole mass M(sub BH), while none is seen between break time scale and luminosity. The data are consistent with the linear relation T = M(sub BH) /10(exp 6.5) solar mass; extrapolation over 6-7 orders of magnitude is in reasonable agreement with XRBs. All of this strengthens the case for a physical similarity between Seyfert 1s and XRBs.

  17. A Spitzer-Selected Galaxy Cluster at z=1.62

    NASA Astrophysics Data System (ADS)

    Papovich, Casey J.; Momcheva, I.; Willmer, C. N. A.; Finkelstein, K. D.; Finkelstein, S. L.; Brodwin, M.; Dunlop, J. S.; Farrah, D.; Khan, S.; Lotz, J.; McCarthy, P.; McLure, R. J.; Rieke, M.; Rudnick, G.; Sivanadam, S.; Tran, K.

    2010-01-01

    We report the discovery of a galaxy cluster at z=1.62, located in the XMM-LSS field. This cluster candidate was originally selected as an overdensity of sources with red Spitzer/IRAC colors, satisfying [3.6] - [4.5] > -0.1 AB mag, within the Spitzer Wide-Area Infrared Extragalactic (SWIRE) survey covering 9 square degrees in this field. Photometric redshifts derived from Subaru XMM Deep Survey (BViz-bands), UKIRT Infrared Deep Survey--Ultra-Deep Survey (UKIDSS-UDS, JK-bands), and from the Spitzer Public UDS survey (SpUDS, 3.6-8.0 micron) for the galaxies in and around this cluster show that this structure corresponds to a galaxy surface density of sources at z=1.6 that is >20-sigma times the mean surface density at this redshift. We obtained spectroscopic observations of galaxies in cluster using Magellan/IMACS, and measure redshifts for six galaxies in the range z=1.62-1.65, all within 1.4 arcmin of the cluster center, which corresponds to a radius of 0.5 h-1 Mpc. We measured spectroscopic redshifts for three additional sources with z=1.61-1.63 within 1.4-2.8 arcmin (0.5-1 h-1 Mpc). The cluster appears to be dominated by red galaxies, with (z - J) > 1.7 mag. The photometric redshift distributions for the brightest red galaxies are centrally peaked at z=1.62, coincident with the spectroscopically confirmed galaxies. The J versus z-J color magnitude diagram of the galaxies in this cluster shows a strong red-sequence, which includes the dominant population of red galaxies. The intercept of the red-sequence is consistent with a stellar population formed at z=3 with passive evolution, implying that most of the stellar mass in this cluster formed at that epoch. We will summarize our plans to continue the study of this cluster, and our continuing survey to identify and study other high-redshift clusters. Support for this work was provided by NASA through an award issued by JPL/Caltech.

  18. AN INFRARED CENSUS OF DUST IN NEARBY GALAXIES WITH SPITZER (DUSTINGS). I. OVERVIEW

    SciTech Connect

    Boyer, Martha L.; Sonneborn, George; McQuinn, Kristen B. W.; Gehrz, Robert D.; Skillman, Evan; Barmby, Pauline; Bonanos, Alceste Z.; Gordon, Karl D.; Meixner, Margaret; Groenewegen, M. A. T.; Lagadec, Eric; Lennon, Daniel; Marengo, Massimo; Sloan, G. C.; Van Loon, Jacco Th.; Zijlstra, Albert

    2015-01-01

    Nearby resolved dwarf galaxies provide excellent opportunities for studying the dust-producing late stages of stellar evolution over a wide range of metallicity (–2.7 ≲ [Fe/H] ≲ –1.0). Here, we describe DUSTiNGS (DUST in Nearby Galaxies with Spitzer): a 3.6 and 4.5 μm post-cryogen Spitzer Space Telescope imaging survey of 50 dwarf galaxies within 1.5 Mpc that is designed to identify dust-producing asymptotic giant branch (AGB) stars and massive stars. The survey includes 37 dwarf spheroidal, 8 dwarf irregular, and 5 transition-type galaxies. This near-complete sample allows for the building of statistics on these rare phases of stellar evolution over the full metallicity range. The photometry is >75% complete at the tip of the red giant branch for all targeted galaxies, with the exception of the crowded inner regions of IC 10, NGC 185, and NGC 147. This photometric depth ensures that the majority of the dust-producing stars, including the thermally pulsing AGB stars, are detected in each galaxy. The images map each galaxy to at least twice the half-light radius to ensure that the entire evolved star population is included and to facilitate the statistical subtraction of background and foreground contamination, which is severe at these wavelengths. In this overview, we describe the survey, the data products, and preliminary results. We show evidence for the presence of dust-producing AGB stars in eight of the targeted galaxies, with metallicities as low as [Fe/H] = –1.9, suggesting that dust production occurs even at low metallicity.

  19. The radio source and bipolar nebulosity in the Seyfert galaxy NGC 3516

    NASA Technical Reports Server (NTRS)

    Miyaji, Takamitsu; Wilson, Andrew S.; Perez-Fournon, Ismael

    1992-01-01

    Results of radio continuum and optical emission-line observations of the type 1 Seyfert galaxy NGC 3516 are presented. The radio maps reveal an elongated one-sided curved structure, which comprises a series of small-scale 'blobs' and extends up to 4 kpc from the nucleus. This radio structure is aligned and cospatial with one side of the double-sided and highly symmetric Z-shaped emission-line structure. It is argued that these morphological features are associated with a bipolar gaseous outflow from the nucleus of NGC 3516. The radio 'blobs' are elongated roughly perpendicular to the apparent local direction of the outflow, a result which is interpreted in terms of synchrotron emission from outflow-driven shock waves.

  20. Broad-band properties of the CfA Seyfert galaxies. III - Ultraviolet variability

    NASA Technical Reports Server (NTRS)

    Edelson, R. A.; Pike, G. F.; Krolik, J. H.

    1990-01-01

    A total of 657 archived IUE spectra are used to study the UV variability properties of six members of the CfA Seyfert I galaxy sample. All show strong evidence for continuum and line variations and a tendency for less luminous objects to be more strongly variable. Most objects show a clear correlation at zero lag between UV spectral index and luminosity, evidence that the variable component is an accretion disk around a black hole which is systematically smaller in less luminous sources. No correlation is seen between the continuum luminosity and equivalent width of the C IV, Mg II, and semiforbidden C III emission lines when the entire sample is examined, but a clear anticorrelation is present when only repeated observations of individual objects are considered. This is due to a combination of light-travel time effects in the broad-line region and the nonlinear responses of lines to continuum fluctuations.

  1. Einstein Observatory SSS and MPC observations of the complex X-ray spectra of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Turner, T. J.; Weaver, K. A.; Mushotzky, R. F.; Holt, S. S.; Madejski, G. M.

    1991-11-01

    The X-ray spectra of 25 Seyfert galaxies measured with the Solid State Spectrometer on the Einstein Observatory have been investigated. This new investigation utilizes simultaneous data from the Monitor Proportional Counter, and automatic correction for systematic effects in the Solid State Spectrometer which were previously handled subjectively. It is found that the best-fit single-power-law indices generally agree with those previously reported, but that soft excesses of some form are inferred for about 48 percent of the sources. One possible explanation of the soft excess emission is a blend of soft X-ray lines, centered around 0.8 keV. The implications of these results for accretion disk models are discussed.

  2. The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei II

    NASA Technical Reports Server (NTRS)

    Stoner, R.; Ptak, R.

    1975-01-01

    The radiative transfer of Ly-alpha, Ly-beta, and H-alpha in a hydrogen gas containing dust was considered with application to the nuclear gas in Seyfert galaxies. By neglecting the direct escape of line radiation and by averaging over the gas, the radiation transfer in space is suppressed and the frequency transfer only is considered. The dust degrades the line radiation via frequency-independent absorption, converting the energy to infrared luminosity. The source functions in the lines were solved, using appropriate approximations, in order to determine under what conditions the narrow component of the Balmer line radiation from the gas can be self-absorbed and degraded without similar degradation of the broad component, which originates from the suprathermals themselves. The results are used to find self-consistent values for the temperature and ionization of the gas for various amounts of dust and various concentrations of suprathermal particles.

  3. Optical monitoring of the Seyfert galaxy NGC 4151 and possible periodicities in its historical light curve

    NASA Astrophysics Data System (ADS)

    Guo, Di-Fu; Hu, Shao-Ming; Tao, Jun; Yin, Hong-Xing; Chen, Xu; Pan, Hong-Jian

    2014-08-01

    We report B, V and R band CCD photometry of the Seyfert galaxy NGC 4151 obtained with the 1.0 m telescope at Weihai Observatory of Shandong University and the 1.56 m telescope at Shanghai Astronomical Observatory from 2005 December to 2013 February. Combining all available data from literature, we have constructed a historical light curve from 1910 to 2013 to study the periodicity of the source using three different methods (the Jurkevich method, the Lomb-Scargle periodogram method and the Discrete Correlation Function method). We find possible periods of P1 = 4 ± 0.1, P2 = 7.5 ± 0.3 and P3 = 15.9 ± 0.3 yr.

  4. Ultraviolet and optical spectrophotometry of the Seyfert 1.8 galaxy Markarian 609

    NASA Technical Reports Server (NTRS)

    Rudy, Richard J.; Cohen, Ross D.; Ake, T. B.

    1988-01-01

    Ultraviolet and optical observations of the Seyfert 1.8 galaxy Mrk 609 were collected simultaneously. The observations reveal strong line and continuum emission in the UV, an increase in the flux of H-beta and He I 5876, and a decrease in the H-alpha/H-beta value since the measurements by Osterbrock (1978, 1981), as well as an extended population of early-type stars, which is considered to be the source powering the larger part of the far-IR emission. Special attention is given to the origin of steep broad-line Balmer decrement measured by Osterbrock, since the strong UV continuum and the emission lines of Mrk 609 observed rule out reddening as the cause of the Balmer decrement. It is suggested that smaller-than-normal optical depths are likely to be the cause of the decrement.

  5. Infrared emission in Seyfert 2 galaxies - Reprocessed radiation from a dusty torus?

    NASA Technical Reports Server (NTRS)

    Storchi-Bergmann, Thaisa; Mulchaey, John S.; Wilson, Andrew S.

    1992-01-01

    New and existing data for a sample of nine Seyfert 2 galaxies with known 'ionization cones' are combined in order to test whether collimation results from shadowing of radiation from a small isotropic nuclear source by a thick dusty torus. The number of ionizing photons emitted by the compact nucleus is calculated from the emission-line ratios measured for gas within the cones. On the assumption that this compact nuclear source radiates isotropically, the optical-UV power incident on the torus, which is expected to be reradiated in the IR, is determined. It is found that the observed IRAS luminosities are consistent with the torus model in eight of the nine objects with sufficient data to perform the calculation. It is concluded that the data are generally consistent with collimation and reradiation by a dusty torus.

  6. Radio lobes and forbidden O III profile substructure in Seyfert galaxies

    SciTech Connect

    Whittle, M.; Pedlar, A.; Unger, S.W.; Axon, D.J.; Meurs, E.J.A.

    1988-03-01

    High spatial and spectral resolution observations are presented for 10 Seyfert galaxies in the H-beta-forbidden O III 5007 A spectral region. In most of the objects, there is evidence for forbidden O III profile substructure, which appears to be most conspicuous close to the location of a radio lobe. The relative intensities of forbidden O III component emission and ambient forbidden O III emission vary greatly from object to object. A control sample shows little evidence for spatially resolved forbidden O III profile substructure. The forbidden O III components usually have high excitation. The component velocities can fall well outside the maximum galactic rotation amplitude and, in some cases, are opposite to the sense of rotation. This strongly suggests that the component gas does not rotate with the rest of the galactic gas but is instead undergoing systematic outflow. 47 references.

  7. The structure of the broad-line region in the Seyfert galaxy Markarian 590

    NASA Technical Reports Server (NTRS)

    Peterson, Bradley M.; Ali, Babar; Horne, Keith; Bertram, Ray; Lame, Nancy J.; Pogge, Richard W.; Wagner, R. M.

    1993-01-01

    We have undertaken a nine-month study of continuum and emission-line variability in the Seyfert galaxy Mrk 590 in order to determine the structure of the broad-line region. The H-beta variations are found to lag behind those of the optical continuum by about 19 days. We apply a maximum entropy method to solve for the transfer function which relates the line and continuum variability. This analysis suggests that there is a deficit of emission-line response due to gas along the line of sight to the continuum source, as in the case of NGC 5548, although these data do not allow us to reject with confidence models with significant line-of-sight response. We also show that the H-beta line variability is apparently confined to the core of the emission line, as suggested previously by Ferland, Korista, and Peterson (1990).

  8. RXTE Observations of the Seyfert 2 Galaxy MrK 348

    NASA Technical Reports Server (NTRS)

    Smith, David A.; Georgantopoulos, Ioannis; Warwick, Robert S.

    2000-01-01

    We present RXTE monitoring observations of the Seyfert 2 galaxy Mrk 348 spanning a 6 month period. The time-averaged spectrum in the 3-20 keV band shows many features characteristic of a Compton-thin Seyfert 2 galaxy, namely a hard underlying power-law continuum (Gamma approximately equal 1.8) with heavy soft X-ray absorption (N(sub H) approximately 10(exp 23)/sq cm) plus measurable iron K.alpha emission (equivalent width approximately 100 eV) and, at high energy, evidence for a reflection component (R approximately < 1). During the first half of the monitoring period the X-ray continuum flux from Mrk 348 remained relatively steady. However this was followed by a significant brightening of the source (by roughly a factor of 4) with the fastest change corresponding to a doubling of its X-ray flux on a timescale of about 20 days. The flux increase was accompanied by a marked softening of X-ray spectrum most likely attributable to a factor approximately 3 decline in the intrinsic line-of-sight column density. In contrast the iron K.alpha line and the reflection components showed no evidence of variability. These observations suggest a scenario in which the central X-ray source is surrounded by a patchy distribution of absorbing material located within about a light-week of the nucleus of Mrk 348. The random movement of individual clouds within the absorbing screen, across our line of sight, produces substantial temporal variations in the measured column density on timescales of weeks to months and gives rise to the observed X-ray spectral variability. However, as viewed from the nucleus the global coverage and typical thickness of the cloud layer remains relatively constant.

  9. Properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Foschini, L.; Berton, M.; Caccianiga, A.; Ciroi, S.; Cracco, V.; Peterson, B. M.; Angelakis, E.; Braito, V.; Fuhrmann, L.; Gallo, L.; Grupe, D.; Järvelä, E.; Kaufmann, S.; Komossa, S.; Kovalev, Y. Y.; Lähteenmäki, A.; Lisakov, M. M.; Lister, M. L.; Mathur, S.; Richards, J. L.; Romano, P.; Sievers, A.; Tagliaferri, G.; Tammi, J.; Tibolla, O.; Tornikoski, M.; Vercellone, S.; La Mura, G.; Maraschi, L.; Rafanelli, P.

    2015-03-01

    We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio frequencies to X-rays, and supplement these with information available from online catalogues and the literature in order to cover the full electromagnetic spectrum. This is the largest known multiwavelength survey for this type of source. We detected 90% of the sources in X-rays and found 17% at γ rays. Extreme variability at high energies was also found, down to timescales as short as hours. In some sources, dramatic spectral and flux changes suggest interplay between a relativistic jet and the accretion disk. The estimated masses of the central black holes are in the range ~106-8 M⊙, lower than those of blazars, while the accretion luminosities span a range from ~0.01 to ~0.49 times the Eddington limit, with an outlier at 0.003, similar to those of quasars. The distribution of the calculated jet power spans a range from ~1042.6 to ~1045.6 erg s-1, generally lower than quasars and BL Lac objects, but partially overlapping with the latter. Once normalised by the mass of the central black holes, the jet power of the three types of active galactic nuclei are consistent with each other, indicating that the jets are similar and the observational differences are due to scaling factors. Despite the observational differences, the central engine of RLNLS1s is apparently quite similar to that of blazars. The historical difficulties in finding radio-loud narrow-line Seyfert 1 galaxies might be due to their low power and to intermittent jetactivity. Tables 4-9 and Figs. 8-13 are available in electronic form at http://www.aanda.org

  10. A Classical Morphological Analysis of Galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G)

    NASA Astrophysics Data System (ADS)

    Buta, Ronald J.; Sheth, Kartik; Athanassoula, E.; Bosma, A.; Knapen, Johan H.; Laurikainen, Eija; Salo, Heikki; Elmegreen, Debra; Ho, Luis C.; Zaritsky, Dennis; Courtois, Helene; Hinz, Joannah L.; Muñoz-Mateos, Juan-Carlos; Kim, Taehyun; Regan, Michael W.; Gadotti, Dimitri A.; Gil de Paz, Armando; Laine, Jarkko; Menéndez-Delmestre, Karín; Comerón, Sébastien; Erroz Ferrer, Santiago; Seibert, Mark; Mizusawa, Trisha; Holwerda, Benne; Madore, Barry F.

    2015-04-01

    The Spitzer Survey of Stellar Structure in Galaxies (S4G) is the largest available database of deep, homogeneous middle-infrared (mid-IR) images of galaxies of all types. The survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications of S4G galaxies in the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. The CVRHS system follows the precepts of classical de Vaucouleurs morphology, modified to include recognition of other features such as inner, outer, and nuclear lenses, nuclear rings, bars, and disks, spheroidal galaxies, X patterns and box/peanut structures, OLR subclass outer rings and pseudorings, bar ansae and barlenses, parallel sequence late-types, thick disks, and embedded disks in 3D early-type systems. We show that our CVRHS classifications are internally consistent, and that nearly half of the S4G sample consists of extreme late-type systems (mostly bulgeless, pure disk galaxies) in the range Scd-Im. The most common family classification for mid-IR types S0/a to Sc is SA while that for types Scd to Sm is SB. The bars in these two type domains are very different in mid-IR structure and morphology. This paper examines the bar, ring, and type classification fractions in the sample, and also includes several montages of images highlighting the various kinds of “stellar structures” seen in mid-IR galaxy morphology.

  11. SEARCH FOR GAMMA-RAY EMISSION FROM X-RAY-SELECTED SEYFERT GALAXIES WITH FERMI-LAT

    SciTech Connect

    Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Buehler, R.; Cameron, R. A.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Bastieri, D.; Buson, S.; Bonamente, E.; Brigida, M.; Bruel, P.; and others

    2012-03-10

    We report on a systematic investigation of the {gamma}-ray properties of 120 hard X-ray-selected Seyfert galaxies classified as 'radio-quiet' objects, utilizing the three-year accumulation of Fermi Large Area Telescope (LAT) data. Our sample of Seyfert galaxies is selected using the Swift Burst Alert Telescope 58 month catalog, restricting the analysis to the bright sources with average hard X-ray fluxes F{sub 14-195keV} {>=} 2.5 Multiplication-Sign 10{sup -11} erg cm{sup -2} s{sup -1} at high Galactic latitudes (|b| > 10 Degree-Sign ). In order to remove 'radio-loud' objects from the sample, we use the 'hard X-ray radio loudness parameter', R{sub rX}, defined as the ratio of the total 1.4 GHz radio to 14-195 keV hard X-ray energy fluxes. Among 120 X-ray bright Seyfert galaxies with R{sub rX} <10{sup -4}, we did not find a statistically significant {gamma}-ray excess (TS > 25) positionally coincident with any target Seyferts, with possible exceptions of ESO 323-G077 and NGC 6814. The mean value of the 95% confidence level {gamma}-ray upper limit for the integrated photon flux above 100 MeV from the analyzed Seyferts is {approx_equal} 4 Multiplication-Sign 10{sup -9} photons cm{sup -2} s{sup -1} , and the upper limits derived for several objects reach {approx_equal} 1 Multiplication-Sign 10{sup -9} photons cm{sup -2} s{sup -1} . Our results indicate that no prominent {gamma}-ray emission component related to active galactic nucleus activity is present in the spectra of Seyferts around GeV energies. The Fermi-LAT upper limits derived for our sample probe the ratio of {gamma}-ray to X-ray luminosities L{sub {gamma}}/L{sub X} < 0.1, and even <0.01 in some cases. The obtained results impose novel constraints on the models for high-energy radiation of 'radio-quiet' Seyfert galaxies.

  12. Parent population of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Berton, M.; Foschini, L.; Ciroi, S.; Cracco, V.; La Mura, G.; Lister, M. L.; Mathur, S.; Peterson, B. M.; Richards, J. L.; Rafanelli, P.

    2015-06-01

    Flat-spectrum radio-loud narrow-line Seyfert 1 galaxies (NLS1s) are a recently discovered class of γ-ray emitting active galactic nuclei (AGN), that exhibit some blazar-like properties which are explained with the presence of a relativistic jet viewed at small angles. When blazars are observed at larger angles they appear as radio-galaxies, and we expect to observe an analogue parent population for beamed NLS1s. However, the number of known NLS1s with the jet viewed at large angles is not enough. Therefore, we tried to understand the origin of this deficit. Current hypotheses about the nature of parent sources are steep-spectrum radio-loud NLS1s, radio-quiet NLS1s and disk-hosted radio-galaxies. To test these hypotheses we built three samples of candidate sources plus a control sample, and calculated their black hole mass and Eddington ratio using their optical spectra. We then performed a Kolmogorov-Smirnov statistical test to investigate the compatibility of our different samples with a beamed population. Our results indicate that, when the inclination angle increases, a beamed source appears as a steep-spectrum radio-loud NLS1, or possibly even as a disk-hosted radio-galaxy with low black hole mass and high Eddington ratio. Further investigations, involving larger complete samples and observations at radio frequency, are needed to understand the incidence of disk-hosted radio-galaxies in the parent population, and to assess whether radio-quiet NLS1s can play a role, as well. Appendix A is available in electronic form at http://www.aanda.org

  13. The Spitzer/Swift Gamma-Ray Burst Host Galaxy Legacy Survey

    NASA Astrophysics Data System (ADS)

    Perley, Daniel; Berger, Edo; Butler, Nathaniel; Cenko, S. Bradley; Chary, Ranga-Ram; Cucchiara, Antonino; Ellis, Richard; Fong, Wen-fai; Fruchter, Andrew; Fynbo, Johan; Gehrels, Neil; Graham, John; Greiner, Jochen; Hjorth, Jens; Hunt, Leslie; Jakobsson, Pall; Kruehler, Thomas; Laskar, Tanmoy; Le Floc'h, Emerich; Levan, Andrew; Levesque, Emily; Littlejohns, Owen; Malesani, Daniele; Michalowski, Michal; Milvang-Jensen, Bo; Prochaska, J. Xavier; Salvaterra, Ruben; Schulze, Steve; Schady, Patricia; Tanvir, Nial; de Ugarte Postigo, Antonio; Vergani, Susanna; Watson, Darach

    2016-08-01

    Long-duration gamma-ray bursts act as beacons to the sites of star-formation in the distant universe. GRBs reveal galaxies too faint and star-forming regions too dusty to characterize in detail using any other method, and provide a powerful independent constraint on the evolution of the cosmic star-formation rate density at high-redshift. However, a full understanding of the GRB phenomenon and its relation to cosmic star-formation requires connecting the observations obtained from GRBs to the properties of the galaxies hosting them. The large majority of GRBs originate at moderate to high redshift (z>1) and Spitzer has proven crucial for understanding the host population, given its unique ability to observe the rest-frame NIR and its unrivaled sensitivity and efficiency. We propose to complete a comprehensive public legacy survey of the Swift GRB host population to build on our earlier successes and push beyond the statistical limits of previous, smaller efforts. Our survey will enable a diverse range of GRB and galaxy science including: (1) to quantitatively and robustly map the connection between GRBs and cosmic star-formation to constrain the GRB progenitor and calibrate GRB rate-based measurements of the high-z cosmic star-formation rate; (2) to constrain the luminosity function of star-forming galaxies at the faint end and at high redshift; (3) to understand how the ISM properties seen in absorption in high-redshift galaxies unveiled by GRBs - metallicity, dust column, dust properties - connect to global properties of the host galaxies such as mass and age. Building on a decade of experience at both observatories, our observations will create an enduring joint Swift-Spitzer legacy sample - providing the definitive resource with which to examine all aspects of the GRB/galaxy connection for years to come and setting the stage for intensive JWST follow-up of the most interesting sources from our sample.

  14. Stacking Searches for Greater Than 100 MeV Gamma Ray Emission from Radio Galaxies and Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Cillis, A. N.; Hartman, R. C.; Bertsch, D. L.

    2003-01-01

    The EGRET telescope on CGRO detected more than sixty sources of high-energy gamma radiation associated with active galactic nuclei (AGN). All but one of those belong to the blazar subclass; the only exception is the nearby radio galaxy Centaurus A. Since there is no obvious reason other than proximity to expect Cen A to be the only non-blazar AGN emitting in high-energy gamma rays, we have utilized the "stacking" technique to search for $>100$-MeV emission from two non-blazar AGN subclasses, radio galaxies and Seyfert galaxies. Maps of gamma-ray counts, exposure, and diffuse background have been created, then co-added in varying numbers based on sorts by redshift, 5-GHZ flux density, and optical brightness, and finally tested for gamma-ray emission. No detection significance greater than $2\\sigma$ has been found for any subclass, sorting parameter, or number of objects co-added. Monte Carlo simulations have also been performed, to validate the technique and estimate the significance of the results.

  15. The host galaxy of the gamma-ray narrow-line Seyfert 1 galaxy 1H 0323+342

    SciTech Connect

    León Tavares, J.; Chavushyan, V.; Puerari, I.; Patiño-Alvarez, V.; Carramiñana, A.; Carrasco, L.; Guichard, J.; Olguín-Iglesias, A.; Valdes, J.; Kotilainen, J.; Añorve, C.; Antón, S.; Karhunen, K.; Sanghvi, J.

    2014-11-01

    We present optical and near-infrared (NIR) imaging data of the radio-loud, narrow-line Seyfert 1 galaxy 1H 0323+342, which shows intense and variable gamma-ray activity discovered by the Fermi satellite with the Large Area Telescope. Near-infrared and optical images are used to investigate the structural properties of the host galaxy of 1H 0323+342; this together with optical spectroscopy allows us to examine its black hole mass. Based on two-dimensional (2D) multiwavelength surface-brightness modeling, we find that statistically, the best model fit is a combination of a nuclear component and a Sérsic profile (n ∼ 2.8). However, the presence of a disk component (with a small bulge n ∼ 1.2) also remains a possibility and cannot be ruled out with the present data. Although at first glance a spiral-arm-like structure is revealed in our images, a 2D Fourier analysis of the imagery suggests that this structure corresponds to an asymmetric ring, likely associated with a recent violent dynamical interaction. We discuss our results in the context of relativistic jet production and galaxy evolution.

  16. Morphological parameters of a Spitzer survey of stellar structure in galaxies

    SciTech Connect

    Holwerda, B. W.; Muñoz-Mateos, J.-C.; Sheth, K.; Kim, T.; Meidt, S.; Mizusawa, T.; Hinz, J. L.; Zaritsky, D.; Regan, M. W.; Gil de Paz, A.; Menéndez-Delmestre, K.; Seibert, M.; Ho, L. C.; Gadotti, D. A.; Erroz-Ferrer, S. E-mail: benne.holwerda@gmail.com [Instituto de Astrofísica de Canarias, Vía Láctea s and others

    2014-01-20

    The morphology of galaxies can be quantified to some degree using a set of scale-invariant parameters. Concentration (C), asymmetry (A), smoothness (S), the Gini index (G), the relative contribution of the brightest pixels to the second-order moment of the flux (M {sub 20}), ellipticity (E), and the Gini index of the second-order moment (G{sub M} ) have all been applied to morphologically classify galaxies at various wavelengths. Here, we present a catalog of these parameters for the Spitzer Survey of stellar structure in Galaxies, a volume-limited, near-infrared (NIR) imaging survey of nearby galaxies using the 3.6 and 4.5 μm channels of the Infrared Array Camera on board the Spitzer Space Telescope. Our goal is to provide a reference catalog of NIR quantified morphology for high-redshift studies and galaxy evolution models with enough detail to resolve stellar mass morphology. We explore where normal, non-interacting galaxies—those typically found on the Hubble tuning fork—lie in this parameter space and show that there is a tight relation between concentration (C {sub 82}) and M {sub 20} for normal galaxies. M {sub 20} can be used to classify galaxies into earlier and later types (i.e., to separate spirals from irregulars). Several criteria using these parameters exist to select systems with a disturbed morphology, i.e., those that appear to be undergoing a tidal interaction. We examine the applicability of these criteria to Spitzer NIR imaging. We find that four relations, based on the parameters A and S, G and M {sub 20}, G{sub M} , C, and M {sub 20}, respectively, select outliers in morphological parameter space, but each selects different subsets of galaxies. Two criteria (G{sub M} > 0.6, G > –0.115 × M {sub 20} + 0.384) seem most appropriate to identify possible mergers and the merger fraction in NIR surveys. We find no strong relation between lopsidedness and most of these morphological parameters, except for a weak dependence of lopsidedness on

  17. UBVRI Light Curves of the Seyfert Galaxy NGC 7469 During 1990-1998: Microvariability

    NASA Astrophysics Data System (ADS)

    Merkulova, N. I.

    2000-02-01

    Observations of the nuclear region of the Seyfert galaxy NGC 7469 obtained at Crimean Astrophysical Observatory with the 1.25 m telescope are presented. During 64 nights on nine observational runs between 1990 September 24 and 1998 October 22 in each spectral band of the Johnson UBVRI system, about 1500 measurements have been performed simultaneously through the round aperture 20" in diameter using differential photometry techniques. The estimated accuracy of each measurement is about 0.01 mag. During the observing period 1990-1996 the mean luminosity of the nucleus was almost constant; only overlapping brightness fluctuations were observed. The mean luminosity level has been raised in 1996 October. The peak amplitude (maximum flux/minimum flux) Fmax/Fmin=2.09 on the light curves was observed in the U band, while the minimum amplitude Fmax/Fmin=1.32 was in the I band for the entire observation period. Using structure function (SF) analysis, the following conclusions have been made: (1) Long-term variability is caused by the same processes in the optical, because the slope b of the SF is approximately equal for all wave bands, except for the I band the slope is appreciably distinguished from the others. This would be an indication of the presence of an independent IR energy source in NGC 7469. (2) Considering the same time interval (from 6 minutes to 2 hr) for intranight variability on SFs at different wave bands, one can conclude that flicker noise causes variations observed on the light curve at the UV region (U and B bands), while at the near-IR region the light curve is formed by mixed shot noise and flicker noise-the greater the wavelength, the more the contribution of shot noise processes. (3) On intranight light curves of the NGC 7469 there exist rapid flares with durations ~25 minutes at U band, ~55 minutes at B, V bands, and ~2 hr at R, I bands-a typical timescale of intranight variability increasing with the increasing wavelength. In order to examine the

  18. Multiwavelength Measures of Star Formation: Galaxies observed by GALEX, SDSS, and Spitzer

    NASA Astrophysics Data System (ADS)

    Johnson, B. D.; Schiminovich, D.; GALEX Science Team

    2006-06-01

    We combine data from SDSS and the GALEX and Spitzer observatories to create a sample of galaxies observed homogeneously from the UV to the Far-IR. This sample, consisting of ˜ 1000 galaxies observed spectroscopically by SDSS, provides a multiwavelength (presently 0.15-70 micron) view of star formation in nearby (z<0.3) galaxies with SFRs ranging from 0.01 to 100 M⊙/year. We present first results on the dust-age-color relation,showing that long wavelength-baseline colors (e.g. NUV-3.6 micron) can be cleanly decomposed into contributions from dust (measured with the infrared to UV ratio) and star formation history (measured with the relatively dust-insensitive D4000). We also show the relation of 8 micron PAH emission to other indicators of star formation and 8/24 micron vs. 24/70 micron color-color diagrams for the sample galaxies. Finally, we present initial empirical SEDs, split by relevant galaxy properties. The SEDs combined with many global measures of stellar, gas and dust properties will provide a useful local reference for models of galaxy formation and will also help guide interpretations of observations of higher redshift galaxies. We gratefully acknowledge NASA's support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the Centre National d'Etudes Spatiale of France and the Korean Ministry of Science and Technology. BDJ was supported by NASA GSRP Grant NNG05GO43H.

  19. A SAMPLE OF SEYFERT-2 GALAXIES WITH ULTRALUMINOUS GALAXY-WIDE NARROW-LINE REGIONS: QUASAR LIGHT ECHOES?

    SciTech Connect

    Schirmer, M.; Diaz, R.; Levenson, N. A.; Winge, C.; Holhjem, K.

    2013-01-20

    We report the discovery of Seyfert-2 galaxies in SDSS-DR8 with galaxy-wide, ultraluminous narrow-line regions (NLRs) at redshifts z = 0.2-0.6. With a space density of 4.4 Gpc{sup -3} at z {approx} 0.3, these 'green beans' (GBs) are amongst the rarest objects in the universe. We are witnessing an exceptional and/or short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). The main focus of this paper is on a detailed analysis of the GB prototype galaxy J2240-0927 (z = 0.326). Its NLR extends over 26 Multiplication-Sign 44 kpc and is surrounded by an extended NLR. With a total [O III] {lambda}5008 luminosity of (5.7 {+-} 0.9) Multiplication-Sign 10{sup 43} erg s{sup -1}, this is one of the most luminous NLRs known around any type-2 galaxy. Using VLT/XSHOOTER, we show that the NLR is powered by an AGN, and we derive resolved extinction, density, and ionization maps. Gas kinematics is disturbed on a global scale, and high-velocity outflows are absent or faint. This NLR is unlike any other NLR or extended emission line region known. Spectroscopy with Gemini/GMOS reveals extended, high-luminosity [O III] emission also in other GBs. WISE 24 {mu}m luminosities are 5-50 times lower than predicted by the [O III] fluxes, suggesting that the NLRs reflect earlier, very active quasar states that have strongly subsided in less than a galaxy's light-crossing time. These light echoes, or ionization echoes, are about 100 times more luminous than any other such echo known to date. X-ray data are needed for photoionization modeling and to verify the light echoes.

  20. XMM-Newton Observations of the Heavily Absorbed Seyfert 1 Galaxy IC 4329A

    SciTech Connect

    Steenbrugge, K.

    2005-01-05

    We detect seven distinct absorbing systems in the high-resolution X-ray spectrum of the Seyfert 1 galaxy IC 4329A, taken with XMM-Newton. Firstly we detect absorption due to cold gas in our own Galaxy and warm gas in the Galactic halo or the Local Group. This local warm gas is only detected through O VII absorption, from which we deduce a temperature between 0.03 and 0.2 keV. In IC 4329A we detect absorption from the host galaxy as well as from a warm absorber, close to the nucleus, which has 4 components. The absorption from the host galaxy is well modeled by neutral material. The warm absorber detected in IC 4329A is photoionized and has an ionization range between log {xi} = -1.37 and log {xi} = 2.7. A broad excess is measured at the O VIII Ly{alpha} and N VII Ly{alpha} emission lines, which can be modeled by either disklines or multiple Gaussians. From the lightcurve we find that the source changed luminosity by about 20 % over the 140 ks observation, while the spectral shape, i.e. the softness ratio did not vary. In the EPIC spectra a narrow Fe K{alpha} and Fe XXVI Ly{alpha} emission line are detected. The narrowness of the Fe K{alpha} line and the fact that there is no evidence for flux variability between different observations leads us to conclude that the Fe K{alpha} line is formed at a large distance from the central black hole.

  1. Gamma-ray Bright Narrow Line Seyfert 1s: Their Host Galaxies and Origin

    NASA Astrophysics Data System (ADS)

    Hamilton, Timothy S.; Foschini, L.

    2012-05-01

    In the last few years a new class of radio-loud AGN has emerged: gamma-ray bright Narrow Line Seyfert 1s (g-NLS1). The broader class of NLS1s (characterized by their narrow permitted lines) are usually radio-quiet, have small black holes, high Eddington ratios, and are hosted in spiral galaxies. While a few NLS1s are radio-loud, the evidence for relativistic jets was ambiguous until the discovery of strong gamma-ray emission from five of these. As NLS1s are hosted by spirals, this may break the paradigm that associates relativistic jets with elliptical galaxies. Of these five, only the nearest one has been imaged at high resolution, and it is the only one whose host galaxy can be seen. We present our analysis of archival HST images of 1H 0312+341. While we clearly see spiral arms, we find no evidence for a separate bulge and disk_in fact, no evidence for a disk at all. The best fit follows a de Vaucouleurs profile, characteristic of elliptical galaxies. Comparing with our studies of quasar hosts, we believe this combination may indicate a recent merger. The structure of 1H 0312+341 may also distinguish it from “normal” NLS1, which have pseudobulges and are fueling by secular processes, rather than mergers. But 1H 0323+341 may be an unusual g-NLS1. It shows strong disk emission, unlike its cohorts. With so few of these to study, an approach is to image the hosts of the more common radio-loud NLS1s these are drawn from.

  2. Highly ionized disc and transient outflows in the Seyfert galaxy IRAS 18325-5926

    NASA Astrophysics Data System (ADS)

    Iwasawa, K.; Fabian, A. C.; Kara, E.; Reynolds, C. S.; Miniutti, G.; Tombesi, F.

    2016-08-01

    We report on strong X-ray variability and the Fe K-band spectrum of the Seyfert galaxy IRAS 18325-5926 obtained from the 2001 XMM-Newton EPIC pn observation with a duration of ~120 ks. While the X-ray source is highly variable, the 8-10 keV band shows larger variability than that of the lower energies. Amplified 8-10 keV flux variations are associated with two prominent flares of the X-ray source during the observation. The Fe K emission is peaked at 6.6 keV with moderate broadening. It is likely to originate from a highly ionized disc with an ionization parameter of log ξ ≃ 3. The Fe K line flux responds to the main flare, which supports its disc origin. A short burst of the Fe line flux has no relation to the continuum brightness, for which we have no clear explanation. We also find transient, blueshifted Fe K absorption features that can be identified with high-velocity (~0.2c) outflows of highly ionized gas, as found in other active galaxies. The deepest absorption feature appears only briefly (~1 h) at the onset of the main flare and disappears when the flare declines. The rapid evolution of the absorption spectrum makes this source peculiar among the active galaxies with high-velocity outflows. Another detection of the absorption feature also precedes the other flare. The variability of the absorption feature partly accounts for the excess variability in the 8-10 keV band where the absorption feature appears. Although no reverberation measurement is available, the black hole mass of ~2 × 106M⊙ is inferred from the X-ray variability. When this mass is assumed, the black hole is accreting at around the Eddington limit, which may fit the highly ionized disc and strong outflows observed in this galaxy.

  3. Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Lumninous Infrared Galaxy Candidates

    NASA Technical Reports Server (NTRS)

    Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen

    2012-01-01

    We present Spitzer 3.6 and 4.5 micrometer photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 m to approximately 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (greater than 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of 7.33 x 10(exp 5) objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

  4. The Galaxy Mass Function at High-Redshift from the Largest Available Spitzer-Based Survey (SERVS)

    NASA Astrophysics Data System (ADS)

    Morice-Atkinson, Xan; Maraston, Claudia; Lacy, Mark; Capozzi, Diego

    2015-08-01

    We exploit the largest (18 deg2) and deepest (AB = 23.1) galaxy and QSO survey available up to date of five highly observed astronomical fields (SERVS) to derive the galaxy stellar mass function and detailed galaxy properties as a function of cosmic time. SERVS obtained Spitzer 3.6µm and 4.5µm magnitudes for ~1 million galaxies up to redshift ~6, which we complement with multi-wavelength data from other on-going surveys, including VIDEO, GALEX, CFHTLS, UKIDSS, etc. in order to perform full SED fitting to models. The power of Spitzer data is its sensitivity to evolved stars at high-redshift, which allows us to better constrain the galaxy star formation histories. The wide area and depth of SERVS was designed precisely to capture the light from the most massive galaxies up to high-redshift. Results and comparison with the literature will be presented.

  5. Reverberation measurements of the inner radius of the dust torus in 17 Seyfert galaxies

    SciTech Connect

    Koshida, Shintaro; Minezaki, Takeo; Yoshii, Yuzuru; Sakata, Yu; Sugawara, Shota; Kobayashi, Yukiyasu; Suganuma, Masahiro; Enya, Keigo; Tomita, Hiroyuki; Aoki, Tsutomu; Peterson, Bruce A. E-mail: minezaki@ioa.s.u-tokyo.ac.jp

    2014-06-20

    We present the results of a dust reverberation survey for 17 nearby Seyfert 1 galaxies, which provides the largest homogeneous data collection for the radius of the innermost dust torus. A delayed response of the K-band light curve after the V-band light curve was found for all targets, and 49 measurements of lag times between the flux variation of the dust emission in the K band and that of the optical continuum emission in the V band were obtained by the cross-correlation function analysis and also by an alternative method for estimating the maximum likelihood lag. The lag times strongly correlated with the optical luminosity in the luminosity range of M{sub V} = –16 to –22 mag, and the regression analysis was performed to obtain the correlation log Δt (days) = –2.11 – 0.2 M{sub V} assuming Δt∝L {sup 0.5}, which was theoretically expected. We discuss the possible origins of the intrinsic scatter of the dust lag-luminosity correlation, which was estimated to be approximately 0.13 dex, and we find that the difference of internal extinction and delayed response of changes in lag times to the flux variations could have partly contributed to intrinsic scatter. However, we could not detect any systematic change of the correlation with the subclass of the Seyfert type or the Eddington ratio. Finally, we compare the dust reverberation radius with the near-infrared interferometric radius of the dust torus and the reverberation radius of broad Balmer emission lines. The interferometric radius in the K band was found to be systematically larger than the dust reverberation radius in the same band by the about a factor of two, which could be interpreted by the difference between the flux-weighted radius and response-weighted radius of the innermost dust torus. The reverberation radius of the broad Balmer emission lines was found to be systematically smaller than the dust reverberation radius by about a factor of four to five, which strongly supports the unified

  6. KEPLER OBSERVATIONS OF THE SEYFERT 1 GALAXY II ZW 229.015

    SciTech Connect

    Carini, M. T.; Ryle, Wesley T.

    2012-04-10

    The Seyfert 1 galaxy II ZW 229.015 has been observed with the Kepler spacecraft since quarter 4 of Kepler science operations. The results of the quarters 4-7 (1 year) Kepler observations are presented in this paper. We find the source to be highly variable on multiple timescales, with discrete variations occurring on timescales as short as tens of hours with amplitudes as small as 0.5%. Such small amplitude, rapid variability has never before been detected in active galactic nuclei. The presence of a strong galaxy component dilutes the variability determined from the photometric aperture used in the standard Kepler PDC analysis. Using the tools provided by the Kepler Guest Observer Office and simultaneous V-band photometry found in the literature, we determine an optimal customized aperture for photometry of this source with Kepler. The results of a PSRESP analysis reveal tentative evidence of a characteristic variability timescale in the power spectrum. Using this timescale, we estimate the mass of the central supermassive black hole and this estimate is consistent with the virial mass estimate from reverberation mapping studies.

  7. A TWO-PHASE LOW-VELOCITY OUTFLOW IN THE SEYFERT 1 GALAXY Ark 564

    SciTech Connect

    Gupta, A.; Mathur, S.; Krongold, Y.; Nicastro, F.

    2013-05-10

    The Seyfert 1 galaxy Ark 564 was observed with Chandra high-energy transmission gratings for 250 ks. We present the high-resolution X-ray spectrum that shows several associated absorption lines. The photoionization model requires two warm absorbers (WAs) with two different ionization states (log U = 0.39 {+-} 0.03 and log U = -0.99 {+-} 0.13), both with moderate outflow velocities ({approx}100 km s{sup -1}) and relatively low line of sight column densities (log N{sub H} = 20.94 and 20.11 cm{sup -2}). The high-ionization phase produces absorption lines of O VII, O VIII, Ne IX, Ne X, Mg XI, Fe XVII, and Fe XVIII, while the low-ionization phase produces lines at lower energies (O VIand O VII). The pressure-temperature equilibrium curve for the Ark 564 absorber does not have the typical ''S'' shape, even if the metallicity is super-solar; as a result, the two WA phases do not appear to be in pressure balance. This suggests that the continuum incident on the absorbing gas is perhaps different from the observed continuum. We also estimated the mass outflow rate and the associated kinetic energy and find it to be at most 0.009% of the bolometric luminosity of Ark 564. Thus, it is highly unlikely that these outflows provide significant feedback required by the galaxy formation models.

  8. A FANAROFF-RILEY TYPE I CANDIDATE IN NARROW-LINE SEYFERT 1 GALAXY Mrk 1239

    SciTech Connect

    Doi, Akihiro; Wajima, Kiyoaki; Hagiwara, Yoshiaki; Inoue, Makoto

    2015-01-10

    We report finding kiloparsec-scale radio emissions aligned with parsec-scale jet structures in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 1239 using the Very Large Array and the Very Long Baseline Array. Thus, this radio-quiet NLS1 has a jet-producing central engine driven by essentially the same mechanism as that of other radio-loud active galactic nuclei (AGNs). Most of the radio luminosity is concentrated within 100 parsecs and overall radio morphology looks edge-darkened; the estimated jet kinetic power is comparable to Fanaroff-Riley Type I radio galaxies. The conversion from accretion to jet power appears to be highly inefficient in this highly accreting low-mass black hole system compared with that in a low-luminosity AGN with similar radio power driven by a sub-Eddington, high-mass black hole. Thus, Mrk 1239 is a crucial probe to the unexplored parameter spaces of central engines for a jet formation.

  9. Kinematics of ionized gas in the barred Seyfert galaxy NGC 4151

    NASA Astrophysics Data System (ADS)

    Asif, M. W.; Mundell, C. G.; Pedlar, A.

    2005-05-01

    We have determined the structure and kinematics of ionized gas in the weak oval bar of the archetypal Seyfert 1 galaxy, NGC 4151, using the TAURUS Fabry-Perot interferometer to simultaneously map the distribution and kinematics of Hβ emission. We also present broad-band ultraviolet imaging of the host galaxy, obtained with XMM-Newton, which shows the detailed distribution of star formation in the bar and in the optically faint outer spiral arms. We compare the distribution and kinematics of ionized gas with that previously determined in neutral hydrogen by Mundell & Shone; we suggest that the distribution of bright, patchy ultraviolet emission close to the HI shocks is consistent with ionization by star clusters that have formed in compressed pre-shock gas. These clusters then travel ballistically through the gaseous shock to ionize gas downstream along the leading edge of the bar. In addition, we detect, for the first time, ionized gas within the shock itself, which is streaming to smaller radii in the same manner as the neutral gas.

  10. Hot gas in the center of the Seyfert galaxy NGC 3079

    NASA Astrophysics Data System (ADS)

    Miyamoto, Yusuke; Nakai, Naomasa; Seta, Masumichi; Salak, Dragan; Nagai, Makoto; Ishii, Shun; Yamauchi, Aya

    2015-08-01

    The nearby (d = 19.7 Mpc) Seyfert galaxy NGC 3079 exhibits a prominent bubble emerging from the nucleus. In order to investigate the nuclear power source, we carried out ammonia observations toward the center of NGC 3079 with the Tsukuba 32-m telescope and the JVLA. The NH3 (J, K) = (1, 1) through (6,6) lines were detected in absorption at the center of NGC 3079 with the JVLA, although the profile of NH3(3,3) was in emission in contrast to the other transitions. All ammonia absorption lines have two distinct velocity components: one is at the systemic velocity (Vsys ~ 1116 km s-1) and the other is blueshifted (Vsys ~ 1020 km s-1), and both components are aligned along the nuclear jets. The blueshifted NH3(3,3) emission can be regarded as ammonia masers associated with shocks by strong winds probably from newly formed massive stars or supernova explosions in the nuclear megamaser disk. The derived rotational temperature, Trot = 120±12 K for the systemic component and Trot = 157±19 K for the blueshifted component, and fractional abundance of NH3 relative to molecular hydrogen H2 are higher than those in other galaxies reported. The high temperature environment at the center may be mainly attributed to heating by the nuclear jets.

  11. Discovery of a fast transient outflow in the Seyfert 1 galaxy NGC 985

    NASA Astrophysics Data System (ADS)

    Ebrero, J.; Kriss, J.; Kaastra, J.; Domcek, V.

    2016-06-01

    Obscuration events in active galaxies are key to understand the physical conditions and the dynamics of the gas in the vicinity of their central super-massive black hole. Using recent joint observations with XMM-Newton and the Hubble Space Telescope of the nearby Seyfert 1 galaxy NGC 985, we have monitored the pass-by of obscuring material across our line of sight, traveling at 6000 km/s. This kind of event has been recorded previously in only a handful of cases. The properties of this transient absorber suggest that it may originate very close to the broad line region, possibly in an accretion disk wind. Moreover, by analyzing past archival observations of NGC 985, we found evidence that this obscuration process is recurrent. The analysis of the RGS spectra of this source at different epochs reveals that some of the components of the persistent warm absorber vary in response to the changes in the ionizing flux caused by this transient obscurer. In this way, we are able to derive stringent upper limits on the location of the warm absorber.

  12. A Two-phase Low-velocity Outflow in the Seyfert 1 Galaxy Ark 564

    NASA Astrophysics Data System (ADS)

    Gupta, A.; Mathur, S.; Krongold, Y.; Nicastro, F.

    2013-05-01

    The Seyfert 1 galaxy Ark 564 was observed with Chandra high-energy transmission gratings for 250 ks. We present the high-resolution X-ray spectrum that shows several associated absorption lines. The photoionization model requires two warm absorbers (WAs) with two different ionization states (log U = 0.39 ± 0.03 and log U = -0.99 ± 0.13), both with moderate outflow velocities (~100 km s-1) and relatively low line of sight column densities (log N H = 20.94 and 20.11 cm-2). The high-ionization phase produces absorption lines of O VII, O VIII, Ne IX, Ne X, Mg XI, Fe XVII, and Fe XVIII, while the low-ionization phase produces lines at lower energies (O VIand O VII). The pressure-temperature equilibrium curve for the Ark 564 absorber does not have the typical "S" shape, even if the metallicity is super-solar; as a result, the two WA phases do not appear to be in pressure balance. This suggests that the continuum incident on the absorbing gas is perhaps different from the observed continuum. We also estimated the mass outflow rate and the associated kinetic energy and find it to be at most 0.009% of the bolometric luminosity of Ark 564. Thus, it is highly unlikely that these outflows provide significant feedback required by the galaxy formation models.

  13. Fe-K Line Time Variability and Ni Abundance of Distant Reflectors in Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Fukazawa, Yasushi; Furui, Shun’ya; Hayashi, Kazuma; Ohno, Masanori; Hiragi, Kazuyoshi; Noda, Hirofumi

    2016-04-01

    We have performed systematic studies of narrow Fe–K line (6.4 keV) flux variability and Ni–K line intensity for Seyfert galaxies, using Suzaku and XMM-Newton archival data. Significant Fe–K line variability of several tens of percent was detected for a pair of observations separated by 1000–2000 days (Cen A, IC 4329 A, NGC 3516, and NGC 4151) and 158 days (NGC 3516). These timescales are larger by a factor of 10–100 than the inner radius of the torus, consistent with the view that X-ray reflection by a torus is a main origin for a narrow Fe–K line. The Ni–K line was detected with a >2σ level for the Circinus galaxy, Cen A, MRK 3, NGC 4388, and NGC 4151. A mean and variance of the Ni–Kα to Fe–Kα line intensity ratios are 0.066 and 0.026, respectively. Comparing this with the Monte-Carlo simulation of reflection, the Ni to Fe abundance ratio is 1.9 ± 0.8 solar. We discuss the results and the possibility of Ni abundance enhancement.

  14. A Search for Faint, Diffuse Halo Emission in Edge-On Galaxies with Spitzer/IRAC

    NASA Astrophysics Data System (ADS)

    Ashby, Matthew; Arendt, R. G.; Pipher, J. L.; Forrest, W. J.; Marengo, M.; Barmby, P.; Willner, S. P.; Stauffer, J. R.; Fazio, G. G.

    2006-12-01

    We present deep infrared mosaics of the nearby edge-on spiral galaxies NGC 891, 4244, 4565, and 5907. These data were acquired at 3.6, 4.5, 5.8, and 8.0 microns using the Infrared Array Camera aboard Spitzer as part of GTO program number 3. This effort is designed to detect the putative faint, diffuse emission from halos and thick disks of spiral galaxies in the near-mid infrared under the thermally stable, low-background conditions of space. These conditions in combination with the advantageous viewing angles presented by these well-known edge-on spirals provide arguably the best opportunity to characterize the halo/thick disk components of such galaxies in the infrared. In this contribution we describe our observations, data reduction techniques, corrections for artifacts in the data, and the modeling approach we applied to analyze this unique dataset. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.

  15. A comprehensive analysis of the hard X-ray spectra of bright Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Lubiński, P.; Beckmann, V.; Gibaud, L.; Paltani, S.; Papadakis, I. E.; Ricci, C.; Soldi, S.; Türler, M.; Walter, R.; Zdziarski, A. A.

    2016-05-01

    Hard X-ray spectra of 28 bright Seyfert galaxies observed with INTEGRAL were analysed together with the X-ray spectra from XMM-Newton, Suzaku and RXTE. These broad-band data were fitted with a model assuming a thermal Comptonization as a primary continuum component. We tested several model options through a fitting of the Comptonized continuum accompanied by a complex absorption and a Compton reflection. Both the large data set used and the model space explored allowed us to accurately determine a mean temperature kTe of the electron plasma, the Compton parameter y and the Compton reflection strength R for the majority of objects in the sample. Our main finding is that a vast majority of the sample (20 objects) is characterized by kTe < 100 keV, and only for two objects we found kTe > 200 keV. The median kTe for entire sample is 48_{-14}^{+57} keV. The distribution of the y parameter is bimodal, with a broad component centred at ≈0.8 and a narrow peak at ≈1.1. A complex, dual absorber model improved the fit for all data sets, compared to a simple absorption model, reducing the fitted strength of Compton reflection by a factor of about 2. Modest reflection (median R ≈ 0.32) together with a high ratio of Comptonized to seed photon fluxes point towards a geometry with a compact hard X-ray emitting region well separated from the accretion disc. Our results imply that the template Seyferts spectra used in the population synthesis models of active galactic nuclei (AGN) should be revised.

  16. The new primary X-ray component confirmed in the Seyfert I galaxy IC 4329A

    NASA Astrophysics Data System (ADS)

    Miyake, Katsuma; Noda, Hirofumi; Yamada, Shin'ya; Makishima, Kazuo; Nakazawa, Kazuhiro

    2016-04-01

    The bright and highly variable Seyfert I active galactic nucleus IC 4329A was observed with Suzaku five times in 2007 August, with intervals of ˜5 days and a net exposure of 24-31 ks each. Another longer observation was carried out in 2012 August with a net exposure of 118 ks. In the six observations, a source was detected in 2-45 keV with an average 2-10 keV fluxes of (0.67-1.2) × 10-10 erg cm-2 s-1. Its intensity changed by a factor of 2 among the five observations in 2007, and 1.5 within the 2012 observation. A difference of spectrum among these observations revealed that the variability of IC 4329A was carried mainly by a power-law component with a photon index Γ ˜ 2.0. However, in addition to this primary component and its associated reflection, the broad-band Suzaku data required another, harder, and less-variable component with Γ ˜ 1.4. The presence of this new continuum was also confirmed by analyzing the same six data sets through the spectral decomposition technique developed by Noda et al. (2013a, ApJ, 771, 100). This Γ ˜ 1.4 continuum is considered to be a new primary component that has not been recognized in the spectra of IC 4329A so far, although it was recently identified in those of several other Seyfert I galaxies (Noda et al. 2013a, ApJ, 771, 100; Noda et al. 2014, ApJ, 794, 2).

  17. The new primary X-ray component confirmed in the Seyfert I galaxy IC 4329A

    NASA Astrophysics Data System (ADS)

    Miyake, Katsuma; Noda, Hirofumi; Yamada, Shin'ya; Makishima, Kazuo; Nakazawa, Kazuhiro

    2016-06-01

    The bright and highly variable Seyfert I active galactic nucleus IC 4329A was observed with Suzaku five times in 2007 August, with intervals of ˜5 days and a net exposure of 24-31 ks each. Another longer observation was carried out in 2012 August with a net exposure of 118 ks. In the six observations, a source was detected in 2-45 keV with an average 2-10 keV fluxes of (0.67-1.2) × 10-10 erg cm-2 s-1. Its intensity changed by a factor of 2 among the five observations in 2007, and 1.5 within the 2012 observation. A difference of spectrum among these observations revealed that the variability of IC 4329A was carried mainly by a power-law component with a photon index Γ ˜ 2.0. However, in addition to this primary component and its associated reflection, the broad-band Suzaku data required another, harder, and less-variable component with Γ ˜ 1.4. The presence of this new continuum was also confirmed by analyzing the same six data sets through the spectral decomposition technique developed by Noda et al. (2013a, ApJ, 771, 100). This Γ ˜ 1.4 continuum is considered to be a new primary component that has not been recognized in the spectra of IC 4329A so far, although it was recently identified in those of several other Seyfert I galaxies (Noda et al. 2013a, ApJ, 771, 100; Noda et al. 2014, ApJ, 794, 2).

  18. Spitzer Observations of Two Early-Type Spiral Galaxies with Dust Rings

    NASA Astrophysics Data System (ADS)

    Bendo, G. J.; Armus, L.; Calzetti, D.; Dale, D. A.; Draine, B. T.; Engelbracht, C. W.; Gordon, K. D.; Grauer, A.; Helou, G.; Hollenbach, D. J.; Jarrett, T. H.; Joseph, R. D.; Kennicutt, R. C.; Kewley, L. J.; Leitherer, C.; Li, A.; Malhotra, S.; Meyer, M.; Murphy, E. J.; Regan, M. W.; Rieke, G. H.; Rieke, M. J.; Roussel, H.; Sheth, K.; Smith, J. D. T.; Thornley, M. D.; Walter, F.

    2004-12-01

    We present Spitzer images of the SB0/a galaxy NGC 1291 and the SAa galaxy NGC 4594. Both galaxies contain dust rings that can be used for studying the relation between dust emission and star formation activity. At 24 microns, the nuclei of both galaxies are the brightest sources in the galaxies, and dust emission from the rings is relatively weak. At 160 microns, however, the dust rings are more prominent sources; in NGC 4594, the dust ring is the source of virtually all of the 160 micron emission. We discuss whether the 160 micron emission from the rings is related to star formation activity or to heating by older stellar populations, and we examine the relation between dust and PAH emission. For NGC 4594, we also present submillimeter data that show that the nucleus dominates the 850 micron emission. These results demonstate that the 850 micron emission cannot come from the same dust that dominates the 160 micron emission. We examine the possible mechanisms that could be generating the 850 micron emission as well as the implications for dust models and galaxy spectral energy distribution templates.

  19. He II lambda 1640/lambda 4686 and Ly-alpha/H-beta ratios in the extraordinary Seyfert galaxy Markarian 359

    NASA Technical Reports Server (NTRS)

    Macalpine, G. M.; Davidson, K.; Gull, T. R.; Wu, C.-C.

    1985-01-01

    The exceptionally narrow-lined Seyfert 1 galaxy Mrk 359 is ideally suited for determining reddening via the He II lambda 1640/lambda 4686 emission-line ratio. Here the validity of He II lines as a reddening indicator for quasars and Seyfert galaxies is reexamined and confirmed in the context of the most complete photoionization models available. In addition, lambda 1640 equivalent width measurements are shown to support previous contentions of substantial differences between observed and intrinsic quasar far-ultraviolet continua. Then IUE satellite and ground-based spectral data are presented, with the surprising result that both the lambda 1640/lambda 4686 and Ly-alpha/H-beta ratios do not differ greatly from case B recombination values in Mrk 359. This object is only slightly reddened, and it shows no evidence for extended, high-optical-depth H(+)/H(0) transition regions in the line-emitting gas. The very narrow lines and lack of deep transition regions and/or reddening may be related. In addition, Mrk 359 has low luminosity compared with most other Seyfert 1 galaxies, measured emission lines suggest an unusually high ionization parameter, and there is a hint of low nitrogen abundance. Further work is needed to examine possible relationships among all these peculiar properties.

  20. X-RAY DIPS IN THE SEYFERT GALAXY FAIRALL 9: COMPTON-THICK 'COMETS' OR A FAILED RADIO GALAXY?

    SciTech Connect

    Lohfink, Anne M.; Reynolds, Christopher S.; Mushotzky, Richard F.; Wilms, Joern

    2012-04-20

    We investigate the spectral variability of the Seyfert galaxy Fairall 9 using almost 6 years of monitoring with the Rossi X-ray Timing Explorer with an approximate time resolution of 4 days. We discover the existence of pronounced and sharp dips in the X-ray flux, with a rapid decline of the 2-20 keV flux of a factor of two or more followed by a recovery to pre-dip fluxes after {approx}10 days. These dips skew the flux distribution away from the commonly observed lognormal distribution. Dips may result from the eclipse of the central X-ray source by broad-line region clouds, as has recently been found in NGC 1365 and Mrk 766. Unlike these other examples, however, the clouds in Fairall 9 would need to be Compton-thick, and the non-dip state is remarkably free of any absorption features. A particularly intriguing alternative is that the accretion disk is undergoing the same cycle of disruption/ejection as seen in the accretion disks of broad-line radio galaxies such as 3C120 but, for some reason, fails to create a relativistic jet. This suggests that a detailed comparison of Fairall 9 and 3C120 with future high-quality data may hold the key to understanding the formation of relativistic jets in active galactic nucleus.

  1. Rest-Frame Mid-Infrared Detection of an Extremely Luminous Lyman Break Galaxy with the Spitzer Infrared Spectrograph (IRS)

    NASA Technical Reports Server (NTRS)

    Teplitz, H. I.; Charmandaris, V.; Armus, L.; Appleton, P. N.; Houck, J. R.; Soifer, B. T.; Weedman, D.; Brandl, B. R.; vanCleve, J.; Grillmair, C.; Uchid, K. I.

    2004-01-01

    We present the first rest-frame of approximately 4 microns detection of a Lyman break galaxy. The data were obtained using the 16 microns imaging capability of the Spitzer Infrared Spectrograph. The target object, J134026.44+634433.2, is an extremely luminous Lyman break galaxy at z=2.79, first identified in Sloan Digital Sky Survey (SDSS) spectra (as reported by Bentz et al.). The source is strongly detected with a flux of 0.94 +/- 0.02 mJy. Combining Spitzer and SDSS photometry with supporting ground-based J- and K-band data, we show that the spectral energy distribution is consistent with an actively star-forming galaxy. We also detect other objects in the Spitzer field of view, including a very red mid-infrared source. We find no evidence of a strong lens among the mid-infrared sources.

  2. The most distant galaxy clusters in the SPT Spitzer Deep Field Survey

    NASA Astrophysics Data System (ADS)

    Rettura, Alessandro; Stanford, S. A.; Stern, D.; Mei, S.; Brodwin, M.; Gonzalez, A. H.; Gettings, D.; Ashby, M.; Bartlett, J.; Rosati, P.

    2014-01-01

    We present a sample of more than 300 galaxy cluster candidates at z>1.3 selected within 94 deg2 from the Spitzer SPT Deep Field (SSDF) survey. To discover distant clusters at z>1.3, we have used a three-filter algorithm based upon Spitzer/IRAC color ([3.6]-[4.5]>-0.1,AB) combined with a non-detection in shallow optical data. Our sample is selected to be a complete stellar mass-limited sample at z>1.3 and therefore has a well defined survey volume. The uniqueness of SSDF resides not just in its area, one of the very largest with Spitzer, but also in its coverage by deep observations for the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). Deeper observations are also planned with the new SPT camera, SPTpol, that will reach, for the first time, SZ clusters up to 2 (George et al., 2012). This field also has deep X-ray observations from the XMM XXL Survey (Pierre et al., 2012). Thanks to this rich data set, we will be able to determine accurate cluster masses for the vast majority of our SSDF clusters at 1.3

  3. UBVRI simultaneous observations of the nucleus of Seyfert galaxy NGC 5548 in 1993-1999

    NASA Astrophysics Data System (ADS)

    Merkulova, N. I.

    2002-05-01

    An ongoing program on photometric and spectral monitoring of some bright Seyfert galaxies has been carried out at the Crimean Astrophysical Observatory since 1989. Results of photometric observations of NGC 5548 obtained with the 1.25 m telescope are reported in this paper; it focuses on the analysis of intranight variations. During 44 observational nights in 1993-1999 in each spectral band of the Johnson UBVRI system, 672 measurements have been performed simultaneously through the round aperture (diameter 15\\arcsec) using differential photometry techniques. The estimated accuracy of each measurement is about 0.01 mag. The peak amplitude R_max = Fmax /Fmin = 2.99 for the whole light curve was observed in the U band, while the minimum amplitude Fmax /Fmin =1.37 occurred in the I band during the full observation period. UBVRI observations and good sampled data of international monitoring campaigns of NGC 5548, were used to calculate Structure Functions. A comparison is made of the characteristics of the long and short time scale variations of NGC 5548 with those of NGC 4151, NGC 7469 and NGC 1275. In order to examine the intranight variations of the nucleus of NGC 5548, standard deviations (SD) of the nightly averaged flux F, and a measure of intranight variability - SD/F were calculated for each night. Using this parameter, a probability characteristics is introduced, and duty cycles (the fraction of time when the galaxy is variable), characterizing the efficiency of the central energy source, were evaluated. It is concluded that intranight variability is really transient in character and manifests itself with different probabilities for different galaxies.

  4. BROAD-LINE REVERBERATION IN THE KEPLER-FIELD SEYFERT GALAXY Zw 229-015

    SciTech Connect

    Barth, Aaron J.; Nguyen, My L.; Malkan, Matthew A.; Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Choi, Jieun; Duchene, Gaspard; Ganeshalingam, Mohan; Gorjian, Varoujan; Joner, Michael D.; Bennert, Vardha Nicola; Botyanszki, Janos; Childress, Michael; Cucciara, Antonino; Comerford, Julia M.; Da Silva, Robert; Gates, Elinor L.; Gerke, Brian F.

    2011-05-10

    The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from H{beta} reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad H{beta} flux. From cross-correlation measurements, we find that the H{beta} light curve has a rest-frame lag of 3.86{sup +0.69}{sub -0.90} days with respect to the V-band continuum variations. We also measure reverberation lags for H{alpha} and H{gamma} and find an upper limit to the H{delta} lag. Combining the H{beta} lag measurement with a broad H{beta} width of {sigma}{sub line} = 1590 {+-} 47 km s{sup -1} measured from the rms variability spectrum, we obtain a virial estimate of M{sub BH} = 1.00{sup +0.19}{sub -0.24} x 10{sup 7} M{sub sun} for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

  5. KILOPARSEC-SCALE JETS IN THREE RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES

    SciTech Connect

    Richards, Joseph L.; Lister, Matthew L.

    2015-02-10

    We have discovered kiloparsec-scale extended radio emission in three narrow-line Seyfert 1 galaxies (NLS1s) in sub-arcsecond resolution 9 GHz images from the Karl G. Jansky Very Large Array. We find all sources show two-sided, mildly core-dominated jet structures with diffuse lobes dominated by termination hotspots. These span 20–70 kpc with morphologies reminiscent of FR II radio galaxies, while the extended radio luminosities are intermediate between FR I and FR II sources. In two cases the structure is linear, while a 45° bend is apparent in the third. Very Long Baseline Array images at 7.6 GHz reveal parsec-scale jet structures, in two cases with extended structure aligned with the inner regions of the kiloparsec-scale jets. Based on this alignment, the ratio of the radio core–luminosity to the optical luminosity, the jet/counter-jet intensity and extension length ratios, and moderate core brightness temperatures (≲10{sup 10} K), we conclude these jets are mildly relativistic (β≲0.3, δ∼1−1.5) and aligned at moderately small angles to the line of sight (10–15°). The derived kinematic ages of ∼10{sup 6}–10{sup 7} yr are much younger than radio galaxies but comparable to other NLS1s. Our results increase the number of radio-loud NLS1s with known kiloparsec-scale extensions from 7 to 10 and suggest that such extended emission may be common, at least among the brightest of these sources.

  6. KILOPARSEC-SCALE RADIO STRUCTURES IN NARROW-LINE SEYFERT 1 GALAXIES

    SciTech Connect

    Doi, Akihiro; Kino, Motoki; Nagira, Hiroshi; Kawakatu, Nozomu; Nagai, Hiroshi; Asada, Keiichi

    2012-11-20

    We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters of the Very Large Array, which increases the number of known radio-loud NLS1s with kpc-scale structures to six, including two {gamma}-ray-emitting NLS1s (PMN J0948+0022 and 1H 0323+342) detected by the Fermi Gamma-ray Space Telescope. The detection rate of extended radio emissions in NLS1s is lower than that in broad-line active galactic nuclei (AGNs) with a statistical significance. We found both core-dominated (blazar-like) and lobe-dominated (radio-galaxy-like) radio structures in these six NLS1s, which can be understood in the framework of the unified scheme of radio-loud AGNs that considers radio galaxies as non-beamed parent populations of blazars. Five of the six NLS1s have (1) extended radio luminosities suggesting jet kinetic powers of {approx}> 10{sup 44} erg s{sup -1}, which is sufficient to make jets escape from hosts' dense environments; (2) black holes of {approx}> 10{sup 7} M {sub Sun }, which can generate the necessary jet powers from near-Eddington mass accretion; and (3) two-sided radio structures at kpc scales, requiring expansion rates of {approx}0.01c-0.3c and kinematic ages of {approx}> 10{sup 7} years. On the other hand, most typical NLS1s would be driven by black holes of {approx}< 10{sup 7} M {sub Sun} in a limited lifetime of {approx}10{sup 7} years. Hence, the kpc-scale radio structures may originate in a small window of opportunity during the final stage of the NLS1 phase just before growing into broad-line AGNs.

  7. Probing the Structures of Seyfert Galaxies which Exhibit Jets and Maser Activity Using X-ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kotter, J. T.; Hess, C. J.

    1997-12-01

    We studied three Seyfert galaxies with unusual morphologies through X-ray spectroscopy and plasma modeling, in order to determine the temperatures, elemental abundances, and spatial distributions of the X-ray emitting gas contained therein. NGC 4258 is known to have maser activity in the region surrounding its warped accretion disk, and it also emits jets. NGC 1097 and NGC 1068 exhibit these observational traits, jets and maser activity, respectively. Their unusual geometries and the significant reprocessing of the continuum and jets by the accretion disks make these three galaxies excellent candidates for modeling and spectroscopic interpretation which accounts for thermal instability.

  8. Near-infrared emission-line spectra of the Orion Nebula, NGC 4151, and other Seyfert galaxies

    SciTech Connect

    Osterbrock, D.E.; Shaw, R.A.; Veilleux, S. )

    1990-04-01

    Near-IR CCD moderate-resolution spectra in the 7000-11,000 wavelength range were obtained for NGC 1976 and NGC 4151 in three overlapping segments. The strongest three lines in both objects are forbidden S III 9531, He I 10830, and forbidden S III 9069. Also, lower resolution spectra of 14 additional Seyfert galaxies were obtained. In all but two of these spectra, the strongest line is forbidden S III 9531. The line strengths among these galaxies are compared to trace ionization behavior. 59 refs.

  9. X-ray bumps, iron K-alpha lines, and X-ray suppression by obscuring tori in Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Krolik, Julian H.; Madau, Piero; Zycki, Piotr T.

    1994-01-01

    We investigate the X-ray spectral properties of unobscured type 1 and obscured type 2 Seyferts as predicted by the unified Seyfert scheme. We consider the reprocessing of X-ray photons by photoelectric absorption, iron fluorescence, and Compton downscattering in the obscuring tori surrounding these active nuclei, and compute by Monte Carlo methods the reprocessed spectra as a function of the viewing angle. Depending on the optical depth and shape of the torus, and on the viewing angle, the X-ray flux can be suppressed by substantial factors when our line of sight is obscured. We show that an immediate consequence of the existence of an obscuring thick torus is the production in the spectra of type 1 Seyfert galaxies of a bump in the continuum above 10-20 keV and an Fe K-alpha line with significant equivalent width. In those type 2 Seyferts for which the hard X-ray spectrum has been substantially suppressed, the equivalent width of the Fe K-alpha line in the transmitted spectrum can be very large.

  10. The Detection of Circumnuclear X-Ray Emission from the Seyfert Galaxy NGC 3516

    NASA Technical Reports Server (NTRS)

    George, I. M.; Turner, T. J.; Netzer, H.; Kraemer, S. B.; Ruiz, J.; Chelouche, D.; Crenshaw, D. M.; Yaqoob, T.; Nandra, K.; Mushotzky, R. F.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    We present the first high-resolution, X-ray image of the circumnuclear regions of the Seyfert 1 galaxy NGC 3516, using the Chandra X-ray Observatory (CXO). All three of the CXO observations reported were performed with one of the two grating assemblies in place, and here we restrict our analysis to undispersed photons (i.e. those detected in the zeroth-order). A previously-unknown X-ray source is detected approximately 6 arcsec (1.1h(sub 75)(exp -1) kpc) NNE of the nucleus (position angle approximately 29 degrees) which we designate CXOU 110648.1 + 723412. Its spectrum can be characterized as a power law with a photon index (Gamma) approximately 1.8 - 2.6, or as thermal emission with a temperature kT approximately 0.7 - 3 keV. Assuming a location within NGC 3516, isotropic emission implies a luminosity L approximately 2 - 8 x 10(exp 39)h(sub 75)(exp-2) erg s(exp -1) in the 0.4 - 2 keV band. If due to a single point source, the object is super-Eddington for a 1.4 solar mass neutron star. However, multiple sources or a small, extended source cannot be excluded using the current data. Large-scale extended S-ray emission is also detected out to approximately 10 arcsec (approximately 2h(sub 75)(exp -1) kpc) from the nucleus to the NE and SW, and is approximately aligned with the morphologies of the radio emission and extended narrow emission line region (ENLR). The mean luminosity of this emission is 1 - 5 x 10(exp 37)h(sub 75)(exp -2) erg s(exp -1) arcsec(exp -2), in the 0.4 - 2 keV band. Unfortunately the current data cannot usefully constrain its spectrum. These results are consistent with earlier suggestions of circumnuclear X-ray emissi in NGC 3516 based on ROSAT observations, and thus provide the first clear detection of extended X-ray emission in a Seyfert 1.0 galaxy. If the extended emission is due to scattering of the nuclear X-ray continuum, then the pressure in the X-ray emitting gas is at least two orders of magnitude too small to provide the confining

  11. Studying Galaxy Formation with the Hubble, Spitzer and James Webb Space Telescopes

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan P.

    2009-01-01

    The deepest optical to infrared observations of the universe include the Hubble Deep Fields, the Great Observatories Origins Deep Survey and the recent Hubble Ultra-Deep Field. Galaxies are seen in these surveys at redshifts z greater than 6, less than 1 Gyr after the Big Bang, at the end of a period when light from the galaxies has reionized Hydrogen in the inter-galactic medium. These observations, combined with theoretical understanding, indicate that the first stars and galaxies formed at z greater than 10, beyond the reach of the Hubble and Spitzer Space Telescopes. To observe the first galaxies, NASA is planning the James Webb Space Telescope (JWST), a large (6.5m), cold (less than 50K), infrared-optimized observatory to be launched early in the next decade into orbit around the second Earth-Sun Lagrange point. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. In addition to JWST's ability to study the formation and evolution of galaxies, I will also briefly review its expected contributions to studies of the formation of stars and planetary systems, and discuss recent progress in constructing the observatory.

  12. Studying Galaxy Formation with the Hubble, Spitzer and James Webb Space Telescopes

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan P.

    2007-01-01

    The deepest optical to infrared observations of the universe include the Hubble Deep Fields, the Great Observatories Origins Deep Survey and the recent Hubble Ultra-Deep Field. Galaxies are seen in these surveys at redshifts z>6, less than 1 Gyr after the Big Bang, at the end of a period when light from the galaxies has reionized Hydrogen in the inter-galactic medium. These observations, combined with theoretical understanding, indicate that the first stars and galaxies formed at z>10, beyond the reach of the Hubble and Spitzer Space Telescopes. To observe the first galaxies, NASA is planning the James Webb Space Telescope (JWST), a large (6.5m), cold (<50K), infrared-optimized observatory to be launched early in the next decade into orbit around the second Earth- Sun Lagrange point. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. In addition to JWST's ability to study the formation and evolution of galaxies, I will also briefly review its expected contributions to studies of the formation of stars and planetary systems.

  13. Studying Galaxy Formation with the Hubble, Spitzer and James Webb Space Telescopes

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan F.; Barbier, L. M.; Barthelmy, S. D.; Cummings, J. R.; Fenimore, E. E.; Gehrels, N.; Hullinger, D. D.; Markwardt, C. B.; Palmer, D. M.; Parsons, A. M.; Sakamoto, T.

    2006-01-01

    The deepest optical to infrared observations of the universe include the Hubble Deep Fields, the Great Observatories Origins Deep Survey and the recent Hubble Ultra-Deep Field. Galaxies are seen in these surveys at redshifts 2-6, less than 1 Gyr after the Big Bang, at the end of a period when light from the galaxies has reionized Hydrogen in the inter-galactic medium. These observations, combined with theoretical understanding, indicate that the first stars and galaxies formed at z>10, beyond the reach of the Hubble and Spitzer Space Telescopes. To observe the first galaxies, NASA is planning the James Webb Space Telescope (JWST), a large (6.5m), cold (50K), infrared-optimized observatory to be launched early in the next decade into orbit around the second Earth- Sun Lagrange point. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 27 microns. In addition to JWST s ability to study the formation and evolution of galaxies, I will also briefly review its expected contributions to studies of the formation of stars and planetary systems.

  14. Studying Galaxy Formation with the Hubble, Spitzer and James Webb Space Telescopes

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan P.

    2007-01-01

    The deepest optical to infrared observations of the universe include the Hubble Deep Fields, the Great Observatories Origins Deep Survey and the recent Hubble Ultra-Deep Field. Galaxies are seen in these surveys at redshifts 2x3, less than 1 Gyr after the Big Bang, at the end of a period when light from the galaxies has reionized Hydrogen in the inter-galactic medium. These observations, combined with theoretical understanding, indicate that the first stars and galaxies formed at z>lO, beyond the reach of the Hubble and Spitzer Space Telescopes. To observe the first galaxies, NASA is planning the James Webb Space Telescope (JWST), a large (6.5m), cold (<50K), infrared-optimized observatory to be launched early in the next decade into orbit around the second Earth- Sun Lagrange point. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. In addition to JWST's ability to study the formation and evolution of galaxies, I will also briefly review its expected contributions to studies of the formation of stars and planetary systems.

  15. Star Formation in Distant Red Galaxies: Spitzer Observations in the Hubble Deep Field-South

    NASA Astrophysics Data System (ADS)

    Webb, Tracy M. A.; van Dokkum, Pieter; Egami, Eiichi; Fazio, Giovanni; Franx, Marijn; Gawiser, Eric; Herrera, David; Huang, Jiasheng; Labbé, Ivo; Lira, Paulina; Marchesini, Danilo; Maza, José; Quadri, Ryan; Rudnick, Gregory; van der Werf, Paul

    2006-01-01

    We present Spitzer 24 μm imaging of 1.5galaxies (DRGs) in the 10'×10' extended Hubble Deep Field-South of the Multiwavelength Survey by Yale-Chile. We detect 65% of the DRGs with KAB<23.2 mag at S24μm>~40 μJy and conclude that the bulk of the DRG population is dusty active galaxies. A mid-infrared (MIR) color analysis with IRAC data suggests that the MIR fluxes are not dominated by buried AGNs, and we interpret the high detection rate as evidence for a high average star formation rate of =130+/-30 Msolar yr-1. From this, we infer that DRGs are important contributors to the cosmic star formation rate density at z~2, at a level of ~0.02 Msolar yr-1 Mpc-3 to our completeness limit of KAB=22.9 mag.

  16. Optical imaging for the Spitzer Survey of Stellar Structure in Galaxies. Data release and notes on interacting galaxies

    NASA Astrophysics Data System (ADS)

    Knapen, Johan H.; Erroz-Ferrer, Santiago; Roa, Javier; Bakos, Judit; Cisternas, Mauricio; Leaman, Ryan; Szymanek, Nik

    2014-09-01

    Context. The Spitzer Survey for Stellar Structure in Galaxies (S4G) and its more recently approved extension will lead to a set of 3.6 and 4.5 μm images for 2829 galaxies, which can be used to study many different aspects of the structure and evolution of local galaxies. Aims: We have collected and re-reduced optical images of 1768 of the survey galaxies, aiming to make these available to the community as ready-to-use FITS files to be used in conjunction with the mid-IR images. Our sky-subtraction and mosaicking procedures were optimised for imaging large galaxies. We also produce false-colour images of some of these galaxies to be used for illustrative and public outreach purposes. Methods: We collected and re-processed images in five bands from the Sloan Digital Sky Survey for 1657 galaxies, which are publicly released with the publication of this paper. We observed, in only the g-band, an additional 111 S4G galaxies in the northern hemisphere with the 2.5 m Liverpool Telescope, so that optical imaging is released for 1768 galaxies, or for 62% of the S4G sample. We visually checked all images. We noted interactions and close companions in our optical data set and in the S4G sample, confirming them by determining the galaxies' radial velocities and magnitudes in the NASA-IPAC Extragalactic Database. Results: We find that 17% of the S4G galaxies (21% of those brighter than 13.5 mag) have a close companion (within a radius of five times the diameter of the sample galaxy, a recession velocity within ± 200 km s-1 and not more than 3 mag fainter) and that around 5% of the bright part of the S4G sample show significant morphological evidence of an ongoing interaction. This confirms and further supports previous estimates of these fractions. Conclusions: The over 8000 science images described in this paper, the re-processed Sloan Digital Sky Survey ones, the new Liverpool Telescope images, the set of 29 false-colour pictures, and the catalogue of companion and

  17. Intranight optical variability of γ-ray-loud narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Paliya, Vaidehi S.; Stalin, C. S.; Kumar, Brijesh; Kumar, Brajesh; Bhatt, V. K.; Pandey, S. B.; Yadav, R. K. S.

    2013-01-01

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope has detected γ-ray emission in about half a dozen narrow-line Seyfert 1 (NLSy1) galaxies. This indicates the presence of relativistic jets in these sources similar to blazars and radio galaxies. In an attempt to have an idea of the intranight optical variability (INOV) characteristics of these γ-ray-loud NLSy1 galaxies, we have carried out optical flux monitoring observations of three NLSy1 galaxies detected by Fermi/LAT: 1H 0323+342, PMN J0948+0022 and PKS 1502+036. These optical monitoring observations in RC band carried out during 2012 January-May showed the presence of rapid optical flux variations in these sources. The intranight differential light curves of these sources have revealed flux variations on time-scales of hours with amplitudes of variability >3 per cent for most of the time. However, for one source, PMN J0948+0022, we observed amplitude of variability as large as 52 per cent. On using the F-statistics to classify the variability nature of these sources, we obtained a duty cycle (DC) of INOV of ˜85 per cent. Alternatively, the more commonly used C-statistics gave a DC of INOV of ˜57 per cent. Such high DC of INOV is characteristics of the BL Lac class of active galactic nucleus. The results of our monitoring observations thus indicate that there is similarity in the INOV nature of γ-ray-loud NLSy1 galaxies and BL Lac objects, arguing strongly for the presence of relativistic jets aligned closely to the observers line of sight in γ-ray-loud NLSy1s. Moreover, our dense monitoring observations on some of the nights have led to the clear detection of some miniflares superimposed on the flux variations during the night over time-scales as short as 12 min. The detection of short time-scale flux variability in the sources studied here is clearly due to stronger time compression leading to the jets in these sources having large Doppler factors, similar to that of the inner

  18. Massive galaxies at 1-6 from the Spitzer-SERVS plus VISTA-VIDEO surveys

    NASA Astrophysics Data System (ADS)

    Sajina, Anna; Capozzi, Diego; Lacy, Mark; Maraston, Claudia; Pforr, Janine; Messias, Hugo; Farrah, Duncan; Gonzales-Solares, Eduardo; Jarvis, Matt; Marchesini, Danilo; Marchetti, Lucia; Mauduit, Jean-Claude; Vaccari, Mattia

    2014-06-01

    We exploit the uniqueness of the Spitzer Representative Volume Survey (SERVS), which provides Spitzer IRAC 3.6 and 4.5um imaging down to A 23 for a total area of 18 sq.deg., to probe massive galaxies out to 6 within a representative cosmic volume. We focus on the 1.5 sq.deg. area inside the XMM-LSS field, where we combine SERVS with VISTA-VIDEO ZYJHK_S data (down to A 24 at H and K_S). We select extremely red galaxies as either those with H-m3.6>1.6 (HIEROs) and/or K_S-m4.5>1.6 (KIEROs), and calculate their photometric redshifts and stellar population properties using different stellar population models and fitting codes. We find that (H/K)IEROs have a redshift distribution that covers 1-6; are massive (median log(Mstar/Msun)=10.8); and dusty (median E(B-V)=0.4). They have significant star-formation rates (typically 10-100Msun/yr) based on both our stellar population fitting and the fact that ~50% have MIPS24\\um and/or SPIRE250um detections. A comparison with recent stellar mass function estimates, suggests that (H/K)IERO samples contain a large fraction of the Mstar>10^11Msun galaxies at 2-5. Our study also reveals five z>5 candidates, all with Mstar>10^11Msun. Our results suggest that, over the full area of overlap between SERVS and VIDEO, we will find >10,000 (H/K)IEROs, including a few tens of z>5 massive galaxies, allowing an exceptional probe into the build-up of the stellar mass in the universe.

  19. Spitzer Observations of MAMBO Galaxies: Weeding Out Active Nuclei in Starbursting Protoellipticals

    NASA Astrophysics Data System (ADS)

    Ivison, R. J.; Greve, T. R.; Serjeant, S.; Bertoldi, F.; Egami, E.; Mortier, A. M. J.; Alonso-Herrero, A.; Barmby, P.; Bei, L.; Dole, H.; Engelbracht, C. W.; Fazio, G. G.; Frayer, D. T.; Gordon, K. D.; Hines, D. C.; Huang, J.-S.; Le Floc'h, E.; Misselt, K. A.; Miyazaki, S.; Morrison, J. E.; Papovich, C.; Pérez-González, P. G.; Rieke, M. J.; Rieke, G. H.; Rigby, J.; Rigopoulou, D.; Smail, I.; Wilson, G.; Willner, S. P.

    2004-09-01

    We present 3.6-24 μm Spitzer observations of an unbiased sample of nine luminous, dusty galaxies selected at 1200 μm by MAMBO on the IRAM 30 m telescope, a population akin to the well-known submillimeter or SCUBA galaxies (hereafter SMGs). Owing to the coarse resolution of submillimeter/millimeter cameras, SMGs have traditionally been difficult to identify at other wavelengths. We compare our multiwavelength catalogs to show that the overlap between 24 and 1200 μm must be close to complete at these flux levels. We find that all (4/4) of the most secure >=4 σ SMGs have >=4 σ counterparts at 1.4 GHz, while the fraction drops to 7/9 using all >=3 σ SMGs. We show that combining mid-infrared (MIR) and marginal (>=3 σ) radio detections provides plausible identifications in the remaining cases, enabling us to identify the complete sample. Accretion onto an obscured central engine is betrayed by the shape of the MIR continuum emission for several sources, confirming Spitzer's potential to weed out active galaxies. We demonstrate the power of an S24μm/S8μm versus S8μm/S4.5μm color-color plot as a diagnostic for this purpose. However, we conclude that the majority (~75%) of SMGs have rest-frame mid/far-IR spectral energy distributions commensurate with obscured starbursts. Sensitive 24 μm observations are clearly a useful route to identify and characterize reliable counterparts to high-redshift far-IR-bright galaxies, complementing what is possible via deep radio imaging.

  20. On the origin of the Z-shaped narrow-line region in the Seyfert galaxy NGC 3516

    NASA Technical Reports Server (NTRS)

    Veilleux, Sylvain; Tully, R. B.; Bland-Hawthorn, Jonathan

    1993-01-01

    A kinematic study has been carried out of the line-emitting gas in the Seyfert galaxy NGC 3516. The existence of two curved filaments in the central 2.5 kpc of this galaxy, which give Z-shaped appearance to its NLR. A precessing twin-jet model in which the line-emitting material is entrained by a precessing radio jet and kept ionized by the nuclear ionization field can explain the kinematic data of the brightest emission rather well. If this model is valid, this would make NGC 3516 the least luminous known active galaxy with a precessing jet. An alternative scenario assumes that the curved inner filaments represent gas entrained by a radio jet which is deflected by ram pressure from the rotation interstellar medium of the galaxy.

  1. Star Formation and Extinction in Redshift z~2 Galaxies: Inferences from Spitzer MIPS Observations

    NASA Astrophysics Data System (ADS)

    Reddy, Naveen A.; Steidel, Charles C.; Fadda, Dario; Yan, Lin; Pettini, Max; Shapley, Alice E.; Erb, Dawn K.; Adelberger, Kurt L.

    2006-06-01

    We use very deep Spitzer MIPS 24 μm observations to examine the bolometric luminosities (Lbol) and UV extinction properties of more than 200 spectroscopically identified, optically selected (UnGR) z~2 galaxies, supplemented with near-IR-selected (``BzK'' and ``DRG'') and submillimeter galaxies at similar redshifts, in the GOODS-N field. Focusing on redshifts 1.5galaxies with Hα measurements, that L5-8.5μm provides a reliable estimate of LIR for most star-forming galaxies at z~2. We show that the range of LIR in the optical/near-IR-selected samples considered extends from ~=1010 to >1012 Lsolar, with a mean ~=2×1011 Lsolar. Using 24 μm observations as an independent probe of dust extinction, we find that, as in the local universe, the obscuration LIR/L1600 is strongly dependent on Lbol and ranges in value from <1 to ~1000 within the sample considered. However, the obscuration is generally ~10 times smaller at a given Lbol at z~2 than at z~0. We show that the values of LIR and obscuration inferred from the UV spectral slope β generally agree well with the values inferred from L5-8.5μm for Lbol<1012 Lsolar. Using the specific SFRs of galaxies as a proxy for cold gas fraction, we find a wide range in the evolutionary state of galaxies at z~2, from galaxies that have just begun to form stars to those that have already accumulated most of their stellar mass and are about to become, or already are, passively evolving. Based, in part, on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA and was made possible by the generous

  2. Broad-band properties of the CfA Seyfert Galaxies. II - Infrared to millimeter properties

    NASA Technical Reports Server (NTRS)

    Edelson, R. A.; Malkan, M. A.; Rieke, G. H.

    1987-01-01

    IR and mm observations of the 48 Seyfert 1 and 2 galaxies (SG1s and SG2s) of the CfA sample (Huchra and Berg, 1987) are reported. Data obtained (1) in the NIR using the 1.55-m reflector at Stewart Observatory and the 3-m IRTF during 1984-1986, (2) in the FIR with IRAS, and (3) at 1.3 mm using the 12-m NRAO telescope at KPNO in June 1984 are presented in extensive tables and graphs and characterized in detail. None of the objects was detected at 1.3 mm, and the IR spectra of the SG2s are found to be significantly steeper (indicating thermal emission) than those of SG1s and QSOs (nonthermal emission). Turnover in the IR emission below 100 microns (in half of the objects detected at three or more IRAS wavelengths) is shown to be consistent with an accretion disk in dust-free SG1s and with unusually warm (35-65 K) dust in SG2s. It is inferred that a 60-100-micron cool excess is masking turnover in the other SGs, so that a general association of SG nuclei with strong star formation can be confirmed.

  3. Decoding the spectral variations in the bare Seyfert 1 galaxy Fairall 9

    NASA Astrophysics Data System (ADS)

    Lohfink, Anne; Reynolds, Christopher S.; Alston, William; Pinto, Ciro

    2016-04-01

    X-ray spectroscopy and variability are powerful tools to understand the fundamental physics and accretion processes occurring in active galactic nuclei. The analysis is often hampered by the wealth of processes occurring simultaneously, making them difficult to disentangle. Our talk focuses on the luminous Seyfert 1 galaxy Fairall 9, whose spectrum and timing behavior is much simpler, as it is not affected by absorption processes. We aim to present a comprehensive spectral and timing study, based on an observing campaign performed in 2014. It consisted of a long-term Swift monitoring, three pointed XMM observations and one NUSTAR observation, performed jointly with one of XMM pointings. The different flux states of the pointed XMM observations allow us to identify the continuum as the main variability driver and constrain the accretion disk parameters with unprecedented quality. We are also able to establish that the source geometry remained absolutely unchanged over several months, a behavior not seen in other AGN. We study the connection of the UV and X-ray emission from the long-term Swift monitoring and establish that the UV lags the X-rays by several days. These time lags are then compared, together with the UV rms spectrum, to what is expected for a standard thin accretion disk and put into context of the results from the analysis of the XMM and NuSTAR data. Taken together this will provide us with the most complete picture of this AGN yet.

  4. DETECTION OF HIGH VELOCITY OUTFLOWS IN THE SEYFERT 1 GALAXY Mrk 590

    SciTech Connect

    Gupta, A.; Mathur, S.; Krongold, Y.

    2015-01-01

    We report on the detection of ultra-fast outflows in the Seyfert 1 galaxy Mrk 590. These outflows are identified through highly blueshifted absorption lines of O VIII and Ne IX in the medium energy grating spectrum and Si XIV and Mg XII in the high energy grating spectrum on board the Chandra X-ray observatory. Our best-fit photoionization model requires two absorber components at outflow velocities of 0.176c and 0.0738c and a third tentative component at 0.0867c. The components at 0.0738c and 0.0867c have high ionization parameters and high column densities, similar to other ultra-fast outflows detected at low resolution by Tombesi et al. We also found suggestive evidence for super-solar silicon in these components. These outflows carry sufficient mass and energy to provide effective feedback proposed by theoretical models. The component at 0.176c, on the other hand, has a low ionization parameter and low column density, similar to those detected by Gupta et al. in Ark 564. These absorbers occupy a different locus on the velocity versus ionization parameter plane and have opened up a new parameter space of active galactic nucleus (AGN) outflows. The presence of ultra-fast outflows in moderate luminosity AGNs poses a challenge to models of AGN outflows.

  5. On the Geometry of the X-Ray--Emitting Region in Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Stern, Boris E.; Poutanen, Juri; Svensson, Roland; Sikora, Marek; Begelman, Mitchell C.

    1995-08-01

    For the first time, detailed radiative transfer calculations of Comptonized X-ray and gamma -ray radiation in a hot pair plasma above a cold accretion disk are performed using two independent codes and methods. The simulations include both energy and pair balance as well as reprocessing of the X- and gamma -rays by the cold disk. We study both plane-parallel coronae as well as active dissipation regions having shapes of hemispheres and pill boxes located on the disk surface. It is shown, contrary to earlier claims, that plane-parallel coronae in pair balance have difficulties in self-consistently reproducing the ranges of 2--20 keV spectral slopes, high-energy cutoffs, and compactnesses inferred from observations of type 1 Seyfert galaxies. Instead, the observations are consistent with the X-rays coming from a number of individual active regions located on the surface of the disk. A number of effects such as anisotropic Compton scattering, the reflection hump, feedback to the soft photon source by reprocessing, and an active region in pair equilibrium all conspire to produce the observed ranges of X-ray slopes, high-energy cutoffs, and compactnesses. The spread in spectral X-ray slopes can be caused by a spread in the properties of the active regions such as their compactnesses and their elevations above the disk surface. Simplified models invoking isotropic Comptonization in spherical clouds are no longer sufficient when interpreting the data.

  6. The Spectral Energy Distribution of the Seyfert Galaxy Ton S180

    NASA Technical Reports Server (NTRS)

    Turner, T. J.; Romano, P.; Kraemer, S. B.; George, I. M.; Yaqoob, T.; Crenshaw, D. M.; Storm, J.; Alloin, D.; Lazzaro, D.; DaSilva, L.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    We present spectral results from a multi-satellite, broad-band campaign on the Narrow-line Seyfert 1 galaxy Ton S180 performed at the end of 1999. We discuss the spectral-energy distribution of the source, combining simultaneous Chandra, ASCA and EUVE data with contemporaneous FUSE, HST, and ground-based optical and infrared data. The resulting SED shows that most of the, energy is emitted in the 10 - 100 eV regime, which must be dominated by the primary energy source. No spectral turnover is evident in the UV regime. This, the strong soft X-ray emission, and the overall shape of the SED indicate that emission from the accretion disk peaks between 15 and 100 eV. High resolution FUSE spectra showing UV absorption due to OVI and the lack of detectable X-ray absorption in the Candra spectrum demonstrate the presence of a low column density of highly ionized gas along our line of sight.

  7. UV and X-ray variability of the narrow-line Seyfert 1 galaxy Ark 564

    NASA Astrophysics Data System (ADS)

    Ezhikode, Savithri H.; Dewangan, Gulab C.; Misra, Ranjeev; Tripathi, Shruti; Sajeeth Philip, Ninan; Kembhavi, Ajit K.

    2016-07-01

    We analyze eight XMM-Newton observations of the bright Narrow Line Seyfert 1 galaxy Arakelian 564 (Ark 564). These observations, separated by ∼ 6 days, allow us to look for correlations between the simultaneous ultraviolet (UV) emission (from the Optical Monitor) with not only the X-ray flux but also with different X-ray spectral parameters. The X-ray spectra from all the observations are found to be adequately fitted by a double Comptonization model where the soft excess and the hard X-ray power law are represented by thermal Comptonization in a low temperature plasma and hot corona, respectively. Apart from the fluxes of each component, the hard X-ray power law index is found to be variable. These results suggest that the variability is associated with changes in the geometry of the inner region. The UV emission is found to be variable and well correlated with the high energy index while the correlations with the fluxes of each component are found to be weaker. Using viscous timescale arguments we rule out the possibility that the UV variation is due to the fluctuating accretion rate in the outer disk. If the UV variation is driven by X-ray reprocessing, then our results indicate that the strength of the X-ray reprocessing depends more on the geometry of the X-ray producing inner region rather than on the X-ray luminosity alone.

  8. The INTEGRAL high energy cut-off distribution of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Malizia, Angela; Ubertini, Pietro; Bird, Antony; Bazzano, Angela; Stephen, John; Molina, Manuela; Bassani, Loredana

    We present the primary continuum parameters, the photon index and the high energy cut-off, of Seyfert galaxies extracted from the INTEGRAL complete sample of AGN. We performed a broad band (0.3-100 keV) spectral analysis by fitting simultaneously the soft and hard X-ray spectra obtained by XMM and INTEGRAL/IBIS-Swift/BAT respectively in order to investigate the general properties of these parameters in particular their distribution and mean values. We present the mean photon index for the t type 1 and type 2 objects of the whole sample as well as their mean high energy cut-off. This is the first time that the cut-off energy is constrained in a such large number of AGN. Using the main parameters of the primary continuum, we are able to obtain the actual physical parameters of the Comptonizing region i.e. the plasma temperature kTe the optical depth tau. Finally, with the high S/N spectra starting to come from NuSTAR it will soon be possible to better constrain the cut-off values in many AGN, allowing the determination of more physical models and so to better understand the continuum emission and geometry of the region surrounding black holes.

  9. Seyfert galaxy narrow-line regions. I - Observations of forbidden O III lambda 5007

    NASA Technical Reports Server (NTRS)

    Vrtilek, J. M.; Carleton, N. P.

    1985-01-01

    High-resolution (23 km/s) spectra of the forbidden O III emission line at 500.7 nm from the nuclear regions of 32 Seyfert galaxies and low-redshift QSOs have been obtained at the Smithsonian Institution/University of Arizona Multiple Mirror Telescope. The properties of the data are summarized by a group of measures which efficiently describe the entire line profiles, are stable in the presence of noise, and have easily visualized geometric meaning. The distributions of line profile measures are shown. In particular, typical forbidden O III FWHM values of 200-520 km/s (mean + or - 1 sigma) and a highly significant tendency for the lines to fall off more slowly on the blue than on the red side of the peak have been found, in agreement with previous work. Using galaxian system velocities obtained from absorption-line measurements, the distribution of differences between forbidden O III emission-line velocities and galaxian system velocities has been determined; in disagreement with previous work, this distribution has been found to be consistent with symmetry about zero difference velocity.

  10. SBS 0846+513: a New Gamma-ray Emitting Narrow-line Seyfert 1 Galaxy

    NASA Technical Reports Server (NTRS)

    D'Ammando, F.; Orienti, M.; Finke, J.; Raiteri, C. M.; Angelakis, E.; Fuhrmann, L.; Giroletti, M.; Hovatta, T.; Max-Moerbeck, W.; Perkins, J. S.; Readhead, A. C. S.; Richards, J. L.; Stawarz, L.; Donato, D.

    2012-01-01

    We report Fermi-LAT observations of the radio-loud AGN SBS 0846+513 (z=0.5835), optically classified as a Narrow-Line Seyfert 1 galaxy, together with new and archival radio-to-X-ray data. The source was not active at ?-ray energies during the first two years of Fermi operation. A significant increase in activity was observed during 2010 October-2011 August. In particular a strong gamma-ray flare was observed in 2011 June reaching an isotropic ?-ray luminosity (0.1-300 GeV) of 1.0×10(sup 48) erg s(sup -1), comparable to that of the brightest flat spectrum radio quasars, and showing spectral evolution in gamma rays. An apparent superluminal velocity of (8.2+/-1.5)c in the jet was inferred from 2011-2012 VLBA images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indications of the presence of a relativistic jet as powerful as those of blazars. In addition, variability and spectral properties in radio and gamma-ray bands indicate blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazar's black hole mass distribution.

  11. X-ray evidence for ultra-fast outflows in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Tombesi, Francesco; Braito, Valentina; Reeves, James; Cappi, Massimo; Dadina, Mauro

    2012-07-01

    X-ray evidence for massive, highly ionized, ultra-fast outflows (UFOs) has been recently reported in a number of AGNs through the detection of blue-shifted Fe XXV/XXVI absorption lines. We present the results of a comprehensive spectral analysis of a large sample of 42 local Seyferts observed with XMM-Newton. Similar results are also obtained from a Suzaku analysis of 5 radio galaxies. We find that UFOs are common phenomena, being present in >40% of the sources. Their outflow velocity distribution is in the range ˜0.03--0.3c, with mean value of ˜0.14c. The ionization parameter is very high, in the range logξ˜3--6 erg~s^{-1}~cm, and the associated column densities are also large, in the range ˜10^{22}--10^{24} cm^{-2}. Their location is constrained at ˜0.0003--0.03pc (˜10^2--10^4 r_s) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are in the interval ˜0.01--1M_{⊙}~yr^{-1}. The associated mechanical power is also high, in the range ˜10^{43}--10^{45} erg/s, which indicates that UFOs are capable to provide a significant contribution to the AGN cosmological feedback.

  12. SBS 0846+513: a new γ-ray-emitting narrow-line Seyfert 1 galaxy

    NASA Astrophysics Data System (ADS)

    D'Ammando, F.; Orienti, M.; Finke, J.; Raiteri, C. M.; Angelakis, E.; Fuhrmann, L.; Giroletti, M.; Hovatta, T.; Max-Moerbeck, W.; Perkins, J. S.; Readhead, A. C. S.; Richards, J. L.; Stawarz, Ł.; Donato, D.

    2012-10-01

    We report Fermi Large Area Telescope (LAT) observations of the radio-loud active galactic nucleus SBS 0846+513 (z = 0.5835), optically classified as a narrow-line Seyfert 1 galaxy, together with new and archival radio-to-X-ray data. The source was not active at γ-ray energies during the first two years of Fermi operation. A significant increase in activity was observed during 2010 October-2011 August. In particular, a strong γ-ray flare was observed in 2011 June reaching an isotropic γ-ray luminosity (0.1-300 GeV) of 1.0 × 1048 erg s-1, comparable to that of the brightest flat spectrum radio quasars, and showing spectral evolution in γ rays. An apparent superluminal velocity of (8.2 ± 1.5)c in the jet was inferred from 2011 to 2012 Very Long Baseline Array (VLBA) images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indications of the presence of a relativistic jet as powerful as those of blazars. In addition, variability and spectral properties in radio and γ-ray bands indicate blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazar's black hole mass distribution.

  13. Is there a connection between broad absorption line quasars and narrow-line Seyfert 1 galaxies?

    SciTech Connect

    Grupe, Dirk; Nousek, John A.

    2015-02-01

    We consider whether broad absorption line quasars (BAL QSOs) and narrow-line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt and Gallagher and Boroson. For this purpose, we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/L{sub Edd}, although BAL QSOs have slightly lower L/L{sub Edd}. BAL QSOs and NLS1s in general have high Fe ii/Hβ and low [O iii]/Hβ ratios following the classic “Boroson and Green” eigenvector 1 relation. We also found that the mass accretion rates M-dot of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 M{sub ⊙} yr{sup −1}. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M−σ plot, we find that BAL QSOs contain fully developed black holes. Applying a principal component analysis to our sample, we find eigenvector 1 to correspond to the Eddington ratio L/L{sub Edd}, and eigenvector 2 to black hole mass.

  14. THE GEOMETRY OF MASS OUTFLOWS AND FUELING FLOWS IN THE SEYFERT 2 GALAXY MRK 3

    SciTech Connect

    Crenshaw, D. M.; Fischer, T. C.; Kraemer, S. B.; Schmitt, H. R.; Jaffe, Y. L.; Deo, R. P.; Collins, N. R.

    2010-03-15

    We present a study of the resolved emission-line regions and an inner dust/gas disk in the Seyfert 2 galaxy Mrk 3, based on Hubble Space Telescope observations. We show that the extended narrow-line region (ENLR), spanning {approx}4 kpc, is defined by the intersection of the ionizing bicone of radiation from the active galactic nucleus (AGN) and the inner disk, which is not coplanar with the large-scale stellar disk. This intersection leads to different position and opening angles of the ENLR compared to the narrow-line region (NLR). A number of emission-line arcs in the ENLR appear to be continuations of dust lanes in the disk, supporting this geometry. The NLR, which consists of outflowing emission-line knots spanning the central {approx}650 pc, is in the shape of a backward S. This shape may arise from rotation of the gas, or it may trace the original fueling flow close to the nucleus that was ionized after the AGN turned on.

  15. An XMM-Newton Study of the Bright Narrow-Line Seyfert 1 Galaxy Arakelian 564

    NASA Technical Reports Server (NTRS)

    Brandt, Niel

    2004-01-01

    We report on two XMM-Newton observations of the bright Narrow-Line Seyfert 1 galaxy Ark 564 taken one year apart (2000 June and 2001 June). The 0.6-10 keV continuum is well described by a soft blackbody component (kT - 140-150 eV) plus a steep power law (Gamma - 2.50-2.55). No significant spectral changes are observed between the two observations, although the X-ray flux in the second observation is - 40-50 per cent lower. In both observations we detect a significant absorption edge at a rest-frame energy of - 0.73 keV, corresponding to 0 VII. The presence of the absorption feature is confirmed by a simultaneous Chandra grating observation in 2000 June, although the best-fitting edge threshold is at a slightly lower energy in the Chandra data, possibly because of a different parameterization of the underlying X-ray continuum. We find tentative evidence for a broad iron emission line in the 2000 June observation. The results from an analysis of the power spectral density (PSD) function are also presented. The present XMM-Newton data support the idea that the PSD shows two breaks, although the location of the high-frequency break requires further constraints.

  16. NGC 4051 and the Nature of Narrow-Line Seyfert I Galaxies

    NASA Technical Reports Server (NTRS)

    Peterson, B. M.; McHardy, I. M.; Wilkes, B. J.

    2004-01-01

    We report on the results of a three-year program of coordinated X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051. The principal results of this program are: (1) The H-beta emission line time lag and Doppler width yield a virial mass estimate of about 1.1 mission solar masses, at the extreme low end of AGN masses. A plausible adjustment for inclination effects increases this mass slightly to about 1.4 mission solar masses. (2) During the third year of this campaign, both the X-ray continuum and the He II 4686 line went into extremely low states, although the optical continuum and the H-beta broad line were both still present and variable. We suggest that the inner part of the accretion disk may have gone into an advection-dominated state, yielding little radiation from the hotter inner disk. (3) The He II 4686 line is almost five times as broad as H-beta, and it is strongly blueward asymmetric, as are the high-ionization UV lines recorded in archive spectra of NGC 4051. The data are consistent with the Balmer lines arising in a low-inclination disk-like configuration, and the high-ionization lines arising in an outflowing wind, of which we observe preferentially the near side.

  17. Is There a Connection between Broad Absorption Line Quasars and Narrow-Line Seyfert 1 Galaxies?

    NASA Astrophysics Data System (ADS)

    Grupe, Dirk; Nousek, John. A.

    2015-02-01

    We consider whether broad absorption line quasars (BAL QSOs) and narrow-line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt & Gallagher and Boroson. For this purpose, we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/{{L}Edd}, although BAL QSOs have slightly lower L/{{L}Edd}. BAL QSOs and NLS1s in general have high Fe ii/Hβ and low [O iii]/Hβ ratios following the classic “Boroson & Green” eigenvector 1 relation. We also found that the mass accretion rates \\dot{M} of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 {{M}⊙ } yr-1. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M-σ plot, we find that BAL QSOs contain fully developed black holes. Applying a principal component analysis to our sample, we find eigenvector 1 to correspond to the Eddington ratio L/{{L}Edd}, and eigenvector 2 to black hole mass.

  18. Variations of the ultraviolet Fe II and Balmer continuum emission in the Seyfert galaxy NGC 5548

    NASA Technical Reports Server (NTRS)

    Maoz, D.; Netzer, H.; Peterson, B. M.; Bechtold, J.; Bertram, R.; Bochkarev, N. G.; Carone, T. E.; Dietrich, M.; Filippenko, A. V.; Kollatschny, W.

    1993-01-01

    We present measurements of the Balmer continuum/Fe II emission blend between 2160 and 4130 A in the Seyfert galaxy NGC 5548. The measurements are from spectra obtained as part of the combined space-based and ground-based monitoring program of this object in 1988-1989. An iterative scheme is used to determine and subtract the continuum emission underlying the emission blend so as to obtain a light curve sampled once every four days. The small blue bump is an important component of the emission-line cooling, constituting about one third of the line flux in this object. Its flux varies with an amplitude of approximately +/- 20 percent about the mean, similar to the amplitude of the Balmer line variations during the same period. Its light curve resembles that of Ly-alpha, with a lag of about 10 days behind the continuum variations. The bump variation amplitude is independent of the wavelength interval where it is measured, which indicates that both the Balmer continuum and Fe II emission have comparable variation amplitudes. These results suggest that the Fe II UV multiplets and the Balmer continuum are emitted in the same parts of the broad-line region as most other broad emission lines in this object.

  19. Evidence for a supermassive black hole in the nucleus of the Seyfert galaxy NGC 5548

    NASA Technical Reports Server (NTRS)

    Crenshaw, D. Michael; Blackwell, James H., Jr.

    1990-01-01

    The international campaign to monitor the variable Seyfert 1 galaxy NGC 5548 with the IUE has provided an extensive and well-sampled set of spectroscopic observations. These observations are used to study the response of the C IV 1550 A emission-line profile to changes in the photoionizing continuum. Near the end of the IUE campaign, the continuum flux at 1440 A and the total C IV flux dopped by factors of 2.9 and 1.8, respectively, in 16 days. The red wing of the C IV profile responded more rapidly to the sharp continuum drop than the blue wing, indicating that clouds in the inner broad-line region (BLR) are undergoing gravitational infall. These results provide direct evidence that the central engine is a supermassive object, presumably a black hole, with a mass on the order of 10 to the 7th solar masses. Analysis of the profile variations also demonstrates that excess emission in the blue wing of C IV is from a component that is physically distinct from the bulk of the BLR.

  20. Galaxies

    SciTech Connect

    Not Available

    1981-01-01

    Normal galaxies, radio galaxies, and Seyfert galaxies are considered. The large magellanic cloud and the great galaxy in Andromedia are highlighted. Quasars and BL lacertae objects are also discussed and a review of the spectral observations of all of these galaxies and celestial objects is presented.

  1. Spitzer mid-infrared point sources in the fields of nearby galaxies

    NASA Astrophysics Data System (ADS)

    Williams, S. J.; Bonanos, A. Z.

    2016-03-01

    Aims: To complement the study of transient phenomena and to assist subsequent observations in the mid-infrared, we extract point source photometry from archival mosaics of nearby galaxies with high star formation rates within 4 Mpc. Methods: Point spread function photometry was performed on sources detected in both Spitzer IRAC 3.6 μm and 4.5 μm bands at greater than 3σ above background. These data were then supplemented by aperture photometry in the IRAC 5.8 μm and 8.0 μm bands conducted at the positions of the shorter wavelength sources. For sources with no detected object in the longer wavelengths, we estimated magnitude limits based on the local sky background. Results: We present Spitzer IRAC mid-infrared point source catalogs for mosaics covering the fields of the nearby (≲4 Mpc) galaxies NGC 55, NGC 253, NGC 2366, NGC 4214, and NGC 5253. We detect a total of 20159 sources in these five fields. The individual galaxy point source breakdown is the following: NGC 55, 8746 sources; NGC 253, 9001 sources; NGC 2366, 505 sources; NGC 4214, 1185 sources; NGC 5253, 722 sources. The completeness limits of the full catalog vary with bandpass and were found to be m3.6 = 18.0, m4.5 = 17.5, m5.8 = 17.0, and m8.0 = 16.5 mag. For all galaxies, this corresponds to detection of point sources brighter than M3.6 = -10. These catalogs can be used as a reference for stellar population investigations, individual stellar object studies, and in planning future mid-infrared observations with the James Webb Space Telescope. Based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.Full Tables 2-6 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/587/A121

  2. THE DIFFERENT NATURE OF SEYFERT 2 GALAXIES WITH AND WITHOUT HIDDEN BROAD-LINE REGIONS

    SciTech Connect

    Wu Yuzhong; Zhang Enpeng; Liang Yanchun; Zhang Chengmin; Zhao Yongheng E-mail: yzhao@nao.cas.cn

    2011-04-01

    We compile a large sample of 120 Seyfert 2 galaxies (Sy2s) which contains 49 hidden broad-line region (HBLR) Sy2s and 71 non-HBLR Sy2s. From the difference in the power sources between two groups, we test whether HBLR Sy2s are dominated by active galactic nuclei (AGNs) and whether non-HBLR Sy2s are dominated by starbursts. We show that (1) HBLR Sy2s have larger accretion rates than non-HBLR Sy2s; (2) HBLR Sy2s have larger [Ne V] {lambda}14.32/[Ne II] {lambda}12.81 and [O IV] {lambda}25.89/[Ne II] {lambda}12.81 line ratios than non-HBLR Sy2s; and (3) HBLR Sy2s have smaller IRAS f{sub 60}/f{sub 25} flux ratios, which show the relative strength of the host galaxy and nuclear emission, than non-HBLR Sy2s. Consequently, we suggest that HBLR Sy2s and non-HBLR Sy2s are AGN dominated and starburst dominated, respectively. In addition, non-HBLR Sy2s can be classified into luminous (L{sub [OIII]}>10{sup 41} erg s{sup -1}) and less luminous (L{sub [OIII]} < 10{sup 41} erg s{sup -1}) samples, when considering only their obscuration. We suggest that (1) the invisibility of polarized broad lines (PBLs) in the luminous non-HBLR Sy2s depends on the obscuration and (2) the invisibility of PBLs in the less luminous non-HBLR Sy2s depends on the very low Eddington ratio rather than the obscuration.

  3. The Peculiar Radio-loud Narrow Line Seyfert 1 Galaxy 1H 0323+342

    NASA Astrophysics Data System (ADS)

    Paliya, Vaidehi S.; Sahayanathan, S.; Parker, M. L.; Fabian, A. C.; Stalin, C. S.; Anjum, Ayesha; Pandey, S. B.

    2014-07-01

    We present a multiwavelength study of the radio-loud narrow-line Seyfert 1 galaxy (NLSy1) 1H 0323+342, detected by the Fermi Gamma-Ray Space Telescope. Multiband light curves show many orphan X-ray and optical flares having no corresponding γ-ray counterparts. Such anomalous variability behavior can be due to different locations of the emission region from the central source. During a large flare, a γ-ray flux doubling timescale as small as ~3 hr is noticed. We built spectral energy distributions (SEDs) during different activity states and modeled them using a one-zone leptonic model. The shape of the optical/UV component of the SEDs is dominated by accretion disk emission in all the activity states. In the X-ray band, significant thermal emission from the hot corona is inferred during quiescent and first flaring states; however, during subsequent flares, the nonthermal jet component dominates. The γ-ray emission in all the states can be well explained by inverse-Compton scattering of accretion disk photons reprocessed by the broad-line region. The source showed violent intra-night optical variability, coinciding with one of the high γ-ray activity states. An analysis of the overall X-ray spectrum fitted with an absorbed power-law plus relativistic reflection component hints at the presence of an Fe Kα line and returns a high black hole spin value of a = 0.96 ± 0.14. We argue that 1H 0323+342 possesses dual characteristics, akin to both flat-spectrum radio quasars (FSRQs) and radio-quiet NLSy1 galaxies, though at a low jet power regime compared to powerful FSRQs.

  4. Fermi monitoring of radio-loud narrow-line Seyfert 1 galaxies

    SciTech Connect

    Paliya, Vaidehi S.; Stalin, C. S.; Ravikumar, C. D.

    2015-02-01

    We present detailed analysis of the γ-ray flux variability and spectral properties of the five radio-loud narrow line Seyfert 1 (RL-NLSy1) galaxies, detected by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope, namely 1H 0323+342, SBS 0846+513, PMN J0948+0022, PKS 1502+036, and PKS 2004−447. The first three sources show significant flux variations, including the rapid variability of a few hours by 1H 0323+342. The average γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 shows deviation from a simple power-law (PL) behavior, whereas the PL model gives a better fit for the other three sources. The spectra of 1H 0323+342, SBS 0846+513, and PMN J0948+0022, which are in low, flaring, and moderately active states, respectively, show significant curvature. Such curvature in the γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 could be due to the emission region located inside the broad line region (BLR) where the primary mechanism of the γ-ray emission is inverse-Compton (IC) scattering of BLR photons occurring in the Klein–Nishina regime. The γ-ray emission of SBS 0846+513 is explained by IC scattering of dusty torus photons, which puts the emission region outside the BLR and thus under the Thomson regime. Therefore, the observed curvature of SBS 0846+513 could be intrinsic to the particle energy distribution. The presence of curvature in the γ-ray spectrum and flux variability amplitudes of some of the RL-NLSy1 galaxies suggests that these sources could be akin to low/moderate jet power flat spectrum radio quasars.

  5. The peculiar radio-loud narrow line Seyfert 1 galaxy 1H 0323+342

    SciTech Connect

    Paliya, Vaidehi S.; Stalin, C. S.; Sahayanathan, S.; Parker, M. L.; Fabian, A. C.; Anjum, Ayesha; Pandey, S. B.

    2014-07-10

    We present a multiwavelength study of the radio-loud narrow-line Seyfert 1 galaxy (NLSy1) 1H 0323+342, detected by the Fermi Gamma-Ray Space Telescope. Multiband light curves show many orphan X-ray and optical flares having no corresponding γ-ray counterparts. Such anomalous variability behavior can be due to different locations of the emission region from the central source. During a large flare, a γ-ray flux doubling timescale as small as ∼3 hr is noticed. We built spectral energy distributions (SEDs) during different activity states and modeled them using a one-zone leptonic model. The shape of the optical/UV component of the SEDs is dominated by accretion disk emission in all the activity states. In the X-ray band, significant thermal emission from the hot corona is inferred during quiescent and first flaring states; however, during subsequent flares, the nonthermal jet component dominates. The γ-ray emission in all the states can be well explained by inverse-Compton scattering of accretion disk photons reprocessed by the broad-line region. The source showed violent intra-night optical variability, coinciding with one of the high γ-ray activity states. An analysis of the overall X-ray spectrum fitted with an absorbed power-law plus relativistic reflection component hints at the presence of an Fe Kα line and returns a high black hole spin value of a = 0.96 ± 0.14. We argue that 1H 0323+342 possesses dual characteristics, akin to both flat-spectrum radio quasars (FSRQs) and radio-quiet NLSy1 galaxies, though at a low jet power regime compared to powerful FSRQs.

  6. FINDING {eta} CAR ANALOGS IN NEARBY GALAXIES USING SPITZER. I. CANDIDATE SELECTION

    SciTech Connect

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S. E-mail: kstanek@astronomy.ohio-state.edu

    2013-04-10

    The late-stage evolution of the most massive stars such as {eta} Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of {eta} Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC images of seven nearby ({approx}< 4 Mpc) galaxies to search for such analogs. We find 34 candidates with a flat or rising mid-IR spectral energy distributions toward longer mid-infrared wavelengths that emit >10{sup 5} L{sub Sun} in the IRAC bands (3.6 to 8.0 {mu}m) and are not known to be background sources. Based on our estimates for the expected number of background sources, we expect that follow-up observations will show that most of these candidates are not dust enshrouded massive stars, with an expectation of only 6 {+-} 6 surviving candidates. Since we would detect true analogs of {eta} Car for roughly 200 years post-eruption, this implies that the rate of eruptions like {eta} Car is less than the core-collapse supernova rate. It is possible, however, that every M > 40 M{sub Sun} star undergoes such eruptions given our initial results. In Paper II we will characterize the candidates through further analysis and follow-up observations, and there is no barrier to increasing the galaxy sample by an order of magnitude. The primary limitation of the present search is that Spitzer's resolution limits us to the shorter wavelength IRAC bands. With the James Webb Space Telescope, such surveys can be carried out at the far more optimal wavelengths of 10-30 {mu}m, allowing identification of {eta} Car analogs for millennia rather than centuries post-eruption.

  7. Spitzer Imaging of Strongly lensed Herschel-selected Dusty Star-forming Galaxies

    NASA Astrophysics Data System (ADS)

    Ma, Brian; Cooray, Asantha; Calanog, J. A.; Nayyeri, H.; Timmons, N.; Casey, C.; Baes, M.; Chapman, S.; Dannerbauer, H.; da Cunha, E.; De Zotti, G.; Dunne, L.; Farrah, D.; Fu, Hai; Gonzalez-Nuevo, J.; Magdis, G.; Michałowski, M. J.; Oteo, I.; Riechers, D. A.; Scott, D.; Smith, M. W. L.; Wang, L.; Wardlow, J.; Vaccari, M.; Viaene, S.; Vieira, J. D.

    2015-11-01

    We present the rest-frame optical spectral energy distribution (SED) and stellar masses of six Herschel-selected gravitationally lensed dusty, star-forming galaxies (DSFGs) at 1 < z < 3. These galaxies were first identified with Herschel/SPIRE imaging data from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). The targets were observed with Spitzer/IRAC at 3.6 and 4.5 μm. Due to the spatial resolution of the IRAC observations at the level of 2″, the lensing features of a background DSFG in the near-infrared are blended with the flux from the foreground lensing galaxy in the IRAC imaging data. We make use of higher resolution Hubble/WFC3 or Keck/NIRC2 Adaptive Optics imaging data to fit light profiles of the foreground lensing galaxy (or galaxies) as a way to model the foreground components, in order to successfully disentangle the foreground lens and background source flux densities in the IRAC images. The flux density measurements at 3.6 and 4.5 μm, once combined with Hubble/WFC3 and Keck/NIRC2 data, provide important constraints on the rest-frame optical SED of the Herschel-selected lensed DSFGs. We model the combined UV- to millimeter-wavelength SEDs to establish the stellar mass, dust mass, star formation rate, visual extinction, and other parameters for each of these Herschel-selected DSFGs. These systems have inferred stellar masses in the range 8 × 1010-4 × 1011 M⊙ and star formation rates of around 100 M⊙ yr-1. This puts these lensed submillimeter systems well above the SFR-M* relation observed for normal star-forming galaxies at similar redshifts. The high values of SFR inferred for these systems are consistent with a major merger-driven scenario for star formation.

  8. Mapping the Spatial Distribution of Molecular Hydrogen and PAH emission in Nearby Galaxies with the Spitzer Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Brunner, Gregory; Dufour, R. J.; Sheth, K.; Armus, L.; Schinnerer, E.; Vogel, S.; Wolfire, M.

    2007-12-01

    We have embarked on an archival program to map the spatial distribution of pure rotational molecular hydrogen (H2) line emission and polycyclic aromatic hydrogen (PAH) emission (from the 6.2, 7.7, 8.6, 11.3, 12.7, and 17.1 micron PAH features) in nearby galaxies using spatially resolved Spitzer IRS spectra acquired as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) and other Spitzer programs. We present maps of the H2 and PAH emission for several galaxies (M51, M95, and NGC 3521). We compare the emission distributions in order to understand how H2, PAHs, and ionized gas are spatially correlated across dynamically distinct regions in nearby galaxies. This work is based on observations and archival data obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by both AURA grant GO10822.1 and an award issued by JPL/Caltech to Rice University.

  9. Spitzer Point-source Catalogs of ~ 300,000 Stars in Seven Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S.; Sonneborn, G.

    2015-08-01

    We present Spitzer IRAC 3.6-8 μ {{m}} and Multiband Imaging Photometer 24 μ {{m}} point-source catalogs for seven galaxies: NGC 6822, M33, NGC 300, NGC 2403, M81, NGC 0247, and NGC 7793. The catalogs contain a total of ˜300,000 sources and were created by dual-band selection of sources with \\gt 3σ detections at both 3.6 and 4.5 μ {{m}}. The source lists become significantly incomplete near {m}3.6={m}4.5≃ 18. We complement the 3.6 and 4.5 μ {{m}} fluxes with 5.8, 8.0, and 24 μ {{m}} fluxes or 3σ upper limits using a combination of PSF and aperture photometry. This catalog is a resource as an archive for studying mid-infrared transients and for planning observations with the James Webb Space Telescope. Based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  10. Spitzer Spectroscopy of Gaseous Halos of Nearby Edge-on Galaxies

    NASA Astrophysics Data System (ADS)

    Rand, Richard; Benjamin, Robert; Wood, Kenneth

    2007-05-01

    The majority of ionized gas in galaxies is in a diffuse phase - the so-called Diffuse Ionized Gas (DIG) - and its maintenance represents a significant power requirement for galaxies. In the past fifteen years, it has been found that DIG layers in spirals are suprisingly thick, and the way in which galaxies maintain these thick ionized layers is not well understood. Diagnostic optical emission line ratios suggest that the dominant ionizing source is photo-ionization by the thin disk of massive stars, but there is evidence that additional sources of ionization in these DIG 'halos' is required. The degree to which such sources are necessary, the nature of the sources, and environment-dependent variations all rely on unambiguous ionization diagnostics. Unfortunately, the optical ratios suffer from complications due to gas temperature, abundance and extinction effects. Spitzer offers access to the [Ne III]/[Ne II] ratio - a diagnostic free of all these complications. A successful pilot IRS study of NGC 891 by us showed the feasibility of detecting these lines in faint gaseous halos and already revealed severe difficulties for pure photo-ionization models. However, this study featured only two positions in the halo of a single spiral. Here we propose to extend this study to observe positions in the halos of three nearby edge-on spiral galaxies, where the optical ratios indicate a variety of ionization requirements, allowing more general conclusions to be drawn about the maintenance of DIG layers, as well as the interpretation of the optical ratios. We will compare results with our own state-of-the-art photo-ionization and shock-ionization models. Our pilot study also featured the first spectroscopic detections of PAHs in an external galaxy halo, and the proposed observations will extend our knowledge of the PAH population in halo environments.

  11. Spectral Characteristics of Radiation from the Nucleus of the Seyfert Galaxy NGC 1275 After an Epoch of its Maximum Activity

    NASA Astrophysics Data System (ADS)

    Bikmaev, I. F.; Sharipova, L. M.; Galeev, A. I.; Akhmetkhanova, A. É.

    2016-03-01

    The spectral characteristics of radiation from the nucleus of the Seyfert galaxy NGC 1275 are studied on a long time scale. Changes in the profiles of some emission lines and changes in the relative intensities of hydrogen and forbidden lines and their equivalent widths (EWλ ) are demonstrated on a time scale of decades. These studies employed spectral data obtained with the 1.5-m Russian-Turkish telescope (RTT-150) during January 2012 and drew on spectral data published earlier in the literature. These results made it possible to trace the state of the nucleus of NGC 1275 after an activity maximum that occurred during the 1960's.

  12. A dual velocity in the highly ionized wind of the luminous narrow line Seyfert galaxy PG 1211+143

    NASA Astrophysics Data System (ADS)

    Pounds, K. A.; Lobban, A.; Reeves, J. N.; Vaughan, S.

    2016-05-01

    An extended XMM-Newton observation of the luminous narrow line Seyfert galaxy PG 1211+143 in 2014 has revealed a complex high velocity outflow, with components distinguished in velocity, ionization and short-term variability. We report here the detection of previously unseen spectral structure in Fe K absorption, finding a second velocity component of the highly ionized wind, apparently co-moving with a low ionization flow detected in the soft X-ray spectrum. Comparison with the first observation in 2001 finds a similar outflow energy rate.

  13. The Relativistic Iron Line Profile in the Seyfert 1 Galaxy IC4329a

    NASA Technical Reports Server (NTRS)

    Done, C.; Madejski, G. M.; Zycki, P. T.

    2000-01-01

    We present simultaneous ASCA and RXTE data on the bright Seyfert 1 galaxy IC4329a. The iron line is significantly broadened, but not to the extent expected from an accretion disk which extends down to the last stable orbit around a black hole. We marginally detect a narrow line component, presumably from the molecular torus, but, even including this gives a line profile from the accretion disk which is significantly narrower that that seen in MCG-6-30-15, and is much more like that seen from the low/hard state galactic black hole candidates. This is consistent with the inner disk being truncated before the last stable orbit, forming a hot flow at small radii as in the ADAF models. However. we cannot rule out the presence of an inner disk which does not contribute to the reflected spectrum. either because of extreme ionisation suppressing the characteristic atomic features of the reflected spectrum or because the X-ray source is intrinsically anisotropic, so it does not illuminate the inner disk. The source was monitored by RXTE every 2 days for 2 months, and these snapshot spectra show that there is intrinsic spectral variability. The data are good enough to disentangle the power law from the reflected continuum and we see that the power law softens as the source brightens. The lack of a corresponding increase in the observed reflected spectrum implies that either the changes in disk inner radial extent/ionization structure are small, or that the variability is actually driven by changes in the seed photons which are decoupled from the hard X-ray mechanism.

  14. Ultraviolet and X-ray Variability of the Seyfert 1.5 Galaxy Markarian 817

    NASA Astrophysics Data System (ADS)

    Winter, Lisa M.; Danforth, Charles; Vasudevan, Ranjan; Brandt, W. N.; Scott, Jennifer; Froning, Cynthia; Keeney, Brian; Shull, J. Michael; Penton, Steve; Mushotzky, Richard; Schneider, Donald P.; Arav, Nahum

    2011-02-01

    We present an investigation of the ultraviolet and X-ray spectra of the Seyfert 1.5 galaxy Markarian 817. The ultraviolet analysis includes two recent observations taken with the Cosmic Origins Spectrograph (COS) in 2009 August and December, as well as archival spectra from the International Ultraviolet Explorer and the Hubble Space Telescope. Twelve Lyα absorption features are detected in the 1997 Goddard High Resolution Spectrograph (GHRS) and 2009 COS spectra—of these, four are associated with high-velocity clouds in the interstellar medium, four are at low significance, and the remaining four are intrinsic features, which vary between the GHRS and COS observations. The strongest intrinsic absorber in the 1997 spectrum has a systemic velocity of ~-4250 km s-1. The corresponding feature in the COS data is five times weaker than the GHRS absorber. The three additional weak (equivalent width from 13 to 54 mÅ) intrinsic Lyα absorbers are at systemic velocities of -4100 km s-1, -3550 km s-1, and -2600 km s-1. However, intrinsic absorption troughs from highly ionized C IV and N V are not detected in the COS observations. No ionized absorption signatures are detected in the ~14 ks XMM-Newton EPIC spectra. The factor of five change in the intrinsic Lyα absorber is most likely due to bulk motions in the absorber, since there is no drastic change in the UV luminosity of the source from the GHRS to the COS observations. In a study of the variability of Mrk 817, we find that the X-ray luminosity varies by a factor of ~40 over 20 years, while the UV continuum/emission lines vary by at most a factor of ~2.3 over 30 years. The variability of the X-ray luminosity is strongly correlated with the X-ray power-law index, but no correlation is found with the simultaneous optical/UV photometry.

  15. SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

    SciTech Connect

    Shapovalova, A. I.; Burenkov, A. N.; Popovic, L. C.; Kovacevic, J.; Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L.; Ilic, D.; Kovacevic, A.; Kollatschny, W.; Bochkarev, N. G.; Leon-Tavares, J.; Mercado, A.; Benitez, E.; Dultzin, D.; De la Fuente, E.

    2012-09-15

    We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted H{alpha}, H{beta}, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the H{beta} and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F{sub max}/F{sub min}) of Ark 564 is between 1.5 for H{alpha} and 1.8 for the Fe II lines. The correlation between the Fe II and H{beta} flux variations is of higher significance than that of H{alpha} and H{beta} (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

  16. Measuring key X-ray parameters from simulated spectra of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Bonson, K.; Gallo, L. C.

    2016-05-01

    Supermassive black hole (SMBH) accretion is an important topic of astrophysical research for a variety of fields. However, literature shows that precisely modelling the X-ray reflection component of an accretion disk around a SMBH is challenging. We test how reliably we can measure key active galactic nuclei (AGN) X-ray reflection parameters by simulating the spectra of average Seyfert 1 galaxies and then fitting those spectra using common modelling techniques. The AGN spectra were created from 0.01-300.0 keV using XMM-Newton pn responses and with (3.75±0.10)×106 counts in the 2-10 keV band. The model RELXILL was used to create all spectra with a reflection fraction (ratio of reflected flux over primary flux from 0.1-100 keV) of R = 1. The values of six key parameters were generated randomly within given ranges to simulate the spectra: photon index (Γ), inner emissivity index (q1), black hole spin (a), disk inclination angle (θ), ionization (ξ), and iron abundance in solar units (A_Fe). Once the simulated spectra were created, they were autonomously fit with RELXILL from 2.5-10.0 keV. All six key parameters were allowed to vary throughout the modelling process, with a gradual thawing of model parameters to mimic manual fitting procedure. We find that we can successfully measure key AGN spectral components in this scenario, but some conditions apply: Γ, θ, and A_Fe are well constrained, however they are also consistently overestimated. Only black hole spin (a) measurements that are in extrema, a > 0.9, can be considered reliable. Lastly, ξ and q1 cannot be measured and these parameters - along with intermediate spin values - should be verified using other techniques.

  17. X-Ray Spectral and Temporal Analysis of Narrow Line Seyfert 1 Galaxy Was 61

    NASA Astrophysics Data System (ADS)

    Dou, Liming; Wang, Ting-Gui; Ai, Yanli; Yuan, Weimin; Zhou, Hongyan; Dong, Xiao-Bo

    2016-03-01

    We present an analysis of spectrum and variability of the bright reddened narrow line Seyfert 1 galaxy Was 61 using 90 ks archival XMM-Newton data. The X-ray spectrum in 0.2-10 keV can be characterized by an absorbed power-law plus soft excess and an Fe Kα emission line. The power-law spectral index remains constant during the flux variation. The absorbing material is mildly ionized, with a column density of 3.2 × 1021 cm-2, and does not appear to vary during the period of the X-ray observation. If the same material causes the optical reddening (E(B-V) ≃ 0.6 mag), it must be located outside the narrow line region with a dust-to-gas ratio similar to the average Galactic value. We detect significant variations of the Fe Kα line during the observational period. A broad Fe Kα line at ≃ 6.7 {{keV}} with a width of ˜0.6 keV is detected in the low flux segment of the first 40 ks exposure, and is absent in the spectra of other segments; a narrow Fe Kα emission line ˜6.4 keV with a width of ˜0.1 keV is observed in the subsequent 20 ks segment, which has a count rate 35% higher and is in the next day. We believe this is due to the change in geometry and kinematics of the X-ray emitting corona. The temperature and flux of soft X-ray excess appear to correlate with the flux of the hard power-law component. Comptonization of disc photons by a warm and optically thick inner disk is preferred to interpret the soft excess, rather than the ionized reflection.

  18. Infrared spectroscopy of Seyfert 2 galaxies: A look through the obscuring Torus?

    NASA Technical Reports Server (NTRS)

    Goodrich, Robert W.; Veilleux, Sylvain; Hill, Gary J.

    1994-01-01

    We present both high-resolution (R = 1260) and low-resolution (R = 345 and 425) J-band spectra of a sample of 15 Seyfert 2 galaxies. Our goal is to look for broad Pa beta lines, indicating broad-line regions which are hidden by dust from our view at optical wavelengths. Of the 15 objects studied here, three have broad Pa beta lines: MCG-05.23.16, Mrk 463E, and NGC 2992. Mrk 176 and NGC 5728 may also have weak broad lines. In NGC 5506, previously reported to have broad Pa beta and hydrogen alpha lines, we find that the Pa beta line profile is continuous and has the same shape as the nearby line (Fe II) lambda 1.2567, which should not have a broad component. We interpret these observations as gas from the narrow-line region (NLR) with no broad component. In NGC 5506, however, the NLR profiles become broader with increasing wavelength, indicating that highly reddened wings are becoming more readily visible at the longer wavelengths. We confirm the correlation of (O I) lambda 6300/hydrogen alpha and (Fe II) lambda 1.644/Br gamma (the latter transformed to (Fe II) lambda 1.2567/Pa beta to compare with our data) found by previous authors when comparing active galactic nuclei (AGNs), supernova remnants, starbursts, and H II regions. The correlation confirms that in all of these objects both (O I) lambda 6300 and the (Fe II) lines come from partially ionized regions in which hydrogen is mostly neutral. Comparison of the infrared optical depths with column depths determined from X-ray data show a general tendency for the objects with detected broad Pa beta to have lower X-ray columns.

  19. The origin of the soft X-ray excess in the Seyfert 2 galaxy NGC 2110

    NASA Technical Reports Server (NTRS)

    Weaver, K. A.; Mushotzky, R. F.; Serlemitsos, P. J.; Wilson, A. S.; Elvis, M.; Briel, U.

    1995-01-01

    We present and discuss an X-ray image and a medium-resolution X-ray spectrum of the Seyfert 2 galaxy NGC 2110 obtained with the high-resolution imager (HRI) on ROSAT (0.1-2.4 keV) and Goddard's Broad Band X-ray Telescope (BBXRT; 0.3-11 keV), respectively. Spatially resolved soft X-ray emission, which peaks 4 arcsecs to the north of the nucleus and near the position of the highest excitation optical emission line gas is seen in the HRI observation. The extent has a flux of approximately 3 x 10(exp -13) ergs/sq cm/s and accounts for 11% +/- 3% of the total 0.1-2.4 keV flux. To model the BBXRT spectrum, a soft excess component is required which has a flux of approximately 3.5 x 10(exp -13) ergs/sq cm/s and accounts for approximately 14% +/- 6% of the total 0.1-2.4 keV flux. In addition, BBXRT confirms the presence of an approximately 175 eV equivalent width Fe K alpha flourescence line in NGC 2110. Because of the good agreement between their fluxes, we propose that the soft excess in NGC 2110 is due to leakage of the X-ray continuum through a patchy absorber. The temperature of the gas responsible for the soft excess is too high to be accounted for by local shock heating. In order to explain the soft excess and extent as either scattered continuum X-rays or flourescence from gas photoionized by the nuclear source, the hard X-rays must be emitted anisotropically. However, the soft excess and extent can be well modeled as thermal emission from a hot, outflowing wind, which may also be responsible for confirming at least some portion of the optical narrow line-emitting clouds.

  20. The Far-Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

    NASA Technical Reports Server (NTRS)

    Spinoglio, Luigi; Smith, Howard A.; Gonzalez-Alfonso, Eduardo; Fisher, Jacqueline

    2005-01-01

    We report on the analysis of the first complete far-infrared spectrum (43-197 microns) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO). In addition to the 7 expected ionic fine structure emission lines, the OH rotational lines at 79, 119 and 163 microns were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 micron line, where detected, is always in absorption. The observed line intensities were modelled together with IS0 Short Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the AGN component and the starburst component in the circumnuclear ring of approximately 3kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a big blue bump is ruled out. Based on the instantaneous starburst age of 5 Myr constrained by the Br gamma equivalent width in the starburst ring, and starburst synthesis models of the mid- and far-infrared fine-structure line emission, a low ionization parameter (U=10(exp -3.5)) and low densities (n=100 cm (exp -3)) are derived. Combining the AGN and starburst components, we succeed in modeling the overall UV to far-IR atomic spectrum of SGC 1068, reproducing the line fluxes to within a factor 2.0 on average with a standard deviation of 1.4. The OH 119 micron emission indicates that the line is collisionally excited, and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, non-local, non-LTE radiative transfer models. The models indicate that the bulk of the emission arises from the nuclear region, although some extended contribution from the starburst is not ruled out. The OH abundance

  1. Line profile and continuum variability in the very broad-line Seyfert galaxy Mrk 926

    NASA Astrophysics Data System (ADS)

    Kollatschny, W.; Zetzl, M.

    2010-11-01

    Aims: We present results of an intensive spectroscopic variability campaign of the very broad-line Seyfert 1 galaxy Mrk 926. Our aim is to investigate the broad-line region (BLR) by studying the intensity and line profile variations of this galaxy on short timescales. Methods: High signal-to-noise ratio (S/N) spectra were taken with the 9.2 m Hobby-Eberly Telescope (HET) in identical conditions during two observing campaigns in 2004 and 2005. After the spectral reduction and internal calibration we achieved a relative flux accuracy of better than 1%. Results: The rms profiles of the very broad Balmer lines have shapes that differ from their mean line profiles, consisting of two inner (v ≲ ± 6000 km s-1) and two outer (v ≳ ± 6000 km s-1) line components in addition to a central component (v ≲ ± 600 km s-1). These outer and inner line segments varied with different amplitudes during our campaign. The radius of the BLR is very small with an upper limit of 2 light-days for the Hβ BLR size. We derived an upper limit to the central black hole mass of M = 11.2 × 107 M⊙. The 2-D cross-correlation functions CCF(τ, v) of Hβ and Hα are flat within the error limits. The response of the Balmer line segments with respect to continuum variations is different in the outer and inner wings of Hα and Hβ. This double structure in the response curves - of two separate inner and outer components - has also been seen in the rms line profiles. We conclude that the outer and inner line segments originate in different regions and/or under different physical conditions. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  2. A Sample of Seyfert-2 Galaxies with Ultraluminous Galaxy-wide Narrow-line Regions: Quasar Light Echoes?

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Diaz, R.; Holhjem, K.; Levenson, N. A.; Winge, C.

    2013-01-01

    We report the discovery of Seyfert-2 galaxies in SDSS-DR8 with galaxy-wide, ultraluminous narrow-line regions (NLRs) at redshifts z = 0.2-0.6. With a space density of 4.4 Gpc-3 at z ~ 0.3, these "green beans" (GBs) are amongst the rarest objects in the universe. We are witnessing an exceptional and/or short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). The main focus of this paper is on a detailed analysis of the GB prototype galaxy J2240-0927 (z = 0.326). Its NLR extends over 26 × 44 kpc and is surrounded by an extended NLR. With a total [O III] λ5008 luminosity of (5.7 ± 0.9) × 1043 erg s-1, this is one of the most luminous NLRs known around any type-2 galaxy. Using VLT/XSHOOTER, we show that the NLR is powered by an AGN, and we derive resolved extinction, density, and ionization maps. Gas kinematics is disturbed on a global scale, and high-velocity outflows are absent or faint. This NLR is unlike any other NLR or extended emission line region known. Spectroscopy with Gemini/GMOS reveals extended, high-luminosity [O III] emission also in other GBs. WISE 24 μm luminosities are 5-50 times lower than predicted by the [O III] fluxes, suggesting that the NLRs reflect earlier, very active quasar states that have strongly subsided in less than a galaxy's light-crossing time. These light echoes, or ionization echoes, are about 100 times more luminous than any other such echo known to date. X-ray data are needed for photoionization modeling and to verify the light echoes. Based on observations made with ESO Telescopes at the La Silla and Paranal Observatories, Chile. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. Based on observations

  3. The extended disc and halo of the Andromeda galaxy observed with Spitzer-IRAC

    NASA Astrophysics Data System (ADS)

    Rafiei Ravandi, Masoud; Barmby, Pauline; Ashby, Matthew L. N.; Laine, Seppo; Davidge, T. J.; Zhang, Jenna; Bianchi, Luciana; Babul, Arif; Chapman, S. C.

    2016-06-01

    We present the first results from an extended survey of the Andromeda galaxy (M31) using 41.1 h of observations by Spitzer-IRAC at 3.6 and 4.5 µm. This survey extends previous observations to the outer disc and halo, covering total lengths of 4.4° and 6.6° along the minor and major axes, respectively. We have produced surface brightness profiles by combining the integrated light from background-corrected maps with stellar counts from a new catalogue of point sources. Using auxiliary catalogues, we have carried out a statistical analysis in colour-magnitude space to discriminate M31 objects from foreground Milky Way stars and background galaxies. The catalogue includes 426 529 sources, of which 66 per cent have been assigned probability values to identify M31 objects with magnitude depths of [3.6] = 19.0 ± 0.2, [4.5] = 18.7 ± 0.2. We discuss applications of our data for constraining the stellar mass and characterizing point sources in the outer radii.

  4. TORUS AND ACTIVE GALACTIC NUCLEUS PROPERTIES OF NEARBY SEYFERT GALAXIES: RESULTS FROM FITTING INFRARED SPECTRAL ENERGY DISTRIBUTIONS AND SPECTROSCOPY

    SciTech Connect

    Alonso-Herrero, Almudena; Ramos Almeida, Cristina; Mason, Rachel; Asensio Ramos, Andres; Rodriguez Espinosa, Jose Miguel; Perez-Garcia, Ana M.; Roche, Patrick F.; Levenson, Nancy A.; Elitzur, Moshe; Packham, Christopher; Young, Stuart; Diaz-Santos, Tanio

    2011-08-01

    We used the CLUMPY torus models and a Bayesian approach to fit the infrared spectral energy distributions and ground-based high angular resolution mid-infrared spectroscopy of 13 nearby Seyfert galaxies. This allowed us to put tight constraints on torus model parameters such as the viewing angle i, the radial thickness of the torus Y, the angular size of the cloud distribution {sigma}{sub torus}, and the average number of clouds along radial equatorial rays N{sub 0}. We found that the viewing angle i is not the only parameter controlling the classification of a galaxy into type 1 or type 2. In principle, type 2s could be viewed at any viewing angle i as long as there is one cloud along the line of sight. A more relevant quantity for clumpy media is the probability for an active galactic nucleus (AGN) photon to escape unabsorbed. In our sample, type 1s have relatively high escape probabilities, P{sub esc} {approx} 12%-44%, while type 2s, as expected, tend to have very low escape probabilities. Our fits also confirmed that the tori of Seyfert galaxies are compact with torus model radii in the range 1-6 pc. The scaling of the models to the data also provided the AGN bolometric luminosities L{sub bol}(AGN), which were found to be in good agreement with estimates from the literature. When we combined our sample of Seyfert galaxies with a sample of PG quasars from the literature to span a range of L{sub bol}(AGN) {approx} 10{sup 43}-10{sup 47} erg s{sup -1}, we found plausible evidence of the receding torus. That is, there is a tendency for the torus geometrical covering factor to be lower (f{sub 2} {approx} 0.1-0.3) at high AGN luminosities than at low AGN luminosities (f{sub 2} {approx} 0.9-1 at {approx}10{sup 43}-10{sup 44} erg s{sup -1}). This is because at low AGN luminosities the tori appear to have wider angular sizes (larger {sigma}{sub torus}) and more clouds along radial equatorial rays. We cannot, however, rule out the possibility that this is due to

  5. Origin of the broad iron line feature and the soft X-ray variation in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Iso, Naoki; Ebisawa, Ken; Sameshima, Hiroaki; Mizumoto, Misaki; Miyakawa, Takehiro; Inoue, Hajime; Yamasaki, Hiroki

    2016-06-01

    Many Seyfert galaxies are known to exhibit significant X-ray spectral variations and seemingly broad iron K-emission line features. In this paper, we show that the "variable partial covering model," which has been successfully proposed for MCG -6-30-15 (Miyakawa et al. 2012, PASJ, 64, 140) and 1H 0707-495 (Mizumoto et al. 2014, PASJ, 66, 122), can also explain the spectral variations in 2-10 keV as well as the broad iron line features in 20 other Seyfert galaxies observed with Suzaku. In this model, the absorbed spectral component through the optically thick absorbing clouds has a significant iron K-edge, which primarily accounts for the observed, seemingly broad iron line feature. Fluctuation of the absorbing clouds in the line of sight of the extended X-ray source results in variation of the partial covering fraction, which causes an anti-correlation between the direct (not covered) spectral component and the absorbed (covered) spectral component below ˜10 keV. Observed spectral variation in 2-10 keV in a timescale of less than ˜1 day is primarily explained by such variations of the partial covering fraction, while the intrinsic soft X-ray luminosity is hardly variable.

  6. Spitzer Survey of the Large Magellanic Cloud: Surveying the Agents of a Galaxy's Evolution (SAGE)

    NASA Astrophysics Data System (ADS)

    Meixner, Margaret; Babler, Brian; Bernard, Jean-Philippe; Blum, Robert; Boulanger, Francois; Churchwell, Edward; Cohen, Martin; Engelbracht, Charles; Frogel, Jay; Fukui, Yasuo; Gallagher, Jay; Gordon, Karl; Gorjian, Varoujan; Harris, Jason; Hora, Joseph; Indebetouw, Remy; Jansen, Stephen; Kawamura, Akiko; Kelly, Douglas; Kemper, Ciska; Latter, William; Leitherer, Claus; Madden, Suzanne; Meade, Marilyn; Misselt, Karl; Mizuno, Norikazu; Mizuno, Akira; Mould, Jeremy; Nota, Antonella; Oey, Sally; Olsen, Knut; Onishi, Toshikazu; Paladini, Roberta; Panagia, Nino; Perez-Gonzalez, Pablo; Reach, William; Shibai, Hiroshi; Shuji, Sato; Smith, Linda; Staveley-Smith, Lister; Tielens, Xander; Ueta, Toshiya; van Dyk, Schuyler; Volk, Kevin; Werner, Michael; Whitney, Barbara; Zaritsky, Dennis

    2005-06-01

    The recycling of matter between the interstellar medium (ISM) and stars drives the evolution of a galaxy's visible matter. To understand this recycling, we propose to study the physical processes of the ISM, the formation of new stars and the injection of mass by evolved stars and their relationships on the galaxy-wide scale of the Large Magellanic Cloud (LMC). Due to its proximity, favorable viewing angle, multi-wavelength information, and measured tidal interactions with the Milky Way (MW) and Small Magellanic Cloud (SMC), the LMC is uniquely suited for surveying the agents of a galaxy's evolution (SAGE), the ISM and stars. Our uniform and unbiased survey of the LMC (7x7 degrees) in all IRAC and MIPS bands will have much better wavelength coverage, up to ~1000 times better point source sensitivity and ~11 times better angular resolution than previous IR surveys. Full and uniform coverage of the LMC is necessary to study the galaxy as a system, to develop a template for more distant galaxies and to create an archival data set (rights waived) that promises a lasting legacy to match current LMC surveys at other wavelengths. SAGE will reveal over 6 million sources including ~150,000 evolved stars, ~50,000 young stellar objects and the diffuse ISM with column densities >1.2e21 H/cm2. In contrast to the MW and SMC, the diffuse IR emission in the LMC can be unambiguously associated with individual gas/dust clouds, thereby permitting unique studies of dust processes in the ISM. SAGE's complete census of newly formed stars with masses >1-3 Msun will reveal whether tidally-triggered star formation events in the LMC are sustained or short-lived. SAGE's complete census of evolved stars with mass loss rates >1e-8 Msun/yr will quantitatively measure the rate at which evolved stars inject mass into the ISM. SAGE will be the crucial link between Spitzer's survey of individual IR sources in the MW (GLIMPSE) and its surveys of galaxies (e.g., SINGS) and a stepping stone to the

  7. Kinematical evidence for secular evolution in Spitzer Survey of Stellar Structure in Galaxies (S4G) spirals

    NASA Astrophysics Data System (ADS)

    Erroz-Ferrer, Santiago; Knapen, Johan H.; Font, Joan; Beckman, John E.

    2015-03-01

    We present a study of the kinematics of a sample of isolated spiral galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We use Hα Fabry-Perot data from the GHαFaS instrument at the William Herschel Telescope (WHT) in La Palma, complemented with images at 3.6 microns, in the R band and in the Hα filter. The resulting data cubes and velocity field maps allow a complete study of the kinematics of a galaxy, including in-depth investigations of the rotation curve, velocity moment maps, velocity residual maps, gradient maps and position-velocity (PV) diagrams. We find clear evidence of the secular evolution processes going on in these galaxies, such as asymmetries in the velocity field in the bar zone, and non-circular motions, probably in response to the potential of the structural components of the galaxies, or to past or present interactions.

  8. Discovery of the X-ray transient Narrow-Line Seyfert 1 Galaxy WPVS 007 in a very low optical/UV flux state detected by Swift.

    NASA Astrophysics Data System (ADS)

    Grupe, Dirk; Komossa, S.; Leighly, Karen; Terndrup, Don

    2015-06-01

    We report on the lowest flux state in the optical/UV of the Narrow Line Seyfert 1 galaxy WPVS 007 (RA-2000: 00 39 15.8, Dec-2000: -51 17 01, z=0.02861) since we started monitoring this AGN in the optical and UV in October 2005.

  9. Studying the Iron Line Complex in the Bright Seyfert Galaxy NGC 5506

    NASA Technical Reports Server (NTRS)

    Nicastro, Fabrizio; Atkins, Patricia M. (Technical Monitor)

    2002-01-01

    This grant was to support the reduction and analysis of our approved XMM observation of the nearby Seyfert 2 galaxy NGC 5506. The observation has been carried out simultaneously with a BeppoSAX observation of the same source. The proposal was aimed to study in detail the Compton reflection component and the complex Iron K line of this source, combining the still unique capability of BeppoSAX in hard X-rays (to strongly constrain the reflection component, and then the intrinsic nuclear continuum), and the sensitivity of XMM at the energy of the Iron Line complex. NGC 5506 is one of the brightest AGN in hard X-rays and has been intensively studied in the past. GINGA detected the complex iron line as well as the reflection component. Both ASCA (spectroscopically) and Rossi-XTE (through variability analysis) suggested that the FeK line is complex, possibly made up of several distinct components. The centroid of the FeK complex in a subsequent BeppoSAX observation was bluer than the 6.4 keV energy of the relatively low-ionization iron Kalpha transition. NGC 5506 has been observed simultaneously by NewtonXMM and BeppoSAX on February 2-3 2001. we have reduced and analyzed both the NewtonXMM and the BeppoSAX data, and have written and published a paper on our results (appeared in Volume 377 (page 31) of A&A-Letters). Our main results can be summarized as follows: (a) we confirm that the FeK line is complex, and for the first time disentangle its components: we find that at least two components made up the FeK complex, one neutral and narrow, at 6.4 keV (rest energy), and another one either broader and highly ionized, at about 6.7 keV (rest frame), or, in turn, made up of two narrow and unresolved components from the He-like and the H-like ions of Fe; (b) the two possible solution for the high-ionization Fe-K component, are statistically indistinguishable. However, physically, a blend of two narrow lines from photoionized matter seems to be preferable to emission of a

  10. FIREWORKS NEAR A BLACK HOLE IN THE CORE OF SEYFERT GALAXY NGC 4151

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Space Telescope Imaging Spectrograph (STIS) simultaneously records, in unprecedented detail, the velocities of hundreds of gas knots streaming at hundreds of thousands of miles per hour from the nucleus of NGC 4151, thought to house a supermassive black hole. This is the first time the velocity structure in the heart of this object, or similar objects, has been mapped so vividly this close to its central black hole. The twin cones of gas emission are powered by the energy released from the supermassive black hole believed to reside at the heart of this Seyfert galaxy. The STIS data clearly show that the gas knots illuminated by one of these cones is rapidly moving towards us, while the gas knots illuminated by the other cone are rapidly receding. The images have been rotated to show the same orientation of NGC 4151. The figures show: WFPC2 (upper left) -- A Hubble Wide Field Planetary Camera 2 image of the oxygen emission (5007 Angstroms) from the gas at the heart of NGC 4151. Though the twin cone structure can be seen, the image does not provide any information about the motion of the oxygen gas. STIS OPTICAL (upper right) -- In this STIS spectral image of the oxygen gas, the velocities of the knots are determined by comparing the knots of gas in the stationary WFPC2 image to the horizontal location of the knots in the STIS image. STIS OPTICAL (lower right) -- In this false color image the two emission lines of oxygen gas (the weaker one at 4959 Angstroms and the stronger one at 5007 Angstroms) are clearly visible. The horizontal line passing through the image is from the light generated by the powerful black hole at the center of NGC 4151. STIS ULTRAVIOLET (lower left) -- This STIS spectral image shows the velocity distribution of the carbon emission from the gas in the core of NGC 4151. It requires more energy to make the carbon gas glow (CIV at 1549 Angstroms) than it does to ionize the oxygen gas seen in the other images. This means we expect that the

  11. JET PROPERTIES OF GeV-SELECTED RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES AND POSSIBLE CONNECTION TO THEIR DISK AND CORONA

    SciTech Connect

    Sun, Xiao-Na; Lin, Da-Bin; Liang, En-Wei; Zhang, Jin; Xue, Zi-Wei; Zhang, Shuang-Nan

    2015-01-01

    The observed spectral energy distributions of five GeV-selected narrow-line Seyfert 1 (NLS1) galaxies are fitted with a model including the radiation ingredients from the relativistic jet, the accretion disk, and the corona. We compare the properties of these GeV NLS1 galaxies with flat spectrum radio quasars (FSRQs), BL Lacertae objects (BL Lacs), and radio-quiet (RQ) Seyfert galaxies, and explore possible hints for jet-disk/corona connection. Our results show that the radiation physics and the jet properties of the GeV NLS1 galaxies resemble that of FSRQs. The luminosity variations of PMN J0948+0022 and 1H 0323+342 at the GeV band is tightly correlated with the beaming factor (δ), similar to that observed in FSRQ 3C 279. The accretion disk luminosities and the jet powers of the GeV NLS1 galaxies cover both the ranges of FSRQs and BL Lacs. With the detection of bright corona emission in 1H 0323+342, we show that the ratio of the corona luminosity (L {sub corona}) to the accretion disk luminosity (L {sub d}) is marginally within the high end of this ratio distribution for an RQ Seyfert galaxy sample, and the variation of jet luminosity may connect with L {sub corona}. However, it is still unclear whether a system with a high L {sub corona}/L {sub d} ratio prefers to power a jet.

  12. EARLY-TYPE GALAXIES WITH TIDAL DEBRIS AND THEIR SCALING RELATIONS IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

    SciTech Connect

    Kim, Taehyun; Sheth, Kartik; Munoz-Mateos, Juan-Carlos; Lee, Myung Gyoon; Gadotti, Dimitri A.; Knapen, Johan H.; Schinnerer, Eva; Ho, Luis C.; Madore, Barry F.; Laurikainen, Eija; Salo, Heikki; Athanassoula, E.; Bosma, Albert; Comeron, Sebastien; Regan, Michael W.; Menendez-Delmestre, Karin; De Paz, Armando Gil; and others

    2012-07-01

    Tidal debris around galaxies can yield important clues on their evolution. We have identified tidal debris in 11 early-type galaxies (T {<=} 0) from a sample of 65 early types drawn from the Spitzer Survey of Stellar Structure in Galaxies (S{sup 4}G). The tidal debris includes features such as shells, ripples, and tidal tails. A variety of techniques, including two-dimensional decomposition of galactic structures, were used to quantify the residual tidal features. The tidal debris contributes {approx}3%-10% to the total 3.6 {mu}m luminosity of the host galaxy. Structural parameters of the galaxies were estimated using two-dimensional profile fitting. We investigate the locations of galaxies with tidal debris in the fundamental plane and Kormendy relation. We find that galaxies with tidal debris lie within the scatter of early-type galaxies without tidal features. Assuming that the tidal debris is indicative of recent gravitational interaction or merger, this suggests that these galaxies have either undergone minor merging events so that the overall structural properties of the galaxies are not significantly altered, or they have undergone a major merging events but already have experienced sufficient relaxation and phase mixing so that their structural properties become similar to those of the non-interacting early-type galaxies.

  13. The continuum of type 1 Seyfert galaxies. I - A single form modified by the effects of dust

    NASA Technical Reports Server (NTRS)

    Ward, Martin; Elvis, Martin; Fabbiano, G.; Carleton, N. P.; Willner, S. P.

    1987-01-01

    Broad-band measurements from 1 to 20 microns of 26 emission-line active galactic nuclei (AGNs), mainly Seyfert 1 galaxies, have been made. These data have been combined with previous optical and infrared photometry and IRAS 12, 25, 60 and 100 micron fluxes, giving a total sample of 37 AGNs, all of which have hard X-ray measurements. The sample includes all the emission-line AGNs identified in the Piccinotti et al. (1982) survey. When corrected for stellar contributions in the near-infrared, the continuum energy distributions can be classified observationally into three types: (1) bare, minimally reddened AGNs; (2) reddened AGNs; and (3) AGNs for which the far-infrared emission is contaminated by the host galaxy. These classifications reflect a range of luminosities and different environments rather than intrinsic differences in the primary continuum of the AGNs. The data are consistent with a single underlying form of active galaxy continuum modified by the presence of dust and of the host galaxy.

  14. The Penrose photoproduction scenario for NGC 4151: A black hole gamma-ray emission mechanism for active galactic nuclei and Seyfert galaxies. [Compton scattering and pair production

    NASA Technical Reports Server (NTRS)

    Leiter, D.

    1979-01-01

    A consistent theoretical interpretation is given for the suggestion that a steepening of the spectrum between X-ray and gamma ray energies may be a general, gamma-ray characteristic of Seyfert galaxies, if the diffuse gamma ray spectrum is considered to be a superposition of unresolved contributions, from one or more classes of extragalactic objects. In the case of NGC 4151, the dominant process is shown to be Penrose Compton scattering in the ergosphere of a Kerr black hole, assumed to exist in the Seyfert's active galactic nucleus.

  15. A Spitzer High-resolution Mid-Infrared Spectral Atlas of Starburst Galaxies

    NASA Astrophysics Data System (ADS)

    Bernard-Salas, J.; Spoon, H. W. W.; Charmandaris, V.; Lebouteiller, V.; Farrah, D.; Devost, D.; Brandl, B. R.; Wu, Yanling; Armus, L.; Hao, L.; Sloan, G. C.; Weedman, D.; Houck, J. R.

    2009-10-01

    We present an atlas of Spitzer/IRS high-resolution (R ~ 600) 10-37 μm spectra for 24 well known starburst galaxies. The spectra are dominated by fine-structure lines, molecular hydrogen lines, and emission bands of polycyclic aromatic hydrocarbons (PAHs). Six out of the eight objects with a known active galactic nucleus (AGN) component show emission of the high excitation [Ne V] line. This line is also seen in one other object (NGC 4194) with, a priori, no known AGN component. In addition to strong PAH emission features in this wavelength range (11.3, 12.7, 16.4 μm), the spectra reveal other weak hydrocarbon features at 10.6, 13.5, 14.2 μm, and a previously unreported emission feature at 10.75 μm. An unidentified absorption feature at 13.7 μm is detected in many of the starbursts. We use the fine-structure lines to derive the abundance of neon and sulfur for 14 objects where the H I 7-6 line is detected. We further use the molecular hydrogen lines to sample the properties of the warm molecular gas. Several basic diagrams characterizing the properties of the sample are also shown. We have combined the spectra of all the pure starburst objects to create a high signal-to-noise ratio template, which is available to the community.

  16. A SPITZER HIGH-RESOLUTION MID-INFRARED SPECTRAL ATLAS OF STARBURST GALAXIES

    SciTech Connect

    Bernard-Salas, J.; Spoon, H. W. W.; Lebouteiller, V.; Farrah, D.; Wu, Yanling; Hao, L.; Sloan, G. C.; Weedman, D.; Houck, J. R.; Charmandaris, V.; Devost, D.; Brandl, B. R.; Armus, L.

    2009-10-01

    We present an atlas of Spitzer/IRS high-resolution (R {approx} 600) 10-37 {mu}m spectra for 24 well known starburst galaxies. The spectra are dominated by fine-structure lines, molecular hydrogen lines, and emission bands of polycyclic aromatic hydrocarbons (PAHs). Six out of the eight objects with a known active galactic nucleus (AGN) component show emission of the high excitation [Ne V] line. This line is also seen in one other object (NGC 4194) with, a priori, no known AGN component. In addition to strong PAH emission features in this wavelength range (11.3, 12.7, 16.4 {mu}m), the spectra reveal other weak hydrocarbon features at 10.6, 13.5, 14.2 {mu}m, and a previously unreported emission feature at 10.75 {mu}m. An unidentified absorption feature at 13.7 {mu}m is detected in many of the starbursts. We use the fine-structure lines to derive the abundance of neon and sulfur for 14 objects where the H I 7-6 line is detected. We further use the molecular hydrogen lines to sample the properties of the warm molecular gas. Several basic diagrams characterizing the properties of the sample are also shown. We have combined the spectra of all the pure starburst objects to create a high signal-to-noise ratio template, which is available to the community.

  17. An XMM-Newton Observation of the Seyfert Galaxy 1H0419-577 in an Extreme Low State

    NASA Technical Reports Server (NTRS)

    Pounds, K. A.; Reeves, J. N.; Page, K. L.; O'Brien, P. T.

    2003-01-01

    Previous observations of the luminous Seyfert galaxy 1H 0419-577 have found its X-ray spectrum to range from that of a typical Seyfert 1 with 2-10 keV power law index Gamma approx. 1.9 to a much flatter power law of Gamma approx. 1.5 or less. We report here a new XMM-Newton observation which allows the low state spectrum to be studied in much greater detail than hitherto. We find a very hard spectrum (Gamma approx. 1.0) which exhibits broad features that can be modelled with the addition of an extreme relativistic Fe K emission line or with partial covering of the underlying continuum by a substantial column density of near-neutral gas. Both the EPIC and RGS data show evidence for strong line emission of OVII and OVIII requiring an extended region of low density photoionised gas in 1H 0419- 577. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was X-ray bright indicates the dominant spectral variability occurs via a steep power law component.

  18. An XMM-Newton Observation of the Seyfert 1 Galaxy 1H 0419-577 in an Extreme Low State

    NASA Technical Reports Server (NTRS)

    Pounds, K. A.; Reeves, J. N.; Page, K. L.; OBrien, P. T.

    2004-01-01

    Previous observations of the luminous Seyfert 1 galaxy 1H 0419-577 have found its X-ray spectrum to range from that of a typical Seyfert 1 with 2-10 keV power law index Gamma approx. 1.9 to a much flatter power law of Gamma approx. 1.5 or less. We report here a new XMM-Newton observation which allows the low state spectrum to be studied in much greater detail than hitherto. We find a very hard spectrum (Gamma approx. 1.0), which exhibits broad features that can be modelled myth the addition of an extreme relativistic Fe K emission line or with partial covering of the underlying continuum by a substantial column density of near-neutral gas. Both the EPIC and RGS data show evidence for strong line emission of OVII and OVIII requiring an extended region of low density photoionised gas in 1H 0419-577. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was 'X-ray bright' indicates the dominant spectral variability occurs via a steep power law component.

  19. X-ray observations of the Seyfert 1 galaxies AKN120 and MCG8-11-11

    NASA Technical Reports Server (NTRS)

    Mushotzky, R.; Marshall, F. E.

    1980-01-01

    A new X-ray source, H0523-00, with the optically variable Seyfert 1 galaxy AKN 120 is identified. The source has a 2-10 keV X-ray flux of 2 x 10 to the -11th ergs/sq cm s which corresponds to a 2-10 keV X-ray luminosity of 10 to the 44th ergs/s. X-ray observations over a 1.5 year time span combined with contemporaneous optical photometry show a decrease in the optical with no corresponding decrease in the X-ray. In contrast, similar observations of MCG 8-11-11 show a contemporaneous decrease in optical and X-ray fluxes. It is noted that the infrared and X-ray spectral slopes for these two objects are similar, with the optical being steeper by roughly one unit.

  20. Rapid X-ray variability in the Seyfert galaxy NGC 6814. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Tennant, A. F.; Mushotzky, R. F.; Boldt, E. A.; Swank, J. H.

    1981-01-01

    The HEAO-1 A-2 high time resolution X-ray observations of the X-ray emitting Seyfert I Galaxy NGC 6814 are reported. In sharp distinction with a sample of over 30 active galactic nuclei this object showed strong X-ray variability on timescales less than 3 hours. The mean flux on a timescale of 90 minutes varied by a factor of approximately 2.5 corresponding to Delta L sub x being approximately 1 x 10 to the 43rd power ergs/sec. An autocorrelation analysis shows a characteristic time for variability of 100 (+60 or -25) seconds. There is no indication of spectral variability with an upper limit on a change in the power law spectral index of the absolute value of Delta gamma .37, for a factor two change in intensity. The constraints of such rapid variability on a wide variety of X-ray source mechanisms are considered.

  1. The Two-Phase, Two-Velocity Ionized Absorber in the Seyfert 1 Galaxy NGC 5548

    NASA Astrophysics Data System (ADS)

    Andrade-Velázquez, Mercedes; Krongold, Yair; Elvis, Martin; Nicastro, Fabrizio; Brickhouse, Nancy; Binette, Luc; Mathur, Smita; Jiménez-Bailón, Elena

    2010-03-01

    We present an analysis of X-ray high-quality grating spectra of the Seyfert 1 galaxy NGC 5548 using archival Chandra-High Energy Transmission Grating Spectrometer and Low Energy Transmission Grating Spectrometer observations for a total exposure time of 800 ks. The continuum emission (between 0.2 keV and 8 keV) is well represented by a power law (Γ = 1.6) plus a blackbody component (kT = 0.1 keV). We find that the well-known X-ray warm absorber (WA) in this source consists of two different outflow velocity systems. One absorbing system has a velocity of -1110 ± 150 km s-1 and the other of -490 ± 150 km s-1. Recognizing the presence of these kinematically distinct components allows each system to be fitted independently, each with two absorption components with different ionization levels. The high-velocity system consists of two components, one with a temperature of 2.7 ± 0.6 × 106 K, log U = 1.23, and another with a temperature of 5.8 ± 1.0 × 105 K, log U = 0.67. The high-velocity, high-ionization component produces absorption by charge states Fe XXI-XXIV, while the high-velocity, low-ionization component produces absorption by Ne IX-X, Fe XVII-XX, and O VII-VIII. The low-velocity system also required two absorbing components, one with a temperature of 5.8 ± 0.8 × 105 K, log U = 0.67, producing absorption by Ne IX-X, Fe XVII-XX, and O VII-VIII, and the other with a lower temperature of 3.5 ± 0.35 × 104 K and a lower ionization of log U = -0.49, producing absorption by O VI-VII and the Fe VII-XII M-shell Unresolved Transitions Array. Once these components are considered, the data do not require any further absorbers. In particular, a model consisting of a continuous radial range of ionization structures (as suggested by a previous analysis) is not required. The two absorbing components in each velocity system are in pressure equilibrium with each other. This suggests that each velocity system consists of a multi-phase medium. This is the first time that

  2. Spectra of High-Ionization Seyfert 1 Galaxies: Implications for the Narrow-Line Region

    NASA Technical Reports Server (NTRS)

    Moore, David; Cohen, Ross D.; Marcy, Geoffrey W.

    1996-01-01

    We present line profiles and profile parameters for the Narrow-Line Regions (NLRs) of six Seyfert 1 galaxies with high-ionization lines: MCG 8-11-11, Mrk 79, Mrk 704, Mrk 841, NGC 4151, and NGC 5548. The sample was chosen primarily with the goal of obtaining high-quality [Fe VII] lambda6087 and, when possible, [Fe X] lambda6374 profiles to determine if these lines are more likely formed in a physically distinct 'coronal line region' or are formed throughout the NLR along with lines of lower critical density (n(sub cr)) and/or Ionization Potential (IP). We discuss correlations of velocity shift and width with n(sub cr) and IP. In some objects, lines of high IP and/or n(sub cr) are systematically broader than those of low IP/n(sub cr). Of particular interest, however, are objects that show no correlations of line width with either IP or n(sub cr). In these objects, lines of high and low IP/n(sub cr), are remarkably similar, which is difficult to reconcile with the classical picture of the NLR, in which lines of high and low IP/n(sub cr) are formed in physically distinct regions. We argue for similar spatial extents for the flux in lines with similar profiles. Here, as well as in a modeling-oriented companion paper, we develop further an idea suggested by Moore & Cohen that objects that do and do not show line width correlations with IP/n(sub cr) can both be explained in terms of a single NLR model with only a small difference in the cloud column density distinguishing the two types of object. Overall, our objects do not show correlations between the Full Width at Half-Maximum (FWHM) and IP and/or n(sub cr). The width must be defined by a parameter that is sensitive to extended profile wings in order for the correlations to result. We present models in which FWHM correlations with IP and/or n(sub cr) result only after simulating the lower spectral resolution used in previous observational studies. The models that simulate the higher spectral resolution of our

  3. Spectra of High-Ionization Seyfert 1 Galaxies: Implications for the Narrow-Line Region

    NASA Astrophysics Data System (ADS)

    Moore, David; Cohen, Ross D.; Marcy, Geoffrey W.

    1996-10-01

    We present line profiles and profile parameters for the narrow-line regions (NLRs) of six Seyfert I galaxies with high-ionization lines: MCG 8-11-I1, Mrk 79, Mrk 704, Mrk 841, NGC 4151, and NGC 5548. The sample was chosen primarily with the goal of obtaining high-quality [Fe VII] λ6087 and, when possible, [Fe X] λ6374 profiles to determine if these lines are more likely formed in a physically distinct coronal line region" or are formed throughout the NLR along with lines of lower critical density (n_cr_) and/or ionization potential (IP). We discuss correlations of velocity shift and width with n_cr_ and IP. In some objects, lines of high IP and/or n_cr_ are systematically broader than those of low IP/n_cr_. Of particular interest, however, are objects that show no correlations of line width with either IP or n_cr_ In these objects, lines of high and low IP/n_cr_ are remarkably similar, which is difficult to reconcile with the classical picture of the NLR, in which lines of high and low IP/n_cr_ are formed in physically distinct regions. We argue for similar spatial extents for the flux in lines with similar profiles. Here, as well as in a modeling-oriented companion paper (Paper II), we develop further an idea suggested by Moore & Cohen that objects that do and do not show line width correlations with IP/n_cr_ can both be explained in terms of a single NLR model with only a small difference in the cloud column density distinguishing the two types of object. Overall, our objects do not show correlations between the full width at half- maximum (FWHM) and IP and/or n_cr_. The width must be defined by a parameter that is sensitive to extended profile wings in order for the correlations to result. In Paper II, we present models in which FWHM correlations with IP and/or n_cr_ result only after simulating the lower spectral resolution used in previous observational studies. The models that simulate the higher spectral resolution of our observational study produce line

  4. THE TWO-PHASE, TWO-VELOCITY IONIZED ABSORBER IN THE SEYFERT 1 GALAXY NGC 5548

    SciTech Connect

    Andrade-Velazquez, Mercedes; Krongold, Yair; Binette, Luc; Jimenez-Bailon, Elena; Elvis, Martin; Nicastro, Fabrizio; Brickhouse, Nancy; Mathur, Smita

    2010-03-10

    We present an analysis of X-ray high-quality grating spectra of the Seyfert 1 galaxy NGC 5548 using archival Chandra-High Energy Transmission Grating Spectrometer and Low Energy Transmission Grating Spectrometer observations for a total exposure time of 800 ks. The continuum emission (between 0.2 keV and 8 keV) is well represented by a power law (GAMMA = 1.6) plus a blackbody component (kT = 0.1 keV). We find that the well-known X-ray warm absorber (WA) in this source consists of two different outflow velocity systems. One absorbing system has a velocity of -1110 +- 150 km s{sup -1} and the other of -490 +- 150 km s{sup -1}. Recognizing the presence of these kinematically distinct components allows each system to be fitted independently, each with two absorption components with different ionization levels. The high-velocity system consists of two components, one with a temperature of 2.7 +- 0.6 x 10{sup 6} K, log U = 1.23, and another with a temperature of 5.8 +- 1.0 x 10{sup 5} K, log U = 0.67. The high-velocity, high-ionization component produces absorption by charge states Fe XXI-XXIV, while the high-velocity, low-ionization component produces absorption by Ne IX-X, Fe XVII-XX, and O VII-VIII. The low-velocity system also required two absorbing components, one with a temperature of 5.8 +- 0.8 x 10{sup 5} K, log U = 0.67, producing absorption by Ne IX-X, Fe XVII-XX, and O VII-VIII, and the other with a lower temperature of 3.5 +- 0.35 x 10{sup 4} K and a lower ionization of log U = -0.49, producing absorption by O VI-VII and the Fe VII-XII M-shell Unresolved Transitions Array. Once these components are considered, the data do not require any further absorbers. In particular, a model consisting of a continuous radial range of ionization structures (as suggested by a previous analysis) is not required. The two absorbing components in each velocity system are in pressure equilibrium with each other. This suggests that each velocity system consists of a multi

  5. Spectroscopic Observations of Steep Spectrum Narrow-Line Seyfert 1 Galaxies

    NASA Technical Reports Server (NTRS)

    Leighly, Karen

    1999-01-01

    ROSAT observations of narrow-line Seyfert 1s found consistently steep spectra and rapid variability, but ASCA observations show more diversity, very different to classical Seyfert 1s. However, in 3 NLS1s, ASCA finds common characteristics of these exciting new class of AGN (active galactic nuclei): a very strong high temperature soft excess, weak hard tail, a possible blue shifted ionized oxygen edge, and rapid large amplitude variability characterized by flares and quiescent periods. It is necessary to observe many more such objects in order to understand the physical processes underlying the different phenomenology in ASCA. ASCA observations of two NLS1s discovered by ROSAT's all sky survey were proposed and an observation of one of these objects, RX J0439-45, was awarded. The results of spectral and variability analysis are included in Leighly 1999ab, and preliminary results are found in Leighly 1998ab.

  6. The Brightest Galaxies at Cosmic Dawn: Securing the Largest Samples of z=9-11 galaxies for JWST by leveraging the HST archive with Spitzer/IRAC.

    NASA Astrophysics Data System (ADS)

    Bouwens, Rychard; Trenti, Michele; Calvi, Valentina; Bernard, Stephanie; Labbe, Ivo; Oesch, Pascal; Coe, Dan; Holwerda, Benne; Bradley, Larry; Mason, Charlotte; Schmidt, Kasper; Illingworth, Garth

    2015-10-01

    Hubble's WFC3 has been a game changer for studying early galaxy formation in the first 700 Myr after the Big Bang. Reliable samples of sources up to z~10, which can be discovered only from space, are now constraining the evolution of the galaxy luminosity function into the epoch of reionization. Despite these efforts, the size of the highest redshift galaxy samples (z >9 and especially z > 10) is still very small, particularly at high luminosities (L > L*). To deliver transformational results, much larger numbers of bright z > 9 galaxies are needed both to map out the bright end of the luminosity/mass function and for spectroscopic follow-up (with JWST and otherwise). One especially efficient way of expanding current samples is (1) to leverage the huge amounts of pure-parallel data available with HST to identify large numbers of candidate z ~ 9 - 11 galaxies and (2) to follow up each candidate with shallow Spitzer/IRAC observations to distinguish the bona- fide z ~ 9 - 11 galaxies from z ~ 2 old, dusty galaxies. For this program we are requesting shallow Spitzer/IRAC follow-up of 20 candidate z ~ 9 - 11 galaxies we have identified from 130 WFC3/IR pointings obtained from more than 4 separate HST programs with no existing IRAC coverage. Based on our previous CANDELS/GOODS searches, we expect to confirm 5 to 10 sources as L > L* galaxies at z >= 9. Our results will be used to constrain the bright end of the LF at z >= 9, to provide targets for Keck spectroscopy to constrain the ionization state of the z > 8 universe, and to furnish JWST with bright targets for spectroscopic follow-up studies.

  7. Physical conditions in the x-ray emission-line gas in the Seyfert 2 galaxy NGC 1068

    NASA Astrophysics Data System (ADS)

    Sharma, Neetika

    Active Galactic Nuclei (AGN) reside in the centers of many (10%) galaxies. The nuclear spectra exhibit a broad (from radio to gamma-rays) non-stellar continuum which exceeds the luminosity of the host. AGN are thought to be powered by accretion of matter onto a supermassive black hole (BH~10 6--109 times the mass of the Sun). Since this activity takes place in a relatively small region (<< 3 light years), the central engine of even the closest AGN cannot be imaged directly with current technology. Nevertheless, spectroscopic observations can help us constrain the conditions of the gas very close to the BH. The scientific goal of my thesis is to examine the physical conditions in the circumnuclear regions of the Seyfert 2 galaxy NGC 1068. The soft X-ray spectrum comprises a multitude of emission lines including those of C, N, O, Ne, Mg, that arise in gas that is spatially extended over ~1000 light years. Radiative recombination continuum widths indicate the gas is photoionized and I model it finding a two-zone solution with unusual abundances attributed to the star formation history of the galaxy. Also of interest are the Fe K complex of em.

  8. Optical, near, infrared and ultraviolet monitoring of the Seyfert 1 galaxy Markarian 335

    NASA Technical Reports Server (NTRS)

    Shrader, Chris R.; Sun, W.-H.; Turner, T. J.; Hintzen, P. M.

    1990-01-01

    Preliminary results of a multifrequency monitoring campaign for the bright, Seyfert 1 galactic nuclei Mkn335 are presented. Nearly uniform sampling at 3 day intervals is achieved quasi simultaneously at each wavelength band. Wavelength dependent variability is seen at the 20 to 30 percent level. Interpretation of variability in terms of geometrically thin, optically thick accretion disk models is discussed. The inferred blackhole masses and accretion rates are discussed. Possible correlation between continuum and emission line variations is discussed.

  9. The Spitzer Survey of Stellar Structure in Galaxies (S4G): Stellar Masses, Sizes, and Radial Profiles for 2352 Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Muñoz-Mateos, Juan Carlos; Sheth, Kartik; Regan, Michael; Kim, Taehyun; Laine, Jarkko; Erroz-Ferrer, Santiago; Gil de Paz, Armando; Comeron, Sebastien; Hinz, Joannah; Laurikainen, Eija; Salo, Heikki; Athanassoula, E.; Bosma, Albert; Bouquin, Alexandre Y. K.; Schinnerer, Eva; Ho, Luis; Zaritsky, Dennis; Gadotti, Dimitri A.; Madore, Barry; Holwerda, Benne; Menéndez-Delmestre, Karín; Knapen, Johan H.; Meidt, Sharon; Querejeta, Miguel; Mizusawa, Trisha; Seibert, Mark; Laine, Seppo; Courtois, Helene

    2015-07-01

    The Spitzer Survey of Stellar Structure in Galaxies is a volume, magnitude, and size-limited survey of 2352 nearby galaxies with deep imaging at 3.6 and 4.5 μm. In this paper, we describe our surface photometry pipeline and showcase the associated data products that we have released to the community. We also identify the physical mechanisms leading to different levels of central stellar mass concentration for galaxies with the same total stellar mass. Finally, we derive the local stellar mass-size relation at 3.6 μm for galaxies of different morphologies. Our radial profiles reach stellar mass surface densities below ˜ 1 {M}⊙ {{pc}}-2. Given the negligible impact of dust and the almost constant mass-to-light ratio at these wavelengths, these profiles constitute an accurate inventory of the radial distribution of stellar mass in nearby galaxies. From these profiles we have also derived global properties such as asymptotic magnitudes (and the corresponding stellar masses), isophotal sizes and shapes, and concentration indices. These and other data products from our various pipelines (science-ready mosaics, object masks, 2D image decompositions, and stellar mass maps) can be publicly accessed at IRSA (http://irsa.ipac.caltech.edu/data/SPITZER/S4G/).

  10. Spitzer/Infrared Array Camera near-infrared features in the outer parts of S4G galaxies

    NASA Astrophysics Data System (ADS)

    Laine, Seppo; Knapen, Johan H.; Muñoz-Mateos, Juan-Carlos; Kim, Taehyun; Comerón, Sébastien; Martig, Marie; Holwerda, Benne W.; Athanassoula, E.; Bosma, Albert; Johansson, Peter H.; Erroz-Ferrer, Santiago; Gadotti, Dimitri A.; Gil de Paz, Armando; Hinz, Joannah; Laine, Jarkko; Laurikainen, Eija; Menéndez-Delmestre, Karín; Mizusawa, Trisha; Regan, Michael W.; Salo, Heikki; Sheth, Kartik; Seibert, Mark; Buta, Ronald J.; Cisternas, Mauricio; Elmegreen, Bruce G.; Elmegreen, Debra M.; Ho, Luis C.; Madore, Barry F.; Zaritsky, Dennis

    2014-11-01

    We present a catalogue and images of visually detected features, such as asymmetries, extensions, warps, shells, tidal tails, polar rings, and obvious signs of mergers or interactions, in the faint outer regions (at and outside of R25) of nearby galaxies. This catalogue can be used in future quantitative studies that examine galaxy evolution due to internal and external factors. We are able to reliably detect outer region features down to a brightness level of 0.03 MJy sr-1 pixel-1 at 3.6 μm in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We also tabulate companion galaxies. We find asymmetries in the outer isophotes in 22 ± 1 per cent of the sample. The asymmetry fraction does not correlate with galaxy classification as an interacting galaxy or merger remnant, or with the presence of companions. We also compare the detected features to similar features in galaxies taken from cosmological zoom re-simulations. The simulated images have a higher fraction (33 per cent) of outer disc asymmetries, which may be due to selection effects and an uncertain star formation threshold in the models. The asymmetries may have either an internal (e.g. lopsidedness due to dark halo asymmetry) or external origin.

  11. Quantifying the UV-continuum slopes of galaxies to z ˜ 10 using deep Hubble+Spitzer/IRAC observations

    NASA Astrophysics Data System (ADS)

    Wilkins, Stephen M.; Bouwens, Rychard J.; Oesch, Pascal A.; Labbé, Ivo; Sargent, Mark; Caruana, Joseph; Wardlow, Julie; Clay, Scott

    2016-01-01

    Measurements of the UV-continuum slopes β provide valuable information on the physical properties of galaxies forming in the early universe, probing the dust reddening, age, metal content, and even the escape fraction. While constraints on these slopes generally become more challenging at higher redshifts as the UV-continuum shifts out of the Hubble Space Telescope bands (particularly at z > 7), such a characterization actually becomes abruptly easier for galaxies in the redshift window z = 9.5-10.5 due to the Spitzer/Infrared Array Camera 3.6 μm-band probing the rest-UV continuum and the long wavelength baseline between this Spitzer band and the Hubble Hf160w band. Higher S/N constraints on β are possible at z ˜ 10 than at z = 8. Here, we take advantage of this opportunity and five recently discovered bright z = 9.5-10.5 galaxies to present the first measurements of the mean β for a multi-object sample of galaxy candidates at z ˜ 10. We find the measured βobs's of these candidates are -2.1 ± 0.3 ± 0.2 (random and systematic), only slightly bluer than the measured β's (βobs ≈ -1.7) at 3.5 < z < 7.5 for galaxies of similar luminosities. Small increases in the stellar ages, metallicities, and dust content of the galaxy population from z ˜ 10 to z ˜ 7 could easily explain the apparent evolution in β.

  12. A Cutoff in the X-Ray Fluctuation Power Density Spectrum of the Seyfert 1 Galaxy NGC 3516

    NASA Technical Reports Server (NTRS)

    Edelson, Rick; Nandra, Kirpal

    1999-01-01

    During 1997 March-July, RXTE observed the bright, strongly variable Seyfert 1 galaxy NGC 3516 once every approx. 12.8 hr for 4.5 months and nearly continuously (with interruptions due to SAA passage but not Earth occultation) for a 4.2 day period in the middle. These were followed by ongoing monitoring once every approx. 4.3 days. These data are used to construct the first well-determined X-ray fluctuation power density spectrum (PDS) of an active galaxy to span more than 4 decades of usable temporal frequency. The PDS shows no signs of any strict or quasi-periodicity, but does show a progressive flattening of the power-low slope from -1.74 at short time scales to -0.73 at longer time scales. This is the clearest observation to date of the long-predicted cutoff in the PDS. The characteristic variability time scale corresponding to this cutoff temporal frequency is approx. 1 month. Although it is unclear how this time scale may be interpreted in terms of a physical size or process, there are several promising candidate models. The PDS appears similar to those seen for Galactic black hole candidates such as Cyg X-1, suggesting that these two classes of objects with very different luminosities and putative black hole masses (differing by more than a factor of 10(exp 5)) may have similar X-ray generation processes and structures.

  13. Multi-wavelength observations of the narrow-line Seyfert 1 galaxy RX J2314.9+2243

    NASA Astrophysics Data System (ADS)

    Komossa, S.; Myserlis, I.; Fuhrmann, L.; Xu, D.; Grupe, D.; Fan, Z.; Yao, S.; Angelakis, E.; Karamanavis, V.; Zensus, J. A.; Yuan, W.

    2016-02-01

    Narrow-line Seyfert 1 (NLS1) galaxies are a sub-class of active galactic nuclei (AGN) with relatively low-mass black holes, accreting near the Eddington rate. A small fraction of them is radio-loud and harbors relativistic jets. As a class, these provide us with new insights into the cause(s) of radio-loudness, the blazar phenomenon at low black hole masses, and the operation of radio-mode feedback. The NLS1 galaxy RXJ2314.9+2243 is remarkable for its multi-wavelength properties. We present new radio observations taken at Effelsberg, and a summary of the recent results from our multi-wavelength study. RXJ2314.9+2243 is radio-loud, luminous in the infrared, has a flat X-ray spectrum and peculiar UV spectrum, and hosts an exceptionally broad and blueshifted [OIII]λ5007 emission line, indicating the presence of a strong outflow. RXJ2314.9+2243 likely represents an extreme case of AGN induced feedback in the local universe.

  14. The extreme behavior of the radio-loud narrow-line Seyfert 1 galaxy J0849+5108

    SciTech Connect

    Maune, Jeremy D.; Eggen, Joseph R.; Miller, H. Richard; Marshall, Kevin; Readhead, Anthony C. S.; Hovatta, Talvikki; King, Oliver

    2014-10-10

    Simultaneous radio, optical (both photometry and polarimetry), X-ray, and γ-ray observations of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy J0849+5108 are presented. A massive three-magnitude optical flare across five nights in 2013 April is detected, along with associated flux increases in the γ-ray, infrared, and radio regimes; no comparable event was detected in the X-rays, though this may be due to poor coverage. A spectral energy distribution (SED) for the object using quasi-simultaneous data centered on the optical flare is compared to the previously published SEDs for the object by D'Ammando et al. The flare event coincided with a high degree of optical polarization. High amplitude optical microvariability is clearly detected, and is found to be of comparable amplitude when the object is observed in both faint and bright states. The object is also seen to undergo rapid shifts in polarization in both degree and electric vector position angle within a single night. J0849+5108 appears to show even more extreme variability than that previously reported for the similar object J0948+0022. These observations appear to support the growing claim that some RL-NLSy1 galaxies constitute a sub-class of blazar-like active galactic nuclei.

  15. Reverberation Mapping of a Low-mass Black Hole in a Narrow-line Seyfert 1 Galaxy

    NASA Astrophysics Data System (ADS)

    Rafter, Stephen E.; Kaspi, Shai; Chelouche, Doron; Sabach, Efrat; Karl, David; Behar, Ehud

    2013-08-01

    We present results of a reverberation mapping (RM) campaign on the low black hole mass narrow-line Seyfert 1 (NLS1) galaxy SDSS J113913.91+335551.1 (hereafter SL01). Using the Hβ measurements, we find a time lag \\tau = 12.5^{+0.5}_{-11} days and a broad-line velocity width of 1450 km s-1 which implies a black hole mass of 3.8^{+0.6}_{-2.8} \\times 10^{6} M ⊙. To further bolster our time lag results, we employ a secondary method based on the multivariate correlation function as described in Chelouche & Zucker, in which case we obtain consistent lags for the Balmer lines, yet without the need to spectrally deconvolve line from continuum emission processes. Given SL01's luminosity (L bol ≈ 7 × 1043 erg s-1), we estimate an Eddington ratio (L bol/L Edd) of ~0.18. This fairly low-mass determination and rather high L bol/L Edd is consistent with the current paradigm that the nuclei of NLS1 galaxies host small black holes (as low as 106 M ⊙) with high accretion rates. SL01 is one of only a few NLS1s to date with robust RM results.

  16. REVERBERATION MAPPING OF A LOW-MASS BLACK HOLE IN A NARROW-LINE SEYFERT 1 GALAXY

    SciTech Connect

    Rafter, Stephen E.; Kaspi, Shai; Sabach, Efrat; Karl, David; Behar, Ehud; Chelouche, Doron E-mail: shai@physics.technion.ac.il E-mail: doron@sci.haifa.ac.il

    2013-08-10

    We present results of a reverberation mapping (RM) campaign on the low black hole mass narrow-line Seyfert 1 (NLS1) galaxy SDSS J113913.91+335551.1 (hereafter SL01). Using the H{beta} measurements, we find a time lag {tau}= 12.5{sup +0.5}{sub -11} days and a broad-line velocity width of 1450 km s{sup -1} which implies a black hole mass of 3.8{sup +0.6}{sub -2.8} Multiplication-Sign 10{sup 6} M{sub Sun }. To further bolster our time lag results, we employ a secondary method based on the multivariate correlation function as described in Chelouche and Zucker, in which case we obtain consistent lags for the Balmer lines, yet without the need to spectrally deconvolve line from continuum emission processes. Given SL01's luminosity (L{sub bol} Almost-Equal-To 7 Multiplication-Sign 10{sup 43} erg s{sup -1}), we estimate an Eddington ratio (L{sub bol}/L{sub Edd}) of {approx}0.18. This fairly low-mass determination and rather high L{sub bol}/L{sub Edd} is consistent with the current paradigm that the nuclei of NLS1 galaxies host small black holes (as low as 10{sup 6} M{sub Sun }) with high accretion rates. SL01 is one of only a few NLS1s to date with robust RM results.

  17. Distribution of Molecules in the Circumnuclear Disk and Surrounding Starburst Ring in the Seyfert Galaxy NGC 1068 Observed with ALMA

    NASA Astrophysics Data System (ADS)

    Takano, S.; Nakajima, T.; Kohno, K.; Harada, N.; Herbst, E.; Tamura, Y.; Izumi, T.; Taniguchi, A.; Tosaki, T.

    2015-12-01

    We report distributions of several molecular transitions including shock and dust related species (13CO and C18O J = 1-0, 13CN N = 1-0, CS J = 2-1, SO JN = 32-21, HNCO JKa,Kc = 50,5-40,4, HC3N J = 11-10, 12-11, CH3OH JK = 2K-1K, and CH3CN JK = 6K-5K) in the nearby Seyfert 2 galaxy NGC 1068 observed with ALMA. The central ˜1' (˜4.3 kpc) of this galaxy was observed in the 100 GHz region with an angular resolution of ˜4" x 2" (290 pc x 140 pc) to study the effects of an active galactic nucleus and its surrounding starburst ring on molecular abundances. We report a classification of molecular distributions into three main categories. Organic molecules such as CH3CN are found to be concentrated in the circumnuclear disk. In the starburst ring, the intensity of methanol at each clumpy region is not consistent with that of 13CO.

  18. High-frequency excess in the radio continuum spectrum of the type-1 Seyfert galaxy NGC 985

    NASA Astrophysics Data System (ADS)

    Doi, Akihiro; Inoue, Yoshiyuki

    2016-08-01

    The Seyfert galaxy NGC 985 is known to show a high-frequency excess in its radio continuum spectrum at a milli-Jansky level on the basis of previous observations at 1.4-15 GHz; a steep spectrum at low frequencies (a spectral index, α = -1.10 ± 0.03) changes at ˜10 GHz into an inverted spectrum at higher frequencies (α = +0.86 ± 0.09). We conduct new observations at 15-43 GHz using the Very Large Array and at 100 GHz using the Nobeyama Millimeter Array. As a result, the high-frequency excess has been confirmed as continuing at even higher radio frequencies, up to 43 GHz. The non-detection at 100 GHz was not so strong a constraint, and therefore the spectral behavior above 43 GHz remains unclear. The astrometric position of the high-frequency excess component coincides with the optical position of the Seyfert nucleus and the low-frequency radio position to an accuracy of 0{^''.}1, corresponding to ˜80 pc; the radio source size is constrained to be <0{^''.}02, corresponding to <16 pc. We discuss the physical origin of the observed high-frequency excess component. Dust emission at the Rayleigh-Jeans regime, free-free emission from X-ray radiating high-temperature plasma, free-free emission from the ensemble of broad-line region clouds, or thermal synchrotron from hot accretion flow cannot be responsible for the observed radio flux. Compact jets under synchrotron self-absorption may be unlikely in terms of observed time scales. Alternatively, we cannot rule out the hypotheses of synchrotron jets free-free absorbed by a circumnuclear photo-ionized region, and self-absorbed nonthermal synchrotron from disk corona, as the origin of the high-frequency excess component.

  19. Accretion disc/corona emission from a radio-loud narrow-line Seyfert 1 galaxy PKS 0558-504

    NASA Astrophysics Data System (ADS)

    Ghosh, R.; Dewangan, G. C.; Raychaudhuri, B.

    2016-02-01

    Approximately 10-20 per cent of active galactic nuclei (AGN) are known to eject powerful jets from the innermost regions. There is very little observational evidence if the jets are powered by spinning black holes and if the accretion discs extend to the innermost regions in radio-loud AGN. Here, we study the soft X-ray excess, the hard X-ray spectrum and the optical/UV emission from the radio-loud narrow-line Seyfert 1 galaxy PKS 0558-504 using Suzaku and Swift observations. The broad-band X-ray continuum of PKS 0558-504 consists of a soft X-ray excess emission below 2 keV that is well described by a blackbody (kT ˜ 0.13 keV) and high-energy emission that is well described by a thermal Comptonization (compps) model with kTe ˜ 250 keV, optical depth τ ˜ 0.05 (spherical corona) or kTe ˜ 90 keV, τ ˜ 0.5 (slab corona). The Comptonizing corona in PKS 0558-504 is likely hotter than in radio-quiet Seyferts such as IC 4329A and Swift J2127.4+5654. The observed soft X-ray excess can be modelled as blurred reflection from an ionized accretion disc or optically thick thermal Comptonization in a low-temperature plasma. Both the soft X-ray excess emission when interpreted as the blurred reflection and the optical/UV to soft X-ray emission interpreted as intrinsic disc Comptonized emission implies spinning (a > 0.6) black hole. These results suggest that disc truncation at large radii and retrograde black hole spin both are unlikely to be the necessary conditions for launching the jets.

  20. High-frequency excess in the radio continuum spectrum of the type-1 Seyfert galaxy NGC 985

    NASA Astrophysics Data System (ADS)

    Doi, Akihiro; Inoue, Yoshiyuki

    2016-06-01

    The Seyfert galaxy NGC 985 is known to show a high-frequency excess in its radio continuum spectrum at a milli-Jansky level on the basis of previous observations at 1.4-15 GHz; a steep spectrum at low frequencies (a spectral index, α = -1.10 ± 0.03) changes at ˜10 GHz into an inverted spectrum at higher frequencies (α = +0.86 ± 0.09). We conduct new observations at 15-43 GHz using the Very Large Array and at 100 GHz using the Nobeyama Millimeter Array. As a result, the high-frequency excess has been confirmed as continuing at even higher radio frequencies, up to 43 GHz. The non-detection at 100 GHz was not so strong a constraint, and therefore the spectral behavior above 43 GHz remains unclear. The astrometric position of the high-frequency excess component coincides with the optical position of the Seyfert nucleus and the low-frequency radio position to an accuracy of 0{^''.}1, corresponding to ˜80 pc; the radio source size is constrained to be <0{^''.}02, corresponding to <16 pc. We discuss the physical origin of the observed high-frequency excess component. Dust emission at the Rayleigh-Jeans regime, free-free emission from X-ray radiating high-temperature plasma, free-free emission from the ensemble of broad-line region clouds, or thermal synchrotron from hot accretion flow cannot be responsible for the observed radio flux. Compact jets under synchrotron self-absorption may be unlikely in terms of observed time scales. Alternatively, we cannot rule out the hypotheses of synchrotron jets free-free absorbed by a circumnuclear photo-ionized region, and self-absorbed nonthermal synchrotron from disk corona, as the origin of the high-frequency excess component.

  1. RX J1301.9+2747: A HIGHLY VARIABLE SEYFERT GALAXY WITH EXTREMELY SOFT X-RAY EMISSION

    SciTech Connect

    Sun Luming; Shu Xinwen; Wang Tinggui E-mail: xwshu@mail.ustc.edu.cn

    2013-05-10

    In this paper we present a temporal and spectral analysis of X-ray data from XMM-Newton and Chandra observations of the ultrasoft and variable Seyfert galaxy RX J1301.9+2747. In both observations the source clearly displays two distinct states in the X-ray band: a long quiescent state and a short flare (or eruptive) state which differs in count rates by a factor of 5-7. The transition from the quiescent to the flare state occurs in 1-2 ks. We have observed that the quiescent state spectrum is unprecedentedly steep with a photon index {Gamma} {approx} 7.1, and the spectrum of the flare state is flatter with {Gamma} {approx} 4.4. X-rays above 2 keV were not significantly detected in either state. In the quiescent state, the spectrum appears to be dominated by a blackbody component of temperature about {approx}30-40 eV, which is comparable to the expected maximum effective temperature from the inner accretion disk. The quiescent state, however, requires an additional steep power law, presumably arising from Comptonization by transient heated electrons. The optical spectrum from the Sloan Digital Sky Survey shows Seyfert-like narrow lines for RX J1301.9+2747, while Hubble Space Telescope imaging reveals a central point source for the object. In order to precisely determine the hard X-ray component, future longer X-ray observations are required. This will help constrain the accretion disk model for RX J1301.9+2747, and shed new light on the characteristics of the corona and accretion flows around black holes.

  2. Unification of X-ray Winds in Seyfert Galaxies: From Ultra-fast Outflows to Warm Absorbers

    NASA Astrophysics Data System (ADS)

    Tombesi, Francesco; Cappi, M.; Reeves, J.; Nemmen, R.; Braito, V.; Gaspari, M.; Reynolds, C. S.

    2013-04-01

    The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60%, consistent with previous studies. The fraction of sources with UFOs is >34%, >67% of which also show WAs. The large dynamic range obtained when considering all the absorbers together allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. The absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. This strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The observed parameters and correlations are consistent with both radiation pressure through Compton scattering and MHD processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, have a sufficiently high mechanical power to significantly contribute to the AGN feedback.

  3. Serendipity Observations of Far Infrared Cirrus Emission in the Spitzer Infrared Nearby Galaxies Survey: Analysis of Far-Infrared Correlations

    NASA Astrophysics Data System (ADS)

    Bot, Caroline; Helou, George; Boulanger, François; Lagache, Guilaine; Miville-Deschenes, Marc-Antoine; Draine, Bruce; Martin, Peter

    2009-04-01

    We present an analysis of far-infrared (FIR) dust emission from diffuse cirrus clouds. This study is based on serendipitous observations at 160 μm at high-galactic latitude with the Multiband Imaging Photometer onboard the Spitzer Space Telescope by the Spitzer Infrared Nearby Galaxies Survey. These observations are complemented with IRIS data at 100 and 60 μm and constitute one of the most sensitive and unbiased samples of FIR observations at a small scale of diffuse interstellar clouds. Outside regions dominated by the cosmic infrared background fluctuations, we observe a substantial scatter in the 160/100 colors from cirrus emission. We compared the 160/100 color variations to 60/100 colors in the same fields and find a trend of decreasing 60/100 with increasing 160/100. This trend cannot be accounted for by current dust models by changing solely the interstellar radiation field. It requires a significant change of dust properties such as grain size distribution or emissivity or a mixing of clouds in different physical conditions along the line of sight. These variations are important as a potential confusing foreground for extragalactic studies. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

  4. GRAND DESIGN AND FLOCCULENT SPIRALS IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

    SciTech Connect

    Elmegreen, Debra Meloy; Yau, Andrew; Elmegreen, Bruce G.; Athanassoula, E.; Bosma, Albert; Helou, George; Sheth, Kartik; Ho, Luis C.; Madore, Barry F.; Menendez-Delmestre, KarIn; Gadotti, Dimitri A.; Knapen, Johan H.; Laurikainen, Eija; Salo, Heikki; Meidt, Sharon E.; Regan, Michael W.; Zaritsky, Dennis; Aravena, Manuel

    2011-08-10

    Spiral arm properties of 46 galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S{sup 4}G) were measured at 3.6 {mu}m, where extinction is small and the old stars dominate. The sample includes flocculent, multiple arm, and grand design types with a wide range of Hubble and bar types. We find that most optically flocculent galaxies are also flocculent in the mid-IR because of star formation uncorrelated with stellar density waves, whereas multiple arm and grand design galaxies have underlying stellar waves. Arm-interarm contrasts increase from flocculent to multiple arm to grand design galaxies and with later Hubble types. Structure can be traced further out in the disk than in previous surveys. Some spirals peak at mid-radius while others continuously rise or fall, depending on Hubble and bar type. We find evidence for regular and symmetric modulations of the arm strength in NGC 4321. Bars tend to be long, high amplitude, and flat-profiled in early-type spirals, with arm contrasts that decrease with radius beyond the end of the bar, and they tend to be short, low amplitude, and exponential-profiled in late Hubble types, with arm contrasts that are constant or increase with radius. Longer bars tend to have larger amplitudes and stronger arms.

  5. The Carnegie-Spitzer-IMACS redshift survey of galaxy evolution since z = 1.5. I. Description and methodology

    SciTech Connect

    Kelson, Daniel D.; Williams, Rik J.; Dressler, Alan; McCarthy, Patrick J.; Shectman, Stephen A.; Mulchaey, John S.; Villanueva, Edward V.; Crane, Jeffrey D.; Quadri, Ryan F.

    2014-03-10

    We describe the Carnegie-Spitzer-IMACS (CSI) Survey, a wide-field, near-IR selected spectrophotometric redshift survey with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on Magellan-Baade. By defining a flux-limited sample of galaxies in Spitzer Infrared Array Camera 3.6 μm imaging of SWIRE fields, the CSI Survey efficiently traces the stellar mass of average galaxies to z ∼ 1.5. This first paper provides an overview of the survey selection, observations, processing of the photometry and spectrophotometry. We also describe the processing of the data: new methods of fitting synthetic templates of spectral energy distributions are used to derive redshifts, stellar masses, emission line luminosities, and coarse information on recent star formation. Our unique methodology for analyzing low-dispersion spectra taken with multilayer prisms in IMACS, combined with panchromatic photometry from the ultraviolet to the IR, has yielded high-quality redshifts for 43,347 galaxies in our first 5.3 deg{sup 2} of the SWIRE XMM-LSS field. We use three different approaches to estimate our redshift errors and find robust agreement. Over the full range of 3.6 μm fluxes of our selection, we find typical redshift uncertainties of σ {sub z}/(1 + z) ≲ 0.015. In comparisons with previously published spectroscopic redshifts we find scatters of σ {sub z}/(1 + z) = 0.011 for galaxies at 0.7 ≤ z ≤ 0.9, and σ {sub z}/(1 + z) = 0.014 for galaxies at 0.9 ≤ z ≤ 1.2. For galaxies brighter and fainter than i = 23 mag, we find σ {sub z}/(1 + z) = 0.008 and σ {sub z}/(1 + z) = 0.022, respectively. Notably, our low-dispersion spectroscopy and analysis yields comparable redshift uncertainties and success rates for both red and blue galaxies, largely eliminating color-based systematics that can seriously bias observed dependencies of galaxy evolution on environment.

  6. The Carnegie-Spitzer-IMACS Redshift Survey of Galaxy Evolution since z = 1.5. I. Description and Methodology

    NASA Astrophysics Data System (ADS)

    Kelson, Daniel D.; Williams, Rik J.; Dressler, Alan; McCarthy, Patrick J.; Shectman, Stephen A.; Mulchaey, John S.; Villanueva, Edward V.; Crane, Jeffrey D.; Quadri, Ryan F.

    2014-03-01

    We describe the Carnegie-Spitzer-IMACS (CSI) Survey, a wide-field, near-IR selected spectrophotometric redshift survey with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on Magellan-Baade. By defining a flux-limited sample of galaxies in Spitzer Infrared Array Camera 3.6 μm imaging of SWIRE fields, the CSI Survey efficiently traces the stellar mass of average galaxies to z ~ 1.5. This first paper provides an overview of the survey selection, observations, processing of the photometry and spectrophotometry. We also describe the processing of the data: new methods of fitting synthetic templates of spectral energy distributions are used to derive redshifts, stellar masses, emission line luminosities, and coarse information on recent star formation. Our unique methodology for analyzing low-dispersion spectra taken with multilayer prisms in IMACS, combined with panchromatic photometry from the ultraviolet to the IR, has yielded high-quality redshifts for 43,347 galaxies in our first 5.3 deg2 of the SWIRE XMM-LSS field. We use three different approaches to estimate our redshift errors and find robust agreement. Over the full range of 3.6 μm fluxes of our selection, we find typical redshift uncertainties of σ z /(1 + z) <~ 0.015. In comparisons with previously published spectroscopic redshifts we find scatters of σ z /(1 + z) = 0.011 for galaxies at 0.7 <= z <= 0.9, and σ z /(1 + z) = 0.014 for galaxies at 0.9 <= z <= 1.2. For galaxies brighter and fainter than i = 23 mag, we find σ z /(1 + z) = 0.008 and σ z /(1 + z) = 0.022, respectively. Notably, our low-dispersion spectroscopy and analysis yields comparable redshift uncertainties and success rates for both red and blue galaxies, largely eliminating color-based systematics that can seriously bias observed dependencies of galaxy evolution on environment. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  7. Upholding the unified model for active galactic nuclei: VLT/FORS2 spectropolarimetry of Seyfert 2 galaxies

    NASA Astrophysics Data System (ADS)

    Ramos Almeida, C.; Martínez González, M. J.; Asensio Ramos, A.; Acosta-Pulido, J. A.; Hönig, S. F.; Alonso-Herrero, A.; Tadhunter, C. N.; González-Martín, O.

    2016-09-01

    The origin of the unification model for active galactic nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in ˜30-40 per cent of the nearby Sy2s observed to date. Here we present new VLT/FORS2 optical spectropolarimetry of a sample of 15 Sy2s, including Compton-thin and Compton-thick sources. The sample includes six galaxies without previously published spectropolarimetry, some of them normally treated as non-hidden BLR (NHBLR) objects in the literature, four classified as NHBLR, and five as HBLR based on previous data. We report ≥4σ detections of a HBLR in 11 of these galaxies (73 per cent of the sample) and a tentative detection in NGC 5793, which is Compton-thick according to the analysis of X-ray data performed here. Our results confirm that at least some NHBLRs are misclassified, bringing previous publications reporting differences between HBLR and NHBLR objects into question. We detect broad Hα and Hβ components in polarized light for 10 targets, and just broad Hα for NGC 5793 and NGC 6300, with line widths ranging between 2100 and 9600 km s-1. High bolometric luminosities and low column densities are associated with higher polarization degrees, but not necessarily with the detection of the scattered broad components.

  8. FUSE Detection of Galactic and Intrinsic Absorption in the Spectrum of the Seyfert 1 Galaxy 2MASX J21362313-6224008

    NASA Technical Reports Server (NTRS)

    Bonamente, Massimiliano; VanDykeDixon, W.

    2003-01-01

    We present the far-ultraviolet spectrum of the Seyfert 1 galaxy 2MASX 521362313-6224008 obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). The spectrum features absorption from Galactic O VI at two velocities and redshifted H I Lyman beta and gamma, C II, C III, and O VI. The redshifted absorption features represent a single kinematic component blueshifted by approx. 310 km/s relative to the AGN. We use photoionization models to derive the physical parameters of the absorbing gas. An alternative interpretation for the absorption lines is also proposed, whereby the absorbing gas is associated with an intervening galaxy cluster.

  9. FUSE Observations of Galactic and Intrinsic Absorption in the Spectrum of the Seyfert 1 Galaxy 2MASX J21362313-6224008

    NASA Technical Reports Server (NTRS)

    Bonamente, Massimiliano; Dixon, W. Van Dyke

    2004-01-01

    We present the far-ultraviolet spectrum of the Seyfert 1 galaxy 2MASX J21362313-6224008 obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). The spectrum features absorption from Galactic O VI at two velocities and redshifted H I Ly beta and gamma, C II, CIII, and O VI. The redshifted absorption features represent a single kinematic component blueshifted by approx. 310 km/s relative to the active galactic nucleus. We use photoionization models to derive constraints on the physical parameters of the absorbing gas. An alternative interpretation for the absorption lines is also proposed, wherein the absorbing gas is associated with an intervening galaxy cluster.

  10. CANDIDATE CLUSTERS OF GALAXIES AT z > 1.3 IDENTIFIED IN THE SPITZER SOUTH POLE TELESCOPE DEEP FIELD SURVEY

    SciTech Connect

    Rettura, A.; Stern, D.; Martinez-Manso, J.; Gettings, D.; Gonzalez, A. H.; Mei, S.; Ashby, M. L. N.; Brodwin, M.; Stanford, S. A.; Bartlett, J. G.

    2014-12-20

    We present 279 galaxy cluster candidates at z > 1.3 selected from the 94 deg{sup 2} Spitzer South Pole Telescope Deep Field (SSDF) survey. We use a simple algorithm to select candidate high-redshift clusters of galaxies based on Spitzer/IRAC mid-infrared data combined with shallow all-sky optical data. We identify distant cluster candidates adopting an overdensity threshold that results in a high purity (80%) cluster sample based on tests in the Spitzer Deep, Wide-Field Survey of the Boötes field. Our simple algorithm detects all three 1.4 < z ≤ 1.75 X-ray detected clusters in the Boötes field. The uniqueness of the SSDF survey resides not just in its area, one of the largest contiguous extragalactic fields observed with Spitzer, but also in its deep, multi-wavelength coverage by the South Pole Telescope (SPT), Herschel/SPIRE, and XMM-Newton. This rich data set will allow direct or stacked measurements of Sunyaev-Zel'dovich effect decrements or X-ray masses for many of the SSDF clusters presented here, and enable a systematic study of the most distant clusters on an unprecedented scale. We measure the angular correlation function of our sample and find that these candidates show strong clustering. Employing the COSMOS/UltraVista photometric catalog in order to infer the redshift distribution of our cluster selection, we find that these clusters have a comoving number density n{sub c}=(0.7{sub −0.6}{sup +6.3})×10{sup −7} h{sup 3} Mpc{sup −3} and a spatial clustering correlation scale length r {sub 0} = (32 ± 7) h {sup –1} Mpc. Assuming our sample is comprised of dark matter halos above a characteristic minimum mass, M {sub min}, we derive that at z = 1.5 these clusters reside in halos larger than M{sub min}=1.5{sub −0.7}{sup +0.9}×10{sup 14} h{sup −1} M{sub ⊙}. We find that the mean mass of our cluster sample is equal to M{sub mean}=1.9{sub −0.8}{sup +1.0}×10{sup 14} h{sup −1} M{sub ⊙}; thus, our sample contains the progenitors of

  11. Candidate Clusters of Galaxies at z > 1.3 Identified in the Spitzer South Pole Telescope Deep Field Survey

    NASA Astrophysics Data System (ADS)

    Rettura, A.; Martinez-Manso, J.; Stern, D.; Mei, S.; Ashby, M. L. N.; Brodwin, M.; Gettings, D.; Gonzalez, A. H.; Stanford, S. A.; Bartlett, J. G.

    2014-12-01

    We present 279 galaxy cluster candidates at z > 1.3 selected from the 94 deg2 Spitzer South Pole Telescope Deep Field (SSDF) survey. We use a simple algorithm to select candidate high-redshift clusters of galaxies based on Spitzer/IRAC mid-infrared data combined with shallow all-sky optical data. We identify distant cluster candidates adopting an overdensity threshold that results in a high purity (80%) cluster sample based on tests in the Spitzer Deep, Wide-Field Survey of the Boötes field. Our simple algorithm detects all three 1.4 < z <= 1.75 X-ray detected clusters in the Boötes field. The uniqueness of the SSDF survey resides not just in its area, one of the largest contiguous extragalactic fields observed with Spitzer, but also in its deep, multi-wavelength coverage by the South Pole Telescope (SPT), Herschel/SPIRE, and XMM-Newton. This rich data set will allow direct or stacked measurements of Sunyaev-Zel'dovich effect decrements or X-ray masses for many of the SSDF clusters presented here, and enable a systematic study of the most distant clusters on an unprecedented scale. We measure the angular correlation function of our sample and find that these candidates show strong clustering. Employing the COSMOS/UltraVista photometric catalog in order to infer the redshift distribution of our cluster selection, we find that these clusters have a comoving number density nc = (0.7+6.3-0.6) × 10-7 h3 {Mpc}-3 and a spatial clustering correlation scale length r 0 = (32 ± 7) h -1 Mpc. Assuming our sample is comprised of dark matter halos above a characteristic minimum mass, M min, we derive that at z = 1.5 these clusters reside in halos larger than Mmin = 1.5+0.9-0.7 × 1014 h-1 M⊙ . We find that the mean mass of our cluster sample is equal to Mmean = 1.9+1.0-0.8 × 1014 h-1 M⊙ ; thus, our sample contains the progenitors of present-day massive galaxy clusters.

  12. Unification of X-ray Winds in Seyfert Galaxies: From Ultra-fast Outflows to Warm Absorbers

    NASA Technical Reports Server (NTRS)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Nemmen, R. S.; Braito, V.; Gaspari, M.; Reynolds, C. S.

    2013-01-01

    The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60 per cent, consistent with previous studies. The fraction of sources with UFOs is >34 per cent, >67 per cent of which also show WAs. The large dynamic range obtained when considering all the absorbers together, spanning several orders of magnitude in ionization, column, velocity and distance allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. In all the cases, the absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. These evidence strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The UFOs are likely launched from the inner accretion disc and the WAs at larger distances, such as the outer disc and/or torus. We argue that the observed parameters and correlations are, to date, consistent with both radiation pressure through Compton scattering and magnetohydrodynamic processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, show

  13. Unification of X-ray winds in Seyfert galaxies: from ultra-fast outflows to warm absorbers

    NASA Astrophysics Data System (ADS)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Nemmen, R. S.; Braito, V.; Gaspari, M.; Reynolds, C. S.

    2013-04-01

    The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60 per cent, consistent with previous studies. The fraction of sources with UFOs is >34 per cent, >67 per cent of which also show WAs. The large dynamic range obtained when considering all the absorbers together, spanning several orders of magnitude in ionization, column, velocity and distance allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. In all the cases, the absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. These evidence strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The UFOs are likely launched from the inner accretion disc and the WAs at larger distances, such as the outer disc and/or torus. We argue that the observed parameters and correlations are, to date, consistent with both radiation pressure through Compton scattering and magnetohydrodynamic processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, show

  14. Molecular tori in Seyfert galaxies - Feeding the monster and hiding it

    NASA Astrophysics Data System (ADS)

    Krolik, Julian H.; Begelman, Mitchell C.

    1988-06-01

    Much evidence exists that the majority of Seyfert nuclei are surrounded by a geometrically and optically thick torus of dusty, obscuring gas a few parsecs from the center. The authors discuss the principal properties of the gas in the torus. It is almost certainly not smoothly distributed; most of its mass is gathered into clouds. The balance between cloud merger and tidal shearing ensures that the covering factor of these clouds in the axial direction is of order unity and determines the shape of the cloud-size distribution function. It is shown that the same viscous heating responsible for the large geometrical thickness of the obscuring region removes the angular momentum from enough clouds to permit them to be captured by the central black hole, fueling its activity and stabilizing the balance between evaporation and dissipative inflow.

  15. The impact of Spitzer infrared data on stellar mass estimates - and a revised galaxy stellar mass function at 0 < z < 5

    NASA Astrophysics Data System (ADS)

    Elsner, F.; Feulner, G.; Hopp, U.

    2008-01-01

    Aims:We estimate stellar masses of galaxies in the high redshift universe with the intention of determining the influence of newly available Spitzer/IRAC infrared data on the analysis. Based on the results, we probe the mass assembly history of the universe. Methods: We use the GOODS-MUSIC catalog, which provides multiband photometry from the U-filter to the 8 μm Spitzer band for almost 15 000 galaxies with either spectroscopic (for ≈7% of the sample) or photometric redshifts, and apply a standard model fitting technique to estimate stellar masses. We than repeat our calculations with fixed photometric redshifts excluding Spitzer photometry and directly compare the outcomes to look for systematic deviations. Finally we use our results to compute stellar mass functions and mass densities up to redshift z = 5. Results: We find that stellar masses tend to be overestimated on average if further constraining Spitzer data are not included into the analysis. Whilst this trend is small up to intermediate redshifts z ⪉ 2.5 and falls within the typical error in mass, the deviation increases strongly for higher redshifts and reaches a maximum of a factor of three at redshift z ≈ 3.5. Thus, up to intermediate redshifts, results for stellar mass density are in good agreement with values taken from literature calculated without additional Spitzer photometry. At higher redshifts, however, we find a systematic trend towards lower mass densities if Spitzer/IRAC data are included.

  16. MID-INFRARED PROPERTIES OF OH MEGAMASER HOST GALAXIES. I. SPITZER IRS LOW- AND HIGH-RESOLUTION SPECTROSCOPY

    SciTech Connect

    Willett, Kyle W.; Darling, Jeremy; Spoon, Henrik W. W.; Charmandaris, Vassilis; Armus, Lee

    2011-03-15

    We present mid-infrared spectra and photometry from the Infrared Spectrograph on the Spitzer Space Telescope for 51 OH megamasers (OHMs), along with 15 galaxies confirmed to have no megamaser emission above L {sub OH} = 10{sup 2.3} L {sub sun}. The majority of galaxies display moderate-to-deep 9.7 {mu}m amorphous silicate absorption, with OHM galaxies showing stronger average absorption and steeper 20-30 {mu}m continuum emission than non-masing galaxies. Emission from multiple polycyclic aromatic hydrocarbons (PAHs), especially at 6.2, 7.7, and 11.3 {mu}m, is detected in almost all systems. Fine-structure atomic emission (including [Ne II], [Ne III], [S III], and [S IV]) and multiple H{sub 2} rotational transitions are observed in more than 90% of the sample. A subset of galaxies show emission from rarer atomic lines, such as [Ne V], [O IV], and [Fe II]. Fifty percent of the OHMs show absorption from water ice and hydrogenated amorphous carbon grains, while absorption features from CO{sub 2}, HCN, C{sub 2}H{sub 2}, and crystalline silicates are also seen in several OHMs. Column densities of OH derived from 34.6 {mu}m OH absorption are similar to those derived from 1667 MHz OH absorption in non-masing galaxies, indicating that the abundance of masing molecules is similar for both samples. This data paper presents full mid-infrared spectra for each galaxy, along with measurements of line fluxes and equivalent widths, absorption feature depths, and spectral indices.

  17. Probing the physics of Seyfert galaxies using their emission-line regions

    SciTech Connect

    Shastri, P. Kharb, P.; Jose, J.; Ramya, S.; Bhatt, H. C.; Gupta, M.; Dopita, M.; Kewley, L.; Davies, R.; Sutherland, R.; Hampton, E.; Scharwächter, J.; Banfield, J.; Srivastava, S.; Jin, J.; Basurah, H.; Fischer, S.; Panda, S.; Sundar, M. N.; Radhakrishnan, V.

    2015-12-31

    Active galaxies have powerhouses of radiation in their nuclear regions that are driven by accreting super-massive black holes. The accretion system also generates outflows of ionized gas and synchrotron-emitting bipolar jets of plasma, which could have a significant impact on the host galaxy. We have initiated an investigation into the physics of nearby active galaxies by studying the morphology, kinematics, excitation abundance structure, and radio structure of about 120 nearby targets. We present a few early results from this investigation.

  18. The discovery of an O VII emission line in the ASCA spectrum of the Seyfert galaxy NGC 3783

    NASA Technical Reports Server (NTRS)

    George, I. M.; Turner, T. J.; Netzer, H.

    1995-01-01

    We report the first observation of an O VII 0.57 keV emission line in a Seyfert 1 galaxy. NGC 3783 was observed by ASCA twice over a period of 4 days in 1993 December. The source exhibited a approximately 30% change in intensity between the two observations, with most of the variability taking place as a result of steepening of the continuum less than or approximately equal to 1 keV. Spectra from both observations show intense absorption features in the 0.5-1.5 keV band, which can be well fitted by an ionized absorber model of solar composition, column density of 10(exp 22.2)/sq cm and ionization parameter of approximately 7-8; the strongest absorption features being due to O VII and O VIII. Two emission features are also seen in the spectra which we identify as O VII 0.57 keV (equivalent width approximately equals 36 eV) and O VIII 0.65 keV (equivalent width approximately equals 11 eV). We also show that the 3-6 keV continuum of the source is well fitted by a Gamma = 1.3-1.4 power-law continuum, a narrow neutral iron K-shell fluorescence line and a strong iron K-shell absorption edge, possibly corresponding to highly ionized iron.

  19. Monitoring the Violent Activity from the Inner Accretion Disk of the Seyfert 1.9 Galaxy NGC 2992 with RXTE

    NASA Technical Reports Server (NTRS)

    Mruphy, Kendrah D.; Yaqoob, Tahir; Terashima, Yuichi

    2007-01-01

    We present the results of a one year monitoring campaign of the Seyfert 1.9 galaxy NGC 2992 with RXTE. Historically, the source has been shown to vary dramatically in 2-10 keV flux over timescales of years and was thought to be slowly transitioning between periods of quiescence and active accretion. Our results show that in one year the source continuum flux covered almost the entire historical range, making it unlikely that the low-luminosity states correspond to the accretion mechanism switching off. During flaring episodes we found that a highly redshifted Fe K line appears, implying that the violent activity is occurring in the inner accretion disk, within 100 gravitational radii of the central black hole. We also found that the Compton y parameter for the X-ray continuum remained approximately constant during the large amplitude variability. These observations make NGC 2992 well-suited for future multi-waveband monitoring, as a test-bed for constraining accretion models.

  20. X-ray Variability of the Magnetic Cataclysmic Variable V1432 Aql and the Seyfert Galaxy NGC 6814

    NASA Technical Reports Server (NTRS)

    Mukai, K.; Hellier, C.; Madejski, G.; Patterson, J.; Skillman, D. R.

    2003-01-01

    V1432 Aquilae (=RX J1940.2-1025) is the X-ray bright, eclipsing magnetic cataclysmic variable approximately 37 (sup) away from the Seyfert galaxy, NGC 6814. Due to a 0.3% difference between the orbital (12116.3 s) and the spin (12150 s) periods: the accretion geometry changes over the approximately 50 day beat period. Here we report the results of an RXTE campaign to observe the eclipse 25 times, as well as of archival observations with ASCA and BeppoSAX. Having confirmed that the eclipse is indeed caused by the secondary, we use the eclipse timings and profiles to map the accretion geometry as a function of the beat phase. We find that the accretion region is compact, and that it moves relative to the center of white dwarf on the beat period. The amplitude of this movement suggest a low-mass white dwarf, in contrast to the high mass previously estimated from its X-ray spectrum. The size of the X-ray emission region appears to be larger than in other eclipsing magnetic CVs. We also report on the RXTE data as well as the long-term behavior of NGC 6814, indicating flux variability by a factor of at least 10 on time scales of years.

  1. X-ray selected quasars and Seyfert galaxies - Cosmological evolution, luminosity function, and contribution to the X-ray background

    NASA Technical Reports Server (NTRS)

    Maccacaro, T.; Gioia, I. M.; Stocke, J. T.

    1984-01-01

    The cosmological evolution and the X-ray luminosity function of quasars and Seyfert galaxies (active galactic nuclei /AGNs/) are derived and discussed. The sample used consists of 56 objects extracted from the expanded Einstein Observatory Medium Sensitivity Survey, and it is exclusively defined by its X-ray properties. The distribution in space of X-ray selected AGNs is confirmed to be strongly nonuniform; the amount of cosmological evolution required by the data is in agreement with a previous determination based on a smaller sample of objects. The X-ray luminosity function (XLF) is derived. The high-luminosity part of the XLF is satisfactorily described by a power law of slope gamma approximately 3.6. A significant flattening is observed at low luminosities. The simultaneous determination of the cosmological evolution and of the X-ray luminosity function of AGNs is then used to estimate the contribution to the extragalactic diffuse X-ray background. Using the best fit values for the evolution of AGNs and for their volume density, it is found that they contribute approximately 80 percent of the 2 keV diffuse X-ray background. Uncertainties in this estimate are still rather large; however, it seems difficult to reconcile the data with a contribution much less than 50 percent.

  2. Resolving the Large Scale Spectral Variability of the Luminous Seyfert 1 Galaxy 1H 0419-577

    NASA Technical Reports Server (NTRS)

    Pounds, K. A.; Reeves, J. N.; Page, K. L.; OBrien, P. T.

    2004-01-01

    An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in September 2002, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below approximately 1 keV. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was X-ray bright indicated the dominant spectral variability was due to a steep power law or cool Comptonized thermal emission. Four further XMM-Newton observations, with 1H 0419-577 in intermediate flux states, now support that conclusion, while we also find the variable emission component in intermediate state difference spectra to be strongly modified by absorption in low ionisation matter. The variable soft excess is seen to be an artefact of absorption of the underlying continuum while the core soft emission is attributed to recombination in an extended region of more highly ionised gas. This new analysis underlines the importance of fully accounting for absorption in characterizing AGN X-ray spectra.

  3. Exceptional behaviour of X-ray emitting corona in a Seyfert 1 galaxy 1H 0419 - 577

    NASA Astrophysics Data System (ADS)

    Pal, Main; Dewangan, Gulab Chand

    2016-07-01

    We report on six XMM-Newton observations of a Seyfert 1 galaxy 1H 0419-577 during spectacular behaviour of the corona about on 2-3 months time scale. The source reflects similar trend in each energy band from Optical/UV to X-rays during 2002-2003. The Optical/UV emission varies from trough to peak by 4.2-22.1% and peak to trough by 6.6-10.3%. At the same time, the 2 - 10keV powerlaw emission is strongly correlated with soft X-ray excess with similar fractional variability amplitude ˜ 40% suggesting variation in coronal geometry. We also found that the height of X-ray source remains almost similar about 2rg (gravitaional radius) for each observation. This indicates clearly that source size is changing dramatically. Further, the powerlaw emission and Optical/UV emission seem correlated to each other. The observed variation in Optical/UV emission further support the variable size of corona. During incraesing trend of Optical/UV to X-rays, the X-ray source expands horizontally and while decreasing the X-ray source seems to shrink. This is supported by the observed more variation in Optical emission compared to UV emission while decreasing in flux from peak to trough.

  4. A radio detection survey of narrow-line Seyfert 1 galaxies using very long baseline interferometry at 22 GHz

    NASA Astrophysics Data System (ADS)

    Doi, Akihiro; Oyama, Tomoaki; Kono, Yusuke; Yamauchi, Aya; Suzuki, Syunsaku; Matsumoto, Naoko; Tazaki, Fumie

    2016-05-01

    We conducted a high-sensitivity radio detection survey for 40 narrow-line Seyfert 1 (NLS1) galaxies using a very long baseline interferometry (VLBI) technique at 22 GHz through phase-referencing long-time integration and using a newly developing recorder with a data rate of 8 Gbps, which is a candidate of the next generation VLBI data recording systems of the Japanese VLBI Network. The baseline sensitivity was typically a few mJy. The observations resulted in a detection rate of 12/40 for our radio-selected NLS1 sample: 11 out of the 12 detected NLS1s showed inverted radio spectra between 1.4 and 22 GHz on the basis of the Very Large Array flux densities and the VLBI detections. These high fractions suggest that a compact radio core with a high brightness temperature is frequently associated with NLS1 nuclei. On the other hand, at least half of the sample indicated apparently steep spectra even with the limited VLBI sensitivity. Both the inverted and the steep spectrum radio sources are included in the NLS1 population.

  5. Warm Absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Laha, S.; Guainazzi, M.; Dewangan, G.; Chakravorty, S.; Kembhavi, A.

    2014-07-01

    We present results from a homogeneous analysis of the broadband 0.3-10 keV CCD resolution as well as of soft X-ray high-resolution grating spectra of a hard X-ray flux-limited sample of 26 Seyfert galaxies observed with XMM-Newton. We could put a strict lower limit on the detection fraction of 50%. We find a gap in the distribution of the ionisation parameter in the range 0.5

  6. A study of the structure and kinematics of the narrow-line region in Seyfert galaxies. III. Individual objects

    SciTech Connect

    Veilleux, S. )

    1991-03-01

    An individual analysis is presented of the narrow-line profiles of 16 Seyfert galaxies. Substructure is observed in all but one of the sample objects. A direct relationship between the radio structure and these emission-line components is proposed in about half of the objects. The emission-line components generally have flux ratios which are quite similar to the rest of the narrow-line gas. These results suggest that the radio-emitting plasma strongly affects the kinematics of the thermal gas of the narrow-line region (NLR), but not its ionization state. Evidence for ionization/density stratification of the gas in the NLR is found in 4(ionization)/5(density) of the 11 objects for which a multispecies analysis is possible. The stronger cases of stratification are found in the objects whose emission lines present a minimum of profile substructure. A multicomponent model of the NLR is proposed to explain the results of this paper and previous ones. 192 refs.

  7. Extended soft X-ray emission in Seyfert galaxies: ROSAT HRI observations of NGC 3516, NGC 4151, and Markarian 3

    NASA Technical Reports Server (NTRS)

    Morse, Jon A.; Wilson, Andrew S.; Elvis, Martin; Weaver, Kimberly A.

    1995-01-01

    We have used the ROSAT High Resolution Imager (HRI) to examine the distribution of soft X-rays in three nearby Seyfert galaxies with approximately 4 to 5 arcsecs FWHM spatial resolution. A feature of our analysis is an attempt to remove errors in the aspect solution using a method developed by one of us (J.M.). NGC 4151 shows resolved X-ray emission that is spatially correlated with the optical extended narrow-line region (ENLR), confirming the results obtained with the Einstein HRI by Elvis, Briel, & Henry. NGC 3516 is elongated along a position angle of approximately 40 to 220 deg, similar to the direction of the Z-shaped narrow-line region. MRK 3 is very faint in our HRI image and is probably spatially unresolved. We detect the faint X-ray source approximately 2 arcmins west of the MRK 3 nucleus previously found by Turner, Urry, & Mushotzky. We also detected the BL Lac object BL 1207 + 39 approximately 5 arcmins north-northwest of NGC 4151. This object appears spatially unresolved, but some excess X-ray emission may be observed in the azimuthally averaged radial brightness profile of BL 1207 + 39 between radii of 10 arcsecs and 30 arcsecs when compared to a calibration source. A much deeper image is necessary to confirm this result.

  8. THE BLACK HOLE SPIN AND SOFT X-RAY EXCESS OF THE LUMINOUS SEYFERT GALAXY FAIRALL 9

    SciTech Connect

    Lohfink, Anne M.; Reynolds, Christopher S.; Mushotzky, Richard F.; Miller, Jon M.; Brenneman, Laura W.; Nowak, Michael A.; Fabian, Andrew C.

    2012-10-10

    We present an analysis of all XMM-Newton and Suzaku X-ray spectra of the nearby luminous Seyfert galaxy Fairall 9. Confirming previous analyses, we find robust evidence for a broad iron line associated with X-ray reflection from the innermost accretion disk. By fitting a spectral model that includes a relativistically ionized reflection component, we examine the constraints on the inclination of the inner accretion disk and the black hole spin, and the complications introduced by the presence of a photoionized emission line system. Employing multi-epoch fitting, we attempt to obtain robust and concordant measures of the accretion disk parameters. We also clearly see a soft X-ray excess in Fairall 9. During certain epochs, the soft excess can be described with the same disk reflection component that produces the iron line. However, there are epochs where an additional soft component is required. This can be attributed to either an additional highly ionized, strongly blurred disk reflection component or a new X-ray continuum component.

  9. Detection of faint BLR components in the starburst/Seyfert galaxy NGC 6221 and measure of the central BH mass

    NASA Astrophysics Data System (ADS)

    La Franca, Fabio; Onori, Francesca; Ricci, Federica; Bianchi, Stefano; Marconi, Alessandro; Sani, Eleonora; Vignali, Cristian

    2016-04-01

    In the last decade, using single epoch virial based techniques in the optical band, it has been possible to measure the central black hole mass on large type 1 Active Galactive Nuclei (AGN) samples. However these measurements use the width of the broad line region as a proxy of the virial velocities and are therefore difficult to be carried out on those obscured (type 2) or low luminosity AGN where the nuclear component does not dominate in the optical. Here we present the optical and near infrared spectrum of the starburst/Seyfert galaxy NGC 6221, observed with X-shooter/VLT. Previous observations of NGC 6221 in the X-ray band shows an absorbed (N_H=8.5 +/- 0.4 x 10^21 cm^-2) spectrum typical of a type 2 AGN with luminosity log(L_14-195/ erg s^-1) = 42.05, while in the optical band its spectrum is typical of a reddened (A_V=3) starburst. Our deep X-shooter/VLT observations have allowed us to detect faint broad emission in the H_alpha, HeI and Pa_beta lines (FWHM=1400-2300 km s^-1) confirming previous studies indicating that NGC 6221 is a reddened starbust galaxy which hosts an AGN. We use the measure of the broad components to provide a first estimate of its central black hole mass (M_BH = 10^6.6+/-0.3 Msol, lambda_Edd=0.01-0.03), obtained using recently calibrated virial relations suitable for moderately obscured (N_H<10^24 cm^-2) AGN.

  10. Reverberation Mapping of the Gamma-Ray Loud Narrow-line Seyfert 1 Galaxy 1H 0323+342

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Du, Pu; Hu, Chen; Bai, Jin-Ming; Wang, Chuan-Jun; Yi, Wei-Min; Wang, Jian-Guo; Zhang, Ju-Jia; Xin, Yu-Xin; Lun, Bao-Li; Chang, Liang; Fan, Yu-Feng

    2016-06-01

    Recently, 1H 0323+342 has attracted a lot of attention as one of several narrow-line Seyfert 1 galaxies detected in the γ-ray band. To understand their central energy engines and jet phenomena, the black hole mass is important. We made use of the Lijiang 2.4 m Telescope to monitor 1H 0323+342 for more than two months. This galaxy is one of the candidates for a monitoring project of super-Eddington accreting massive black holes. The reverberation mapping shows that Hβ emission has a delayed response of {14.8}-2.7+3.9 days with respect to the SDSS g‧ light curve in the rest frame. The optical Fe ii variations were detected after subtracting host contaminations, and a reverberation with a delay of {15.2}-4.1+7.4 days was found in the rest frame. By assuming the viral factor f BLR = 6.17 for the broad-line region (BLR) velocity characterized by FWHM because of the face-on orientation, we find that the black hole mass derived from Hβ is {M}\\bullet ={3.4}-0.6+0.9× {10}7{M}ȯ , and the accretion rate is \\dot{{M}}={1.11}-0.47+0.69, where \\dot{{M}}={\\dot{M}}\\bullet {c}2/{L}{{Edd}}, {\\dot{M}}\\bullet is the mass accretion rate, L Edd is the Eddington luminosity, and c is the speed of light. This black hole is one order less massive than that given by the Magorrian relation from the bulge mass. We test the relation between accretion rates and radio-loudnesses in all mapped radio-loud active galactic nuclei, and find that 1H 0323+342 falls within this group.

  11. Broadband Observations of the Gamma-Ray Emitting Narrow Line Seyfert 1 Galaxy SBS 0846+513

    NASA Astrophysics Data System (ADS)

    Paliya, Vaidehi S.; Rajput, Bhoomika; Stalin, C. S.; Pandey, S. B.

    2016-03-01

    We present the results of our broadband study of the γ-ray emitting narrow line Seyfert 1 (NLSy1) galaxy SBS 0846+513 (z = 0.585). This includes multiband flux variations, γ-ray spectral analysis, broadband spectral energy distribution (SED) modeling, and intranight optical variability (INOV) observations carried out over six nights between 2012 November and 2013 March using the 2 m Himalayan Chandra Telescope and the 1.3 m telescope at Devasthal, India. Multiple episodes of flaring activity are seen in the γ-ray light curve of the source which are also reflected in the observations at lower frequencies. A statistically significant curvature is noticed in the seven years averaged γ-ray spectrum, thus indicating its similarity with powerful flat spectrum radio quasars (FSRQs). Modeling the SEDs with a one-zone leptonic emission model hints that the optical UV spectrum is dominated by synchrotron radiation, whereas inverse Compton scattering of broad line region photons reproduces the γ-ray part of the SEDs. The source was found to be variable on all the six nights of optical observations with a variation of ∼0.3 mag within a single night, coinciding with a high γ-ray activity state. The observed large amplitude INOV clearly indicates the presence of a closely aligned beamed relativistic jet in SBS 0846+513. Our broadband study supports the recent claims in literature that γ-ray emitting NLSy1 galaxies are similar to blazars and constitute the low black hole mass counterparts to FSRQs.

  12. The Discovery and Characterization of Surprisingly Luminous Galaxy Candidates at 9-10: The Power of Combining HST and Spitzer

    NASA Astrophysics Data System (ADS)

    Illingworth, Garth D.; Oesch, P.; Bouwens, R.; Labbe, I.; XDF/HUDF09 Team

    2014-01-01

    Deep observations with the WFC3/IR camera on HST have pushed the frontier for galaxies in the young universe to 9-11, just ~450 Myr from the Big Bang at the heart of the reionization epoch. However, until recently only a small number of intrinsically very faint galaxies had been identified at these redshifts from extremely deep WFC3/IR data in the XDF/HUDF and the GOODS-South field and from the CLASH cluster survey. This changed with our recent analysis of the completed CANDELS survey data over the GOODS-North/HDF-N field. We discovered four surprisingly bright Lyman-break galaxy candidates at 9-10, the brightest of which has a most probable redshift of 10.2. These sources are a factor ~10-20x more luminous than any previous candidate at redshifts 9-10. The high number of such luminous sources suggests that star-formation was highly stochastic in the very early universe resulting in large field-to-field variance. Furthermore, three of these bright candidates show significant detections in Spitzer/IRAC, substantially enhancing the probability that these galaxies are at 9-10. The IRAC data probes the rest-frame optical light and indicates that these sources already had a stellar mass of 10^9 Msol at a cosmic time of only 450-500 Myr. While the overall star formation rate density of galaxies with SFR>0.7 Msol/yr has been shown to increase rapidly in just 200 Myr from 10 to 8, the discovery of these luminous sources has very promising implications for the detection of galaxies at times significantly earlier than 450 Myr with JWST.

  13. Soft X-ray spectral observations of quasars and high X-ray luminosity Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Petre, R.; Mushotzky, R. F.; Krolik, J. H.; Holt, S. S.

    1983-01-01

    Results of the analysis of 28 Einstein SSS observations of 15 high X-ray luminosity (L(x) 10 to the 435 power erg/s) quasars and Seyfert type 1 nuclei are presented. The 0.75-4.5 keV spectra are in general well fit by a simple model consisting of a power law plus absorption by cold gas. The averager spectral index alpha is 0.66 + or - .36, consistent with alpha for the spectrum of these objects above 2 keV. In all but one case, no evidence was found for intrinsic absorption, with an upper limit of 2 x 10 to the 21st power/sq cm. Neither was evidence found for partial covering of the active nucleus by dense, cold matter (N(H) 10 to the 22nd power/sq cm; the average upper limit on the partial covering fraction is 0.5. There is no obvious correlation between spectral index and 0175-4.5 keV X-ray luminosity (which ranges from 3 x 10 to the 43rd to 47th powers erg/s or with other source properties. The lack of intrinsic X-ray absorption allows us to place constraints on the density and temperature of the broad-line emission region, and narrow line emission region, and the intergalactic medium.

  14. High-Resolution X-Ray Spectroscopy of the Seyfert 2 Galaxy Circinus with Chandra

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita M.; Netzer, Hagai; Kaspi, Shai; Brandt, W. N.; Chartas, G.; Garmire, G. P.; Nousek, John A.; Weaver, K. A.

    2000-01-01

    Results from a 60 ks Chandra High Energy Transmission Grating Spectrometer (HETGS) observation of the nearby Seyfert 2 Circinus are presented. The spectrum shows a wealth of emission lines at both soft and hard X-rays, including lines of Ne, Mg, Si, S, Ar, Ca, and Fe, and a prominent Fe K(alpha) line at 6.4 keV. We identify several of the He-like components and measure several of the Lyman lines of the N-like ions. The lines' profiles are unresolved at the limited signal-to-noise ratio of the data. Our analysis of the zeroth-order image in a companion paper constrains the size of the emission region to be 20-60 pc, suggesting that emission within this volume is almost entirely due to the reprocessing of the obscured central source. Here we show that a model containing two distinct components can reproduce almost all the observed properties of this gas. The ionized component can explain the observed intensities of the ionized species, assuming twice-solar composition and an N is proportional r(exp -1.5) density distribution. The neutral component is highly concentrated, well within the 0.8" point source, and is responsible for almost all of the observed K(alpha) (6.4 keV) emission. Circinus seems to be different than Mkn 3 in terms of its gas distribution.

  15. Structure of the Circumnuclear Region of Seyfert 2 Galaxies Revealed by RXTE Hard X-Ray Observations of NGC 4945

    NASA Technical Reports Server (NTRS)

    Madejski, G.; Zycki, P.; Done, C.; Valinia, A.; Blanco, P.; Rothschild, R.; Turek, B.

    2000-01-01

    NGC 4945 is one of the brightest Se.yfert galaxies on the sky at 100 keV, but is completely absorbed below 10 keV, implying an optical depth of the absorber to electron scattering of a few; its absorption column is probably the largest which still allows a direct view of the nucleus at hard X-ray energies. Our observations of it with the Rossi X-ray Timing Explorer (RXTE) satellite confirm the large absorption, which for a simple phenomenological fit using an absorber with Solar abundances implies a column of 4.5(sup 0.4, sub -0.4) x 10(exp 24) /sq cm. Using a a more realistic scenario (requiring Monte Carlo modeling of the scattering), we infer the optical depth to Thomson scattering of approximately 2.4. If such a scattering medium were to subtend a large solid angle from the nucleus, it should smear out any intrinsic hard X-ray variability on time scales shorter than the light travel time through it. The rapid (with a time scale of approximately a day) hard X-ray variability of NGC 4945 we observed with the RXTE implies that the bulk of the extreme absorption in this object does not originate in a parsec-size, geometrically thick molecular torus. Limits on the amount of scattered flux require that the optically thick material on parsec scales must be rather geometrically thin, subtending a half-angle < 10 deg. This is only marginally consistent with the recent determinations of the obscuring column in hard X-rays, where only a quarter of Seyfert 2s have columns which are optically thick, and presents a problem in accounting for the Cosmic X-ray Background primarily with AGN possessing the geometry as that inferred by us. The small solid angle of the obscuring material, together with the black hole mass (of approximately 1.4 x 10(exp 6) solar mass) from megamaser measurements. allows a robust determination of the source luminosity, which in turn implies that the source radiates at approximately 10% of the Eddington limit.

  16. High-Resolution Ultraviolet Spectra of the Dwarf Seyfert 1 Galaxy NGC 4395: Evidence for Intrinsic Absorption

    NASA Astrophysics Data System (ADS)

    Crenshaw, D. M.; Kraemer, S. B.; Gabel, J. R.; Schmitt, H. R.; Filippenko, A. V.; Ho, L. C.; Shields, J. C.; Turner, T. J.

    2004-09-01

    We present ultraviolet spectra of the dwarf Seyfert 1 nucleus of NGC 4395, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope Space Telescope Imaging Spectrograph at velocity resolutions of 7-15 km s-1. We confirm our earlier claim of C IV absorption in low-resolution UV spectra and detect a number of other absorption lines with lower ionization potentials. In addition to the Galactic lines, we identify two kinematic components of absorption that are likely to be intrinsic to NGC 4395. We consider possible origins of the absorption, including the interstellar medium (ISM) of NGC 4395, the narrow-line region, the outflowing UV absorbers, and the X-ray ``warm absorbers.'' Component 1, at a radial velocity of -770 km s-1 with respect to the nucleus, is only identified in the C IV λ1548.2 line. It most likely represents an outflowing UV absorber, similar to those seen in a majority of Seyfert 1 galaxies, although additional observations are needed to confirm the reality of this feature. Component 2, at -114 km s-1, most likely arises in the ISM of NGC 4395; its ionic column densities cannot be matched by photoionization models with a power-law continuum. Our models of the highly ionized X-ray absorbers claimed for this active galactic nucleus indicate that they would have undetectable C IV absorption, but large O VI and H I columns should be present. We attribute our lack of detection of the O VI and Lyβ absorption from the X-ray absorbers to a combination of noise and dilution of the nuclear spectrum by hot stars in the large FUSE aperture. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555 these observations are associated with proposal GO-9362. Also based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer

  17. A Comprehensive Study of 2000 Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey. I. The Sample

    NASA Astrophysics Data System (ADS)

    Zhou, Hongyan; Wang, Tinggui; Yuan, Weimin; Lu, Honglin; Dong, Xiaobo; Wang, Junxian; Lu, Youjun

    2006-09-01

    This is the first paper in a series dedicated to the study of the emission-line and continuum properties of narrow line Seyfert 1 galaxies (NLS1s). We carried out a systematic search for NLS1s from objects assigned as ``QSOs'' or ``galaxies'' in the spectroscopic sample of the Sloan Digital Sky Survey Data Release 3 (SDSS DR3) by a careful modeling of their emission lines and continua. The result is a uniform sample comprising ~2000 NLS1s. This sample dramatically increases the number of known NLS1s by a factor of ~10 over previous compilations. This paper presents the parameters of the prominent emission lines and continua, which were measured accurately with typical uncertainties <10%. Taking advantage of such an unprecedented large and uniform sample with accurately measured spectral parameters, we carried out various statistical analyses, some of which were only possible for the first time. The main results found are as follows. (1) Within the overall Seyfert 1 population, the incidence of NLS1s is strongly dependent on the optical, X-ray, and radio luminosities as well as the radio loudness. The fraction of NLS1s peaks around SDSS g-band absolute magnitude Mg~-22 mag in the optical and ~1043.2 ergs s-1 in the soft X-ray band, and decreases quickly as the radio loudness increases. (2) On average the relative Fe II emission, R4570=Fe II λλ4434-4684/Hβ, in NLS1s is about twice that in normal active galactic nuclei (AGNs) and is anticorrelated with the broad component width of the Balmer emission lines. (3) The well-known anticorrelation between the width of broad low-ionization lines and the soft X-ray spectral slope for broad line AGNs extends down to FWHM~1000 km s-1 in NLS1s, but the trend appears to reverse at still smaller line widths. (4) The equivalent width of Hβ and Fe II emission lines are strongly correlated with the Hβ and continuum luminosities. (5) We do not find any difference between NLS1s and normal AGNs in regard to the narrow line region

  18. Catalogue of the morphological features in the Spitzer Survey of Stellar Structure in Galaxies (S4G)

    NASA Astrophysics Data System (ADS)

    Herrera-Endoqui, M.; Díaz-García, S.; Laurikainen, E.; Salo, H.

    2015-10-01

    Context. A catalogue of the features for the complete Spitzer Survey of Stellar Structure in Galaxies (S4G), including 2352 nearby galaxies, is presented. The measurements are made using 3.6 μm images, largely tracing the old stellar population; at this wavelength the effects of dust are also minimal. The measured features are the sizes, ellipticities, and orientations of bars, rings, ringlenses, and lenses. Measured in a similar manner are also barlenses (lens-like structures embedded in the bars), which are not lenses in the usual sense, being rather the more face-on counterparts of the boxy/peanut structures in the edge-on view. In addition, pitch angles of spiral arm segments are measured for those galaxies where they can be reliably traced. More than one pitch angle may appear for a single galaxy. All measurements are made in a human-supervised manner so that attention is paid to each galaxy. Aims: We create a catalogue of morphological features in the complete S4G. Methods: We used isophotal analysis, unsharp masking, and fitting ellipses to measured structures. Results: We find that the sizes of the inner rings and lenses normalized to barlength correlate with the galaxy mass: the normalized sizes increase toward the less massive galaxies; it has been suggested that this is related to the larger dark matter content in the bar region in these systems. Bars in the low mass galaxies are also less concentrated, likely to be connected to the mass cut-off in the appearance of the nuclear rings and lenses. We also show observational evidence that barlenses indeed form part of the bar, and that a large fraction of the inner lenses in the non-barred galaxies could be former barlenses in which the thin outer bar component has dissolved. Full Tables 2 and 3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/582/A86

  19. THICK DISKS OF EDGE-ON GALAXIES SEEN THROUGH THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G): LAIR OF MISSING BARYONS?

    SciTech Connect

    Comeron, Sebastien; Elmegreen, Bruce G.; Knapen, Johan H.; Salo, Heikki; Laine, Jarkko; Laurikainen, Eija; Athanassoula, E.; Bosma, Albert; Hinz, Joannah L.; De Paz, Armando Gil; Menendez-Delmestre, KarIn; Seibert, Mark; Ho, Luis C.; Elmegreen, Debra M.; Gadotti, Dimitri A.

    2011-11-01

    Most, if not all, disk galaxies have a thin (classical) disk and a thick disk. In most models thick disks are thought to be a necessary consequence of the disk formation and/or evolution of the galaxy. We present the results of a study of the thick disk properties in a sample of carefully selected edge-on galaxies with types ranging from T = 3 to T = 8. We fitted one-dimensional luminosity profiles with physically motivated functions-the solutions of two stellar and one gaseous isothermal coupled disks in equilibrium-which are likely to yield more accurate results than other functions used in previous studies. The images used for the fits come from the Spitzer Survey of Stellar Structure in Galaxies (S{sup 4}G). We found that thick disks are on average more massive than previously reported, mostly due to the selected fitting function. Typically, the thin and thick disks have similar masses. We also found that thick disks do not flare significantly within the observed range in galactocentric radii and that the ratio of thick-to-thin disk scale heights is higher for galaxies of earlier types. Our results tend to favor an in situ origin for most of the stars in the thick disk. In addition, the thick disk may contain a significant amount of stars coming from satellites accreted after the initial buildup of the galaxy and an extra fraction of stars coming from the secular heating of the thin disk by its own overdensities. Assigning thick disk light to the thin disk component may lead to an underestimate of the overall stellar mass in galaxies because of different mass-to-light ratios in the two disk components. On the basis of our new results, we estimate that disk stellar masses are between 10% and 50% higher than previously thought and we suggest that thick disks are a reservoir of 'local missing baryons'.

  20. BREAKS IN THIN AND THICK DISKS OF EDGE-ON GALAXIES IMAGED IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

    SciTech Connect

    Comeron, Sebastien; Salo, Heikki; Laurikainen, Eija; Laine, Jarkko; Elmegreen, Bruce G.; Athanassoula, E.; Bosma, Albert; Knapen, Johan H.; Gadotti, Dimitri A.; Sheth, Kartik; Munoz-Mateos, Juan Carlos; Kim, Taehyun; Hinz, Joannah L.; Regan, Michael W.; Gil de Paz, Armando; Menendez-Delmestre, Karin; Seibert, Mark; Ho, Luis C.; Mizusawa, Trisha; Holwerda, Benne

    2012-11-10

    Breaks in the radial luminosity profiles of galaxies have until now been mostly studied averaged over disks. Here, we study separately breaks in thin and thick disks in 70 edge-on galaxies using imaging from the Spitzer Survey of Stellar Structure in Galaxies. We built luminosity profiles of the thin and thick disks parallel to midplanes and we found that thin disks often truncate (77%). Thick disks truncate less often (31%), but when they do, their break radius is comparable with that in the thin disk. This suggests either two different truncation mechanisms-one of dynamical origin affecting both disks simultaneously and another one only affecting the thin disk-or a single mechanism that creates a truncation in one disk or in both depending on some galaxy property. Thin disks apparently antitruncate in around 40% of galaxies. However, in many cases, these antitruncations are an artifact caused by the superposition of a thin disk and a thick disk, with the latter having a longer scale length. We estimate the real thin disk antitruncation fraction to be less than 15%. We found that the ratio of the thick and thin stellar disk mass is roughly constant (0.2 < M{sub T} /M{sub t} < 0.7) for circular velocities v{sub c} > 120 km s{sup -1}, but becomes much larger at smaller velocities. We hypothesize that this is due to a combination of a high efficiency of supernova feedback and a slower dynamical evolution in lower-mass galaxies causing stellar thin disks to be younger and less massive than in higher-mass galaxies.

  1. A Uniformly Selected Sample of Low-mass Black Holes in Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Dong, Xiao-Bo; Ho, Luis C.; Yuan, Weimin; Wang, Ting-Gui; Fan, Xiaohui; Zhou, Hongyan; Jiang, Ning

    2012-08-01

    We have conducted a systematic search of low-mass black holes (BHs) in active galactic nuclei (AGNs) with broad Hα emission lines, aiming at building a homogeneous sample that is more complete than previous ones for fainter, less highly accreting sources. For this purpose, we developed a set of elaborate, automated selection procedures and applied it uniformly to the Fourth Data Release of the Sloan Digital Sky Survey. Special attention is given to AGN-galaxy spectral decomposition and emission-line deblending. We define a sample of 309 type 1 AGNs with BH masses in the range 8 × 104-2 × 106 M ⊙ (with a median of 1.2 × 106 M ⊙), using the virial mass estimator based on the broad Hα line. About half of our sample of low-mass BHs differs from that of Greene & Ho, with 61 of them discovered here for the first time. Our new sample picks up more AGNs with low accretion rates: the Eddington ratios of the present sample range from <~ 0.01 to ~1, with 30% below 0.1. This suggests that a significant fraction of low-mass BHs in the local universe are accreting at low rates. The host galaxies of the low-mass BHs have luminosities similar to those of L* field galaxies, optical colors of Sbc spirals, and stellar spectral features consistent with a continuous star formation history with a mean stellar age of less than 1 Gyr.

  2. New H2O masers in Seyfert and FIR bright galaxies. III. The southern sample

    NASA Astrophysics Data System (ADS)

    Surcis, G.; Tarchi, A.; Henkel, C.; Ott, J.; Lovell, J.; Castangia, P.

    2009-08-01

    Context: A relationship between the water maser detection rate and far infrared (FIR) flux densities was established as a result of two 22 GHz maser surveys in a complete sample of galaxies ({Dec>-30°) with {100 μ m} flux densities of >50 Jy and >30 Jy. Aims: We attempted to discover new maser sources and investigate the galaxies hosting the maser spots by extending previous surveys to southern galaxies with particular emphasis on the study of their nuclear regions. Methods: A sample of 12 galaxies with {Dec<-30° and S100 μ m>50 Jy was observed with the 70-m telescope of the Canberra deep space communication complex (CDSCC) at Tidbinbilla (Australia) in a search for water maser emission. The average 3σ noise level of the survey was 15 mJy for a {0.42 km s-1} channel, corresponding to a detection threshold of ˜ 0.1 L⊙ for the isotropic maser luminosity at a distance of 25 Mpc. Results: Two new detections are reported: a kilomaser with an isotropic luminosity L{H2O}˜5 L⊙ in NGC 3620 and a maser with about twice this luminosity in the merger system NGC 3256. The detections have been followed-up by continuum and spectral line interferometric observations with the Australia Telescope Compact Array (ATCA). In NGC 3256, a fraction (about a third) of the maser emission originates in two hot spots associated with star formation activity, which are offset from the galactic nuclei of the system. The remaining emission may originate in weaker centres of maser activity distributed over the central 50''. For NGC 3620, the water maser is coincident with the nuclear region of the galaxy. Our continuum observations indicate that the nature of the nuclear emission is probably linked to particularly intense star formation. Including the historical detection in NGC 4945, the water maser detection rate in the southern sample is 15% (3/20), consistent with the northern sample. The high rate of maser detections in the complete all-sky FIR sample (23%, 15/65) confirms the

  3. Far Ultraviolet Spectroscopic Explorer Observations of the Seyfert 1.5 Galaxy NGC 5548 in a Low State

    NASA Technical Reports Server (NTRS)

    Brotherton, M. S.; Green, R. F.; Kriss, G. A.; Oegerle, W.; Kaiser, M. E.; Zheng, W.; Hutchings, J. B.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We present far-ultraviolet spectra of the Seyfert 1.5 galaxy NGC 5548 obtained in 2000 June with the Far Ultraviolet Spectroscopic Explorer (FUSE). Our data span the observed wavelength range 915-1185 A at a resolution of approximately 20 km s(exp -1). The spectrum shows a weak continuum and emission from O VI (lambda)(lambda)1032, 1038, C III (lambda)977, and He II (lambda)1085. The FUSE data were obtained when the AGN (Active Galactic Nuclei) was in a low state, which has revealed strong, narrow O VI emission lines. We also resolve intrinsic, associated absorption lines of O VI and the Lyman series. Several distinct kinematic components are present, spanning a velocity range of approximately 0 to -1300 km s(exp -1) relative to systemic, with kinematic structure similar to that seen in previous observations of longer wavelength ultraviolet (UV) lines. We explore the relationships between the far-UV (ultraviolet) absorbers and those seen previously in the UV and X-rays. We find that the high-velocity UV absorption component is consistent with being low-ionization, contrary to some previous claims, and is consistent with its non-detection in high-resolution X-ray spectra. The intermediate velocity absorbers, at -300 to -400 km s(exp -1), show H I and O VI column densities consistent with having contributions from both a high-ionization X-ray absorber and a low-ionization UV absorber. No single far-UV absorbing component can be solely identified with the X-ray absorber.

  4. A SUZAKU DISCOVERY OF A SLOWLY VARYING HARD X-RAY CONTINUUM FROM THE TYPE I SEYFERT GALAXY NGC 3516

    SciTech Connect

    Noda, Hirofumi; Makishima, Kazuo; Nakazawa, Kazuhiro; Yamada, Shin'ya

    2013-07-10

    The bright type I Seyfert galaxy NGC 3516 was observed by Suzaku twice, in 2005 October 12-15 and 2009 October 28-November 2, for a gross time coverage of 242 and 544 ks and a net exposure of 134 and 255 ks, respectively. The 2-10 keV luminosity was 2.8 Multiplication-Sign 10{sup 41} erg s{sup -1} in 2005 and 1.6 Multiplication-Sign 10{sup 41} erg s{sup -1} in 2009. The 1.4-1.7 keV and 1.7-10 keV count rates both exhibited peak-to-peak variations of a factor of {approx}2 in 2005 and {approx}4 in 2009. In both observations, the 15-45 keV count rate was less variable. The 2-10 keV spectrum in 2005 was significantly more convex than that in 2009. Through a count-count plot technique, the 2-45 keV signals in both sets of data were successfully decomposed in a model-independent way into two distinct broadband components. One is a variable emission with a featureless spectral shape, and the other is a non-varying hard component accompanied by a prominent Fe-K emission line at 6.33 keV (6.40 keV in the rest frame). The former was successfully fitted by an absorbed power-law model, while the latter requires a new hard continuum in addition to a reflection component from distant materials. The spectral and variability differences between the two observations are mainly attributed to long-term changes of this new hard continuum, which was stable on timescales of several hundreds of kiloseconds.

  5. The Swift Burst Alert Telescope Detected Seyfert 1 Galaxies: X-Ray Broadband Properties and Warm Absorbers

    NASA Technical Reports Server (NTRS)

    Winter, Lisa M.; Veilleux, Sylvain; McKernan, Barry; Kallman, T.

    2012-01-01

    We present results from an analysis of the broadband, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey conducted in the 14-195 keV band. Therefore, our sources are largely unbiased toward both obscuration and host galaxy properties. Our detailed and uniform model fits to Suzaku/BAT and XMM-Newton/BAT spectra include the neutral absorption, direct power-law, reflected emission, soft excess, warm absorption, and narrow Fe I K[alpha] emission properties for the entire sample. We significantly detect O VII and O VIII edges in 52% of our sample. The strength of these detections is strongly correlated with the neutral column density measured in the spectrum. Among the strongest detections, X-ray grating and UV observations, where available, indicate outflowing material. The ionized column densities of sources with O VII and O VIII detections are clustered in a narrow range with Nwarm [approx] 1021 cm-2, while sources without strong detections have column densities of ionized gas an order of magnitude lower. Therefore, we note that sources without strong detections likely have warm ionized outflows present but at low column densities that are not easily probed with current X-ray observations. Sources with strong complex absorption have a strong soft excess, which may or may not be due to difficulties in modeling the complex spectra of these sources. Still, the detection of a flat [Gamma] [approx] 1 and a strong soft excess may allow us to infer the presence of strong absorption in low signal-to-noise active galactic nucleus spectra. Additionally, we include a useful correction from the Swift BAT luminosity to bolometric luminosity, based on a comparison of our spectral fitting results with published spectral energy distribution fits from 33 of our sources.

  6. [O III] line properties in two samples of radio-emitting narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Berton, M.; Foschini, L.; Ciroi, S.; Cracco, V.; La Mura, G.; Di Mille, F.; Rafanelli, P.

    2016-06-01

    The [O III] λλ 4959, 5007 lines are a useful proxy to test the kinematic of the narrow-line region (NLR) in active galactic nuclei (AGN). In AGN, and particularly in narrow-line Seyfert 1 galaxies (NLS1s) these lines often show few peculiar features, such as blue wings, often interpreted as outflowing component, and a shift - typically toward lower wavelengths - of the whole spectroscopic feature in some exceptional sources, the so-called blue outliers, which are often associated to strong winds. We investigated the incidence of these peculiarities in two samples of radio-emitting NLS1s, one radio-loud and one radio-quiet. We also studied a few correlations between the observational properties of the [O III] lines and those of the AGN. Our aim was to understand the difference between radio-quiet and radio-loud NLS1s, which may in turn provide useful information on the jet formation mechanism. We find that the NLR gas is much more perturbed in radio-loud than in radio-quiet NLS1s. In particular the NLR dynamics in γ-ray emitting NLS1s appears to be highly disturbed, and this might be a consequence of interaction with the relativistic jet. The less frequently perturbed NLR in radio-quiet NLS1s suggests instead that these sources likely do not harbor a fully developed relativistic jet. Nonetheless blue-outliers in radio-quiet NLS1s are observed, and we interpret them as a product of strong winds.

  7. Relativistic Iron K Emission and Absorption in the Seyfert 1.9 Galaxy MCG-05-23-16

    NASA Technical Reports Server (NTRS)

    Braito, V.; Reeves, J. N.; Dewangan, G. C.; George, I.; Griffiths, R.; Markowitz, A.; Nandra, K.; Porquet, D.; Ptak, A.; Turner, T. J.; Yaqoob, T.; Weaver, K.

    2007-01-01

    We present the results of the simultaneous deep XMM-Newton and Chandra observations of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of the best known examples of a relativistically broadened iron Kalpha line. We detected a narrow sporadic absorption line at 7.7 keV which appears to be variable on a time-scale of 20 ksec. If associated with FeXXVI this absorption is indicative of a possible variable high ionization, high velocity outflow. The time averaged spectral analysis shows that the iron K-shell complex is best modeled with an unresolved narrow emission component (FWHM less than 5000 kilometers per second, EW approx. 60 eV) plus a broad component. This latter component has FWHM approx. 44000 kilometers per second, an EW approx. 50 eV and its profile is well described with an emission line originating from the accretion disk viewed with an inclination angle approx. 40 deg. and with the emission arising from within a few tens of gravitational radii of the central black hole. The time-resolved spectral analysis of the XMM-Newton EPIC-pn spectrum shows that both the narrow and broad components of the Fe K emission line appear to be constant within the errors. The analysis of the XMM-Newton/RGS spectrum reveals that the soft X-ray emission of MCG-5-23-16 is likely dominated by several emission lines superimposed on an unabsorbed scattered power-law continuum. The lack of strong Fe L shell emission together with the detection of a strong forbidden line in the O VII triplet supports a scenario where the soft X ray emission lines are produced in a plasma photoionized by the nuclear emission.

  8. Peek-a-boo: Mapping Dust in Galaxies with Spitzer IRAC Imaging of Back-lit Galaxy Pairs

    NASA Astrophysics Data System (ADS)

    Kulkarni, Varsha; Higdon, Sarah; Higdon, James

    2010-06-01

    Interstellar dust affects the chemistry and energy budget of galaxies, and can profoundly affect studies of the distant universe. However, very little is known about the nature of interstellar dust in normal galaxies beyond the Milky Way and the Magellanic Clouds. A direct way to probe dust in galaxies is by using partially overlapping (backlit) pairs of galaxies. While this technique has been applied to a few galaxy pairs, it has been used primarily with optical data in B and I bands (and occasionally K band), which are all subject to substantial amounts of dust extinction. Here we propose to observe 15 backlit pairs/polar ring galaxies in IRAC 3.6 and 4.5 micron bands which are much less affected by dust. Our goals are: (1) to obtain essentially un-extinguished reference images for comparison with the existing optical images and thus to determine dust extinction more accurately across different parts of the foreground galaxies; (2) to determine the opacity of some nearby spiral disks and examine whether dust grain sizes decrease in outer parts of disks; (3) to probe large-scale dust structure in some elliptical galaxies; (4) to examine whether dust exhibits fractal structure; and (5) to map star formation rate across the galaxies using the 3.6/4.5 micron flux ratio. The very local nature of our sample allows a detailed look at dust properties at different positions within the galaxies, and examine what galaxy properties drive the variation in dust properties. Our study will provide new implications for observations of the distant universe that are necessarily affected by the presence of dust in foreground galaxies.

  9. MEASURING THE STELLAR MASSES OF z ∼ 7 GALAXIES WITH THE SPITZER ULTRAFAINT SURVEY PROGRAM (SURFS UP)

    SciTech Connect

    Ryan, R. E. Jr.; Casertano, S.; Stiavelli, M.; Gonzalez, A. H.; Lemaux, B. C.; Bradač, M.; Cain, B.; Hall, N.; Huang, K.-H.; Lubin, L.; Allen, S.; Von der Linden, A.; Gladders, M.; Hildebradt, H.; Schrabback, T.; Hinz, J.; Zaritsky, D.; Treu, T.

    2014-05-01

    We present Spitzer/IRAC observations of nine z'-band dropouts highly magnified (2 ≲ μ ≲ 12) by the Bullet Cluster. We combine archival imaging with our Exploratory program (SURFS UP), which results in a total integration time of ∼30 hr per Infrared Array Camera (IRAC) band. We detect (≳ 3σ) in both IRAC bands the brightest of these high-redshift galaxies, with [3.6] = 23.80 ± 0.28 mag, [4.5] = 23.78 ± 0.25 mag, and (H – [3.6]) = 1.17 ± 0.32 mag. The remaining eight galaxies are undetected to [3.6] ∼ 26.4 mag and [4.5] ∼ 26.0 mag with stellar masses of ∼5 × 10{sup 7} M {sub ☉}. The detected galaxy has an estimated magnification of μ = 12 ± 4, which implies this galaxy has an ultraviolet luminosity of L{sub 1500}∼0.3 L{sub z=7}{sup ∗}—the lowest-luminosity individual source detected in IRAC at z ≳ 7. By modeling the broadband photometry, we estimate the galaxy has an intrinsic star formation rate (SFR) of SFR ∼ 1.3 M {sub ☉} yr{sup –1} and stellar mass of M ∼ 2.0 × 10{sup 9} M {sub ☉}, which gives a specific star formation rate of sSFR ∼ 0.7 Gyr{sup –1}. If this galaxy had sustained this SFR since z ∼ 20, it could have formed the observed stellar mass (to within a factor of ∼2). We also discuss alternate star formation histories and argue that the exponentially increasing model is unlikely. Finally, based on the intrinsic SFR, we estimate that this galaxy has a likely [C II] flux of (f {sub [C} {sub II]}) = 1.6 mJy.

  10. MID-INFRARED GALAXY MORPHOLOGY FROM THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G): THE IMPRINT OF THE DE VAUCOULEURS REVISED HUBBLE-SANDAGE CLASSIFICATION SYSTEM AT 3.6 {mu}m

    SciTech Connect

    Buta, Ronald J.; Sheth, Kartik; Aravena, Manuel; Hinz, Joannah L.; Gil de Paz, Armando; Munoz-Mateos, Juan-Carlos; Laurikainen, Eija; Salo, Heikki; Gadotti, Dimitri A.; Athanassoula, E.; Bosma, Albert; Elmegreen, Debra M.; Masters, Karen L.; Comeron, Sebastien

    2010-09-15

    Spitzer Space Telescope Infrared Array Camera imaging provides an opportunity to study all known morphological types of galaxies in the mid-IR at a depth significantly better than ground-based near-infrared and optical images. The goal of this study is to examine the imprint of the de Vaucouleurs classification volume in the 3.6 {mu}m band, which is the best Spitzer waveband for galactic stellar mass morphology owing to its depth and its reddening-free sensitivity mainly to older stars. For this purpose, we have prepared classification images for 207 galaxies from the Spitzer archive, most of which are formally part of the Spitzer Survey of Stellar Structure in Galaxies (S{sup 4}G), a Spitzer post-cryogenic ('warm') mission Exploration Science Legacy Program survey of 2331 galaxies closer than 40 Mpc. For the purposes of morphology, the galaxies are interpreted as if the images are blue light, the historical waveband for classical galaxy classification studies. We find that 3.6 {mu}m classifications are well correlated with blue-light classifications, to the point where the essential features of many galaxies look very similar in the two very different wavelength regimes. Drastic differences are found only for the most dusty galaxies. Consistent with a previous study by Eskridge et al., the main difference between blue-light and mid-IR types is an {approx}1 stage interval difference for S0/a to Sbc or Sc galaxies, which tend to appear 'earlier' in type at 3.6 {mu}m due to the slightly increased prominence of the bulge, the reduced effects of extinction, and the reduced (but not completely eliminated) effect of the extreme population I stellar component. We present an atlas of all of the 207 galaxies analyzed here and bring attention to special features or galaxy types, such as nuclear rings, pseudobulges, flocculent spiral galaxies, I0 galaxies, double-stage and double-variety galaxies, and outer rings, that are particularly distinctive in the mid-IR.

  11. Measuring the Fraction of Bars and Offset Bars Using the Spitzer Survey of Stellar Structure in Galaxies

    NASA Astrophysics Data System (ADS)

    Ross, Alexa

    2012-01-01

    Using the Spitzer Survey of Stellar Structure in Galaxies at 3.6 and 4.5μm, I have measured a preliminary bar fraction and offset bar fraction in the local universe by visually identifying bar structure within a sample of 2,140 local galaxies. A sample this large has not been used since 1963, when Gerard de Vaucouleurs found the bar fraction to be roughly fbar ˜ 0.6 in the Third Reference Catalog of Bright Galaxies. Since then, there has been much debate over the true value of the bar fraction. The purpose of finding a bar fraction using S4G is to provide a final say in this debate. I have found that the bar fraction in the local universe is fbar = 0.69 when including both definite bars (SB) and candidate bars (SAB). I have also measured a preliminary value for the fraction of offset bars using the same sample. Offset bars are a very rare phenomenon. Of the sample used, 91 galaxies are found to be definite offset bars while an additional 39 are found to be candidate offset bars. When including both definite offset bars and candidate offset bars, the offset bar fraction in the local universe becomes fob = 0.12. I also measure the fraction of offset bars as a function of Hubble type and stellar mass. We find that 54% of offset bars are found in disks having a stellar mass of M ≤ 108 M⊙. Late-type disks possess significantly more offset bars than early-type with 60% of offset bars being found in disks having a Hubble type t ≥ 6.

  12. The mass of the central black hole in the nearby Seyfert galaxy NGC 5273

    SciTech Connect

    Bentz, Misty C.; Horenstein, Daniel; Bazhaw, Craig; Manne-Nicholas, Emily R.; Ou-Yang, Benjamin J.; Anderson, Matthew; Jones, Jeremy; Norris, Ryan P.; Parks, J. Robert; Saylor, Dicy; Teems, Katherine G.; Turner, Clay

    2014-11-20

    We present the results of a reverberation-mapping program targeting NGC 5273, a nearby early-type galaxy with a broad-lined active galactic nucleus (AGN). Over the course of the monitoring program, NGC 5273 showed strong variability that allowed us to measure time delays in the responses of the broad optical recombination lines to changes in the continuum flux. A weighted average of these measurements results in a black hole mass determination of M {sub BH} = (4.7 ± 1.6) × 10{sup 6} M {sub ☉}. An estimate of the size of the black hole sphere of influence in NGC 5273 puts it just at the limit of the resolution achievable with current ground-based large aperture telescopes. NGC 5273 is therefore an important future target for a black hole mass determination from stellar dynamical modeling, especially because it is the only nearby early-type galaxy hosting an AGN with a reverberation-based mass, allowing the best comparison for the masses determined from these two techniques.

  13. The X-ray Reflectors in the Nucleus of the Seyfert Galaxy NGC 1068

    NASA Technical Reports Server (NTRS)

    Colbert, Edward J. M.; Weaver, Kimberly A.; Krolik, Julian H.; Mulchaey, John S.; Mushotzky, Richard F.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    Based on observations of the Seyfert nucleus in NGC 1068 with ASCA, RXTE and BeppoSAX, we report the discovery of a flare (increase in flux by a factor of approximately 1.6) in the 6.7 keV Fe K line component between observations obtained four months apart, with no significant change in the other (6.21, 6.4, and 6.97 keV) Fe Kalpha line components. During this time, the continuum flux decreased by approximately 20%. The RXTE spectrum requires an Fe K absorption edge near 8.6 keV (Fe XXIII- XXV). The spectral data indicate that the 2-10 keV continuum emission is dominated (approximately 2/3 of the luminosity) by reflection from a previously unidentified region of warm, ionized gas located approximately or less than 0.2 pc from the AGN. The remaining approximately 1/3 of the observed X-ray emission is reflected from optically thick, neutral gas. The coronal gas in the inner Narrow-Line Region (NLR) and/or the cold gas at the inner surface of the obscuring 'torus' are possible cold reflectors. The inferred properties of the warm reflector are: size (diameter) approximately or less than 0.2 pc, gas density n approximately or greater than 10(exp 5.5)/cu cm, ionization parameter xi is approximately 10(exp 3.5) erg cm s(exp -1), and covering fraction 0.003 (L(sub 0)/ 10(exp 43.5) erg s(exp -1)(exp -1) less than (omega/4pi) less than 0.024 (L(sub 0)/ 10(exp 43.5) erg s(exp -1) (exp -1) where L(sub 0) is the intrinsic 2-10 keV X-ray luminosity of the AGN. We suggest that the warm reflector gas is the source of the (variable) 6.7 keV Fe line emission, and the 6.97 keV Fe line emission. The 6.7 keV line flare is assumed to be due to an increase in the emissivity of the warm reflector gas from a decrease (by 20-30%) in L(sub 0). The properties of the warm reflector are most consistent with an intrinsically X-ray weak AGN with L(sub 0) approximately equals 10(exp 43.0) erg s(exp -1). The optical and UV emission that scatters from the warm reflector into our line of sight is

  14. A Stellar Dynamical Black Hole Mass for Broad-Lined Seyfert Galaxy NGC 6814 and Comparison to Results from Reverberation Mapping

    NASA Astrophysics Data System (ADS)

    Manne-Nicholas, Emily; Batiste, Merida; Valluri, Monica; Bentz, Misty C.; Onken, Christopher A.; Ferrarese, Laura

    2016-01-01

    We present a stellar dynamical mass for the supermassive black hole in the nearby (z=0.005) broad-lined Seyfert galaxy NGC 6814 and compare it to the published reverberation-based mass. NGC 6814 is only the third galaxy for which the comparison of these two techniques has been accomplished in the same galaxy. Though stellar dynamical modeling is currently thought to be the most direct way of measuring a SMBH mass, it is quite limited because it can only be performed on nearby galaxies that have a spatially resolvable (or nearly so) black hole gravitational sphere of influence. In contrast, reverberation mapping, which relies on time resolution and not spatial resolution, can be used to constrain black hole masses in even the most distant quasars. Reverberation masses, however, carry with them an uncertainty based on the unknown geometry of the photoionized broad line region. This uncertainty affects our ability to accurately measure masses of AGN not just for reverberation masses, but also for the thousands of masses that rely on the reverberation sample for their calibration. This comparison of the mass of the central supermassive black hole in NGC 6814 using both stellar dynamical and reverberation mapping techniques is part of a larger effort to directly compare these techniques in several galaxies. The more galaxies for which this comparison can be performed, the better we will be able to understand the scatter and potential biases in black hole masses and therefore supermassive black hole evolution across cosmic time.

  15. Exploring the Powerful Ionised Wind in the Seyfert Galaxy PG1211+143

    NASA Astrophysics Data System (ADS)

    Pounds, Ken

    2013-10-01

    Highly-ionised high-speed winds in AGN (UFOs) were first detected with XMM-Newton a decade ago, and are now established as a key factor in the study of SMBH accretion, and in the growth and metal enrichment of their host galaxies. However, information on the ionisation and dynamical structure, and the ultimate fate of UFOs remains very limited. We request a 600ks extended XMM-Newton study of the prototype UFO PG1211+143 in AO-13, to obtain high quality EPIC and RGS spectra, to map the flow structure and variability, while seeking evidence for the anticipated interaction with the ISM and possible conversion of the energetic wind to a momentum-driven flow.

  16. PARSEC-SCALE IMAGING OF THE RADIO-BUBBLE SEYFERT GALAXY NGC 6764

    SciTech Connect

    Kharb, P.; O'Dea, C. P.; Axon, D. J.; Robinson, A.; Hota, Ananda; Croston, J. H.; Hardcastle, M. J.; Kraft, R. P.

    2010-11-01

    We have observed the composite active galactic nucleus (AGN)-starburst galaxy NGC 6764 with the Very Long Baseline Array at 1.6 and 4.9 GHz. These observations have detected a 'core-jet' structure and a possible weak counterjet component at 1.6 GHz. The upper limits to the core and jet (1.6-4.9 GHz) spectral index are 0.6 and 0.3, respectively. Taken together with the high brightness temperature of {approx}10{sup 7} K for the core region, the radio emission appears to be coming from a synchrotron jet. At a position angle of {approx}25{sup 0}, the parsec-scale jet seems to be pointing closely toward the western edge of the southern kpc-scale bubble in NGC 6764. A real connection between the parsec- and sub-kpc-scale emission would not only suggest the presence of a curved jet, but also a close link between the AGN jet and the radio bubbles in NGC 6764. We demonstrate that a precessing jet model can explain the radio morphology from parsec to sub-kpc scales, and the model best-fit parameters of jet speed and orientation are fully consistent with the observed jet-to-counterjet surface brightness ratio. The jet however appears to be disrupted on scales of hundreds of parsecs, possibly due to interaction with and entrainment of the interstellar medium gas, which subsequently leads to the formation of bubbles. The jet energetics in NGC 6764 suggest that it would take 12-21 Myr to inflate the (southern) bubble. This timescale corresponds roughly to the starburst episode that took place in NGC 6764 about 15-50 Myr ago, and could be indicative of a close connection between jet formation and the starburst activity in this galaxy.

  17. Spitzer/IRAC Imaging of Exceptionally Bright Cluster-Lensed Submillimeter Galaxies Discovered by the Herschel Lensing Survey

    NASA Astrophysics Data System (ADS)

    Egami, Eiichi; Ebeling, Harald; Rawle, Timothy; Clement, Benjamin; Walth, Gregory; Pereira, Maria; Richard, Johan; Kneib, Jean-Paul

    2012-12-01

    Over the last few years, discoveries of exceptionally bright (e.g., observed S_peak > 100 mJy in the Herschel/SPIRE bands) gravitationally lensed submillimeter galaxies (SMGs) have generated great excitement. This is because these gravitationally lensed SMGs are so bright that they enable us to perform a variety of follow-up observations using a suite of observing facilities in the submillimeter, millimeter, and radio now available on the ground. Using Herschel, our team has been conducting a survey of such bright lensed galaxies in the fields of massive galaxy clusters: ``The Herschel Lensing Survey (HLS)'' (PI: Egami; 419 hours). This large Herschel program targets a total of 581 X-ray/SZ-selected massive clusters, and is currently 80% complete. Cluster lenses are often more powerful than galaxy lenses, producing larger magnifications. For example, typical magnification factors for galaxy-lensed Herschel sources are x10 or less while cluster-lensed systems can often produce magnification factors of x20-30 and even above x100. Cluster lenses will therefore allow us to detect and study intrinsically less-luminous and/or more distant sources with the ability to provide a view of finer-scale (i.e., sub-kpc) structures. Here, we propose to conduct Spitzer/IRAC imaging of 56 bright lensed SMG candidates we have identified in the ~470 HLS cluster fields observed so far. The main scientific goal is twofold: (1) to locate the underlying stellar component, and (2) to study its properties (e.g., stellar mass, specific star-formation rate) by constraining the rest-frame near-infrared SED and comparing with the Herschel and other submillimeter/millimeter data (e.g., SMA, PdB, ALMA, etc.). These rare bright lensed SMGs will allow us to probe the population of heavily dust-obscured vigorously star-forming galaxies at high redshift (z>1), which is thought to play an important role in the cosmic star-formation history of the Universe and yet has been difficult to study due to the

  18. The X-ray Power Density Spectrum of the Seyfert 2 Galaxy NGC 4945: Analysis and Application of the Method of Light Curve Simulations

    SciTech Connect

    Mueller, Martin; /SLAC

    2010-12-16

    The study of the power density spectrum (PDS) of fluctuations in the X-ray flux from active galactic nuclei (AGN) complements spectral studies in giving us a view into the processes operating in accreting compact objects. An important line of investigation is the comparison of the PDS from AGN with those from galactic black hole binaries; a related area of focus is the scaling relation between time scales for the variability and the black hole mass. The PDS of AGN is traditionally modeled using segments of power laws joined together at so-called break frequencies; associations of the break time scales, i.e., the inverses of the break frequencies, with time scales of physical processes thought to operate in these sources are then sought. I analyze the Method of Light Curve Simulations that is commonly used to characterize the PDS in AGN with a view to making the method as sensitive as possible to the shape of the PDS. I identify several weaknesses in the current implementation of the method and propose alternatives that can substitute for some of the key steps in the method. I focus on the complications introduced by uneven sampling in the light curve, the development of a fit statistic that is better matched to the distributions of power in the PDS, and the statistical evaluation of the fit between the observed data and the model for the PDS. Using archival data on one AGN, NGC 3516, I validate my changes against previously reported results. I also report new results on the PDS in NGC 4945, a Seyfert 2 galaxy with a well-determined black hole mass. This source provides an opportunity to investigate whether the PDS of Seyfert 1 and Seyfert 2 galaxies differ. It is also an attractive object for placement on the black hole mass-break time scale relation. Unfortunately, with the available data on NGC 4945, significant uncertainties on the break frequency in its PDS remain.

  19. Fermi/LAT Observations of Swift/BAT Seyfert Galaxies: On the Contribution of Radio-Quiet Active Galactic Nuclei to the Extragalactic gamma-Ray Background

    NASA Technical Reports Server (NTRS)

    Teng, Stacy H.; Mushotzky, Richard F.; Sambruna, Rita M.; Davis, David S.; Reynolds, Christopher S.

    2011-01-01

    We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R(sub X,BAT) where radio-loud objects have logR(sub X,BAT) > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be approx.2x10(exp -11) photons/sq cm/s, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the gamma-ray (1-100 GeV) luminosity of < approx.3x10(exp 41) erg/s. In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

  20. Some implications of revised OI /7990 A/ and OI /11287 A/ branching ratios. [for Orion Nebula, Seyfert galaxy, Arcturus and comets

    NASA Technical Reports Server (NTRS)

    Christensen, A. B.

    1979-01-01

    Recent laboratory, geophysical, and theoretical determinations of the O I (7990 A) and O I (11,287 A) branching ratios indicate that the generally used values based on the NBS transition parameters need revision. The O I (7990 A) branching ratio is about 300 times smaller than the NBS value, and the O I (11,287 A) is about one-quarter as large. The transitions are important in the generation of permitted atomic oxygen spectra in several types of astronomical source, including the Orion Nebula (M42), the Seyfert galaxy NGC 4151, Arcturus, and comets. The absence of the O I (7990 A) emission in M42 and NGC 4151 is consistent with its very small branching ratio, and previous conclusions based on its absence, such as the rejection of starlight excitation in the Seyfert galaxy, require reinvestigation. The reduction of the O I (11,287 A) branching ratio is pertinent to hydrogen L-beta fluorescence excitation of O I (1304 A) and O I (8446 A) emission and requires an upward revision of oxygen production rates in comets.

  1. FERMI/LAT OBSERVATIONS OF SWIFT/BAT SEYFERT GALAXIES: ON THE CONTRIBUTION OF RADIO-QUIET ACTIVE GALACTIC NUCLEI TO THE EXTRAGALACTIC {gamma}-RAY BACKGROUND

    SciTech Connect

    Teng, Stacy H.; Mushotzky, Richard F.; Reynolds, Christopher S.; Sambruna, Rita M.; Davis, David S.

    2011-12-01

    We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R{sub X,BAT} where radio-loud objects have log R{sub X,BAT} > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be {approx}2 Multiplication-Sign 10{sup -11} photons cm{sup -2} s{sup -1}, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the {gamma}-ray (1-100 GeV) luminosity of {approx}< 3 Multiplication-Sign 10{sup 41} erg s{sup -1}. In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

  2. X-ray monitoring of the radio and γ-ray loud Narrow-Line Seyfert 1 Galaxy PKS2004-447

    NASA Astrophysics Data System (ADS)

    Kreikenbohm, A.; Kadler, M.; Wilms, J.; Schulz, R.; Müller, C.; Ojha, R.; Ros, E.; Mannheim, K.; Elsässer, D.

    2013-12-01

    We present preliminary results of the X-ray analysis of XMM-Newton and Swift observations as part of a multi-wavelength monitoring campaign in 2012 of the radio-loud narrow line Seyfert 1 galaxy PKS 2004-447. The source was recently detected in γ-rays by Fermi/LAT among only four other galaxies of that type. The 0:5 - 10 keV X-ray spectrum is well-described by a simple absorbed powerlaw (Γ ˜ 1.6). The source brightness exhibits variability on timescales of months to years with indications for spectral variability, which follows a "bluer-when-brighter" behaviour, similar to blazars.

  3. Spitzer 24 Micron Observations of Optical/Near-Infrared-Selected Extremely Red Galaxies: Evidence for Assembly of Massive Galaxies at Z approximately equal to 1-2?

    NASA Technical Reports Server (NTRS)

    Yan, Lin; Choi, Philip I.; Fadda, D.; Marleau, F. R.; Soifer, B. T.; Im, M.; Armus, L.; Frayer, D. T.; Storrie-Lombardi, L. J.; Thompson, D. J.; Teplitz, H. I.; Helou, G.; Appleton, P. N.; Chapman, S.; Fan, F.; Heinrichsen, I.; Lacy, M.; Shupe, D. L.; Squires, G. K.; Surace, J.; Wilson, G.

    2004-01-01

    We carried out direct measurement of the fraction of dusty sources in a sample of extremely red galaxies with (R - Ks) >= 5.3 mag and Ks < 20:2 mag, using 24 micron data from the Spitzer Space Telescope. Combining deep 24 micron Ks- and R-band data over an area of 64 arcmin(sup 2) in ELAIS N1 of the Spitzer First Look Survey (FLS), we find that 50% +/- 6% of our extremely red object (ERO) sample have measurable 24 micron flux above the 3 (sigma) flux limit of 40 (micro)Jy. This flux limit corresponds to a star formation rate (SFR) of 12 solar masses per year 1, much more sensitive than any previous long-wavelength measurement. The 24 micron-detected EROs have 24 micron/2.2 micron and 24 micron/0.7 micron flux ratios consistent with infrared luminous, dusty sources at z >= 1, and are an order of magnitude too red to be explained by an infrared quiescent spiral or a pure old stellar population at any redshift. Some of these 24 micron-detected EROs could be active galactic nuclei; however, the fraction among the whole ERO sample is probably small, 10%-20%, as suggested by deep X-ray observations as well as optical spectroscopy. Keck optical spectroscopy of a sample of similarly selected EROs in the FLS field suggests that most of the EROs in ELAIS N1 are probably at z 1. The mean 24 micron flux (167 (micro)Jy) of the 24 micron-detected ERO sample roughly corresponds to the rest-frame 12 micron luminosity, (nu)L(nu)(12 micron, of 3x10(exp 10)(deg) solar luminosities at z 1. Using the c IRAS (nu)L(nu)(12 (micron) and infrared luminosity LIR(8-1000 (micron), we infer that the (LIR) of the 24 micron- detected EROs is 3 x 10(exp 11) and 1 x 10(exp 12) solar luminosities at z = 1.0 and similar to that of local luminous infrared galaxies (LIRGs) and ultraluminous infrared galaxies (ULIRGs). The corresponding SFR would be roughly 50-170 solar masses per year. If the timescale of this starbursting phase is on the order of 108 yr as inferred for the local LIRGs and ULIRGs, the

  4. The Complex Physics of Dusty Star-forming Galaxies at High Redshifts as Revealed by Herschel and Spitzer

    NASA Astrophysics Data System (ADS)

    Lo Faro, B.; Franceschini, A.; Vaccari, M.; Silva, L.; Rodighiero, G.; Berta, S.; Bock, J.; Burgarella, D.; Buat, V.; Cava, A.; Clements, D. L.; Cooray, A.; Farrah, D.; Feltre, A.; González Solares, E. A.; Hurley, P.; Lutz, D.; Magdis, G.; Magnelli, B.; Marchetti, L.; Oliver, S. J.; Page, M. J.; Popesso, P.; Pozzi, F.; Rigopoulou, D.; Rowan-Robinson, M.; Roseboom, I. G.; Scott, Douglas; Smith, A. J.; Symeonidis, M.; Wang, L.; Wuyts, S.

    2013-01-01

    We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous infrared galaxies ((U)LIRGs) at z ~ 1 and 2 selected in GOODS-S with 24 μm fluxes between 0.2 and 0.5 mJy. We model the data with a self-consistent physical model (GRASIL) which includes a state-of-the-art treatment of dust extinction and reprocessing. We find that all of our galaxies appear to require massive populations of old (>1 Gyr) stars and, at the same time, to host a moderate ongoing activity of star formation (SFR <= 100 M ⊙ yr-1). The bulk of the stars appear to have been formed a few Gyr before the observation in essentially all cases. Only five galaxies of the sample require a recent starburst superimposed on a quiescent star formation history. We also find discrepancies between our results and those based on optical-only spectral energy distribution (SED) fitting for the same objects; by fitting their observed SEDs with our physical model we find higher extinctions (by ΔA V ~ 0.81 and 1.14) and higher stellar masses (by Δlog(M sstarf) ~ 0.16 and 0.36 dex) for z ~ 1 and z ~ 2 (U)LIRGs, respectively. The stellar mass difference is larger for the most dust-obscured objects. We also find lower SFRs than those computed from L IR using the Kennicutt relation due to the significant contribution to the dust heating by intermediate-age stellar populations through "cirrus" emission (~73% and ~66% of the total L IR for z ~ 1 and z ~ 2 (U)LIRGs, respectively). Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  5. THE COMPLEX PHYSICS OF DUSTY STAR-FORMING GALAXIES AT HIGH REDSHIFTS AS REVEALED BY HERSCHEL AND SPITZER

    SciTech Connect

    Lo Faro, B.; Franceschini, A.; Vaccari, M.; Rodighiero, G.; Feltre, A.; Marchetti, L.; Silva, L.; Berta, S.; Lutz, D.; Magnelli, B.; Bock, J.; Burgarella, D.; Buat, V.; Cava, A.; Clements, D. L.; Cooray, A.; Farrah, D.; Hurley, P.; Solares, E. A. Gonzalez; Magdis, G.; and others

    2013-01-10

    We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous infrared galaxies ((U)LIRGs) at z {approx} 1 and 2 selected in GOODS-S with 24 {mu}m fluxes between 0.2 and 0.5 mJy. We model the data with a self-consistent physical model (GRASIL) which includes a state-of-the-art treatment of dust extinction and reprocessing. We find that all of our galaxies appear to require massive populations of old (>1 Gyr) stars and, at the same time, to host a moderate ongoing activity of star formation (SFR {<=} 100 M {sub Sun} yr{sup -1}). The bulk of the stars appear to have been formed a few Gyr before the observation in essentially all cases. Only five galaxies of the sample require a recent starburst superimposed on a quiescent star formation history. We also find discrepancies between our results and those based on optical-only spectral energy distribution (SED) fitting for the same objects; by fitting their observed SEDs with our physical model we find higher extinctions (by {Delta}A {sub V} {approx} 0.81 and 1.14) and higher stellar masses (by {Delta}log(M {sub *}) {approx} 0.16 and 0.36 dex) for z {approx} 1 and z {approx} 2 (U)LIRGs, respectively. The stellar mass difference is larger for the most dust-obscured objects. We also find lower SFRs than those computed from L {sub IR} using the Kennicutt relation due to the significant contribution to the dust heating by intermediate-age stellar populations through 'cirrus' emission ({approx}73% and {approx}66% of the total L {sub IR} for z {approx} 1 and z {approx} 2 (U)LIRGs, respectively).

  6. An Off-nucleus Nonstellar Black Hole in the Seyfert Galaxy NGC 5252

    NASA Astrophysics Data System (ADS)

    Kim, Minjin; Ho, Luis C.; Wang, Junfeng; Fabbiano, Giuseppina; Bianchi, Stefano; Cappi, Massimo; Dadina, Mauro; Malaguti, Giuseppe; Wang, Chen

    2015-11-01

    We report the discovery of an ultraluminous X-ray source (ULX; CXO J133815.6+043255) in NGC 5252. This ULX is an off-nuclear point source, which is 22″ away from the center of NGC 5252, and has an X-ray luminosity of 1.5 × 1040 erg s-1. It is one of the rare examples of a ULX, which exhibits clear counterparts in radio, optical, and UV bands. A follow-up optical spectrum of the ULX shows strong emission lines. The redshift of the [O iii] emission line coincides with the systematic velocity of NGC 5252, suggesting that the ULX is gravitationally bound to NGC 5252. The flux of [O iii] appears to be correlated with both X-ray and radio luminosity in the same manner as ordinary active galactic nuclei (AGNs), indicating that the [O iii] emission is intrinsically associated with the ULX. Based on the multiwavelength data, we argue that the ULX is unlikely to be a background AGN. A more likely option is an accreting black hole with a mass of ≥slant {10}4 {M}⊙ , which might be a stripped remnant of a merging dwarf galaxy.

  7. Dust in the nuclei of the Seyfert galaxies Markarian 231 and NGC 4151

    SciTech Connect

    Jones, B.; Worrall, D.M.; Rodriguez-Espinosa, J.M.; Stein, W.A.

    1984-09-01

    Observations carried out with a 8-13 micron grating-spectrometer of Mrk 231 and NGC 4151 are reported. The Mrk 231 data can be fitted to various thermal dust emission models or a single power law, with dust extinction. In all the model fits, except for that of graphite and silicon carbide grain emission, a component of silicate absorption of optical depth of not more than 0.7 is required. Confirming published work, the absorption being at the redshift of the low-redshift absorption-line system is ruled out. The high values of silicate optical depth absorption do not give ratios to the galaxy's visual extinction which are comparable to those of galactic H II regions. Weak evidence for a 10-micron absorption feature in NGC 4151 is also reported. This is somewhat contrary to expectation, since the visual extinction of NGC 4151 is lower than that of Mrk 231, and since there is evidence to support a nonthermal rather than thermal dust origin for the infrared continuum emission. 46 references.

  8. ALMA probes the molecular gas reservoirs in the changing-look Seyfert galaxy Mrk 590

    NASA Astrophysics Data System (ADS)

    Koay, J. Y.; Vestergaard, M.; Casasola, V.; Lawther, D.; Peterson, B. M.

    2016-01-01

    We investigate if the active galactic nucleus (AGN) of Mrk 590, whose supermassive black hole was until recently highly accreting, is turning off due to a lack of central gas to fuel it. We analyse new subarcsecond resolution Atacama Large Millimetre/submilllimetre Array maps of the 12CO(3-2) line and 344 GHz continuum emission in Mrk 590. We detect no 12CO(3-2) emission in the inner 150 pc, constraining the central molecular gas mass to M(H2) ≲ 1.6 × 105 M⊙, no more than a typical giant molecular gas cloud, for a CO luminosity to gas mass conversion factor of αCO ˜ 0.8 M⊙ (K km s- 1 pc2)- 1. However, there is still potentially enough gas to fuel the black hole for another 2.6 × 105 yr assuming Eddington-limited accretion. We therefore cannot rule out that the AGN may just be experiencing a temporary feeding break, and may turn on again in the near future. We discover a ring-like structure at a radius of ˜1 kpc, where a gas clump exhibiting disturbed kinematics and located just ˜200 pc west of the AGN, may be refuelling the centre. Mrk 590 does not have significantly less gas than other nearby AGN host galaxies at kpc scales, confirming that gas reservoirs at these scales provide no direct indication of on-going AGN activity and accretion rates. Continuum emission detected in the central 150 pc likely originates from warm AGN-heated dust, although contributions from synchrotron and free-free emission cannot be ruled out.

  9. Mid- and far-infrared luminosity functions and galaxy evolution from multiwavelength Spitzer observations up to z ~ 2.5

    NASA Astrophysics Data System (ADS)

    Rodighiero, G.; Vaccari, M.; Franceschini, A.; Tresse, L.; Le Fevre, O.; Le Brun, V.; Mancini, C.; Matute, I.; Cimatti, A.; Marchetti, L.; Ilbert, O.; Arnouts, S.; Bolzonella, M.; Zucca, E.; Bardelli, S.; Lonsdale, C. J.; Shupe, D.; Surace, J.; Rowan-Robinson, M.; Garilli, B.; Zamorani, G.; Pozzetti, L.; Bondi, M.; de la Torre, S.; Vergani, D.; Santini, P.; Grazian, A.; Fontana, A.

    2010-06-01

    Context. Studies of the infrared (IR) emission of cosmic sources have proven essential to constraining the evolutionary history of cosmic star formation and the gravitational accretion of nuclear black holes, because many of these events occur inside heavily dust-extinguished environments. Aims: The Spitzer Space Telescope has provided a large amount of data to constrain the nature and cosmological evolution of infrared source populations. In the present paper we exploit a large homogeneous dataset to derive a self-consistent picture of IR emission based on the time-dependent λ_eff = 24, 15, 12, and 8 μm monochromatic and bolometric IR luminosity functions (LF) over the full 0 < z < 2.5 redshift range. Methods: Our present analysis is based on a combination of data from deep Spitzer surveys of the VIMOS VLT Deep Survey (VVDS-SWIRE) and GOODS fields. To our limiting flux of S24 = 400 μJy, our sample derived from VVDS-SWIRE includes 1494 sources, and 666 and 904 sources brighter than S24 = 80 μJy are catalogued in GOODS-S and GOODS-N, respectively, for a total area of ~0.9 square degrees. Apart from a few galaxies, we obtain reliable optical identifications and redshifts for all these sources, providing a rich and robust dataset for our luminosity function determination. The final combined reliable sample includes 3029 sources, the fraction with photometric redshifts being 72% over all redshifts and almost all galaxies at z > 1.5. Based on the multiwavelength information available in these areas, we constrain the LFs at 8, 12, 15, and 24 μm. We also infer the total IR luminosities from our best-fit model of the observed SEDs of each source, and use this to derive the bolometric (8-1000 μm) LF and comoving volume emissivity to z ~ 2.5. Results: In the redshift interval 0 < z < 1, the bolometric IR luminosity density evolves as (1 + z)3.8±0.4. Although it is more uncertain at higher-z, our results show a flattening in the IR luminosity density at z > 1. The mean

  10. SUBMILLIMETER LINE SPECTRUM OF THE SEYFERT GALAXY NGC 1068 FROM THE HERSCHEL-SPIRE FOURIER TRANSFORM SPECTROMETER

    SciTech Connect

    Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma; Schirm, Maximilien R. P.; Wilson, Christine D.; Parkin, Tara J.; Glenn, Jason; Kamenetzky, Julia; Rangwala, Naseem; Maloney, Philip R.; Bendo, George J.; Madden, Suzanne C.; Boselli, Alessandro; Cooray, Asantha; Page, Mathew J.

    2012-10-20

    The first complete submillimeter spectrum (190-670 {mu}m) of the Seyfert 2 galaxy NGC 1068 has been observed with the SPIRE Fourier transform spectrometer on board the Herschel Space Observatory. The sequence of CO lines (J {sub up} = 4-13), lines from H{sub 2}O, the fundamental rotational transition of hydrogen fluoride, two o-H{sub 2}O{sup +} lines, and one line each from CH{sup +} and OH{sup +} have been detected, together with the two [C I] lines and the [N II] 205 {mu}m line. The observations in both single pointing mode with sparse image sampling and in mapping mode with full image sampling allow us to disentangle two molecular emission components, one due to the compact circumnuclear disk (CND) and one from the extended region encompassing the star-forming ring (SF-ring). Radiative transfer models show that the two CO components are characterized by densities of n(H{sub 2}) = 10{sup 4.5} and 10{sup 2.9} cm{sup -3} and temperatures of T {sub kin} = 100 K and 127 K, respectively. A comparison of the CO line intensities with the photodissociation region (PDR) and X-ray-dominated region (XDR) models, together with the other observational constraints, such as the observed CO surface brightness and the radiation field, indicates that the best explanation for the CO excitation of the CND is an XDR with a density of n(H{sub 2}) {approx} 10{sup 4} cm{sup -3} and an X-ray flux of 9 erg s{sup -1} cm{sup -2}, consistent with illumination by the active galactic nucleus, while the CO lines in the SF-ring are better modeled by a PDR. The detected water transitions, together with those observed with the Herschel PACS spectrometer, can be modeled by a large velocity gradient model with low temperature (T {sub kin} {approx} 40 K) and high density (n(H{sub 2}) in the range 10{sup 6.7}-10{sup 7.9} cm{sup -3}). The emission of H{sub 2}O{sup +} and OH{sup +} are in agreement with PDR models with cosmic-ray ionization. The diffuse ionized atomic component observed through the [N

  11. The continuum and narrow-line region of the narrow-line Seyfert 1 galaxy Mrk 766

    NASA Astrophysics Data System (ADS)

    Rodríguez-Ardila, A.; Contini, M.; Viegas, S. M.

    2005-02-01

    We present the first spectroscopic observations in the interval 0.8-4.0 μm, complemented with existing Hubble Space Telescope ultraviolet (UV) and optical spectroscopy, of the narrow-line Seyfert 1 galaxy Mrk 766. The near-infrared spectrum is characterized by numerous permitted lines of HI, HeI, HeII and FeII, and forbidden lines of [SII], [SIII] and [FeII] among others. Highly ionized species such as [SiIX], [SiX], [SIX] and [MgVII] are also observed. The continuum emission has a complex shape, with contributions from the central engine, circumnuclear stellar population and dust. This last component is demonstrated by the presence of an excess of emission peaking at 2.25 μm, well fitted by a blackbody function with Tbb= 1200 K. That temperature is close to the evaporation temperature of graphite grains. As such, it provides strong evidence of hot dust, probably very close to the nucleus. Consistent modelling of the line spectrum and the broad-band continuum by composite models, which account for the photoionizing flux of the central engine and shocks, shows that shock velocities range between 100 and 500 km s-1, the pre-shock densities between 100 and 1000 cm-3 and the radiation fluxes from the active centre between 109 and 5 × 1012 photon cm-2 s-1 eV-1 at 1 Ryd with spectral indices αUV=-1.5 and αX=-0.4. Adopting silicate grains, dust-to-gas ratios are between 10-6 and 4 × 10-4 by mass. The emitting clouds are at an average distance of 160 pc from the centre, with high-velocity clouds closer and low-velocity clouds further from the centre. The N/H relative abundance deduced from the fit of the [NII] 6548+/[OIII] 5007+ line ratio could be twice the solar value. On the other hand, Fe is depleted from the gaseous phase by a factor >2, most probably trapped into grains. Ratios of calculated to observed line ratios to Hβ indicate an average contribution of the broad-line region to the observed Hβ of approximately 40 per cent.

  12. FE K EMISSION AND ABSORPTION FEATURES IN THE XMM-EPIC SPECTRUM OF THE SEYFERT GALAXY IC 4329A

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Reeves, J. N.; Braito, V.

    2001-01-01

    We present a re-analysis of the XMM-Newton long-look of the X-ray bright Seyfert galaxy IC 4329a. The Fe K bandpass is dominated by two peaks, consistent with emission from neutral or near-neutral Fe Ka and KP. A relativistic diskline model whereby both peaks are the result of one doubly-peaked diskline profile is found to be a poor description of the data. Models using two relativistic disklines are found to describe the emission profile well. A low-inclination, moderately-relativistic dual-diskline model is possible if the contribution from narrow components, due to distant material, is small or absent. A high-inclination, moderately relativistic profile for each peak is possible if there are roughly equal contributions from both the broad and narrow components. Upper limits on Fe XXV and Fe XXVI emission and absorption at the systemic velocity of IC 4329a are obtained. We also present the results of RXTE monitoring of this source obtained so far; the combined XMM-Newton and RXTE data sets allow us to explore the time-resolved spectral behavior of this source on time scales ranging from hours to 2 years. We find no strong evidence for variability of the Fe Ka emission line on any time scale probed, likely due to the minimal level of continuum variability. We detect a narrow absorption line, at a energy of 7.68 keV in the rest frame of the source; its significance has been confirmed using Monte Carlo simulations. This feature is most likely due to absorption from Fe XXVI blueshifted to approximately 0.1c relative to the systemic velocity, making IC 4329a the lowest-redshift AGN known with a high-velocity, highly-ionized outflow component. As is often the case with similar outflows seen in high-luminosity quasars, the estimated mass outflow rate is larger than the inflow accretion rate, signaling that the outflow represents a substantial portion of the total energy budget of the AGN. The outflow could arise from a radiatively-driven disk wind, or it may be in the

  13. THE SWIFT BURST ALERT TELESCOPE DETECTED SEYFERT 1 GALAXIES: X-RAY BROADBAND PROPERTIES AND WARM ABSORBERS

    SciTech Connect

    Winter, Lisa M.; Veilleux, Sylvain; McKernan, Barry; Kallman, T. R.

    2012-02-01

    We present results from an analysis of the broadband, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey conducted in the 14-195 keV band. Therefore, our sources are largely unbiased toward both obscuration and host galaxy properties. Our detailed and uniform model fits to Suzaku/BAT and XMM-Newton/BAT spectra include the neutral absorption, direct power-law, reflected emission, soft excess, warm absorption, and narrow Fe I K{alpha} emission properties for the entire sample. We significantly detect O VII and O VIII edges in 52% of our sample. The strength of these detections is strongly correlated with the neutral column density measured in the spectrum. Among the strongest detections, X-ray grating and UV observations, where available, indicate outflowing material. The ionized column densities of sources with O VII and O VIII detections are clustered in a narrow range with N{sub warm} {approx} 10{sup 21} cm{sup -2}, while sources without strong detections have column densities of ionized gas an order of magnitude lower. Therefore, we note that sources without strong detections likely have warm ionized outflows present but at low column densities that are not easily probed with current X-ray observations. Sources with strong complex absorption have a strong soft excess, which may or may not be due to difficulties in modeling the complex spectra of these sources. Still, the detection of a flat {Gamma} {approx} 1 and a strong soft excess may allow us to infer the presence of strong absorption in low signal-to-noise active galactic nucleus spectra. Additionally, we include a useful correction from the Swift BAT luminosity to bolometric luminosity, based on a comparison of our spectral fitting results with published spectral energy distribution fits from 33 of our sources.

  14. Bright galaxies at z=9-11 from pure-parallel HST observations: Building a unique sample for JWST with Spitzer/IRAC

    NASA Astrophysics Data System (ADS)

    Bernard, Stephanie; Trenti, Michele; Bouwens, Rychard

    2016-08-01

    The combination of observations taken by Hubble and Spitzer revealed the unexpected presence of sources as bright as our own Milky Way as early as 400 Myr after the Big Bang, potentially highlighting a new highly efficient regime for star formation in L>L* galaxies at very early times. Yet, the sample of high-quality z>8 galaxies that have both HST and Spitzer/IRAC imaging is still very small, particularly at high luminosities. We propose here to remedy this situation and efficiently follow-up with Spitzer/IRAC the most promising z>8 sources from our Hubble Brightest of Reionizing Galaxies (BoRG) survey, which covers a footprint on the sky similar to CANDELS, provides a deeper search than ground-based surveys like UltraVISTA, and is robust against cosmic variance because of its 180 independent lines of sight. The proposed new 3.6 micron observations will continue the Spitzer cycle 12 BORG911 program and target 15 additional fields, leveraging over 300 new HST orbits (350 sqarcmin) to identify a final sample of about 5 to 10 bright galaxies at z >= 8.5. For optimal time use (just over 22 hours), our goal is to readily discriminate between z>8 sources (undetected or marginally detected in IRAC) and z~2 interlopers (strongly detected in IRAC) with just 1-2 hours per pointing. The high-quality candidates that we will identify with IRAC will be ideal targets for further studies to investigate the reionization state of the inter-galactic medium through near-IR Keck/VLT spectroscopy. They will also be uniquely suited to measurement of the redshift and stellar population properties through JWST/NIRSPEC observations, with the potential to elucidate how the first generations of stars are assembled in the earliest stages of the epoch of reionization.

  15. Spitzer observations of red galaxies: Implication for high-redshift star formation

    NASA Astrophysics Data System (ADS)

    Papovich, Casey

    2006-03-01

    My colleagues and I identified distant red galaxies (DRGs) with J - Ks > 2.3 in the southern Great Observatories Origins Deep Surveys (GOODS-S) field. These galaxies reside at z ˜ 1-3.5, (< z> ≃ 2.2) and based on their ACS (0.4-1 μm), ISAAC (1-2.2 μm), and IRAC (3-8 μm) photometry, they typically have stellar masses M ⩾ 10 11 M⊙. Interestingly, more than 50% of these objects have 24 μm flux densities ⩾50 μJy. Attributing the IR emission to star-formation implies star-formation rates (SFRs) of ≃100-1000 M⊙ yr -1. As a result, galaxies with M ⩾ 10 11 M⊙ have specific SFRs equal to or exceeding the global value at z ˜ 1.5-3. In contrast, galaxies with M ⩾ 10 11 M⊙ at z ˜ 0.3-0.75 have specific SFRs less than the global average, and more than an order of magnitude lower than that for massive DRGs at z ˜ 1.5-3. Thus, the bulk of star formation in massive galaxies is largely complete by z ˜ 1.5. The red colors and large inferred stellar masses in the DRGs suggest that much of the star formation in these galaxies occurred at redshifts z ≳ 5-6. Using model star-formation histories that match the DRG colors and stellar masses at z ˜ 2-3, and measurements of the UV luminosity density at z ≳ 5-6, we consider what constraints exist on the stellar initial mass function in the progenitors of the massive DRGs at z ˜ 2-3.

  16. CaII in Luminous Narrow-line Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Leighly, Karen; Dietrich, M.

    2009-01-01

    FeII emission is an important component of the low-ionization broad-line emission in quasars, comprising up to 1/3 of the total line emission, and performing as a primary coolant. In addition, FeII potentially can be used as a probe of gas metallicity (i.e., preceding stellar evolution). However, FeII is difficult to study because the Fe+ ion yields a complex spectrum of several hundred-thousand emission lines. CaII has been shown to be a valuable surrogate for FeII, with the H&K lines analogous to the UV FeII, and the IR triplet analogous to optical FeII. The advantage of studying CaII compared with FeII is that while the gross atomic structure is similar, the number of lines is dramatically reduced (five versus thousands). CaII H&K (3934, 3968Å) has rarely been identified in emission in quasars and AGN, possibly because the gas is very optically thick and the emission has been converted to the CaII IR triplet (8498, 85442, 8662Å), or because of absorption in the host galaxy. An exception is the luminous narrow-line quasar PHL 1811, and examination of quasars in the SDSS reveals a number of others that show CaII H&K as well, along with other objects that appear otherwise similar but do not have CaII H&K in their spectra. We present preliminary results from observations using SpeX on the IRTF, NASA's 3m telescope on Mauna Kea, to study CaII IR triplet emission in a sample of quasars both with and without CaII H&K. The sample has a range of optical FeII/Hα914 ratios, and the IR CaII triplet/OI (8446Å) ratio follows roughly the same pattern. This behavior is expected if the IR CaII triplet is analogous to optical FeII, and the OI is produced by Bowen fluorescence. A range of CaII H&K/CaII IR triplet ratios is found. Additional results will be presented.

  17. DEEP SPITZER 24 {mu}m COSMOS IMAGING. I. THE EVOLUTION OF LUMINOUS DUSTY GALAXIES-CONFRONTING THE MODELS

    SciTech Connect

    Le Floc'h, Emeric; Ilbert, Olivier; Riguccini, Laurie; Kartaltepe, Jeyhan; Sanders, David; Aussel, Herve; Feruglio, Chiara; Frayer, David T.; Salvato, Mara; Capak, Peter; Scoville, Nick; Arnouts, Stephane; Surace, Jason; Sheth, Kartik; Yan Lin; Rodighiero, Giulia; Heinis, Sebastien; McCracken, Henry Joy; Thompson, David; Koekemoer, Anton

    2009-09-20

    We present the first results obtained from the identification of {approx}30,000 sources in the Spitzer/24 {mu}m observations of the COSMOS field at S{sub 24{mu}m} {approx}> 80 {mu}Jy. Using accurate photometric redshifts ({sigma} {sub z} {approx} 0.12 at z {approx} 2 for 24 {mu}m sources with i {sup +} {approx}< 25 mag AB) and simple extrapolations of the number counts at faint fluxes, we resolve with unprecedented detail the buildup of the mid-infrared background across cosmic ages. We find that {approx}50% and {approx}80% of the 24 {mu}m background intensity originate from galaxies at z {approx}< 1 and z {approx}< 2, respectively, supporting the scenario where highly obscured sources at very high redshifts (z {approx}> 2) contribute only marginally to the cosmic infrared background. Assuming flux-limited selections at optical wavelengths, we also find that the fraction of i {sup +}-band sources with 24 {mu}m detection strongly increases up to z {approx} 2 as a consequence of the rapid evolution that star-forming galaxies have undergone with look-back time. Nonetheless, this rising trend shows a clear break at z {approx} 1.3, probably due to k-correction effects implied by the complexity of spectral energy distributions in the mid-infrared. Finally, we compare our results with the predictions from different models of galaxy formation. We note that semianalytical formalisms currently fail to reproduce the redshift distributions observed at 24 {mu}m. Furthermore, the simulated galaxies at S {sub 24{mu}m} > 80 {mu}Jy exhibit R-K colors much bluer than observed and the predicted K-band fluxes are systematically underestimated at z {approx}> 0.5. Unless these discrepancies mainly result from an incorrect treatment of extinction in the models they may reflect an underestimate of the predicted density of high-redshift massive sources with strong ongoing star formation, which would point to more fundamental processes and/or parameters (e.g., initial mass function

  18. SUZAKU MONITORING OF THE SEYFERT 1 GALAXY NGC 5548: WARM ABSORBER LOCATION AND ITS IMPLICATION FOR COSMIC FEEDBACK

    SciTech Connect

    Krongold, Y.; Andrade-Velazquez, M.; Binette, L.; Jimenez-Bailon, E.; Elvis, M.; Nicastro, F.; Brickhouse, N. S.; Liu, Y.; Wilkes, B.; Mathur, S.; Reeves, J. N.; Grupe, D.; McHardy, I. M.; Minezaki, T.; Yoshii, Y.

    2010-02-10

    We present a 2 month Suzaku X-ray monitoring of the Seyfert 1 galaxy NGC 5548. The campaign consists of seven observations (with exposure time of {approx}30 ks each), separated by {approx}1 week. This paper focus on the X-ray Imaging Spectrometer data of NGC 5548. We analyze the response in the opacity of the gas that forms the well-known ionized absorber in this source for ionizing flux variations. Despite variations by a factor of {approx}4 in the impinging continuum, the soft X-ray spectra of the source show little spectral variations, suggesting no response from the ionized absorber. A detailed time modeling of the spectra confirms the lack of opacity variations for an absorbing component with high ionization (U{sub X} {approx} -0.85), and high outflow velocity (v{sub out} {approx} 1040 km s{sup -1}), as the ionization parameter was found to be consistent with a constant value during the whole campaign. Instead, the models suggest that the ionization parameter of a low ionization (U{sub X} {approx} -2.8), low velocity (v{sub out} {approx} 590 km s{sup -1}) absorbing component might be changing linearly with the ionizing flux, as expected for gas in photoionization equilibrium. However, given the lack of spectral variations among observations, we consider the variations in this component as tentative. Using the lack of variations, we set an upper limit of n{sub e} < 2.0 x 10{sup 7} cm{sup -3} for the electron density of the gas forming the high ionization, high velocity component. This implies a large distance from the continuum source (R>0.033 pc; R>5000R{sub S} ). If the variations in the low ionization, low velocity component are real, they imply n{sub e} >9.8 x 10{sup 4} cm{sup -3} and R < 3 pc. We discuss our results in terms of two different scenarios: a large-scale outflow originating in the inner parts of the accretion disk, or a thermally driven wind originating much farther out. Given the large distance of the wind, the implied mass outflow rate is

  19. The Spitzer Survey of Stellar Structure in Galaxies (S4G): Multi-component Decomposition Strategies and Data Release

    NASA Astrophysics Data System (ADS)

    Salo, Heikki; Laurikainen, Eija; Laine, Jarkko; Comerón, Sebastien; Gadotti, Dimitri A.; Buta, Ron; Sheth, Kartik; Zaritsky, Dennis; Ho, Luis; Knapen, Johan; Athanassoula, E.; Bosma, Albert; Laine, Seppo; Cisternas, Mauricio; Kim, Taehyun; Muñoz-Mateos, Juan Carlos; Regan, Michael; Hinz, Joannah L.; Gil de Paz, Armando; Menendez-Delmestre, Karin; Mizusawa, Trisha; Erroz-Ferrer, Santiago; Meidt, Sharon E.; Querejeta, Miguel

    2015-07-01

    The Spitzer Survey of Stellar Structure in Galaxies (S4G) is a deep 3.6 and 4.5 μm imaging survey of 2352 nearby (<40 Mpc) galaxies. We describe the S4G data analysis pipeline 4, which is dedicated to two-dimensional structural surface brightness decompositions of 3.6 μm images, using GALFIT3.0. Besides automatic 1-component Sérsic fits, and 2-component Sérsic bulge + exponential disk fits, we present human-supervised multi-component decompositions, which include, when judged appropriate, a central point source, bulge, disk, and bar components. Comparison of the fitted parameters indicates that multi-component models are needed to obtain reliable estimates for the bulge Sérsic index and bulge-to-total light ratio (B/T), confirming earlier results. Here, we describe the preparations of input data done for decompositions, give examples of our decomposition strategy, and describe the data products released via IRSA and via our web page (www.oulu.fi/astronomy/S4G_PIPELINE4/MAIN). These products include all the input data and decomposition files in electronic form, making it easy to extend the decompositions to suit specific science purposes. We also provide our IDL-based visualization tools (GALFIDL) developed for displaying/running GALFIT-decompositions, as well as our mask editing procedure (MASK_EDIT) used in data preparation. A detailed analysis of the bulge, disk, and bar parameters derived from multi-component decompositions will be published separately.

  20. The Spitzer Mid-Infrared Survey of the Inner 2 x 1.5 Degrees of the Galaxy

    NASA Astrophysics Data System (ADS)

    Smith, H. A.; Stolovy, S.; Ramirez, S.; Law, C.; Gezari, D.; Arendt, R.; Cotera, A.; Karr, J.; Yusef-Zadeh, F.; Moseley, H.; Sellgren, K.; Smith, R.

    2006-08-01

    We present IRAC observations of the central 2 x 1.5 degrees (280 x 210 pc) of the Galaxy with 1-2" spatial resolution, corresponding to 0.04-0.08 pc. These data represent the highest spatial resolution and sensitivity large-scale map made to date of the GC at mid-infrared wavelengths. The IRAC data provide a census of the optically obscured stellar sources as well as a detailed map of the highly filamentary structure in the interstellar medium, much of which is dominated by PAH emission from small grains in star-forming regions. Dark clouds displaying a large variety of sizes and morphologies are imaged, many of which remain opaque at IRAC wavelengths. Different views of the GC, spanning radio through x-ray wavelengths, provide comparisons we can use to determine which objects are likely to be foreground. We discuss in particular the 10x10 arcminute area around the Sickle, the Pistol star and the Pistol nebula. The Sickle, the ionized edge of a molecular cloud, has previously been observed in thermal radio emission to have a curved appearance with a center of curvature near the Quintuplet star cluster. Our Spitzer observations at 2'' resolution reveal that the Sickle is comprised of a series of finger-like structures. We interpret these to be formed by photoevaporation of the dense molecular material by the intense UV radiation from the hot, massive stars in the Quintuplet cluster.

  1. Spitzer 24micron Observations of Optical/Near-IR Selected Extremely Red Galaxies: Evidence for Assembly of Massive Galaxies at z approximately 1 - 2?

    NASA Technical Reports Server (NTRS)

    Yan, Lin; Choi, Philip I.; Fadda, D.; Marleau, F. R.; Soifer, B. T.; Im, M.; Armus, L.; Frayer, D. T.; Storrie-Lombardi, L. J.; Thompson, D. J.; Teplitz, H. I.; Helou, G.; Appleton, P. N.; Chapman, S.; Fan, F.; Heinrichsen, I.; Lacy, M.; Shupe, D. L; Squires, G. K.; Surace, J.; G., Wilson

    2004-01-01

    We carried out the direct measurement of the fraction of dusty sources in a sample of extremely red galaxies with (R-K(sub s)) greater than or equal to 5.3 mag and K(sub s) less than 20.2 mag, using from the Spitzer Space Telescope. Combining deep 24 micrometers, K(sub s)- and R-band data over an area of approximately 64 sq.arcmin in the ELAIS N1 field of the Spitzer First Look Survey (FLS), we find that 50 +/- 60% of our ERO sample have measurable 24 micrometer flux above the 3(sigma) flux limit of 40 microns Jy. This flux limit corresponds to a SFR of 12 solar mass/yr at z approximately 1, much mo previous long wavelength measurement. The 24fJ,m-detected EROs have 24-to2.2 and 24-to-0.7micrometr flux ratios consistent with infrared luminous, dusty sources at z approx. 1, and an order of magnitude too red to be explained by an infrared quiescent spiral or a pure old stellar population at any redshift. Some of these 24 micrometer-detected EROs could be AGN, however, the fraction among the whole ERO sample is probably small, 10-20%, as suggested by deep X-ray observations as well as optical spectroscopy. Keck optical spectroscopy of a sample of similarly selected EROs in the FLS field suggests that most of the EROs in ELAIS Nl are probably at z approx. 1.

  2. MODELING DUST AND STARLIGHT IN GALAXIES OBSERVED BY SPITZER AND HERSCHEL: NGC 628 AND NGC 6946

    SciTech Connect

    Aniano, G.; Draine, B. T.; Calzetti, D.; Crocker, A.; Dale, D. A.; Engelbracht, C. W.; Gordon, K. D.; Hunt, L. K.; Kennicutt, R. C.; Galametz, M.; Krause, O.; Rix, H.-W.; Sandstrom, K.; Walter, F.; Leroy, A. K.; Roussel, H.; Sauvage, M.; Bolatto, A. D.; Donovan Meyer, J. E-mail: draine@astro.princeton.edu; and others

    2012-09-10

    We characterize the dust in NGC 628 and NGC 6946, two nearby spiral galaxies in the KINGFISH sample. With data from 3.6 {mu}m to 500 {mu}m, dust models are strongly constrained. Using the Draine and Li dust model (amorphous silicate and carbonaceous grains), for each pixel in each galaxy we estimate (1) dust mass surface density, (2) dust mass fraction contributed by polycyclic aromatic hydrocarbons, (3) distribution of starlight intensities heating the dust, (4) total infrared (IR) luminosity emitted by the dust, and (5) IR luminosity originating in regions with high starlight intensity. We obtain maps for the dust properties, which trace the spiral structure of the galaxies. The dust models successfully reproduce the observed global and resolved spectral energy distributions (SEDs). The overall dust/H mass ratio is estimated to be 0.0082 {+-} 0.0017 for NGC 628, and 0.0063 {+-} 0.0009 for NGC 6946, consistent with what is expected for galaxies of near-solar metallicity. Our derived dust masses are larger (by up to a factor of three) than estimates based on single-temperature modified blackbody fits. We show that the SED fits are significantly improved if the starlight intensity distribution includes a (single intensity) 'delta function' component. We find no evidence for significant masses of cold dust (T {approx}< 12 K). Discrepancies between PACS and MIPS photometry in both low and high surface brightness areas result in large uncertainties when the modeling is done at PACS resolutions, in which case SPIRE, MIPS70, and MIPS160 data cannot be used. We recommend against attempting to model dust at the angular resolution of PACS.

  3. Diffuse emission and pathological Seyfert spectra

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.

    1995-01-01

    In this annual ROSAT status report, the diffuse emission and spectra from Seyfert galaxies are examined. Three papers are presented and their contents include the soft x-ray properties and spectra of a binary millisecond pulsar, the PSPC and HRI observations of a Starburst/Seyfert 2 Galaxy, and an analysis of the possibility of x-ray luminous starbursts in the Einstein Medium Sensitivity Survey.

  4. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

    SciTech Connect

    Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; Dalla Bontà, E.; Ciroi, S.

    2013-12-20

    The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n {sub e} ∼ 10{sup 5} cm{sup –3}) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

  5. Einstein Observatory SSS and MPC observations of the complex X-ray spectra of Seyfert galaxies. [Solid State Spectrometer and Monitor Proportional Counter

    NASA Technical Reports Server (NTRS)

    Turner, T. J.; Weaver, K. A.; Mushotzky, R. F.; Holt, S. S.; Madejski, G. M.

    1991-01-01

    The X-ray spectra of 25 Seyfert galaxies measured with the Solid State Spectrometer on the Einstein Observatory have been investigated. This new investigation utilizes simultaneous data from the Monitor Proportional Counter, and automatic correction for systematic effects in the Solid State Spectrometer which were previously handled subjectively. It is found that the best-fit single-power-law indices generally agree with those previously reported, but that soft excesses of some form are inferred for about 48 percent of the sources. One possible explanation of the soft excess emission is a blend of soft X-ray lines, centered around 0.8 keV. The implications of these results for accretion disk models are discussed.

  6. Swift monitoring and Suzaku spectroscopy of the γ-ray detected narrow-line Seyfert 1 galaxy 1H 0323+342

    NASA Astrophysics Data System (ADS)

    Yao, S.; Yuan, W.; Komossa, S.; Grupe, D.; Fuhrmann, L.; Liu, B.

    2016-02-01

    1H 0323+342 is one of the rare γ-ray detected narrow-line Seyfert 1 galaxies (NLS1s), a special subset of active galactic nuclei (AGN) owing to their hybrid behavior of both NLS1s and blazars. The rarity of such kind of sources makes their properties far from being understood. We analyze simultaneous X-ray and UV/optical monitoring observations of 1H 0323+342 performed by Swift over ~7 years. The UV/X-ray correlation and the broad band SED reveal that the X-ray band is dominated by the disk/corona emission during the observations. The large normalized excess variance of the X-ray variability detected with Suzaku suggests a relatively small black hole mass of the order of 107 M ⊙, consistent with the estimation based on the broad Hβ line in the optical band.

  7. The Carnegie-Spitzer-IMACS Redshift Survey: How the Universe Shaped Galaxies over the Past 8 Gyr and Why It Wasn't All Finished Before z~2

    NASA Astrophysics Data System (ADS)

    Kelson, Daniel David

    2015-08-01

    While the peak of cosmic star-formation occurs by z~2, hierarchical growth leads to the assembly of galaxy groups at much later times. The galaxies in these groups host a substantial fraction of the stellar mass at z~0. Probing the evolution of galaxies in these environments is therefore imperative for understanding the forces that shaped the distributions of galaxies we see today. The Carnegie-Spitzer-IMACS Spectrophotometric Redshift Survey, with its wide-field (total 15 degs^2) and near-IR selection, is uniquely positioned to trace the combined evolution of galaxies and their environments. The survey targets a flux-limited sample of galaxies selected from Spitzer IRAC 3.6µm imaging of SWIRE fields, in order to efficiently trace the stellar mass growth of average galaxies to z~1.5. Our unique methodology for analyzing low-dispersion spectra from IMACS, combined with panchromatic photometry from the ultraviolet to the IR, yielded high quality redshifts, stellar masses, emission line luminosities, and information on recent star-formation. For galaxies up to z~1, the redshift precision is sigma_z/(1+z)<1%, with a spectroscopic completeness sufficient to reliably detect galaxy groups M200 ~ 10^13 Msun. In the Chandra Deep Field South we combine the CSI data with the ultra-deep Chandra and XMM-Newton X-ray observations to make the first statistical measurements of the stellar mass-halo mass relation of low-mass X-ray groups at 0.5galaxy groups can account for the evolution in the quiescent galaxy fraction over time is being directly measured by CSI. We conclude with a preliminary analysis of the

  8. MID-INFRARED PROPERTIES OF NEARBY LUMINOUS INFRARED GALAXIES. I. SPITZER INFRARED SPECTROGRAPH SPECTRA FOR THE GOALS SAMPLE

    SciTech Connect

    Stierwalt, S.; Armus, L.; Surace, J. A.; Inami, H.; Petric, A. O.; Diaz-Santos, T.; Haan, S.; Howell, J.; Marshall, J.; Charmandaris, V.; Kim, D. C.; Mazzarella, J. M.; Chan, B.; Spoon, H. W. W.; Veilleux, S.; Evans, A.; Sanders, D. B.; Appleton, P.; Bothun, G.; Bridge, C. R.; and others

    2013-05-01

    The Great Observatories All-Sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here we present low resolution Spitzer Infrared Spectrograph spectra covering 5-38 {mu}m and provide a basic analysis of the mid-IR spectral properties observed for nearby LIRGs. In a companion paper, we discuss detailed fits to the spectra and compare the LIRGs to other classes of galaxies. The GOALS sample of 244 nuclei in 180 luminous (10{sup 11} {<=} L {sub IR}/L {sub Sun} < 10{sup 12}) and 22 ultraluminous (L {sub IR}/L {sub Sun} {>=} 10{sup 12}) IR galaxies represents a complete subset of the IRAS Revised Bright Galaxy Sample and covers a range of merger stages, morphologies, and spectral types. The majority (>60%) of the GOALS LIRGs have high 6.2 {mu}m polycyclic aromatic hydrocarbon (PAH) equivalent widths (EQW{sub 6.2{mu}m} > 0.4 {mu}m) and low levels of silicate absorption (s {sub 9.7{mu}m} > -1.0). There is a general trend among the U/LIRGs for both silicate depth and mid-infrared (MIR) slope to increase with increasing L {sub IR}. U/LIRGs in the late to final stages of a merger also have, on average, steeper MIR slopes and higher levels of dust obscuration. Together, these trends suggest that as gas and dust is funneled toward the center of a coalescing merger, the nuclei become more compact and more obscured. As a result, the dust temperature increases also leading to a steeper MIR slope. The sources that depart from these correlations have very low PAH equivalent width (EQW{sub 6.2{mu}m} < 0.1 {mu}m) consistent with their emission being dominated by an active galactic nucleus (AGN) in the MIR. These extremely low PAH EQW sources separate into two distinct types: relatively unobscured sources with a very hot dust component (and thus very shallow MIR slopes) and heavily dust obscured nuclei with a steep temperature gradient. The most heavily dust obscured sources are also the most compact in their MIR

  9. Structure of the Circumnuclear Region of Seyfert 2 Galaxies Revealed by Rossi X-Ray Timing Explorer Hard X-Ray Observations of NGC 4945.

    PubMed

    Madejski; Zycki; Done; Valinia; Blanco; Rothschild; Turek

    2000-06-01

    NGC 4945 is one of the brightest Seyfert galaxies on the sky at 100 keV, but is completely absorbed below 10 keV; its absorption column is probably the largest that still allows a direct view of the nucleus at hard X-ray energies. Our observations of it with the Rossi X-Ray Timing Explorer (RXTE) satellite confirm the large absorption, which for a simple phenomenological fit using an absorber with solar abundances implies a column of 4.5+0.4-0.4x1024 cm(-2). Using a more realistic scenario (requiring Monte Carlo modeling of the scattering), we infer the optical depth to Thomson scattering of approximately 2.4. If such a scattering medium were to subtend a large solid angle from the nucleus, it should smear out any intrinsic hard X-ray variability on timescales shorter than the light-travel time through it. The rapid (with a timescale of approximately 1 day) hard X-ray variability of NGC 4945 discovered by us with RXTE implies that the bulk of the extreme absorption in this object does not originate in a parsec-size, geometrically thick molecular torus. Instead, the optically thick material on parsec scales must be rather geometrically thin, subtending a half-angle less than 10 degrees, and it is likely to be the same disk of material that is responsible for the water maser emission observed in NGC 4945. Local number counts of Seyfert 1 and Seyfert 2 galaxies show a large population of heavily obscured active galactic nuclei (AGNs) which are proposed to make up the cosmic X-ray background (CXRB). However, for this to be the case, the absorption geometry in the context of axially symmetric unification schemes must have the obscuring material subtending a large scale height-contrary to our inferences about NGC 4945-implying that NGC 4945 is not a prototype of obscured AGNs postulated to make up the CXRB. The small solid angle of the absorber, together with the black hole mass (of approximately 1.4x106 M( middle dot in circle)) from megamaser measurements, allows a

  10. A low-luminosity type-1 QSO sample . IV. Molecular gas contents and conditions of star formation in three nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Moser, Lydia; Krips, Melanie; Busch, Gerold; Scharwächter, Julia; König, Sabine; Eckart, Andreas; Smajić, Semir; García-Marin, Macarena; Valencia-S., Mónica; Fischer, Sebastian; Dierkes, Jens

    2016-03-01

    We present a pilot study of ~3'' resolution observations of low CO transitions with the Submillimeter Array in three nearby Seyfert galaxies, which are part of the low-luminosity quasi-stellar object (LLQSOs) sample consisting of 99 nearby (z = 0.06) type-1 active galactic nuclei (AGN) taken from the Hamburg/ESO quasi-stellar object (QSO) survey. Two sources were observed in 12CO(2-1) and 13CO(2-1) and the third in 12CO(3-2) and HCO+(4-3). None of the sources is detected in continuum emission. More than 80% of the 12CO detected molecular gas is concentrated within a diameter (FWHM) < 1.8 kpc. 13CO is tentatively detected, while HCO+ emission could not be detected. All three objects show indications of a kinematically decoupled central unresolved molecular gas component. The molecular gas masses of the three galaxies are in the range Mmol = (0.7-8.7) × 109M⊙. We give lower limits for the dynamical masses of Mdyn> 1.5 × 109M⊙ and for the dust masses of Mdust> 1.6 × 106M⊙. The R21 = 12CO/13CO(2-1) line luminosity ratios show Galactic values of R21 ~ 5-7 in the outskirts and R21 ≳ 20 in the central region, similar to starbursts and (ultra)luminous infrared galaxies ((U)LIRGs; i.e. LIRGs and ULIRGs), implying higher temperatures and stronger turbulence. All three sources show indications of 12CO(2-1)/12CO(1-0) ratios of ~0.5, suggesting a cold or diffuse gas phase. Strikingly, the 12CO(3-2)/(1-0) ratio of ~1 also indicates a higher excited phase. Since these galaxies have high infrared luminosities of LIR ≥ 1011L⊙ and seem to contain a circumnuclear starburst with minimum surface densities of gas and star formation rate (SFR) around Σmol = 50-550 M⊙pc-2 and ΣSFR = 1.1-3.1 M⊙ kpc-2 yr-1, we conclude that the interstellar medium in the centers of these LIRG Seyferts is strongly affected by violent star formation and better described by the ULIRG mass conversion factor.

  11. VizieR Online Data Catalog: Spitzer photometry of globulars in 2 galaxies (Spitler+, 2008)

    NASA Astrophysics Data System (ADS)

    Spitler, L. R.; Forbes, D. A.; Beasley, M. A.

    2010-06-01

    Catalogues are described in Spitler et al. (2008MNRAS.389.1150S) All photometry is corrected for Galactic dust extinction and are on the Vega photometric system. NGC 5128 optical photometry is from Peng et al. (2004ApJS..150..367P), as compiled in Woodley et al. (2007AJ....134..494W). Globular cluster identification numbers are from Woodley et al. (2007, Cat. J/AJ/134/494). NGC 4594 optical photometry is from Spitler et al. (2006AJ....132.1593S) updated with new aperture corrections as described in Harris et al. (2010MNRAS.401.1965H). Identification number, globular cluster half-light radii and the assumed distance modulus for the half-light radii are from Spitler et al. (2006, Cat. J/AJ/132/1593). A ultra-compact dwarf galaxy is included in this catalogue with ID="ucd" (see also Hau et al. 2009MNRAS.394L..97H). (2 data files).

  12. Science Highlights from the Spitzer Survey of Stellar Structure in Galaxies (S4G) & Public Release of S4G Data

    NASA Astrophysics Data System (ADS)

    Sheth, Kartik

    2013-01-01

    The Spitzer Survey of Stellar Structure in Galaxies (S4G) is the largest and the most homogenous survey of the distribution of mass and stellar structure in over 2,300 nearby galaxies. With an integration time of four minutes per pixel at 3.6 and 4.5 microns, the S4G maps are extremely deep, tracing the stellar surface densities of < 1 solar mass per square parsec! S4G is the ultimate survey of the endoskeleton of nearby galaxies from dwarfs to ellipticals and affords an incredible treasury of data which we can address a host of outstanding questions in galaxy evolution. At this special session we will present details on the public release of this survey which will include science ready images, masks for the foreground and background stars, globally integrated properties and radial profiles of all galaxies. In addition we will release the results from a GALFIT decomposition of 200 galaxies which will be supplemented with the remainder of the survey within six months. The data are being released through the NASA/IPAC Infrared Science Archive (IRSA). I will present an overview of the survey, the data we are releasing, introduce the speakers and present science highlights from the team.

  13. Spitzer Spies Spectacular Sombrero

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2 NASA's Spitzer Space Telescope set its infrared eyes on one of the most famous objects in the sky, Messier 104, also called the Sombrero galaxy. In this striking infrared picture, Spitzer sees an exciting new view of a galaxy that in visible light has been likened to a 'sombrero,' but here looks more like a 'bulls-eye.'

    Recent observations using Spitzer's infrared array camera uncovered the bright, smooth ring of dust circling the galaxy, seen in red. In visible light, because this galaxy is seen nearly edge-on, only the near rim of dust can be clearly seen in silhouette. Spitzer's full view shows the disk is warped, which is often the result of a gravitational encounter with another galaxy, and clumpy areas spotted in the far edges of the ring indicate young star-forming regions.

    Spitzer's infrared view of the starlight from this galaxy, seen in blue, can pierce through obscuring murky dust that dominates in visible light. As a result, the full extent of the bulge of stars and an otherwise hidden disk of stars within the dust ring are easily seen.

    The Sombrero galaxy is located some 28 million light years away. Viewed from Earth, it is just six degrees south of its equatorial plane. Spitzer detected infrared emission not only from the ring, but from the center of the galaxy too, where there is a huge black hole, believed to be a billion times more massive than our Sun.

    This picture is composed of four images taken at 3.6 (blue), 4.5 (green), 5.8 (orange), and 8.0 (red) microns. The contribution from starlight (measured at 3.6 microns) has been subtracted from the 5.8 and 8-micron images to enhance the visibility of the dust features.

    In figure 1, the new picture of Messier 104 combines a recent infrared observation from NASA's Spitzer Space Telescope with a well

  14. Variability and Spectral Studies of Luminous Seyfert 1 Galaxy Fairall 9. Search for the Reflection Component is a Quasar: RXTE and ASCA Observation of a Nearby Radio-Quiet Quasar MR 2251-178

    NASA Technical Reports Server (NTRS)

    Leighly, Karen M.

    1999-01-01

    Monitoring observations with interval of 3 days using RXTE (X Ray Timing Explorer) of the luminous Seyfert 1 galaxy Fairall 9 were performed for one year. The purpose of the observations were to study the variability of Fairall 9 and compare the results with those from the radio-loud object 3C 390.3. The data has been received and analysis is underway, using the new background model. An observation of the quasar MR 2251-178 was made in order to determine whether or not it has a reflection component. Older background models gave an unacceptable subtraction and analysis is underway using the new background model. The observation of NGC 6300 showed that the X-ray spectrum from this Seyfert 2 galaxy appears to be dominated by Compton reflection.

  15. DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?

    SciTech Connect

    Tanaka, Masaomi; Morokuma, Tomoki; Doi, Mamoru; Kikuchi, Yuki; Itoh, Ryosuke; Akitaya, Hiroshi; Tanaka, Yasuyuki T.; Kawabata, Koji S.; Tominaga, Nozomu; Saito, Yoshihiko; Kawai, Nobuyuki; Stawarz, Łukasz; Gandhi, Poshak; Ali, Gamal; Essam, Ahmad; Hamed, Gamal; Aoki, Tsutomu; Contreras, Carlos; Hsiao, Eric Y.; Iwata, Ikuru; and others

    2014-10-01

    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of ∼10{sup 7} M {sub ☉} implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ≅ 4 × 10{sup 2}-3 × 10{sup 3}, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and γ-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.

  16. CENSUS OF SELF-OBSCURED MASSIVE STARS IN NEARBY GALAXIES WITH SPITZER: IMPLICATIONS FOR UNDERSTANDING THE PROGENITORS OF SN 2008S-LIKE TRANSIENTS

    SciTech Connect

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S.; Thompson, Todd A.; Beacom, J. F.; Prieto, J. L. E-mail: kstanek@astronomy.ohio-state.ed E-mail: thompson@astronomy.ohio-state.ed E-mail: beacom@mps.ohio-state.ed

    2010-06-01

    A new link in the causal mapping between massive stars and potentially fatal explosive transients opened with the 2008 discovery of the dust-obscured progenitors of the luminous outbursts in NGC 6946 and NGC 300. Here, we carry out a systematic mid-IR photometric search for massive, luminous, and self-obscured stars in four nearby galaxies: M33, NGC 300, M81, and NGC 6946. For detection, we use only the 3.6 {mu}m and 4.5 {mu}m IRAC bands, as these can still be used for multi-epoch Spitzer surveys of nearby galaxies ({approx}<10 Mpc). We combine familiar point-spread function and aperture photometry with an innovative application of image subtraction to catalog the self-obscured massive stars in these galaxies. In particular, we verify that stars analogous to the progenitors of the NGC 6946 (SN 2008S) and NGC 300 transients are truly rare in all four galaxies: their number may be as low as {approx}1 per galaxy at any given moment. This result empirically supports the idea that the dust-enshrouded phase is a very short lived phenomenon in the lives of many massive stars and that these objects constitute a natural extension of the asymptotic giant branch sequence. We also provide mid-IR catalogs of sources in NGC 300, M81, and NGC 6946.

  17. Compact steep-spectrum sources as the parent population of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Berton, M.; Caccianiga, A.; Foschini, L.; Peterson, B. M.; Mathur, S.; Terreran, G.; Ciroi, S.; Congiu, E.; Cracco, V.; Frezzato, M.; La Mura, G.; Rafanelli, P.

    2016-06-01

    Narrow-line Seyfert 1 galaxies (NLS1s) are an interesting subclass of active galactic nuclei (AGN), which tipically does not exhibit any strong radio emission. Seven percent of them, though, are radio-loud and often show a flat radio-spectrum (F-NLS1s). This, along to the detection of γ-ray emission coming from them, is usually interpreted as a sign of a relativistic beamed jet oriented along the line of sight. An important aspect of these AGN that must be understood is the nature of their parent population, in other words how do they appear when observed under different angles. In the recent literature it has been proposed that a specific class of radio-galaxies, compact-steep sources (CSS) classified as high excitation radio galaxies (HERG), can represent the parent population of F-NLS1s. To test this hypothesis in a quantitative way,in this paper we analyzed the only two statistically complete samples of CSS/HERGs and F-NLS1s available in the literature. We derived the black hole mass and Eddington ratio distributions, and we built for the first time the radio luminosity function of F-NLS1s. Finally, we applied a relativistic beaming model to the luminosity function of CSS/HERGs, and compared the result with the observed function of F-NLS1s. We found that compact steep-spectrum sources are valid parent candidates and that F-NLS1s, when observed with a different inclination, might actually appear as CSS/HERGs.

  18. Spitzer UltRa Faint SUrvey Program (SURFS UP). II. IRAC-detected Lyman-Break Galaxies at 6 ≲ z ≲ 10 behind Strong-lensing Clusters

    NASA Astrophysics Data System (ADS)

    Huang, Kuang-Han; Bradač, Maruša; Lemaux, Brian C.; Ryan, R. E., Jr.; Hoag, Austin; Castellano, Marco; Amorín, Ricardo; Fontana, Adriano; Brammer, Gabriel B.; Cain, Benjamin; Lubin, L. M.; Merlin, Emiliano; Schmidt, Kasper B.; Schrabback, Tim; Treu, Tommaso; Gonzalez, Anthony H.; von der Linden, Anja; Knight, Robert I.

    2016-01-01

    We study the stellar population properties of the IRAC-detected 6 ≲ z ≲ 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 ≲ z ≲ 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios ≥ 3 in at least one of the IRAC 3.6 and 4.5 μm channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ˜1.2-5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M1600 are between -21.2 and -18.9 mag, while their intrinsic stellar masses are between 2 × 108M⊙ and 2.9 × 109M⊙. We identify two Lyα emitters in our sample from the Keck DEIMOS spectra, one at zLyα = 6.76 (in RXJ 1347) and one at zLyα = 6.32 (in MACS 0454). We find that 4 out of 17 z ≳ 6 galaxy candidates are favored by z ≲ 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]-[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.

  19. Spitzer Spies Spectacular Sombrero

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2 NASA's Spitzer Space Telescope set its infrared eyes on one of the most famous objects in the sky, Messier 104, also called the Sombrero galaxy. In this striking infrared picture, Spitzer sees an exciting new view of a galaxy that in visible light has been likened to a 'sombrero,' but here looks more like a 'bulls-eye.'

    Recent observations using Spitzer's infrared array camera uncovered the bright, smooth ring of dust circling the galaxy, seen in red. In visible light, because this galaxy is seen nearly edge-on, only the near rim of dust can be clearly seen in silhouette. Spitzer's full view shows the disk is warped, which is often the result of a gravitational encounter with another galaxy, and clumpy areas spotted in the far edges of the ring indicate young star-forming regions.

    Spitzer's infrared view of the starlight from this galaxy, seen in blue, can pierce through obscuring murky dust that dominates in visible light. As a result, the full extent of the bulge of stars and an otherwise hidden disk of stars within the dust ring are easily seen.

    The Sombrero galaxy is located some 28 million light years away. Viewed from Earth, it is just six degrees south of its equatorial plane. Spitzer detected infrared emission not only from the ring, but from the center of the galaxy too, where there is a huge black hole, believed to be a billion times more massive than our Sun.

    This picture is composed of four images taken at 3.6 (blue), 4.5 (green), 5.8 (orange), and 8.0 (red) microns. The contribution from starlight (measured at 3.6 microns) has been subtracted from the 5.8 and 8-micron images to enhance the visibility of the dust features.

    In figure 1, the new picture of Messier 104 combines a recent infrared observation from NASA's Spitzer Space Telescope with a well

  20. The dusty heart of nearby active galaxies. I. High-spatial resolution mid-IR spectro-photometry of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Hönig, S. F.; Kishimoto, M.; Gandhi, P.; Smette, A.; Asmus, D.; Duschl, W.; Polletta, M.; Weigelt, G.

    2010-06-01

    In a series of papers, we aim at stepping towards characterizing physical properties of the AGN dust torus by combining IR high-spatial resolution observations with 3D clumpy torus models. In this first paper, we present mid-IR imaging and 8-13 μm low-resolution spectroscopy of nine type 1 and ten type 2 AGN. The observations were carried out with the VLT/VISIR mid-IR imager and spectrograph and can be considered the largest currently available mid-infrared spectro-photometric data set of AGN at spatial resolution ⪉100 pc. These data resolve scales at which the emission from the dust torus dominates the overall flux, and emission from the host galaxy (e.g. star-formation) is resolved out in most cases. The silicate absorption features are moderately deep and emission features, if seen at all, are shallow. The strongest silicate emission feature in our sample shows some notable shift of the central wavelength from the expected 9.7 μm (based on ISM extinction curves) to ~10.5 μm. We compare the observed mid-IR luminosities of our objects to AGN luminosity tracers (X-ray, optical and [O iii] luminosities) and find that the mid-IR radiation is emitted quite isotropically. In two cases, IC 5063 and MCG-3-34-64, we find evidence for extended dust emission in the narrow-line region. We confirm the correlation between observed silicate feature strength and Hydrogen column density, which was recently found in Spitzer data at lower spatial resolution. In a further step, our 3D clumpy torus model has been used to interpret the data. We show that the strength of the silicate feature and the mid-IR spectral index α can be used to get reasonable constraints on the radial dust distribution of the torus and the average number of clouds N0 along an equatorial line-of-sight in clumpy torus models. The mid-IR spectral index α is almost exclusively determined by the radial dust distribution power-law index a, while the silicate feature depth mostly depends on N0 and the torus

  1. Simultaneous NuSTAR and XMM-Newton 0.5-80 KeV Spectroscopy of the Narrow-Line Seyfert 1 Galaxy SWIFT J2127.4+5654

    NASA Technical Reports Server (NTRS)

    Marinucci, A.; Matt, G.; Kara, E.; Miniutti, G.; Elvis, M.; Arevalo, P.; Ballantyne, D. R.; Balokovic, M.; Bauer, F.; Brenneman, L.; Boggs, S. E.; Cappi, M.; Christensen, F. E.; Craig, W. W.; Fabian, A. C.; Fuerst, F.; Hailey, C. J.; Harrison, F. A.; Risaliti, G.; Reynolds, C. S.; Stern, D. K.; Walton, D. J.; Zhang, W.

    2014-01-01

    We present a broad-band spectral analysis of the joint XMM-Newton and Nuclear Spectroscopic Telescope Array observational campaign of the narrow-line Seyfert 1 SWIFT J2127.4+5654, consisting of 300 kiloseconds performed during three XMM-Newton orbits. We detect a relativistic broadened iron K-alpha line originating from the innermost regions of the accretion disc surrounding the central black hole, from which we infer an intermediate spin of a = 0.58 (sup +0.11) (sub -0.17). The intrinsic spectrum is steep (gamma = 2.08 plus or minus 0.01) as commonly found in narrow-line Seyfert 1 galaxies, while the cutoff energy (E (sub c) = 108 (sup +11) (sub -10) kiloelectronvolts) falls within the range observed in broad-line Seyfert 1 galaxies. We measure a low-frequency lag that increases steadily with energy, while at high frequencies, there is a clear lag following the shape of the broad Fe K emission line. Interestingly, the observed Fe K lag in SWIFT J2127.4+5654 is not as broad as in other sources that have maximally spinning black holes. The lag amplitude suggests a continuum-to-reprocessor distance of about 10-20 radius of gyration. These timing results independently support an intermediate black hole spin and a compact corona.

  2. THE MASS PROFILE AND SHAPE OF BARS IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G): SEARCH FOR AN AGE INDICATOR FOR BARS

    SciTech Connect

    Kim, Taehyun; Lee, Myung Gyoon; Sheth, Kartik; Muñoz-Mateos, Juan-Carlos; Zaritsky, Dennis; Elmegreen, Bruce G.; Athanassoula, E.; Bosma, Albert; Holwerda, Benne; Ho, Luis C.; Comerón, Sébastien; Laurikainen, Eija; Salo, Heikki; Knapen, Johan H.; Erroz-Ferrer, Santiago; Hinz, Joannah L.; Buta, Ronald J.; Kim, Minjin; Madore, Barry F.; and others

    2015-01-20

    We have measured the radial light profiles and global shapes of bars using two-dimensional 3.6 μm image decompositions for 144 face-on barred galaxies from the Spitzer Survey of Stellar Structure in Galaxies. The bar surface brightness profile is correlated with the stellar mass and bulge-to-total (B/T) ratio of their host galaxies. Bars in massive and bulge-dominated galaxies (B/T > 0.2) show a flat profile, while bars in less massive, disk-dominated galaxies (B/T ∼ 0) show an exponential, disk-like profile with a wider spread in the radial profile than in the bulge-dominated galaxies. The global two-dimensional shapes of bars, however, are rectangular/boxy, independent of the bulge or disk properties. We speculate that because bars are formed out of disks, bars initially have an exponential (disk-like) profile that evolves over time, trapping more disk stars to boxy bar orbits. This leads bars to become stronger and have flatter profiles. The narrow spread of bar radial profiles in more massive disks suggests that these bars formed earlier (z > 1), while the disk-like profiles and a larger spread in the radial profile in less massive systems imply a later and more gradual evolution, consistent with the cosmological evolution of bars inferred from observational studies. Therefore, we expect that the flatness of the bar profile can be used as a dynamical age indicator of the bar to measure the time elapsed since the bar formation. We argue that cosmic gas accretion is required to explain our results on bar profile and the presence of gas within the bar region.

  3. The symbiosis of variable absorption and blurred reflection in the X-ray-absorbed Seyfert 1.5 galaxy NGC 4151

    NASA Astrophysics Data System (ADS)

    Beuchert, T.; Markowitz, A.; Dauser, T.; García, J.; Keck, M.; Brenneman, L.; Zdziarski, A.; Wilms, J.; Kadler, M.

    2016-06-01

    We present results on time resolved spectroscopy of the Seyfert 1.5 galaxy NGC 4151. Suzaku, NuSTAR and XMM-Newton observations from mid 2011 until the end of 2012 reveal significant variability in absorption by intermediately ionized gas on various time-scales. The soft X-rays, on the other hand, stay rather constant, favoring emission from large-scale, diffuse gas. The soft emission lines are consistent with high resolution spectroscopic studies of the extended emission resolved with Chandra gratings. We extend on recent work by Keck et al., who modeled relativistically blurred, reflected disk emission in a 150 ks Suzaku/NuSTAR observation from 2012. They explored multiple emitting/reflecting components in the context of the "lamppost" geometry. We perform additional testing of blurred disk reflection in NGC 4151, using Suzaku and XMM-Newton observations. We use the latest version of RELXILL, which incorporates a fully angle-resolved treatment of ionized reflection in combination with a thermal Comptonization continuum.

  4. The Seyfert 2 Galaxy NGC 2110: Hard X-Ray Emission Observed by NuStar and Variability of the Iron K-Alpha Line

    NASA Technical Reports Server (NTRS)

    Marinucci, A.; Matt, G.; Bianchi, S.; Lu, T. N.; Arevalo, P.; Balokovic, M.; Ballantyne, D.; Bauer, F. E.; Boggs, S. E.; Stern, D.; Zhang, William W.

    2014-01-01

    We present NuSTAR observations of the bright Seyfert 2 galaxy NGC 2110 obtained in 2012, when the source was at the highest flux level ever observed, and in 2013, when the source was at a more typical flux level. We include archival observations from other X-ray satellites, namely XMM-Newton, Suzaku, BeppoSAX, Chandra and Swift. Simultaneous NuSTAR and Swift broad band spectra (in the 3-80 keV range) indicate a cutoff energy E(sub c) greater than 210 keV, with no detectable contribution from Compton reflection. NGC 2110 is one of the very few sources where no evidence for distant Compton thick scattering is found and, by using temporal information collected over more than a decade, we investigate variations of the iron K(alpha) line on time scales of years. The Fe K alpha line is likely the sum of two components: one constant (originating from distant Compton-thick material) and the other one variable and linearly correlated with the source flux (possibly arising from Compton-thin material much closer to the black hole).

  5. Space Telescope and Optical Reverberation Mapping Project.I. Ultraviolet Observations of the Seyfert 1 Galaxy NGC 5548 with the Cosmic Origins Spectrograph on Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    De Rosa, G.; Peterson, B. M.; Ely, J.; Kriss, G. A.; Crenshaw, D. M.; Horne, Keith; Korista, K. T.; Netzer, H.; Pogge, R. W.; Arévalo, P.; Barth, A. J.; Bentz, M. C.; Brandt, W. N.; Breeveld, A. A.; Brewer, B. J.; Dalla Bontà, E.; De Lorenzo-Cáceres, A.; Denney, K. D.; Dietrich, M.; Edelson, R.; Evans, P. A.; Fausnaugh, M. M.; Gehrels, N.; Gelbord, J. M.; Goad, M. R.; Grier, C. J.; Grupe, D.; Hall, P. B.; Kaastra, J.; Kelly, B. C.; Kennea, J. A.; Kochanek, C. S.; Lira, P.; Mathur, S.; McHardy, I. M.; Nousek, J. A.; Pancoast, A.; Papadakis, I.; Pei, L.; Schimoia, J. S.; Siegel, M.; Starkey, D.; Treu, T.; Uttley, P.; Vaughan, S.; Vestergaard, M.; Villforth, C.; Yan, H.; Young, S.; Zu, Y.

    2015-06-01

    We describe the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Significant correlated variability is found in the continuum and broad emission lines, with amplitudes ranging from ˜30% to a factor of two in the emission lines and a factor of three in the continuum. The variations of all the strong emission lines lag behind those of the continuum, with He ii λ 1640 lagging behind the continuum by ˜2.5 days and Lyα λ 1215, C iv λ 1550, and Si iv λ 1400 lagging by ˜5-6 days. The relationship between the continuum and emission lines is complex. In particular, during the second half of the campaign, all emission-line lags increased by a factor of 1.3-2 and differences appear in the detailed structure of the continuum and emission-line light curves. Velocity-resolved cross-correlation analysis shows coherent structure in lag versus line of sight velocity for the emission lines; the high-velocity wings of C iv respond to continuum variations more rapidly than the line core, probably indicating higher velocity broad-line region clouds at smaller distances from the central engine. The velocity-dependent response of Lyα, however, is more complex and will require further analysis.

  6. VERY LONG BASELINE ARRAY IMAGING OF PARSEC-SCALE RADIO EMISSIONS IN NEARBY RADIO-QUIET NARROW-LINE SEYFERT 1 GALAXIES

    SciTech Connect

    Doi, Akihiro; Asada, Keiichi; Inoue, Makoto; Fujisawa, Kenta; Nagai, Hiroshi; Hagiwara, Yoshiaki; Wajima, Kiyoaki

    2013-03-01

    We conducted Very Long Baseline Array (VLBA) observations of seven nearby narrow-line Seyfert 1 (NLS1) galaxies at 1.7 GHz ({lambda}18 cm) with milliarcsecond resolution. This is the first systematic very long baseline interferometry study focusing on the central parsec-scale regions of radio-quiet NLS1s. Five of the seven were detected at a brightness temperature of {approx}> 5 Multiplication-Sign 10{sup 6} K and contain radio cores with high brightness temperatures of >6 Multiplication-Sign 10{sup 7} K, indicating a nonthermal process driven by jet-producing central engines as in radio-loud NLS1s and other active galactic nucleus classes. VLBA images of MRK 1239, MRK 705, and MRK 766 exhibit parsec-scale jets with clear linear structures. A large portion of the radio power comes from diffuse emission components that are distributed within the nuclear regions ({approx}< 300 pc), which is a common characteristic throughout the observed NLS1s. Jet kinetic powers limited by the Eddington limit may be insufficient to allow the jets to escape to kiloparsec scales for these radio-quiet NLS1s with low-mass black holes of {approx}< 10{sup 7} M {sub Sun }.

  7. Seyfert galaxy ultraviolet emission-line intensities and variability - A self-consistent photoionization analysis applied to broad-line-emitting gas in NGC 3783

    NASA Technical Reports Server (NTRS)

    Koratkar, Anuradha P.; Macalpine, Gordon M.

    1992-01-01

    Well-constrained photoionization models for the Seyfert I galaxy NGC 3783 are developed. Both cross-correlation analyses and line variability trends with varying ionizing radiation flux require a multicomponent picture. All the data for He II 1640 A, C IV 1549 A, and semiforbidden C III 1909 A can be reasonably well reproduced by two cloud components. One has a source-cloud distance of 24 lt-days, gas density around 3 x 10 exp 10/cu cm, ionization parameter range of 0.04-0.2, and cloud thickness such that about half of the carbon is doubly ionized and about half is triply ionized. The other component is located approximately 96 lt-days from the source, is shielded from the source by the inner cloud, has a density about 3 x 10 to the 9th/cu cm, and is characterized by an ionization parameter range of 0.001-0.03, The cloud thickness is such that about 45 percent carbon is doubly ionized and about 55 percent is singly ionized.

  8. The SAURON project - XX. The Spitzer [3.6] - [4.5] colour in early-type galaxies: colours, colour gradients and inverted scaling relations

    NASA Astrophysics Data System (ADS)

    Peletier, Reynier F.; Kutdemir, Elif; van der Wolk, Guido; Falcón-Barroso, Jesús; Bacon, Roland; Bureau, Martin; Cappellari, Michele; Davies, Roger L.; de Zeeuw, P. Tim; Emsellem, Eric; Krajnović, Davor; Kuntschner, Harald; McDermid, Richard M.; Sarzi, Marc; Scott, Nicholas; Shapiro, Kristen L.; van den Bosch, Remco C. E.; van de Ven, Glenn

    2012-01-01

    We investigate the [3.6]-[4.5] Spitzer-IRAC colour behaviour of the early-type galaxies of the SAURON survey, a representative sample of 48 nearby ellipticals and lenticulars. We investigate how this colour, which is unaffected by dust extinction, can be used to constrain the stellar populations in these galaxies. We find a tight relation between the [3.6]-[4.5] colour and effective velocity dispersion, a good mass indicator in early-type galaxies: ([3.6]-[4.5])e = (-0.109 ? 0.007)?+ (0.154 ? 0.016). Contrary to other colours in the optical and near-infrared, we find that the colours become bluer for larger galaxies. The relations are tighter when using the colour inside re (scatter 0.013 mag), rather than the much smaller re/8 aperture (scatter 0.023 mag), due to the presence of young populations in the central regions. We also obtain strong correlations between the [3.6]-[4.5] colour and three strong absorption lines (H?, Mgb and Fe 5015). Comparing our data with the models of Marigo et al., which show that more metal rich galaxies are bluer, we can explain our results in a way consistent with results from the optical, by stating that larger galaxies are more metal rich. The blueing is caused by a strong CO absorption band, whose line strength increases strongly with decreasing temperature and which covers a considerable fraction of the 4.5-?m filter. In galaxies that contain a compact radio source, the [3.6]-[4.5] colour is generally slightly redder (by 0.015 ? 0.007 mag using the re/8 aperture) than in the other galaxies, indicating small amounts of either hot dust, non-thermal emission, or young stars near the centre. We find that the large majority of the galaxies show redder colours with increasing radius. Removing the regions with evidence for young stellar populations (from the H? absorption line) and interpreting the colour gradients as metallicity gradients, we find that our galaxies are more metal poor going outwards. The radial [3.6]-[4.5] gradients

  9. Accretion disc-corona and jet emission from the radio-loud Narrow Line Seyfert 1 galaxy RXJ1633.3+4719

    NASA Astrophysics Data System (ADS)

    Mallick, Labani; Dewangan, G. C.; Gandhi, P.; Misra, R.; Kembhavi, A. K.

    2016-05-01

    We perform X-ray/UV spectral and X-ray variability studies of the radio-loud Narrow Line Seyfert 1 (NLS1) galaxy RXJ1633.3+4719 using XMM-Newton and Suzaku observations from 2011 and 2012. The 0.3-10 keV spectra consist of an ultra-soft component described by an accretion disc blackbody (kT_in = 39.6^{+11.2}_{-5.5} eV) and a power-law due to the thermal Comptonization (Γ =1.96^{+0.24}_{-0.31}) of the disc emission. The disc temperature inferred from the soft excess is at least a factor of two lower than that found for the canonical soft excess emission from radio-quiet NLS1s. The UV spectrum is described by a power-law with photon index 3.05^{+0.56}_{-0.33}. The observed UV emission is too strong to arise from the accretion disc or the host galaxy, but can be attributed to a jet. The X-ray emission from RXJ1633.3+4719 is variable with fractional variability amplitude Fvar=13.5±1.0%. In contrast to radio-quiet AGN, X-ray emission from the source becomes harder with increasing flux. The fractional RMS variability increases with energy and the RMS spectrum is well described by a constant disc component and a variable power-law continuum with the normalization and photon index being anti-correlated. Such spectral variability cannot be caused by variations in the absorption and must be intrinsic to the hot corona. Our finding of possible evidence for emission from the inner accretion disc, jet and hot corona from RXJ1633.3+4719 in the optical to X-ray bands makes this object an ideal target to probe the disc-jet connection in AGN.

  10. Accretion disc-corona and jet emission from the radio-loud narrow-line Seyfert 1 galaxy RX J1633.3+4719

    NASA Astrophysics Data System (ADS)

    Mallick, Labani; Dewangan, G. C.; Gandhi, P.; Misra, R.; Kembhavi, A. K.

    2016-08-01

    We perform X-ray/ultraviolet (UV) spectral and X-ray variability studies of the radio-loud narrow-line Seyfert 1 (NLS1) galaxy RX J1633.3+4719 using XMM-Newton and Suzaku observations from 2011 and 2012. The 0.3-10 keV spectra consist of an ultrasoft component described by an accretion disc blackbody (kT_in = 39.6^{+11.2}_{-5.5} eV) and a power law due to the thermal Comptonization (Γ = 1.96^{+0.24}_{-0.31}) of the disc emission. The disc temperature inferred from the soft excess is at least a factor of 2 lower than that found for the canonical soft excess emission from radio-quiet NLS1s. The UV spectrum is described by a power law with photon index 3.05^{+0.56}_{-0.33}. The observed UV emission is too strong to arise from the accretion disc or the host galaxy, but can be attributed to a jet. The X-ray emission from RX J1633.3+4719 is variable with fractional variability amplitude Fvar = 13.5 ± 1.0 per cent. In contrast to radio-quiet active galactic nuclei (AGN), X-ray emission from the source becomes harder with increasing flux. The fractional rms variability increases with energy and the rms spectrum is well described by a constant disc component and a variable power-law continuum with the normalization and photon index being anticorrelated. Such spectral variability cannot be caused by variations in the absorption and must be intrinsic to the hot corona. Our finding of possible evidence for emission from the inner accretion disc, jet and hot corona from RX J1633.3+4719 in the optical to X-ray bands makes this object an ideal target to probe the disc-jet connection in AGN.

  11. Unveiling the structure of barred galaxies at 3.6 μm with the Spitzer survey of stellar structure in galaxies (S{sup 4}G). I. Disk breaks

    SciTech Connect

    Kim, Taehyun; Lee, Myung Gyoon; Gadotti, Dimitri A.; Muñoz-Mateos, Juan-Carlos; Sheth, Kartik; Madore, Barry F.; Ho, Luis C.; Elmegreen, Bruce; Knapen, Johan H.; Cisternas, Mauricio; Erroz-Ferrer, Santiago; Zaritsky, Dennis; Comerón, Sébastien; Laurikainen, Eija; Salo, Heikki; Holwerda, Benne; Hinz, Joannah L.; Buta, Ron; and others

    2014-02-20

    We have performed two-dimensional multicomponent decomposition of 144 local barred spiral galaxies using 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies. Our model fit includes up to four components (bulge, disk, bar, and a point source) and, most importantly, takes into account disk breaks. We find that ignoring the disk break and using a single disk scale length in the model fit for Type II (down-bending) disk galaxies can lead to differences of 40% in the disk scale length, 10% in bulge-to-total luminosity ratio (B/T), and 25% in bar-to-total luminosity ratios. We find that for galaxies with B/T ≥ 0.1, the break radius to bar radius, r {sub br}/R {sub bar}, varies between 1 and 3, but as a function of B/T the ratio remains roughly constant. This suggests that in bulge-dominated galaxies the disk break is likely related to the outer Lindblad resonance of the bar and thus moves outward as the bar grows. For galaxies with small bulges, B/T < 0.1, r {sub br}/R {sub bar} spans a wide range from 1 to 6. This suggests that the mechanism that produces the break in these galaxies may be different from that in galaxies with more massive bulges. Consistent with previous studies, we conclude that disk breaks in galaxies with small bulges may originate from bar resonances that may be also coupled with the spiral arms, or be related to star formation thresholds.

  12. Transition (LINER/HII) nuclei as evolved Composite (Seyfert 2/Starburst) nuclei

    NASA Astrophysics Data System (ADS)

    Storchi-Bergmann, Thaisa; Brandt, C. H.; Cid Fernandes, R.; Schmitt, H. R.; González Delgado, R.

    2004-11-01

    We compare the circumnuclear stellar population and environmental properies of Seyfert and Composite (Seyfert + Starburst) nuclei with those of LINERs and LINER/HII transition galaxies (TOs), and discuss evidence for evolution from Seyfert/Composite to LINER/TO nuclei.

  13. Student Exploration of Star Formation Rate in Three High-Redshift Galaxy Clusters: an NOAO/Spitzer Education and Public Outreach Project.

    NASA Astrophysics Data System (ADS)

    Loughran, Thomas; Mundy, C.; Colllingwood, C.

    2007-12-01

    Two students at Saint Joseph's High School (South Bend, IN) joined their teacher in a year-long, NOAO-Spitzer-sponsored research project exploring star formation rate (SFR) in three high red shift (z =.54 - .64) galaxy clusters (cl1037, cl1227, cl 1232). SFRs for each of 127 members of the three clusters, total cluster SFRs, morphology distribution and SFR-morphology relations were determined. Results were presented at a regional Intel Science and Engineering Fair, earning a First in Division--Intel Excellence in Computer Science award, and were published in the 2007 edition of the RBSE Journal. The students also produced a milestone map for the project, enabling other students (presenting) from subsequent years to climb into the research more efficiently. Associated public outreach activities were conducted, introducing some 2000 members of the public to multiwavelength astronomy and the Spitzer Space Telescope. In addition, the project received local newspaper coverage in the South Bend Tribune, with a subscription of 146,476. This poster highlights these research, educational, and public outreach facets of the project.

  14. Local Luminous Infrared Galaxies. III. Co-evolution of Black Hole Growth and Star Formation Activity?

    NASA Astrophysics Data System (ADS)

    Alonso-Herrero, Almudena; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang, Yiping; Hernán-Caballero, Antonio; Rigopoulou, Dimitra

    2013-03-01

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 × 107 M ⊙ using [Ne III] 15.56 μm and optical [O III] λ5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear ~1.5 kpc region, as estimated from the nuclear 11.3 μm PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.

  15. THE UNUSUAL VERTICAL MASS DISTRIBUTION OF NGC 4013 SEEN THROUGH THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

    SciTech Connect

    Comeron, Sebastien; Elmegreen, Bruce G.; Knapen, Johan H.; Sheth, Kartik; Munoz-Mateos, Juan-Carlos; Kim, Taehyun; Mizusawa, Trisha; Regan, Michael W.; Gil de Paz, Armando; Menendez-Delmestre, KarIn; Seibert, Mark; Ho, Luis C.; Laurikainen, Eija; Salo, Heikki; Laine, Jarkko; Athanassoula, E.; Bosma, Albert; Gadotti, Dimitri A.

    2011-09-10

    NGC 4013 is a nearby Sb edge-on galaxy known for its 'prodigious' H I warp and its 'giant' tidal stream. Previous work on this unusual object shows that it cannot be fitted satisfactorily by a canonical thin+thick disk structure. We have produced a new decomposition of NGC 4013, considering three stellar flattened components (thin+thick disk plus an extra and more extended component) and one gaseous disk. All four components are considered to be gravitationally coupled and isothermal. To do so, we have used the 3.6 {mu}m images from the Spitzer Survey of Stellar Structure in Galaxies. We find evidence for NGC 4013 indeed having a thin and a thick disk and an extra flattened component. This smooth and extended component (scale height z{sub EC} {approx} 3 kpc) could be interpreted as a thick disk or as a squashed ellipsoidal halo and contains {approx}20% of the total mass of all three stellar components. We argue it is unlikely to be related to the ongoing merger or due to the off-plane stars from a warp in the other two disk components. Instead, we favor a scenario in which the thick disk and the extended component were formed in a two-stage process, in which an initially thick disk has been dynamically heated by a merger soon enough in the galaxy history to have a new thick disk formed within it.

  16. PROBING THE INTERSTELLAR MEDIUM OF z {approx} 1 ULTRALUMINOUS INFRARED GALAXIES THROUGH INTERFEROMETRIC OBSERVATIONS OF CO AND SPITZER MID-INFRARED SPECTROSCOPY

    SciTech Connect

    Pope, Alexandra; Kirkpatrick, Allison; Wagg, Jeff; Frayer, David; Armus, Lee; Chary, Ranga-Ram; Desai, Vandana; Daddi, Emanuele; Elbaz, David; Gabor, Jared

    2013-08-01

    We explore the relationship between gas, dust, and star formation in a sample of 12 ultraluminous infrared galaxies (ULIRGs) at high-redshift compared to a similar sample of local galaxies. We present new CO observations and/or Spitzer mid-IR spectroscopy for six 70 {mu}m selected galaxies at z {approx} 1 in order to quantify the properties of the molecular gas reservoir, the contribution of an active galactic nucleus (AGN) to the mid-IR luminosity, and the star formation efficiency (SFE = L{sub IR}/L{sup '}{sub CO}). The mid-IR spectra show strong polycyclic aromatic hydrocarbon (PAH) emission, and our spectral decomposition suggests that the AGN makes a minimal contribution (<25%) to the mid-IR luminosity. The 70 {mu}m selected ULIRGs, which we find to be spectroscopic close pairs, are observed to have high SFE, similar to local ULIRGs and high-redshift submillimeter galaxies, consistent with enhanced IR luminosity due to an ongoing major merger. Combined with existing observations of local and high-redshift ULIRGs, we further compare the PAH, IR, and CO luminosities. We show that the ratio L{sub PAH,6.2}/L{sub IR} decreases with increasing IR luminosity for both local and high-redshift galaxies, but the trend for high-redshift galaxies is shifted to higher IR luminosities; the average L{sub PAH,6.2}/L{sub IR} ratio at a given L{sub IR} is {approx}3 times higher at high-redshift. When we normalize by the molecular gas, we find this trend to be uniform for galaxies at all redshifts and that the molecular gas is correlated with the PAH dust emission. The similar trends seen in the [C II] to molecular gas ratios in other studies suggests that PAH emission, like [C II], continues to be a good tracer of photodissociation regions even at high-redshift. Together the CO, PAH, and far-IR fine structure lines should be useful for constraining the interstellar medium conditions in high-redshift galaxies.

  17. The First GeV Outburst of the Radio-loud Narrow-line Seyfert 1 Galaxy PKS 1502+036

    NASA Astrophysics Data System (ADS)

    Paliya, Vaidehi S.; Stalin, C. S.

    2016-03-01

    The γ-ray-loud narrow-line Seyfert 1 (γ-NLSy1) galaxy PKS 1502+036 (z = 0.409) exhibited its first γ-ray outburst on 2015 December 20. In the energy range of 0.1-300 GeV, the highest flux measured by the Fermi-Large Area Telescope is (3.90 ± 1.52) × 10-6 {ph} {{cm}}-2 {{{s}}}-1, which is the highest γ-ray flux ever detected from this object. The associated spectral shape is soft (Γ0.1-300 GeV = 2.57 ± 0.17) and this corresponds to an isotropic γ-ray luminosity of (1.2 ± 0.6) × 1048 erg s-1. We generate the broadband spectral energy distribution (SED) during the GeV flare and reproduce it using a one-zone leptonic emission model. The optical-UV spectrum can be explained by a combination of synchrotron and accretion disk emission, whereas the X-ray-to-γ-ray SED can be satisfactorily reproduced by inverse-Compton scattering of thermal photons that originated from the torus. The derived SED parameters hint that the increase in the bulk Lorentz factor is a major cause of the flare and the location of the emission region is estimated as being outside the broad-line region but still inside the torus. A comparison of the GeV-flaring SED of PKS 1502+036 with that of two other γ-NLSy1 galaxies, namely, 1H 0323+342 (z = 0.061) and PMN J0948+0022 (z = 0.585), and also with flat spectrum radio quasar (FSRQ) 3C 279 (z = 0.536), has led to the conclusion that the GeV-flaring SEDs of γ-NLSy1 galaxies resemble FSRQs and a major fraction of their bolometric luminosities are emitted at γ-ray energies.

  18. The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447. I. The X-ray View

    NASA Astrophysics Data System (ADS)

    Kreikenbohm, A.; Schulz, R.; Kadler, M.; Wilms, J.; Markowitz, A.; Chang, C. S.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Mannheim, K.; Müller, C.; Ojha, R.; Ros, E.; Trüstedt, J.

    2016-01-01

    As part of the TANAMI multiwavelength progam, we discuss new X-ray observations of the γ-ray and radio-loud narrow line Seyfert 1 galaxy (γ-NLS1) PKS 2004-447. The active galaxy is a member of a small sample of radio-loud NLS1s detected in γ-rays by the Fermi Large Area Telescope. It stands out for being the radio-loudest and the only southern-hemisphere source in this sample. We present results from our X-ray monitoring program comprised of Swift snapshot observations from 2012 through 2014 and two new X-ray observations with XMM-Newton in 2012. Supplemented by archival data from 2004 and 2011, our data set allows for a careful analysis of the X-ray spectrum and variability of this peculiar source. The (0.5-10) keV spectrum is described well by a power law (Γ ~ 1.6), which can be interpreted as non-thermal emission from a relativistic jet. The source exhibits moderate flux variability on timescales of both months and years. Correlated brightness variations in the (0.5-2) keV and (2-10) keV bands are explained by a single variable spectral component, such as the one from the jet. A possible soft excess seen in the data from 2004 cannot be confirmed by the new XMM-Newton observations taken during low-flux states. Any contribution to the total flux in 2004 is less than 20% of the power-law component. The (0.5-10) keV luminosities of PKS 2004-447 are in the range of (0.5-2.7) × 1044 erg s-1. A comparison of the X-ray properties among the known γ-NLS1 galaxies shows that in four out of five cases the X-ray spectrum is dominated by a flat power law without intrinsic absorption. These objects are moderately variable in their brightness, while spectral variability is observed in at least two sources. The major difference across the X-ray spectra of γ-NLS1s is the luminosity, which spans a range of almost two orders of magnitude from 1044 erg s-1 to 1046 erg s-1 in the (0.5-10) keV band.

  19. THE OPTICAL SPECTRA OF SPITZER 24 mum GALAXIES IN THE COSMIC EVOLUTION SURVEY FIELD. II. FAINT INFRARED SOURCES IN THE zCOSMOS-BRIGHT 10k CATALOG

    SciTech Connect

    Caputi, K. I.; Lilly, S. J.; Maier, C.; Carollo, C. M.; Aussel, H.; Floc'h, E. Le; Frayer, D.; Contini, T.; Kneib, J.-P.; Le Fevre, O.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Scoville, N.; Zamorani, G.; Bardelli, S.; Bolzonella, M.; Coppa, G.; Bongiorno, A.

    2009-12-20

    We have used the zCOSMOS-bright 10k sample to identify 3244 Spitzer/MIPS 24 mum-selected galaxies with 0.06 mJy < S{sub 24{sub m}}u{sub m} approx< 0.50 mJy and I{sub AB} < 22.5, over 1.5 deg{sup 2} of the COSMOS field, and studied different spectral properties, depending on redshift. At 0.2 < z < 0.3, we found that different reddening laws of common use in the literature explain the dust extinction properties of approx80% of our infrared (IR) sources, within the error bars. For up to 16% of objects, instead, the Halpha lambda6563/Hbeta lambda4861 ratios are too high for their IR/UV attenuations, which is probably a consequence of inhomogeneous dust distributions. In only a few of our galaxies at 0.2 < z < 0.3, the IR emission could be mainly produced by dust heated by old rather than young stars. Besides, the line ratios of approx22% of our galaxies suggest that they might be star-formation/nuclear-activity composite systems. At 0.5 < z < 0.7, we estimated galaxy metallicities for 301 galaxies: at least 12% of them are securely below the upper-branch mass-metallicity trend, which is consistent with the local relation. Finally, we performed a combined analysis of the H{sub d}elta equivalent width versus D{sub n} (4000) diagram for 1722 faint and bright 24 mum galaxies at 0.6 < z < 1.0, spanning two decades in mid-IR luminosity. We found that, while secondary bursts of star formation are necessary to explain the position of the most luminous IR galaxies in that diagram, quiescent, exponentially declining star formation histories can well reproduce the spectral properties of approx40% of the less luminous sources. Our results suggest a transition in the possible modes of star formation at total IR luminosities L{sub TIR} approx (3 +- 2) x 10{sup 11} L{sub sun}.

  20. AN INFRARED CENSUS OF DUST IN NEARBY GALAXIES WITH SPITZER (DUSTiNGS). II. DISCOVERY OF METAL-POOR DUSTY AGB STARS

    SciTech Connect

    Boyer, Martha L.; Sonneborn, George; McQuinn, Kristen B. W.; Gehrz, Robert D.; Skillman, Evan; Barmby, Pauline; Bonanos, Alceste Z.; Gordon, Karl D.; Meixner, Margaret; Groenewegen, M. A. T.; Lagadec, Eric; Lennon, Daniel; Marengo, Massimo; McDonald, Iain; Zijlstra, Albert; Sloan, G. C.; Van Loon, Jacco Th.

    2015-02-10

    The DUSTiNGS survey (DUST in Nearby Galaxies with Spitzer) is a 3.6 and 4.5 μm imaging survey of 50 nearby dwarf galaxies designed to identify dust-producing asymptotic giant branch (AGB) stars and massive stars. Using two epochs, spaced approximately six months apart, we identify a total of 526 dusty variable AGB stars (sometimes called ''extreme'' or x-AGB stars; [3.6]-[4.5] > 0.1 mag). Of these, 111 are in galaxies with [Fe/H] < –1.5 and 12 are in galaxies with [Fe/H] < –2.0, making them the most metal-poor dust-producing AGB stars known. We compare these identifications to those in the literature and find that most are newly discovered large-amplitude variables, with the exception of ≈30 stars in NGC 185 and NGC 147, 1 star in IC 1613, and 1 star in Phoenix. The chemical abundances of the x-AGB variables are unknown, but the low metallicities suggest that they are more likely to be carbon-rich than oxygen-rich and comparisons with existing optical and near-IR photometry confirm that 70 of the x-AGB variables are confirmed or likely carbon stars. We see an increase in the pulsation amplitude with increased dust production, supporting previous studies suggesting that dust production and pulsation are linked. We find no strong evidence linking dust production with metallicity, indicating that dust can form in very metal-poor environments.

  1. SPITZER MID-IR SPECTROSCOPY OF POWERFUL 2 JY AND 3CRR RADIO GALAXIES. I. EVIDENCE AGAINST A STRONG STARBURST-AGN CONNECTION IN RADIO-LOUD AGN

    SciTech Connect

    Dicken, D.; Axon, D.; Robinson, A.; Kharb, P.; Tadhunter, C.; Ramos Almeida, C.; Morganti, R.; Kouwenhoven, M. B. N.; Spoon, H.; Inskip, K. J.; Holt, J.; Nesvadba, N. P. H.

    2012-02-01

    We present deep Spitzer/Infrared Spectrograph (IRS) spectra for complete samples of 46 2 Jy radio galaxies (0.05 < z < 0.7) and 19 3CRR FRII radio galaxies (z < 0.1), and use the detection of polycyclic aromatic hydrocarbon (PAH) features to examine the incidence of contemporaneous star formation and radio-loud active galactic nucleus (AGN) activity. Our analysis reveals PAH features in only a minority (30%) of the objects with good IRS spectra. Using the wealth of complementary data available for the 2 Jy and 3CRR samples we make detailed comparisons between a range of star formation diagnostics: optical continuum spectroscopy, mid- to far-IR (MFIR) color, far-IR excess and PAH detection. There is good agreement between the various diagnostic techniques: most candidates identified to have star formation activity on the basis of PAH detection are also identified using at least two of the other techniques. We find that only 35% of the combined 2 Jy and 3CRR sample show evidence for recent star formation activity (RSFA) at optical and/or MFIR wavelengths. This result argues strongly against the idea of a close link between starburst and powerful radio-loud AGN activity, reinforcing the view that, although a large fraction of powerful radio galaxies may be triggered in galaxy interactions, only a minority are triggered at the peaks of star formation activity in major, gas-rich mergers. However, we find that compact radio sources (D < 15 kpc) show a significantly higher incidence of RSFA (>75%) than their more extended counterparts ( Almost-Equal-To 15%-25%). We discuss this result in the context of a possible bias toward the selection of compact radio sources triggered in gas-rich environments.

  2. Short-term radio variability and parsec-scale structure in A gamma-ray narrow-line Seyfert 1 galaxy 1H 0323+342

    SciTech Connect

    Wajima, Kiyoaki; Fujisawa, Kenta; Hayashida, Masaaki; Isobe, Naoki; Ishida, Takafumi; Yonekura, Yoshinori

    2014-02-01

    We made simultaneous single-dish and very long baseline interferometer (VLBI) observations of a narrow-line Seyfert 1 galaxy 1H 323+342, showing gamma-ray activity revealed by Fermi/Large Area Telescope observations. We found significant variation of the total flux density at 8 GHz on the timescale of one month by the single-dish monitoring. The total flux density varied by 5.5% in 32 days, which is comparable to the gamma-ray variability timescale, corresponding to the variability brightness temperature of 7.0 × 10{sup 11} K. The source consists of central and southeastern components on the parsec (pc) scale. Only the flux of the central component decreased in the same way as the total flux density, indicating that the short-term radio variability, and probably the gamma-ray-emitting region, is associated with this component. From the VLBI observations, we obtained brightness temperatures of greater than (5.2 ± 0.3) × 10{sup 10} K and derived an equipartition Doppler factor of greater than 1.7, a variability Doppler factor of 2.2, and an 8 GHz radio power of 10{sup 24.6} W Hz{sup –1}. Combining them, we conclude that acceleration of radio jets and creation of high-energy particles are ongoing in the central engine and that the apparent very radio-loud feature of the source is due to the Doppler boosting effect, resulting in the intrinsic radio loudness being an order of magnitude smaller than the observed values. We also conclude that the pc-scale jet represents recurrent activity from the spectral fitting and the estimated kinematic age of pc- and kpc-scale extended components with different position angles.

  3. Simultaneous UV and X-ray Spectroscopy of the Seyfert 1 Galaxy NGC 5548. I: Physical Conditions in the UV Absorbers

    NASA Technical Reports Server (NTRS)

    Crenshaw, D. M.; Kraemer, S. B.; Gabel, J. R.; Kaastra, J. S.; Steenbrugge, K. C.; Brinkman, A. C.; Dunn, J. P.; George, I. M.; Liedahl, D. A.; Paerels, F. B. S.

    2003-01-01

    We present new UV spectra of the nucleus of the Seyfert 1 galaxy NGC 5548, which we obtained with the Space Telescope Imaging Spectrograph at high spectral resolution, in conjunction with simultaneous Chandra X-ray Observatory spectra. Taking advantage of the low UV continuum and broad emission-line fluxes, we have determined that the deepest UV absorption component covers at least a portion of the inner, high-ionization narrow-line region (NLR). We find nonunity covering factors in the cores of several kinematic components, which increase the column density measurements of N V and C IV by factors of 1.2 to 1.9 over the full-covering case; however, the revised columns have only a minor effect on the parameters derived from our photoionization models. For the first time, we have simultaneous N V and C IV columns for component 1 (at -1040 km/s), and find that this component cannot be an X-ray warm absorber, contrary to our previous claim based on nonsimultaneous observations. We find that models of the absorbers based on solar abundances severely overpredict the O VI columns previously obtained with the Far Ultraviolet Spectrograph, and present arguments that this is not likely due to variability. However, models that include either enhanced nitrogen (twice solar) or dust, with strong depletion of carbon in either case, are successful in matching all of the observed ionic columns. These models result in substantially lower ionization parameters and total column densities compared to dust-free solar-abundance models, and produce little O VII or O VIII, indicating that none of the UV absorbers are X-ray warm absorbers.

  4. Radio-to-Gamma-Ray Monitoring of the Narrow-line Seyfert 1 Galaxy PMN J0948+0022 from 2008 to 2011

    NASA Technical Reports Server (NTRS)

    Foschini, L.; Angelakis, E.; Fuhrmann, L.; Ghisellini, G.; Hovatta, T.; Lahteenmaki, A.; Lister, M. L.; Braito, V.; Gallo, L.; Hamilton, T. S.; Kino, M.; Komossa S.; Pushkarev, A. B.; Thompson, D. J.; Tibolla, O.; Tramacere, A.; Carrasco, L.; Carraminana, A.; Falcone, A.; Giroletti, M.; Grupe, D.; Kovalev, Y. Y.; Krichbaum, T. P.; Max-Moerbeck, W.; Nestoras, I.; Pearson, T.J.; Porras, A.; Readhead, A.C.S.; Recillas, E.; Richards, J.L.; Riquelme, D.; Sievers, A.; Tammi, J.; Ungerechts, H.

    2012-01-01

    We present more than three years of observations at different frequencies, from radio to high-energy ?-rays, of the Narrow-Line Seyfert 1 (NLS1) Galaxy PMN J0948+0022 (z = 0.585). This source is the first NLS1 detected at energies above 100 MeV and therefore can be considered the prototype of this emerging new class of ?-ray emitting active galactic nuclei (AGN). The observations performed from 2008 August 1 to 2011 December 31 confirmed that PMN J0948+0022 generates a powerful relativistic jet, which is able to develop an isotropic luminosity at gamma-rays of the order of 1048 erg per second, at the level of powerful quasars. The evolution of the radiation emission of this source in 2009 and 2010 followed the canonical expectations of relativistic jets with correlated multiwavelength variability (gamma-rays followed by radio emission after a few months), but it was difficult to retrieve a similar pattern in the light curves of 2011. The comparison of gamma-ray spectra before and including 2011 data suggested that there was a softening of the highenergy spectral slope. We selected five specific epochs to be studied by modelling the broad-band spectrum, which are characterised by an outburst at gamma-rays or very low/high flux at other wavelengths. The observed variability can largely be explained by changes in the injected power, the bulk Lorentz factor of the jet, or the electron spectrum. The characteristic time scale of doubling/halving flux ranges from a few days to a few months, depending on the frequency and the sampling rate. The shortest doubling time scale at gamma-rays is 2.3 +/- 0.5 days. These small values underline the need of highly sampled multiwavelength campaigns to better understand the physics of these sources.

  5. CORONAL PROPERTIES OF THE SEYFERT 1.9 GALAXY MCG-05-23-016 DETERMINED FROM HARD X-RAY SPECTROSCOPY WITH NuSTAR

    SciTech Connect

    Baloković, M.; Harrison, F. A.; Esmerian, C. J.; Fürst, F.; Walton, D. J.; Matt, G.; Marinucci, A.; Zoghbi, A.; Reynolds, C. S.; Ballantyne, D. R.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Fabian, A. C.; Parker, M. L.; Hailey, C. J.; Stern, D.; Zhang, W. W.

    2015-02-10

    Measurements of the high-energy cut-off in the coronal continuum of active galactic nuclei have long been elusive for all but a small number of the brightest examples. We present a direct measurement of the cut-off energy in the nuclear continuum of the nearby Seyfert 1.9 galaxy MCG-05-23-016 with unprecedented precision. The high sensitivity of NuSTAR up to 79 keV allows us to clearly disentangle the spectral curvature of the primary continuum from that of its reflection component. Using a simple phenomenological model for the hard X-ray spectrum, we constrain the cut-off energy to 116{sub −5}{sup +6} keV with 90% confidence. Testing for more complex models and nuisance parameters that could potentially influence the measurement, we find that the cut-off is detected robustly. We further use simple Comptonized plasma models to provide independent constraints for both the kinetic temperature of the electrons in the corona and its optical depth. At the 90% confidence level, we find kT{sub e} = 29 ± 2 keV and τ {sub e} = 1.23 ± 0.08 assuming a slab (disk-like) geometry, and kT{sub e} = 25 ± 2 keV and τ {sub e} = 3.5 ± 0.2 assuming a spherical geometry. Both geometries are found to fit the data equally well and their two principal physical parameters are correlated in both cases. With the optical depth in the τ {sub e} ≳ 1 regime, the data are pushing the currently available theoretical models of the Comptonized plasma to the limits of their validity. Since the spectral features and variability arising from the inner accretion disk have been observed previously in MCG-05-23-016, the inferred high optical depth implies that a spherical or disk-like corona cannot be homogeneous.

  6. Variable Reddening and Broad Absorption Lines in the Narrow-line Seyfert 1 Galaxy WPVS 007: An Origin in the Torus

    NASA Astrophysics Data System (ADS)

    Leighly, Karen M.; Cooper, Erin; Grupe, Dirk; Terndrup, Donald M.; Komossa, S.

    2015-08-01

    We report the discovery of an occultation event in the low-luminosity narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert with longer timescale variability, these observations place strong constraints on the nature and location of the absorbing material. Swift monitoring has revealed a secular decrease since ∼2010 accompanied by flattening of the optical and UV photometry that suggests variable reddening. Analysis of four Hubble Space Telescope COS observations since 2010, including a Director’s Discretionary time observation during the occultation, shows that the broad-absorption-line velocity offset and the C iv emission-line width both decrease as the reddening increases. The occultation dynamical timescale, the BAL variability dynamical timescale, and the density of the BAL gas show that both the reddening material and the broad-absorption-line gas are consistent with an origin in the torus. These observations can be explained by a scenario in which the torus is clumpy with variable scale height, and the BAL gas is blown from the torus material like spray from the crest of a wave. As the obscuring material passes into our line of sight, we alternately see high-velocity broad absorption lines and a clear view to the central engine, or low-velocity broad absorption lines and strong reddening. WPVS 007 has a small black hole mass, and correspondingly short timescales, and so we may be observing behavior that is common in BALQSOs, but is not typically observable. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 11733, 13015, and 14058.

  7. STRONG UV AND X-RAY VARIABILITY OF THE NARROW LINE SEYFERT 1 GALAXY WPVS 007-ON THE NATURE OF THE X-RAY LOW STATE

    SciTech Connect

    Grupe, Dirk; Barlow, Brad N.; Komossa, S.; Scharwaechter, Julia; Dietrich, Matthias; Leighly, Karen M.; Lucy, Adrian E-mail: julia.scharwaechter@obspm.fr

    2013-10-01

    We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS1) galaxy WPVS 007. The galaxy was monitored with Swift between 2005 October and 2013 July, after it had previously undergone a dramatic drop in its X-ray flux. For the first time, we are able to repeatedly detect this NLS1 in X-rays again. This increased number of detections in the last couple of years may suggest that the strong absorber that has been found in this active galactic nucleus (AGN) is starting to become leaky and may eventually disappear. The X-ray spectra obtained for WPVS 007 are all consistent with a partial covering absorber model. A spectrum based on the data during the extreme low X-ray flux states shows that the absorption column density is of the order of 4 Multiplication-Sign 10{sup 23} cm{sup -2} with a covering fraction of 95%. WPVS 007 also displays one of the strongest UV variabilities seen in NLS1s. The UV continuum variability anti-correlates with the optical/UV slope {alpha}{sub UV}, which suggests that the variability may be primarily due to reddening. The UV variability timescales are consistent with moving dust ''clouds'' located beyond the dust sublimation radius of R{sub sub} Almost-Equal-To 20 lt-days. We present for the first time near-infrared JHK data of WPVS 007, which reveal a rich emission-line spectrum. Recent optical spectroscopy does not indicate significant variability in the broad permitted and Fe II emission lines, implying that the ionizing continuum seen by those gas clouds has not significantly changed over the last decades. All X-ray and UV observations are consistent with a scenario in which an evolving broad absorption line (BAL) flow obscures the continuum emission. As such, WPVS 007 is an important target for our understanding of BAL flows in low-mass AGNs.

  8. The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447. II. The radio view

    NASA Astrophysics Data System (ADS)

    Schulz, R.; Kreikenbohm, A.; Kadler, M.; Ojha, R.; Ros, E.; Stevens, J.; Edwards, P. G.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Großberger, C.; Hase, H.; Horiuchi, S.; Lovell, J. E. J.; Mannheim, K.; Markowitz, A.; Müller, C.; Phillips, C.; Plötz, C.; Quick, J.; Trüstedt, J.; Tzioumis, A. K.; Wilms, J.

    2016-04-01

    Context. Γ-ray-detected radio-loud narrow-line Seyfert 1 (γ-NLS1) galaxies constitute a small but interesting sample of the γ-ray-loud AGN. The radio-loudest γ-NLS1 known, PKS 2004-447, is located in the southern hemisphere and is monitored in the radio regime by the multiwavelength monitoring programme TANAMI. Aims: We aim for the first detailed study of the radio morphology and long-term radio spectral evolution of PKS 2004-447, which are essential for understanding the diversity of the radio properties of γ-NLS1s. Methods: The TANAMI VLBI monitoring program uses the Australian Long Baseline Array (LBA) and telescopes in Antarctica, Chile, New Zealand, and South Africa to monitor the jets of radio-loud active galaxies in the southern hemisphere. Lower resolution radio flux density measurements at multiple radio frequencies over four years of observations were obtained with the Australia Telescope Compact Array (ATCA). Results: The TANAMI VLBI image at 8.4 GHz shows an extended one-sided jet with a dominant compact VLBI core. Its brightness temperature is consistent with equipartition, but it is an order of magnitude below other γ-NLS1s with the sample value varying over two orders of magnitude. We find a compact morphology with a projected large-scale size < 11 kpc and a persistent steep radio spectrum with moderate flux-density variability. Conclusions: PKS 2004-447 appears to be a unique member of the γ-NLS1 sample. It exhibits blazar-like features, such as a flat featureless X-ray spectrum and a core-dominated, one-sided parsec-scale jet with indications for relativistic beaming. However, the data also reveal properties atypical for blazars, such as a radio spectrum and large-scale size consistent with compact-steep-spectrum (CSS) objects, which are usually associated with young radio sources. These characteristics are unique among all γ-NLS1s and extremely rare among γ-ray-loud AGN. The VLBI images shown in Figs. 3 and 4 (as FITS files) and the ATCA

  9. THE EVOLUTION OF DUSTY STAR FORMATION IN GALAXY CLUSTERS TO z = 1: SPITZER INFRARED OBSERVATIONS OF THE FIRST RED-SEQUENCE CLUSTER SURVEY

    SciTech Connect

    Webb, T. M. A.; O'Donnell, D.; Coppin, Kristen; Faloon, Ashley; Geach, James E.; Noble, Allison; Yee, H. K. C.; Gilbank, David; Ellingson, Erica; Gladders, Mike; Muzzin, Adam; Wilson, Gillian; Yan, Renbin

    2013-10-01

    We present the results of an infrared (IR) study of high-redshift galaxy clusters with the MIPS camera on board the Spitzer Space Telescope. We have assembled a sample of 42 clusters from the Red-Sequence Cluster Survey-1 over the redshift range 0.3 < z < 1.0 and spanning an approximate range in mass of 10{sup 14-15} M {sub ☉}. We statistically measure the number of IR-luminous galaxies in clusters above a fixed inferred IR luminosity of 2 × 10{sup 11} M {sub ☉}, assuming a star forming galaxy template, per unit cluster mass and find it increases to higher redshift. Fitting a simple power-law we measure evolution of (1 + z){sup 5.1±1.9} over the range 0.3 < z < 1.0. These results are tied to the adoption of a single star forming galaxy template; the presence of active galactic nuclei, and an evolution in their relative contribution to the mid-IR galaxy emission, will alter the overall number counts per cluster and their rate of evolution. Under the star formation assumption we infer the approximate total star formation rate per unit cluster mass (ΣSFR/M {sub cluster}). The evolution is similar, with ΣSFR/M {sub cluster} ∼ (1 + z){sup 5.4±1.9}. We show that this can be accounted for by the evolution of the IR-bright field population over the same redshift range; that is, the evolution can be attributed entirely to the change in the in-falling field galaxy population. We show that the ΣSFR/M {sub cluster} (binned over all redshift) decreases with increasing cluster mass with a slope (ΣSFR/M{sub cluster}∼M{sub cluster}{sup -1.5±0.4}) consistent with the dependence of the stellar-to-total mass per unit cluster mass seen locally. The inferred star formation seen here could produce ∼5%-10% of the total stellar mass in massive clusters at z = 0, but we cannot constrain the descendant population, nor how rapidly the star-formation must shut-down once the galaxies have entered the cluster environment. Finally, we show a clear decrease in the number of IR

  10. Size and physical conditions of the coronal line region in a nearby Seyfert 2: the Circinus galaxy

    NASA Astrophysics Data System (ADS)

    Oliva, E.; Salvati, M.; Moorwood, A. F. M.; Marconi, A.

    1994-08-01

    We present observations of visible ([FeVII], [FeX], [FeXI], [SVIII]) and near infrared ([SIX], [SiVI], [CaVIII], [SiVII], [SiIX]) coronal lines in the Circinus galaxy. The number of detected lines, their velocity profiles, and their spatial distribution pose tight constraints on models of the coronal line region (CLR), and lead to several important conclusions. We can exclude fast shocks and hot stars (warmers) as the origin of the coronal line emission, and find convincing (although not conclusive) evidence against a hot, collisionally ionized plasma. The CLR appears to be a dense (N_e_=~250cm^-3^), compact (diameter=~10pc), dustless region photoionized by the nuclear continuum which must be remarkably flat (Lnu_=~ν^-0.5^) around 300eV.

  11. UM 625 REVISITED: MULTIWAVELENGTH STUDY OF A SEYFERT 1 GALAXY WITH A LOW-MASS BLACK HOLE

    SciTech Connect

    Jiang Ning; Dong Xiaobo; Yang Huan; Wang Junxian; Ho, Luis C. E-mail: xbdong@ustc.edu.cn

    2013-06-10

    UM 625, previously identified as a narrow-line active galactic nucleus (AGN), actually exhibits broad H{alpha} and H{beta} lines whose width and luminosity indicate a low black hole (BH) mass of 1.6 Multiplication-Sign 10{sup 6} M{sub Sun }. We present a detailed multiwavelength study of the nuclear and host galaxy properties of UM 625. Analysis of Chandra and XMM-Newton observations suggests that this system contains a heavily absorbed and intrinsically X-ray weak ({alpha}{sub ox} = -1.72) nucleus. Although not strong enough to qualify as radio loud, UM 625 does belong to a minority of low-mass AGNs detected in the radio. The broadband spectral energy distribution constrains the bolometric luminosity to L{sub bol} Almost-Equal-To (0.5-3) Multiplication-Sign 10{sup 43} erg s{sup -1} and L{sub bol}/L{sub Edd} Almost-Equal-To 0.02-0.15. A comprehensive analysis of Sloan Digital Sky Survey and Hubble Space Telescope images shows that UM 625 is a nearly face-on S0 galaxy with a prominent, relatively blue pseudobulge (Sersic index n = 1.60) that accounts for {approx}60% of the total light in the R band. The extended disk is featureless, but the central {approx}150-400 pc contains a conspicuous semi-ring of bright, blue star-forming knots, whose integrated ultraviolet luminosity suggests a star formation rate of {approx}0.3 M{sub Sun} yr{sup -1}. The mass of the central BH roughly agrees with the value predicted from its bulge velocity dispersion but is significantly lower than that expected from its bulge luminosity.

  12. IRAS observations of active galaxies

    NASA Technical Reports Server (NTRS)

    Neugebauer, G.; Soifer, B. T.; Rowan-Robinson, M.

    1985-01-01

    The IRAS survey gives an unbiased view of the infrared properties of the active galaxies. Seyfert galaxies occupy much the same area in color-color plots as to normal infrared bright galaxies, but extend the range towards flatter 60 to 25 mm slopes. Statistically the Seyfert 1 galaxies can be distinguished from the Seyfert 2 galaxies, lying predominantly closer to the area with constant slopes between 25 and 200 mm. The infrared measurements of the Seyfert galaxies cannot distinguish between the emission mechanisms in these objects although they agree with the currently popular ideas; they do provide a measure of the total luminosity of the Seyferts. The quasar's position in the color-color diagrams continue the trend of the Seyferts. The quasar 3C48 is shown to be exceptional among the radio loud quasars in that it has a high infrared luminosity which dominates the power output of the quasar and is most likely associated with the underlying host galaxy.

  13. SACS: Spitzer Archival Cluster Survey

    NASA Astrophysics Data System (ADS)

    Stern, Daniel

    Emerging from the cosmic web, galaxy clusters are the most massive gravitationally bound structures in the universe. Thought to have begun their assembly at z > 2, clusters provide insights into the growth of large-scale structure as well as the physics that drives galaxy evolution. Understanding how and when the most massive galaxies assemble their stellar mass, stop forming stars, and acquire their observed morphologies in these environments remain outstanding questions. The redshift range 1.3 < z < 2 is a key epoch in this respect: elliptical galaxies start to become the dominant population in cluster cores, and star formation in spiral galaxies is being quenched. Until recently, however, this redshift range was essentially unreachable with available instrumentation, with clusters at these redshifts exceedingly challenging to identify from either ground-based optical/nearinfrared imaging or from X-ray surveys. Mid-infrared (MIR) imaging with the IRAC camera on board of the Spitzer Space Telescope has changed the landscape. High-redshift clusters are easily identified in the MIR due to a combination of the unique colors of distant galaxies and a negative k-correction in the 3-5 μm range which makes such galaxies bright. Even 90-sec observations with Spitzer/IRAC, a depth which essentially all extragalactic observations in the archive achieve, is sufficient to robustly detect overdensities of L* galaxies out to z~2. Here we request funding to embark on a ambitious scientific program, the “SACS: Spitzer Archival Cluster Survey”, a comprehensive search for the most distant galaxy clusters in all Spitzer/IRAC extragalactic pointings available in the archive. With the SACS we aim to discover ~2000 of 1.3 < z < 2.5 clusters, thus provide the ultimate catalog for high-redshift MIR selected clusters: a lasting legacy for Spitzer. The study we propose will increase by more than a factor of 10 the number of high-redshift clusters discovered by all previous surveys

  14. Resolving the Large Scale Spectral Variability of the Luminous Seyfert 1 Galaxy 1H 0419-577: Evidence for a New Emission Component and Absorption by Cold Dense Matter

    NASA Technical Reports Server (NTRS)

    Pounds, K. A.; Reeves, J. N.; Page, K. L.; OBrien, P. T.

    2004-01-01

    An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in September 2002, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below -1 keV. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was X-ray bright indicated the dominant spectral variability was due to a steep power law or cool Comptonised thermal emission. Four further XMM-Newton observations, with 1H 0419-577 in intermediate flux states, now support that conclusion, while we also find the variable emission component in intermediate state difference spectra to be strongly modified by absorption in low ionisation matter. The variable soft excess then appears to be an artefact of absorption of the underlying continuum while the core soft emission can be attributed to re- combination in an extended region of more highly ionised gas. We note the wider implications of finding substantial cold dense matter overlying (or embedded in) the X-ray continuum source in a luminous Seyfert 1 galaxy.

  15. Large Binocular Telescope and Spitzer Spectroscopy of Star-forming Galaxies at 1

    NASA Astrophysics Data System (ADS)

    Rujopakarn, W.; Rieke, G. H.; Papovich, C. J.; Weiner, B. J.; Rigby, J. R.; Rex, M.; Bian, F.; Kuhn, O. P.; Thompson, D.

    2012-08-01

    We present spectroscopic observations in the rest-frame optical and near- to mid-infrared wavelengths of four gravitationally lensed infrared (IR) luminous star-forming galaxies at redshift 1 Spitzer. The sample was selected to represent pure, actively star-forming systems, absent of active galactic nuclei. The large lensing magnifications result in high signal-to-noise spectra that can probe faint IR recombination lines, including Paα and Brα at high redshifts. The sample was augmented by three lensed galaxies with similar suites of unpublished data and observations from the literature, resulting in the final sample of seven galaxies. We use the IR recombination lines in conjunction with Hα observations to probe the extinction, Av , of these systems, as well as testing star formation rate (SFR) indicators against the SFR measured by fitting spectral energy distributions to far-IR photometry. Our galaxies occupy a range of Av from ~0 to 5.9 mag, larger than previously known for a similar range of IR luminosities at these redshifts. Thus, estimates of SFR even at z ~ 2 must take careful count of extinction in the most IR luminous galaxies. We also measure extinction by comparing SFR estimates from optical emission lines with those from far-IR measurements. The comparison of results from these two independent methods indicates a large variety of dust distribution scenarios at 1 < z < 3. Without correcting for dust extinction, the Hα SFR indicator underestimates the SFR; the size of the necessary correction depends on the IR luminosity and dust distribution scenario. Individual SFR estimates based on the 6.2 μm polycyclic aromatic hydrocarbon emission line luminosity do not show a systematic discrepancy with extinction, although a considerable, ~ 0.2 dex, scatter is observed. The LBT is an international collaboration among institutions in the United States, Italy

  16. GALAXY CLUSTERS AROUND RADIO-LOUD ACTIVE GALACTIC NUCLEI AT 1.3 < z < 3.2 AS SEEN BY SPITZER

    SciTech Connect

    Wylezalek, Dominika; Stern, Daniel; Eisenhardt, Peter R. M.; Galametz, Audrey; Vernet, Joeel; De Breuck, Carlos; Seymour, Nick; Brodwin, Mark; Gonzalez, Anthony H.; Hatch, Nina; Jarvis, Matt; Rettura, Alessandro; Stanford, Spencer A.; Stevens, Jason A.

    2013-05-20

    We report the first results from the Clusters Around Radio-Loud AGN program, a Cycle 7 and 8 Spitzer Space Telescope snapshot program to investigate the environments of a large sample of obscured and unobscured luminous radio-loud active galactic nuclei (AGNs) at 1.2 < z < 3.2. These data, obtained for 387 fields, reach 3.6 and 4.5 {mu}m depths of [3.6]{sub AB} = 22.6 and [4.5]{sub AB} = 22.9 at the 95% completeness level, which is two to three times fainter than L* in this redshift range. By using the color cut [3.6] - [4.5] > -0.1 (AB), which efficiently selects high-redshift (z > 1.3) galaxies of all types, we identify galaxy cluster member candidates in the fields of the radio-loud AGN. The local density of these Infrared Array Camera (IRAC)-selected sources is compared to the density of similarly selected sources in blank fields. We find that 92% of the radio-loud AGN reside in environments richer than average. The majority (55%) of the radio-loud AGN fields are found to be overdense at a {>=}2{sigma} level; 10% are overdense at a {>=}5{sigma} level. A clear rise in surface density of IRAC-selected sources toward the position of the radio-loud AGN strongly supports an association of the majority of the IRAC-selected sources with the radio-loud AGN. Our results provide solid statistical evidence that radio-loud AGN are likely beacons for finding high-redshift galaxy (proto-)clusters. We investigate how environment depends on AGN type (unobscured radio-loud quasars versus obscured radio galaxies), radio luminosity and redshift, finding no correlation with either AGN type or radio luminosity. We find a decrease in density with redshift, consistent with galaxy evolution for this uniform, flux-limited survey. These results are consistent with expectations from the orientation-driven AGN unification model, at least for the high radio luminosity regimes considered in this sample.

  17. RADIO VARIABILITY IN SEYFERT NUCLEI

    SciTech Connect

    Mundell, C. G.; Ferruit, P.; Nagar, N.; Wilson, A. S.

    2009-09-20

    Comparison of 8.4 GHz radio images of a sample of eleven, early-type Seyfert galaxies with previous observations reveals possible variation in the nuclear radio flux density in five of them over a seven year period. Four Seyferts (NGC 2110, NGC 3081, MCG -6-30-15, and NGC 5273) show a decline in their 8.4 GHz nuclear flux density between 1992 and 1999, while one (NGC 4117) shows an increase; the flux densities of the remaining six Seyferts (Mrk 607, NGC 1386, Mrk 620, NGC 3516, NGC 4968, and NGC 7465) have remained constant over this period. New images of MCG -5-23-16 are also presented. We find no correlation between radio variability and nuclear radio luminosity or Seyfert nuclear type, although the sample is small and dominated by type 2 Seyferts. Instead, a possible correlation between the presence of nuclear radio variability and the absence of hundred parsec-scale radio emission is seen, with four out of five marginally resolved or unresolved nuclei showing a change in nuclear flux density, while five out of six extended sources show no nuclear variability despite having unresolved nuclear sources. NGC 2110 is the only source in our sample with significant extended radio structure and strong nuclear variability ({approx}38% decline in nuclear flux density over seven years). The observed nuclear flux variability indicates significant changes are likely to have occurred in the structure of the nucleus on scales smaller than the VLA beam size (i.e., within the central {approx}0.''1 (15 pc)), between the two epochs, possibly due to the appearance and fading of new components or shocks in the jet, consistent with previous detection of subparsec-scale nuclear structure in this Seyfert. Our results suggest that all Seyferts may exhibit variation in their nuclear radio flux density at 8.4 GHz, but that variability is more easily recognized in compact sources in which emission from the variable nucleus is not diluted by unresolved, constant flux density radio jet

  18. The Nuclear Regions of the Seyfert Galaxy NGC 4151: Parsec-Scale H I Absorption and a Remarkable Radio Jet

    NASA Astrophysics Data System (ADS)

    Mundell, C. G.; Wrobel, J. M.; Pedlar, A.; Gallimore, J. F.

    2003-01-01

    Sensitive high angular and linear resolution radio images of the 240 pc radio jet in NGC 4151, imaged at linear resolutions of 0.3-2.6 pc using the VLBA and phased VLA at λ21 cm, are presented and reveal for the first time a faint, highly collimated jet (diameter <~1.4 pc) underlying discrete components, seen in lower resolution MERLIN and VLA images, that appear to be shocklike features associated with changes in direction as the jet interacts with small gas clouds within the central ~100 pc of the galaxy. In addition, λ21 cm spectral line imaging of the neutral hydrogen in the nuclear region reveals the spatial location, distribution, and kinematics of the neutral gas detected previously in a lower resolution MERLIN study. Neutral hydrogen absorption is detected against component C4W (E+F) as predicted by Mundell et al, but the absorption, extending over 3 pc, is spatially and kinematically complex on subparsec scales, suggesting the presence of small, dense gas clouds with a wide range of velocities and column densities. The main absorption component matches that detected in the MERLIN study, close to the systemic velocity (998 km s-1) of the galaxy, and is consistent with absorption through a clumpy neutral gas layer in the putative obscuring torus, with higher velocity blue- and redshifted systems with narrow line widths also detected across E+F. In this region, average column densities are high, lying in the range 2.7×1019TS

  19. Near-infrared continuum and 3.3 micrometer(s) polycyclic aromatic hydrocarbon imaging of the starburst ring in the type 1 Seyfert galaxy NGC 7469

    NASA Technical Reports Server (NTRS)

    Mazzarella, J. M.; Voit, G. M.; Soifer, B. T.; Matthews, K.; Graham, J. R.; Armus, L.; Shupe, D.

    1994-01-01

    High resolution near-infrared images of the type 1 Seyfert galaxy NGC 7469 have been obtained to probe its dusty nuclear environment. Direct J, H, and K images are relatively featureless, but residual images created by subtracting a smooth model based on best-fitting elliptical isophotes reveal a tight inner spiral whose high surface-brightness portions correspond to a previously detected 3 sec (1 kpc) diameter ring of radio continuum emission. The inner infrared spiral arms extended approximately equal to 4 sec NW and SE from the nucleus, and the NW arm joins up with large-scale spiral structure visible in the R band. The residual images also show a bar-like structure aligned with the brightest infrared/radio hotspots at PA approximately equal to 50 deg. Three infrared hotspots are detected which align remarkably well with 6 cm radio continuum sources. The near-infrared ring and the hotspots are visible in the residual images, and in a high-resolution direct K-band image restored to an effective resolution of 0.65 sec (FWHM) using the Richardson-Lucy algorithm. The infrared hotspots have luminosities of nuL(sub nu) (2.2 micrometer(s)) approximately equal to 10(exp 8) solar luminosity (M(sub k) approximately equal to -16 mag), suggesting they are either giant H II regions or individual supernovae. The two brightest regions may be associated with enhanced star formation triggered by orbit crowding of gas where spiral arms emerge from an inner bar. Narrowband (delta lambda/lambda approximately 1.5%) imaging in the 3.28 micrometer(s) dust emission feature and surrounding continuum confirms the 3 sec diameter 3.28 micrometer(s) emission region detected previously using multiaperture photometry. The extended polycyclic aromatic hydrocarbon (PAH) emission is slightly elongated and aligned with published 1O III1 line emission and 12.5 micrometer(s) continuum emission, apparently tracing the starburst. The presence of approximately equal to 25% of the total 3.28 micrometer

  20. Radio-to-γ-ray monitoring of the narrow-line Seyfert 1 galaxy PMN J0948 + 0022 from 2008 to 2011

    NASA Astrophysics Data System (ADS)

    Foschini, L.; Angelakis, E.; Fuhrmann, L.; Ghisellini, G.; Hovatta, T.; Lahteenmaki, A.; Lister, M. L.; Braito, V.; Gallo, L.; Hamilton, T. S.; Kino, M.; Komossa, S.; Pushkarev, A. B.; Thompson, D. J.; Tibolla, O.; Tramacere, A.; Carramiñana, A.; Carrasco, L.; Falcone, A.; Giroletti, M.; Grupe, D.; Kovalev, Y. Y.; Krichbaum, T. P.; Max-Moerbeck, W.; Nestoras, I.; Pearson, T. J.; Porras, A.; Readhead, A. C. S.; Recillas, E.; Richards, J. L.; Riquelme, D.; Sievers, A.; Tammi, J.; Tornikoski, M.; Ungerechts, H.; Zensus, J. A.; Celotti, A.; Bonnoli, G.; Doi, A.; Maraschi, L.; Tagliaferri, G.; Tavecchio, F.

    2012-12-01

    We present more than three years of observations at different frequencies, from radio to high-energy γ-rays, of the Narrow-Line Seyfert 1 (NLS1) Galaxy PMN J0948 + 0022 (z = 0.585). This source is the first NLS1 detected at energies above 100 MeV and therefore can be considered the prototype of this emerging new class of γ-ray emitting active galactic nuclei (AGN). The observations performed from 2008 August 1 to 2011 December 31 confirmed that PMN J0948 + 0022 generates a powerful relativistic jet, which is able to develop an isotropic luminosity at γ-rays of the order of 1048 erg s-1, at the level ofpowerful quasars. The evolution of the radiation emission of this source in 2009 and 2010 followed the canonical expectations of relativistic jets with correlated multiwavelength variability (γ-rays followed by radio emission after a few months), but it was difficult to retrieve a similar pattern in the light curves of 2011. The comparison of γ-ray spectra before and including 2011 data suggested that there was a softening of the high-energy spectral slope. We selected five specific epochs to be studied by modelling the broad-band spectrum, which are characterised by an outburst at γ-rays or very low/high flux at other wavelengths. The observed variability can largely be explained by changes in the injected power, the bulk Lorentz factor of the jet, or the electron spectrum. The characteristic time scale of doubling/halving flux ranges from a few days to a few months, depending on the frequency and the sampling rate. The shortest doubling time scale at γ-rays is 2.3 ± 0.5 days. These small values underline the need of highly sampled multiwavelength campaigns to better understand the physics of these sources. Appendix A is available in electronic form at http://www.aanda.orgData displayed in Figs. A.1-A.3 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc

  1. THE RISE OF AN IONIZED WIND IN THE NARROW-LINE SEYFERT 1 GALAXY Mrk 335 OBSERVED BY XMM-NEWTON AND HST

    SciTech Connect

    Longinotti, A. L.; Krongold, Y.; Kriss, G. A.; Ely, J.; Gallo, L.; Grupe, D.; Komossa, S.; Mathur, S.; Pradhan, A.

    2013-04-01

    We present the discovery of an outflowing ionized wind in the Seyfert 1 galaxy Mrk 335. Despite having been extensively observed by most of the largest X-ray observatories in the last decade, this bright source was not known to host warm absorber gas until recent XMM-Newton observations in combination with a long-term Swift monitoring program have shown extreme flux and spectral variability. High-resolution spectra obtained by the XMM-Newton Reflection Grating Spectrometer (RGS) detector reveal that the wind consists of three distinct ionization components, all outflowing at a velocity of {approx}5000 km s{sup -1}. This wind is clearly revealed when the source is observed at an intermediate flux state (2-5 Multiplication-Sign 10{sup -12} erg cm{sup -2} s{sup -1}). The analysis of multi-epoch RGS spectra allowed us to compare the absorber properties at three very different flux states of the source. No correlation between the warm absorber variability and the X-ray flux has been determined. The two higher ionization components of the gas (log {xi} {approx} 2.3 and 3.3) may be consistent with photoionization equilibrium, but we can exclude this for the only ionization component that is consistently present in all flux states (log {xi} {approx} 1.8). We have included archival, non-simultaneous UV data from Hubble Space Telescope (FOS, STIS, COS) with the aim of searching for any signature of absorption in this source that so far was known for being absorption-free in the UV band. In the Cosmic Origins Spectrograph (COS) spectra obtained a few months after the X-ray observations, we found broad absorption in C IV lines intrinsic to the active galactic nucleus and blueshifted by a velocity roughly comparable to the X-ray outflow. The global behavior of the gas in both bands can be explained by variation of the covering factor and/or column density, possibly due to transverse motion of absorbing clouds moving out of the line of sight at broad line region scale.

  2. Simultaneous XMM-Newton and HST-COS observation of 1H 0419-577. II. Broadband spectral modeling of a variable Seyfert galaxy

    NASA Astrophysics Data System (ADS)

    Di Gesu, L.; Costantini, E.; Piconcelli, E.; Ebrero, J.; Mehdipour, M.; Kaastra, J. S.

    2014-03-01

    In this paper, we present the longest exposed (97 ks) XMM-Newton EPIC-pn spectrum ever obtained for the Seyfert 1.5 galaxy1H 0419-577. With the aim of explaining the broadband emission of this source, we took advantage of the simultaneous coverage in the optical/UV that was provided in the present case by the XMM-Newton Optical Monitor and by a HST-COS observation. Archival FUSE flux measurements in the far-ultraviolet were also used for the present analysis. We successfully modeled the X-ray spectrum and the optical/UV fluxes data points using a Comptonization model. We found that a blackbody temperature of T ~ 56 eV accounts for the optical/UV emission originating in the accretion disk. This temperature serves as an input for the Comptonized components that model the X-ray continuum. Both a warm (Twc ~ 0.7 keV, τwc ~ 7) and a hot corona (Thc ~ 160 keV, τhc ~ 0.5) intervene to upscatter the disk photons to X-ray wavelengths. With the addition of a partially covering (Cv ~ 50%) cold absorber with a variable opacity ( NH~ [1019-1022] cm-2), this model can also explain the historical spectral variability of this source, with the present dataset presenting the lowest one ( NH~1019 cm-2). We discuss a scenario where the variable absorber becomes less opaque in the highest flux states because it gets ionized in response to the variations of the X-ray continuum. The lower limit for the absorber density derived in this scenario is typical for the broad line region clouds. We infer that1H 0419-577may be viewed from an intermediate inclination angle i ≥ 54°, and, on this basis, we speculate that the X-ray obscuration may be associated with the innermost dust-free region of the obscuring torus. Finally, we critically compare this scenario with all the different models (e.g., disk reflection) that have been used in the past to explain the variability of this source.

  3. The NASA Spitzer Space Telescope.

    PubMed

    Gehrz, R D; Roellig, T L; Werner, M W; Fazio, G G; Houck, J R; Low, F J; Rieke, G H; Soifer, B T; Levine, D A; Romana, E A

    2007-01-01

    The National Aeronautics and Space Administration's Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991-2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer's expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/. PMID:17503900

  4. Finding η Car Analogs in Nearby Galaxies Using Spitzer. II. Identification of An Emerging Class of Extragalactic Self-Obscured Stars

    NASA Astrophysics Data System (ADS)

    Khan, Rubab; Kochanek, C. S.; Stanek, K. Z.; Gerke, Jill

    2015-02-01

    Understanding the late-stage evolution of the most massive stars such as η Carinae is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. In Khan et al., we utilized Spitzer IRAC images of 7 nearby (lsim 4 Mpc) galaxies to search for such analogs, and found 34 candidates with flat or red mid-IR spectral energy distributions. Here, in Paper II, we present our characterization of these candidates using multi-wavelength data from the optical through the far-IR. Our search detected no true analogs of η Car, which implies an eruption rate that is a fraction 0.01 <~ F <~ 0.19 of the core-collapse supernova (ccSN) rate. This is roughly consistent with each M ZAMS >~ 70 M ⊙ star undergoing one or two outbursts in its lifetime. However, we do identify a significant population of 18 lower luminosity (log (L/L ⊙) ~= 5.5-6.0) dusty stars. Stars enter this phase at a rate that is a fraction 0.09 <~ F <~ 0.55 of the ccSN rate, and this is consistent with all 25 < M ZAMS < 60 M ⊙ stars undergoing an obscured phase at most lasting a few thousand years once or twice. These phases constitute a negligible fraction of post-main-sequence lifetimes of massive stars, which implies that these events are likely to be associated with special periods in the evolution of the stars. The mass of the obscuring material is of order ~M ⊙, and we simply do not find enough heavily obscured stars for theses phases to represent more than a modest fraction (~10% not ~50%) of the total mass lost by these stars. In the long term, the sources that we identified will be prime candidates for detailed physical analysis with the James Webb Space Telescope.

  5. Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra

    NASA Astrophysics Data System (ADS)

    Thompson, Grant D.; Levenson, N. A.; Sirocky, M. M.; Uddin, S.

    2007-12-01

    Silicate dust emission dominates the mid-infrared spectra of galaxies, and the dust produces two spectral features, at 10 and 18 μm. These features' strengths (in emission or absorption) and peak wavelengths reveal the geometry of the dust distribution, and they are sensitive to the dust composition. We examine mid-infrared spectra of 32 Seyfert 1 active galactic nuclei (AGN), observed with the Infrared Spectrograph aboard the Spitzer Space Telescope. In the spectra, we typically find the shorter-wavelength feature in emission, at an average peak wavelength of 10.0 μm, although it is known historically as the "9.7 μm" feature. In addition, peak wavelength increases with feature strength. The 10 and 18 μm feature strengths together are sensitive to the dust geometry surrounding the central heating engine. Numerical calculations of radiative transfer distinguish between clumpy and smooth distributions, and we find that the surroundings of these AGN (the obscuring "tori" of unified AGN schemes) are clumpy. Polycyclic aromatic hydrocarbon (PAH) features are associated with star formation, and we find strong PAH emission (luminosity ≥ 1042 erg/s) in only four sources, three of which show independent evidence for starbursts. We will explore the effects of luminosity on dust geometry and chemistry in a comparison sample of quasars. We acknowledge work supported by the NSF under grant number 0237291.

  6. 22 GHz water maser search in 37 nearby galaxies. Four new water megamasers in Seyfert 2 and OH maser/absorber galaxies

    NASA Astrophysics Data System (ADS)

    Wagner, J.

    2013-12-01

    Aims: We report four new 22 GHz H2O water masers found in a Green Bank Telescope search toward 37 nearby objects. Our goal was to find new maser galaxies, active galactic nucleus (AGN) disk masers, and objects where hydroxyl and water maser species coexist. Methods: We observed 37 sources within 250 Mpc that were selected by high X-ray luminosity (LX > 1040 W) and high absorbing column density (NH ≳ 1022 cm-2). Sources included dual or triple AGN and interacting systems. We also searched objects detected in hydroxyl (OH). A catalog of 4038 known H2O (non)detections was assembled to avoid unnecessary reobservations. The final selection consisted of 16 new sources, 13 nondetections to follow up with a factor 10 higher sensitivity, 10 OH masers and 1 deep OH absorber, of which 37 were observed. Results: Water megamasers were detected towards the Sy 2 galaxy 2MFGC 13581, towards the 6 GHz OH absorber NGC 4261 and towards the two 1.6 GHz OH maser sources IRAS 17526+3253 and IRAS 20550+1656. We set upper limits on 33 nondetections. The detection rate was 25% in OH galaxies and 11% overall. The mean sensitivity was 4 mJy over 24.4 kHz (0.31 km s-1) or between 0.1 L⊙ and 1.0 L⊙ rms for the distances covered by the source sample. Combined with other searches, a total of 95 objects have now been searched for both OH and H2O masers. Conclusions: The maser features in 2MFGC 13581 are typical of a sub-parsec accretion disk, whereas NGC 4261 likely has jet masers in a masing torus. The NGC 4261 galaxy (3C 270; dusty torus, twin jet) and its masers appear similar to NGC 1052, where continuum seed emission by a twin jet supports masers in the torus. Imaging with very long baseline interferometry is required to determine the masing regions in NGC 4261 and 2MFGC 13581. IRAS 17526+3253 has narrow 350 L⊙ systemic masers, and the tentative 5σ detection in IRAS 20550+1656 (II Zw 96) strongly resembles massive star formation kilomasers in NGC 2146. The latter two detections

  7. Spitzer mid-IR spectroscopy of powerful 2Jy and 3CRR radio galaxies. II. AGN power indicators and unification

    SciTech Connect

    Dicken, D.; Tadhunter, C.; Morganti, R.; Axon, D.; Robinson, A.; Magagnoli, M.; Kharb, P.; Ramos Almeida, C.; Hardcastle, M.; Nesvadba, N. P. H.; Singh, V.; Kouwenhoven, M. B. N.; Rose, M.; Spoon, H.; Inskip, K. J.; Holt, J.

    2014-06-20

    It remains uncertain which continuum and emission line diagnostics best indicate the bolometric powers of active galactic nuclei (AGNs), especially given the attenuation caused by the circumnuclear material and the possible contamination by components related to star formation. Here we use mid-IR spectra along with multiwavelength data to investigate the merit of various diagnostics of AGN radiative power, including the mid-IR [Ne III] λ25.89 μm and [O IV] λ25.89 μm fine-structure lines, the optical [O III] λ5007 forbidden line, and mid-IR 24 μm, 5 GHz radio, and X-ray continuum emission, for complete samples of 46 2Jy radio galaxies (0.05 < z < 0.7) and 17 3CRR FRII radio galaxies (z < 0.1). We find that the mid-IR [O IV] line is the most reliable indicator of AGN power for powerful radio-loud AGNs. By assuming that the [O IV] is emitted isotropically, and comparing the [O III] and 24 μm luminosities of the broad- and narrow-line AGNs in our samples at fixed [O IV] luminosity, we show that the [O III] and 24 μm emission are both mildly attenuated in the narrow-line compared to the broad-line objects by a factor of ≈2. However, despite this attenuation, the [O III] and 24 μm luminosities are better AGN power indicators for our sample than either the 5 GHz radio or the X-ray continuum luminosities. We also detect the mid-IR 9.7 μm silicate feature in the spectra of many objects but not ubiquitously: at least 40% of the sample shows no clear evidence for these features. We conclude that, for the majority of powerful radio galaxies, the mid-IR lines are powered by AGN photoionization.

  8. ON THE ORIGIN OF LOPSIDEDNESS IN GALAXIES AS DETERMINED FROM THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

    SciTech Connect

    Zaritsky, Dennis; Hinz, Joannah L.; Salo, Heikki; Laurikainen, Eija; Comeron, Sebastien; Laine, Jarkko; Elmegreen, Debra; Athanassoula, E.; Bosma, Albert; Erroz-Ferrer, Santiago; Knapen, Johan H.; Elmegreen, Bruce; Gadotti, Dimitri A.; Kim, Taehyun; De Paz, Armando Gil; Ho, Luis C.; Madore, Barry F.; Holwerda, Benne W.; Laine, Seppo; Meidt, Sharon; and others

    2013-08-01

    We study the m = 1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not correlated with the presence or absence of a bar, or the strength of the bar when one is present, (3) is inversely correlated to the stellar mass fraction, f{sub *}, within one radial scale length, and (4) correlates directly with f{sub *} measured within the radial range over which we measure lopsidedness. We interpret these findings to mean that lopsidedness is a generic feature of galaxies and does not, generally, depend on a rare event, such as a direct accretion of a satellite galaxy onto the disk of the parent galaxy. While lopsidedness may be caused by several phenomena, moderate lopsidedness ((A{sub 1}){sub i} + (A{sub 1}){sub o})/2 < 0.3) is likely to reflect halo asymmetries to which the disk responds or a gravitationally self-generated mode. We hypothesize that the magnitude of the stellar response depends both on how centrally concentrated the stars are with respect to the dark matter and whether there are enough stars in the region of the lopsidedness that self-gravity is dynamically important.

  9. LOCAL LUMINOUS INFRARED GALAXIES. III. CO-EVOLUTION OF BLACK HOLE GROWTH AND STAR FORMATION ACTIVITY?

    SciTech Connect

    Alonso-Herrero, Almudena; Hernan-Caballero, Antonio; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang Yiping; Rigopoulou, Dimitra

    2013-03-10

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 Multiplication-Sign 10{sup 7} M{sub Sun} using [Ne III] 15.56 {mu}m and optical [O III] {lambda}5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear {approx}1.5 kpc region, as estimated from the nuclear 11.3 {mu}m PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy.

  10. Crashing galaxies, cosmic fireworks

    SciTech Connect

    Keel, W.C.

    1989-01-01

    The study of binary systems is reviewed. The history of the study of interacting galaxies, the behavior of gas in binary systems, studies to identify the processes that occur when galaxies interact, and the relationship of Seyfert galaxies and quasars to binary systems are discussed. The development of an atlas of peculiar galaxies (Arp, 1966) and methods for modeling galaxy interactions are examined.

  11. Precision Fe K-Alpha and Fe K-Beta Line Spectroscopy of the Seyfert 1.9 Galaxy NGC 2992 with Suzaku

    NASA Technical Reports Server (NTRS)

    Yaqoob, Tahir; Murphy, Kendrah D.; Griffiths, Richard E.; Haba, Yoshito; Inoue, Hajime; Itoh, Takeshi; Kelley, Richard; Kokubun, Motohide; Markowitz, Alex; Mushotzky, Richard; Okajima, Takashi; Ptak, Andrew; Reeves, James; Selemitos, Peter J.; Takahashi, Tadayuki; Terashima, Yuichi

    2006-01-01

    We present detailed time-averaged X-ray spectroscopy in the 0.5-10 keV band of the Seyfert 1.9 galaxy NGC 2992 with the Suzaku X-ray Imaging Spectrometers (XIS). The source had a factor approximately 3 higher 2-10 keV flux (approximately 1.2 x l0(exp -11) erg per square cm per s) than the historical minimum and a factor approximately 7 less than the historical maximum. The XIS spectrum of NGC 2992 can be described by several components. There is a primary continuum, modeled as a power-law with a photon index of Gamma = 1.57(sup +0.06) (sup -0.03) that is obscured by a Compton-thin absorber with a column density of 8.01(sup +0.6) (sup -0.5)x l0 (exp 21) per square cm. . There is another, weaker, unabsorbed power-law component (modeled with the same slope as the primary), that is likely to be due to the primary continuum being electron-scattered into our line-of-sight by a region extended on a scale of hundreds of parsecs. We measure the Thomson depth of the scattering zone to be Tau = 0.072 +/- 0.021. An optically-thin thermal continuum emission component, which probably originates in the same extended region, is included in the model and yields a temperature and luminosity of KT = 0.656(sup +0.088) (sup -0.0.61) keV and approximately 1.2 +/- 0.4 x l0 (exp 40) erg per s respectively. We detect an Fe K emission complex which we model with broad and narrow lines and we show that the intensities of the two components are decoupled at a confidence level > 3 sigma. The broad Fe K alpha line has an equivalent width of 118(sup +32) (sup -61) eV and could originate in an accretion disk (with inclination angle greater than approximately 30 deg) around the putative central black hole. The narrow Fe K alpha line has an equivalent width of 1632(sup +47) (sup -26) eV and is unresolved (FWHM < 4630 km per s) and likely originates in distant matter. The absolute flux in the narrow line implies that the column density out of the line-of-sight could be much higher than measured in

  12. The mass function of Seyfert 1 nuclei

    NASA Technical Reports Server (NTRS)

    Padovani, P.; Burg, R.; Edelson, R. A.

    1990-01-01

    The first mass function of Seyfert 1 nuclei is derived from optical spectra of the complete CfA sample of Seyfert galaxies by estimating the mass for each object from a dynamical relation. An independent estimate is also derived using a complete infrared-selected sample. The two mass functions are indistinguishable. The mean mass of Seyfert 1 nuclei is about 2 x 10 to the 7th solar masses, and the integrated mass density is about 6 x 10 to the 11th solar masses/cu Gpc. This is approximately two orders of magnitude less than the value inferred from the energetics associated with quasar counts. A careful analysis of the various parameters and assumptions involved suggests that this large difference is not due to systematic errors in the determinations. Therefore, the bulk of mass related to the accretion processes connected with past quasar activity does not reside in Seyfert 1 nuclei. Instead, the remnants of past activity must be present in a much larger number of galaxies, and a one-to-one relation between distant and local active galactic nuclei seems then to be excluded.

  13. Warm absorbers in X-rays (WAX), a comprehensive high-resolution grating spectral study of a sample of Seyfert galaxies - I. A global view and frequency of occurrence of warm absorbers.

    NASA Astrophysics Data System (ADS)

    Laha, Sibasish; Guainazzi, Matteo; Dewangan, Gulab C.; Chakravorty, Susmita; Kembhavi, Ajit K.

    2014-07-01

    We present results from a homogeneous analysis of the broad-band 0.3-10 keV CCD resolution as well as of the soft X-ray high-resolution grating spectra of a hard X-ray flux-limited sample of 26 Seyfert galaxies observed with XMM-Newton. Our goal is to characterize warm absorbers (WAs) along the line of sight to the active nucleus. We significantly detect WAs in 65 per cent of the sample sources. Our results are consistent with WAs being present in at least half of the Seyfert galaxies in the nearby Universe, in agreement with previous estimates. We find a gap in the distribution of the ionization parameter in the range 0.5 < log ξ < 1.5 which we interpret as a thermally unstable region for WA clouds. This may indicate that the WA flow is probably constituted by a clumpy distribution of discrete clouds rather than a continuous medium. The distribution of the WA column densities for the sources with broad Fe Kα lines are similar to those sources which do not have broadened emission lines. Therefore, the detected broad Fe Kα emission lines are bona fide and not artefacts of ionized absorption in the soft X-rays. The WA parameters show no correlation among themselves, with the exception of the ionization parameter versus column density. The shallow slope of the log ξ versus log vout linear regression (0.12 ± 0.03) is inconsistent with the scaling laws predicted by radiation or magnetohydrodynamic-driven winds. Our results also suggest that WA and ultra fast outflows do not represent extreme manifestation of the same astrophysical system.

  14. Education with Infrared Astronomy and Spitzer

    NASA Astrophysics Data System (ADS)

    Hemphill, Rosa; Blackwell, J. A.; Herrold, A.; Petroff, E.

    2007-12-01

    We present education and outreach results using our experiences involving the Spitzer Space Telescope project, Star Formation in High Redshift Clusters with Spitzer. The project is a collaboration between the Spitzer Science Center and the National Optical Astronomy Observatory. Using the Spitzer Space Telescope, we measured star formation rates in three galaxy clusters at intermediate redshifts. Six teachers were chosen for the program, each with an interest and involvement in astronomy education. From this project, lesson plans, public outreach, lectures and demonstrations were generated which better the understanding of infrared astronomy, multiwavelength astronomy, galaxy and star formation, and cosmology. The teacher mentors are Dr. Gregory Rudnick (NOAO), Dr. Rose Finn (Siena College), and Dr. Vandana Desai (Caltech). Please see the companion posters by Emily Petroff, Zak Schroeder, and Thomas Loughran, et al, for information concerning the science results.

  15. FINDING η CAR ANALOGS IN NEARBY GALAXIES USING Spitzer. II. IDENTIFICATION OF AN EMERGING CLASS OF EXTRAGALACTIC SELF-OBSCURED STARS

    SciTech Connect

    Khan, Rubab; Kochanek, C. S.; Stanek, K. Z.; Gerke, Jill

    2015-02-01

    Understanding the late-stage evolution of the most massive stars such as η Carinae is challenging because no true analogs of η Car have been clearly identified in the Milky Way or other galaxies. In Khan et al., we utilized Spitzer IRAC images of 7 nearby (≲ 4 Mpc) galaxies to search for such analogs, and found 34 candidates with flat or red mid-IR spectral energy distributions. Here, in Paper II, we present our characterization of these candidates using multi-wavelength data from the optical through the far-IR. Our search detected no true analogs of η Car, which implies an eruption rate that is a fraction 0.01 ≲ F ≲ 0.19 of the core-collapse supernova (ccSN) rate. This is roughly consistent with each M {sub ZAMS} ≳ 70 M {sub ☉} star undergoing one or two outbursts in its lifetime. However, we do identify a significant population of 18 lower luminosity (log (L/L {sub ☉}) ≅ 5.5-6.0) dusty stars. Stars enter this phase at a rate that is a fraction 0.09 ≲ F ≲ 0.55 of the ccSN rate, and this is consistent with all 25 < M {sub ZAMS} < 60 M {sub ☉} stars undergoing an obscured phase at most lasting a few thousand years once or twice. These phases constitute a negligible fraction of post-main-sequence lifetimes of massive stars, which implies that these events are likely to be associated with special periods in the evolution of the stars. The mass of the obscuring material is of order ∼M {sub ☉}, and we simply do not find enough heavily obscured stars for theses phases to represent more than a modest fraction (∼10% not ∼50%) of the total mass lost by these stars. In the long term, the sources that we identified will be prime candidates for detailed physical analysis with the James Webb Space Telescope.

  16. Seyfert Spectral Database: 10 Years Of Rxte Observations

    NASA Astrophysics Data System (ADS)

    Mattson, Barbara; Weaver, K.; Reynolds, C.

    2008-05-01

    What does the core of an active galactic nucleus truly look like? Do all Seyfert 2s have a Seyfert 1 at their core? How does the environment of their central regions affect our view of the central engine? We explore these questions with a systematic X-ray spectral study of bright Seyfert galaxies observed by the Rossi X-Ray Timing Explorer (RXTE). We develop a database of spectral fits of 821 time-resolved spectra from 39 Seyfert galaxies fitted to a standard model including the effects of a power-law X-ray spectrum reprocessed and absorbed by material around the black hole. We find a complex relationship between the iron line equivalent width (EW) and the underlying power law index (Γ) in the Seyfert 1 sample, which may be caused by dilution of a disk spectrum (which includes the narrow iron line) by a beamed jet component and, hence, could be used as a diagnostic of jet-dominance. The same relationship does not hold for the Seyfert 2 sample, and may indicate that these sources show more complex environments. We also see the X-ray Baldwin effect (an anti-correlation between the 2-10 keV X-ray luminosity and EW) for the Seyfert 1 sample and Seyfert 1 sub-classifications, but not for each individual galaxy. In addition, our sample shows a strong correlation between R and Γ for all spectra in the sample, but we find that it is likely the result of a modeling degeneracy.

  17. THE SPECTRAL ENERGY DISTRIBUTIONS AND INFRARED LUMINOSITIES OF z Almost-Equal-To 2 DUST-OBSCURED GALAXIES FROM Herschel AND Spitzer

    SciTech Connect

    Melbourne, J.; Soifer, B. T.; Desai, Vandana; Armus, Lee; Pope, Alexandra; Alberts, Stacey; Dey, Arjun; Jannuzi, B. T.; Bussmann, R. S. E-mail: bts@submm.caltech.edu E-mail: lee@ipac.caltech.edu E-mail: pope@astro.umass.edu E-mail: jannuzi@noao.edu

    2012-05-15

    Dust-obscured galaxies (DOGs) are a subset of high-redshift (z Almost-Equal-To 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L{sub IR} > 10{sup 12} L{sub Sun} ). We present new far-infrared photometry, at 250, 350, and 500 {mu}m (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10{sup 11.6} L{sub Sun} 10{sup 13} L{sub Sun }. The rest-frame near-IR (1-3 {mu}m) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with 'power-law' SEDs in the rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar 'bump' in their rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 {mu}m flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 {mu}m flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within {approx}25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 {mu}m luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 {mu}m luminosity (the IR8 = L{sub IR}(8-1000 {mu}m)/{nu}L{sub {nu}}(8 {mu}m) parameter of Elbaz et al.). Instead of lying on the z = 1-2 'infrared main sequence' of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of

  18. Multiwavelength Search and Studies of Active Galaxies

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.

    2016-06-01

    Since 1950s, Byurakan Astrophysical Observatory (BAO) has always been one of the centres for surveys and studies of active galaxies. Here I review our search and studies of active galaxies during last 30 years using various wavelength ranges, as well as some recent related works. These projects since late 1980s were focused on multiwavelength search and studies of AGN and Starbursts (SB). 1103 blue stellar objects (BSOs) on the basis of their UV-excess were selected using Markarian Survey (First Byurakan Survey, FBS) plates and Markarian's criteria used for the galaxies. Among many blue stars, QSOs and Seyfert galaxies were found by follow-up observations. 1577 IRAS point sources were optically identified using FBS low-dispersion spectra and many AGN, SB and high-luminosity IR galaxies (LIRG/ULIRG) were discovered. 32 extremely high IR/opt flux ratio galaxies were studies with Spitzer. 2791 ROSAT FSC sources were optically identified using Hamburg Quasar Survey (HQS) low-dispersion spectra and many AGN were discovered by follow-up observations. Fine analysis of emission line spectra was carried out using spectral line decomposition software to establish true profiles and calc