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Sample records for obscured seyfert galaxy

  1. Reflection in obscured Seyfert galaxies and the CXB

    NASA Astrophysics Data System (ADS)

    Walter, Roland; Esposito, Valentino

    2015-08-01

    We present a study of the average hard X-ray spectra of Seyfert galaxies of different types obtained accumulating one billion seconds of Swift/BAT data and reaching a sensitivity of 20 micro-Crab in the hard X-rays. The resulting spectra are representative of the average emission of these objects (in the local Universe) and can be used as a template for the synthesis of the Cosmic X-ray Background.The ratio of the average spectra obtained for Compton-thin obscured and unobscured sources, derived with high accuracy, is characteristic of a reflection hump and confirms that midly obsured and Compton thin Seyfert 2 galaxies feature much more reflection than unabsorbed sources.This large reflection cannot be explained easily by the unified model and points towards the clumpy torus model. It also provides a natural explanation for the peak, intensity and spectral shape of the Cosmic X-ray Background without requiring a large population of Compton thick sources.

  2. X-Ray Spectral Properties of Seven Heavily Obscured Seyfert 2 Galaxies

    NASA Astrophysics Data System (ADS)

    Marchesi, S.; Ajello, M.; Comastri, A.; Cusumano, G.; La Parola, V.; Segreto, A.

    2017-02-01

    We present the combined Chandra and Swift-BAT spectral analysis of seven Seyfert 2 galaxies selected from the Swift-BAT 100 month catalog. We selected nearby (z ≤ 0.03) sources lacking a ROSAT counterpart that never previously been observed with Chandra in the 0.3–10 keV energy range, and targeted these objects with 10 ks Chandra ACIS-S observations. The X-ray spectral fitting over the 0.3–150 keV energy range allows us to determine that all the objects are significantly obscured, with N H ≥ 1023 cm‑2 at a >99% confidence level. Moreover, one to three sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs; i.e., N H ≥ 1024 cm‑2). We also test the recent spectral curvature method developed by Koss et al. to find candidate CT-AGNs, finding a good agreement between our results and their predictions. Because the selection criteria we adopted were effective in detecting highly obscured AGNs, further observations of these and other Seyfert 2 galaxies selected from the Swift-BAT 100 month catalog will allow us to create a statistically significant sample of highly obscured AGNs, therefore providing a better understanding of the physics of the obscuration processes.

  3. On the relation of optical obscuration and X-ray absorption in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Burtscher, L.; Davies, R. I.; Graciá-Carpio, J.; Koss, M. J.; Lin, M.-Y.; Lutz, D.; Nandra, P.; Netzer, H.; Orban de Xivry, G.; Ricci, C.; Rosario, D. J.; Veilleux, S.; Contursi, A.; Genzel, R.; Schnorr-Müller, A.; Sternberg, A.; Sturm, E.; Tacconi, L. J.

    2016-02-01

    The optical classification of a Seyfert galaxy and whether it is considered X-ray absorbed are often used interchangeably. There are many borderline cases, however, and also numerous examples where the optical and X-ray classifications appear to be in disagreement. In this article we revisit the relation between optical obscuration and X-ray absorption in active galactic nuclei (AGNs). We make use of our "dust colour" method to derive the optical obscuration AV, and consistently estimated X-ray absorbing columns using 0.3-150 keV spectral energy distributions. We also take into account the variable nature of the neutral gas column NH and derive the Seyfert subclasses of all our objects in a consistent way. We show in a sample of 25 local, hard-X-ray detected Seyfert galaxies (log LX/ (erg / s) ≈ 41.5-43.5) that there can actually be a good agreement between optical and X-ray classification. If Seyfert types 1.8 and 1.9 are considered unobscured, the threshold between X-ray unabsorbed and absorbed should be chosen at a column NH = 1022.3 cm-2 to be consistent with the optical classification. We find that NH is related to AV and that the NH/AV ratio is approximately Galactic or higher in all sources, as indicated previously. However, in several objects we also see that deviations from the Galactic ratio are only due to a variable X-ray column, showing that (1) deviations from the Galactic NH/AV can be simply explained by dust-free neutral gas within the broad-line region in some sources; that (2) the dust properties in AGNs can be similar to Galactic dust and that (3) the dust colour method is a robust way to estimate the optical extinction towards the sublimation radius in all but the most obscured AGNs.

  4. Ginga observations of Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Awaki, H.; Koyama, K.

    1993-01-01

    We observed twenty-eight Seyfert 2 galaxies with the Japanese X-ray satellite, Ginga, and found Seyfert 2 galaxies, in general, have the X-ray spectral characteristics of obscured Seyfert 1 nuclei. This results agrees with the predictions from the Unified Seyfert model proposed by Antonucci and Miller. However, among the observed Seyfert 2 galaxies, there are a few galaxies with no evidence of an obscuration, contrary to the general predictions of the unified model. We note that type 2 active galactic nuclei (AGN) will contribute to the Cosmic Diffuse X-ray Background, if the unified Seyfert model can be extended to the far distant AGN such as quasars.

  5. Chandra Reveals Heavy Obscuration and Circumnuclear Star Formation in Seyfert 2 Galaxy NGC 4968

    NASA Astrophysics Data System (ADS)

    LaMassa, Stephanie M.; Yaqoob, Tahir; Levenson, N. A.; Boorman, Peter; Heckman, Timothy M.; Gandhi, Poshak; Rigby, Jane R.; Urry, C. Megan; Ptak, Andrew F.

    2017-01-01

    We present the Chandra imaging and spectral analysis of NGC 4968, a nearby (z = 0.00986) Seyfert 2 galaxy. We discover extended (∼1 kpc) X-ray emission in the soft band (0.5–2 keV) that is neither coincident with the narrow line region nor the extended radio emission. Based on spectral modeling, it is linked to on-going star formation (∼2.6–4 M⊙ yr‑1). The soft emission at circumnuclear scales (inner ∼400 pc) originates from hot gas, with kT ∼ 0.7 keV, while the most extended thermal emission is cooler (kT ∼ 0.3 keV). We refine previous measurements of the extreme Fe Kα equivalent width in this source ({EW}={2.5}-1.0+2.6 {keV}), which suggests the central engine is completely embedded within Compton-thick levels of obscuration. Using physically motivated models fit to the Chandra spectrum, we derive a Compton-thick column density (NH > 1.25 × 1024 cm‑2) and an intrinsic hard (2–10 keV) X-ray luminosity of ∼3–8 × 1042 erg s‑1 (depending on the presumed geometry of the obscurer), which is over two orders of magnitude larger than that observed. The large Fe Kα EW suggests a spherical covering geometry, which could be confirmed with X-ray measurements above 10 keV. NGC 4968 is similar to other active galaxies that exhibit extreme Fe Kα EWs (i.e., >2 keV) in that they also contain on-going star formation. This work supports the idea that gas associated with nuclear star formation may increase the covering factor of the enshrouding gas and play a role in obscuring active galactic nuclei.

  6. 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.

  7. Multi-wavelength Probes of Obscuration Towards the Narrow Line Region in Seyfert Galaxies (PREPRINT)

    DTIC Science & Technology

    2010-11-01

    in the Seyfert 1 galaxy NGC 4151 (Kraemer et al. 2000), near IR emission detected in Gemini/Near-Infrared Integrated Field Spectrograph ( NIFS ...any case, it points to the presence of a significant amount of material outside the optical NLR, in agreement with results from NIFS spectra of a

  8. 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.

  9. 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.

  10. 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.

  11. IRAS observations of Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Miley, G. K.; Neugebauer, G.; Soifer, B. T.

    1985-01-01

    Infrared Astronomy Satellite measurements at 25, 60 and 100 microns were used to analyze the infrared properties of Seyfert galaxies from the Markarian and NGC Catalogs. One hundred and sixteen of 186 Seyfert galaxies were detected. About 50% of all Seyfert galaxies in the sample have 60 micron luminosities in excess of 10 to the 10th power solar luminosity, and the mean 60 micron luminosity increase with the optical B absolute magnitude. The luminosity functions of the Seyfert 1 and Seyfert 2 galaxies appear quite similar. It is possible, however, to statistically separate the two types of galaxies in color-color plots. The 100- to 60- micron energy distributions flatten systematically with increasing 60- micron luminosity. The infrared measurements provide a measure of the bolometric luminosity of the Seyfert galaxies, but do not discriminate between the physical processes involved.

  12. Universal Scattering Property of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Hall, C. R.; Bruhweiler, F. C.; Madejski, G. M.

    1996-12-01

    The dusty torus model of Seyfert galaxies--the so-called Unified Model--(Antonucci & Miller 1985; Antonucci 1993) states that both type 1 and type 2 objects are intrinsically the same and share a similar overall geometry. Depending upon the observer's line of sight to the central engine, the broad lines which define the Seyfert type may be visible (Sy 1) or obscured by the torus (Sy 2), while the narrow lines are equally visible in both classes. In addition the polar regions of the torus contain an electron scattering atmosphere, extending beyond the polar openings. Via Thomson scattering of central engine photons, the broad line feature in Sy 2s can only be detected in polarized light. From an empirical analysis comparing the narrow Balmer H-beta observed in a sample of objects from both classes against the broad Balmer H-beta observed directly in Seyfert 1s, and observed in polarized light in Seyfert 2s, we find a general scattering law: the ratio of the intrinsic luminosity to the polarized luminosity in the line is approximately 300. This has strong implications on the geometry and physical properties of the scattering medium. References: Antonucci, R.R.J. 1993,ARA&A, 31, 473 Antonucci, R.R.J.,& Miller,J.S. 1985,ApJ, 297, 621

  13. UV Observations of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Boggess, Albert

    We propose to obtain high-quality, broadened (equivalent to trailed) spectra for 9 Type I and 2 Type 2 Seyfert galaxies. Only broadened spectra have sufficient signal-to-noise ratios to allow detailed fitting of line profiles needed to investigate both the kinematics and dynamics of the emitting regions and their stratification. These spectra will also allow more accurate measurements of weak spectral features, such as: OI 1304 and He II 1640, needed to estimate reddening; N IV] 1486, O III] 1663 and N III] 1749, for abundance analyses; absorption lines such as Si IV l400 and C IV 1550, for estimating the covering factor of the broad line region (BLR); and Galactic halo absorption lines of Si II 1260, C II 1335 and Fe II 1608. There are broad features superposed on the spectrum of Seyfert galaxies: the 2200A dust absorption feature, the emission hump at 3200A and several other unidentified bumps and wiggles. Their detection, measurement and quantitative study also require spectra recorded with high signal-to-noise ratios. X-ray spectra are already available for all 9 Type 1 Seyferts, and these data will be combined with our UV continua to estimate the amounts of available ionizing radiation. We also plan to measure the fluxes of the prominent emission lines: L-alpha, SI IV 1400, C IV 1550, C III] 1900 and Mg II 2800, to extend our investigation of the L-alpha/H-beta ratio and to provide a homogeneous set of high quality data to allow the evaluation of models for individual objects instead of, as in the past, for an assumed "typical" Seyfert or quasar.

  14. Circumnuclear Star Formation in Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Marquette, Melissa; Hicks, Erin K.; Mueller Sanchez, Francisco; Malkan, Matthew Arnold; Davies, Richard

    2017-01-01

    We examine a group of Seyfert 1 and Seyfert 2 galaxies to determine whether there exists a correlation between the circumnuclear starburst age and the luminosity of the active galactic nucleus. Using data from the Keck OSIRIS Nearby AGN (KONA) survey, we have a sample size of 40 Seyfert galaxies (split between Seyfert 1s and 2s), in which we measure the circumnuclear properties down to a few tens of parsecs. We determine the age of the most recent episode of circumnuclear star formation by analyzing the equivalent width of the Br Gamma 2.16 micron emission line and further constrain the age using measurements of the K-band mass to light ratio. The results of these analyses will be presented, including a comparison of the Seyfert 1 and Seyfert 2 subsamples.

  15. A Robust Test of the Unified Model for Seyfert Galaxies with Implications for the Starburst Phenomenon

    NASA Technical Reports Server (NTRS)

    Weaver, Kimberly A.

    1997-01-01

    My research involves detailed analysis of X-ray emission from Active Galactic Nuclei (AGN). For over a decade, the paradigm for AGN has rested soundly on the unified model hypothesis, which posits that the only difference between broad-line objects (e.g., Type 1 Seyfert galaxies) and narrow-line objects (e.g., Type 2 Seyferts) is that in the former case our line of sight evades toroidal obscuration surrounding the nucleus, while in the latter, our line of sight is blocked by the optically thick torus. It is well established that some Seyfert 2s contain Seyfert I nuclei (i.e., a hidden broad line region), but whether or not all Seyfert 2s contain obscured Seyfert 1 nuclei or whether some Seyfert 2s are intrinsically Seyfert 2s is not known. Optical, IR, and UV surveys are not appropriate to examine this hypothesis because such emissions are either anisotropic or subject to the effects of obscuration, and thus depend strongly on viewing angle. Hard X-rays, on the other hand, can penetrate gas with column densities as high as 10( exp 24.5) cm(-2) and thus provide reliable, direct probes of the cores of heavily obscured AGN. Combining NASA archival data from the Advanced Satellite of Cosmology and Astrophysics (ASCA), the Rossi X-ray Timing Explorer (RXTE), and Rosat, I am accumulating X-ray data between 0.1 and 60 keV to produce a catalog of the broad-band X-ray spectral properties of Seyfert galaxies. These data will be used to perform concrete tests of the unified model, and (compared with similar data on Starbursts) to examine a possible evolutionary connection between Seyfert and Starburst galaxies.

  16. Absorption-Line Studies of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Shull, J. Michael

    We propose to undertake a "reverberation analysis" of the variable absorption lines ill two Seyfert Galaxies (NGC 4051 and Mrk 279) to help understand the origin of intrinsic absorption lines in AGNs. Stich an analysis is a powerful tool for elucidating the radial distribution of absorbing gas in the broad-line region (BLR) and narrow-line region (NLR). Only two Seyferts have previously been studied with this technique: NGC 4151 (Bromage el al. 1985; Clavel et al. 1987) and NGC 3516 (Voit, Shull, and Begelman 1987). The absorption features have been interpreted as an outflow of ionized clouds from the nuclear region or from an accretion disk affected by UV/X-ray heating. Neither the source of the absorbing gas in these Seyferts nor the "gene" which distingishes them from other Seyferts is known. Until the 1984 onset of absorption in Mrk 279, broad self-absorbed. lines had been observed only in Seyferts of low intrinsic luminosity, such as NGC 4051. Mrk 279 is intrinsically much brighter, and therefore more quasar-like, than the other three absorptionline Seyfert I's in the CfA sample. Thus, it may show how the absorption phenomenon changes at higher luminosity and could bridge the gap between the low luminosity absorption-line Seyferts and the well-studied broad absorption-line (BAL) QSO's. In addition, Mrk 279's significant redshift will allow us to study, for the first time, the Ly-alpha line in an absorption-line Seyfert. With 3 US-1 shifts for each of these two underobserved Seyferts, we can double the number of objects in which absorption-line variability has been studied and investigate why the absorption-line strengths correlate or anti-correlate with the UV continuum.

  17. Superwinds in Seyfert Galaxies SFGs and AGN

    NASA Technical Reports Server (NTRS)

    Baum, Stefi

    1999-01-01

    This project was successfully completed; three refereed publications have been published on the work and the graduate student involved successfully defended his thesis. The work done in conjunction with this project demonstrated for the first time the importance of large scale winds in most if not all Seyfert galaxies and explored the physical parameters of those winds and their effect on both the interstellar medium of the host galaxy and the activity in the active nucleus as well.

  18. Black Hole Masses in Three Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Onken, C. A.; Peterson, B. M.; Dietrich, M.; Robinson, A.; Salamanca, I. M.

    2003-01-01

    We analyze published reverberation mapping data for three Seyfert galaxies (NGC 3227, NGC 3516, and NGC 4593) to refine the mass estimate for the supermassive black hole in the center of each object. Treatment of the data in a manner more consistent with other large compilations of such masses allows us to more securely compare our results to wider samples of data, e.g., in the investigation of the M(sub bh-sigma*) relationship for active and quiescent galaxies.

  19. X-ray Emission from Seyfert 2 Galaxies with Low-Mass Black Holes

    NASA Astrophysics Data System (ADS)

    Barth, Aaron

    2005-10-01

    We have recently identified the first sample of Seyfert 2 nuclei in host galaxies with stellar velocity dispersions smaller than 60 km/s, as a way to detect and study black holes with likely masses below 10^6 solar masses. These galaxies are Type 2 analogs of "dwarf" Seyfert 1 galaxies such as NGC 4395 and POX 52. We propose to obtain XMM exposures of four Seyfert 2 galaxies with stellar velocity dispersions in the range 25-47 km/s in order to (a) determine X-ray luminosities as part of an overall program to measure the SEDs of these sources; (b) determine the amount of X-ray absorption to establish whether these are obscured versions of NLS1 galaxies; (c) search for variability, which is expected for AGNs with very low black hole masses.

  20. Black Holes Masses in Seyfert Galaxies

    NASA Technical Reports Server (NTRS)

    Macchetto, F. D.

    2004-01-01

    There is increasing evidence for the existence of supermassive black holes at the centers of all galaxies, and much work is being devoted to understand the process that lead to their formation, the duty cycle for the active phase of these black holes and the relevant fueling mechanisms. Seyfert galaxies determined by HST high spatial resolution observations of the kinematics of the central regions. The study of the gas kinematics provides a unique tool to probe the gravitational potential of the nuclear regions of Seyfert galaxies down to a limit radius of a few parsecs. This is particularly important to detect and measure the mass associated with any central massive black hole. We have obtained high spatial resolution spectra of a number of Seyfert galaxies, with the STIS G430M and G750M gratings, and we have been able to separate the emission line components associated with different velocity systems. We have derived two-dimensional velocity fields and determined the mass of the central black hole with good precision for each of the galaxies.

  1. 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.

  2. 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.

  3. Dust obscuration by an evolving galaxy population

    NASA Technical Reports Server (NTRS)

    Najita, Joan; Silk, Joseph; Wachter, Kenneth W.

    1990-01-01

    The effect of an evolving luminosity function (LF) on the ability of foreground galaxies to obscure background sources is discussed, using the Press-Schechter/CDM standard evolving LF model. Galaxies are modeled as simplified versions of local spirals and Poisson statistics are used to estimate the fraction of sky covered by intervening dusty galaxies and the mean optical depths due to these galaxies. The results are compared to those obtained in the case of nonevolving luminosity function in a low-density universe. It is found that evolution of the galaxy LF does not allow the quasar dust obscuration hypothesis to be sustained for dust disks with plausible sizes. Even in a low-density universe, where evolution at z = less than 10 is unimportant, large disk radii are needed to achieve the desired obscuring effect. The mean fraction of sky covered is presented as a function of the redshift z along with adequate diagram illustrations.

  4. Markarian 348: a tidally disturbed seyfert galaxy.

    PubMed

    Simkin, S M; Su, H J; VAN Gorkom, J; Hibbard, J

    1987-03-13

    Combined optical and radio images of galaxies can provide new insights into the sizes, masses, and possible evolution of these objects. Deep optical and neutral hydrogen images of Markarian 348, a type 2 Seyfert galaxy, show that it is a gigantic spiral (perhaps the largest known non-cluster galaxy). Measurements of the neutral hydrogen velocity field and spiral structure, and detection of an optical "tidal plume," all provide evidence that it has been subject to tidal disruption. The measured velocities yield a mass-to-light ratio for this object (within a radius of 130 kiloparsecs from its nucleus) that is similar to the ratio found for the inner regions of most galaxies of similar type. This is one of the few cases where detailed velocity measurements have demonstrated that a galaxy with an active nucleus has been subject to extensive tidal perturbation.

  5. 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.

  6. Deficiency of "Thin" Stellar Bars in Seyfert Host Galaxies.

    PubMed

    Shlosman; Peletier; Knapen

    2000-06-01

    Using all available major samples of Seyfert galaxies and their corresponding closely matched control samples of nonactive galaxies, we find that the bar ellipticities (or axial ratios) in Seyfert galaxies are systematically different from those in nonactive galaxies. Overall, there is a deficiency of bars with large ellipticities (i.e., "thin" or "strong" bars) in Seyfert galaxies compared to nonactive 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, 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 nonactive counterparts on scales of a few kiloparsecs.

  7. Are there two populations of X-ray absorbers in Seyfert 2 galaxies?

    NASA Astrophysics Data System (ADS)

    Gelbord, J. M.; Weaver, K. A.

    1998-12-01

    The canonical unified model for Seyfert galaxies (Antonucci, 1993, ARA&A 31, 473) posits the existance of a nuclear torus which blocks the direct line of sight to the central engine of type 2 Seyferts. However, another possibility would be that in at least some Seyfert galaxies the obscuring body could be the disk of the host galaxy (Schmitt et al., 1997, ApJ 477, 623). The column densities of the putative tori should be a few orders of magnitude larger than those of the host galaxy planes, so we would expect a bimodal distribution of NH columns if either of these absorbers could be responsible. Starting with the subset of the Schmitt et al. sample for which ASCA data is available, we are measuring the NH column densities using a variety of spectral models. The resulting distribution of column densities is then interpreted with consideration of both optically observed galactic inclinations and possible nuclear torus orientations implied from observed radio elongation axes. This work is being done as a part of a thesis project to examine the emission and absorption features in the X-ray spectra of a large sample of Seyfert galaxies, and to combine this data with observations made in other wavebands in order to put constraints on the unified model of Seyfert galaxies.

  8. 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

  9. 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.

  10. The coronal parameters of local Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Marinucci, A.

    2015-07-01

    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 NuSTAR. The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing X-ray telescope on orbit, ˜ 100 times more sensitive in the 10-80 keV band compared to previous observatories, enabling the study of AGN at high energies with high precision. We will 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 or Suzaku) with unprecedented accuracy, in a number of local Seyfert galaxies.

  11. Low-frequency radio observations of Seyfert galaxies: A test of the unification scheme

    NASA Astrophysics Data System (ADS)

    Singh, V.; Shastri, P.; Ishwara-Chandra, C. H.; Athreya, R.

    2013-06-01

    Aims: We present low-frequency radio imaging and spectral properties of a well-defined sample of Seyfert galaxies using GMRT 240/610 MHz dual frequency observations. Radio spectra of Seyfert galaxies over 240 MHz to 5.0 GHz are investigated using 240 MHz, 610 MHz flux densities derived from GMRT, and 1.4 GHz and 5.0 GHz flux densities mainly from published VLA data. We test the predictions of Seyfert unification scheme by comparing the radio properties of Seyfert type 1s and type 2s. Methods: We chose a sample such that the two Seyferts subtypes have matched distributions in parameters that are independent of the orientation of AGN, obscuring torus, and the host galaxy. Our sample selection criteria allowed us to assume that the two Seyfert subtypes are intrinsically similar within the framework of the unification scheme. Results: The new observations at 240/610 MHz, together with archival observations at 1.4 GHz, 5.0 GHz show that types 1s and 2s have statistically similar radio luminosity distributions at 240 MHz, 610 MHz, 1.4 GHz, and 5.0 GHz. The spectral indices at selected frequency intervals (α240 MHz610 MHz, α610 MHz1.4 GHz, and α1.4 GHz5.0 GHz), as well as index measured over 240 MHz to 5.0 GHz (αint) for the two Seyfert subtypes, have similar distributions with median spectral index (α) ~ -0.7 (Sν ∝ να), consistent with the synchrotron emission from optically thin plasma. In our snapshot 240/610 MHz GMRT observations, most of the Seyfert galaxies primarily show an unresolved central radio component, except for a few sources in which faint kpc-scale extended emission is apparent at 610 MHz. Our results on the statistical comparison of the multifrequency radio properties of our sample Seyfert galaxies agree with the predictions of the Seyfert unification scheme. Figures 2, 4 and Appendix A are available in electronic form at http://www.aanda.org

  12. Was 49: Mirror for a hidden Seyfert 1 galaxy

    NASA Technical Reports Server (NTRS)

    Halpern, Jules; Moran, E.; Kay, L.; Antonucci, R.

    1993-01-01

    Was 49 is an interacting pair of Seyfert galaxies at z = 0.063, one of which contains a hidden Seyfert 1 nucleus as evidenced by the highly polarized broad wings on its Balmer lines. The disk of the main galaxy, Was 49a, appears to be globally photoionized by a powerful continuum source, undoubtedly the hidden Seyfert 1 companion, Was 49b. The intrinsic luminosity of Was 49b is at least 100 times larger than the observed (scattered) luminosity. A single SWP spectrum of the pair, which can be spatially resolved in the large aperture was obtained. A narrow Ly-alpha line was detected from Was 49b, the hidden Seyfert 1, at a flux level consistent with that of an unreddened Seyfert 2 galaxy. The lack of detection of a continuum is consistent with a power-law of v(sup -1) or steeper extrapolated from the optical, again consistent with the spectrum of other Seyfert 2 and hidden Seyfert 1 galaxies.

  13. 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.

  14. QSO clustering - II. The correlation function of IRAS seyfert galaxies.

    NASA Astrophysics Data System (ADS)

    Georgantopoulos, I.; Shanks, T.

    1994-12-01

    We investigate the clustering properties of 192 Seyfert galaxies from the IRAS all-sky survey. Using the spatial correlation function, we detect evidence of Seyfert clustering at the 2σ confidence level at < 10 h^-1^ Mpc separations, and at the 3{SIGMA} level at < 20 h^-1^ Mpc separations. Comparison of the QSO correlation function amplitude at high redshifts, z = 1.4, with that of Seyferts below 10 h^-1^ comoving Mpc leads us to reject the stable model of AGN clustering evolution at the 4σ level, whereas a comoving model where QSOs randomly sample the galaxy distribution is more consistent. The main uncertainty here now lies in the statistical error on the amplitude of the clustering in the faint QSO surveys at z = 1.4. The Seyfert-QDOT cross-correlation function is measured to be approximately a factor of 2 higher than the QDOT galaxy autocorrelation function, suggesting an enhanced environment for Seyferts with respect to IRAS galaxies, but it is not clear whether this is also the case with respect to optical galaxies. We conclude that the comoving model is probably favoured overall, at least on the r < 10 h^-1^ Mpc scales investigated here, but it is not yet possible to rule out intermediate models: for example, an enhanced-environment, stable model with ξ(r)=(r/3)^-1.8^ at z = 1.4, which is statistically consistent with the faint QSO data.

  15. Narrow Line Seyfert 1 Galaxies and the Evolution of Galaxies and Active Galaxies

    NASA Technical Reports Server (NTRS)

    Mathur, Smita

    2000-01-01

    Narrow Line Seyfert 1 galaxies (NLS1s) are intriguing due to their continuum as well as emission line properties. The observed peculiar properties of the NLS1s are believed to be due to accretion rate close to Eddington limit. As a consequence, for a given luminosity, NLS1s have smaller black hole (BH) masses compared to normal Seyfert galaxies. Here we argue that NLS1s might be Seyfert galaxies in their early stage of evolution and as such may be low redshift, low luminosity analogues of high redshift quasars. We propose that NLS1s may reside in rejuvenated, gas rich galaxies. The also argue in favor of collisional ionization for production of FeII in active galactic nuclei (AGN).

  16. Radio emission and the forbidden line region of Seyfert galaxies

    SciTech Connect

    Ulvestad, J.S.

    1981-01-01

    The results of an extensive program of mapping Seyfert galaxies using the Very Large Array radio telescope are presented. Unlike the majority of radio galaxies, the radio emission in most Seyferts is confined to the inner few kiloparsecs (or less) of the galaxy. This scale is similar to the size of the region in which optical forbidden line emission occurs. Six double (or triple) radio sources have been mapped now in Seyfert galaxies. Approximately ten more galaxies shown more diffuse emission or are resolved only slightly. In almost all galaxies, the central radio peak, when present, coincides with the optical continuum peak. In every double or triple radio source, the outer radio lobes straddle that optical peak. The major axes of the double and triple radio sources may be correlated with the directions of greatest elongation of the optical line-emitting cloud complexes. However, the radio source axes do not appear to be related to the major or minor axes of the outer optical continuum isophotes of the Seyfert galaxies. Synchrotron emission is the dominant source of radio photons in all the galaxies observed. Thermal processes contribute, on the average, no more than about 6% of the total radio emission at 4.885 GHz. Using standard assumptions, radio luminosities, magnetic fields, and total energy contents have been calculated for the observed galaxies. The triple radio source in NGC 5548 has been studied in detail. The properties of NGC 5548 have been used to investigate some theoretical aspects of the double and triple sources and their relationship to the forbidden line region (FLR).

  17. Visible and Near-Infrared Spectroscopy of Seyfert 1 and Narrow-Line Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Rodríguez-Ardila, Alberto; Pastoriza, Miriani G.; Donzelli, Carlos J.

    2000-01-01

    This paper studies the continuum and emission-line properties of a sample composed of 16 normal Seyfert 1 and seven narrow-line Seyfert 1 (NLS1) galaxies using optical and near-IR CCD spectroscopy. The continuum emission of the galaxies can be described in terms of a combination of stellar population, a nonstellar continuum of power-law form, and Fe II emission. A significative difference in the optical spectral index between NLS1's and normal Seyfert 1's is observed; the latter is steeper. Most NLS1's show Fe II/Hβ ratios larger than those observed in the other Seyfert 1's. In the IRAS band, both groups of galaxies have very similar properties. We have searched for the presence of optically thin gas in the broad-line region (BLR) of the galaxies by comparing the broad O I λ8446 and Hα emission-line profiles. Our analysis show that in the NLS1's, both profiles are similar in shape and width. This result contradicts the hypothesis of thin gas emission in the high-velocity part of the BLR to explain the ``narrowness'' of broad optical permitted lines in these objects. Evidence of narrow O I λ8446 emission is found in six galaxies of our sample, implying that this line is not restricted to a pure BLR phenomenon. In the narrow-line region, we find similar luminosities in the permitted and high-ionization lines of NLS1's and normal Seyfert 1's. However, low-ionization lines such as [O I] λ6300, [O II] λ3727, and [S II] λλ6717, 6731 are intrinsically less luminous in NLS1's. Physical properties derived from density- and temperature-sensitive line ratios suggest that the [O II] and [S II] emitting zones are overlapping in normal Seyfert 1's and separated in NLS1's. Based on observations made at CASLEO. Complejo Astronómico El Leoncito (CASLEO) is operated under agreement between the Consejo Nacional de Investigaciones Científicas y técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juán.

  18. 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.

  19. Galaxy gas as obscurer - II. Separating the galaxy-scale and nuclear obscurers of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Buchner, Johannes; Bauer, Franz E.

    2017-03-01

    The 'torus' obscurer of active galactic nuclei (AGN) is poorly understood in terms of its density, sub-structure and physical mechanisms. Large X-ray surveys provide model boundary constraints, for both Compton-thin and Compton-thick levels of obscuration, as obscured fractions are mean covering factors fcov. However, a major remaining uncertainty is host-galaxy obscuration. In Paper I, we discovered a relation of {NH} ∝ M_{star }^{1/3} for the obscuration of galaxy-scale gas. Here, we apply this observational relation to the AGN population, and find that galaxy-scale gas is responsible for a luminosity-independent fraction of Compton-thin AGN, but does not produce Compton-thick columns. With the host-galaxy obscuration understood, we present a model of the remaining nuclear obscurer, which is consistent with a range of observations. Our radiation-lifted torus model consists of a Compton-thick component (fcov ∼ 35 per cent) and a Compton-thin component (fcov ∼ 40 per cent), which depends on both black hole mass and luminosity. This provides a useful summary of observational constraints for torus modellers who attempt to reproduce this behaviour. It can also be employed as a sub-grid recipe in cosmological simulations that do not resolve the torus. We also investigate host-galaxy X-ray obscuration inside cosmological, hydrodynamic simulations (Evolution and Assembly of Galaxies and their Environment; Illustris). The obscuration from ray-traced galaxy gas can agree with observations, but is highly sensitive to the chosen feedback assumptions.

  20. 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.

  1. 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.

  2. Polarimetric view of the changing type Seyfert galaxy ESO 362-G018.

    NASA Astrophysics Data System (ADS)

    Agís-González, B.; Bagnulo, S.; Hutsemékers, D.; Montesinos, B.; Miniutti, G.; Sanfrutos, M.

    2017-03-01

    ESO362-G018 is an active galactic nucleus (AGN) which is classified as a Seyfert 1.5 galaxy e.g. by Bennert et al. (2006), (black data set on figure 1). However, Parisi et. al (2009) found an optical spectrum of this source which was taken during the 6dF Galaxy Survey, but it does not show the broad Balmer lines required to classify it as Seyfert 1 galaxy (red data set on figure 1). On the other hand, the results obtained by Agis-Gonzalez et al. (2014❩ in a X-ray analysis of this same source reveal that the inclination of ESO362- G018 i = 53° ± 5° is consistent with the picture of an AGN looked through the upper layers of a clumpy, dusty torus. Thus, according to the Unification Models of AGN and the clumpy nature of the torus, our interpretation of the different spectra is the following one. On 30th of January of 2003 (when the spectrum belonging to the 6dF survey was obtained), our line of sight intercepted a (or several aligned) torus clump(s) with much greater column density than its environment. Accordingly, the nucleus and the broad line region (❨BLR)❩ would be obscured. This allowed only the narrow emission lines to emerge from the narrow line region (NRL). Otherwise, on 18th of September of 2004 (when the spectrum by Bennert et al. 2006 was obtained) there is no clump to intercept and the BLR is not obscured so that the broad Balmer emission lines could be detected.

  3. Heavily Obscured Star-Forming Regions in the LVL Galaxies

    NASA Astrophysics Data System (ADS)

    Dale, Daniel A.; Aller, K.; Staudaher, S.

    2009-01-01

    We use data from the Spitzer Local Volume Legacy to study the infrared and optical properties of star forming regions in galaxies on 300pc scales. Our main goal is to determine the fraction of heavily-obscured star-forming regions. Here we study 908 regions within 55 galaxies. The median attenuation in Hα is 0.69 mag, and only a small fraction is highly obscured (Aα> 2). There is very little variation in the median attenuation over scales of 200pc to 1000pc.

  4. NGC 4388 - A Seyfert 2 galaxy in the Virgo cluster

    NASA Astrophysics Data System (ADS)

    Phillips, M. M.; Malin, D. F.

    1982-06-01

    Direct photographic data and preliminary spectroscopy of the spiral galaxy NGC 4388 are presented. The galaxy appears to be a barred spiral of morphological class SB(s)b pec and is almost certainly a member of the Virgo cluster. The nucleus was studied with a photon-counting image intensifier/reticon scanner and was found to emit a high-excitation, narrow emission-line spectrum of relatively low luminosity. Image-tube spectrograms and spectroscopy using an image photon-counting system revealed optical, X-ray, and radio nuclear properties consistent with a classical Seyfert 2 galaxy. The radial velocity of the peaks of the asymmetric nuclear emission lines is 55 km/s less than the H I 21 cm systemic velocity.

  5. 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.

  6. 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.

  7. The circumnuclear environment of the Seyfert 1 galaxy NGC 3516

    SciTech Connect

    Pogge, R.W.; McDonald Observatory, Austin, TX )

    1989-07-01

    Results of an emission-line imaging and spectrophotometric study of the ionized gas in the circumnuclear regions of the Seyfert 1 galaxy NGC 3516 are reported. The morphology and ionization of the gas are consistent with excitation by the power law continuum from the active nucleus. The optical emission-line gas is well aligned with the extended 6 cm radio-continuum emission. The ionization, structure, and published kinematical data are strongly suggestive of an outflow origin for the circumnuclear gas, although important details are missing to firmly establish outflow as the origin of all of the ionized gas. 31 refs.

  8. 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.

  9. Testing different AGN tracers on a local sample of Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Pozzi, F.

    2016-08-01

    I will present our new study on a local sample of Seyfert galaxies selected at 12 micron. This sample, given its plenty of information, both photometric and spectroscopic, is a perfect sample to compare, from a statistical point of view, different AGN selection criteria, and AGN derived intrinsic properties. In detail, I will compare AGN activity derived from SED-fitting technique, X-ray luminosity and AGN activity traced by high excitation IR lines, like [NeV] and [OIV]. Moreover, for one particular obscured X-ray Compton-thick source, thanks also to the availability of ALMA data, I will derive a self-consistent overview of the physics behind the emission in different bands,by taking advantage of the photoionization code CLOUDY.

  10. X-ray variability of a polar-scattered Seyfert 1 galaxy Fairall 51

    NASA Astrophysics Data System (ADS)

    Svoboda, J.

    2015-09-01

    Polar-scattered Seyfert 1 galaxies are characterised by an unusually large optical polarisation for the type-1 objects. Therefore, they are believed to represent a bridge between unobscured Type-1 and obscured Type-2 objects. Their X-ray spectra show complex and variable X-ray absorption. I will present our recent results on the Suzaku X-ray monitoring of Fairall 51, whose intrinsic spectrum is affected by at least three absorbers with different ionisations. We found that the least ionised absorber is variable on a week-long scale, from which we constrained the location in the Broad Line Region (BLR). Assuming an intermediate inclination of the source, this implies that the BLR clouds can reach relatively high altitudes above the equatorial plane.

  11. 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.

  12. Infrared spectrophotometry of three Seyfert galaxies and 3C 273

    NASA Technical Reports Server (NTRS)

    Cutri, R. M.; Puetter, R. C.; Rudy, R. J.; Willner, S. P.; Aitken, D. K.; Jones, B.; Merrill, K. M.; Roche, P. F.; Russell, R. W.; Soifer, B. T.

    1981-01-01

    Spectrophotometry in the range 2.1-4.0 microns is presented for the Seyfert galaxies NGC 1068, NGC 4151 and Mrk 231 and the quasar 3C 273, together with broadband and narrowband observations of the Seyfert galaxies in the range 8-13 microns. The spectra of NGC 1068 and NGC 4151 are found to contain a significant component due to starlight, especially at shorter wavelengths. The nonstellar component in NGC 1068 is observed to fall off rapidly at wavelengths shorter than 4 microns, consistent with the interpretation of the excess beyond 5 microns as thermal reradiation by dust. Observations confirm the variability of NGC 4151, and indicate the presence of two components of the flux other than starlight: a nonthermal variable component predominant at shorter wavelengths and a constant, probably thermal component at wavelengths greater than 3 microns. Mrk 231 and 3C 273 exhibit no discernable stellar component and were not observed to vary by more than 10%. Evidence is obtained for a broad minimum in the 8 to 13 micron spectrum of Mrk 231, as well as possible structure between rest wavelengths of 2.8 and 2.9 microns, and the spectrum is not a power law. The spectrum of 3C 273 is consistent with a power law from 1.2 to 10 microns, with small but significant deviations.

  13. IRAS 09149-6206, a new Seyfert I galaxy

    NASA Astrophysics Data System (ADS)

    Perez, E.; Manchado, A.; Garcia-Lario, P.; Pottasch, S. R.

    1989-05-01

    The serendipitous discovery of a new type I Seyfert galaxy, IRAS 09149-6206, found during a search for planetary nebulae using the IRAS Point Source Catalog is reported. The optical spectrum of this galaxy shows very strong broad Balmer and Fe II emission, indicating the existence of large optical depths, while the emission spectrum from the narrow line region is relatively weak, with only the high excitation lines present. The object presents extended forbidden O III emission, and from the rotation curve, a mass of 8 x 10th the 9th solar masses is calculated within a radius of 3 kpc. It is suggested that the activity could have been triggered by interaction with a close faint companion.

  14. Time-dependent effects in the radially streaming particle model. [quasars and Seyfert galaxy emission

    NASA Technical Reports Server (NTRS)

    Hubbard, R.

    1975-01-01

    The radially streaming particle model for broad quasar and Seyfert galaxy emission features is modified to include sources of time dependence. The results seem to correlate with reported observations of multiple components, variability, and transient features in the wings of Seyfert and quasi-stellar emission lines.

  15. 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.

  16. 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.

  17. 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.

  18. Relativistic Fe Kα Line In Bright Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    Relativistic iron lines are expected to be an ubiquitous feature in bright AGN. However, a significant fraction of object misses a relativistic line component. We investigated the physical reasons of its absence. To this aim we studied a sample of Seyfert 1 galaxies where controversial results on the presence of a relativistic line have been previously reported. I will show that high statistics is key to reveal the line: the relativistic Fe Kalpha line is detected at >95% confidence level in observations where the counts in the 5-7 keV energy band are >4 x 10^4. We also st udied the correlation between the relativistic line and the high energy reflection continuum, and explored whether evidences of light bending exist in the data.

  19. Reverberation Mapping of the Seyfert 1 Galaxy NGC 7469

    NASA Astrophysics Data System (ADS)

    Peterson, B. M.; Grier, C. J.; Horne, Keith; Pogge, R. W.; Bentz, M. C.; De Rosa, G.; Denney, K. D.; Martini, Paul; Sergeev, S. G.; Kaspi, S.; Minezaki, T.; Zu, Y.; Kochanek, C. S.; Siverd, R. J.; Shappee, B.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C.; Bord, D. J.; Borman, G. A.; Che, X.; Chen, C.-T.; Cohen, S. A.; Dietrich, M.; Doroshenko, V. T.; Drake, T.; Efimov, Yu. S.; Free, N.; Ginsburg, I.; Henderson, C. B.; King, A. L.; Koshida, S.; Mogren, K.; Molina, M.; Mosquera, A. M.; Motohara, K.; Nazarov, S. V.; Okhmat, D. N.; Pejcha, O.; Rafter, S.; Shields, J. C.; Skowron, D. M.; Skowron, J.; Valluri, M.; van Saders, J. L.; Yoshii, Y.

    2014-11-01

    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 BH ≈ 1 × 107 M ⊙, 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. 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.

  1. Kiloparsec-scale radio emission in Seyfert and LINER galaxies

    NASA Astrophysics Data System (ADS)

    Singh, Veeresh; Ishwara-Chandra, C. H.; Wadadekar, Yogesh; Beelen, Alexandre; Kharb, Preeti

    2015-01-01

    Seyfert and LINER galaxies are known to exhibit compact radio emission on ˜10-100 pc scales, but larger Kiloparsec-Scale Radio structures (KSRs) often remain undetected in sub-arcsec high-resolution observations. We investigate the prevalence and nature of KSRs in Seyfert and LINER galaxies using the 1.4 GHz VLA FIRST and NVSS observations. Our sample consists of 2651 sources detected in FIRST and of these 1737 sources also have NVSS counterparts. Considering the ratio of total to peak flux density (θ = (Sint/Speak)1/2) as a parameter to infer the presence of extended radio emission we show that ≥30 per cent of FIRST-detected sources possess extended radio structures on scales larger than 1.0 kpc. The use of low-resolution NVSS observations help us to recover faint extended KSRs that are resolved out in FIRST observations and results in ≥42.5 per cent KSR sources in FIRST-NVSS sub-sample. This fraction is only a lower limit owing to the combination of projection, resolution and sensitivity effects. Our study demonstrates that KSRs may be more common than previously thought and are found across all redshifts, luminosities and radio loudness. The extranuclear radio luminosity of KSR sources is found to be positively correlated with the core radio luminosity as well as the [O III] λ5007 Å line luminosity and this can be interpreted as KSRs being powered by AGN rather than star formation. The distributions of the FIR-to-radio ratios and mid-IR colours of KSR sources are also consistent with their AGN origin. However, contribution from star formation cannot be ruled out particularly in sources with low radio luminosities.

  2. IRAS 23532+2513: a compact group including a Seyfert 1 and a starburst galaxy.

    NASA Astrophysics Data System (ADS)

    Zou, Z.-L.; Xia, X.-Y.; Deng, Z.-G.; Wu, H.

    1995-12-01

    The very luminous infrared source IRAS 23532 coincides with a compact group of galaxies including MCG 04-01-002, MCG 04-01-003 and MCG 04-01-004. Spectroscopic observations show that the bright-nucleus galaxy MCG 04-01-002 is a Seyfert 1 and the disturbed spiral galaxy MCG 04-01-003 is a starburst galaxy. CCD images in V band reveal that clear tidal interaction exists between those two objects. This is another example of tidal interaction triggering starburst and Seyfert activity.

  3. 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.

  4. Reverberation Mapping Results for Five Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Denney, K. D.; Bentz, M. C.; Martini, Paul; Sergeev, S. G.; Kaspi, S.; Minezaki, T.; Zu, Y.; Kochanek, C. S.; Siverd, R.; Shappee, B.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C.; Bord, D. J.; Borman, G. A.; Che, X.; Chen, C.; Cohen, S. A.; Dietrich, M.; Doroshenko, V. T.; Drake, T.; Efimov, Yu. S.; Free, N.; Ginsburg, I.; Henderson, C. B.; King, A. L.; Koshida, S.; Mogren, K.; Molina, M.; Mosquera, A. M.; Nazarov, S. V.; Okhmat, D. N.; Pejcha, O.; Rafter, S.; Shields, J. C.; Skowron, J.; Szczygiel, D. M.; Valluri, M.; van Saders, J. L.

    2012-08-01

    We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140 day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501, 3C 120, Mrk 6, and PG 2130+099, from which we have measured the time lag between variations in the 5100 Å continuum and the Hβ broad emission line. We then used these measurements to calculate the mass of the supermassive black hole at the center of each of these galaxies. Our new measurements substantially improve previous measurements of M BH and the size of the broad line-emitting region for four sources and add a measurement for one new object. Our new measurements are consistent with photoionization physics regulating the location of the broad line region in active galactic nuclei.

  5. REVERBERATION MAPPING RESULTS FOR FIVE SEYFERT 1 GALAXIES

    SciTech Connect

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

    2012-08-10

    We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140 day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501, 3C 120, Mrk 6, and PG 2130+099, from which we have measured the time lag between variations in the 5100 A continuum and the H{beta} broad emission line. We then used these measurements to calculate the mass of the supermassive black hole at the center of each of these galaxies. Our new measurements substantially improve previous measurements of M{sub BH} and the size of the broad line-emitting region for four sources and add a measurement for one new object. Our new measurements are consistent with photoionization physics regulating the location of the broad line region in active galactic nuclei.

  6. A Submillimeter Continuum Survey of Local Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Jong Chul; Hwang, Ho Seong; Lee, Gwang-Ho

    2016-12-01

    We conduct a 350 μm dust continuum emission survey of 17 dust-obscured galaxies (DOGs) at z = 0.05-0.08 with the Caltech Submillimeter Observatory (CSO). We detect 14 DOGs with S 350 μm = 114-650 mJy and signal-to-noise > 3. By including two additional DOGs with submillimeter data in the literature, we are able to study dust content for a sample of 16 local DOGs, which consist of 12 bump and four power-law types. We determine their physical parameters with a two-component modified blackbody function model. The derived dust temperatures are in the range 57-122 K and 22-35 K for the warm and cold dust components, respectively. The total dust mass and the mass fraction of the warm dust component are 3-34 × 107 M ⊙ and 0.03%-2.52%, respectively. We compare these results with those of other submillimeter-detected infrared luminous galaxies. The bump DOGs, the majority of the DOG sample, show similar distributions of dust temperatures and total dust mass to the comparison sample. The power-law DOGs show a hint of smaller dust masses than other samples, but need to be tested with a larger sample. These findings support that the reason DOGs show heavy dust obscuration is not an overall amount of dust content, but probably the spatial distribution of dust therein.

  7. DUST OBSCURATION IN LYMAN BREAK GALAXIES AT z {approx} 4

    SciTech Connect

    Ho, I-Ting; Wang, Wei-Hao; Morrison, Glenn E.; Miller, Neal A. E-mail: itho@asiaa.sinica.edu.t

    2010-10-20

    Measuring star formation rates (SFRs) in high-z galaxies with their rest-frame ultraviolet (UV) continuum can be uncertain because of dust obscuration. Prior studies had used the submillimeter emission at 850 {mu}m to determine the intrinsic SFRs of rest-frame UV-selected galaxies, but the results suffered from the low sensitivity and poor resolution ({approx}15''). Here, we use ultradeep Very Large Array 1.4 GHz images with {approx}1''-2'' resolutions to measure the intrinsic SFRs. We perform stacking analyses in the radio images centered on {approx}3500 Lyman break galaxies (LBGs) at z {approx} 4 in the Great Observatories Origins Deep Survey-North and South fields selected with Hubble Space Telescope/Advanced Camera for Surveys data. The stacked radio flux is very low, 0.08 {+-} 0.15 {mu}Jy, implying a mean SFR of 6 {+-} 11 M{sub sun} yr{sup -1}. This is comparable to the uncorrected mean UV SFRs of {approx}5 M{sub sun} yr{sup -1}, implying that the z {approx} 4 LBGs have little dust extinction. The low SFR and dust extinction support the previous results that z {approx} 4 LBGs are in general not submillimeter galaxies. We further show that there is no statistically significant excess of dust-hidden star-forming components within {approx}22 kpc from the LBGs.

  8. 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

  9. Dust-obscured galaxies in the local universe

    SciTech Connect

    Hwang, Ho Seong; Geller, Margaret J. E-mail: mgeller@cfa.harvard.edu

    2013-06-01

    We use Wide-field Infrared Survey Explorer (WISE), AKARI, and Galaxy Evolution Explorer (GALEX) data to select local analogs of high-redshift (z ∼ 2) dust obscured galaxies (DOGs). We identify 47 local DOGs with S {sub 12μm}/S {sub 0.22μm} ≥ 892 and S {sub 12μm} > 20 mJy at 0.05 < z < 0.08 in the Sloan Digital Sky Survey data release 7. The infrared (IR) luminosities of these DOGs are in the range 3.4 × 10{sup 10} (L {sub ☉}) ≲ L {sub IR} ≲ 7.0 × 10{sup 11} (L {sub ☉}) with a median L {sub IR} of 2.1 × 10{sup 11} (L {sub ☉}). We compare the physical properties of local DOGs with a control sample of galaxies that have lower S {sub 12μm}/S {sub 0.22μm} but have similar redshift, IR luminosity, and stellar mass distributions. Both WISE 12 μm and GALEX near-ultraviolet (NUV) flux densities of DOGs differ from the control sample of galaxies, but the difference is much larger in the NUV. Among the 47 DOGs, 36% ± 7% have small axis ratios in the optical (i.e., b/a < 0.6), larger than the fraction among the control sample (17% ± 3%). There is no obvious sign of interaction for many local DOGs. No local DOGs have companions with comparable optical magnitudes closer than ∼50 kpc. The large- and small-scale environments of DOGs are similar to the control sample. Many physical properties of local DOGs are similar to those of high-z DOGs, even though the IR luminosities of local objects are an order of magnitude lower than for the high-z objects: the presence of two classes (active galactic nuclei- and star formation-dominated) of DOGs, abnormal faintness in the UV rather than extreme brightness in the mid-IR, and diverse optical morphology. These results suggest a common underlying physical origin of local and high-z DOGs. Both seem to represent the high-end tail of the dust obscuration distribution resulting from various physical mechanisms rather than a unique phase of galaxy evolution.

  10. DUST-OBSCURED STAR FORMATION IN INTERMEDIATE REDSHIFT GALAXY CLUSTERS

    SciTech Connect

    Finn, Rose A.; Desai, Vandana; Rudnick, Gregory; Poggianti, Bianca; Bell, Eric F.; Hinz, Joannah; Zaritsky, Dennis; Jablonka, Pascale; Milvang-Jensen, Bo; Moustakas, John; Rines, Kenneth E-mail: jmoustakas@ucsd.ed

    2010-09-01

    We present Spitzer MIPS 24 {mu}m observations of sixteen 0.4 < z < 0.8 galaxy clusters drawn from the ESO Distant Cluster Survey. This is the first large 24 {mu}m survey of clusters at intermediate redshift. The depth of our imaging corresponds to a total IR luminosity of 8 x 10{sup 10} L{sub sun}, just below the luminosity of luminous infrared galaxies (LIRGs), and 6{sup +1}{sub -1}% of M{sub V} < -19 cluster members show 24 {mu}m emission at or above this level. We compare with a large sample of coeval field galaxies and find that while the fraction of cluster LIRGs lies significantly below that of the field, the IR luminosities of the field and cluster galaxies are consistent. However, the stellar masses of the EDisCS LIRGs are systematically higher than those of the field LIRGs. A comparison with optical data reveals that {approx}80% of cluster LIRGs are blue and the remaining 20% lie on the red sequence. Of LIRGs with optical spectra, 88{sup +4} {sub -5}% show [O II] emission with EW([O II]) > 5 A, and {approx}75% exhibit optical signatures of dusty starbursts. On average, the fraction of cluster LIRGs increases with projected clustercentric radius but remains systematically lower than the field fraction over the area probed (<1.5x R {sub 200}). The amount of obscured star formation declines significantly over the 2.4 Gyr interval spanned by the EDisCS sample, and the rate of decline is the same for the cluster and field populations. Our results are consistent with an exponentially declining LIRG fraction, with the decline in the field delayed by {approx}1 Gyr relative to the clusters.

  11. Broad iron K emission line and spectral variability of the Seyfert 2 galaxy IRAS 18325-5926

    NASA Technical Reports Server (NTRS)

    Iwasawa, K.; Fabian, A. C.; Mushotsky, R. F.; Brandt, W. N.; Awaki, H.; Kunieda, H.

    1996-01-01

    A very broad iron K alpha emission line is observed in the Advanced Satellite for Cosmology and Astrophysics (ASCA) spectrum of the Seyfert 2 galaxy IRAS 18325-5926. The line profile is peaked at 6.9 keV and skewed down to 4 keV. The breadth and shift of the line energy can be interpreted by Doppler and relativistic effects in a cold accretion disk about a black hole with a intermediate inclination of between 40 and 50 deg. The steep spectral slope and the fast variability on a timescale of 10(exp 4) s are confirmed for this object. A study of spectral variability reveal that the X-ray flux change mainly occurred above 1 keV and the soft X-ray component below 1 keV appears to be less variable or constant and should lie outside of the nuclear obscuration.

  12. Multimolecule ALMA observations toward the Seyfert 1 galaxy NGC 1097

    NASA Astrophysics Data System (ADS)

    Martín, S.; Kohno, K.; Izumi, T.; Krips, M.; Meier, D. S.; Aladro, R.; Matsushita, S.; Takano, S.; Turner, J. L.; Espada, D.; Nakajima, T.; Terashima, Y.; Fathi, K.; Hsieh, P.-Y.; Imanishi, M.; Lundgren, A.; Nakai, N.; Schinnerer, E.; Sheth, K.; Wiklind, T.

    2015-01-01

    Context. The nearby Sy 1 galaxy NGC 1097 represents an ideal laboratory for exploring the molecular chemistry in the surroundings of an active galactic nucleus (AGN). Aims: Exploring the distribution of different molecular species allows us to understand the physical processes affecting the interstellar medium both in the AGN vicinity and in the outer star forming molecular ring. Methods: We carried out 3 mm ALMA observations that include seven different molecular species, namely HCN, HCO+, CCH, CS, HNCO, SiO, HC3N, and SO, as well as the 13C isotopologues of the first two. Spectra were extracted from selected positions and all species were imaged over the central 2 kpc (~30'') of the galaxy at a resolution of ~2.2'' × 1.5'' (150 pc × 100 pc). Results: HCO+ and CS appear to be slightly enhanced in the star forming ring. CCH shows the largest variations across NGC 1097 and is suggested to be a good tracer of both obscured and early stage star formation. HNCO, SiO, and HC3N are significantly enhanced in the inner circumnuclear disk surrounding the AGN. Conclusions: Differences in the molecular abundances are observed between the star forming ring and the inner circumnuclear disk. We conclude that the HCN/HCO+ and HCN/CS differences observed between AGN-dominated and starburst (SB) galaxies are not due to a HCN enhancement due to X-rays, but rather this enhancement is produced by shocked material at distances of 200 pc from the AGN. Additionally, we claim that lower HCN/CS is a combination of a small underabundance of CS in AGNs, together with excitation effects, where a high density gas component (~106 cm-3) may be more prominent in SB galaxies. However, the most promising are the differences found among the dense gas tracers that, at our modest spatial resolution, seem to outline the physical structure of the molecular disk around the AGN. In this picture, HNCO probes the well-shielded gas in the disk, surrounding the dense material moderately exposed to the X

  13. Far-ultraviolet and optical spectrophotometry of X-ray selected Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Clarke, J. T.; Bowyer, S.; Grewing, M.

    1986-01-01

    Five X-ray selected Seyfert galaxies were examined via near-simultaneous far-ultraviolet and optical spectrophotometry in an effort to test models for excitation of emission lines by X-ray and ultraviolet continuum photoionization. The observed Ly-alpha/H-beta ratio in the present sample averages 22, with an increase found toward the high-velocity wings of the H lines in the spectrum of at least one of the Seyfert I nuclei. It is suggested that Seyfert galaxies with the most high-velocity gas exhibit the highest Ly-alpha/H-beta ratios at all velocities in the line profiles, and that sometimes this ratio may be highest for the highest velocity material in the broad-line clouds. Since broad-lined objects are least affected by Ly-alpha trapping effects, they have Ly-alpha/H-beta ratios much closer to those predicted by early photoionization calculations.

  14. Data-driven dissection of emission-line regions in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Villarroel, Beatriz; Korn, Andreas J.

    2016-11-01

    Aims: Indirectly resolving the line-emitting gas regions in distant active galactic nuclei (AGN) requires both high-resolution photometry and spectroscopy (i.e. through reverberation mapping). Emission in AGN originates on widely different scales; the broad-line region (BLR) has a typical radius less than a few parsec, the narrow-line region (NLR) extends out to hundreds of parsecs. But emission also appears on large scales from heated nebulae in the host galaxies (tenths of kpc). Methods: We propose a novel, data-driven method based on correlations between emission-line fluxes to identify which of the emission lines are produced in the same kind of emission-line regions. We tested the method on Seyfert galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) and Galaxy Zoo project. Results: We demonstrate the usefulness of the method on Seyfert-1s and Seyfert-2 objects, showing similar narrow-line regions (NLRs). Preliminary results from comparing Seyfert-2s in spiral and elliptical galaxy hosts suggest that the presence of particular emission lines in the NLR depends both on host morphology and eventual radio-loudness. Finally, we explore an apparent linear relation between the final correlation coefficient obtained from the method and time lags as measured in reverberation mapping for Zw229-015.

  15. Search for high energy neutrinos from Seyfert galaxies using IceCube

    NASA Astrophysics Data System (ADS)

    Relethford, Ben; IceCube Collaboration

    2017-01-01

    Since its construction began in 2005, The IceCube Neutrino Observatory, a cubic kilometer Cherenkov detector buried deep in the geographic South Pole ice, has searched for a high-energy astrophysical neutrino flux. In 2013, IceCube observed such a flux deviating at least 5.7 σ above atmospheric backgrounds. However, analyses of promising source candidates such as blazars (a type of radio-loud Active Galactic Nucleus, or AGN) and gamma ray bursts have found no evidence of neutrino emission, placing stringent constraints on their possible contribution to the observed extraterrestrial neutrino flux. This analysis considers a numerous yet comparatively low-intensity type of radio-quiet AGN known as Seyfert galaxies as a new candidate source of high energy astrophysical neutrinos. We obtain a catalog of Seyfert galaxies from the 70 month catalog of high-energy x-ray sources as identified by the BAT detector on the Swift satellite. We simultaneously study these Seyfert galaxies via a stacking analysis, which is particularly well-suited to a source class with high abundance but relatively low-intensity. This analysis will probe for the first time whether Seyfert galaxies contribute significantly to the observed, but so far unresolved astrophysical neutrino flux.

  16. 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.

  17. Time dependent emission line profiles in the radially streaming particle model of Seyfert galaxy nuclei and quasi-stellar objects

    NASA Technical Reports Server (NTRS)

    Hubbard, R.

    1974-01-01

    The radially-streaming particle model for broad quasar and Seyfert galaxy emission features is modified to include sources of time dependence. The results are suggestive of reported observations of multiple components, variability, and transient features in the wings of Seyfert and quasi-stellar emission lines.

  18. Hubble Space Telescope Observations of the CFA Seyfert 2 Galaxies: The Fueling of Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Martini, Paul; Pogge, Richard W.

    1999-12-01

    We present an investigation of possible fueling mechanisms operating in the inner kiloparsec of Seyfert galaxies. We analyze visible and near-infrared Hubble Space Telescope images of 24 Seyfert 2 galaxies from the CfA Redshift Survey sample. In particular, we are searching for the morphological signatures of dynamical processes responsible for transporting gas from kiloparsec scales into the nucleus. The circumnuclear regions are very rich in gas and dust, often taking the form of nuclear spiral dust lanes on scales of a few hundred parsecs. While these nuclear spirals are found in 20 of our 24 Seyfert galaxies, we find only five nuclear bars among the entire sample, strongly reinforcing the conclusions of other investigators that nuclear bars are not the primary means of transporting this material into the nucleus. An estimate of the gas density in the nuclear spirals, based on extinction measurements, suggests that the nuclear spiral dust lanes are probably shocks in nuclear gas disks that are not strongly self-gravitating. Since shocks can dissipate energy and angular momentum, these spiral dust lanes may be the channels by which gas from the host galaxy disks is being fed into the central engines.

  19. Optical Properties of Radio-Selected Narrow Line Seyfert 1 Galaxies

    SciTech Connect

    Whalen, J; Laurent-Muehleisen, S A; Moran, E C; Becker, R H

    2006-01-05

    We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 galaxies (NLS1s). These objects are a subset of the First Bright Quasar Survey (FBQS) and were initially detected at 20 cm (flux density limit {approx} 1 mJy) in the VLA FIRST Survey. We run Spearman rank correlation tests on several sets of parameters and conclude that, except for their radio properties, radio-selected NLS1 galaxies do not exhibit significant differences from traditional NLS1 galaxies. Our results are also in agreement with previous studies suggesting that NLS1 galaxies have small black hole masses that are accreting very close to the Eddington rate. We have found 16 new radio-loud NLS1 galaxies, which increases the number of known radio-loud NLS1 galaxies by a factor of {approx} 5.

  20. ESO 103-G35 - A new Seyfert galaxy and possible X-ray source

    NASA Technical Reports Server (NTRS)

    Phillips, M. M.; Feldman, F. R.; Marshall, F. E.; Wamsteker, W.

    1979-01-01

    By means of an objective prism plate, two emission-line galaxies have been identified within the 0.7-sq deg HEAO-A2 error box for the X-ray source H1834-653. Optical spectrophotometric observations are reported for both objects as well as the galaxy NGC 6684, which also lies near the position of H1834-653. These data show that one of the emission-line galaxies, ESO 103-G35, is a Seyfert galaxy with a high-excitation forbidden-line spectrum and weak broad emission wings at H-alpha. Further measurements of this galaxy reveal an infrared excess at wavelengths longer than 2.2 microns. The H-alpha luminosity of ESO 103-G35 is consistent with the X-ray luminosity estimated from the HEAO-A2 data, thus strengthening the likelihood of association of this galaxy with the X-ray emission.

  1. Basic properties of Narrow-Line Seyfert 1 Galaxies with relativistic jets

    NASA Astrophysics Data System (ADS)

    Foschini, L.; Angelakis, E.; Bonnoli, G.; Braito, V.; Caccianiga, A.; Fuhrmann, L.; Gallo, L.; Ghirlanda, G.; Ghisellini, G.; Grupe, D.; Hamilton, T.; Kaufmann, S.; Komossa, S.; Kovalev\\inst{7 2}, Y. Y.; Lahteenmaki, A.; Lister, M. L.; Mannheim, K.; Maraschi, L.; Mathur, S.; Peterson, B. M.; Romano, P.; Severgnini, P.; Tagliaferri, G.; Tammi, J.; Tavecchio, F.; Tibolla, O.; Tornikoski, M.; Vercellone, S.

    We present the preliminary results of a survey performed with Swift to observe a sample of radio-loud Narrow-Line Seyfert 1 Galaxies (RLNLS1s). Optical-to-X-ray data from Swift are complemented with gamma -ray observations from Fermi/LAT and radio measurements available in the literature. The comparison with a sample of bright Fermi blazars indicates that RLNLS1s seem to be the low-power tail of the distribution.

  2. 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.

  3. A systematic observational study of radio properties of H2O megamaser Seyfert-2 galaxies

    NASA Astrophysics Data System (ADS)

    Liu, Z. W.; Zhang, J. S.; Henkel, C.; Liu, J.; Müller, P.; Wang, J. Z.; Guo, Q.; Wang, J.; Li, J.

    2017-04-01

    A systematic study is performed on radio properties of H2O megamaser host Seyfert 2 galaxies, through multiband radio continuum observations (at 11, 6.0, 3.6, 2.0 and 1.3 cm) with the Effelsberg 100-m radio telescope within a total time duration of 4 d. For comparison, a control Seyfert 2 galaxy sample without detected maser emission was also observed. Spectral indices were determined for those sources for which measurements exist at two adjacent bands assuming a power-law dependence Sν ∝ ν-α, where S is the flux density and ν is the frequency. Comparisons of the radio continuum properties between megamaser and non-masing Seyfert 2s show no difference in spectral indices. However, a difference in radio luminosity is statistically significant, i.e. the maser galaxies tend to have higher radio luminosities by a factor of 2-3 than the non-masing ones, commonly reaching values above a critical threshold of 1029 erg s-1 Hz-1. This result confirms an earlier conclusion by Zhang et al., but is based on superior data with respect to the time interval within which the data were obtained, with respect to the observational facility (only one telescope used), and the number of frequency bands.

  4. Radio constraints on heavily obscured star formation within dark gamma-ray burst host galaxies

    SciTech Connect

    Perley, D. A.; Perley, R. A.

    2013-12-01

    Highly dust-obscured starbursting galaxies (submillimeter galaxies and their ilk) represent the most extreme sites of star formation in the distant universe and contribute significantly to overall cosmic star formation beyond z > 1.5. Some stars formed in these environments may also explode as gamma-ray bursts (GRBs) and contribute to the population of 'dark' bursts. Here we present Very Large Array wideband radio-continuum observations of 15 heavily dust-obscured Swift GRBs to search for radio synchrotron emission associated with intense star formation in their host galaxies. Most of these targets (11) are not detected. Of the remaining four objects, one detection is marginal, and for two others we cannot yet rule out the contribution of a long-lived radio afterglow. The final detection is secure, but indicates a star formation rate (SFR) roughly consistent with the dust-corrected UV-inferred value. Most galaxies hosting obscured GRBs are therefore not forming stars at extreme rates, and the amount of optical extinction seen along a GRB afterglow sightline does not clearly correlate with the likelihood that the host has a sufficiently high SFR to be radio-detectable. While some submillimeter galaxies do readily produce GRBs, these GRBs are often not heavily obscured—suggesting that the outer (modestly obscured) parts of these galaxies overproduce GRBs and the inner (heavily obscured) parts underproduce GRBs relative to their respective contributions to star formation, hinting at strong chemical or initial mass function gradients within these systems.

  5. 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.

  6. A Supermassive Black Hole in the Seyfert 1 Galaxy NGC 3783

    NASA Technical Reports Server (NTRS)

    Onken, C. A.; Peterson, B. M.

    2004-01-01

    Updated analysis techniques and recalibrated archival monitoring data for the Seyfert 1 galaxy NGC 3783 indicated the presence of a supermassive black hole in this galaxy. Using UV data from the International Ultraviolet Explorer satellite and ground-based optical spectra, we have measured more precise emission line reverberation in response to continuum variations. The stratification of the broad line region (BLR) suggested by our results, combined with estimates of the line velocity widths, is consistent with a gravitationally-dominated BLR and allows us to derive a mass for the central black hole.

  7. OXAF: Ionizing spectra of Seyfert galaxies for photoionization modeling

    NASA Astrophysics Data System (ADS)

    Thomas, Adam D.; Groves, Brent A.; Sutherland, Ralph S.; Dopita, Michael A.; Jin, Chichuan; Kewley, Lisa J.

    2016-11-01

    OXAF provides a simplified model of Seyfert Active Galactic Nucleus (AGN) continuum emission designed for photoionization modeling. It removes degeneracies in the effects of AGN parameters on model spectral shapes and reproduces the diversity of spectral shapes that arise in physically-based models. OXAF accepts three parameters which directly describe the shape of the output ionizing spectrum: the energy of the peak of the accretion disk emission Epeak, the photon power-law index of the non-thermal X-ray emission Γ, and the proportion of the total flux which is emitted in the non-thermal component pNT. OXAF accounts for opacity effects where the accretion disk is ionized because it inherits the ‘color correction’ of OPTXAGNF, the physical model upon which OXAF is based.

  8. The Mid-Infrared Emission of Seyfert Galaxies: A New Analysis of ISOCAM Data

    NASA Astrophysics Data System (ADS)

    Ramos Almeida, C.; Pérez García, A. M.; Acosta-Pulido, J. A.; Rodríguez Espinosa, J. M.

    2007-11-01

    We present mid-infrared data of a sample of 57 AGNs obtained with the instrument ISOCAM on board the Infrared Space Observatory (ISO) satellite. The images were obtained through the LW2 (6.75 μm) and LW7 (9.62 μm) filters. This is a new analysis of the Clavel et al. galaxy sample, which is divided into 26 type 1 (<=1.5) and 28 type 2 (>1.5) Seyfert galaxies, plus three QSOs. The spatial resolution of the images allows us to separate the nuclear and the extended contributions to the total emission after decomposing the brightness profiles into different morphological components. The most common components are a central point source (identified as the active nucleus) and an exponential disk. In some cases a bulge, a bar, or a ring are needed. The relative contribution of the nucleus to the total emission appears larger in Seyfert 1 than in Seyfert 2 types. This result confirms that both types of Seyfert galaxies are different in the mid-infrared wavelength range and supports the existence of a structure which produces anisotropic emission in this wavelength range. We have also explored correlations between the mid-infrared and the radio and X-ray wavelength ranges. The well-established radio/infrared correlation is maintained in our sample for the global emission of the galaxies. If only the nuclear infrared emission is considered, then a nonlinear correlation is apparent in the luminosity-luminosity scatter diagram. The ratio between the intrinsic hard X-ray and the nuclear mid-infrared emission presents large scatter and slightly larger values for type 2 Seyfert galaxies. These results seem to be consistent with the presence of a clumpy dusty torus surrounding the active nucleus. Based on observations with the Infrared Space Observatory, an ESA project with instruments funded by the ESA member states (especially the PI countries: France, Germany, the Netherlands, and the United Kingdom) and with the participation of ISAS and NASA.

  9. The Keck OSIRIS Nearby AGN Survey: Tracing Inflow within the Central 200 pc of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Hicks, Erin K. S.; Müller-Sánchez, Francisco; Malkan, Matthew A.; Yu, Po-Chieh

    2016-08-01

    In an effort to identify the fundamental processes driving feeding and feedback in AGN we turn to local Seyfert galaxies and rely on a multi-wavelength approach. With the integral field unit OSIRIS and adaptive optics we characterize the nuclear stars and gas down to scales of 5-30 parsecs in a sample of 40 Seyfert galaxies with the Keck OSIRIS Nearby AGN (KONA) survey. The complex gas kinematics in these near-IR data are interpreted using an integrative approach through comparison with data available at a range of wavelengths. We present first results from the survey with a focus on work aimed at constraining the mechanism(s) driving inflow of material within the central 200 pc. Particularly useful in the identification of inflow mechanisms (e.g. nuclear spiral, external accretion) is spatial correlation of the molecular gas distribution and kinematics with dust features revealed in HST imaging (optical and near-IR). Also informative is comparison with X-ray emission to identify locations likely influenced by interactions with outflows. The stellar kinematics in the sample galaxies (traced by CO bandheads at 2.3 microns) indicate a stellar population within the central few 100 parsecs in circular rotation, and in the majority of the galaxies the molecular gas (traced by H2 emission at 2.1218 microns) is found to have a rotating component co-spatial with the stellar disk. A significant fraction of the galaxies also exhibit kinematic signatures of inflow superimposed on this disk rotation, with inflow driven by secular and non-secular processes identified. We explore statistical trends of the nuclear stellar and molecular gas properties, including primary fueling mechanism, with Seyfert type, AGN luminosity, and host environment with the goal of disentangling which properties are fundamental to the nature of the AGN.

  10. Active Galaxy Winds from X-ray, Ultraviolet, and Optical Studies of Nearby Seyfert 1s

    NASA Astrophysics Data System (ADS)

    Winter, Lisa M.

    2012-01-01

    Mass outflows or winds from active galaxies may profoundly affect the evolution of their host galaxies by blowing away gas from star forming regions and recycling metals from near-nuclear supernovae into the galaxy disk. Such fundamental properties as the covering fraction, total energy, variability, and distance of these outflows are still unknown. We present new results in an effort to better understand the properties of active galaxy winds based on X-ray, optical, and UV observations of local Seyfert 1s. We show that the covering fraction, indicated through X-ray and optical spectroscopy, is higher than previous studies suggest. We also show new observations in the UV with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS), showing that the UV variability is at a much lower level than X-ray variability. The COS observations also reveal weak Ly-alpha outflows, which were difficult/impossible to detect in previous generations of UV spectrographs.

  11. 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.

  12. 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.

  13. HEAVILY OBSCURED ACTIVE GALACTIC NUCLEI IN HIGH-REDSHIFT LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Treister, Ezequiel; Sanders, David B.; Urry, C. Megan; Cardamone, Carolin N.; Schawinski, Kevin

    2010-10-20

    We take advantage of the rich multiwavelength data available in the Chandra Deep Field South (CDF-S), including the 4 Ms Chandra observations (the deepest X-ray data to date), in order to search for heavily obscured low-luminosity active galactic nuclei (AGNs) among infrared-luminous galaxies. In particular, we obtained a stacked rest-frame X-ray spectrum for samples of galaxies binned in terms of their IR luminosity or stellar mass. We detect a significant signal at E {approx} 1-8 keV, which we interpret as originating from a combination of emission associated with star formation processes at low energies combined with a heavily obscured AGN at E > 5 keV. We further find that the relative strength of this AGN signal decays with decreasing IR luminosity, indicating a higher AGN fraction for more luminous IR sources. Together, these results strongly suggest the presence of a large number of obscured AGNs in IR-luminous galaxies. Using samples binned in terms of stellar mass in the host galaxy, we find a significant excess at E = 6-7 keV for sources with M > 10{sup 11} M {sub sun}, consistent with a large obscured AGN population in high mass galaxies. In contrast, no strong evidence of AGN activity was found for less-massive galaxies. The integrated intensity at high energies indicates that a significant fraction of the total black hole growth, {approx}22%, occurs in heavily obscured systems that are not individually detected in even the deepest X-ray observations. There are also indications that the number of low-luminosity, heavily obscured AGNs does not evolve significantly with redshift, in contrast to the strong evolution seen in higher luminosity sources.

  14. Intra-night optical variability characteristics of different classes of narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Kshama, S. K.; Paliya, Vaidehi S.; Stalin, C. S.

    2017-04-01

    In a first systematic effort to characterize the intra-night optical variability (INOV) of different classes of narrow-line Seyfert 1 (NLSy1) Galaxies, we have carried out observations on a sample of radio-loud (RL) and radio-quiet (RQ) NLSy1 galaxies. The RL-NLSy1 galaxies are further divided into γ-ray loud (GL) and γ-ray quiet (GQ) NLSy1 galaxies. Our sample consists of four sets, each set consisting of a RQ-NLSy1, a GQ-NLSy1 and a GL-NLSy1 galaxy, closely matched in redshift and optical luminosity. Our observations on both RQ- and GQ-NLSy1 galaxies consist of a total of 19 nights, whereas the data for GL-NLSy1 galaxies (18 nights) were taken from the literature published earlier by us. This enabled us to do a comparison of the duty cycle (DC) of different classes of NLSy1 galaxies. Using power-enhanced F-test, with a variability threshold of 1 per cent, we find DCs of about 55 per cent, 39 per cent and 0 per cent for GL-, GQ- and RQ-NLSy1 galaxies, respectively. The high DC and large amplitude of INOV (24.0 ± 13.7 per cent) shown by GL-NLSy1 galaxies relative to the other two classes might be due to their inner aligned relativistic jets having large bulk Lorentz factors. The null DC of RQ-NLSy1 galaxies could mean the presence of low power and/or largely misaligned jets in them. However, dividing RL-NLSy1 galaxies into low and high optical polarization sources, we find that sources with large polarization show somewhat higher DCs (69 per cent) and amplitudes (29 per cent) compared to those with low polarization. This points to a possible link between INOV and optical polarization.

  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. 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.

  17. A new sample of X-ray selected narrow emission-line galaxies. II. Looking for True Seyfert 2

    NASA Astrophysics Data System (ADS)

    Pons, E.; Watson, M. G.

    2016-10-01

    A sample of X-ray and optically selected narrow emission-line galaxies (769 sources) from the 3XMM catalogue cross-correlated with SDSS (DR9) catalogue has been studied. Narrow-emission line active galactic nuclei (AGN; type-2) have been selected on the basis of their emission line ratios and/or X-ray luminosity. We have looked for X-ray unobscured type-2 AGN. As X-ray spectra were not available for our whole sample, we have checked the reliability of using the X-ray hardness ratio (HR) as a probe of the level of obscuration and we found a very good agreement with full spectral fitting results, with only 2% of the sources with apparently unobscured HR turning out to have an obscured spectrum. Despite the fact that type-2 AGN are supposed to be absorbed based on the Unified Model, about 60% of them show no sign or very low level of X-ray obscuration. After subtraction of contaminants to the sample, that is Narrow-Line Seyfert 1 and Compton-thick AGN, the fraction of unobscured Sy2 drops to 47%. For these sources, we were able to rule out dust reddening and variability for most of them as an explanation of the absence of optical broad emission-lines. The main explanations remaining are the dilution of weak/very broad emission-lines by the host galaxy and the intrinsic absence of the broad-line region (BLR) due to low accretion rates (i.e. True Sy2). However, the number of True Sy2 strongly depends on the method used to verify the intrinsic lack of broad lines. Indeed using the optical continuum luminosity to predict the BLR properties gives a much larger fraction of True Sy2 (about 90% of the unobscured Sy2 sample) than the use of the X-ray 2 keV luminosity (about 20%). Nevertheless the number of AGN we securely detected as True Sy2 is at least three times larger that the previously confirmed number of True Sy2.

  18. 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.

  19. GAS OUTFLOWS IN SEYFERT GALAXIES: EFFECTS OF STAR FORMATION VERSUS AGN FEEDBACK

    SciTech Connect

    Melioli, C.; Pino, E. M. de Gouveia Dal E-mail: dalpino@iag.usp.br

    2015-10-20

    Large-scale, weakly collimated outflows are very common in galaxies with large infrared luminosities. In complex systems in particular, where intense star formation (SF) coexists with an active galactic nucleus (AGN), it is not clear yet from observations whether the SF, the AGN, or both are driving these outflows. Accreting supermassive black holes are expected to influence their host galaxies through kinetic and radiative feedback processes, but in a Seyfert galaxy, where the energy emitted in the nuclear region is comparable to that of the body of the galaxy, it is possible that stellar activity is also playing a key role in these processes. In order to achieve a better understanding of the mechanisms driving the gas evolution especially at the nuclear regions of these galaxies, we have performed high-resolution three-dimensional hydrodynamical simulations with radiative cooling considering the feedback from both SF regions, including supernova (Type I and II) explosions and an AGN jet emerging from the central region of the active spiral galaxy. We computed the gas mass lost by the system, separating the role of each of these injection energy sources on the galaxy evolution, and found that at scales within 1 kpc an outflow can be generally established considering intense nuclear SF only. The jet alone is unable to drive a massive gas outflow, although it can sporadically drag and accelerate clumps of the underlying outflow to very high velocities.

  20. On the emission-line response to continuum variations in the Seyfert galaxy NGC 5548

    NASA Astrophysics Data System (ADS)

    Netzer, Hagai; Maoz, Dan

    1990-12-01

    The two optical monitoring groups which have recently attempted to ascertain the continuum and emission-line variations in the Seyfert galaxy NGC 5548 have reported apparently contradictory results for the delay of H-beta variations with respect to the continuum. The measurements of Clavel et al. (1991) are presently used to demonstrate that the emission-line lag behind continuum variations depends on the continuum variability time-scale in this object, in the sense that continuum variations with larger time-scales yield larger emission-line lags. Monte Carlo simulations are used to show that there is at least one possible model which can reproduce the two differing delays.

  1. Evidence of coronal flaring in narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Gallo, L. C.

    High-energy (E>2 keV) continuum flaring is detected in two narrow-line Seyfert 1 galaxies (I Zw 1 and NAB 0205+024), consistent with occurring in a hot corona distinct from the accretion disc. The flare in I Zw 1 is accompanied by an increase in the amount of gravitationally redshifted reflected emission coming from the accretion disc. This indicates that the high-energy continuum component is compact and located close to the black hole, and could possibly be the base of an aborted jet.

  2. 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.

  3. The nature of the optical variations of Seyfert galaxy 3C 120

    SciTech Connect

    Webb, J.R. Austin State Univ., TX )

    1990-01-01

    Results are presented from 61 years of optical observations of the Seyfert galaxy 3C 120. A previously published model of the 3C 120 light curve, derived from power spectrum analysis, is found to be valid for historical as well as current data. It is concluded that the optical variations of 3C 120 can be separated into a linear component, a sinusoidal component, and rapid, high-amplitude flares. Possible sources of the regular variations observed in 3C 120 are also suggested in the context of accretion models and other theoretical models. 15 refs.

  4. Are Narrow Line Seyfert 1 Galaxies Viewed Pole-on?

    DTIC Science & Technology

    2011-04-01

    0.2’’ respectively. Figure 1 displays the position of each slit over a Barbosa et al. (2009) GMOS IFU image of the [S III] flux (which originates...C. Winge, H. Schmitt: Gemini/ GMOS IFU gas velocity ’tomography’ of the narrow line region of nearby active galaxies, MNRAS, 396 (2009) 2. [2] D...1995) 81. 4 P o S ( N L S 1 ) 0 5 0 Are NLS1s Pole-on? Travis C. Fischer 5 Figure 1: NGC 4051 GMOS IFU image showing integrated [SIII] flux

  5. Evolutionary behaviour of AGN: Investigations on BL Lac objects and Seyfert II galaxies

    NASA Astrophysics Data System (ADS)

    Beckmann, V.

    2000-12-01

    The evolution and nature of AGN is still one of the enigmatic questions in astrophysics. While large and complete Quasar samples are available, special classes of AGN, like BL Lac objects and Seyfert II galaxies, are still rare objects. In this work I present two new AGN samples. The first one is the HRX-BL Lac survey, resulting in a sample of X-ray selected BL Lac objects. This sample results from 223 BL Lac candidates based on a correlation of X-ray sources with radio sources. The identification of this sample is 98% complete. 77 objects have been identified as BL Lac objects and form the HRX-BL Lac complete sample, the largest homogeneous sample of BL Lac objects existing today. For this sample, redshifts are now known for 62 objects (81 %). In total I present 101 BL Lac objects in the enlarged HRX-BL Lac survey, for which redshift information is available for 84 objects. During the HRX-BL Lac survey I found several objects of special interest. 1ES 1517+656 turned out to be the brightest known BL Lac object in the universe. 1ES 0927+500 could be the first BL Lac object with a line detected in the X-ray region. RX J1211+2242 is probably the the counterpart of the up to now unidentified gamma-ray source 3EG J1212+2304. Additionally I present seven candidates for ultra high frequency peaked BL Lac objects. RX J1054+3855 and RX J1153+3517 are rare high redshift X-ray bright QSO or accreting binary systems with huge magnetic fields. For the BL Lac objects I suggest an unified scenario in which giant elliptical galaxies, formed by merging events of spiral galaxies at z > 2, start as powerful, radio dominated BL Lacs. As the jet gets less powerful, the BL Lacs start to get more X-ray dominated, showing less total luminosities (for z < 1). This effect is seen in the different evolutionary behavior detected in high and low frequency cut off BL Lac objects (HBL and LBL, respectively). The model of negative evolution is supported by assumptions about the energetic effects

  6. 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.

  7. Probing the active galactic nucleus unified model torus properties in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Audibert, Anelise; Riffel, Rogério; Sales, Dinalva A.; Pastoriza, Miriani G.; Ruschel-Dutra, Daniel

    2017-01-01

    We studied the physical parameters of a sample comprising of all Spitzer/Infrared Spectrograph public spectra of Seyfert galaxies in the mid-infrared (5.2-38 μm range) under the active galactic nucleus (AGN) unified model. We compare the observed spectra with ˜106 CLUMPY model spectral energy distributions, which consider a torus composed of dusty clouds. We find a slight difference in the distribution of line-of-sight inclination angle, i, requiring larger angles for Seyfert 2 (Sy 2) and a broader distribution for Seyfert 1 (Sy 1). We found small differences in the torus angular width, σ, indicating that Sy 1 may host a slightly narrower torus than Sy 2. The torus thickness, together with the bolometric luminosities derived, suggests a very compact torus up to ˜6 pc from the central AGN. The number of clouds along the equatorial plane, N, as well the index of the radial profile, q, is nearly the same for both types. These results imply that the torus cloud distribution is nearly the same for type 1 and type 2 objects. The torus mass is almost the same for both types of activity, with values in the range of Mtor ˜ 104-107 M⊙. The main difference appears to be related to the clouds' intrinsic properties: type 2 sources present higher optical depths τV. The results presented here reinforce the suggestion that the classification of a galaxy may also depend on the intrinsic properties of the torus clouds rather than simply on their inclination. This is in contradiction with the simple geometric idea of the unification model.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

    Kara, E.; Alston, W. N.; Fabian, A. C.; Cackett, E. M.; Uttley, P.; Reynolds, C. S.; Zoghbi, A.

    2016-10-01

    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 Seyfert galaxies. In this work, we expand the study of X-ray reverberation to all Seyfert galaxies in the XMM-Newton archive above a nominal rms variability and exposure level (a total of 43 sources). Approximately 50 per cent of sources exhibit iron K reverberation, in that the broad iron K emission line responds to rapid variability in the continuum. We also find that on long time-scales, the hard band emission lags behind the soft band emission in 85 per cent of sources. This `low-frequency hard lag' is likely associated with the coronal emission, and so this result suggests that most sources with X-ray variability show intrinsic variability from the nuclear region. We update the known iron K lag amplitude versus black hole mass relation, and find evidence that the height or extent of the coronal source (as inferred by the reverberation time delay) increases with mass accretion rate.

  10. γ-ray variability of radio-loud narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Calderone, G.; Foschini, L.; Ghisellini, G.; Colpi, M.; Maraschi, L.; Tavecchio, F.; Decarli, R.; Tagliaferri, G.

    2011-06-01

    The recent detection of γ-ray emission from four radio-loud narrow-line Seyfert 1 galaxies suggests that the engine driving the active galactic nuclei (AGN) activity of these objects shares some similarities with that of blazars, namely the presence of a γ-ray emitting, variable jet of plasma closely aligned to the line of sight. In this work we analyse the γ-ray light curves of the four radio-loud narrow-line Seyfert 1 galaxies for which high-energy γ-ray emission has been discovered by Fermi/LAT, in order to study their variability. We find significant flux variability in all the sources. This allows us to exclude a starburst origin of the γ-ray photons and confirms the presence of a relativistic jet. Furthermore, we estimate the minimum e-folding variability time-scale (3-30 d) and infer an upper limit for the size of the emitting region (0.2-2 pc, assuming a relativistic Doppler factor δ= 10 and a jet aperture of θ= 0.1 rad).

  11. A detailed X-ray variability study of the Seyfert galaxy NGC 4051

    NASA Astrophysics Data System (ADS)

    Papadakis, I. E.; Lawrence, A.

    1995-01-01

    We present a detailed and rigorous examination of the X-ray variability characteristics of the Seyfert galaxy NGC 4051, using the 1985 EXOSAT observation and our improved power spectrum modelling techniques. The Medium Energy (ME) power spectrum is adequately fitted by a power-law model, but the Low Energy (LE) spectrum is not. We find an excellent fit by adding a broad quasi-periodic oscillation (QPO) feature on a time-scale of ~1h, which contains 1/4 of the overall variance. A similar, but much weaker, feature may exist in the ME power spectrum as well. The LE power spectrum is also clearly steeper than the ME spectrum. There is no significant lag between the ME and LE data (at most 60 s), but the cross-correlation function is noticeably asymmetric. We confirm earlier claims of a correlation between softness and flux, and show that this is essentially caused by the presence of high peaks present in the LE but not in the ME light curve. We discuss various generic models for X-ray variability. In particular, several features (especially the softness effect and the cross-correlation asymmetry) are suggestive of thermal Comptonization models. We examined one of these models in detail, with parameters suggested by recent fits to the OSSE energy spectra of Seyfert galaxies. However, this model predicts that the ME spectrum should be much steeper, in contradiction with the observed facts.

  12. 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

  13. An Extended Look at the Narrow-Line Region of the Seyfert 2 Galaxy Mrk 573

    NASA Astrophysics Data System (ADS)

    Machuca, Camilo; Fischer, Travis C.; Crenshaw, D. Michael

    2017-01-01

    Active galactic nuclei (AGN) are supermassive black holes found in the centers of galaxies which accrete matter from their surroundings and subsequently produce AGN feedback in the form of ionized and molecular gas outflows. These outflows are largely contained within the Narrow-Line Region (NLR), a low density sector that extends froms tens to thousands of parsecs away from the nucleus. In order to clarify the relationship between the AGN and its host galaxy at these various distances, we present this study on Mrk 573, a Seyfert 2 AGN, based on long-slit spectroscopy from the Dual Imaging Spectrograph (DIS) on the ARC 3.5-meter telescope at Apache Point Observatory. We find that the dominant ionization mechanism of the gas up to a radius of 2 kpc can be attributed to the AGN and that the ionized gas kinematics are dominated by galactic rotation at distances larger than 750 pc.

  14. 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.

  15. Galaxy gas as obscurer - I. GRBs x-ray galaxies and find an NH3∝ M_{star} relation

    NASA Astrophysics Data System (ADS)

    Buchner, Johannes; Schulze, Steve; Bauer, Franz E.

    2017-02-01

    An important constraint for galaxy evolution models is how much gas resides in galaxies, in particular, at the peak of star formation z = 1-3. We attempt a novel approach by letting long-duration gamma ray bursts (LGRBs) x-ray their host galaxies and deliver column densities to us. This requires a good understanding of the obscurer and biases introduced by incomplete follow-up observations. We analyse the X-ray afterglow of all 844 Swift LGRBs to date for their column density NH. To derive the population properties, we propagate all uncertainties in a consistent Bayesian methodology. The NH distribution covers the 1020-23 cm-2 range and shows no evolutionary effect. Higher obscurations, e.g. Compton-thick columns, could have been detected but are not observed. The NH distribution is consistent with sources randomly populating a ellipsoidal gas cloud of major axis {N^{major}H }=10^{23}cm^{-2} with 0.22 dex intrinsic scatter between objects. The unbiased SHOALS survey of afterglows and hosts allows us to constrain the relation between Spitzer-derived stellar masses and X-ray derived column densities NH. We find a well-constrained power-law relation of NH = 1021.7 cm-2 × (M⋆/109.5 M⊙)1/3, with 0.5 dex intrinsic scatter between objects. The Milky Way and the Magellanic clouds also follow this relation. From the geometry of the obscurer, its stellar mass dependence and comparison with local galaxies, we conclude that LGRBs are primarily obscured by galaxy-scale gas. Ray tracing of simulated Illustris galaxies reveals a relation of the same normalization, but a steeper stellar-mass dependence and mild redshift evolution. Our new approach provides valuable insight into the gas residing in high-redshift galaxies.

  16. 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.

  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. The Narrow-Line Region of Narrow-Line Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Rodríguez-Ardila, A.; Binette, Luc; Pastoriza, Miriani G.; Donzelli, Carlos J.

    2000-08-01

    This work studies the optical emission-line properties and physical conditions of the narrow-line region (NLR) of seven narrow-line Seyfert 1 galaxies (NLS1's) for which high signal-to-noise ratio spectroscopic observations were available. The resolution is 340 km s-1 (at Hα) over the wavelength interval 3700-9500 Å, enabling us to separate the broad and narrow components of the permitted emission lines. Our results show that the flux carried out by the narrow component of Hβ is, on average, 50% of the total line flux. As a result, the [O III] λ5007/Hβ ratio emitted in the NLR varies from 1 to 5, instead of the universally adopted value of 10. This has strong implications for the required spectral energy distribution that ionizes the NLR gas. Photoionization models that consider a NLR composed of a combination of matter-bounded and ionization-bounded clouds are successful at explaining the low [O III] λ5007/Hβ ratio and the weakness of low-ionization lines of NLS1's. Variation of the relative proportion of these two type of clouds nicely reproduces the dispersion of narrow-line ratios found among the NLS1 sample. Assuming similar physical model parameters of both NLS1's and the normal Seyfert 1 galaxy NGC 5548, we show that the observed differences of emission-line ratios between these two groups of galaxies can be explained, to a first approximation, in terms of the shape of the input ionizing continuum. Narrow emission-line ratios of NLS1's are better reproduced by a steep power-law continuum in the EUV-soft X-ray region, with spectral index α~-2. Flatter spectral indices (α~-1.5) match the observed line ratios of NGC 5548 but are unable to provide a good match to the NLS1 ratios. This result is consistent with ROSAT observations of NLS1's, which show that these objects are characterized by steeper power-law indices than those of Seyfert 1 galaxies with strong broad optical lines. Based on observations made at CASLEO. Complejo Astronómico El Leoncito

  19. 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

  20. GAMA/H-ATLAS: the ultraviolet spectral slope and obscuration in galaxies

    NASA Astrophysics Data System (ADS)

    Wijesinghe, D. B.; da Cunha, E.; Hopkins, A. M.; Dunne, L.; Sharp, R.; Gunawardhana, M.; Brough, S.; Sadler, E. M.; Driver, S.; Baldry, I.; Bamford, S.; Liske, J.; Loveday, J.; Norberg, P.; Peacock, J.; Popescu, C. C.; Tuffs, R.; Andrae, E.; Auld, R.; Baes, M.; Bland-Hawthorn, J.; Buttiglione, S.; Cava, A.; Cameron, E.; Conselice, C. J.; Cooray, A.; Croom, S.; Dariush, A.; Dezotti, G.; Dye, S.; Eales, S.; Frenk, C.; Fritz, J.; Hill, D.; Hopwood, R.; Ibar, E.; Ivison, R.; Jarvis, M.; Jones, D. H.; van Kampen, E.; Kelvin, L.; Kuijken, K.; Maddox, S. J.; Madore, B.; Michałowski, M. J.; Nichol, B.; Parkinson, H.; Pascale, E.; Pimbblet, K. A.; Pohlen, M.; Prescott, M.; Rhodighiero, G.; Robotham, A. S. G.; Rigby, E. E.; Seibert, M.; Sergeant, S.; Smith, D. J. B.; Temi, P.; Sutherland, W.; Taylor, E.; Thomas, D.; van der Werf, P.

    2011-08-01

    We use multiwavelength data from the Galaxy And Mass Assembly (GAMA) and Herschel-ATLAS (H-ATLAS) surveys to compare the relationship between various dust obscuration measures in galaxies. We explore the connections between the ultraviolet (UV) spectral slope, β, the Balmer decrement and the far-infrared (FIR) to 150 nm far-ultraviolet (FUV) luminosity ratio. We explore trends with galaxy mass, star formation rate (SFR) and redshift in order to identify possible systematics in these various measures. We reiterate the finding of other authors that there is a large scatter between the Balmer decrement and the β parameter, and that β may be poorly constrained when derived from only two broad passbands in the UV. We also emphasize that FUV-derived SFRs, corrected for dust obscuration using β, will be overestimated unless a modified relation between β and the attenuation factor is used. Even in the optimum case, the resulting SFRs have a significant scatter, well over an order of magnitude. While there is a stronger correlation between the IR-to-FUV luminosity ratio and β parameter than with the Balmer decrement, neither of these correlations are particularly tight, and dust corrections based on β for high-redshift galaxy SFRs must be treated with caution. We conclude with a description of the extent to which the different obscuration measures are consistent with each other as well as the effects of including other galactic properties on these correlations.

  1. Growing supermassive black holes in the late stages of galaxy mergers are heavily obscured

    NASA Astrophysics Data System (ADS)

    Ricci, C.; Bauer, F. E.; Treister, E.; Schawinski, K.; Privon, G. C.; Blecha, L.; Arevalo, P.; Armus, L.; Harrison, F.; Ho, L. C.; Iwasawa, K.; Sanders, D. B.; Stern, D.

    2017-01-01

    Mergers of galaxies are thought to cause significant gas inflows to the inner parsecs, which can activate rapid accretion onto supermassive black holes (SMBHs), giving rise to Active Galactic Nuclei (AGN). During a significant fraction of this process, SMBHs are predicted to be enshrouded by gas and dust. Studying 52 galactic nuclei in infrared-selected local Luminous and Ultra-luminous infrared galaxies in different merger stages in the hard X-ray band, where radiation is less affected by absorption, we find that the amount of material around SMBHs increases during the last phases of the merger. We find that the fraction of Compton-thick (CT, N_ H≥ 10^{24} cm^{-2}) AGN in late merger galaxies is higher (f_ CT=65^{+12}_{-13}%) than in local hard X-ray selected AGN (f CT = 27 ± 4%), and that obscuration reaches its maximum when the nuclei of the two merging galaxies are at a projected distance of D12 ≃ 0.4 - 10.8 kiloparsecs (f_ CT=77_{-17}^{+13}%). We also find that all AGN of our sample in late merger galaxies have N_ H> 10^{23} cm^{-2}, which implies that the obscuring material covers 95^{+4}_{-8}% of the X-ray source. These observations show that the material is most effectively funnelled from the galactic scale to the inner tens of parsecs during the late stages of galaxy mergers, and that the close environment of SMBHs in advanced mergers is richer in gas and dust with respect to that of SMBHs in isolated galaxies, and cannot be explained by the classical AGN unification model in which the torus is responsible for the obscuration.

  2. 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.

  3. Near-infrared Spectroscopy of Nearby Seyfert Galaxies: Is There Evidence for Shock Excitation in Narrow-line Regions?

    NASA Astrophysics Data System (ADS)

    Terao, K.; Nagao, T.; Hashimoto, T.; Yanagisawa, K.; Matsuoka, K.; Toba, Y.; Ikeda, H.; Taniguchi, Y.

    2016-12-01

    One of the important unsettled problems regarding active galactic nuclei (AGNs) is the major ionization mechanism of gas clouds in AGN narrow-line regions (NLRs). In order to investigate this issue, we present our J-band spectroscopic observations of a sample of 26 nearby Seyfert galaxies. In our study, we use the flux ratio of the following two forbidden emission lines, [Fe ii]1.257 μm and [P ii]1.188 μm, because it is known that this ratio is sensitive to the ionization mechanism. We obtain the [Fe ii]/[P ii] flux ratio or its lower limit for 19 objects. In addition to our data, we compile this flux ratio (or its lower limit) for 23 nearby Seyfert galaxies from the literature. Based on the collected data, we find that three Seyfert galaxies show very large lower limits of the [Fe ii]/[P ii] flux ratios (≳10): NGC 2782, NGC 5005, and Mrk 463. It is thus suggested that the contribution of the fast shock in the gas excitation is significantly large for them. However, more than half of the Seyfert galaxies in our sample show moderate [Fe ii]/[P ii] flux ratios (∼2), which is consistent with pure photoionization by power-law ionizing continuum emission. We also find that the [Fe ii]/[P ii] flux ratio shows no clear correlation with the radio loudness, suggesting that the radio jet is not the primary origin of shocks in NLRs of Seyfert galaxies.

  4. 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.

    2016-12-01

    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/Burst Alert Telescope nine month catalogue. 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 per cent) are extended or possibly extended and 17-25 per cent 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 per cent 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 (SF) show more extended emission (650 ± 700 pc) than active galactic nuclei (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 SF.

  5. 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.

  6. 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.

  7. 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.

  8. HUBBLE SPACE TELESCOPE MORPHOLOGIES OF z {approx} 2 DUST-OBSCURED GALAXIES. II. BUMP SOURCES

    SciTech Connect

    Bussmann, R. S.; Dey, Arjun; Lotz, J.; Jannuzi, B. T.; Armus, L.; Desai, V.; Soifer, B. T.; Brown, M. J. I.; Eisenhardt, P.; Higdon, J.; Higdon, S.; Le Floc'h, E.; Melbourne, J.; Weedman, D.

    2011-05-20

    We present Hubble Space Telescope imaging of 22 ultra-luminous infrared galaxies (ULIRGs) at z {approx} 2 with extremely red R - [24] colors (called dust-obscured galaxies, or DOGs) which have a local maximum in their spectral energy distribution (SED) at rest-frame 1.6 {mu}m associated with stellar emission. These sources, which we call 'bump DOGs', have star formation rates (SFRs) of 400-4000 M{sub sun} yr{sup -1} and have redshifts derived from mid-IR spectra which show strong polycyclic aromatic hydrocarbon emission-a sign of vigorous ongoing star formation. Using a uniform morphological analysis, we look for quantifiable differences between bump DOGs, power-law DOGs (Spitzer-selected ULIRGs with mid-IR SEDs dominated by a power law and spectral features that are more typical of obscured active galactic nuclei than starbursts), submillimeter-selected galaxies, and other less-reddened ULIRGs from the Spitzer Extragalactic First Look Survey. Bump DOGs are larger than power-law DOGs (median Petrosian radius of 8.4 {+-} 2.7 kpc versus 5.5 {+-} 2.3 kpc) and exhibit more diffuse and irregular morphologies (median M{sub 20} of -1.08 {+-} 0.05 versus -1.48 {+-} 0.05). These trends are qualitatively consistent with expectations from simulations of major mergers in which merging systems during the peak SFR period evolve from M{sub 20} = -1.0 to M{sub 20} = -1.7. Less-obscured ULIRGs (i.e., non-DOGs) tend to have more regular, centrally peaked, single-object morphologies rather than diffuse and irregular morphologies. This distinction in morphologies may imply that less-obscured ULIRGs sample the merger near the end of the peak SFR period. Alternatively, it may indicate that the intense star formation in these less-obscured ULIRGs is not the result of a recent major merger.

  9. Black hole accretion and host galaxies of obscured quasars in XMM-COSMOS

    NASA Astrophysics Data System (ADS)

    Mainieri, V.; Bongiorno, A.; Merloni, A.; Aller, M.; Carollo, M.; Iwasawa, K.; Koekemoer, A. M.; Mignoli, M.; Silverman, J. D.; Bolzonella, M.; Brusa, M.; Comastri, A.; Gilli, R.; Halliday, C.; Ilbert, O.; Lusso, E.; Salvato, M.; Vignali, C.; Zamorani, G.; Contini, T.; Kneib, J.-P.; Le Fèvre, O.; Lilly, S.; Renzini, A.; Scodeggio, M.; Balestra, I.; Bardelli, S.; Caputi, K.; Coppa, G.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Kovač, K.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Nair, P.; Pello, R.; Peng, Y.; Perez Montero, E.; Pozzetti, L.; Ricciardelli, E.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Zucca, E.; Aussel, H.; Capak, P.; Cappelluti, N.; Elvis, M.; Fiore, F.; Hasinger, G.; Impey, C.; Le Floc'h, E.; Scoville, N.; Taniguchi, Y.; Trump, J.

    2011-11-01

    Aims: We explore the connection between black hole growth at the center of obscured quasars selected from the XMM-COSMOS survey and the physical properties of their host galaxies. We study a bolometric regime ( ⟨ Lbol ⟩ = 8 × 1045 erg s-1) where several theoretical models invoke major galaxy mergers as the main fueling channel for black hole accretion. Methods: To derive robust estimates of the host galaxy properties, we use an SED fitting technique to distinguish the AGN and host galaxy emission. We evaluate the effect on galaxy properties estimates of being unable to remove the nuclear emission from the SED. The superb multi-wavelength coverage of the COSMOS field allows us to obtain reliable estimates of the total stellar masses and star formation rates (SFRs) of the hosts. We supplement this information with a morphological analysis of the ACS/HST images, optical spectroscopy, and an X-ray spectral analysis. Results: We confirm that obscured quasars mainly reside in massive galaxies (M ⋆ > 1010M⊙) and that the fraction of galaxies hosting such powerful quasars monotonically increases with the stellar mass. We stress the limitation of the use of rest-frame color - magnitude diagrams as a diagnostic tool for studying galaxy evolution and inferring the influence that AGN activity can have on such a process. We instead use the correlation between SFR and stellar mass found for star-forming galaxies to discuss the physical properties of the hosts. We find that at z ~ 1, ≈62% of Type-2 QSOs hosts are actively forming stars and that their rates are comparable to those measured for normal star-forming galaxies. The fraction of star-forming hosts increases with redshift: ≈ 71% at z ~ 2, and 100% at z ~ 3. We also find that the evolution from z ~ 1 to z ~ 3 of the specific SFR of the Type-2 QSO hosts is in excellent agreement with that measured for star-forming galaxies. From the morphological analysis, we conclude that most of the objects are bulge

  10. 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.

  11. New metallicity calibration for Seyfert 2 galaxies based on the N2O2 index

    NASA Astrophysics Data System (ADS)

    Castro, C. S.; Dors, O. L.; Cardaci, M. V.; Hägele, G. F.

    2017-01-01

    We derive a new relation between the metallicity of Seyfert 2 Active Galactic Nuclei (AGNs) and the intensity of the narrow emission-lines ratio N2O2=log([N II]λ6584/[O II]λ3727). The calibration of this relation was performed determining the metallicity (Z) of a sample of 58 AGNs through a diagram containing the observational data and the results of a grid of photoionization models obtained with the CLOUDY code. We find the new Z/Z⊙-N2O2 relation using the obtained metallicity values and the corresponding observational emission line intensities for each object of the sample. Estimations derived through the use of this new calibration indicate that narrow line regions of Seyfert 2 galaxies exhibit a large range of metallicities (0.3 ≲ Z/Z_{⊙} ≲ 2.0), with a median value Z ≈ Z⊙. Regarding the possible existence of correlations between the luminosity L(Hβ), the electron density, and the color excess E(B-V) with the metallicity in this kind of objects, we do not find correlations between them.

  12. 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.

  13. 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.

  14. The Host Galaxies of High-Luminosity Obscured Quasars at 2.5

    NASA Astrophysics Data System (ADS)

    Ross, Nicholas; Strauss, M. A.; Greene, J. E.; Zakamska, N. L.; Brandt, W. N.; Alexandroff, R.; Liu, G.; Smith, P. S.; The SDSS-III BOSS Quasar Working Group

    2014-01-01

    Active Galactic Nuclei play a key role in the evolution of galaxies. However, very little is known about the host galaxies of the most luminous quasars at redshift 2.5, the epoch when massive black hole growth peaked. The brightness of the quasar itself, which can easily outshine a galaxy by a large factor, makes it very difficult to study emission from extended gas or stars in the host galaxy. However, we have imaged the extended emission from the host galaxies of a unique sample of six optically extinguished (Type II) luminous quasars with 2.5, with the Hubble Space Telescope (Cycle 20, GO 13014) using ACS/F814W to access the rest-frame near-ultraviolet, and WFC3/F160W for the rest-frame optical longward of 4000A. These objects are selected from the spectroscopic database of the SDSS/Baryon Oscillation Spectroscopic Survey to have strong, narrow emission lines and weak continua. With these images, we have quantified the luminosity, morphology, and dynamical state of the host galaxies, and searched for extended scattered light from the obscured central engine. These observations are the first comprehensive study of both host galaxy light and scattered light in high-luminosity quasars at the epoch of maximum black hole growth, and give insights into the relationship between host galaxies and black holes during this important, and yet largely unexplored period.

  15. Strangers in Our Midst: Massive, Evolved, Highly-obscured Galaxies at z > 1

    NASA Astrophysics Data System (ADS)

    Brammer, Gabriel; 3D-HST Survey Team

    2015-01-01

    Among the most massive galaxies at z > 1, we have uncovered a significant population of galaxies with unique SEDs that are best fit with highly-obscured evolved stellar populations (log M > 11, Av > 2, age > 1 Gyr). These are not galaxies at the detection limit or galaxies with the most extreme optical-IR colors: they have always been lurking in IR-selected photometric surveys but with their redshifts significantly overestimated and subsequently-biased derived stellar population properties. Characterizing this population has previously been impossible even with medium-band near-IR photometry due to strong degeneracies between photometric redshifts and SED shapes, which we can now critically break with robust emission-line redshifts obtained from the 3D-HST grism survey (H-alpha and [OIII] at 1 < z < 2). Understanding this population is imperative for interpreting the evolution of the high-mass end of the galaxy stellar mass function. Intriguingly, these galaxies could represent an evolutionary bridge between dusty starbursts and relatively unobscured quiescent galaxies, both of which are found among massive galaxies at z > 1 but with the latter dominating at lower redshifts.

  16. An Internet Database of Ultraviolet Continuum Light Curves for Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Dunn, Jay P.; Jackson, Brian; Deo, Rajesh P.; Farrington, Chris; Das, Varendra; Crenshaw, D. Michael

    2006-04-01

    Using the Multimission Archive at STScI (MAST), we have extracted spectra and determined continuum light curves for 175 Seyfert galaxies that have been observed with the International Ultraviolet Explorer and the Faint Object Spectrograph on the Hubble Space Telescope. To obtain the light curves as a function of Julian Date, we used fixed bins in the object's rest frame and measured small regions (between 30 and 60 Å) of each spectrum's continuum flux in the range 1150 to 3200 Å. We provide access to the UV light curves and other basic information about the observations in tabular and graphical form via the Internet at http://www.chara.gsu.edu/PEGA/IUE.

  17. 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.

  18. 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).

  19. 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.

  20. 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.

  1. REVERBERATION MAPPING MEASUREMENTS OF BLACK HOLE MASSES IN SIX LOCAL SEYFERT GALAXIES

    SciTech Connect

    Denney, K. D.; Peterson, B. M.; Pogge, R. W.; Atlee, D. W.; Bentz, M. C.; Bird, J. C.; Comins, M. L.; Dietrich, M.; Eastman, J. D.; Adair, A.; Au-Yong, K.; Chisholm, E.; Ewald, S.; Ferbey, S.; Jackson, K.; Brokofsky, D. J.; Gaskell, C. M.; Hedrick, C. H.; Doroshenko, V. T.

    2010-09-20

    We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved H{beta} reverberation lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and H{beta} emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) R{sub BLR}-L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved H{beta} time-delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.

  2. Narrow line Seyfert 1 galaxies: where are the broad line regions?

    NASA Astrophysics Data System (ADS)

    Mao, Weiming; Hu, Chen; Wang, Jianmin; Bian, Weihao; Zhang, Shu; Zhao, Gang

    2010-12-01

    A sample consisting of 211 narrow line Seyfert 1 galaxies (NLS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the H β profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined H β reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

  3. 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

  4. 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.

  5. THE LINK BETWEEN THE HIDDEN BROAD LINE REGION AND THE ACCRETION RATE IN SEYFERT 2 GALAXIES

    SciTech Connect

    Marinucci, Andrea; Bianchi, Stefano; Matt, Giorgio; Nicastro, Fabrizio; Goulding, Andy D.

    2012-04-01

    In the past few years, more and more pieces of evidence have been presented for a revision of the widely accepted unified model of active galactic nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In the following, we will present evidence that accretion rate is also a key parameter for the presence of hidden broad line regions (HBLRs) in Seyfert 2 galaxies. Our sample consists of 21 sources with polarized hidden broad lines and 18 sources without hidden broad lines. We use stellar velocity dispersions from several studies on the Ca II and Mg b triplets in Seyfert 2 galaxies to estimate the mass of the central black holes via the M{sub BH}-{sigma}{sub *} relation. The ratio between the bolometric luminosity, derived from the intrinsic (i.e., unabsorbed) X-ray luminosity, and the Eddington luminosity is a measure of the rate at which matter accretes onto the central supermassive black hole. A separation between Compton-thin HBLR and non-HBLR sources is clear, both in accretion rate (log L{sub bol}/L{sub Edd} = -1.9) and in luminosity (log L{sub bol} = 43.90). When properly luminosity-corrected Compton-thick sources are included, the separation between HBLR and non-HBLR is less sharp but no HBLR source falls below the Eddington ratio threshold. We speculate that non-HBLR Compton-thick sources with accretion rate higher than the threshold do possess a BLR, but something, probably related to their heavy absorption, is preventing us from observing it even in polarized light. Our results for Compton-thin sources support theoretical expectations. In a model presented by Nicastro, the presence of broad emission lines is intrinsically connected with disk instabilities occurring in proximity of a transition radius, which is a function of the accretion rate, becoming smaller than the innermost stable orbit for very low accretion rates and therefore luminosities.

  6. The Link between the Hidden Broad Line Region and the Accretion Rate in Seyfert 2 Galaxies

    NASA Astrophysics Data System (ADS)

    Marinucci, Andrea; Bianchi, Stefano; Nicastro, Fabrizio; Matt, Giorgio; Goulding, Andy D.

    2012-04-01

    In the past few years, more and more pieces of evidence have been presented for a revision of the widely accepted unified model of active galactic nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In the following, we will present evidence that accretion rate is also a key parameter for the presence of hidden broad line regions (HBLRs) in Seyfert 2 galaxies. Our sample consists of 21 sources with polarized hidden broad lines and 18 sources without hidden broad lines. We use stellar velocity dispersions from several studies on the Ca II and Mg b triplets in Seyfert 2 galaxies to estimate the mass of the central black holes via the M BH-σsstarf relation. The ratio between the bolometric luminosity, derived from the intrinsic (i.e., unabsorbed) X-ray luminosity, and the Eddington luminosity is a measure of the rate at which matter accretes onto the central supermassive black hole. A separation between Compton-thin HBLR and non-HBLR sources is clear, both in accretion rate (log L bol/L Edd = -1.9) and in luminosity (log L bol = 43.90). When properly luminosity-corrected Compton-thick sources are included, the separation between HBLR and non-HBLR is less sharp but no HBLR source falls below the Eddington ratio threshold. We speculate that non-HBLR Compton-thick sources with accretion rate higher than the threshold do possess a BLR, but something, probably related to their heavy absorption, is preventing us from observing it even in polarized light. Our results for Compton-thin sources support theoretical expectations. In a model presented by Nicastro, the presence of broad emission lines is intrinsically connected with disk instabilities occurring in proximity of a transition radius, which is a function of the accretion rate, becoming smaller than the innermost stable orbit for very low accretion rates and therefore luminosities.

  7. Investigating the dusty torus of Seyfert galaxies using SOFIA/FORCAST photometry

    NASA Astrophysics Data System (ADS)

    Fuller, L.; Lopez-Rodriguez, E.; Packham, C.; Ramos-Almeida, C.; Alonso-Herrero, A.; Levenson, N. A.; Radomski, J.; Ichikawa, K.; García-Bernete, I.; González-Martín, O.; Díaz-Santos, T.; Martínez-Paredes, M.

    2016-11-01

    We present 31.5 μm imaging photometry of 11 nearby Seyfert galaxies observed from the Stratospheric Observatory For Infrared Astronomy (SOFIA) using the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST). We tentatively detect extended 31 μm emission for the first time in our sample. In combination with this new data set, subarcsecond resolution 1-18 μm imaging and 7.5-13 μm spectroscopic observations were used to compute the nuclear spectral energy distribution (SED) of each galaxy. We found that the turnover of the torus emission does not occur at wavelengths ≤31.5 μm, which we interpret as a lower-limit for the wavelength of peak emission. We used CLUMPY torus models to fit the nuclear infrared (IR) SED and infer trends in the physical parameters of the AGN torus for the galaxies in the sample. Including the 31.5 μm nuclear flux in the SED (1) reduces the number of clumpy torus models compatible with the data, and (2) modifies the model output for the outer radial extent of the torus for 10 of the 11 objects. Specifically, six (60 per cent) objects show a decrease in radial extent while four (40 per cent) show an increase. We find torus outer radii ranging from <1 to 8.4 pc.

  8. 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.

  9. HEAVILY OBSCURED AGN IN STAR-FORMING GALAXIES AT z approx = 2

    SciTech Connect

    Treister, E.; Kartaltepe, Jeyhan; Le Floc'h, Emeric; Cardamone, Carolin N.; Schawinski, Kevin; Urry, C. Megan; Virani, Shanil; Gawiser, Eric; Lira, Paulina; Damen, Maaike; Taylor, Edward N.; Justham, Stephen; Koekemoer, Anton M.

    2009-11-20

    We study the properties of a sample of 211 heavily obscured active galactic nucleus (AGN) candidates in the extended Chandra Deep Field-South selecting objects with f {sub 24m}u{sub m}/f{sub R} > 1000 and R - K>4.5. Of these, 18 were detected in X-rays and found to be obscured AGNs with neutral hydrogen column densities of approx10{sup 23} cm{sup -2}. In the X-ray-undetected sample, the following evidence suggests a large fraction of heavily obscured (Compton-thick) AGN: (1) The stacked X-ray signal of the sample is strong, with an observed ratio of soft to hard X-ray counts consistent with a population of approx90% heavily obscured AGNs combined with 10% star-forming galaxies. (2) The X-ray-to-mid-IR ratios for these sources are significantly larger than that of star-forming galaxies and approx2 orders of magnitude smaller than for the general AGN population, suggesting column densities of N {sub H} approx> 5 x 10{sup 24} cm{sup -2}. (3) The Spitzer near- and mid-IR colors of these sources are consistent with those of the X-ray-detected samples if the effects of dust self-absorption are considered. Spectral fitting to the rest-frame UV/optical light (dominated by the host galaxy) returns stellar masses of approx10{sup 11} M{sub sun} and (E(B - V)) = 0.5, and reveals evidence for a significant young stellar population, indicating that these sources are experiencing considerable star formation. This sample of heavily obscured AGN candidates implies a space density at z approx 2 of approx10{sup -5} Mpc{sup -3}, finding a strong evolution in the number of L{sub X} >10{sup 44} erg s{sup -1} sources from z = 1.5 to 2.5, possibly consistent with a short-lived heavily obscured phase before an unobscured quasar is visible.

  10. Hot Dust Obscured Galaxies with Excess Blue Light: Dual AGN or Single AGN Under Extreme Conditions?

    NASA Astrophysics Data System (ADS)

    Assef, R. J.; Walton, D. J.; Brightman, M.; Stern, D.; Alexander, D.; Bauer, F.; Blain, A. W.; Diaz-Santos, T.; Eisenhardt, P. R. M.; Finkelstein, S. L.; Hickox, R. C.; Tsai, C.-W.; Wu, J. W.

    2016-03-01

    Hot dust-obscured galaxies (Hot DOGs) are a population of hyper-luminous infrared galaxies identified by the Wide-field Infrared Survey Explorer (WISE) mission from their very red mid-IR colors, and characterized by hot dust temperatures (T > 60 K). Several studies have shown clear evidence that the IR emission in these objects is powered by a highly dust-obscured active galactic nucleus (AGN) that shows close to Compton-thick absorption at X-ray wavelengths. Thanks to the high AGN obscuration, the host galaxy is easily observable, and has UV/optical colors usually consistent with those of a normal galaxy. Here we discuss a sub-population of eight Hot DOGs that show enhanced rest-frame UV/optical emission. We discuss three scenarios that might explain the excess UV emission: (i) unobscured light leaked from the AGN by reflection over the dust or by partial coverage of the accretion disk; (ii) a second unobscured AGN in the system; or (iii) a luminous young starburst. X-ray observations can help discriminate between these scenarios. We study in detail the blue excess Hot DOG WISE J020446.13-050640.8, which was serendipitously observed by Chandra/ACIS-I for 174.5 ks. The X-ray spectrum is consistent with a single, hyper-luminous, highly absorbed AGN, and is strongly inconsistent with the presence of a secondary unobscured AGN. Based on this, we argue that the excess blue emission in this object is most likely either due to reflection or a co-eval starburst. We favor the reflection scenario as the unobscured star formation rate needed to power the UV/optical emission would be ≳1000 M⊙ yr-1. Deep polarimetry observations could confirm the reflection hypothesis.

  11. HOT DUST OBSCURED GALAXIES WITH EXCESS BLUE LIGHT: DUAL AGN OR SINGLE AGN UNDER EXTREME CONDITIONS?

    SciTech Connect

    Assef, R. J.; Diaz-Santos, T.; Walton, D. J.; Brightman, M.; Stern, D.; Eisenhardt, P. R. M.; Tsai, C.-W.; Alexander, D.; Bauer, F.; Blain, A. W.; Finkelstein, S. L.; Hickox, R. C.; Wu, J. W.

    2016-03-10

    Hot dust-obscured galaxies (Hot DOGs) are a population of hyper-luminous infrared galaxies identified by the Wide-field Infrared Survey Explorer (WISE) mission from their very red mid-IR colors, and characterized by hot dust temperatures (T > 60 K). Several studies have shown clear evidence that the IR emission in these objects is powered by a highly dust-obscured active galactic nucleus (AGN) that shows close to Compton-thick absorption at X-ray wavelengths. Thanks to the high AGN obscuration, the host galaxy is easily observable, and has UV/optical colors usually consistent with those of a normal galaxy. Here we discuss a sub-population of eight Hot DOGs that show enhanced rest-frame UV/optical emission. We discuss three scenarios that might explain the excess UV emission: (i) unobscured light leaked from the AGN by reflection over the dust or by partial coverage of the accretion disk; (ii) a second unobscured AGN in the system; or (iii) a luminous young starburst. X-ray observations can help discriminate between these scenarios. We study in detail the blue excess Hot DOG WISE J020446.13–050640.8, which was serendipitously observed by Chandra/ACIS-I for 174.5 ks. The X-ray spectrum is consistent with a single, hyper-luminous, highly absorbed AGN, and is strongly inconsistent with the presence of a secondary unobscured AGN. Based on this, we argue that the excess blue emission in this object is most likely either due to reflection or a co-eval starburst. We favor the reflection scenario as the unobscured star formation rate needed to power the UV/optical emission would be ≳1000 M{sub ⊙} yr{sup −1}. Deep polarimetry observations could confirm the reflection hypothesis.

  12. 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.

  13. 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.

  14. Radiation mechanisms and physical properties of the γ-ray narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Yang, Jianping; Zhou, Bing

    2015-12-01

    We investigate the physical properties and radiation mechanisms of 11 states of five narrow-line Seyfert 1 (NLS1) galaxies detected by the Large Area Telescope on board Fermi through modeling the quasi-simultaneous multi-band observations. We obtain the best-fitting model parameters and their uncertainties for each state with the χ2-minimization procedure and discuss their implications on the characteristics of jet. Similar to blazars, their spectral energy distributions (SEDs) have a two-humped structure and their non-thermal emission can be modelled with the single-zone synchrotron + inverse Compton (IC) model. For all states, the GeV γ-rays may be contributed by the external Compton (EC) emission components. The observations of Fermi are mostly located at the declining stage of the EC humps. Text < 0.5 eV in all cases (Text is the characteristic temperature of external soft photons), suggesting that their radiation zones may be usually located outside of the broad line region (BLR) and the soft photons of Compton scattering mainly come from the dust torus. Compared with the bright Fermi blazars studied by Ghisellini et al. (2014, Nature, 515, 376), the Pjet (the power of the jets) of NLS1 galaxies detected by Fermi is similar to that of the flat spectrum radio quasars (FSRQs) but a little larger than that of the BL Lac objects (BL Lacs). However, a comparison of Pr (the powers of radiations) with the FSRQs and BL Lac objects shows that NLS1 galaxies' Pr has values comparable to BL Lac objects but lower than FSRQs in spite of having similar Pjet values and the same energy carrier (the cold protons) as the FSRQs. Observations indicate that γ-NLS1 galaxies might have lower η (efficiency of gravitational energy release) values than GeV blazars.

  15. 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.

  16. Fe–K LINE TIME VARIABILITY AND Ni ABUNDANCE OF DISTANT REFLECTORS IN SEYFERT GALAXIES

    SciTech Connect

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

    2016-04-10

    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.

  17. 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.

  18. Narrow-Line Seyfert 1 Galaxies and their place in the Universe

    NASA Astrophysics Data System (ADS)

    Foschini, L.; Colpi, M.; Gallo, L.; Grupe, D.; Komossa, S.; Leighly, K.; Mathur, S.

    In 1978, Davidson and Kinman wrote about Markarian 359: "This unusual object merits further observations...". In 1985, Osterbrock and Pogge defined a new class of active galactic nuclei (AGN), named Narrow-Line Seyfert 1 (NLS1). Twenty-five years later, NLS1s still continue to intrigue and bewilder. NLS1s manifest extreme behaviour at all wavelengths. They exhibit the most extreme X-ray variability seen in radio-quiet AGN, the most intense optical FeII emission, and high rates of star formation. In general, their characteristics are consistent of AGNs with relatively low mass black holes accreting close to the Eddington rate. The 2009 Fermi Gamma-ray Space Telescope discovery of high-energy (E>100 MeV) gamma rays in a handful of NLS1s has established the existence of relativistic jets in these systems -- a fact previously hinted at by the flat radio spectrum and high brightness temperature seen in some objects. Since NLS1 are generally hosted by spirals, this poses some intriguing questions on the galaxy evolution and on how relativistic jets are generated. It is therefore time for the broad community to come together and discuss what we have discovered in the last quarter century and lay the foundation for future work. Workshop Topics: * Central engine: BH mass, accretion disk, BLR/NLR, jet * Host galaxy: morphology, star formation, merging history * NLS1 in the Universe: comparison with other types of AGN, surveys/statistics, formation/merging, cosmological evolution

  19. A Low-mass Black Hole in the Nearby Seyfert Galaxy UGC 06728

    NASA Astrophysics Data System (ADS)

    Bentz, Misty C.; Batiste, Merida; Seals, James; Garcia, Karen; Kuzio de Naray, Rachel; Peters, Wesley; Anderson, Matthew D.; Jones, Jeremy; Lester, Kathryn; Machuca, Camilo; Parks, J. Robert; Pope, Crystal L.; Revalski, Mitchell; Roberts, Caroline A.; Saylor, Dicy; Sevrinsky, R. Andrew; Turner, Clay

    2016-11-01

    We present the results of a recent reverberation mapping campaign for UGC 06728, a nearby low-luminosity Seyfert 1 in a late-type galaxy. Nightly monitoring in the spring of 2015 allowed us to determine an Hβ time delay of τ =1.4+/- 0.8 days. Combined with the width of the variable Hβ line profile, we determine a black hole mass of {M}{BH}=(7.1+/- 4.0)× {10}5 {M}⊙ . We also constrain the bulge stellar velocity dispersion from higher-resolution long-slit spectroscopy along the galaxy minor axis and find {σ }\\star =51.6+/- 4.9 km s-1. The measurements presented here are in good agreement with both the {R}{BLR}{--}L relationship and the {M}{BH}{--}{σ }\\star relationship for active galactic nuclei. Combined with a previously published spin measurement, our mass determination for UGC 06728 makes it the lowest-mass black hole that has been fully characterized, and thus an important object to help anchor the low-mass end of black hole evolutionary models.

  20. 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.

  1. A Fanaroff-Riley Type I Candidate in Narrow-Line Seyfert 1 Galaxy Mrk 1239

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

  2. The Molecular Wind in the Nearest Seyfert Galaxy Circinus Revealed by ALMA

    NASA Astrophysics Data System (ADS)

    Zschaechner, Laura K.; Walter, Fabian; Bolatto, Alberto; Farina, Emanuele P.; Kruijssen, J. M. Diederik; Leroy, Adam; Meier, David S.; Ott, Jürgen; Veilleux, Sylvain

    2016-12-01

    We present ALMA observations of the inner 1‧ (1.2 kpc) of the Circinus galaxy, the nearest Seyfert. We target CO (1-0) in the region associated with a well-known multiphase outflow driven by the central active galactic nucleus (AGN). While the geometry of Circinus and its outflow make disentangling the latter difficult, we see indications of outflowing molecular gas at velocities consistent with the ionized outflow. We constrain the mass of the outflowing molecular gas to be 1.5 × 105-5.1 × 106 M ⊙, yielding a molecular outflow rate of 0.35-12.3 M ⊙ yr-1. The values within this range are comparable to the star formation (SF) rate in Circinus, indicating that the outflow indeed regulates SF to some degree. The molecular outflow in Circinus is considerably lower in mass and energetics than previously studied AGN-driven outflows, especially given its high ratio of AGN luminosity to bolometric luminosity. The molecular outflow in Circinus is, however, consistent with some trends put forth by Cicone et al., including a linear relation between kinetic power and AGN luminosity, as well as its momentum rate versus bolometric luminosity (although the latter places Circinus among the starburst galaxies in that sample). We detect additional molecular species including CN and C17O.

  3. Obscured active galactic nuclei triggered in compact star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Yen; Le Floc'h, Emeric; Juneau, Stéphanie; da Cunha, Elisabete; Salvato, Mara; Civano, Francesca; Marchesi, Stefano; Gabor, J. M.; Ilbert, Olivier; Laigle, Clotilde; McCracken, H. J.; Hsieh, Bau-Ching; Capak, Peter

    2017-03-01

    We present a structural study of 182 obscured active galactic nuclei (AGNs) at z ≤ 1.5, selected in the Cosmic Evolution Survey field from their extreme infrared to X-ray luminosity ratio and their negligible emission at optical wavelengths. We fit optical to far-infrared spectral energy distributions and analyse deep Hubble Space Telescope imaging to derive the physical and morphological properties of their host galaxies. We find that such galaxies are more compact than normal star-forming sources at similar redshift and stellar mass, and we show that it is not an observational bias related to the emission of the AGN. Based on the distribution of their UVJ colours, we also argue that this increased compactness is not due to the additional contribution of a passive bulge. We thus postulate that a vast majority of obscured AGNs reside in galaxies undergoing dynamical compaction, similar to processes recently invoked to explain the formation of compact star-forming sources at high redshift.

  4. DUST PROPERTIES OF LOCAL DUST-OBSCURED GALAXIES WITH THE SUBMILLIMETER ARRAY

    SciTech Connect

    Hwang, Ho Seong; Andrews, Sean M.; Geller, Margaret J. E-mail: sandrews@cfa.harvard.edu

    2013-11-01

    We report Submillimeter Array observations of the 880 μm dust continuum emission for four dust-obscured galaxies (DOGs) in the local universe. Two DOGs are clearly detected with S{sub ν}(880 μm) =10-13 mJy and S/N > 5, but the other two are not detected with 3σ upper limits of S{sub ν}(880 μm) =5-9 mJy. Including an additional two local DOGs with submillimeter data from the literature, we determine the dust masses and temperatures for six local DOGs. The infrared luminosities and dust masses for these DOGs are in the ranges of 1.2-4.9 × 10{sup 11}(L{sub ☉}) and 4-14 × 10{sup 7}(M{sub ☉}), respectively. The dust temperatures derived from a two-component modified blackbody function are 23-26 K and 60-124 K for the cold and warm dust components, respectively. Comparison of local DOGs with other infrared luminous galaxies with submillimeter detections shows that the dust temperatures and masses do not differ significantly among these objects. Thus, as argued previously, local DOGs are not a distinctive population among dusty galaxies, but simply represent the high-end tail of the dust obscuration distribution.

  5. Gamma-ray emitting narrow-line Seyfert 1 galaxies and their place in the AGN zoo

    NASA Astrophysics Data System (ADS)

    D'Ammando, Filippo; Orienti, Monica; Finke, Justin; Giroletti, Marcello; Larsson, Josefin

    2016-08-01

    Relativistic jets are usually produced by radio-loud AGN hosted in giant elliptical galaxies such as blazars and radio galaxies. The discovery by Fermi-LAT of variable gamma-ray emission from narrow-line Seyfert 1 (NLSy1) galaxies revealed the presence of a new class of AGN with relativistic jets. Considering that NLSy1 are usually hosted in spiral galaxies, this finding poses intriguing questions about the nature of these objects and the formation of relativistic jets. In this talk I discuss the radio-to-gamma-ray properties of the gamma-ray NLSy1 detected during the first 7 years of Fermi operation, the observations of their host galaxies, and the estimation of their black hole masses.

  6. Obscuration, orientation, and the infrared properties of radio-loud active galaxies

    NASA Technical Reports Server (NTRS)

    Heckman, Timothy M.; O'Dea, Christopher P.; Baum, Stefi A.; Laurikainen, Eija

    1994-01-01

    We report on a study of the mid- and far-infrared (MFIR) properties of several different classes of radio-loud active galactic nuclei (AGNs) using the IRAS database. Our goal is to try to improve the understanding of the possible relationships between the diverse classes of AGNs. The MFIR and radio properties of radio-loud AGNs are especially useful in this regard, since (excluding the blazar class, which we do not study here) the radio emission is thought to be emitted isotropically, and the radio and MFIR radiation should be much less affected by dust obscuration than radiation at shorter wavelengths. We have first compared samples of 3CR broad-line radio galaxies (BLRGs) and narrow-line radio galaxies (NLRGs) matched in radio flux and mean redshift. We find that the BLRGs are stronger than the NLRGs by a factor of 4-5 in their mid-IR emission but are similar to the NLRGs in the far-IR. This is qualitatively consistent with recent 'unification' models for NLRGs and BLRGs which invoke thermal MFIR emission from dusty 'obscuring tori,' but there may be an additional source of far-IR emission present in the more luminous broad-line objects (the radio-loud quasars) studied previously by Heckman, Chambers & Postman (1992). We have also compared samples of Fanaroff-Riley class I (FRI) and Fanaroff-Riley class II (FRII) radio galaxies matched in radio flux and redshift. The FRII galaxies are stronger MFIR emitters than the FRI galaxies by a factor of about 4. This is consistent with suggestions that the central engine in FRI galaxies produces relatively little radiant energy per unit jet power (expecially since we find that the weak MFIR emission from the FRI galaxies may not be powered by the AGN). Comparing samples of gigahertz-peaked spectrum (GPS) and compact steep spectrum (CSS) sources versus non-GPS-CSS sources, we find that the GPS-CSS and non-GPS-CSS sources have similar MFIR strengths. This suggests that the efficiency of the conversion of jet kinetic energy

  7. 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.

  8. Broad-line Reverberation in the Kepler-field Seyfert Galaxy Zw 229-015

    NASA Astrophysics Data System (ADS)

    Barth, Aaron J.; Nguyen, My L.; Malkan, Matthew A.; Filippenko, Alexei V.; Li, Weidong; Gorjian, Varoujan; Joner, Michael D.; Bennert, Vardha Nicola; Botyanszki, Janos; Cenko, S. Bradley; Childress, Michael; Choi, Jieun; Comerford, Julia M.; Cucciara, Antonino; da Silva, Robert; Duchêne, Gaspard; Fumagalli, Michele; Ganeshalingam, Mohan; Gates, Elinor L.; Gerke, Brian F.; Griffith, Christopher V.; Harris, Chelsea; Hintz, Eric G.; Hsiao, Eric; Kandrashoff, Michael T.; Keel, William C.; Kirkman, David; Kleiser, Io K. W.; Laney, C. David; Lee, Jeffrey; Lopez, Liliana; Lowe, Thomas B.; Moody, J. Ward; Morton, Alekzandir; Nierenberg, A. M.; Nugent, Peter; Pancoast, Anna; Rex, Jacob; Rich, R. Michael; Silverman, Jeffrey M.; Smith, Graeme H.; Sonnenfeld, Alessandro; Suzuki, Nao; Tytler, David; Walsh, Jonelle L.; Woo, Jong-Hak; Yang, Yizhe; Zeisse, Carl

    2011-05-01

    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 Hβ 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 Hβ flux. From cross-correlation measurements, we find that the Hβ light curve has a rest-frame lag of 3.86+0.69 -0.90 days with respect to the V-band continuum variations. We also measure reverberation lags for Hα and Hγ and find an upper limit to the Hδ lag. Combining the Hβ lag measurement with a broad Hβ width of σline = 1590 ± 47 km s-1 measured from the rms variability spectrum, we obtain a virial estimate of M BH = 1.00+0.19 -0.24 × 107 M 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.

  9. 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.

  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. 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.

  12. HEAVY DUST OBSCURATION OF z = 7 GALAXIES IN A COSMOLOGICAL HYDRODYNAMIC SIMULATION

    SciTech Connect

    Kimm, Taysun; Cen, Renyue

    2013-10-10

    Hubble Space Telescope observations with the Wide Field Camera 3/Infrared reveal that galaxies at z ∼ 7 have very blue ultraviolet (UV) colors, consistent with these systems being dominated by young stellar populations with moderate or little attenuation by dust. We investigate UV and optical properties of the high-z galaxies in the standard cold dark matter model using a high-resolution adaptive mesh refinement cosmological hydrodynamic simulation. For this purpose, we perform panchromatic three-dimensional dust radiative transfer calculations on 198 galaxies of stellar mass 5 × 10{sup 8}-3 × 10{sup 10} M{sub ☉} with three parameters: the dust-to-metal ratio, the extinction curve, and the fraction of directly escaped light from stars (f{sub esc}). Our stellar mass function is found to be in broad agreement with Gonzalez et al., independent of these parameters. We find that our heavily dust-attenuated galaxies (A{sub V} ∼ 1.8) can also reasonably match modest UV-optical colors, blue UV slopes, as well as UV luminosity functions, provided that a significant fraction (∼10%) of light directly escapes from them. The observed UV slope and scatter are better explained with a Small-Magellanic-Cloud-type extinction curve, whereas a Milky-Way-type curve also predicts blue UV colors due to the 2175 Å bump. We expect that upcoming observations by the Atacama Large Millimeter/submillimeter Array will be able to test this heavily obscured model.

  13. 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.

  14. 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.

  15. ROSAT Position Sensitive Proportional Counter spectra of six Seyfert 1 galaxies

    NASA Technical Reports Server (NTRS)

    Turner, T. J.; George, I. M.; Mushotzky, R. F.

    1993-01-01

    We present the results from ROSAT Position Sensitive Proportional Counter observations of six Seyfert 1 galaxies in the soft (0.1-2.0 keV) X-ray band. The sources (Mrk 335, ESO 198-G24, ESO 141-G55, Mrk 509, NGC 7469, and MCG-2-58-22) were chosen to have low absorbing column densities along the line of sight. As expected, it is found that all the sources possess significantly steeper spectra below about 1 keV than observed at higher X-ray energies. Assuming a simple absorbed power-law spectral model, the mean (photon) spectral index for the sample is Gamma = 2.38 +/- 0.25, compared to the canonical 1.7 typically observed in the 2-10 keV band. Furthermore, we find strong evidence for soft X-ray spectral features in half the sources. In NGC 7469 and ESO 198-G24, we find that the addition of a narrow emission line or an absorption edge to the underlying continuum is a significant improvement to the parameterization of the spectra. Mrk 335 also shows evidence for spectral complexity, but from these data it is not possible to unambiguously distinguish between an absorption edge and a steepening of the spectrum at low energies. We examine these results in the light of the accuracy of the PSPC spectral calibration.

  16. The Role of AGN Feedback in the Evolution of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Mueller-Sanchez, F.; Malkan, M.; Hicks, E.; Davies, R.

    2014-10-01

    Adaptive optics integral-field observations of Seyfert Galaxies have recently revealed clear evidence of AGN-driven outflows of ionized gas. By resolving the inner 10-20 parsecs, we are successfully modeling the geometry and kinematics of the outflows in 3D. The model parameters are used to estimate mechanical feedback from the AGN and test unification models. The mass outflow rates are 2-3 orders of magnitude greater than the accretion rates, but they are comparable to the estimated inflow rates to the central 10-25 pc, suggesting that the outflows may remove a considerable amount of the infalling gas before it reaches the accretion disk. The outflows seem to form two distinct groups which differ by outflow power variations with radio flux. While powerful outflows (with kinetic powers > 1.0% Lbol) are observed in objects with extended radio jets, in the other AGN - in which the outflow power is less than 0.1% Lbol - the radio jet is weak and compact.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Deep X-ray spectroscopy and imaging of the Seyfert 2 galaxy, ESO 138-G001

    NASA Astrophysics Data System (ADS)

    De Cicco, M.; Marinucci, A.; Bianchi, S.; Piconcelli, E.; Violino, G.; Vignali, C.; Nicastro, F.

    2015-10-01

    We present a spectral and imaging analysis of the XMM-Newton and Chandra observations of the Seyfert 2 galaxy ESO138-G001, with the aim of characterizing the circumnuclear material responsible for the soft (0.3-2.0 keV) and hard (5-10 keV) X-ray emission. We confirm that the source is absorbed by Compton-thick gas. However, if a self-consistent model of reprocessing from cold toroidal material is used (MYTORUS), a possible scenario requires the absorber to be inhomogenous, its column density along the line of sight being larger than the average column density integrated over all lines of sight through the torus. The iron emission line may be produced by moderately ionized iron (Fe XII-Fe XIII), as suggested by the shifted centroid energy and the low K β/K α flux ratio. The soft X-ray emission is dominated by emission features, whose main excitation mechanism appears to be photoionization, as confirmed by line diagnostics and the use of self-consistent models (CLOUDY).

  7. Stellar and ionized gas kinematics of the interacting Seyfert 1.9 galaxy NGC 2992

    NASA Astrophysics Data System (ADS)

    García-Lorenzo, B.; Arribas, S.; Mediavilla, E.

    2001-11-01

    Integral field spectroscopy in the central 16''x 12'' (2.4 kpc x 1.8 kpc, if H0 = 75 km s-1 Mpc-1) of the Seyfert 1.9 galaxy NGC 2992 has been obtained using the fibre system INTEGRAL. The data are mainly used to study the stellar and ionized gas kinematics. In spite of the photometric disruptions in the outer parts (r > 6 kpc) produced by the interaction with its close companion (NGC 2993), the present stellar velocity field shows regular rotation. The ionized gas presents several kinematically distinct components. Apart from the outflowing component already reported by other authors, we found an additional (high ionization) kinematic component which seems to be associated with the boundaries of the figure-of-eight-shaped emission detected in the 6 cm radio map. We locate the hidden nucleus in the apex of the biconical structure defined by the [O iii] emission, coincident with the outflow origin and with the center of the dust lane. We do not find any clear evidence of direct influence of the interaction in the kinematics of the stars or the ionized gas in the circumnuclear region of NGC 2992.

  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. THE COMPACT RADIO STRUCTURE OF RADIO-LOUD NARROW LINE SEYFERT 1 GALAXIES

    SciTech Connect

    Gu Minfeng; Chen Yongjun

    2010-06-15

    We present the compact radio structure of three radio-loud narrow line Seyfert 1 galaxies from the Very Long Baseline Array archive data at 2.3, 5, and 8.4 GHz. In RXS J16290+4007, the radio structure is mostly unresolved. The combination of compact radio structure, high brightness temperature, and inverted spectrum between simultaneous 2.3 and 8.4 GHz strongly favors jet relativistic beaming. Combined with the very long baseline interferometry data at 1.6 and 8.4 GHz from the literature, we argue that RXS J16333+4718 also may harbor a relativistic jet, with resolved core-jet structure in 5 GHz. B3 1702+457 is clearly resolved with a well-defined jet component. The overall radio steep spectrum indicates that B3 1702+457 is likely a source optically defined as NLS1 with radio definition of compact steep spectrum sources. From these three sources, we found that radio loud NLS1s can be either intrinsically radio loud (e.g., B3 1702+457) or apparently radio loud due to jet beaming effects (e.g., RXS J16290+4007 and RXS J16333+4718).

  10. Coevolution of supermassive black holes and circumnuclear dense molecular gas disk in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Izumi, T.

    2015-09-01

    The energy emitted by an active galactic nucleus (AGN) is commonly ascribed to mass accretion onto a supermassive black hole (SMBH). However, the physics of angular momentum transfer at r < 100 pc from the SMBH is still unclear. Interestingly, recent high resolution IR observations suggest a possible connection between a circumnuclear (i.e., < 100 pc scale) star formation rate and a mass accretion rate onto a SMBH (e.g., Esquej et al. 2014). But to study such a tentative AGN-starburst connection in detail, it is also necessary to investigate properties of circumnuclear molecular gas, because such gas is the site of massive star formation, and also be the fuel for AGNs. Therefore, we compiled interferometric data of the 100 pc scale circumnuclear molecular gas disk (CND) in nearby Seyfert galaxies, and found a (tentative) correlation between (1) a ratio of the mass of the CND and the mass of the SMBH and (2) a mass accretion rate onto the SMBH. The mass of the CND is estimated by using HCN(1-0) emission line, which is a typical tracer of dense molecular gas (unlike J=1-0 CO). This correlation can be expected in a turbulent disk

  11. X-ray Fluctuation Power Spectral Density Survey of Six Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Markowitz, A.

    2002-05-01

    By combining low-density RXTE long- and medium-term monitoring with high-density, short-term monitoring from XMM and Chandra long-looks, we have constructed X-ray fluctuation power spectral densities (PSDs) for six Seyfert 1 galaxies. These PSDs cover unprecedented dynamic ranges, continuously spanning up to or beyond 4 orders of magnitude in temporal frequency. The PSDs of four targets show significant flattening towards lower frequencies and bear remarkable similarity to X-ray Binary PSDs, strengthening the argument that similar emission processes occur in both types of compact accreting systems, spanning a factor of ~106-7 in luminosity and putative black hole mass. Assuming a linear mass-timescale relation, the resulting PSD break frequencies imply black hole masses which generally agree with reverberation-mapped mass estimates. If the geometric origin of the variability is close to the X-ray corona, then the physical timescales associated with thermal and acoustic disk variations may be relevant.

  12. THE RADIO PROPERTIES OF RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES ON PARSEC SCALES

    SciTech Connect

    Gu, Minfeng; Chen, Yongjun; Shen, Zhiqiang; Komossa, S.; Zensus, J. A.; Yuan, Weimin; Wajima, Kiyoaki; Zhou, Hongyan

    2015-11-15

    We present the detection of the compact radio structures of 14 radio-loud narrow-line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array (VLBA) observations at 5 GHz performed in 2013. While 50% of the sources of our sample show a compact core only, the remaining 50% exhibit a core-jet structure. The measured brightness temperatures of the cores range from 10{sup 8.4} to 10{sup 11.4} K with a median value of 10{sup 10.1} K, indicating that the radio emission is from non-thermal jets, and that, likely, most sources are not strongly beamed, thus implying a low jet speed in these radio-loud NLS1 galaxies. In combination with archival data taken at multiple frequencies, we find that seven sources show flat or even inverted radio spectra, while steep spectra are revealed in the remaining seven objects. Although all of these sources are very radio-loud with R > 100, their jet properties are diverse in terms of their milliarcsecond (mas) scale (parsec scale) morphology and their overall radio spectral shape. The evidence for slow jet speeds (i.e., less relativistic jets), in combination with the low kinetic/radio power, may offer an explanation for the compact VLBA radio structure in most sources. The mildly relativistic jets in these high accretion rate systems are consistent with a scenario where jets are accelerated from the hot corona above the disk by the magnetic field and the radiation force of the accretion disk. Alternatively, a low jet bulk velocity can be explained by low spin in the Blandford–Znajek mechanism.

  13. 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.

  14. 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.

  15. The UV to hard X-ray continuum of a Seyfert galaxy scrutinized by XMM and NuSTAR

    NASA Astrophysics Data System (ADS)

    Petrucci, Pierre-Olivier

    2013-10-01

    We propose to perform a unique XMM-NuSTAR monitoring with 5 repeated observations of 20 ks spaced by a few days of the Seyfert galaxy NGC 4593. This is the best Seyfert candidate to obtain high sensitivity measurements on a day time scale over the entire high energy spectrum. This is an absolute prerequisite 1) to correctly disentangle the different spectral components present in this energy band, and 2) to reveal their complex interdependences and variability behavior. This study will allow us i) to constrain the physical parameters of the Comptonizing corona; ii) to investigate the nature of the soft X-ray excess; iii) to put firm conclusions on the distance, nature and geometry of the reflecting material(s).

  16. Broad iron emission lines in Seyfert galaxies - re-condensation of gas onto an inner disk below the ADAF?

    NASA Astrophysics Data System (ADS)

    Meyer-Hofmeister, E.; Meyer, F.

    2011-03-01

    Context. The number of strong iron Kα line detections in Seyfert AGN is clearly growing in the Chandra, XMM-Newton and Suzaku era. The iron emission lines are broad, some are relativistically blurred. These relativistic disk lines have also been observed for galactic black hole X-ray binaries. Thermal components found in hard spectra were interpreted as an indication for a weak inner cool accretion disk underneath a hot corona. Aims: Accretion in low-mass X-ray binaries (LMXB) occurs during phases of high and low mass accretion rate, outburst and quiescence, soft and hard spectral state, respectively. After the soft/hard transition for some sources a thermal component is found, which can be interpreted as sustained by re-condensation of gas from an advection-dominated flow (ADAF) onto the disk. In view of the similarity of accretion flows around stellar mass and supermassive black holes we discuss whether the broad iron emission lines in Seyfert 1 AGN (active galactic nuclei) can be understood as arising from a similar accretion flow geometry as in X-ray binaries. Methods: We derive accretion rates for those Seyfert galaxies for which broad iron emission lines were observed, the "best candidates" in the investigations of Miller (2007, ARA&A, 45, 441) and Nandra et al. (2007, MNRAS, 382, 194). For the evaluation of the Eddington-scaled rates we use the observed X-ray luminosity, bolometric corrections and black hole masses from the literature. Results: The accretion rates derived for the Seyfert galaxies in our sample are less than 0.1 of the Eddington rate for more than half of the sources. For 107 to 108M⊙ black holes in Seyfert 1 AGN this limit corresponds to 0.01 to 0.2 M⊙/yr. This documents that the sources probably are in a hard spectral state and iron emission lines can arise from an inner weak accretion disk surrounded by an ADAF as predicted by the re-condensation model. Some of the remaining sources with higher accretion rates may be in a spectral

  17. A multi-wavelength survey of obscured and reddened quasars at the peak of galaxy formation

    NASA Astrophysics Data System (ADS)

    Alexandroff, Rachael

    2017-01-01

    While in the nearby universe the unification model seems firmly established, we are now seeing hints that at the peak of quasar activity and black hole growth (z~2.5) both obscured and reddened quasars may represent not just a specific quasar orientation but instead a unique stage of quasar evolution. Our group has developed several observational techniques to identify obscured and highly reddened quasars at z~2.5 using a combination of the SDSS spectroscopy and WISE photometry. Our sample contains objects with some of the most extreme ionized gas velocities observed (> 5000 km/s), indicating wind speeds too large to be contained by the galaxy potential though they are radio quiet. I will present both our sample selection and initial results from multi-wavelength follow-up of this sample using near-infrared spectroscopy, Keck spectropolarimentry and the VLA to test the AGN unification model and search for evidence of galaxy-wide quasar winds. High levels of polarized light (reaching ~20% of the total continuum emission in some cases) and changes in the polarization fraction and position angle across emission lines may argue for the presence of dusty outflows in our objects. This is supported by evidence from stacking analysis in the radio that presents a correlation between the observed outflow speeds in ionized gas (as measured by [OIII]) and the radio luminosity—arguing for a wind origin for the radio emission in these objects as well. The most extreme of these objects may thus represent the “blowout phase” of AGN evolution that proceeds or accompanies the cessation of star formation in the host galaxy due to the effects of radiatively-driven quasar driven winds.

  18. 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.

  19. The Most Luminous Heavily Obscured Quasars Have a High Merger Fraction: Morphological Study of WISE-selected Hot Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Fan, Lulu; Han, Yunkun; Fang, Guanwen; Gao, Ying; Zhang, Dandan; Jiang, Xiaoming; Wu, Qiaoqian; Yang, Jun; Li, Zhao

    2016-05-01

    Previous studies have shown that Wide-field Infrared Survey Explorer-selected hyperluminous, hot dust-obscured galaxies (Hot DOGs) are powered by highly dust-obscured, possibly Compton-thick active galactic nuclei (AGNs). High obscuration provides us a good chance to study the host morphology of the most luminous AGNs directly. We analyze the host morphology of 18 Hot DOGs at z ˜ 3 using Hubble Space Telescope/WFC3 imaging. We find that Hot DOGs have a high merger fraction (62 ± 14%). By fitting the surface brightness profiles, we find that the distribution of Sérsic indices in our Hot DOG sample peaks around 2, which suggests that most Hot DOGs have transforming morphologies. We also derive the AGN bolometric luminosity (˜1014 L ⊙) of our Hot DOG sample by using IR spectral energy distributions decomposition. The derived merger fraction and AGN bolometric luminosity relation is well consistent with the variability-based model prediction. Both the high merger fraction in an IR-luminous AGN sample and relatively low merger fraction in a UV/optical-selected, unobscured AGN sample can be expected in the merger-driven evolutionary model. Finally, we conclude that Hot DOGs are merger-driven and may represent a transit phase during the evolution of massive galaxies, transforming from the dusty starburst-dominated phase to the unobscured QSO phase.

  20. The fast molecular outflow in the Seyfert galaxy IC 5063 as seen by ALMA

    NASA Astrophysics Data System (ADS)

    Morganti, Raffaella; Oosterloo, Tom; Oonk, J. B. Raymond; Frieswijk, Wilfred; Tadhunter, Clive

    2015-08-01

    We use high-resolution (0.5 arcsec) CO(2-1) observations performed with the Atacama Large Millimetre/submillimetre Array to trace the kinematics of the molecular gas in the Seyfert 2 galaxy IC 5063. 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 western lobe. The ALMA data show that a massive, fast outflow with velocities up to 650kms-1 of cold molecular gas is present, in addition to the outflow detected earlier in warm H2, H i and ionized gas. All phases of the gas outflow show similar kinematics. IC 5063 appears to be one of the best examples of the multi-phase nature of AGN-driven outflows. Both the central AGN and the radio jet could energetically drive the outflow, however, the characteristics of the outflowing gas point to the radio jet being the main driver. This is an important result because IC 5063, although one of the most powerful Seyfert galaxies, is a relatively weak radio source (P1.4 GHz = 3 × 1023 W Hz-1). 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 model is consistent with results obtained by recent simulations. A stronger, direct interaction between the jet and a gas cloud is present at the location of the brighter western lobe. This interaction may also be responsible for the asymmetry in the radio brightness of the two lobes. Even assuming the most conservative values for the conversion factor CO-to-H2, we find that the mass of the outflowing gas is between 1.9 and 4.8 × 107 M⊙, of which between 0.5 and 1.3 × 107 M⊙ is associated with the fast outflow at the location of the western lobe. These amounts are much larger than those of the

  1. STAR FORMATION AND DUST OBSCURATION IN THE TIDALLY DISTORTED GALAXY NGC 2442

    SciTech Connect

    Pancoast, Anna; Sajina, Anna; Lacy, Mark; Noriega-Crespo, Alberto; Rho, Jeonghee

    2010-11-01

    We present a detailed investigation of the morphological distribution and level of star formation and dust obscuration in the nearby tidally distorted galaxy NGC 2442. Spitzer images in the IR at 3.6, 4.5, 5.8, 8.0, and 24 {mu}m and GALEX images at 1500 A and 2300 A allow us to resolve the galaxy on scales between {approx}240 and 600 pc. We supplement these with archival data in the B, J, H, and K bands. We use the 8 {mu}m, 24 {mu}m, and FUV (1500 A) emission to study the star formation rate (SFR). We find that, globally, these tracers of star formation give a range of results of {approx}6-11 M{sub sun} yr{sup -1}, with the dust-corrected FUV giving the highest value of SFR. We can reconcile the UV- and IR-based estimates by adopting a steeper UV extinction curve that lies in between the starburst (Calzetti) and Small Magellanic Cloud extinction curves. However, the regions of the highest SFR intensity along the spiral arms are consistent with a starburst-like extinction. Overall, the level of star formation we find is higher than previously published for this galaxy, by about a factor of 2, which, contrary to previous conclusions, implies that the interaction that caused the distorted morphology of NGC 2442 likely also triggered increased levels of star formation activity. We also find marked asymmetry in that the north spiral arm has a noticeably higher SFR than the southern arm. The tip of the southern spiral arm shows a likely tidally distorted peculiar morphology. It is UV bright and shows unusual IRAC colors, consistent with other published tidal features IRAC data. Outside of the spiral arms, we discover what appears to be a superbubble, {approx}1.7 kpc across, which is seen most clearly in the IRAC images. Significant H{alpha}, UV, and IR emission in the area also suggest vigorous ongoing star formation. A known, recent supernova (SN 1999ga) is located at the edge of this superbubble. Although speculative at this stage, this area suggests a large star

  2. VARIABLE REDDENING AND BROAD ABSORPTION LINES IN THE NARROW-LINE SEYFERT 1 GALAXY WPVS 007: AN ORIGIN IN THE TORUS

    SciTech Connect

    Leighly, Karen M.; Cooper, Erin; Grupe, Dirk; Terndrup, Donald M.; Komossa, S.

    2015-08-10

    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.

  3. EVIDENCE FOR A WIDE RANGE OF ULTRAVIOLET OBSCURATION IN z {approx} 2 DUSTY GALAXIES FROM THE GOODS-HERSCHEL SURVEY

    SciTech Connect

    Penner, Kyle; Dickinson, Mark; Dey, Arjun; Kartaltepe, Jeyhan; Pope, Alexandra; Magnelli, Benjamin; Pannella, Maurilio; Aussel, Herve; Daddi, Emanuele; Elbaz, David; Buat, Veronique; Bussmann, Shane; Hwang, Ho Seong; Charmandaris, Vassilis; Dannerbauer, Helmut; Lin Lihwai; Magdis, Georgios; Morrison, Glenn; and others

    2012-11-01

    Dusty galaxies at z {approx} 2 span a wide range of relative brightness between rest-frame mid-infrared (8 {mu}m) and ultraviolet wavelengths. We attempt to determine the physical mechanism responsible for this diversity. Dust-obscured galaxies (DOGs), which have rest-frame mid-IR to UV flux density ratios {approx}> 1000, might be abnormally bright in the mid-IR, perhaps due to prominent emission from active galactic nuclei and/or polycyclic aromatic hydrocarbons, or abnormally faint in the UV. We use far-infrared data from the GOODS-Herschel survey to show that most DOGs with 10{sup 12} L {sub Sun} {approx}< L {sub IR} {approx}< 10{sup 13} L {sub Sun} are not abnormally bright in the mid-IR when compared to other dusty galaxies with similar IR (8-1000 {mu}m) luminosities. We observe a relation between the median IR to UV luminosity ratios and the median UV continuum power-law indices for these galaxies, and we find that only 24% have specific star formation rates that indicate the dominance of compact star-forming regions. This circumstantial evidence supports the idea that the UV- and IR-emitting regions in these galaxies are spatially coincident, which implies a connection between the abnormal UV faintness of DOGs and dust obscuration. We conclude that the range in rest-frame mid-IR to UV flux density ratios spanned by dusty galaxies at z {approx} 2 is due to differing amounts of UV obscuration. Of galaxies with these IR luminosities, DOGs are the most obscured. We attribute differences in UV obscuration to either (1) differences in the degree of alignment between the spatial distributions of dust and massive stars or (2) differences in the total dust content.

  4. 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.

  5. AGN - Dust-Obscured Galaxies at z~1-3 revealed by near-to-far infrared SED-fitting

    NASA Astrophysics Data System (ADS)

    Riguccini, Laurie

    Dust-Obscured galaxies (DOGs, Dey et al. 2008) are bright 24μm-selected sources with extreme obscuration at optical wavelengths (F24μ m /F R > 982). Recent studies (Dey et al. 2008, Bussmann et al. 2009) describe an evolutionary scenario in which the starbursting nature of submillimeter galaxies (SMGs) evolves into the composite nature of DOGs as an underlying AGN grows; this is followed by a quasar phase that terminates star formation (SF), leading to the formation of a passive, massive elliptical galaxy. Within this context, DOGs could provide a key insight to an extremely dusty stage in the evolution of galaxies at z ~ 2, where both AGN and SF activity coexist.

  6. NO EVIDENCE OF OBSCURED, ACCRETING BLACK HOLES IN MOST z = 6 STAR-FORMING GALAXIES

    SciTech Connect

    Willott, Chris J.

    2011-11-20

    It has been claimed that there is a large population of obscured, accreting black holes at high redshift and that the integrated black hole density at z = 6 as inferred from X-ray observations is {approx}100 times greater than that inferred from optical quasars. I have performed a stacking analysis of very deep Chandra X-ray data at the positions of photometrically selected z = 6 galaxy candidates. It is found that there is no evidence for a stacked X-ray signal in either the soft (0.5-2 keV) or hard (2-8 keV) X-ray bands. Previous work which reported a significant signal is affected by an incorrect method of background subtraction which underestimates the true background within the target aperture. The puzzle remains as to why the z = 6 black hole mass function has such a flat slope and a low normalization compared to the stellar mass function.

  7. A Multi-Band Photometric Study of Tidal Debris in a Compact Group of Galaxies: Seyfert's Sextet

    NASA Astrophysics Data System (ADS)

    Nishiura, Shingo; Shioya, Yasuhiro; Murayama, Takashi; Sato, Yasunori; Nagao, Tohru; Taniguchi, Yoshiaki; Sanders, David B.

    2002-02-01

    In order to investigate the properties of the prominent tidal debris feature extending to the northeast of a compact group of galaxies, Seyfert's Sextet, we analyzed multi-band (U, B, V, VR, R, I, J, H, and K') photometric imaging data and obtained the following results: 1) The radial surface brightness distribution of this tidal debris in Seyfert's Sextet (TDSS) in each band appears to be well approximated by an exponential profile. 2) The observed B-V color of TDSS is similar to those of dwarf elliptical galaxies in nearby clusters. 3) Comparing the spectral energy distribution (SED) of TDSS with theoretical photometric evolution models and with the SED of the stars in the outer part of HCG 79b, we find that its SED is comparable to that of a ~10Gyr-old stellar population with solar metallicity, similar to the stellar population in the outer part of HCG 79b. This suggests that TDSS consists of stars that may have been liberated from HCG 79b by strong ga laxy interactions, not a pre-existing dwarf galaxy as previously thought.

  8. Evidence for a Circum-Nuclear and Ionised Absorber in the X-ray Obscured Broad Line Radio Galaxy 3C 445

    NASA Technical Reports Server (NTRS)

    Braito, V.; Reeves, J. N.; Sambruna, R. M.; Gofford, J.

    2012-01-01

    Here we present the results of a Suzaku observation of the Broad Line Radio Galaxy 3C 445. We confirm the results obtained with the previous X-ray observations which unveiled the presence of several soft X-ray emission lines and an overall X-ray emission which strongly resembles a typical Seyfert 2 despite of the optical classification as an unobscured AGN. The broad band spectrum allowed us to measure for the first time the amount of reflection (R approximately 0.9) which together with the relatively strong neutral Fe Ka emission line (EW approximately 100 eV) strongly supports a scenario where a Compton-thick mirror is present. The primary X ray continuum is strongly obscured by an absorber with a column density of NH = 2 - 3 x 10(exp 23) per square centimeter. Two possible scenarios are proposed for the absorber: a neutral partial covering or a mildly ionised absorber with an ionisation parameter log xi approximately 1.0 erg centimeter per second. A comparison with the past and more recent X-ray observations of 3C 445 performed with XMM-Newton and Chandra is presented, which provided tentative evidence that the ionised and outflowing absorber varied. We argue that the absorber is probably associated with an equatorial diskwind located within the parsec scale molecular torus.

  9. Search for Hyperluminous Infrared Dust-obscured Galaxies Selected with WISE and SDSS

    NASA Astrophysics Data System (ADS)

    Toba, Y.; Nagao, T.

    2016-03-01

    We aim to search for hyperluminous infrared (IR) galaxies (HyLIRGs) with IR luminosity {L}{{IR}} > 1013 L⊙ by applying the selection method of dust-obscured galaxies (DOGs). They are spatially rare but could correspond to a maximum phase of cosmic star formation (SF) and/or active galactic nucleus (AGN) activity hence, they are a crucial population for understanding the SF and mass assembly history of galaxies. Combining the optical and IR catalogs obtained from the Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE), we performed the extensive HyLIRGs survey; we selected 5311 IR-bright DOGs with i - [22] > 7.0 and flux at 22 μm > 3.8 mJy in 14,555 deg2, where i and [22] are i-band and 22 μm AB magnitudes, respectively. Among them, 67 DOGs have reliable spectroscopic redshifts that enable us to estimate their total IR luminosity based on the spectral energy distribution fitting. Consequently, we successfully discovered 24 HyLIRGs among the 67 spectroscopically confirmed DOGs. We found that (i) i - [22] color of IR-bright DOGs correlates with the total IR luminosity and (ii) the surface number density of HyLIRGs is >0.17 deg-2. A large fraction (˜73%) of IR-bright DOGs with i - [22] > 7.5 show {L}{{IR}} > 1013 L⊙, and the DOG criterion we adopted could be independently effective against the “W1W2-dropout method,” based on four WISE bands, for searching hyperluminous IR populations of galaxies.

  10. X-Ray Warm Absorption and Emission in the Polar-scattered Seyfert 1 Galaxy Mrk 704

    NASA Astrophysics Data System (ADS)

    Laha, Sibasish; Dewangan, Gulab C.; Kembhavi, Ajit K.

    2011-06-01

    We present a detailed study of the ionized environment of the Seyfert 1 galaxy Mrk 704 using medium- and high-resolution X-ray spectra obtained with a long XMM-Newton observation. The 0.3-10 keV continuum, well described by a power law (Γ ≈ 1.86) and two blackbodies (kT ≈ 0.085 and 0.22 keV), is found to be affected by a neutral partial covering absorption (N H ≈ 1023 cm-2, covering fraction ≈0.22) and two warm absorber components. We identify a low-ionization, ξ ~ 20 erg cm s-1, and high outflow velocity, v ~ 1350 km s-1, phase producing the O VI and Fe M-shell unresolved-transition array. An additional high-ionization warm absorbing phase with ξ ~ 500 erg cm s-1 and low outflow velocity, v ~ 540 km s-1, gives rise to absorption features due to O VII, O VIII, N VI, N VII, and C VI. We also detected weak emission lines of He-like triplets from O VII and N VI ions, thus making Mrk 704 a Seyfert 1 galaxy with both warm absorption and emission. The emission lines are well described by two warm emitting, photoionized media with different densities but comparable ξ, suggesting discrete clouds of warm emission. The high-density phase (ne ~ 1013 cm-3) responsible for the resonance lines appears to outflow at high velocity ~5000 km s-1. The low-velocity, low-density phase is likely similar to the X-ray line emitting regions found in Seyfert 2 galaxies. The physical conditions of warm emitters and warm absorbers suggest that these clouds are similar but observed in absorption along our line of sight and in emission at other lines of sight. The unique line of sight passing close to the torus opening angle is likely responsible for the neutral partial covering absorption and our view of emission lines due to the suppressed continuum in this polar-scattered Seyfert 1 galaxy.

  11. Does the inner broad-line region dim down when the power turns up?. [Seyfert 1 galaxy NGC 5548

    NASA Technical Reports Server (NTRS)

    Sparke, Linda S.

    1993-01-01

    The temporal correlations of continuum and broad emission-line fluxes from the Seyfert galaxy NGC 5548 as measured during the 1989 monitoring campaign show two related peculiarities: first, some of the crosscorrelations of line and continuum flux appear steeper on the negative time lag side than the continuum autocorrelation itself; then, the autocorrelation of the line flux is sometimes more sharply peaked than the continuum autocorrelation function. These are here interpreted as evidence that conditions in the inner part of the broad-line region are such that some emission lines decrease in intensity as the continuum strengthens.

  12. On the deep minimum state in the Seyfert galaxy MCG-6-30-15

    NASA Astrophysics Data System (ADS)

    Reynolds, Christopher S.; Wilms, Jörn; Begelman, Mitchell C.; Staubert, Rüdiger; Kendziorra, Eckhard

    2004-04-01

    We present a detailed spectral analysis of the first observation of the Seyfert 1 galaxy MCG-6-30-15 by the European Photon Imaging Camera on board the XMM-Newton observatory, together with contemporaneous data from the Proportional Counter Array on the Rossi X-ray Timing Explorer. Confirming our previously published result, we find that the presence of extremely broadened reflection features from an ionized relativistic accretion disc is required even when one employs the latest X-ray reflection models and includes the effect of complex absorption. The extremely broadened reflection features are also present if the primary continuum is modelled with a thermal Comptonization spectrum rather than a simple power-law continuum. With this fact established, we examine these data using a relativistic smearing function corresponding to a `generalized thin accretion disc' model. We find strong evidence for torquing of the central parts of the accretion disc (presumably through magnetic interactions with the plunging region of the disc and/or the rotating black hole itself). Indeed, within the context of these torqued disc models, this system appears to be in a torque-dominated (or `infinite-efficiency') state at the time of this observation. In addition, we find marginal evidence that the X-ray emitting corona radiates a greater fraction of the total dissipated energy in the inner portions of the disc. We also perform a study of spectral variability within our observation. We find that the disc reflection features maintain roughly a constant equivalent width with respect to the observed continuum, as predicted by simple reflection models. Taken together with other studies of MCG-6-30-15 that find disc features to possess constant intensity at higher flux states, we suggest that the flux of disc features undergoes a saturation once the source emerges from a deep minimum state. We discuss the implications of these results for the physics of the deep minimum `state

  13. Spitzer Space Telescope Measurements of Dust Reverberation Lags in the Seyfert 1 Galaxy NGC 6418

    NASA Astrophysics Data System (ADS)

    Vazquez, Billy; Galianni, Pasquale; Richmond, Michael; Robinson, Andrew; Axon, David J.; Horne, Keith; Almeyda, Triana; Fausnaugh, Michael; Peterson, Bradley M.; Bottorff, Mark; Gallimore, Jack; Eltizur, Moshe; Netzer, Hagai; Storchi-Bergmann, Thaisa; Marconi, Alessandro; Capetti, Alessandro; Batcheldor, Dan; Buchanan, Catherine; Stirpe, Giovanna; Kishimoto, Makoto; Packham, Christopher; Perez, Enrique; Tadhunter, Clive; Upton, John; Estrada-Carpenter, Vicente

    2015-03-01

    We present results from a 15 month campaign of high-cadence (˜3 days) mid-infrared Spitzer and optical (B and V) monitoring of the Seyfert 1 galaxy NGC 6418, with the objective of determining the characteristic size of the dusty torus in this active galactic nucleus (AGN). We find that the 3.6 and 4.5 μm flux variations lag behind those of the optical continuum by 37.2-2.2+2.4 days and 47.1-3.1+3.1 days, respectively. We report a cross-correlation time lag between the 4.5 and 3.6 μm flux of 13.9-0.1+0.5 days. The lags indicate that the dust emitting at 3.6 and 4.5 μm is located at a distance ≈ 1 light-month (≈ 0.03 pc) from the source of the AGN UV-optical continuum. The reverberation radii are consistent with the inferred lower limit to the sublimation radius for pure graphite grains at 1800 K, but smaller by a factor of ˜2 than the corresponding lower limit for silicate grains; this is similar to what has been found for near-infrared (K-band) lags in other AGNs. The 3.6 and 4.5 μm reverberation radii fall above the K-band τ \\propto {{L}0.5} size-luminosity relationship by factors ≲ 2.7 and ≲ 3.4, respectively, while the 4.5 μm reverberation radius is only 27% larger than the 3.6 μm radius. This is broadly consistent with clumpy torus models, in which individual optically thick clouds emit strongly over a broad wavelength range.

  14. A massive dense gas cloud close to the nucleus of the Seyfert galaxy NGC 1068

    NASA Astrophysics Data System (ADS)

    Furuya, Ray S.; Taniguchi, Yoshiaki

    2016-12-01

    Using the ALMA archival data of both 12CO (6-5) line and 689-GHz continuum emission towards the archetypical Seyfert galaxy, NGC 1068, we identified a distinct continuum peak separated by 15 pc from the nuclear radio component S1 in projection. The continuum flux gives a gas mass of ˜2 × 105 M⊙ and bolometric luminosity of ˜108 L⊙, leading to a star formation rate of ˜0.1 M⊙ yr-1. Subsequent analysis on the line data suggest that the gas cloud has a size of ˜10 pc, yielding to a mean H2 number density of ˜105 cm-3. We therefore refer to the gas as a "massive dense gas cloud": the gas density is high enough to form a "protostar cluster" with a stellar mass of ˜104 M⊙. We found that the gas stands at a unique position between galactic and extraglactic clouds in the diagrams of start formation rate (SFR) vs. gas mass proposed by Lada et al. (2012, ApJ, 745, 190) and surface density of gas vs. SFR density by Krumholz and McKee (2005, ApJ, 630, 250). All the gaseous and star-formation properties may be understood in terms of the turbulence-regulated star formation scenario. Since there are two stellar populations with ages of 300 Myr and 30 Myr in the 100 pc scale circumnulear region, we discuss that NGC 1068 has experienced at least three episodic star-formation events with the likelihood that the inner star-forming region is the younger. Together with several lines of evidence that the dynamics of the nuclear region is decoupled from that of the entire galactic disk, we discuss that the gas inflow towards the nuclear region of NGC 1068 may be driven by a past minor merger.

  15. 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.

  16. 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.

  17. Gas inflows towards the nucleus of the Seyfert 2 galaxy NGC 1667

    NASA Astrophysics Data System (ADS)

    Schnorr-Müller, Allan; Storchi-Bergmann, Thaisa; Ferrari, Fabricio; Nagar, Neil M.

    2017-01-01

    We use optical spectra from the inner 2 × 3 kpc2 of the Seyfert 2 galaxy NGC 1667, obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈ 240 pc, to assess the feeding and feedback processes in this nearby AGN. We have identified two gaseous kinematical components in the emission line profiles: a broader component (σ ≈ 400 km s-1) which is observed in the inner 1-2″ and a narrower component (σ ≈ 200 km s-1) which is present over the entire field-of-view. We identify the broader component as due to an unresolved nuclear outflow. The narrower component velocity field shows strong isovelocity twists relative to a rotation pattern, implying the presence of strong non-circular motions. The subtraction of a rotational model reveals that these twists are caused by outflowing gas in the inner ≈ 1″, and by inflows associated with two spiral arms at larger radii. We calculate an ionized gas mass outflow rate of dot{M}_{out} ≈ 0.16 M⊙ yr-1. We calculate the net gas mass flow rate across a series of concentric rings, obtaining a maximum mass inflow rate in ionized gas of ≈ 2.8 M⊙ year-1 at 800 pc from the nucleus, which is two orders of magnitude larger than the accretion rate necessary to power this AGN. However, as the mass inflow rate decreases at smaller radii, most of the gas probably will not reach the AGN, but accumulate in the inner few hundred parsecs. This will create a reservoir of gas that can trigger the formation of new stars.

  18. 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

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

    NASA Astrophysics Data System (ADS)

    Spinoglio, Luigi; Malkan, Matthew A.; Smith, Howard A.; González-Alfonso, Eduardo; Fischer, Jacqueline

    2005-04-01

    We report on the analysis of the first complete far-infrared spectrum (43-197 μm) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). In addition to the seven expected ionic fine-structure emission lines, the OH rotational lines at 79, 119, and 163 μm were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 μm line, when detected, is always in absorption. The observed line intensities were modeled together with ISOShort Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the active galactic nucleus (AGN) component and the starburst component in the circumnuclear ring of ~3 kpc 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 Brγ 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=10-3.5) and low densities (n=100 cm-3) are derived. Combining the AGN and starburst components, we succeeded in modeling the overall UV to far-IR atomic spectrum of NGC 1068, reproducing the line fluxes to within a factor of 2.0 on average with a standard deviation of 1.3, and the overall continuum as the sum of the contribution of the thermal dust emission in the ionized and neutral components. The OH 119 μm 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, nonlocal, non-LTE radiative transfer models. The models indicate that the bulk of the emission

  20. A Radio Study of the Seyfert Galaxy IC 5063: Evidence for Fast Gas Outflow

    NASA Astrophysics Data System (ADS)

    Morganti, R.; Oosterloo, T.; Tsvetanov, Z.

    1998-03-01

    We present new radio continuum (8 and 1.4 GHz) and H i 21 cm line observations of the Seyfert 2 galaxy IC 5063 (PKS 2048-572), obtained with the Australia Telescope Compact Array. The high-resolution 8 GHz image reveals a linear triple structure ~4" (1.3 kpc) in size. This small-scale radio emission shows a strong morphological association with the narrow-line region (NLR), the inner part of the optical emission-line region. It is aligned with the inner dust lane and is oriented perpendicularly to the position angle of the optical polarization. We identify the radio nucleus as the central blob of the radio emission. At 21 cm, very broad (~700 km s^-1) H i absorption is observed against the strong continuum source. This absorption is almost entirely blueshifted, indicating a fast net outflow, but a faint and narrow redshifted component is also present. In IC 5063 we see clear evidence, both morphological and kinematic, of strong shocks resulting from the interaction between the radio plasma and the interstellar medium (ISM) in the central few kiloparsecs. However, we estimate the energy flux in the radio plasma to be an order of magnitude smaller than the energy flux emitted in emission lines. Thus, although strong shocks associated with the jet/ISM interaction occur, and could contribute locally to the ionization of the NLR, they are unlikely to account solely for the global ionization of the emission-line region, particularly at large distances. The main structure of the H i emission is a warped disk associated with the system of dust lanes of R ~ 2' (~38 kpc, corresponding to ~5 effective radii). The lack of kinematically disturbed gas (both neutral and ionized) outside the central few kiloparsecs, the warped structure of the large-scale disk, and the close morphological connection between the inner dust lanes and the large-scale ionized gas all support the idea that the gas at large radii is photoionized by the central region, while shadowing effects are

  1. THE STAR FORMATION HISTORIES OF z {approx} 2 DUST-OBSCURED GALAXIES AND SUBMILLIMETER-SELECTED GALAXIES

    SciTech Connect

    Bussmann, R. S.; Dey, Arjun; Jannuzi, B. T.; Armus, L.; Desai, V.; Soifer, B. T.; Brown, M. J. I.; Gonzalez, A. H.; Melbourne, J.

    2012-01-10

    The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z {approx} 2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M{sub *}) of two populations of Spitzer-selected ULIRGs that have extremely red R - [24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6 {mu}m associated with stellar emission ({sup b}ump DOGs{sup )}, while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ({sup p}ower-law DOGs{sup )}. We measure M{sub *} by applying Charlot and Bruzual stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations. Assuming a simple stellar population and a Chabrier initial mass function, we find that power-law DOGs and bump DOGs are on average a factor of 2 and 1.5 more massive than SMGs, respectively (median and inter-quartile M{sub *} values for SMGs, bump DOGs, and power-law DOGs are log(M{sub *}/M{sub Sun }) = 10.42{sup +0.42}{sub -0.36}, 10.62{sup +0.36}{sub -0.32}, and 10.71{sup +0.40}{sub -0.34}, respectively). More realistic star formation histories drawn from two competing theories for the nature of ULIRGs at z {approx} 2 (major merger versus smooth accretion) can increase these mass estimates by up to 0.5 dex. A comparison of our stellar masses with the instantaneous star formation rate (SFR) in these z {approx} 2 ULIRGs provides a preliminary indication supporting high SFRs for a given M{sub *}, a situation that arises more naturally in major mergers than in smooth accretion-powered systems.

  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. INFRARED LUMINOSITIES AND DUST PROPERTIES OF z approx 2 DUST-OBSCURED GALAXIES

    SciTech Connect

    Bussmann, R. S.; Dey, Arjun; Jannuzi, B. T.; Borys, C.; Desai, V.; Sheth, K.; Soifer, B. T.; Le Floc'h, E.; Melbourne, J.

    2009-11-01

    We present SHARC-II 350 mum imaging of twelve 24 mum bright (F{sub 24m}u{sub m} > 0.8 mJy) Dust-Obscured Galaxies (DOGs) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) 1 mm imaging of a subset of two DOGs. These objects are selected from the Booetes field of the NOAO Deep Wide-Field Survey. Detections of four DOGs at 350 mum imply infrared (IR) luminosities which are consistent to within a factor of 2 of expectations based on a warm-dust spectral energy distribution (SED) scaled to the observed 24 mum flux density. The 350 mum upper limits for the 8 non-detected DOGs are consistent with both Mrk 231 and M82 (warm-dust SEDs), but exclude cold dust (Arp 220) SEDs. The two DOGs targeted at 1 mm were not detected in our CARMA observations, placing strong constraints on the dust temperature: T{sub dust} > 35-60 K. Assuming these dust properties apply to the entire sample, we find dust masses of approx3 x 10{sup 8} M{sub sun}. In comparison to other dusty z approx 2 galaxy populations such as submillimeter galaxies (SMGs) and other Spitzer-selected high-redshift sources, this sample of DOGs has higher IR luminosities (2 x 10{sup 13} L{sub sun} versus 6 x 10{sup 12} L{sub sun} for the other galaxy populations) that are driven by warmer dust temperatures (>35-60 K versus approx30 K) and lower inferred dust masses (3 x 10{sup 8} M{sub sun} versus 3 x 10{sup 9} M{sub sun}). Wide-field Herschel and Submillimeter Common-User Bolometer Array-2 surveys should be able to detect hundreds of these power-law-dominated DOGs. We use the existing Hubble Space Telescope and Spitzer/InfraRed Array Camera data to estimate stellar masses of these sources and find that the stellar to gas mass ratio may be higher in our 24 mum bright sample of DOGs than in SMGs and other Spitzer-selected sources. Although much larger sample sizes are needed to provide a definitive conclusion, the data are consistent with an evolutionary trend in which the formation of massive galaxies

  4. VizieR Online Data Catalog: Narrow line Seyfert 1 galaxies from SDSS-DR3 (Zhou+, 2006)

    NASA Astrophysics Data System (ADS)

    Zhou, H.; Wang, T.; Yuan, W.; Lu, H.; Dong, X.; Wang, J.; Lu, Y.

    2017-01-01

    We carried out a systematic search for narrow line Seyfert 1 galaxies (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. (1 data file).

  5. ON THE NUCLEAR OBSCURATION OF H{sub 2}O MASER GALAXIES

    SciTech Connect

    Zhang, J. S.; Guo, Q.; Wang, H. G.; Fan, J. H.; Henkel, C.

    2010-01-10

    To shed light onto the circumnuclear environment of 22 GHz ({lambda} {approx} 1.3 cm) H{sub 2}O maser galaxies, we have analyzed some of their multiwavelength properties, including the far-infrared luminosity (FIR), the luminosity of the [O{sub III}]{lambda}5007 emission line, the nuclear X-ray luminosity, and the equivalent width (EW) of the neutral iron K{alpha} emission line (EW (K{sub {alpha}})). Our statistical analysis includes a total of 85 sources, most of them harboring an active galactic nucleus (AGN). There are strong anticorrelations between EW (K{sub {alpha}}) and two 'optical thickness parameters', i.e., the ratios of the X-ray luminosity versus the presumably more isotropically radiated [O{sub III}] and FIR luminosities. Based on these anticorrelations, a set of quantitative criteria, EW (K{sub {alpha}})>300 eV, L{sub 2-10keV}<2L{sub [O{sub III}]}, and L{sub FIR}>600 L{sub 2-10{sub keV}} can be established for Compton-thick nuclear regions. Eighteen H{sub 2}O maser galaxies belong to this category. There are no obvious correlations between the EW (K{sub a}lpha), the [O{sub III}] luminosity, and the isotropic H{sub 2}O maser luminosity. When comparing samples of Seyfert 2s with and without detected H{sub 2}O maser lines, there seem to exist differences in EW (K{sub {alpha}}) and the fraction of Compton-thick nuclei. This should be studied further. For AGN masers alone, there is no obvious correlation between FIR and H{sub 2}O maser luminosities. However, including masers associated with star-forming regions, a linear correlation is revealed. Overall, the extragalactic FIR-H{sub 2}O data agree with the corresponding relation for Galactic maser sources, extrapolated by several orders of magnitude to higher luminosities.

  6. X-ray observations of the Compton-thick Seyfert 2 galaxy, NGC 5643

    NASA Astrophysics Data System (ADS)

    Matt, G.; Bianchi, S.; Marinucci, A.; Guainazzi, M.; Iwawasa, K.; Jimenez Bailon, E.

    2013-08-01

    We present results from a ~55 ks long XMM-Newton observation of the obscured AGN, NGC 5643, performed in July 2009. A previous, shorter (about 10 ks) XMM-Newton observation in February 2003 had left two major issues open, the nature of the hard X-ray emission (Compton-thin vs. Compton-thick) and of the soft X-ray excess (photoionized vs. collisionally ionized matter). The new observation shows that the source is Compton-thick and that the dominant contribution to the soft X-ray emission is by photoionized matter (even if it is still unclear whether collisionally ionized matter may contribute as well). We also studied three bright X-ray sources that are in the field of NGC 5643. The ULX NGC 5643 X-1 was confirmed to be very luminous, even if more than a factor 2 fainter than in 2003. We then provided the first high-quality spectrum of the cluster of galaxies Abell 3602. The last source, CXOJ143244.5-442020, is likely an unobscured AGN, possibly belonging to Abell 3602.

  7. Near-Infrared Continuum and 3.3um PAH Imaging of the Starburst Ring in the Type I Seyfert Galaxy NGC 7469

    NASA Technical Reports Server (NTRS)

    Mazzarella, J.; Voit, G.; Soifer, B.; Matthews, K.; Graham, J.; Armus, L.; Shupe, D.

    1993-01-01

    High resolution near-infrared images of the type 1 Seyfert Galaxy NGC 7469 have been obtained to probe its dusty nuclear environment. Direct images are relatively featureless, but residual images created by subtacting a smooth model based on best-fitting elliptical isoophotes reveal a tight inner spiral whose high surface-brightness portions correspond to a previously detected 3.

  8. 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

  9. Infrared Spectral Energy Distribution Decomposition of WISE-selected, Hyperluminous Hot Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Fan, Lulu; Han, Yunkun; Nikutta, Robert; Drouart, Guillaume; Knudsen, Kirsten K.

    2016-06-01

    We utilize a Bayesian approach to fit the observed mid-IR-to-submillimeter/millimeter spectral energy distributions (SEDs) of 22 WISE-selected and submillimeter-detected, hyperluminous hot dust-obscured galaxies (Hot DOGs), with spectroscopic redshift ranging from 1.7 to 4.6. We compare the Bayesian evidence of a torus plusgraybody (Torus+GB) model with that of a torus-only (Torus) model and find that the Torus+GB model has higher Bayesian evidence for all 22 Hot DOGs than the torus-only model, which presents strong evidence in favor of the Torus+GB model. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are as follows. (1) Hot DOGs in our submillimeter-detected sample are hyperluminous ({L}{IR}≥slant {10}13{L}⊙ ), with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, contributing on average ˜ 24% of total IR luminosity. (2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submillimeter at rest frame, while it is very similar to that of QSOs at ˜ 10{--}50 μ {{m}}, suggesting that the heating sources of Hot DOGs should be buried AGNs. (3) Hot DOGs have high dust temperatures ({T}{dust}˜ 72 K) and high IR luminosity of cold dust. The {T}{dust}{--}{L}{IR} relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust temperature, rather than dust mass. Hot DOGs have lower dust masses than submillimeter galaxies (SMGs) and QSOs within a similar redshift range. Both high IR luminosity of cold dust and relatively low dust mass in Hot DOGs can be expected by their relatively high dust temperatures. (4) Hot DOGs have high dust-covering factors (CFs), which deviate from the previously proposed trend of the dust CF decreasing with increasing bolometric luminosity. Finally, we can reproduce the observed

  10. Joint ROSAT-Compton GRO observations of the X-ray bright Seyfert galaxy IC 4329A

    NASA Technical Reports Server (NTRS)

    Madejski, G. M.; Zdziarski, A. A.; Turner, T. J.; Done, C.; Mushotzky, R. F.; Hartman, R. C.; Gehrels, N.; Connors, A.; Fabian, A. C.; Nandra, K.

    1995-01-01

    We report a simultaneous ROSAT and Gamma Ray Observatory (GRO) observation of the X-ray-bright Seyfert galaxy IC 4329A. For the GRO Oriented Scintillation Spectrometer Experiment (OSSE) detector, we also present the sum of the data for this and earlier observations. The overall spectrum is very well described as a power law with an energy spectral index of approximately 1 absorbed at low energies plus a strong Compton reflection component, typical for Seyfert 1 galaxies. The low energy absorption can be well described by a sum of a neutral column density of approximately 3 x 10(exp 21)sq cm, most of which is associated with the edge-on galactic disk of IC 4329A, plus an edgelike feature at approximately 700 eV; this feature implies either complex absorption (due to additional ionized material, or due to a partial covering), or a soft excess. The data only weakly constrain the presence of a high-energy cutoff in the underlying power law; they are compatible with an exponential cutoff at any energy E(sub c) approximately greater than 100 keV. The relative steepness of the OSSE data, with the power-law energy index of 1.6 +/- 0.2, can be accounted for entirely by the contribution of the high-energy tail of the reflection component when E(sub c) approaches infinity. (We find that the definite cutoff at an energy E(sub c)approximately 130 keV suggested in the recently published analysis of the OSSE data for this subject is due to a data reduction error.) Including nonsimultaneous Ginga observations with 2 keV fluxes matching well that of ROSAT gives us likely broad-band X-ray/gamma-ray spectra of the object from approximately 0.1 keV up to several hundred keV. We also report the ROSAT spectrum of the companion object to the Seyfert galaxy, the elliptical galaxy IC 4329.

  11. The average X-ray/gamma-ray spectra of Seyfert galaxies from Ginga and OSSE and the origin of the cosmic X-ray background

    NASA Technical Reports Server (NTRS)

    Zdziarski, Andrzej A.; Johnson, W. Neil; Done, Chris; Smith, David; Mcnaron-Brown, Kellie

    1995-01-01

    We have obtained the first average 2-500 keV spectra of Seyfert galaxies, using the data from Ginga and Compton Gamma-Ray Observatory's (CGRO) Oriented Scintillation Spectrometer Experiment (OSSE). Our sample contains three classes of objects with markedly different spectra: radio-quiet Seyfert 1's and 2's, and radio-loud Seyfert 1's. The average radio-quiet Seyfert 1 spectrum is well-fitted by a power law continuum with the energy spectral index alpha approximately equals 0.9, a Compton reflection component corresponding to a approximately 2 pi covering solid angle, and ionized absorption. There is a high-energy cutoff in the incident power law continuum: the e-folding energy is E(sub c) approximately equals 0.6(sup +0.8 sub -0.3) MeV. The simplest model that describes this spectrum is Comptonization in a relativistic optically-thin thermal corona above the surface of an accretion disk. Radio-quiet Seyfert 2's show strong netural absorption, and there is an indication that their X-ray power laws are intrinsically harder. Finally, the radio-loud Seyfert spectrum has alpha approximately equals 0.7, moderate neutral absorption E(sub C) = 0.4(sup +0.7 sub -0.2) MeV, and no or little Compton reflection. This is incompatible with the radio-quiet Seyfert 1 spectrum, and probably indicating that the X-rays are beamed away from the accretion disk in these objects. The average spectra of Seyferts integrated over redshift with a power-law evolution can explain the hard X-ray spectrum of the cosmic background.

  12. 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

  13. Multiwavelength Study of Active Galaxies

    NASA Astrophysics Data System (ADS)

    Singh, Veeresh

    2010-08-01

    Seyfert galaxies are a subclass of active galaxies and are categorized as nearby, low luminosity, radio-quiet Active Galactic Nuclei (AGN) hosted in spiral or lenticular galaxies. Demographically, Seyfert galaxies may account for ~ 10% of the entire population of active galaxies in the nearby universe. Seyfert galaxies are classified mainly into two subclasses named as `type 1' and `type 2' Seyferts, based on the presence and absence of broad permitted emission lines in their optical spectra, respectively. Detection of broad permitted emission lines in some Seyfert type 2s observed in the polarized light laid the foundation of the Seyfert unification scheme, which hypothesizes that Seyfert type 1s and type 2s belong to the same parent population and appear different solely due to the differing orientations of the obscuring material having a torus-like geometry around the AGN (Antonucci and Miller 1985; Antonucci 1993). The primary objective of this thesis work is to examine the validity and limitations of the orientation and obscuration based Seyfert unification scheme using multiwavelength (mainly X-ray and radio) observations. The key issue in testing the Seyfert unification scheme has been acquiring a well defined rigorously selected Seyfert sample. I have argued that the Seyfert samples based on flux limited surveys at optical, IR, UV and X-ray are likely to be biased against obscured and faint sources. In order to test the predictions of Seyfert unification scheme I use a sample based on properties (i.e., cosmological redshift, [OIII] emission line luminosity, absolute bulge magnitude, absolute stellar magnitude of the host galaxy and the Hubble stage of the host galaxy) that are independent to the orientation of the obscuring torus, host galaxy and the AGN axis. Furthermore, two Seyfert subtypes of our sample have matched distributions in the orientation-independent properties and this ensures the intrinsic similarity between two Seyfert subtypes within the

  14. Jet Properties of GeV-Selected Radio-Loud Narrow-line Seyfert 1 Galaxies and Possible Connection to Their Disk and Corona

    NASA Astrophysics Data System (ADS)

    Zhang, Jin

    2015-08-01

    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 (Lcorona) to the accretion disk luminosity (Ld) 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 Lcorona. However, it is still unclear whether a system with a high Lcorona/Ld ratio prefers to power a jet.

  15. Jet Properties of GeV-selected Radio-loud Narrow-line Seyfert 1 Galaxies and Possible Connection to Their Disk and Corona

    NASA Astrophysics Data System (ADS)

    Sun, Xiao-Na; Zhang, Jin; Lin, Da-Bin; Xue, Zi-Wei; Liang, En-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 corona) to the accretion disk luminosity (L 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 corona. However, it is still unclear whether a system with a high L corona/L d ratio prefers to power a jet.

  16. 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.

  17. Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches

    NASA Astrophysics Data System (ADS)

    Boone, F.; Schaerer, D.; Pelló, R.; Lutz, D.; Weiss, A.; Egami, E.; Smail, I.; Rex, M.; Rawle, T.; Ivison, R.; Laporte, N.; Beelen, A.; Combes, F.; Blain, A. W.; Richard, J.; Kneib, J.-P.; Zamojski, M.; Dessauges-Zavadsky, M.; Altieri, B.; van der Werf, P.; Swinbank, M.; Pérez-González, P. G.; Clement, B.; Nordon, R.; Magnelli, B.; Menten, K. M.

    2011-10-01

    The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshift dusty galaxies because both kind of galaxies cannot be distinguished. The contamination rate could be as high as 50%. This work shows how the far-infrared (FIR) domain can help to recognize likely low-z interlopers in an optical/NIR search for high-z galaxies. We analyze the FIR SEDs of two galaxies that are proposed to be very high-redshift (z > 7) dropout candidates based on deep Hawk-I/VLT observations. The FIR SEDs are sampled with PACS/Herschel at 100 and 160 μm, with SPIRE/Herschel at 250, 350 and 500 μm and with LABOCA/APEX at 870 μm. We find that redshifts > 7 would imply extreme FIR SEDs (with dust temperatures >100 K and FIR luminosities >1013 L⊙). At z ~ 2, instead, the SEDs of both sources would be compatible with those of typical ultra luminous infrared galaxies or submillimeter galaxies. Considering all available data for these sources from visible to FIR we re-estimate the redshifts and find z ~ 1.6-2.5. Owing to the strong spectral breaks observed in these galaxies, standard templates from the literature fail to reproduce the visible-to-near-IR part of the SEDs even when additional extinction is included. These sources strongly resemble dust-obscured galaxies selected in Spitzer observations with extreme visible-to-FIR colors, and the galaxy GN10 at z = 4. Galaxies with similar SEDs could contaminate other high-redshift surveys.

  18. 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.

  19. HerMES: THE FAR-INFRARED EMISSION FROM DUST-OBSCURED GALAXIES

    SciTech Connect

    Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A.; Assef, R. J.; Bock, J.; Riechers, D.; Schulz, B.; Casey, C. M.; Conley, A.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Ibar, E.; Kartaltepe, J.; Magdis, G.; Rigopoulou, D.; Marchetti, L.; Pérez-Fournon, I.; Scott, Douglas; and others

    2013-09-20

    Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg{sup 2} of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24 μm and r {sup +} observations using a color cut of r {sup +} – [24] ≥ 7.5 (AB mag) and S{sub 24} ≥ 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (≥3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 10{sup 12} L{sub ☉} and (0.77 ± 0.08) × 10{sup 12} L{sub ☉}, and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S{sub 24} ≥ 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S{sub 24} ≥ 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2.

  20. 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.

  1. 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.

  2. A spectroscopic analysis of a sample of narrow-line Seyfert 1 galaxies selected from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Cracco, V.; Ciroi, S.; Berton, M.; Di Mille, F.; Foschini, L.; La Mura, G.; Rafanelli, P.

    2016-10-01

    We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public archive. We confirm that NLS1s are mostly characterized by Balmer lines with Lorentzian profiles, lower black hole masses and higher Eddington ratios than classic broad-line Seyfert 1 (BLS1s), but they also appear to be active galactic nuclei (AGNs) contiguous with BLS1s and sharing with them common properties. Strong Fe II emission does not seem to be a distinctive property of NLS1s, as low values of Fe II/Hβ are equally observed in these AGNs. Our data indicate that Fe II and Ca II kinematics are consistent with the one of Hβ. On the contrary, O I λ8446 seems to be systematically narrower and it is likely emitted by gas of the broad-line region more distant from the ionizing source and showing different physical properties. Finally, almost all NLS1s of our sample show radial motions of the narrow-line region highly ionized gas. The mechanism responsible for this effect is not yet clear, but there are hints that very fast outflows require high continuum luminosities (>1044 erg s-1) or high Eddington ratios (log (Lbol/LEdd) > -0.1).

  3. 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.

  4. Spitzer-IRS High-Resolution Spectroscopy of the 12 μm Seyfert Galaxies. II. Results for the Complete Data Set

    NASA Astrophysics Data System (ADS)

    Tommasin, Silvia; Spinoglio, Luigi; Malkan, Matthew A.; Fazio, Giovanni

    2010-02-01

    We present our Spitzer-Infrared Spectrometer (IRS) spectroscopic survey from 10 μm to 37 μm of the Seyfert galaxies of the 12 μm Galaxy Sample, collected in a high-resolution mode (R ~ 600). The new spectra of 61 galaxies, together with the data we already published, give us a total of 91 12 μm Seyfert galaxies observed, out of 112. We discuss the mid-IR emission lines and features of the Seyfert galaxies, using an improved active galactic nucleus (AGN) classification scheme: instead of adopting the usual classes of Seyfert 1's and Seyfert 2's, we use the spectropolarimetric data from the literature to divide the objects into categories "AGN 1" and "AGN 2," where AGN 1's include all broad-line objects, including the Seyfert 2's showing hidden broad lines in polarized light. The remaining category, AGN 2's, contains only Seyferts with no detectable broad lines in either direct or polarized spectroscopy. We present various mid-IR observables, such as ionization-sensitive and density-sensitive line ratios, the polycyclic aromatic hydrocarbon (PAH) 11.25 μm feature and the H2 S(1) rotational line equivalent widths (EWs), the (60-25 μm) spectral index, and the source extendedness at 19 μm, to characterize similarities and differences in the AGN populations, in terms of AGN dominance versus star formation dominance. We find that the mid-IR emission properties characterize all the AGN 1's objects as a single family, with strongly AGN-dominated spectra. In contrast, the AGN 2's can be divided into two groups, the first one with properties similar to the AGN 1's except without detected broad lines, and the second with properties similar to the non-Seyfert galaxies, such as LINERs or starburst galaxies. We computed a semianalytical model to estimate the AGN and the starburst contributions to the mid-IR galaxy emission at 19 μm. For 59 galaxies with appropriate data, we can separate the 19 μm emission into AGN and starburst components using the measured mid

  5. Investigation of the Activity of the Nucleus of Seyfert Galaxy NGC 7469 during the Observation Period from 1990 TO 2008

    NASA Astrophysics Data System (ADS)

    Ugolkova, L. S.; Artamonov, B. P.

    We combine many published photometrical observations of the Seyfert Galaxy (SG) NGC 7469 and also new results from Hubble Space Telescope which can be used for future research of some properties of the activity of the nuclear of the SG. A drift of the activity maximum from 1997 to 1998 is observed with an increased of the wave length similarly to some blazars in radio range. Analyzing the surface photometry according to data obtained both at the Maidanak observatory and HST data an intensity asymmetry at the SG central region image is observed at different periods. The existence of a second component might be supposed. The radius of the active region itself inside the SG kernel is 40-50 parsec.

  6. 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

  7. Heavily Obscured AGN: An Ideal Laboratory To Study The Early Co-Evolution of Galaxies And Black Holes

    NASA Astrophysics Data System (ADS)

    Circosta, Chiara; Vignali, C.; Gilli, R.; Feltre, A.; Vito, F.

    2016-10-01

    Obscured AGN are a crucial ingredient to understand the full growth history of super massive black holes and the coevolution with their host galaxies, since they constitute the bulk of the BH accretion. In the distant Universe, many of them are hosted by submillimeter galaxies (SMGs), characterized by a high production of stars and a very fast consumption of gas. Therefore, the analysis of this class of objects is fundamental to investigate the role of the ISM in the early coevolution of galaxies and black holesWe collected a sample of six obscured X-ray selected AGN at z>2.5 in the CDF-S, detected in the far-IR/submm bands. We performed a multiwavelength analysis in order to characterize their physical properties, as well as those of their host galaxies (e.g. column density, accretion luminosity, stellar mass, SFR, dust and gas mass). I will present the results of the X-ray spectral analysis of these sources based on the 7Ms Chandra data - the deepest X-ray observation ever carried out on any field - along with their broad-band spectral energy distributions (SEDs), built up using the public UV to far-IR photometry from the CANDELS and Herschel catalogs. By comparing the column density associated with the ISM (estimated measuring the size of the system) with that obtained from the X-ray data, it is possible to understand whether the ISM in the host galaxy may be able to produce a substantial part of the observed nuclear obscuration.

  8. Interferometric follow-up of WISE hyper-luminous hot, dust-obscured galaxies

    SciTech Connect

    Wu, Jingwen; Wright, Edward L.; Bussmann, R. Shane; Tsai, Chao-Wei; Eisenhardt, Peter R. M.; Stern, Daniel; Moustakas, Leonidas; Petric, Andreea; Blain, Andrew; Bridge, Carrie R.; Benford, Dominic J.; Assef, Roberto J.; Gelino, Christopher R.

    2014-09-20

    The Wide-field Infrared Survey Explorer (WISE) has discovered an extraordinary population of hyper-luminous dusty galaxies that are faint in the two bluer passbands (3.4 μm and 4.6 μm) but are bright in the two redder passbands of WISE (12 μm and 22 μm). We report on initial follow-up observations of three of these hot, dust-obscured galaxies, or Hot DOGs, using the Combined Array for Research in Millimeter-wave Astronomy and the Submillimeter Array interferometer arrays at submillimeter/millimeter wavelengths. We report continuum detections at ∼1.3 mm of two sources (WISE J014946.17+235014.5 and WISE J223810.20+265319.7, hereafter W0149+2350 and W2238+2653, respectively), and upper limits to CO line emission at 3 mm in the observed frame for two sources (W0149+2350 and WISE J181417.29+341224.8, hereafter W1814+3412). The 1.3 mm continuum images have a resolution of 1''-2'' and are consistent with single point sources. We estimate the masses of cold dust are 2.0 × 10{sup 8} M {sub ☉} for W0149+2350 and 3.9 × 10{sup 8} M {sub ☉} for W2238+2653, comparable to cold dust masses of luminous quasars. We obtain 2σ upper limits to the molecular gas masses traced by CO, which are 3.3 × 10{sup 10} M {sub ☉} and 2.3 × 10{sup 10} M {sub ☉} for W0149+2350 and W1814+3412, respectively. We also present high-resolution, near-IR imaging with the WFC3 on the Hubble Space Telescope for W0149+2653 and with NIRC2 on Keck for W2238+2653. The near-IR images show morphological structure dominated by a single, centrally condensed source with effective radius less than 4 kpc. No signs of gravitational lensing are evident.

  9. Tracing the sites of obscured star formation in the Antennae galaxies with Herschel-PACS

    NASA Astrophysics Data System (ADS)

    Klaas, U.; Nielbock, M.; Haas, M.; Krause, O.; Schreiber, J.

    2010-07-01

    Aims: FIR imaging of interacting galaxies allows locating even hidden sites of star formation and measuring of the relative strength of nuclear and extra-nuclear star formation. We want to resolve the star-forming sites in the nearby system of the Antennae. Methods: Thanks to the unprecedented sharpness and depth of the PACS camera onboard ESA's Herschel Space Observatory, it is possible for the first time to achieve a complete assessment of individual star-forming knots in the FIR with scan maps at 70, 100, and 160 μm. We used clump extraction photometry and SED diagnostics to derive the properties related to star-forming activity. Results: The PACS 70, 100, and 160 μm maps trace the knotty structure of the most recent star formation along an arc between the two nuclei in the overlap area. The resolution of the starburst knots and additional multi-wavelength data allow their individual star formation history and state to be analysed. In particular, the brightest knot in the mid-infrared (K1), east of the southern nucleus, exhibits the highest activity by far in terms of dust heating and star formation rate, efficiency, and density. With only 2 kpc in diameter, this area has a 10-1000 μm luminosity, which is as high as that of our Milky Way. It shows the highest deficiency in radio emission in the radio-to-FIR luminosity ratio and a lack of X-ray emission, classifying it as a very young complex. The brightest 100 and 160 μm emission region (K2), which is close to the collision front and consists of 3 knots, also shows a high star formation density and efficiency and lack of X-ray emission in its most obscured part, but an excess in the radio-to-FIR luminosity ratio. This suggests a young stage, too, but different conditions in its interstellar medium. Our results provide important checkpoints for numerical simulations of interacting galaxies when modelling the star formation and stellar feedback. Herschel is an ESA space observatory with science instruments

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

    NASA Astrophysics Data System (ADS)

    Sharma, Neetika

    2016-08-01

    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.

  11. 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.

  12. NUSTAR Unveils a Heavily Obscured Low-luminosity Active Galactic Nucleus in the Luminous Infrared Galaxy NGC 6286

    NASA Astrophysics Data System (ADS)

    Ricci, C.; Bauer, F. E.; Treister, E.; Romero-Cañizales, C.; Arevalo, P.; Iwasawa, K.; Privon, G. C.; Sanders, D. B.; Schawinski, K.; Stern, D.; Imanishi, M.

    2016-03-01

    We report the detection of a heavily obscured active galactic nucleus (AGN) in the luminous infrared galaxy (LIRG) NGC 6286 identified in a 17.5 ks Nuclear Spectroscopic Telescope Array observation. The source is in an early merging stage and was targeted as part of our ongoing NuSTAR campaign observing local luminous and ultra-luminous infrared galaxies in different merger stages. NGC 6286 is clearly detected above 10 keV and by including the quasi-simultaneous Swift/XRT and archival XMM-Newton and Chandra data, we find that the source is heavily obscured (NH ≃(0.95-1.32) × 1024 cm-2) with a column density consistent with being Compton-thick (CT, {log}({N}{{H}}/{{cm}}-2)≥slant 24). The AGN in NGC 6286 has a low absorption-corrected luminosity (L2-10 keV ˜ 3-20 × 1041 erg s-1) and contributes ≲1% to the energetics of the system. Because of its low luminosity, previous observations carried out in the soft X-ray band (<10 keV) and in the infrared did not notice the presence of a buried AGN. NGC 6286 has multiwavelength characteristics typical of objects with the same infrared luminosity and in the same merger stage, which might imply that there is a significant population of obscured low-luminosity AGNs in LIRGs that can only be detected by sensitive hard X-ray observations.

  13. Gemini Near Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy Mrk 573: In Situ Acceleration of Ionized and Molecular Gas off Fueling Flows

    NASA Astrophysics Data System (ADS)

    Fischer, Travis C.; Machuca, C.; Diniz, M. R.; Crenshaw, D. M.; Kraemer, S. B.; Riffel, R. A.; Schmitt, H. R.; Baron, F.; Storchi-Bergmann, T.; Straughn, A. N.; Revalski, M.; Pope, C. L.

    2017-01-01

    We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in a ∼700 × 2100 pc2 circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out to several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. X-ray observations of dust obscured galaxies in the Chandra deep field south

    NASA Astrophysics Data System (ADS)

    Corral, A.; Georgantopoulos, I.; Comastri, A.; Ranalli, P.; Akylas, A.; Salvato, M.; Lanzuisi, G.; Vignali, C.; Koutoulidis, L.

    2016-08-01

    We present the properties of X-ray detected dust obscured galaxies (DOGs) in the Chandra deep field south. In recent years, it has been proposed that a significant percentage of the elusive Compton-thick (CT) active galactic nuclei (AGN) could be hidden among DOGs. This type of galaxy is characterized by a very high infrared (IR) to optical flux ratio (f24 μm/fR > 1000), which in the case of CT AGN could be due to the suppression of AGN emission by absorption and its subsequent re-emission in the IR. The most reliable way of confirming the CT nature of an AGN is by X-ray spectroscopy. In a previous work, we presented the properties of X-ray detected DOGs by making use of the deepest X-ray observations available at that time, the 2Ms observations of the Chandra deep fields, the Chandra deep field north (CDF-N), and the Chandra deep field south (CDF-S). In that work, we only found a moderate percentage (<50%) of CT AGN among the DOGs sample. However, we pointed out that the limited photon statistics for most of the sources in the sample did not allow us to strongly constrain this number. In this paper, we further explore the properties of the sample of DOGs in the CDF-S presented in that work by using not only a deeper 6Ms Chandra survey of the CDF-S, but also by combining these data with the 3Ms XMM-Newton survey of the CDF-S. We also take advantage of the great coverage of the CDF-S region from the UV to the far-IR to fit the spectral energy distributions (SEDs) of our sources. Out of the 14 AGN composing our sample, 9 are highly absorbed (NH > 1023 cm-2), whereas 2 look unabsorbed, and the other 3 are only moderately absorbed. Among the highly absorbed AGN, we find that only three could be considered CT AGN. In only one of these three cases, we detect a strong Fe Kα emission line; the source is already classified as a CT AGN with Chandra data in a previous work. Here we confirm its CT nature by combining Chandra and XMM-Newton data. For the other two CT

  1. PROBING THE PHYSICS OF NARROW LINE REGIONS IN ACTIVE GALAXIES. II. THE SIDING SPRING SOUTHERN SEYFERT SPECTROSCOPIC SNAPSHOT SURVEY (S7)

    SciTech Connect

    Dopita, Michael A.; Davies, Rebecca; Kewley, Lisa; Hampton, Elise; Sutherland, Ralph; Shastri, Prajval; Kharb, Preeti; Jose, Jessy; Bhatt, Harish; Ramya, S.; Scharwächter, Julia; Jin, Chichuan; Banfield, Julie; Zaw, Ingyin; Juneau, Stéphanie; Srivastava, Shweta

    2015-03-15

    Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph mounted on the ANU 2.3 m telescope located at the Siding Spring Observatory to deliver an integral field of 38 × 25 arcsec at a spectral resolution of R = 7000 in the red (530–710 nm), and R = 3000 in the blue (340–560 nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the Hβ and [O iii] λ5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the Hβ and [O iii] λ5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in [O iii] λ5007, [N ii] λ6584, and Hα, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding H ii regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines.

  2. Probing the Physics of Narrow Line Regions in Active Galaxies. II. The Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph mounted on the ANU 2.3 m telescope located at the Siding Spring Observatory to deliver an integral field of 38 × 25 arcsec at a spectral resolution of R = 7000 in the red (530-710 nm), and R = 3000 in the blue (340-560 nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the Hβ and [O iii] λ5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the Hβ and [O iii] λ5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in [O iii] λ5007, [N ii] λ6584, and Hα, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding H ii regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines.

  3. The obscured hyper-energetic GRB 120624B hosted by a luminous compact galaxy at z = 2.20

    NASA Astrophysics Data System (ADS)

    de Ugarte Postigo, A.; Campana, S.; Thöne, C. C.; D'Avanzo, P.; Sánchez-Ramírez, R.; Melandri, A.; Gorosabel, J.; Ghirlanda, G.; Veres, P.; Martín, S.; Petitpas, G.; Covino, S.; Fynbo, J. P. U.; Levan, A. J.

    2013-09-01

    Context. Gamma-ray bursts (GRBs) are the most luminous explosions that we can witness in the Universe. Studying the most extreme cases of these phenomena allows us to constrain the limits for the progenitor models. Aims: In this Letter, we study the prompt emission, afterglow, and host galaxy of GRB 120624B, one of the brightest GRBs detected by Fermi, to derive the energetics of the event and characterise the host galaxy in which it was produced. Methods: Following the high-energy detection we conducted a multi-wavelength follow-up campaign, including near-infrared imaging from HAWKI/VLT, optical from OSIRIS/GTC, X-ray observations from the Chandra X-ray Observatory and at submillimetre/millimetre wavelengths from SMA. Optical/NIR spectroscopy was performed with X-shooter/VLT. Results: We detect the X-ray and NIR afterglow of the burst and determine a redshift of z = 2.1974 ± 0.0002 through identification of emission lines of [O ii], [O iii] and H-α from the host galaxy of the GRB. This implies an energy release of Eiso,γ = (3.0 ± 0.2) × 1054 erg, amongst the most luminous ever detected. The observations of the afterglow indicate high obscuration with AV > 1.5. The host galaxy is compact, with R1/2 < 1.6 kpc, but luminous, at L ~ 1.5 L∗ and has a star formation rate of 91 ± 6 M⊙/yr as derived from Hα. Conclusions: As for other highly obscured GRBs, GRB 120624B is hosted by a luminous galaxy, which we also prove to be compact, with very intense star formation. It is one of the most luminous host galaxies associated with a GRB, showing that the host galaxies of long GRBs are not always blue dwarf galaxies, as previously thought. Based on observations collected at the European Southern Observatory, Chile, with programmes 089.D-0256 and 090.D-0667, at the Gran Telescopio Canarias with programmes GTC49-12A and GTC58-12B, at the Submillimeter Array with programme 2012A-S001, at CAHA with programme F13-3.5-031, at Liverpool Telescope with programme CL13A03

  4. 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.

  5. 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

  6. 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

  7. Narrow-line Seyfert Galaxies. Connection between abundance and the large-scale structure

    NASA Astrophysics Data System (ADS)

    Ermash, A. A.; Komberg, B. V.

    2014-12-01

    Utilizing methods, developed by the author the correlations between spatial concentrations of active nuclei (NLS and BLS) and concentration of galaxies of full uniform sample were obtained. Galaxies of this uniform sample trace the large-scale structure. We used SDSS DR 7 data. The correlations obtained are linear and the NLS/BLS ratio is constant. That leads to conclusion that amounts NLS and BLS are some fixed portion of all galaxies independent on the density of large-scale environment. In order to check validity of our results we also confirmed the well known result that fraction of red galaxies increases with density of environment. Also it was confirmed that this trend is more prominent for less massive galaxies.

  8. Molecular tori in Seyfert galaxies - Feeding the monster and hiding it

    NASA Technical Reports Server (NTRS)

    Krolik, Julian H.; Begelman, Mitchell C.

    1988-01-01

    The principal properties of the tori of gas which surround Seyfert nuclei are discussed. The internal state of the clouds and their size distribution function are examined, and it is shown that the Jeans mass scale results in clouds which are individually sufficiently opaque to block out the nucleus, and that the balance of processes which controls their size distribution function also forces the covering factor to be of the order of or greater than unity. Where the gravitational potential is dominated by stars, cloud-cloud collisions keep the molecular clouds close to the equatorial plane. Stirring by stellar processes is never strong enough to compete with collisional losses. The position of the inner edge of the torus is determined by a balance between the inward flow of clouds and the rate at which the nuclear continuum can evaporate them.

  9. The Large-Scale Galactic Outflow in the Seyfert Galaxy NGC 2992

    NASA Astrophysics Data System (ADS)

    Colbert, Edward

    2002-09-01

    Only now, with Chandra, can we finally image the hot gas in Large-Scale (kpc) Outflows (LSOs) in Seyferts and (a) study its X-ray morphology, (b) obtain reliable temperatures and luminosities, and (c) infer the density, mass, pressure and cooling time. These quantities can be compared with pressures, kinetic energy rates, and masses from models based on optical kinematic and radio data. The LSO in NGC 2992 is quite different from those that have already been observed with Chandra and have linear nuclear radio structures. It has a diffuse sub-kpc radio structure (but NO starburst) and a wide-angled outflow. We shall use the Chandra X-ray data with our optical Fabry-Perot data, radio images, and published ionization results to diagnose the LSO in NGC2992.

  10. VizieR Online Data Catalog: FeK lines in Seyfert 1 galaxies (Patrick+, 2012)

    NASA Astrophysics Data System (ADS)

    Patrick, A. R.; Reeves, J. N.; Porquet, D.; Markowitz, A. G.; Braito, V.; Lobban, A. P.

    2013-04-01

    The objects included within this sample are listed in Table 1 and are all the Seyfert 1-1.9 AGN with exposures >50ks and greater than 30000 0.6-10.0keV counts which have been observed with Suzaku with data publicly available in the Suzaku data archive (http://heasarc.gsfc.nasa.gov/) as of 2011 September. We also include data from some type 1 radio-loud (BLRGs - non-blazar) AGN, provided they fit the above exposure and count criteria. High-energy X-ray data from Swift-BAT from the 58-month BAT catalogue are also used in addition to that obtained from the HXD detector on-board Suzaku (but allowing the relative cross-normalization to vary), therefore the total energy range covered is 0.6-100.0keV. (4 data files).

  11. 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.

  12. The hidden quasar nucleus of a WISE-selected, hyperluminous, dust-obscured galaxy at z ~ 2.3

    NASA Astrophysics Data System (ADS)

    Piconcelli, E.; Vignali, C.; Bianchi, S.; Zappacosta, L.; Fritz, J.; Lanzuisi, G.; Miniutti, G.; Bongiorno, A.; Feruglio, C.; Fiore, F.; Maiolino, R.

    2015-02-01

    We present the first X-ray spectrum of a hot dust-obscured galaxy (DOG), namely W1835+4355 at z ~ 2.3. Hot DOGs represent a very rare population of hyperluminous (≥1047 erg s-1), dust-enshrouded objects at z ≥ 2 recently discovered in the WISE All Sky Survey. The 40 ks XMM-Newton spectrum reveals a continuum as flat (Γ ~ 0.8) as typically seen in heavily obscured AGN. This, along with the presence of strong Fe Kα emission, clearly suggests a reflection-dominated spectrum due to Compton-thick absorption. In this scenario, the observed luminosity of L2-10~ 2 × 1044 erg s-1 is a fraction (<10%) of the intrinsic one, which is estimated to be ≳ 5 × 1045 erg s-1 by using several proxies. The Herschel data allow us to constrain the SED up to the sub-mm band, providing a reliable estimate of the quasar contribution (~75%) to the IR luminosity as well as the amount of star formation (~2100 M⊙ yr-1). Our results thus provide additional pieces of evidence that associate Hot DOGs with an exceptionally dusty phase during which luminous quasars and massive galaxies co-evolve and a very efficient and powerful AGN-driven feedback mechanism is predicted by models.

  13. 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

  14. 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.

  15. Using Multiwavelength Observations to Determine the Black Hole Mass and Accretion Rate in the Type 1 Seyfert Galaxy NGC 5548

    NASA Technical Reports Server (NTRS)

    Chiang, James; Blaes, Omer

    2002-01-01

    We model the spectral energy distribution of the type 1 Seyfert galaxy NGC 5548, fitting data from simultaneous optical, UV, and X-ray monitoring observations. We assume a geometry consisting of a hot central Comptonizing region surrounded by a thin accretion disk. The properties of the disk and the hot central region are determined by the feedback occurring between the hot Comptonizing region and thermal reprocessing in the disk that, along with viscous dissipation, provides the seed photons for the Comptonization process. The constraints imposed upon this model by the multiwavelength data allow us to derive limits on the central black hole mass, Mu is approximately or less than 2x10(exp 7) solar mass, the accretion rate, Mu is approximately or less than 2.5x10(exp 5) sq solar mass per year/Mu, and the radius of the transition region between the thin outer disk and the geometrically thick, hot inner region, is approximately 2-5x10(exp 14) cm.

  16. 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.

  17. The Parsec-scale Structure and Kinematics of Radio-Loud Narrow-Line Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Richards, Joseph L; Lister, Matthew L.; Foschini, Luigi; Savolainen, Tuomas; Homan, Daniel C.; Kadler, Matthias; Readhead, Anthony C. S.; Arshakian, Tigran; Chavushyan, Vahram

    2014-08-01

    We have begun a campaign to monitor a sample of 15 radio-loud narrow-line Seyfert 1 galaxies (NLS1s) with the Very Long Baseline Array (VLBA). Here, we present early results from this program, which includes total intensity and polarimetric observations at 1, 2, 4, and 6cm wavelengths. NLS1s are a class of active galactic nuclei that share many observational properties with the much more powerful blazar classes. Despite their low black hole masses and near- or super-Eddington accretion rates, a small minority are radio loud. A growing number of these have been detected in GeV gamma rays, indicating that a relativistic jet has formed in at least some of these sources. This presents a challenge to jet models, but may provide a link between jets found at the small scales of galactic binaries and the large scales of giant quasars. In addition to our VLBA program, we are carrying out complementary fast-cadence single dish 2cm radio monitoring with the Owens Valley Radio Observatory 40m telescope and an optical spectroscopic monitoring campaign using the Guillermo Haro Astrophysics Observatory 2m-class telescope in Cananea, Mexico. Using data from this program, we will expand the currently limited knowledge of the parsec-scale properties and kinematics of this class of sources. Among our first epoch results, we find significant parsec-scale extension in about about two thirds of our sample, many of which are excellent candidates for jet kinematics analysis.

  18. The parsec-scale structure, kinematics, and polarization of radio-loud narrow-line Seyfert 1 galaxies

    NASA Astrophysics Data System (ADS)

    Richards, J. L.; Lister, M. L.; Savolainen, T.; Homan, D. C.; Kadler, M.; Hovatta, T.; Readhead, A. C. S.; Arshakian, T. G.; Chavushyan, V.

    2015-03-01

    Several narrow-line Seyfert 1 galaxies (NLS1s) have now been detected in gamma rays, providing firm evidence that at least some of this class of active galactic nuclei (AGN) produce relativistic jets. The presence of jets in NLS1s is surprising, as these sources are typified by comparatively small black hole masses and near- or super-Eddington accretion rates. This challenges the current understanding of the conditions necessary for jet production. Comparing the properties of the jets in NLS1s with those in more familiar jetted systems is thus essential to improve jet production models. We present early results from our campaign to monitor the kinematics and polarization of the parsec-scale jets in a sample of 15 NLS1s through multifrequency observations with the Very Long Baseline Array. These observations are complemented by fast-cadence 15 GHz monitoring with the Owens Valley Radio Observatory 40 m telescope and optical spectroscopic monitoring with with the 2 m class telescope at the Guillermo Haro Astrophysics Observatory in Cananea, Mexico.

  19. Zooming in on the peculiar radio-loud narrow-line Seyfert 1 galaxy, J1100+4421

    NASA Astrophysics Data System (ADS)

    Gabányu, K. É.; Frey, S.; Paragi, Z.; Tar, I.; An, T.; Tanaka, M.; Morokuma, T.

    2016-08-01

    Narrow-line Seyfert 1 galaxies (NLS1) are interesting subsamples of active galactic nuclei, which are typically thought to contain a relatively smaller supermassive black holes (10^6-10^8 solar masses) and show quite high accretion rate. Only 7% of them are detected in radio. The radio structure of the objects in the extremely radio-loud NLS1 subsample indicates the presence of relativistically beamed jets. Some radio-loud NLS1s were detected even at high energies with the Fermi Large Array Telescope. Therefore these sources are often suggested to be the low-luminosity and younger counterparts of blazars. SDSS J110006.07+442144.3 was identified as an NLS1 at z=0.84 after its dramatic optical brightening discovered by Tanaka et al. (2014) Our dual-frequency (1.6 and 5 GHz) European VLBI Network observations taken one year after this event show a compact structre with brightness temperature of 6 x 10^9 K and a flat spectral index indicating the presence of a compact synchrotron self-absorbed core. Compared with low resolution VLA-FIRST data, the large-scale structure seen there is resolved out in the EVN observation. However the recovered flux density in our L-band EVN observation is significantly higher than the FIRST flux density, which is indicative of brightening in the radio regime. All these results fit into the picture where radio-loud NLS1s are described as faint blazars.

  20. 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}⊙ , 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.

  1. A population of massive, luminous galaxies hosting heavily dust-obscured gamma-ray bursts: Implications for the use of GRBs as tracers of cosmic star formation

    SciTech Connect

    Perley, D. A.; Levan, A. J.; Tanvir, N. R.; Cenko, S. B.; Bloom, J. S.; Filippenko, A. V.; Morgan, A. N.; Hjorth, J.; Krühler, T.; Fynbo, J. P. U.; Milvang-Jensen, B.; Fruchter, A.; Kalirai, J.; Jakobsson, P.; Prochaska, J. X.

    2013-12-01

    We present observations and analysis of the host galaxies of 23 heavily dust-obscured gamma-ray bursts (GRBs) observed by the Swift satellite during the years 2005-2009, representing all GRBs with an unambiguous host-frame extinction of A{sub V} > 1 mag from this period. Deep observations with Keck, Gemini, Very Large Telescope, Hubble Space Telescope, and Spitzer successfully detect the host galaxies and establish spectroscopic or photometric redshifts for all 23 events, enabling us to provide measurements of the intrinsic host star formation rates, stellar masses, and mean extinctions. Compared to the hosts of unobscured GRBs at similar redshifts, we find that the hosts of dust-obscured GRBs are (on average) more massive by about an order of magnitude and also more rapidly star forming and dust obscured. While this demonstrates that GRBs populate all types of star-forming galaxies, including the most massive, luminous systems at z ≈ 2, at redshifts below 1.5 the overall GRB population continues to show a highly significant aversion to massive galaxies and a preference for low-mass systems relative to what would be expected given a purely star-formation-rate-selected galaxy sample. This supports the notion that the GRB rate is strongly dependent on metallicity, and may suggest that the most massive galaxies in the universe underwent a transition in their chemical properties ∼9 Gyr ago. We also conclude that, based on the absence of unobscured GRBs in massive galaxies and the absence of obscured GRBs in low-mass galaxies, the dust distributions of the lowest-mass and the highest-mass galaxies are relatively homogeneous, while intermediate-mass galaxies (∼10{sup 9} M {sub ☉}) have diverse internal properties.

  2. 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.

  3. The UV variability of the Seyfert 1: Galaxies 3 Zw 2 and Markarian 509

    NASA Technical Reports Server (NTRS)

    Huchra, J.; Geller, M.; Merton, D.

    1981-01-01

    The two galaxies differ markedly in their radio properties. III Zw 2 is a strong source with a highly variable compact component while MK 509 is a very weak source. Both galaxies show significant variations in X-rays and MK 509 has shown variations at optical wavelengths as well. Simultaneous observations were made in the ultraviolet, optical and infrared in order to examine three fundamental aspects of the origin of the continuum emission: are these thermal and nonthermal components; how large is the emitting region; and does the UV flux originate in the same region responsible for the optical, IR, radio and/or X-ray continuum emission?

  4. Discovering highly obscured AGN with the Swift-BAT 100-month survey

    NASA Astrophysics Data System (ADS)

    Marchesi, Stefano; Ajello, Marco; Comastri, Andrea; Cusumano, Giancarlo; La Parola, Valentina; Segreto, Alberto

    2017-01-01

    In this talk, I present a new technique to find highly obscured AGN using the 100-month Swift-BAT survey. I will show the results of the combined Chandra and BAT spectral analysis in the 0.3-150 keV band of seven Seyfert 2 galaxies selected from the 100-month BAT catalog. We selected nearby (z<0.03) sources lacking of a ROSAT counterpart and never previously observed in the 0.3-10 keV energy range. All the objects are significantly obscured, having NH>1E23 cm-2 at a >99% confidence level, and one to three sources are candidate Compton thick Active Galactic Nuclei (CT-AGN), i.e., have NH>1E24 cm-2.Since the selection criteria we adopted have been extremely effective in detecting highly obscured AGN, further observations of these and other Seyfert 2 galaxies selected from the BAT 100-month catalog will allow us to create a statistically significant sample of highly obscured AGN, therefore better understanding the physics of the obscuration processes.

  5. THE BULGELESS SEYFERT/LINER GALAXY NGC 3367: DISK, BAR, LOPSIDEDNESS, AND ENVIRONMENT

    SciTech Connect

    Hernandez-Toledo, H. M.; Cano-Diaz, M.; Valenzuela, O.; Garcia-Barreto, J. A; Moreno-Diaz, E.; Puerari, I.; Bravo-Alfaro, H.

    2011-12-15

    NGC 3367 is a nearby isolated active galaxy that shows a radio jet, a strong bar, and evidence of lopsidedness. We present a quantitative analysis of the stellar and gaseous structure of the galaxy disk and search for evidence of recent interaction. Our study is based on new UBVRI H{alpha} and JHK images and on archive H{alpha} Fabry-Perot and H I Very Large Array data. From a coupled one-dimensional/two-dimensional GALFIT bulge/bar/disk decomposition a (B/D {approx} 0.07-0.1) exponential pseudobulge is inferred in all the observed bands. A near-infrared (NIR) estimate of the bar strength Q{sup max}{sub T}(R) = 0.44 places NGC 3367 bar among the strongest ones. The asymmetry properties were studied using (1) the optical and NIR concentration-asymmetry-clumpiness indices, (2) the stellar (NIR) and gaseous (H{alpha}, H I) A{sub 1} Fourier mode amplitudes, and (3) the H I-integrated profile and H I mean intensity distribution. While the average stellar component shows asymmetry values close to the average found in the local universe for isolated galaxies, the young stellar component and gas values are largely decoupled showing significantly larger A{sub 1} mode amplitudes suggesting that the gas has been recently perturbed and placing NGC 3367 in a global starburst phase. NGC 3367 is devoid of H I gas in the central regions where a significant amount of molecular CO gas exists instead. Our search for (1) faint stellar structures in the outer regions (up to {mu}{sub R} {approx} 26 mag arcsec{sup -2}), (2) (H{alpha}) star-forming satellite galaxies, and (3) regions with different colors (stellar populations) along the disk all failed. Such an absence is interpreted by using results from recent numerical simulations to constrain either a possible tidal event with an LMC like galaxy to some dynamical times in the past or a very low mass but perhaps gas rich recent encounter. We conclude that a cold flow accretion mode (gas and small/dark galaxies) may be responsible for

  6. Distributions 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, Shuro; Nakajima, Taku; Kohno, Kotaro; Harada, Nanase; Herbst, Eric; Tamura, Yoichi; Izumi, Takuma; Taniguchi, Akio; Tosaki, Tomoka

    2014-07-01

    Sensitive observations with the Atacama Large Millimeter/submillimeter Array (ALMA) allow astronomers to observe the detailed distributions of molecules with relatively weak intensity in nearby galaxies. In particular, we report distributions of several molecular transitions including shock and dust related species (13CO J = 1-0, 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 the ALMA early science program. The central ˜ 1'(˜ 4.3 kpc) of this galaxy was observed in the 100-GHz region covering ˜ 96-100 GHz and ˜ 108-111 GHz with an angular resolution of ˜ 4'' × 2'' (290 pc × 140 pc) to study the effects of an active galactic nucleus and its surrounding starburst ring on molecular abundances. Here, we present images and report a classification of molecular distributions into three main categories: (1) molecules concentrated in the circumnuclear disk (CND) (SO JN = 32-21, HC3N J = 11-10, 12-11, and CH3CN JK = 6K-5K), (2) molecules distributed both in the CND and the starburst ring (CS J = 2-1 and CH3OH JK = 2K-1K), and (3) molecules distributed mainly in the starburst ring (13CO J = 1-0 and C18O J = 1-0). Since most of the molecules such as HC3N observed in the CND are easily dissociated by UV photons and X-rays, our results indicate that these molecules must be effectively shielded. In the starburst ring, the relative intensity of methanol at each clumpy region is not consistent with those of 13CO, C18O, or CS. This difference is probably caused by the unique formation and destruction mechanisms of CH3OH.

  7. CO observations of the SAB galaxies NGC 157, 2903, 4321, and 5248, and the Seyfert galaxy NGC 1068

    NASA Astrophysics Data System (ADS)

    Elmegreen, D. M.; Elmegreen, B. G.

    1982-04-01

    Extragalactic carbon monoxide emission regions can, in principle, be located more precisely than the telescope beamwidth by using optically derived velocity distributions which have much higher angular resolution. Using this technique, the CO emission from five distant galaxies was analyzed. CO emission from NGC 1068 is strongest in the central region. In NGC 4321, it is strongest in the long bright spiral arms. CO emission from NGC 157 and NGC 2903 occurs more uniformly over the disk of these galaxies; the H II regions and dust clouds are more uniformly distributed in these galaxies as well. In NGC 157, the CO is brightest from the area including the NE spiral arm, which has more continuity and bright star formation than the SW arm. These results agree with the expectation that CO emission should be intensified near the H II regions and obvious dust clouds that usually concentrate near the spiral arms.

  8. 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

  9. An extended XMM-Newton observation of the Seyfert galaxy NGC 4051 - III. Fe K emission and absorption

    NASA Astrophysics Data System (ADS)

    Pounds, K. A.; Vaughan, S.

    2012-06-01

    An extended XMM-Newton observation of the Seyfert 1 galaxy NGC 4051 in 2009 detected a photoionized outflow with a complex absorption-line velocity structure and a broad correlation of velocity with ionization parameter, shown by Pounds & Vaughan to be consistent with a highly ionized, high-velocity wind running into the interstellar medium or previous ejecta, losing much of its kinetic energy in the resultant strong shock. In this paper, we examine the Fe K spectral region in more detail and find support for two distinct velocity components in the highly ionized absorber, with values corresponding to the putative fast wind (˜0.12c) and the post-shock flow (v˜ 5000-7000 km s-1). The Fe K absorption-line structure is seen to vary on a orbit-to-orbit time-scale, apparently responding to both a short-term increase in ionizing flux and - perhaps more generally - to changes in the soft X-ray (and simultaneous ultraviolet) luminosity. The latter result is particularly interesting in providing independent support for the existence of shocked gas being cooled primarily by Compton scattering of accretion disc photons. The Fe K emission is represented by a narrow fluorescent line from near-neutral matter, with a weak red wing modelled here by a relativistic DISKLINE. The narrow line flux is quasi-constant throughout the 45-d 2009 campaign, but is resolved, with a velocity width consistent with scattering from a component of the post-shock flow. Evidence for a P Cygni profile is seen in several individual orbit spectra for resonance transitions in both Fe XXV and Fe XXVI.

  10. A POSSIBLE ULTRA STRONG AND BROAD Fe K{alpha} EMISSION LINE IN SEYFERT 2 GALAXY IRAS 00521-7054

    SciTech Connect

    Tan, Y.; Wang, J. X.; Shu, X. W.; Zhou Youyuan E-mail: jxw@ustc.edu.cn E-mail: yyzhou@ustc.edu.cn

    2012-03-15

    We present XMM-Newton spectra of the Seyfert 2 Galaxy IRAS 00521-7054. A strong feature at {approx}6 keV (observer's frame) can be formally fitted with a strong (EW = 1.3 {+-} 0.3 keV in the rest frame) and broad Fe K{alpha} line, extending down to 3 keV. The underlying X-ray continuum could be fitted with an absorbed power law (with {Gamma} = 1.8 {+-} 0.2 and N{sub H} 5.9{sup +0.6}{sub -0.7} Multiplication-Sign 10{sup 22} cm{sup -2}) plus a soft component. If due to relativistically smeared reflection by an X-ray illuminated accretion disk, the spin of the supermassive black hole (SMBH) is constrained to be 0.97{sup +0.03}{sub -0.13} (errors at 90% confidence level for one interesting parameter), and the accretion system is viewed at an inclination angle of 37 Degree-Sign {+-} 4 Degree-Sign . This would be the first type 2 active galactic nucleus reported with strong red Fe K{alpha} wing detected which demands a fast rotating SMBH. The unusually large EW would suggest that the light bending effect is strong in this source. Alternatively, the spectra could be fitted by a dual-absorber model (though with a global {chi}{sup 2} higher by {approx}6 for 283 dof) with N{sub H1} 7.0 {+-} 0.8 Multiplication-Sign 10{sup 22} cm{sup -2} covering 100% of the X-ray source, and N{sub H2} = 21.7{sup +5.6}{sub -5.4} Multiplication-Sign 10{sup 22} cm{sup -2} covering 71%, which does not require an extra broad Fe K{alpha} line.

  11. 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.

  12. 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.

  13. SDSSJ143244.91+301435.3 at VLBI: a compact radio galaxy in a narrow-line Seyfert 1

    NASA Astrophysics Data System (ADS)

    Caccianiga, A.; Dallacasa, D.; Antón, S.; Ballo, L.; Berton, M.; Mack, K.-H.; Paulino-Afonso, A.

    2017-01-01

    We present very long baseline interferometry (VLBI) observations, carried out with the European Very Long Baseline Interferometry Network (EVN), of SDSSJ143244.91+301435.3, a radio-loud narrow-line Seyfert 1 (RL NLS1) characterized by a steep radio spectrum. The source, compact at Very Large Array resolution, is resolved on the milliarcsec scale, showing a central region plus two extended structures. The relatively high brightness temperature of all components (5 × 106-1.3 × 108 K) supports the hypothesis that the radio emission is non-thermal and likely produced by a relativistic jet and/or small radio lobes. The observed radio morphology, the lack of a significant core, and the presence of a low frequency (230 MHz) spectral turnover are reminiscent of the Compact Steep-Spectrum (CSS) sources. However, the linear size of the source (˜0.5 kpc) measured from the EVN map is lower than the value predicted using the turnover/size relation valid for CSS sources (˜6 kpc). This discrepancy can be explained by an additional component not detected in our observations, accounting for about a quarter of the total source flux density, combined to projection effects. The low core dominance of the source (CD < 0.29) confirms that SDSSJ143244.91+301435.3 is not a blazar, i.e. the relativistic jet is not pointing towards the observer. This supports the idea that SDSSJ143244.91+301435.3 may belong to the `parent population' of flat-spectrum RL NLS1 and favours the hypothesis of a direct link between RL NLS1 and compact, possibly young, radio galaxies.

  14. Near-Infrared Spectroscopic Analysis of Galaxy Mergers: Revealing Obscured Accretion

    NASA Astrophysics Data System (ADS)

    Ferguson, Jason; Constantin, Anca; Satyapal, Shobita; Rothberg, Barry

    2017-01-01

    Galaxy interactions are ubiquitous and are believed to play a pivotal role in the formation and evolution of galaxies via facilitating gas inflows toward the central region of galaxies. These interactions are expected to trigger accretion of matter onto the central supermassive black holes, i.e., AGN activity. Nevertheless, despite decades of searching, observationally confirmed dual AGNs remain extremely rare. We present here a thorough near-infrared characterization of six examples of interacting galaxies with unambiguous confirmation of on-going mergers that are optically quiescent but have red mid-infrared colors that are associated with extragalactic sources with powerful AGN. We show Large Binocular Telescope spectra of nuclear regions that reveal a rich variety of emission and absorption features which allow us to explore several diagnostic tests for the AGN activity as well as for properties of the underlying stellar population. We find strong evidence for AGN emission in five out of these six interacting systems, which provides strong support for the efficiency with which the mid-infrared pre-selection technique finds dual AGN, and thus could exponentially increase the population of dual accretion systems in advanced mergers.

  15. 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.

  16. High-z X-ray Obscured Quasars in Galaxies with Extreme Mid-IR/Optical Colors

    NASA Astrophysics Data System (ADS)

    Piconcelli, E.; Lanzuisi, G.; Fiore, F.; Feruglio, C.; Vignali, C.; Salvato, M.; Grappioni, C.

    2009-05-01

    Extreme Optical/Mid-IR color cuts have been used to uncover a population of dust-enshrouded, mid-IR luminous galaxies at high redshifts. Several lines of evidence point towards the presence of an heavily absorbed, possibly Compton-thick quasar at the heart of these systems. Nonetheless, the X-ray spectral properties of these intriguing sources still remain largely unexplored. Here we present an X-ray spectroscopic study of a large sample of 44 extreme dust-obscured galaxies (EDOGs) with F24 μm/FR>2000 and F24 μm>1.3 mJy selected from a 6 deg2 region in the SWIRE fields. The application of our selection criteria to a wide area survey has been capable of unveiling a population of X-ray luminous, absorbed z>1 quasars which is mostly missed in the traditional optical/X-ray surveys performed so far. Advances in the understanding of the X-ray properties of these recently-discovered sources by Simbol-X observations will be also discussed.

  17. HIGH-REDSHIFT DUST OBSCURED GALAXIES: A MORPHOLOGY-SPECTRAL ENERGY DISTRIBUTION CONNECTION REVEALED BY KECK ADAPTIVE OPTICS

    SciTech Connect

    Melbourne, J.; Matthews, K.; Soifer, B. T. E-mail: bts@submm.caltech.edu

    2009-06-15

    A simple optical to mid-IR color selection, R - [24]>14, i.e., f {sub {nu}}(24 {mu}m)/f {sub {nu}}(R) {approx}> 1000, identifies highly dust obscured galaxies (DOGs) with typical redshifts of z {approx} 2 {+-} 0.5. Extreme mid-IR luminosities (L {sub IR} > 10{sup 12-14}) suggest that DOGs are powered by a combination of active galactic nuclei (AGNs) and star formation, possibly driven by mergers. In an effort to compare their photometric properties with their rest-frame optical morphologies, we obtained high-spatial resolution (0.''05-0.''1) Keck Adaptive Optics K'-band images of 15 DOGs. The images reveal a wide range of morphologies, including small exponential disks (eight of 15), small ellipticals (four of 15), and unresolved sources (two of 15). One particularly diffuse source could not be classified because of low signal-to-noise ratio. We find a statistically significant correlation between galaxy concentration and mid-IR luminosity, with the most luminous DOGs exhibiting higher concentration and smaller physical size. DOGs with high concentration also tend to have spectral energy distributions (SEDs) suggestive of AGN activity. Thus, central AGN light may be biasing the morphologies of the more luminous DOGs to higher concentration. Conversely, more diffuse DOGs tend to show an SED shape suggestive of star formation. Two of 15 in the sample show multiple resolved components with separations of {approx}1 kpc, circumstantial evidence for ongoing mergers.

  18. Galaxy Evolution at High Redshift: Obscured Star Formation, GRB Rates, Cosmic Reionization, and Missing Satellites

    NASA Astrophysics Data System (ADS)

    Lapi, A.; Mancuso, C.; Celotti, A.; Danese, L.

    2017-01-01

    We provide a holistic view of galaxy evolution at high redshifts z ≳ 4, which incorporates the constraints from various astrophysical/cosmological probes, including the estimate of the cosmic star formation rate (SFR) density from UV/IR surveys and long gamma-ray burst (GRBs) rates, the cosmic reionization history following the latest Planck measurements, and the missing satellites issue. We achieve this goal in a model-independent way by exploiting the SFR functions derived by Mancuso et al. on the basis of an educated extrapolation of the latest UV/far-IR data from HST/Herschel, and already tested against a number of independent observables. Our SFR functions integrated down to a UV magnitude limit MUV ≲ ‑13 (or SFR limit around 10‑2 M⊙ yr‑1) produce a cosmic SFR density in excellent agreement with recent determinations from IR surveys and, taking into account a metallicity ceiling Z ≲ Z⊙/2, with the estimates from long GRB rates. They also yield a cosmic reionization history consistent with that implied by the recent measurements of the Planck mission of the electron scattering optical depth τes ≈ 0.058 remarkably, this result is obtained under a conceivable assumption regarding the average value fesc ≈ 0.1 of the escape fraction for ionizing photons. We demonstrate via the abundance-matching technique that the above constraints concurrently imply galaxy formation becoming inefficient within dark matter halos of mass below a few 108 M⊙ pleasingly, such a limit is also required so as not to run into the missing satellites issue. Finally, we predict a downturn of the Galaxy luminosity function faintward of MUV ≲ ‑12, and stress that its detailed shape, to be plausibly probed in the near future by the JWST, will be extremely informative on the astrophysics of galaxy formation in small halos, or even on the microscopic nature of the dark matter.

  19. 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.

  20. 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.

  1. ALMA HCN and HCO+ J =3-2 Observations of Optical Seyfert and Luminous Infrared Galaxies: Confirmation of Elevated HCN-to-HCO+ Flux Ratios in AGNs

    NASA Astrophysics Data System (ADS)

    Imanishi, Masatoshi; Nakanishi, Kouichiro; Izumi, Takuma

    2016-12-01

    We present the results of our ALMA observations of three active galactic nucleus (AGN)-dominated nuclei in optical Seyfert 1 galaxies (NGC 7469, I Zw 1, and IC 4329 A) and eleven luminous infrared galaxies (LIRGs) with various levels of infrared estimated energetic contributions by AGNs at the HCN and HCO+ J = 3 - 2 emission lines. The HCN and HCO+ J = 3 - 2 emission lines are clearly detected at the main nuclei of all sources, except for IC 4329 A. The vibrationally excited (v 2 = 1f) HCN J = 3 - 2 and HCO+ J = 3 - 2 emission lines are simultaneously covered, and HCN v 2 = 1f J = 3 - 2 emission line signatures are seen in the main nuclei of two LIRGs, IRAS 12112+0305 and IRAS 22491-1808, neither of which shows clear buried AGN signatures in the infrared. If the vibrational excitation is dominated by infrared radiative pumping, through the absorption of infrared 14 μm photons, primarily originating from AGN-heated hot dust emission, then these two LIRGs may contain infrared-elusive, but (sub)millimeter-detectable, extremely deeply buried AGNs. These vibrationally excited emission lines are not detected in the three AGN-dominated optical Seyfert 1 nuclei. However, the observed HCN v 2 = 1f to v = 0 flux ratios in these optical Seyferts are still consistent with the intrinsic flux ratios in LIRGs with detectable HCN v 2 = 1f emission lines. The observed HCN-to-HCO+ J = 3 - 2 flux ratios tend to be higher in galactic nuclei with luminous AGN signatures compared with starburst-dominated regions, as previously seen at J = 1 - 0 and J = 4 - 3.

  2. How Simbol-X Will Reveal the Most Obscured High Energy Sources of our Galaxy

    NASA Astrophysics Data System (ADS)

    Chaty, S.

    2009-05-01

    The INTEGRAL satellite has revealed a major population of supergiant High Mass X-ray Binaries in our Galaxy, revolutionizing our understanding of binary systems and their evolution. This population, constituted of a compact object orbiting around a supergiant star, have unusual properties, either being extremely absorbed, or exhibiting very short flares. I will first describe the characteristics of these sources, that only intensive multi-wavelength observations have led us to disentangle, before showing that Simbol-X, thanks to its energy range and sensitivity, will allow us to go further in the understanding of these supergiant HMXBs.

  3. How Simbol-X Will Reveal the Most Obscured High Energy Sources of our Galaxy

    SciTech Connect

    Chaty, S.

    2009-05-11

    The INTEGRAL satellite has revealed a major population of supergiant High Mass X-ray Binaries in our Galaxy, revolutionizing our understanding of binary systems and their evolution. This population, constituted of a compact object orbiting around a supergiant star, have unusual properties, either being extremely absorbed, or exhibiting very short flares. I will first describe the characteristics of these sources, that only intensive multi-wavelength observations have led us to disentangle, before showing that Simbol-X, thanks to its energy range and sensitivity, will allow us to go further in the understanding of these supergiant HMXBs.

  4. 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.

  5. Radio jets and high velocity gas in the Seyfert Galaxy NGC 1068

    NASA Astrophysics Data System (ADS)

    Wilson, A. S.; Ulvestad, J. S.

    1983-12-01

    New, high sensitivity VLA maps of the central regions of NGC 1068 at 4.9 GHz (total intensity and linear polarization) and 15.0 GHz (total intensity only) are presented. As found by van der Hulst, Hummel, and Dickey (1982), the bright radio emission coincident with the galaxy nucleus is resolved into a bent triple of total extent 0.7 arcsec, with the central source apparently associated with the nucleus proper. It is found that the 13 arcsec scale linear source comprises oppositely directed radio jets feeding a 'hot spot' and radio lobes. The radio emission of the NE lobe seems to be concentrated near the surface of a conically shaped region, which is also closely associated with some of the high velocity, optical line emitting clouds, and may relate to a bow shock, blast wave, or cocoon of material shed by the jet as it propagates through the interstellar medium. Two models for the ionization of the optical clouds are discussed either ionizing photons eacape preferentially along the rotation axis of the disk which collimates the radio jets, or the excitation is effected by the kinetic energy of the jets or lobes themselves.

  6. 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.

  7. NuSTAR Observations of WISE J1036+0449, a Galaxy at z~1 Obscured by Hot Dust

    NASA Astrophysics Data System (ADS)

    Ricci, C.; Assef, R. J.; Stern, D.; Nikutta, R.; Alexander, D. M.; Asmus, D.; Ballantyne, D. R.; Bauer, F. E.; Blain, A. W.; Boggs, S.; Boorman, P. G.; Brandt, W. N.; Brightman, M.; Chang, C. S.; Chen, C.-T. J.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Díaz-Santos, T.; Eisenhardt, P. R.; Farrah, D.; Gandhi, P.; Hailey, C. J.; Harrison, F. A.; Jun, H. D.; Koss, M. J.; LaMassa, S.; Lansbury, G. B.; Markwardt, C. B.; Stalevski, M.; Stanley, F.; Treister, E.; Tsai, C.-W.; Walton, D. J.; Wu, J. W.; Zappacosta, L.; Zhang, W. W.

    2017-01-01

    Hot dust-obscured galaxies (hot DOGs), selected from Wide-Field Infrared Survey Explorer’s all-sky infrared survey, host some of the most powerful active galactic nuclei known and may represent an important stage in the evolution of galaxies. Most known hot DOGs are located at z> 1.5, due in part to a strong bias against identifying them at lower redshift related to the selection criteria. We present a new selection method that identifies 153 hot DOG candidates at z∼ 1, where they are significantly brighter and easier to study. We validate this approach by measuring a redshift z = 1.009 and finding a spectral energy distribution similar to that of higher-redshift hot DOGs for one of these objects, WISE J1036+0449 ({L}{Bol}≃ 8× {10}46 {erg} {{{s}}}-1). We find evidence of a broadened component in Mg ii, which would imply a black hole mass of {M}{BH}≃ 2× {10}8 {M}ȯ and an Eddington ratio of {λ }{Edd}≃ 2.7. WISE J1036+0449 is the first hot DOG detected by the Nuclear Spectroscopic Telescope Array, and observations show that the source is heavily obscured, with a column density of {N}{{H}}≃ (2{--}15)× {10}23 {{cm}}-2. The source has an intrinsic 2–10 keV luminosity of ∼ 6× {10}44 {erg} {{{s}}}-1, a value significantly lower than that expected from the mid-infrared/X-ray correlation. We also find that other hot DOGs observed by X-ray facilities show a similar deficiency of X-ray flux. We discuss the origin of the X-ray weakness and the absorption properties of hot DOGs. Hot DOGs at z≲ 1 could be excellent laboratories to probe the characteristics of the accretion flow and of the X-ray emitting plasma at extreme values of the Eddington ratio.

  8. EMERGENCE OF A BROAD ABSORPTION LINE OUTFLOW IN THE NARROW-LINE SEYFERT 1 GALAXY WPVS 007

    SciTech Connect

    Leighly, Karen M.; Casebeer, Darrin A.; Hamann, Fred; Grupe, Dirk

    2009-08-10

    We report results from a 2003 Far Ultraviolet Spectroscopic Explorer (FUSE) observation and reanalysis of a 1996 Hubble Space Telescope (HST) observation of the unusual X-ray transient Narrow-line Seyfert 1 galaxy WPVS 007. The HST Faint Object Spectrograph (FOS) spectrum revealed mini-BALs (broad absorption lines) with V {sub max} {approx} 900 km s{sup -1} and FWHM {approx}550 km s{sup -1}. The FUSE spectrum showed that an additional BAL outflow with V {sub max} {approx} 6000 km s{sup -1} and FWHM {approx}3400 km s{sup -1} had appeared. WPVS 007 is a low-luminosity object in which such a high-velocity outflow is not expected; therefore, it is an outlier on the M{sub V} /v {sub max} relationship. Template spectral fitting yielded apparent ionic columns, and a Cloudy analysis showed that the presence of P V requires a high-ionization parameter log(U) {>=} 0 and high-column density log(N {sub H}) {>=} 23 assuming solar abundances and a nominal spectral energy distribution (SED) for low-luminosity NLS1s with {alpha} {sub ox} = -1.28. A recent long Swift observation revealed the first hard X-ray detection and an intrinsic (unabsorbed) {alpha} {sub ox} {approx} -1.9. Using this SED in our analysis yielded lower column density constraints (log(N {sub H}) {>=} 22.2 for Z = 1, or log(N {sub H}) {>=} 21.6 if Z = 5). The X-ray weak continuum, combined with X-ray absorption consistent with the UV lines, provides the best explanation for the observed Swift X-ray spectrum. The large column densities and velocities implied by the UV data in any of these scenarios could be problematic for radiative acceleration. We also point out that since the observed P V absorption can be explained by lower total column densities using an intrinsically X-ray weak spectrum, we might expect to find P V absorption preferentially more often (or stronger) in quasars that are intrinsically X-ray weak.

  9. 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

  10. Submillimeter Line Spectrum of the Seyfert Galaxy NGC 1068 from the Herschel-SPIRE Fourier Transform Spectrometer

    NASA Astrophysics Data System (ADS)

    Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma; Schirm, Maximilien R. P.; Wilson, Christine D.; Glenn, Jason; Kamenetzky, Julia; Rangwala, Naseem; Maloney, Philip R.; Parkin, Tara J.; Bendo, George J.; Madden, Suzanne C.; Wolfire, Mark G.; Boselli, Alessandro; Cooray, Asantha; Page, Mathew J.

    2012-10-01

    The first complete submillimeter spectrum (190-670 μm) 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 up = 4-13), lines from H2O, the fundamental rotational transition of hydrogen fluoride, two o-H2O+ lines, and one line each from CH+ and OH+ have been detected, together with the two [C I] lines and the [N II] 205 μm 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(H2) = 104.5 and 102.9 cm-3 and temperatures of T 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(H2) ~ 104 cm-3 and an X-ray flux of 9 erg s-1 cm-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 kin ~ 40 K) and high density (n(H2) in the range 106.7-107.9 cm-3). The emission of H2O+ and OH+ are in agreement with PDR models with cosmic-ray ionization. The diffuse ionized atomic component observed through the [N II] 205 μm line is consistent with previous photoionization models of the starburst. Herschel is an ESA space observatory with science instruments provided by

  11. 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

  12. The broad-line region and dust torus size of the Seyfert 1 galaxy PGC 50427

    NASA Astrophysics Data System (ADS)

    Pozo Nuñez, F.; Ramolla, M.; Westhues, C.; Haas, M.; Chini, R.; Steenbrugge, K.; Barr Domínguez, A.; Kaderhandt, L.; Hackstein, M.; Kollatschny, W.; Zetzl, M.; Hodapp, K. W.; Murphy, M.

    2015-04-01

    We present the results of three-year monitoring campaigns of the z = 0.024 type 1 active Galactic nucleus (AGN) PGC 50427. Using robotic telescopes of the Universitätssternwarte Bochum near Cerro Armazones in Chile, we monitored PGC 50427 in the optical and near-infrared (NIR). Through the use of photometric reverberation mapping with broad- and narrowband filters, we determine the size of the broad-line emitting region by measuring the time delay between the variability of the continuum and the Hα emission line. The Hα emission line responds to blue continuum variations with an average rest frame lag of 19.0 ± 1.23 days. Using single epoch spectroscopy obtained with the Southern African Large Telescope (SALT) we determined a broad-line Hα velocity width of 1020 km s-1 and in combination with the rest frame lag and adoption of a geometric scaling factor f = 5.5, we calculate a black hole mass of MBH ~ 17 × 106 M⊙. Using the flux variation gradient method, we separate the host galaxy contribution from that of the AGN to calculate the rest frame 5100 Å luminosity at the time of our monitoring campaign. We measured small luminosity variations in the AGN (~10%) accross the three years of the monitoring campaign. The rest frame lag and the host-subtracted luminosity permit us to derive the position of PGC 50427 in the BLR size - AGN luminosity diagram, which is remarkably close to the theoretically expected relation of R ∝ L0.5. The simultaneous optical and NIR (J and Ks) observations allow us to determine the size of the dust torus through the use of dust reverberation mapping method. We find that the hot dust emission (~1800 K) lags the optical variations with an average rest frame lag of 46.2 ± 2.60 days. The dust reverberation radius and the nuclear NIR luminosity permit us to derive the position of PGC 50427 on the known τ - MV diagram. The simultaneous observations for the broad-line region and dust thermal emission demonstrate that the innermost dust

  13. SPIRITS 15c and SPIRITS 14buu: Two Obscured Supernovae in the Nearby Star-forming Galaxy IC 2163

    NASA Astrophysics Data System (ADS)

    Jencson, Jacob E.; Kasliwal, Mansi M.; Johansson, Joel; Contreras, Carlos; Castellón, Sergio; Bond, Howard E.; Monson, Andrew J.; Masci, Frank J.; Cody, Ann Marie; Andrews, Jennifer E.; Bally, John; Cao, Yi; Fox, Ori D.; Gburek, Timothy; Gehrz, Robert D.; Green, Wayne; Helou, George; Hsiao, Eric; Morrell, Nidia; Phillips, Mark; Prince, Thomas A.; Simcoe, Robert A.; Smith, Nathan; Tinyanont, Samaporn; Williams, Robert

    2017-03-01

    SPitzer InfraRed Intensive Transients Survey—SPIRITS—is an ongoing survey of nearby galaxies searching for infrared (IR) transients with Spitzer/IRAC. We present the discovery and follow-up observations of one of our most luminous (M [4.5] = ‑17.1 ± 0.4 mag, Vega) and reddest ([3.6] ‑ [4.5] = 3.0 ± 0.2 mag) transients, SPIRITS 15c. The transient was detected in a dusty spiral arm of IC 2163 (D ≈ 35.5 Mpc). Pre-discovery ground-based imaging revealed an associated, shorter-duration transient in the optical and near-IR (NIR). NIR spectroscopy showed a broad (≈8400 km s‑1), double-peaked emission line of He i at 1.083 μm, indicating an explosive origin. The NIR spectrum of SPIRITS 15c is similar to that of the Type IIb SN 2011dh at a phase of ≈200 days. Assuming an A V = 2.2 mag of extinction in SPIRITS 15c provides a good match between their optical light curves. The NIR light curves, however, show some minor discrepancies when compared with SN 2011dh, and the extreme [3.6]–[4.5] color has not been previously observed for any SN IIb. Another luminous (M 4.5 = ‑16.1 ± 0.4 mag) event, SPIRITS 14buu, was serendipitously discovered in the same galaxy. The source displays an optical plateau lasting ≳80 days, and we suggest a scenario similar to the low-luminosity Type IIP SN 2005cs obscured by A V ≈ 1.5 mag. Other classes of IR-luminous transients can likely be ruled out in both cases. If both events are indeed SNe, this may suggest that ≳18% of nearby core-collapse SNe are missed by currently operating optical surveys.

  14. Hyper-luminous dust-obscured galaxies discovered by the Hyper Suprime-Cam on Subaru and WISE

    NASA Astrophysics Data System (ADS)

    Toba, Yoshiki; Nagao, Tohru; Strauss, Michael A.; Aoki, Kentaro; Goto, Tomotsugu; Imanishi, Masatoshi; Kawaguchi, Toshihiro; Terashima, Yuichi; Ueda, Yoshihiro; Bosch, James; Bundy, Kevin; Doi, Yoshiyuki; Inami, Hanae; Komiyama, Yutaka; Lupton, Robert H.; Matsuhara, Hideo; Matsuoka, Yoshiki; Miyazaki, Satoshi; Morokuma, Tomoki; Nakata, Fumiaki; Oi, Nagisa; Onoue, Masafusa; Oyabu, Shinki; Price, Paul; Tait, Philip J.; Takata, Tadafumi; Tanaka, Manobu M.; Terai, Tsuyoshi; Turner, Edwin L.; Uchida, Tomohisa; Usuda, Tomonori; Utsumi, Yousuke; Yamada, Yoshihiko; Wang, Shiang-Yu

    2015-10-01

    We present the photometric properties of a sample of infrared (IR) bright dust-obscured galaxies (DOGs). Combining wide and deep optical images obtained with the Hyper Suprime-Cam on the Subaru Telescope and all-sky mid-IR (MIR) images taken with Wide-Field Infrared Survey Explorer, we discovered 48 DOGs with i - Ks > 1.2 and i - [22] > 7.0, where i, Ks, and [22] represent AB magnitude in the i-band, Ks-band, and 22 μm, respectively, in the GAMA 14 hr field (˜ 9 deg2). Among these objects, 31 (˜ 65%) show power-law spectral energy distributions (SEDs) in the near-IR (NIR) and MIR regime, while the remainder show an NIR bump in their SEDs. Assuming that the redshift distribution for our DOGs sample is Gaussian, with mean and sigma z = 1.99 ± 0.45, we calculated their total IR luminosity using an empirical relation between 22 μm luminosity and total IR luminosity. The average value of the total IR luminosity is (3.5 ± 1.1) × 1013 L⊙, which classifies them as hyper-luminous infrared galaxies. We also derived the total IR luminosity function (LF) and IR luminosity density (LD) for a flux-limited subsample of 18 DOGs with 22 μm flux greater than 3.0 mJy and with i-band magnitude brighter than 24 AB magnitude. The derived space density for this subsample is log φ = -6.59 ± 0.11 [Mpc-3]. The IR LF for DOGs including data obtained from the literature is fitted well by a double-power law. The derived lower limit for the IR LD for our sample is ρIR ˜ 3.8 × 107 [L⊙ Mpc-3] and its contributions to the total IR LD, IR LD of all ultra-luminous infrared galaxies, and that of all DOGs are > 3%, > 9%, and > 15%, respectively.

  15. 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.

  16. Multiwavelength Energy Distributions and Bolometric Luminosities of the 12 Micron Galaxy Sample

    NASA Astrophysics Data System (ADS)

    Spinoglio, Luigi; Malkan, Matthew A.; Rush, Brian; Carrasco, Luis; Recillas-Cruz, Elsa

    1995-11-01

    Aperture photometry from our own observations and the literature is presented for the 12 microns galaxies in the near-infrared J, H, and K bands and, in some cases, in the L band. These data are corrected to "total" near-infrared magnitudes (with a typical uncertainty of 0.3 mag) for a direct comparison with our IRAS fluxes which apply to the entire galaxy. The corrected data are used to derive integrated total near-infrared and far-infrared luminosities. We then combine these with blue photometry and an estimate of the flux contribution from cold dust at wavelengths longward of 100 microns to derive the first bolometric luminosities for a large sample of galaxies. The presence of nonstellar radiation at 2-3 microns correlates very well with nonstellar IRAS colors. This enables us to identify a universal Seyfert nuclear continuum from near- to far-infrared wavelengths. Thus, there is a sequence of infrared colors which runs from a pure "normal galaxy" to a pure Seyfert/quasar nucleus. Seyfert 2 galaxies fall close to this same sequence, although only a few extreme narrow-line Seyfert galaxies have quasar-like colors, and these show strong evidence of harboring an obscured broad-line region. A corollary is that the host galaxies of Seyfert nuclei have normal near- to far-infrared spectra on average. Starburst galaxies lie significantly off the sequence, having a relative excess of 60 microns emission probably as a result of stochastically heated dust grains. We use these correlations to identify several combinations of infrared colors which discriminate between Seyfert 1 and 2 galaxies, LINERs, and ultraluminous starbursts. In the infrared, Seyfert 2 galaxies are much more like Seyfert 1s than they are like starbursts, presumably because both kinds of Seyferts are heated by a single central source, rather than a distributed region of star formation. Moreover, combining the [25-2.2 mum] color with the [60-12 mum] color, it appears that Seyfert 1 galaxies are

  17. 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.

  18. 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.

  19. Correlated X-ray/ultraviolet/optical variability and the nature of accretion disc in the bare Seyfert 1 galaxy Fairall 9

    NASA Astrophysics Data System (ADS)

    Pal, Main; Dewangan, Gulab C.; Connolly, S. D.; Misra, Ranjeev

    2017-04-01

    We study the multiwavelength variability of the bare Seyfert 1 galaxy Fairall 9 using Swift monitoring observations consisting of 165 usable pointings spanning nearly two years and covering six ultraviolet (UV)/optical bands and X-rays. Fairall 9 is highly variable in all bands though the variability amplitude decreases from X-ray to optical bands. The variations in the X-ray and UV/optical bands are strongly correlated. Our reverberation mapping analysis using the JAVALIN tool shows that the variation in the UV/optical bands lag behind the variations in the X-ray band by ∼2-10 d. These lag measurements strongly suggest that the optical/UV variations are mainly caused by variations in the X-rays, and the origin of most of the optical/UV emission is X-ray reprocessing. The observed lags are found to vary as τ ∝ λ1.36 ± 0.13, consistent with the prediction, τ ∝ λ4/3, for X-ray reprocessing in a standard accretion disc. However, the predicted lags for a standard accretion disc with X-ray reprocessing using the black hole mass (MBH ∼ 2.6 × 108 M⊙) estimated from the reverberation mapping of broad emission lines and the accretion rate relative to the Eddington rate (dot{m_E}=0.02) are shorter than the observed lags. These observations suggest that the accretion disc in Fairall 9 is larger than that predicted by the standard disc model, and confirm similar findings in a few other Seyfert 1 galaxies such as NGC 5548.

  20. Clustering of Infrared-bright Dust-obscured Galaxies Revealed by the Hyper Suprime-Cam and WISE

    NASA Astrophysics Data System (ADS)

    Toba, Yoshiki; Nagao, Tohru; Kajisawa, Masaru; Oogi, Taira; Akiyama, Masayuki; Ikeda, Hiroyuki; Coupon, Jean; Strauss, Michael A.; Wang, Wei-Hao; Tanaka, Masayuki; Niida, Mana; Imanishi, Masatoshi; Lee, Chien-Hsiu; Matsuhara, Hideo; Matsuoka, Yoshiki; Onoue, Masafusa; Terashima, Yuichi; Ueda, Yoshihiro; Harikane, Yuichi; Komiyama, Yutaka; Miyazaki, Satoshi; Noboriguchi, Akatoki; Usuda, Tomonori

    2017-01-01

    We present measurements of the clustering properties of a sample of infrared (IR) bright dust-obscured galaxies (DOGs). Combining 125 deg2 of wide and deep optical images obtained with the Hyper Suprime-Cam on the Subaru Telescope and all-sky mid-IR images taken with Wide-Field Infrared Survey Explorer, we have discovered 4367 IR-bright DOGs with {(i-[22])}{AB}> 7.0 and flux density at 22 μ {{m}}> 1.0 mJy. We calculate the angular autocorrelation function (ACF) for a uniform subsample of 1411 DOGs with 3.0 mJy < flux (22 μ {{m}}) < 5.0 mJy and {i}{AB} < 24.0. The ACF of our DOG subsample is well-fit with a single power law, ω (θ ) = (0.010 ± 0.003) {θ }-0.9, where θ is in degrees. The correlation amplitude of IR-bright DOGs is larger than that of IR-faint DOGs, which reflects a flux dependence of the DOG clustering, as suggested by Brodwin et al. We assume that the redshift distribution for our DOG sample is Gaussian, and consider two cases: (1) the redshift distribution is the same as IR-faint DOGs with flux at 22 μ {{m}} < 1.0 mJy, mean and sigma z = 1.99 ± 0.45, and (2) z = 1.19 ± 0.30, as inferred from their photometric redshifts. The inferred correlation length of IR-bright DOGs is r0 = 12.0 ± 2.0 and 10.3 ± 1.7 {h}-1 Mpc, respectively. IR-bright DOGs reside in massive dark matter halos with a mass of {log}[< {M}{{h}}> /({h}-1 {M}ȯ )]={13.57}-0.55+0.50 and {13.65}-0.52+0.45 in the two cases, respectively.

  1. Infrared Spectroscopy of a Massive Obscured Star Cluster in the Antennae Galaxies (NGC 4038/9) with NIRSPEC.

    PubMed

    Gilbert; Graham; McLean; Becklin; Figer; Larkin; Levenson; Teplitz; Wilcox

    2000-04-10

    We present infrared spectroscopy of the Antennae galaxies (NGC 4038/9) with the near-infrared spectrometer (NIRSPEC) at the W. M. Keck Observatory. We imaged the star clusters in the vicinity of the southern nucleus (NGC 4039) with 0&farcs;39 seeing in the K band using NIRSPEC's slit-viewing camera. The brightest star cluster revealed in the near-IR [MK&parl0;0&parr0; approximately -17.9] is insignificant optically but is coincident with the highest surface brightness peak in the mid-IR (12-18 µm) Infrared Space Observatory image presented by Mirabel et al. We obtained high signal-to-noise ratio 2.03-2.45 µm spectra of the nucleus and the obscured star cluster at R approximately 1900. The cluster is very young ( approximately 4 Myr), massive (M approximately 16x106 M middle dot in circle), and compact (with a density of approximately 115 M middle dot in circle pc-3 within a 32 pc half-light radius), assuming a Salpeter initial mass function (0.1-100 M middle dot in circle). Its hot stars have a radiation field characterized by Teff approximately 39,000 K, and they ionize a compact H ii region with ne approximately 104 cm-3. The stars are deeply embedded in gas and dust (AV approximately 9-10 mag), and their strong far-ultraviolet field powers a clumpy photodissociation region with densities nH greater, similar105 cm-3 on scales of approximately 200 pc, radiating LH21-0S&parl0;1&parr0;=9600 L middle dot in circle.

  2. ALMA observations of the host galaxy of GRB 090423 at z = 8.23: deep limits on obscured star formation 630 million years after the big bang

    SciTech Connect

    Berger, E.; Zauderer, B. A.; Chary, R.-R.; Laskar, T.; Chornock, R.; Davies, J. E.; Tanvir, N. R.; Stanway, E. R.; Levan, A. J.; Levesque, E. M.

    2014-12-01

    We present rest-frame far-infrared (FIR) and optical observations of the host galaxy of GRB 090423 at z = 8.23 from the Atacama Large Millimeter Array (ALMA) and the Spitzer Space Telescope, respectively. The host remains undetected to 3σ limits of F {sub ν}(222 GHz) ≲ 33 μJy and F {sub ν}(3.6 μm) ≲ 81 nJy. The FIR limit is about 20 times fainter than the luminosity of the local ULIRG Arp 220 and comparable to the local starburst M 82. Comparing this with model spectral energy distributions, we place a limit on the infrared (IR) luminosity of L {sub IR}(8-1000 μm) ≲ 3 × 10{sup 10} L {sub ☉}, corresponding to a limit on the obscured star formation rate of SFR{sub IR}≲5 M {sub ☉} yr{sup –1}. For comparison, the limit on the unobscured star formation rate from Hubble Space Telescope rest-frame ultraviolet (UV) observations is SFR{sub UV} ≲ 1 M {sub ☉} yr{sup –1}. We also place a limit on the host galaxy stellar mass of M {sub *} ≲ 5 × 10{sup 7} M {sub ☉} (for a stellar population age of 100 Myr and constant star formation rate). Finally, we compare our millimeter observations to those of field galaxies at z ≳ 4 (Lyman break galaxies, Lyα emitters, and submillimeter galaxies) and find that our limit on the FIR luminosity is the most constraining to date, although the field galaxies have much larger rest-frame UV/optical luminosities than the host of GRB 090423 by virtue of their selection techniques. We conclude that GRB host galaxies at z ≳ 4, especially those with measured interstellar medium metallicities from afterglow spectroscopy, are an attractive sample for future ALMA studies of high redshift obscured star formation.

  3. The Stellar Population and Emitting Gas in the Inner 2-5-KPC for a Sample of Nine SEYFERT-2 Galaxies

    NASA Astrophysics Data System (ADS)

    Storchi-Bergmann, T.; Bica, E.; Pastoriza, M. G.

    1990-08-01

    We analyse the stellar population and the emitting gas in the inner 2-5 kpc of a sample of nine Seyfert 2 galaxies, using 5-A resolution spectra in the range 3600-7000 A. The typical population is old and moderately strong-lined, except in IC 5135 which presents star-forming events. The emission-line spectrum is studied after subtraction of the stellar population. Broad Hα components (FWHM = 2000 km s^-1^) were found for five of the galaxies. The line widths correlate with the critical densities for the forbidden lines in four of the galaxies and with the ionization potential in three of these, indicating the presence of density stratification and ionization structure. Comparison of our emission-line ratios with smaller aperture data obtained from the literature reveal important changes in the values due to contamination by surrounding gas. Using photo-ionization models we derive gas abundances between solar and two-times solar, with an overabundance of nitrogen in NGC 4939 and 6890, and of nitrogen and sulphur in NGC 1667, relative to the other heavy elements.

  4. Evidence of bar-driven secular evolution in the gamma-ray narrow-line Seyfert 1 galaxy FBQS J164442.5+261913

    NASA Astrophysics Data System (ADS)

    Olguín-Iglesias, A.; Kotilainen, J. K.; León Tavares, J.; Chavushyan, V.; Añorve, C.

    2017-01-01

    We present near-infrared (NIR) imaging of FBQS J164442.5+261913, one of the few γ-ray emitting Narrow Line Seyfert 1 (NLSy1) galaxies detected at high significance level by Fermi-LAT. This study is the first morphological analysis performed of this source and the third performed of this class of objects. Conducting a detailed two-dimensional modeling of its surface brightness distribution and analysing its J - Ks colour gradients, we find that FBQS J164442.5+261913 is statistically most likely hosted by a barred lenticular galaxy (SB0). We find evidence that the bulge in the host galaxy of FBQS J164442.5+261913 is not classical but pseudo, against the paradigm of powerful relativistic jets exclusively launched by giant ellipticals. Our analysis, also reveal the presence of a ring with diameter equalling the bar length (rbar = 8.13 kpc ± 0.25), whose origin might be a combination of bar-driven gas rearrangement and minor mergers, as revealed by the apparent merger remnant in the J-band image. In general, our results suggest that the prominent bar in the host galaxy of FBQS J164442.5+261913 has mostly contributed to its overall morphology driving a strong secular evolution, which plays a crucial role in the onset of the nuclear activity and the growth of the massive bulge. Minor mergers, in conjunction, are likely to provide the necessary fresh supply of gas to the central regions of the host galaxy.

  5. 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.

  6. Delving into X-Ray Obscuration of Type 2 AGN, Near and Far

    NASA Technical Reports Server (NTRS)

    Lamassa, Stephanie M.; Yaqoob, Tahir; Ptak, Andrew F.; Jia, Jianjun; Heckman, Timothy M.; Gandhi, Poshak; Urry, C. Meg

    2014-01-01

    Using self-consistent, physically motivated models, we investigate the X-ray obscuration in 19 Type 2 [O iii] 5007Å selected active galactic nuclei (AGNs), 9 of which are local Seyfert 2 galaxies and 10 of which are Type 2 quasar candidates. We derive reliable line-of-sight and global column densities for these objects, which is the first time this has been reported for an AGN sample; four AGNs have significantly different global and line-of-sight column densities. Five sources are heavily obscured to Compton-thick. We comment on interesting sources revealed by our spectral modeling, including a candidate "naked" Sy2. After correcting for absorption, we find that the ratio of the rest-frame, 2-10 keV luminosity (L2-10 keV,in) to L[O iii] is 1.54 +/- 0.49 dex which is essentially identical to the mean Type 1 AGN value. The Fe K(alpha) luminosity is significantly correlated with L[O iii] but with substantial scatter. Finally, we do not find a trend between L2-10 keV,in and global or line-of-sight column density, between column density and redshift, between column density and scattering fraction, or between scattering fraction and redshift. Key words: galaxies: active - galaxies: Seyfert - X-rays: general

  7. Integral Field Spectroscopy of Markarian 273: Mapping High-Velocity Gas Flows and an Off-Nucleus Seyfert 2 Nebula.

    PubMed

    Colina; Arribas; Borne

    1999-12-10

    Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies.

  8. 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.

  9. Discovery of Dramatic Optical Variability in SDSS J1100+4421: A Peculiar Radio-loud Narrow-line Seyfert 1 Galaxy?

    NASA Astrophysics Data System (ADS)

    Tanaka, Masaomi; Morokuma, Tomoki; Itoh, Ryosuke; Akitaya, Hiroshi; Tominaga, Nozomu; Saito, Yoshihiko; Stawarz, Łukasz; Tanaka, Yasuyuki T.; Gandhi, Poshak; Ali, Gamal; Aoki, Tsutomu; Contreras, Carlos; Doi, Mamoru; Essam, Ahmad; Hamed, Gamal; Hsiao, Eric Y.; Iwata, Ikuru; Kawabata, Koji S.; Kawai, Nobuyuki; Kikuchi, Yuki; Kobayashi, Naoto; Kuroda, Daisuke; Maehara, Hiroyuki; Matsumoto, Emiko; Mazzali, Paolo A.; Minezaki, Takeo; Mito, Hiroyuki; Miyata, Takashi; Miyazaki, Satoshi; Mori, Kensho; Moritani, Yuki; Morokuma-Matsui, Kana; Morrell, Nidia; Nagao, Tohru; Nakada, Yoshikazu; Nakata, Fumiaki; Noma, Chinami; Ohsuga, Ken; Okada, Norio; Phillips, Mark M.; Pian, Elena; Richmond, Michael W.; Sahu, Devendra; Sako, Shigeyuki; Sarugaku, Yuki; Shibata, Takumi; Soyano, Takao; Stritzinger, Maximilian D.; Tachibana, Yutaro; Taddia, Francesco; Takaki, Katsutoshi; Takey, Ali; Tarusawa, Ken'ichi; Ui, Takahiro; Ukita, Nobuharu; Urata, Yuji; Walker, Emma S.; Yoshii, Taketoshi

    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 ~107 M ⊙ 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 × 102-3 × 103, 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.

  10. 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.

  11. Black hole growth and starburst activity at z = 0.6-4 in the Chandra Deep Field South. Host galaxies properties of obscured AGN

    NASA Astrophysics Data System (ADS)

    Brusa, M.; Fiore, F.; Santini, P.; Grazian, A.; Comastri, A.; Zamorani, G.; Hasinger, G.; Merloni, A.; Civano, F.; Fontana, A.; Mainieri, V.

    2009-12-01

    Aims: The co-evolution of host galaxies and the active black holes which reside in their centre is one of the most important topics in modern observational cosmology. Here we present a study of the properties of obscured active galactic nuclei (AGN) detected in the CDFS 1 Ms observation and their host galaxies. Methods: We limited the analysis to the MUSIC area, for which deep K-band observations obtained with ISAAC@VLT are available, ensuring accurate identifications of the counterparts of the X-ray sources as well as reliable determination of photometric redshifts and galaxy parameters, such as stellar masses and star formation rates. In particular, we: 1) refined the X-ray/infrared/optical association of 179 sources in the MUSIC area detected in the Chandra observation; 2) studied the host galaxies observed and rest frame colors and properties. Results: We found that X-ray selected (LX ⪆ 1042 erg s-1) AGN show Spitzer colors consistent with both AGN and starburst dominated infrared continuum; the latter would not have been selected as AGN from infrared diagnostics. The host galaxies of X-ray selected obscured AGN are all massive (Mast > 1010 M_⊙) and, in 50% of the cases, are also actively forming stars (1/SSFR < tHubble) in dusty environments. The median L/LEdd value of the active nucleus is between 2% and 10% depending on the assumed MBH/Mast ratio. Finally, we found that the X-ray selected AGN fraction increases with the stellar mass up to a value of 30% at z > 1 and Mast > 3 × 1011 M_⊙, a fraction significantly higher than in the local Universe for AGN of similar luminosities. Tables [see full textsee full textsee full text] and [see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

  12. Incidence of WISE-Selected Obscured AGNs in Major Mergers and Interactions from the SDSS

    NASA Astrophysics Data System (ADS)

    Weston, Madalyn; McIntosh, Daniel H.; Brodwin, Mark; Mann, Justin; Cooper, Andrew; McConnell, Adam; Nielson, Jennifer L.

    2017-01-01

    We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z≤0.08) catalog of visually-selected major mergers and galaxy-galaxy interactions from the SDSS, with stellar masses above 2×10^10 M⊙, we find that major mergers (interactions) are 5--17 (3--5) times more likely to have red [3.4]-[4.6] colors associated with dust-obscured or `dusty' AGNs, compared to non-merging galaxies with similar masses. Using published fiber spectral diagnostics, we map the [3.4]-[4.6] versus [4.6]-[12] colors of different emission-line galaxies and find one-quarter of Seyferts have colors indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGNs missed at shorter wavelengths are at the heart of the ongoing AGN-merger connection debate. The vast majority of mergers hosting dusty AGNs are star-forming and located at the centers of Mhalo<10^13 M⊙ groups. Assuming plausibly short duration dusty-AGN phases, we speculate that a large fraction of gas-rich mergers experience a brief obscured AGN phase, in agreement with the strong connection between central star formation and black hole growth seen in merger simulations. We will use the WISE-selected AGNs (and AGNs selected by other methods) to perform SED analysis of mergers and interactions and dissect the SEDs to disentangle AGN and SF activity.

  13. Incidence of WISE -selected obscured AGNs in major mergers and interactions from the SDSS

    NASA Astrophysics Data System (ADS)

    Weston, Madalyn E.; McIntosh, Daniel H.; Brodwin, Mark; Mann, Justin; Cooper, Andrew; McConnell, Adam; Nielsen, Jennifer L.

    2017-02-01

    We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z ≤ 0.08) catalogue of visually selected major mergers and galaxy-galaxy interactions from the SDSS, with stellar masses above 2 × 1010 M⊙, we find that major mergers (interactions) are 5-17 (3-5) times more likely to have red [3.4] - [4.6] colours associated with dust-obscured or `dusty' AGNs, compared to non-merging galaxies with similar masses. Using published fibre spectral diagnostics, we map the [3.4] - [4.6] versus [4.6] - [12] colours of different emission-line galaxies and find that one-quarter of Seyferts have colours indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGNs missed at shorter wavelengths are at the heart of the ongoing AGN-merger connection debate. The vast majority of mergers hosting dusty AGNs are star forming and located at the centres of Mhalo < 1013 M⊙ groups. Assuming plausibly short-duration dusty-AGN phases, we speculate that a large fraction of gas-rich mergers experience a brief obscured AGN phase, in agreement with the strong connection between central star formation and black hole growth seen in merger simulations.

  14. 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.

  15. 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.

  16. 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.

  17. Simultaneous NuSTAR and XMM-Newton 0.5-80 keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654

    NASA Astrophysics Data System (ADS)

    Marinucci, A.; Matt, G.; Kara, E.; Miniutti, G.; Elvis, M.; Arevalo, P.; Ballantyne, D. R.; Baloković, 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.

    2014-05-01

    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 ks performed during three XMM-Newton orbits. We detect a relativistic broadened iron Kα 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^{+0.11}_{-0.17}. The intrinsic spectrum is steep (Γ = 2.08 ± 0.01) as commonly found in narrow-line Seyfert 1 galaxies, while the cutoff energy (E_c=108^{+11}_{-10} keV) 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 rg. These timing results independently support an intermediate black hole spin and a compact corona.

  18. 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).

  19. Inner jet kinematics and the viewing angle towards the γ-ray narrow-line Seyfert 1 galaxy 1H 0323+342

    NASA Astrophysics Data System (ADS)

    Fuhrmann, Lars; Karamanavis, Vassilis; Komossa, Stefanie; Angelakis, Emmanouil; Krichbaum, Thomas P.; Schulz, Robert; Kreikenbohm, Annika; Kadler, Matthias; Myserlis, Ioannis; Ros, Eduardo; Nestoras, Ioannis; Zensus, J. Anton

    2016-11-01

    Near-Eddington accretion rates onto low-mass black holes are thought to be a prime driver of the multi-wavelength properties of the narrow-line Seyfert 1 (NLS1) population of active galactic nuclei (AGNs). Orientation effects have repeatedly been considered as another important factor involved, but detailed studies have been hampered by the lack of measured viewing angles towards this type of AGN. Here we present multi-epoch, 15 GHz VLBA images (MOJAVE program) of the radio-loud and Fermi/LAT-detected NLS1 galaxy 1H 0323+342. These are combined with single-dish, multi-frequency radio monitoring of the source's variability, obtained with the Effelsberg 100-m and IRAM 30-m telescopes, in the course of the F-GAMMA program. The VLBA images reveal six components with apparent speeds of ˜ 1-7 c, and one quasi-stationary feature. Combining the obtained apparent jet speed (β app) and variability Doppler factor (D var) estimates together with other methods, we constrain the viewing angle θ towards 1H 0323+342 to θ ≤ 4°-13°. Using literature values of βapp and D var, we also deduce a viewing angle of ≤ 8°-9° towards another radio- and γ-ray-loud NLS1, namely SBS 0846+513.

  20. Evidence for Relativistic Disk Reflection in the Seyfert 1h Galaxy/ULIRG IRAS 05189–2524 Observed by NuSTAR and XMM-Newton

    NASA Astrophysics Data System (ADS)

    Xu, Yanjun; Baloković, Mislav; Walton, Dominic J.; Harrison, Fiona A.; García, Javier A.; Koss, Michael J.

    2017-03-01

    We present a spectral analysis of the NuSTAR and XMM-Newton observations of the Seyfert 1h galaxy/ULIRG IRAS 05189–2524 taken in 2013. We find evidence for relativistic disk reflection in the broadband X-ray spectrum: a highly asymmetric broad Fe Kα emission line extending down to 3 keV and a Compton scattering component above 10 keV. Physical modeling with a self-consistent disk reflection model suggests that the accretion disk is viewed at an intermediate angle with a supersolar iron abundance, and a mild constraint can be put on the high-energy cutoff of the power-law continuum. We test the disk reflection modeling under different absorption scenarios. A rapid black hole spin is favored; however, we cannot place a model-independent tight constraint on the value. The high reflection fraction ({R}{ref} ≃ 2.0–3.2) suggests that the coronal illuminating source is compact and close to the black hole (lying within 8.7 {R}{{g}} above the central black hole), where light-bending effects are important.

  1. 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.

  2. MINUTE-SCALE RAPID VARIABILITY OF THE OPTICAL POLARIZATION IN THE NARROW-LINE SEYFERT 1 GALAXY PMN J0948+0022

    SciTech Connect

    Itoh, Ryosuke; Tanaka, Yasuyuki T.; Fukazawa, Yasushi; Kawaguchi, Kenji; Takaki, Katsutoshi; Ueno, Issei; Kawabata, Koji S.; Moritani, Yuki; Uemura, Makoto; Akitaya, Hiroshi; Yoshida, Michitoshi; Ohsugi, Takashi; Hanayama, Hidekazu; Miyaji, Takeshi; Kawai, Nobuyuki

    2013-09-20

    We report on optical photopolarimetric results of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy PMN J0948+0022 on 2012 December to 2013 February triggered by flux enhancements in the near infrared and γ-ray bands. With the one-shot polarimetry of the Hiroshima One-shot Wide field Polarimeter installed on the Kanata Telescope, we detected very rapid variability in the polarized-flux (PF) light curve on MJD 56281 (2012 December 20). The rise and decay times were about 140 s and 180 s, respectively. The polarization degree (PD) reached 36% ± 3% at the peak of the short-duration pulse, while the polarization angle remained almost constant. In addition, temporal profiles of the total flux and PD showed highly variable but well correlated behavior and discrete correlation function analysis revealed that no significant time lag of more than 10 minutes was present. The high PD and minute-scale variability in PF provides clear evidence of synchrotron radiation from a very compact emission region of ∼10{sup 14} cm size with a highly ordered magnetic field. Such micro-variability of polarization is also observed in several blazar jets, but its complex relation between total flux and PD are explained by a multi-zone model in several blazars. The implied single emission region in PMN J0948+0022 might reflect a difference of jets between RL-NLSy1s and blazars.

  3. On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342

    NASA Astrophysics Data System (ADS)

    Landt, H.; Ward, M. J.; Baloković, M.; Kynoch, D.; Storchi-Bergmann, T.; Boisson, C.; Done, C.; Schimoia, J.; Stern, D.

    2017-01-01

    Narrow-line Seyfert 1 galaxies have been identified by the Fermi Gamma-Ray Space Telescope as a rare class of γ-ray emitting active galactic nuclei. The lowest redshift candidate among them is the source 1H 0323+342. Here we present quasi-simultaneous Gemini near-infrared and Keck optical spectroscopy for it, from which we derive a black hole mass based on both the broad Balmer and Paschen emission lines. We supplement these observations with a Nuclear Spectroscopic Telescope Array X-ray spectrum taken about two years earlier, from which we constrain the black hole mass based on the short time-scale spectral variability. Our multiwavelength observations suggest a black hole mass of ˜2 × 107 M⊙, which agrees well with previous estimates. We build the spectral energy distribution and show that it is dominated by the thermal and reprocessed emission from the accretion disc rather than the non-thermal jet component. A detailed spectral fitting with the energy-conserving accretion disc model of Done et al. constrains the Eddington ratio to L/LEdd ˜ 0.5 for a (non-rotating) Schwarzschild black hole and to L/LEdd ˜ 1 for a Kerr black hole with dimensionless spin of a⋆ = 0.8. Higher spin values and so higher Eddington ratios are excluded, since they would strongly overpredict the observed soft X-ray flux.

  4. The Chandra High Energy Transmission Grating Spectrometer probes the dusty warm absorber in the Seyfert 1 galaxy MCG-6-30-15

    NASA Astrophysics Data System (ADS)

    Lee, J. C.; Canizares, C. R.; Marshall, H. L.; Morales, R.; Schulz, N. S.; Iwasawa, K.

    The Chandra HETGS spectra of the Seyfert 1 galaxy MCG-6-30-15 show numerous narrow, unresolved (FWHM ≈< 200 km s-1) absorption lines from a wide range of ionization states of N, O, Mg, Ne, Si, S, Ar, and Fe. The initial analysis of these data, presented in Lee et al. (2001), shows that a dusty warm absorber model adequately explains the spectral features ≈> 0.48 keV (≈< 26 Å ). We attribute previous reports of an apparently highly redshifted O VII edge to the neutral Fe L absorption complex and the O VII resonance series (by transitions higher than He γ He α,β,γ are also seen at lower energies). The implied dust column density needed to explain the Fe I L edge feature agrees with that obtained from earlier reddening studies, which had already concluded that the dust should be associated with the ionized absorber (given the relatively lower observed X-ray absorption by cold gas). Our findings contradict the interpretation of Branduardi-Raymont et al. (2001), based on XMM RGS spectra, that this spectral region is dominated by highly relativistic soft X-ray line emission originating near the central black hole. Here we review these issues pertaining to the soft X-ray spectral features as addressed by Lee et al., (2001). Details found in Lee et al., 2001, ApJ., 554, L13

  5. Minute-scale Rapid Variability of the Optical Polarization in the Narrow-line Seyfert 1 Galaxy PMN J0948+0022

    NASA Astrophysics Data System (ADS)

    Itoh, Ryosuke; Tanaka, Yasuyuki T.; Fukazawa, Yasushi; Kawabata, Koji S.; Kawaguchi, Kenji; Moritani, Yuki; Takaki, Katsutoshi; Ueno, Issei; Uemura, Makoto; Akitaya, Hiroshi; Yoshida, Michitoshi; Ohsugi, Takashi; Hanayama, Hidekazu; Miyaji, Takeshi; Kawai, Nobuyuki

    2013-09-01

    We report on optical photopolarimetric results of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy PMN J0948+0022 on 2012 December to 2013 February triggered by flux enhancements in the near infrared and γ-ray bands. With the one-shot polarimetry of the Hiroshima One-shot Wide field Polarimeter installed on the Kanata Telescope, we detected very rapid variability in the polarized-flux (PF) light curve on MJD 56281 (2012 December 20). The rise and decay times were about 140 s and 180 s, respectively. The polarization degree (PD) reached 36% ± 3% at the peak of the short-duration pulse, while the polarization angle remained almost constant. In addition, temporal profiles of the total flux and PD showed highly variable but well correlated behavior and discrete correlation function analysis revealed that no significant time lag of more than 10 minutes was present. The high PD and minute-scale variability in PF provides clear evidence of synchrotron radiation from a very compact emission region of ~1014 cm size with a highly ordered magnetic field. Such micro-variability of polarization is also observed in several blazar jets, but its complex relation between total flux and PD are explained by a multi-zone model in several blazars. The implied single emission region in PMN J0948+0022 might reflect a difference of jets between RL-NLSy1s and blazars.

  6. The Seyfert 2 galaxy NGC 2110: hard X-ray emission observed by NuSTAR and variability of the iron Kα line

    NASA Astrophysics Data System (ADS)

    Marinucci, A.; Matt, G.; Bianchi, S.; Lu, T. N.; Arevalo, P.; Baloković, M.; Ballantyne, D.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Gandhi, P.; Hailey, C. J.; Harrison, F.; Puccetti, S.; Rivers, E.; Walton, D. J.; Stern, D.; Zhang, W.

    2015-02-01

    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 Ec > 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 Kα line on time-scales of years. The Fe Kα 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).

  7. Similarity of jet radiation between flat spectrum radio quasars and GeV narrow-line Seyfert 1 galaxies: a universal δ-L c correlation

    NASA Astrophysics Data System (ADS)

    Zhu, Yong-Kai; Zhang, Jin; Zhang, Hai-Ming; Liang, En-Wei; Yan, Da-Hai; Cui, Wei; Zhang, Shuang-Nan

    2016-11-01

    By modeling the broadband spectral energy distributions (SEDs) of a typical flat spectrum radio quasar (FSRQ, 3C 279) and two GeV narrow-line Seyfert 1 galaxies (NLS1s, PMN J0948+0022 and 1H 0323+342) in different flux stages with one-zone leptonic models, we find a universal correlation between their Doppler factors (δ) and peak luminosities (L c) of external Compton scattering bumps. Compiling a combined sample of FSRQs and GeV NLS1s, it is found that both FSRQs and GeV NLS1s in different stages and in different sources follow the same δ-L c correlation well. This indicates that the variations of observed luminosities may be essentially due to the Doppler boosting effect. The universal δ-L c relation between FSRQs and GeV NLS1s in different stages may be further evidence that the particle acceleration and radiation mechanisms for the two kinds of sources are similar. In addition, by replacing L c with the observed luminosity in the Fermi/LAT band (L LAT), this correlation holds and it may serve as an empirical indicator of δ. We estimate the δ values with L LAT for 484 FSRQs in the Fermi/LAT Catalog and they range from 3 to 41, with a median of 16, which are statistically consistent with the values derived by other methods.

  8. SDSS J143244.91+301435.3: a link between radio-loud narrow-line Seyfert 1 galaxies and compact steep-spectrum radio sources?

    NASA Astrophysics Data System (ADS)

    Caccianiga, A.; Antón, S.; Ballo, L.; Dallacasa, D.; Della Ceca, R.; Fanali, R.; Foschini, L.; Hamilton, T.; Kraus, A.; Maccacaro, T.; Mack, K.-H.; Marchã, M. J.; Paulino-Afonso, A.; Sani, E.; Severgnini, P.

    2014-06-01

    We present SDSS J143244.91+301435.3, a new case of a radio-loud narrow-line Seyfert 1 (RL NLS1) with a relatively high radio power (P1.4 GHz = 2.1 × 1025 W Hz-1) and large radio-loudness parameter (R1.4 = 600 ± 100). The radio source is compact with a linear size below ˜1.4 kpc but, in contrast to most of the RL NLS1 discovered so far with such a high R1.4, its radio spectrum is very steep (α = 0.93, Sν ∝ ν-α) and does not support a `blazar-like' nature. Both the small mass of the central supermassive black hole and the high accretion rate relative to the Eddington limit estimated for this object (3.2 × 107 M⊙ and 0.27, respectively, with a formal error of ˜0.4 dex for both quantities) are typical of the NLS1 class. Through modelling the spectral energy distribution of the source, we have found that the galaxy hosting SDSS J143244.91+301435.3 is undergoing quite intense star formation (SFR = 50 M⊙ yr-1), which, however, is expected to contribute only marginally (˜1 per cent) to the observed radio emission. The radio properties of SDSS J143244.91+301435.3 are remarkably similar to those of compact steep-spectrum (CSS) radio sources, a class of active galactic nuclei (AGN) mostly composed of young radio galaxies. This may suggest a direct link between these two classes of AGN, with CSS sources possibly representing the misaligned version (the so-called `parent population') of RL NLS1 showing blazar characteristics.

  9. 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.

  10. The Kiloparsec-scale Star Formation Law at Redshift 4: Widespread, Highly Efficient Star Formation in the Dust-obscured Starburst Galaxy GN20

    NASA Astrophysics Data System (ADS)

    Hodge, J. A.; Riechers, D.; Decarli, R.; Walter, F.; Carilli, C. L.; Daddi, E.; Dannerbauer, H.

    2015-01-01

    We present high-resolution observations of the 880 μm (rest-frame FIR) continuum emission in the z = 4.05 submillimeter galaxy GN20 from the IRAM Plateau de Bure Interferometer (PdBI). These data resolve the obscured star formation (SF) in this unlensed galaxy on scales of 0.''3 × 0.''2 (~2.1 × 1.3 kpc). The observations reveal a bright (16 ± 1 mJy) dusty starburst centered on the cold molecular gas reservoir and showing a bar-like extension along the major axis. The striking anti-correlation with the Hubble Space Telescope/Wide Field Camera 3 imaging suggests that the copious dust surrounding the starburst heavily obscures the rest-frame UV/optical emission. A comparison with 1.2 mm PdBI continuum data reveals no evidence for variations in the dust properties across the source within the uncertainties, consistent with extended SF, and the peak star formation rate surface density (119 ± 8 M ⊙ yr-1 kpc-2) implies that the SF in GN20 remains sub-Eddington on scales down to 3 kpc2. We find that the SF efficiency (SFE) is highest in the central regions of GN20, leading to a resolved SF law with a power-law slope of ΣSFR ~ Σ _H_2^2.1+/- 1.0, and that GN20 lies above the sequence of normal star-forming disks, implying that the dispersion in the SF law is not due solely to morphology or choice of conversion factor. These data extend previous evidence for a fixed SFE per free-fall time to include the star-forming medium on ~kiloparsec scales in a galaxy 12 Gyr ago. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  11. Powerful Radio Galaxies with Simbol-X: the Nuclear Environment

    NASA Astrophysics Data System (ADS)

    Torresi, E.; Grandi, P.; Malaguti, G.; Palumbo, G. G. C.; Bianchin, V.

    2009-05-01

    Fanaroff & Riley type II radio galaxies (FRII) are complex objects. In particular FRII Narrow Line Radio Galaxies (NLRG), optically classified as High Excitation Galaxies (HEG) show X-ray spectra very similar to their radio-quiet counterparts, the Seyfert 2 galaxies. They show 2-10 keV continua heavily obscured (NH~1023-24 cm-2) and intense FeKα lines, typical cold matter reprocessing features. Moreover recent Chandra and XMM-Newton observations suggest that the soft X-ray emission of HEG and Seyfert 2 have a common origin from photoionized gas, reinforcing the idea that not only their nuclear engine but also the circumnuclear gas (at least the warm phase) are similar. On the contrary, our knowledge of NLRG HEG above 10 keV is very poor when compared to brighter Seyfert 2. As a consequence, the physical properties of the cold phase of the circumnuclear gas (possibly linked to a dusty torus) are largely unknown. Thanks to its high sensitivity up to 80 keV, Simbol-X will provide very accurate spectra and will allow a direct comparison between the NLRG and Seyfert 2 cold environments.

  12. 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.

  13. 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.

  14. The awakening of the γ-ray narrow-line Seyfert 1 galaxy PKS 1502+036

    NASA Astrophysics Data System (ADS)

    D'Ammando, F.; Orienti, M.; Finke, J.; Hovatta, T.; Giroletti, M.; Max-Moerbeck, W.; Pearson, T. J.; Readhead, A. C. S.; Reeves, R. A.; Richards, J. L.

    2016-12-01

    After a long low-activity period, a γ-ray flare from the narrow-line Seyfert 1 PKS 1502+036 (z = 0.4089) was detected by the Large Area Telescope (LAT) on board Fermi in 2015. On 2015 December 20, the source reached a daily peak flux, in the 0.1-300 GeV band, of (93 ± 19) × 10-8 ph cm-2 s-1, attaining a flux of (237 ± 71) × 10-8 ph cm-2 s-1 on 3-h time-scales, which corresponds to an isotropic luminosity of (7.3 ± 2.1) × 1047 erg s-1. The γ-ray flare was not accompanied by significant spectral changes. We report on multiwavelength radio-to-γ-ray observations of PKS 1502+036 during 2008 August-2016 March by Fermi-LAT, Swift, XMM-Newton, Catalina Real-Time Transient Survey and the Owens Valley Radio Observatory (OVRO). An increase in activity was observed on 2015 December 22 by Swift in optical, UV and X-rays. The OVRO 15 GHz light curve reached the highest flux density observed from this source on 2016 January 12, indicating a delay of about three weeks between the γ-ray and 15 GHz emission peaks. This suggests that the γ-ray-emitting region is located beyond the broad-line region. We compared the spectral energy distribution (SED) of an average activity state with that of the flaring state. The two SED, with the high-energy bump modelled as an external Compton component with seed photons from a dust torus, could be fitted by changing the electron distribution parameters as well as the magnetic field. The fit of the disc emission during the average state constrains the black hole mass to values lower than 108 M⊙. The SED, high-energy emission mechanisms and γ-ray properties of the source resemble those of a flat spectrum radio quasar.

  15. Discovery of an Obscured Broad-Line Region in the High-Redshift Radio Galaxy MRC 2025-218.

    PubMed

    Larkin; McLean; Graham; Becklin; Figer; Gilbert; Levenson; Teplitz; Wilcox; Glassman

    2000-04-10

    This Letter presents infrared spectra taken with the newly commissioned near-infrared spectrometer (NIRSPEC) on the Keck II telescope of the high-redshift radio galaxy MRC 2025-218 (z=2.63). These observations represent the deepest infrared spectra of a radio galaxy to date and have allowed for the detection of Hbeta, [O iii] lambdalambda4959, 5007, [O i] lambda6300, Halpha, [N ii] lambdalambda6548, 6583, and [S ii] lambdalambda6716, 6713. The Halpha emission is very broad (FWHM=9300 km s-1) and luminous (2.6x1044 ergs s-1), and it is very comparable to the line widths and strengths of radio-loud quasars at the same redshift. This strongly supports active galactic nucleus unification models linking radio galaxies and quasars, although we discuss some of the outstanding differences. The line [O iii] lambda5007 is extremely strong and has extended emission with large relative velocities toward the nucleus. We also derive that if the extended emission is due to star formation, each knot has a star formation rate comparable to a Lyman-break galaxy at the same redshift.

  16. 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.

  17. 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.

  18. On the reality of broad iron L lines from the narrow line Seyfert 1 galaxies 1H0707-495 and IRAS 13224-3809

    NASA Astrophysics Data System (ADS)

    Karbhari Pawar, Pramod; Dewangan, Gulab Chand; Khushalrao Patil, Madhav; Misra, Ranjeev; Keshav Jogadand, Sharada

    2016-11-01

    We performed time resolved spectroscopy of 1H0707-495 and IRAS 13224-3809 using long XMM-Newton observations. These are strongly variable narrow line Seyfert 1 galaxies and show broad features around 1 keV that have been interpreted as relativistically broad Fe Lα lines. Such features are not clearly observed in other active galactic nuclei despite sometimes having high iron abundance required by the best fitted blurred reflection models. Given the importance of these lines, we explore whether the rapid variability of spectral parameters may introduce broad bumps/dips artificially in the time averaged spectrum, which may then be mistaken as broadened lines. We tested this hypothesis by performing time resolved spectroscopy using long (>100 ks) XMM-Newton observations and by dividing them into segments with typical exposures of a few ks. We extracted spectra from each such segment and modeled them using a two component phenomenological model consisting of a power law to represent the hard component and a black body to represent the soft emission. As expected, both the sources showed variations in the spectral parameters. Using these variation trends, we simulated model spectra for each segment and then co-added to get a combined simulated spectrum. In the simulated spectra, we found no broad features below 1 keV and in particular no deviation near 0.9 keV as seen in the real averaged spectra. This implies that the broad Fe Lα line that is seen in the spectra of these sources is not an artifact of the variation of spectral components and, hence, provides evidence that the line is indeed genuine.

  19. Short-term Radio Variability and Parsec-scale Structure in a Gamma-Ray Narrow-line Seyfert 1 Galaxy 1H 0323+342

    NASA Astrophysics Data System (ADS)

    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 × 1011 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) × 1010 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 1024.6 W Hz-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.

  20. High-resolution X-Ray Spectroscopy of the Seyfert 1 Galaxy Mrk 1040. Revealing the Failed Nuclear Wind with Chandra

    NASA Astrophysics Data System (ADS)

    Reeves, J. N.; Braito, V.; Behar, E.; Fischer, T. C.; Kraemer, S. B.; Lobban, A.; Nardini, E.; Porquet, D.; Turner, T. J.

    2017-03-01

    High-resolution X-ray spectroscopy of the warm absorber in the nearby X-ray bright Seyfert 1 galaxy Mrk 1040 is presented. The observations were carried out in the 2013–2014 timeframe using the Chandra High Energy Transmission Grating with a total exposure of 200 ks. A multitude of absorption lines from Ne, Mg, and Si are detected from a wide variety of ionization states. In particular, the detection of inner K-shell absorption lines from Ne, Mg, and Si, from charge states ranging from F-like to Li-like ions, suggests the presence of a substantial amount of low-ionization absorbing gas, illuminated by a steep soft X-ray continuum. The observations reveal at least three warm absorbing components ranging in ionization parameter from {log}(ξ /{erg} {cm} {{{s}}}-1)=0{--}2 and with column densities of {N}{{H}}=1.5{--}4.0× {10}21 cm‑2. The velocity profiles imply that the outflow velocities of the absorbing gas are low and within ±100 km s‑1 of the systemic velocity of Mrk 1040, which suggests that any outflowing gas may have stalled in this AGN on large enough scales. The warm absorber is likely located far from the black hole, within 300 pc of the nucleus, and is spatially coincident with emission from an extended narrow-line region as seen in the Hubble Space Telescope images. The iron K-band spectrum reveals only narrow emission lines, with Fe Kα at 6.4 keV consistent with originating from reflection off Compton-thick pc-scale reprocessing gas.

  1. 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.

  2. Coronal Properties of the Seyfert 1.9 Galaxy MCG-05-23-016 Determined from Hard X-Ray Spectroscopy with NuSTAR

    NASA Astrophysics Data System (ADS)

    Baloković, M.; Matt, G.; Harrison, F. A.; Zoghbi, A.; Ballantyne, D. R.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Esmerian, C. J.; Fabian, A. C.; Fürst, F.; Hailey, C. J.; Marinucci, A.; Parker, M. L.; Reynolds, C. S.; Stern, D.; Walton, D. J.; Zhang, W. W.

    2015-02-01

    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 116-5+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 kTe = 29 ± 2 keV and τ e = 1.23 ± 0.08 assuming a slab (disk-like) geometry, and kTe = 25 ± 2 keV and τ 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 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.

  3. 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.

  4. 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.

  5. 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

  6. Galaxy-wide outflows in z ~ 1.5 luminous obscured quasars revealed through near-IR slit-resolved spectroscopy

    NASA Astrophysics Data System (ADS)

    Perna, M.; Brusa, M.; Cresci, G.; Comastri, A.; Lanzuisi, G.; Lusso, E.; Marconi, A.; Salvato, M.; Zamorani, G.; Bongiorno, A.; Mainieri, V.; Maiolino, R.; Mignoli, M.

    2015-02-01

    Aims: The co-evolution of galaxies and supermassive black holes (SMBHs) requires that some sort of feedback mechanism is operating during the active galactic nuclei (AGN) phases. AGN driven winds are the most likely candidates for such feedback mechanism, but direct observational evidence of their existence and of their effects on the host galaxies are still scarce and their physical origin is still hotly debated. Methods: X-Shooter observations of a sample of X-ray selected, obscured quasars at z ~ 1.5, selected on the basis of their observed red colors and X-ray-to-optical flux ratio, have shown the presence of outflowing ionized gas identified by broad [OIII] emission lines in 6 out of 8 objects, confirming the efficiency of the selection criteria. Here we present slit-resolved spectroscopy for the two brightest sources, XID2028 and XID5321, to study the complex emission and absorption line kinematics. Results: We detect outflow extended out to ~10 kpc from the central black hole, both as blueshifted and redshifted emission. Interestingly, we also detect kpc scale outflows in the [OII] emission lines and in the neutral gas component, traced by the sodium D and magnesium absorption lines, confirming that a substantial amount of the outflowing mass is in the form of neutral gas. Conclusions: The measured gas velocities and the outflow kinetic powers, inferred under reasonable assumptions on the geometry and physical properties of these two systems, favor an AGN origin for the observed winds.

  7. THE KILOPARSEC-SCALE STAR FORMATION LAW AT REDSHIFT 4: WIDESPREAD, HIGHLY EFFICIENT STAR FORMATION IN THE DUST-OBSCURED STARBURST GALAXY GN20

    SciTech Connect

    Hodge, J. A.; Riechers, D.; Decarli, R.; Walter, F.; Carilli, C. L.; Daddi, E.

    2015-01-01

    We present high-resolution observations of the 880 μm (rest-frame FIR) continuum emission in the z = 4.05 submillimeter galaxy GN20 from the IRAM Plateau de Bure Interferometer (PdBI). These data resolve the obscured star formation (SF) in this unlensed galaxy on scales of 0.''3 × 0.''2 (∼2.1 × 1.3 kpc). The observations reveal a bright (16 ± 1 mJy) dusty starburst centered on the cold molecular gas reservoir and showing a bar-like extension along the major axis. The striking anti-correlation with the Hubble Space Telescope/Wide Field Camera 3 imaging suggests that the copious dust surrounding the starburst heavily obscures the rest-frame UV/optical emission. A comparison with 1.2 mm PdBI continuum data reveals no evidence for variations in the dust properties across the source within the uncertainties, consistent with extended SF, and the peak star formation rate surface density (119 ± 8 M {sub ☉} yr{sup –1} kpc{sup –2}) implies that the SF in GN20 remains sub-Eddington on scales down to 3 kpc{sup 2}. We find that the SF efficiency (SFE) is highest in the central regions of GN20, leading to a resolved SF law with a power-law slope of Σ{sub SFR} ∼ Σ{sub H{sub 2}{sup 2.1±1.0}}, and that GN20 lies above the sequence of normal star-forming disks, implying that the dispersion in the SF law is not due solely to morphology or choice of conversion factor. These data extend previous evidence for a fixed SFE per free-fall time to include the star-forming medium on ∼kiloparsec scales in a galaxy 12 Gyr ago.

  8. Nuclear infrared emission and the colors of IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Hill, Gary J.

    1987-01-01

    J, H, K, L', and N observations of galaxies detected at 12 microns by IRAS are combined with IRAS flux densities to investigate the relationship between the infrared sizes and colors of galaxian infrared sources. It is found that typical IRAS galaxies have 10 micron radii of 0.5 to 2.0 kpc, while active galaxies and galaxies with higher 25 to 60 micron color temperatures are smaller. One unusal object, 23060+0505, is at high redshift and has an infrared luminosity of 1.5 x 10 to the 12th power L sub 0. Its 1 to 100 micron energy distribution resembles that of a Seyfert 1 galaxy, but it shows very little sign of broad line emission in the visible. Its properties suggest that it may be a prototype for a class of highly obscured active galaxy.

  9. 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.

  10. 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.

  11. 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.

  12. The composite nature of Dust-Obscured Galaxies (DOGs) at z ˜ 2-3 in the COSMOS field - I. A far-infrared view

    NASA Astrophysics Data System (ADS)

    Riguccini, L.; Le Floc'h, E.; Mullaney, J. R.; Menéndez-Delmestre, K.; Aussel, H.; Berta, S.; Calanog, J.; Capak, P.; Cooray, A.; Ilbert, O.; Kartaltepe, J.; Koekemoer, A.; Lutz, D.; Magnelli, B.; McCracken, H.; Oliver, S.; Roseboom, I.; Salvato, M.; Sanders, D.; Scoville, N.; Taniguchi, Y.; Treister, E.

    2015-09-01

    Dust-Obscured Galaxies (DOGs) are bright 24 μm-selected sources with extreme obscuration at optical wavelengths. They are typically characterized by a rising power-law continuum of hot dust (TD ˜ 200-1000 K) in the near-IR indicating that their mid-IR luminosity is dominated by an active galactic nucleus (AGN). DOGs with a fainter 24 μm flux display a stellar bump in the near-IR and their mid-IR luminosity appears to be mainly powered by dusty star formation. Alternatively, it may be that the mid-IR emission arising from AGN activity is dominant but the torus is sufficiently opaque to make the near-IR emission from the AGN negligible with respect to the emission from the host component. In an effort to characterize the astrophysical nature of the processes responsible for the IR emission in DOGs, this paper exploits Herschel data (PACS + SPIRE) on a sample of 95 DOGs within the COSMOS field. We derive a wealth of far-IR properties (e.g. total IR luminosities; mid-to-far-IR colours; dust temperatures and masses) based on spectral energy distribution fitting. Of particular interest are the 24 μm-bright DOGs (F24 μm > 1 mJy). They present bluer far-IR/mid-IR colours than the rest of the sample, unveiling the potential presence of an AGN. The AGN contribution to the total 8-1000 μm flux increases as a function of the rest-frame 8 μm-luminosity irrespective of the redshift. This confirms that faint DOGs (L8 μm < 1012 L⊙) are dominated by star formation while brighter DOGs show a larger contribution from an AGN.

  13. 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

  14. BROAD Hβ EMISSION-LINE VARIABILITY IN A SAMPLE OF 102 LOCAL ACTIVE GALAXIES

    SciTech Connect

    Runco, Jordan N.; Cosens, Maren; Bennert, Vardha N.; Scott, Bryan; Komossa, S.; Malkan, Matthew A.; Treu, Tommaso; Lazarova, Mariana S.; Auger, Matthew W.; Park, Daeseong E-mail: mcosens@calpoly.edu E-mail: malkan@astro.ucla.edu E-mail: lazarovam2@unk.edu E-mail: daeseongpark@kasi.re.kr

    2016-04-10

    A sample of 102 local (0.02 ≤ z ≤ 0.1) Seyfert galaxies with black hole masses M{sub BH} > 10{sup 7}M{sub ⊙} was selected from the Sloan Digital Sky Survey (SDSS) and observed using the Keck 10 m telescope to study the scaling relations between M{sub BH} and host galaxy properties. We study profile changes of the broad Hβ emission line within the three to nine year time frame between the two sets of spectra. The variability of the broad Hβ emission line is of particular interest, not only because it is used to estimate M{sub BH}, but also because its strength and width are used to classify Seyfert galaxies into different types. At least some form of broad-line variability (in either width or flux) is observed in the majority (∼66%) of the objects, resulting in a Seyfert-type change for ∼38% of the objects, likely driven by variable accretion and/or obscuration. The broad Hβ line virtually disappears in 3/102 (∼3%) extreme cases. We discuss potential causes for these changing look active galactic nuclei. While similar dramatic transitions have previously been reported in the literature, either on a case-by-case basis or in larger samples focusing on quasars at higher redshifts, our study provides statistical information on the frequency of Hβ line variability in a sample of low-redshift Seyfert galaxies.

  15. The "red shelf" of the Hβ line in the Seyfert 1 galaxies RXS J01177+3637 and HS 0328+05.

    NASA Astrophysics Data System (ADS)

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

    2002-03-01

    A few Seyfert 1s have a Hβ profile with a red wing usually called the "red shelf". The most popular interpretation of this feature is that it is due to broad redshifted lines of Hβ and [O III]λλ4959, 5007; we have observed two Seyfert 1s displaying a "red shelf" and showed that in these two objects the main contributor is most probably the He I λλ4922, 5016 lines having the velocity and width of the broad Hβ component. There is no evidence for the presence of a broad redshifted component of Hβ or [O III] in any of these two objects.

  16. Role of feedback in AGN-host coevolution: A study from partially obscured active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2015-05-01

    Partially obscured AGNs within a redshift range z = 0.011 ∼ 0.256 are used to re-study the role of feedback in the AGN-host coevolution issue in terms of their [OIII] λ 5007 emission line profile. The spectra of these objects enable us to determine the AGN's accretion properties directly from their broad H α emission. This is essential for getting rid of the "circular reasoning" in our previous study of narrow emission-line galaxies, in which the [OIII] emission line was used not only as a proxy of AGN's bolometric luminosity, but also as a diagnostic of outflow. In addition, the measurement of Dn (4000) index is improved by removing an underlying AGN's continuum according to the corresponding broad H α emission. With these improvements, we confirm and reinforce the correlation between L /LEdd and stellar population age. More important is that this correlation is found to be related to both [OIII] line blue asymmetry and bulk blueshift velocity, which suggests a linkage between SMBH growth and host star formation through the feedback process. The current sample of partially obscured AGNs shows that the composite galaxies have younger host stellar population, higher Eddington ratio, less significant [OIII] blue wing and smaller bulk [OIII] line shift than do the Seyfert galaxies.

  17. Obscured accretion from AGN surveys

    NASA Astrophysics Data System (ADS)

    Vignali, Cristian

    2014-07-01

    Recent models of super-massive black hole (SMBH) and host galaxy joint evolution predict the presence of a key phase where accretion, traced by obscured Active Galactic Nuclei (AGN) emission, is coupled with powerful star formation. Then feedback processes likely self-regulate the SMBH growth and quench the star-formation activity. AGN in this important evolutionary phase have been revealed in the last decade via surveys at different wavelengths. On the one hand, moderate-to-deep X-ray surveys have allowed a systematic search for heavily obscured AGN, up to very high redshifts (z~5). On the other hand, infrared/optical surveys have been invaluable in offering complementary methods to select obscured AGN also in cases where the nuclear X-ray emission below 10 keV is largely hidden to our view. In this review I will present my personal perspective of the field of obscured accretion from AGN surveys.

  18. Mid-IR Properties of Seyferts: Spitzer IRS Spectroscopy of the IRAS 12 μm Seyfert Sample

    NASA Astrophysics Data System (ADS)

    Charmandaris, Vassilis; Wu, Yanling; Huang, Jiasheng; Spinoglio, Luigi; Tommasin, Silvia

    2010-05-01

    We performed an analysis of the mid-infrared properties of the 12 μm Seyfert sample, a complete unbiased 12 μm flux limited sample of local Seyfert galaxies selected from the IRAS Faint Source Catalog based on low-resolution spectra obtained with the Infrared Spectrograph (IRS) on-board Spitzer Space Telescope. A detailed presentation of this analysis is discussed by Wu et al. (2009). We find that, on average, the 15-30 μm slope of the continuum is < α15-30> = -0.85 ± 0.61 for Seyfert 1s and -1.53 ± 0.84 for Seyfert 2s, and there is substantial scatter in each type. Moreover, nearly 32% of Seyfert 1s, and 9% of Seyfert 2s, display a peak in the mid-infrared spectrum at 20 μm, which is attributed to an additional hot dust component. The polycyclic aromatic hydrocarbon (PAH) equivalent width decreases with increasing dust temperature, as indicated by the global infrared color of the host galaxies. However, no statistical difference in PAH equivalent width is detected between the two Seyfert types of the same bolometric luminosity. Finally, we propose a new method to estimate the AGN contribution to the integrated 12 μm galaxy emission, by subtracting the “star formation” component in the Seyfert galaxies, making use of the tight correlation between PAH 11.2 μm luminosity and 12 μm luminosity for star forming galaxies.

  19. Infrared Emission from the Smallest Active Galaxies

    NASA Astrophysics Data System (ADS)

    Barth, Aaron; Greene, Jenny; Ho, Luis

    2006-05-01

    Virtually all of our current knowledge of black hole demographics, both in nearby inactive galaxies and in AGNs, comes from observations of black holes with masses between a few million and a few billion solar masses in host galaxies with stellar velocity dispersions between about 70 and 400 km/sec. Searching for smaller black holes in low-mass galaxies can yield important clues to the origin and early evolution of supermassive black holes, and AGN surveys are the best available way to identify such objects. Using the Sloan Digital Sky Survey, we have identified 19 Seyfert 1 galaxies with black hole mass below 10^6 solar masses (Greene & Ho 2004), and 20 Seyfert 2 galaxies having stellar velocity dispersions smaller than 70 km/sec as determined by new Keck observations. These AGN samples offer a unique opportunity to study the very early growth stages of black holes and their host galaxies. Spitzer observations of mid-infrared emission will be the best available calorimeter of the energetics of these tiny AGNs. Our primary goal is to determine the infrared contribution to the bolometric luminosities, which will be a key to understanding the black hole accretion rates. From the infrared spectral shapes we will constrain the dust temperatures and search for silicate features in emission or absorption that may indicate the presence of an obscuring torus, and which will help to determine whether the Type 1 and Type 2 objects differ primarily as a result of our viewing angle, as in classic AGN unified models. PAH features and narrow emission lines will be used to diagnose the relative contributions of AGN and star formation to the infrared luminosity. To accomplish these goals, we request IRS staring-mode spectroscopy in the SL2, SL1, LL2, and LL1 settings for our Sloan-selected sample of 19 Seyfert 1s and 20 Seyfert 2s, as well as NGC 4395 and POX 52, which are the prototypical nearby examples of Seyfert nuclei in dwarf host galaxies.

  20. 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

  1. Constraints on the broad-line region properties and extinction in local Seyferts

    NASA Astrophysics Data System (ADS)

    Schnorr-Müller, Allan; Davies, R. I.; Korista, K. T.; Burtscher, L.; Rosario, D.; Storchi-Bergmann, T.; Contursi, A.; Genzel, R.; Graciá-Carpio, J.; Hicks, E. K. S.; Janssen, A.; Koss, M.; Lin, M.-Y.; Lutz, D.; Maciejewski, W.; Müller-Sánchez, F.; Orban de Xivry, G.; Riffel, R.; Riffel, Rogemar A.; Schartmann, M.; Sternberg, A.; Sturm, E.; Tacconi, L.; Veilleux, S.; Ulrich, O. A.

    2016-11-01

    We use high-spectral resolution (R > 8000) data covering 3800-13 000 Å to study the physical conditions of the broad-line region (BLR) of nine nearby Seyfert 1 galaxies. Up to six broad H I lines are present in each spectrum. A comparison - for the first time using simultaneous optical to near-infrared observations - to photoionization calculations with our devised simple scheme yields the extinction to the BLR at the same time as determining the density and photon flux, and hence distance from the nucleus, of the emitting gas. This points to a typical density for the H I emitting gas of 1011 cm-3 and shows that a significant amount of this gas lies at regions near the dust sublimation radius, consistent with theoretical predictions. We also confirm that in many objects, the line ratios are far from case B, the best-fitting intrinsic broad-line Hα/H β ratios being in the range 2.5-6.6 as derived with our photoionization modelling scheme. The extinction to the BLR, based on independent estimates from H I and He II lines, is AV ≤ 3 for Seyfert 1-1.5s, while Seyfert 1.8-1.9s have AV in the range 4-8. A comparison of the extinction towards the BLR and narrow-line region (NLR) indicates that the structure obscuring the BLR exists on scales smaller than the NLR. This could be the dusty torus, but dusty nuclear spirals or filaments could also be responsible. The ratios between the X-ray absorbing column NH and the extinction to the BLR are consistent with the Galactic gas-to-dust ratio if NH variations are considered.

  2. Exploring the molecular chemistry and excitation in obscured luminous infrared galaxies. An ALMA mm-wave spectral scan of NGC 4418

    NASA Astrophysics Data System (ADS)

    Costagliola, F.; Sakamoto, K.; Muller, S.; Martín, S.; Aalto, S.; Harada, N.; van der Werf, P.; Viti, S.; Garcia-Burillo, S.; Spaans, M.

    2015-10-01

    Context. Extragalactic observations allow the study of molecular chemistry and excitation under physical conditions which may differ greatly from those found in the Milky Way. The compact, obscured nuclei (CON) of luminous infrared galaxies (LIRG) combine large molecular columns with intense infrared (IR), ultra-violet (UV), and X- radiation and represent ideal laboratories for the study of the chemistry of the interstellar medium (ISM) under extreme conditions. Aims: Our aim was to obtain for the first time a multi-band spectral scan of a LIRG, and to derive molecular abundances and excitation to be compared to other Galactic and extragalactic environments. Methods: We obtained an ALMA Cycle 0 spectral scan of the dusty LIRG NGC 4418, spanning a total of 70.7 GHz in bands 3, 6, and 7. We use a combined local thermal equilibrium (LTE) and non-LTE (NLTE) fit of the spectrum in order to identify the molecular species and to derive column densities and excitation temperatures. We derive molecular abundances and compare them with other Galactic and extragalactic sources by means of a principal component analysis. Results: We detect 317 emission lines from a total of 45 molecular species, including 15 isotopic substitutions and 6 vibrationally excited variants. Our LTE/NLTE fit find kinetic temperatures from 20 to 350 K, and densities between 105 and 107 cm-3. The spectrum is dominated by vibrationally excited HC3N, HCN, and HNC, with vibrational temperatures from 300 to 450 K. We find that the chemistry of NCG 4418 is characterized by high abundances of HC3N, SiO, H2S, and c-HCCCH but a low CH3OH abundance. A principal component analysis shows that NGC 4418 and Arp 220 share very similar molecular abundances and excitation, which clearly set them apart from other Galactic and extragalactic environments. Conclusions: Our spectral scan confirms that the chemical complexity in the nucleus of NGC 4418 is one of the highest ever observed outside our Galaxy. The similar

  3. Discovery of a population of bulgeless galaxies with extremely red MID-IR colors: Obscured AGN activity in the low-mass regime?

    SciTech Connect

    Satyapal, S.; Secrest, N. J.; McAlpine, W.; Rosenberg, J. L.; Ellison, S. L.; Fischer, J.

    2014-04-01

    In contrast to massive, bulge hosting galaxies, very few supermassive black holes (SMBHs) are known in either low-mass or bulgeless galaxies. Such a population could provide clues to the origins of SMBHs and to secular pathways for their growth. Using the all-sky Wide-field Infrared Survey Explorer (WISE ) survey, and bulge-to-disk decompositions from the Sloan Digital Sky Survey (SDSS) Data Release 7, we report the discovery of a population of local (z < 0.3) bulgeless disk galaxies with extremely red mid-infrared colors which are highly suggestive of a dominant active galactic nucleus (AGN), despite having no optical AGN signatures in their SDSS spectra. Using various mid-infrared selection criteria from the literature, there are between 30 and over 300 bulgeless galaxies with possible AGNs. Other known scenarios that can heat the dust to high temperatures do not appear to explain the observed colors of this sample. If these galaxies are confirmed to host AGNs, this study will provide a breakthrough in characterizing the properties of SMBHs in the low bulge mass regime and in understanding their relation with their host galaxies. Mid-infrared selection identifies AGNs that dominate their host galaxy's emission and therefore reveal a different AGN population than that uncovered by optical studies. We find that the fraction of all galaxies identified as candidate AGNs by WISE is highest at lower stellar masses and drops dramatically in higher mass galaxies, in striking contrast to the findings from optical studies.

  4. Delving into X-ray obscuration of type 2 AGN, near and far

    SciTech Connect

    LaMassa, Stephanie M.; Meg Urry, C.; Yaqoob, Tahir; Ptak, Andrew F.; Gandhi, Poshak

    2014-05-20

    Using self-consistent, physically motivated models, we investigate the X-ray obscuration in 19 Type 2 [O III] 5007 Å selected active galactic nuclei (AGNs), 9 of which are local Seyfert 2 galaxies and 10 of which are Type 2 quasar candidates. We derive reliable line-of-sight and global column densities for these objects, which is the first time this has been reported for an AGN sample; four AGNs have significantly different global and line-of-sight column densities. Five sources are heavily obscured to Compton-thick. We comment on interesting sources revealed by our spectral modeling, including a candidate 'naked' Sy2. After correcting for absorption, we find that the ratio of the rest-frame, 2-10 keV luminosity (L{sub 2-10} {sub keV,} {sub in}) to L{sub [O} {sub III]} is 1.54 ± 0.49 dex which is essentially identical to the mean Type 1 AGN value. The Fe Kα luminosity is significantly correlated with L{sub [O} {sub III]} but with substantial scatter. Finally, we do not find a trend between L {sub 2-10keV,} {sub in} and global or line-of-sight column density, between column density and redshift, between column density and scattering fraction, or between scattering fraction and redshift.

  5. Penetrating the "zone of avoidance". III. A survey for obscured galaxies in the region 120deg<=l<=130deg, -10deg<=b<=+10deg.

    NASA Astrophysics Data System (ADS)

    Lercher, G.; Kerber, F.; Weinberger, R.

    1996-06-01

    As the third part in a series of papers on galaxies in the "zone of avoidance" (ZOA) of the Milky Way we present a compilation of 1161 galaxies discovered during a systematic search on Palomar Observatory Sky Survey (POSS) red-sensitive prints. The region searched comprises 200 square degrees, at 120deg<=l<=130deg, -10deg<=b<=+10deg. In addition to galactic, equatorial and rectangular coordinates, we list maximum and minimum optical diameters derived from both the red- and blue-sensitive prints, could assign a morphological type to some of the objects and made cross-checks with the IRAS PSC and several radio catalogues. A test for completeness suggests, that our catalogue should be complete down to a limiting galaxy-diameter of 0.35'. An asymmetric distribution of the galaxies with respect to the galactic equator was found and is discussed by comparing it with the locations of optically visible dust clouds and/or the distribution of IR-emitting dust material. A comparison between the distribution of the galaxies and the 100μ IRAS intensity maps led to the identification of four possible clusterings. As a byproduct of our galaxy search, two new planetary nebulae, nebulous stars at the position of a strong cold IRAS point source, and a nearby dwarf irregular galaxy could be detected.

  6. Optical and infrared spectrophotometry of 18 Markarian galaxies

    NASA Technical Reports Server (NTRS)

    Becklin, E. E.; Neugebauer, G.; Oke, J. B.; Searle, L.

    1975-01-01

    Slit spectra, spectrophotometric scans and infrared broad band observations are presented. Eight of the program galaxies can be classified as Seyfert galaxies. Arguments are given that thermal, nonthermal and stellar radiation components were present. One group of Seyfert galaxies was characterized both by the presence of a high density region of gas and by a continuum dominated by nonthermal radiation. The continua of the remaining program Seyferts, which did not have a high density region of gas, were dominated by thermal radiation from dust and a stellar continuum. Ten of the galaxies, which are not Seyfert galaxies, are shown to be examples of extragalactic H 2 regions.

  7. The mass and spin of the extreme Narrow Line Seyfert 1 Galaxy 1H 0707-495 and its implications for the trigger for relativistic jets

    NASA Astrophysics Data System (ADS)

    Done, Chris; Jin, Chichuan

    2016-08-01

    Relativistic reflection models of the X-ray spectrum of the `complex' Narrow Line Seyfert 1 (NLS1) 1H 0707-495 require a high-spin, moderate-inclination, low-mass black hole. With these parameters fixed, the observed optical/UV emission directly determines the mass accretion rate through the outer disc and hence predicts the bolometric luminosity. This is 140-260 times the Eddington limit. Such a disc should power a strong wind, and winds are generically expected to be clumpy. Changing inclination angle with respect to a clumpy wind structure gives a possible explanation for the otherwise puzzling difference between `complex' NLS1 such as 1H 0707-495 and `simple' ones like PG 1244+026. Lines of sight which intercept the wind show deep absorption features at iron from the hot phase of the wind, together with stochastic dips and complex absorption when the clumps occult the X-ray source (complex NLS1), whereas both these features are absent for more face-on inclination (simple NLS1). This geometry is quite different from the clean view of a flat disc which is assumed for the spin measurements in relativistic reflection models, so it is possible that even 1H 0707-495 has low spin. If so, this re-opens the simplest and hence very attractive possibility that high black hole spin is a necessary and sufficient condition to trigger highly relativistic (bulk Lorentz factor ˜10-15) jets.

  8. The evolution of dust-obscured star formation activity in galaxy clusters relative to the field over the last 9 billion years

    NASA Astrophysics Data System (ADS)

    Alberts, Stacey; Pope, Alexandra; Brodwin, Mark; Atlee, David W.; Lin, Yen-Ting; Dey, Arjun; Eisenhardt, Peter R. M.; Gettings, Daniel P.; Gonzalez, Anthony H.; Jannuzi, Buell T.; Mancone, Conor L.; Moustakas, John; Snyder, Gregory F.; Stanford, S. Adam; Stern, Daniel; Weiner, Benjamin J.; Zeimann, Gregory R.

    2014-01-01

    We compare the star formation (SF) activity in cluster galaxies to the field from z = 0.3 to 1.5 using Herschel Spectral and Photometric Imaging REceiver 250 μm imaging and utilizing 274 clusters from the IRAC Shallow Cluster Survey (ISCS). These clusters were selected as rest-frame near-infrared overdensities over the 9 square degree Boötes field. This sample allows us to quantify the evolution of SF in clusters over a long redshift baseline without bias against active cluster systems. Using a stacking analysis, we determine the average star formation rates (SFRs) and specific SFRs (SSFR = SFR/M⋆) of stellar mass-limited (M ≥ 1.3 × 1010 M⊙), statistical samples of cluster and field galaxies, probing both the star-forming and quiescent populations. We find a clear indication that the average SF in cluster galaxies is evolving more rapidly than in the field, with field SF levels at z ≳ 1.2 in the cluster cores (r < 0.5 Mpc), in good agreement with previous ISCS studies. By quantifying the SF in cluster and field galaxies as an exponential function of cosmic time, we determine that cluster galaxies are evolving approximately two times faster than the field. Additionally, we see enhanced SF above the field level at z ˜ 1.4 in the cluster outskirts (r > 0.5 Mpc). These general trends in the cluster cores and outskirts are driven by the lower mass galaxies in our sample. Blue cluster galaxies have systematically lower SSFRs than blue field galaxies, but otherwise show no strong differential evolution with respect to the field over our redshift range. This suggests that the cluster environment is both suppressing the SF in blue galaxies on long time-scales and rapidly transitioning some fraction of blue galaxies to the quiescent galaxy population on short time-scales. We argue that our results are consistent with both strangulation and ram pressure stripping acting in these clusters, with merger activity occurring in the cluster outskirts.

  9. AN OPTICALLY OBSCURED AGN IN A LOW MASS, IRREGULAR DWARF GALAXY: A MULTI-WAVELENGTH ANALYSIS OF J1329+3234

    SciTech Connect

    Secrest, N. J.; Satyapal, S.; Gliozzi, M.; Rothberg, B.; Mowry, W. S.; Rosenberg, J. L.; Ellison, S. L.; Fischer, J.; Schmitt, H.

    2015-01-01

    Supermassive black holes (SMBHs) are found ubiquitously in large, bulge-dominated galaxies throughout the local universe, yet little is known about their presence and properties in bulgeless and low-mass galaxies. This is a significant deficiency, since the mass distribution and occupation fraction of nonstellar black holes provide important observational constraints on SMBH seed formation theories and many dwarf galaxies have not undergone major mergers that would erase information on their original black hole population. Using data from the Wide-field Infrared Survey Explorer, we discovered hundreds of bulgeless and dwarf galaxies that display mid-infrared signatures of extremely hot dust highly suggestive of powerful accreting massive black holes, despite having no signatures of black hole activity at optical wavelengths. Here we report, in our first follow-up X-ray investigation of this population, that the irregular dwarf galaxy J132932.41+323417.0 (z = 0.0156) contains a hard, unresolved X-ray source detected by XMM-Newton with luminosity L {sub 2-10} {sub keV} = 2.4 × 10{sup 40} erg s{sup –1}, over two orders of magnitude greater than that expected from star formation, strongly suggestive of the presence of an accreting massive black hole. While enhanced X-ray emission and hot dust can be produced in extremely low metallicity environments, J132932.41+323417.0 is not extremely metal poor (≈40% solar). With a stellar mass of 2.0 × 10{sup 8} M {sub ☉}, this galaxy is similar in mass to the Small Magellanic Cloud, and is one of the lowest mass galaxies with evidence for a massive nuclear black hole currently known.

  10. THE BLACK HOLE MASSES AND STAR FORMATION RATES OF z>1 DUST OBSCURED GALAXIES: RESULTS FROM KECK OSIRIS INTEGRAL FIELD SPECTROSCOPY

    SciTech Connect

    Melbourne, J.; Soifer, B. T.; Matthews, K. E-mail: bts@ipac.caltech.edu

    2011-04-15

    We have obtained high spatial resolution Keck OSIRIS integral field spectroscopy of four z {approx} 1.5 ultra-luminous infrared galaxies that exhibit broad H{alpha} emission lines indicative of strong active galactic nucleus (AGN) activity. The observations were made with the Keck laser guide star adaptive optics system giving a spatial resolution of 0.''1 or <1 kpc at these redshifts. These high spatial resolution observations help to spatially separate the extended narrow-line regions-possibly powered by star formation-from the nuclear regions, which may be powered by both star formation and AGN activity. There is no evidence for extended, rotating gas disks in these four galaxies. Assuming dust correction factors as high as A(H{alpha}) = 4.8 mag, the observations suggest lower limits on the black hole masses of (1-9) x 10{sup 8} M{sub sun} and star formation rates <100 M{sub sun} yr{sup -1}. The black hole masses and star formation rates of the sample galaxies appear low in comparison to other high-z galaxies with similar host luminosities. We explore possible explanations for these observations, including host galaxy fading, black hole growth, and the shut down of star formation.

  11. GRB 051008: a long, spectrally hard dust-obscured GRB in a Lyman-break galaxy at z ≈ 2.8

    NASA Astrophysics Data System (ADS)

    Volnova, A. A.; Pozanenko, A. S.; Gorosabel, J.; Perley, D. A.; Frederiks, D. D.; Kann, D. A.; Rumyantsev, V. V.; Biryukov, V. V.; Burkhonov, O.; Castro-Tirado, A. J.; Ferrero, P.; Golenetskii, S. V.; Klose, S.; Loznikov, V. M.; Minaev, P. Yu.; Stecklum, B.; Svinkin, D. S.; Tsvetkova, A. E.; de Ugarte Postigo, A.; Ulanov, M. V.

    2014-08-01

    We present observations of the dark gamma-ray burst GRB 051008 provided by Swift/BAT, Swift/XRT, Konus-WIND, INTEGRAL/SPI-ACS in the high-energy domain and the Shajn, Swift/UVOT, Tautenburg, NOT, Gemini and Keck I telescopes in the optical and near-infrared bands. The burst was detected only in gamma- and X-rays and neither a prompt optical nor a radio afterglow was detected down to deep limits. We identified the host galaxy of the burst, which is a typical Lyman-break galaxy (LBG) with R-magnitude of 24.06 ± 0.10 mag. A redshift of the galaxy of z = 2.77_{-0.20}^{+0.15} is measured photometrically due to the presence of a clear, strong Lyman-break feature. The host galaxy is a small starburst galaxy with moderate intrinsic extinction (AV = 0.3) and has a star formation rate of ˜60 M⊙ yr-1 typical for LBGs. It is one of the few cases where a GRB host has been found to be a classical LBG. Using the redshift we estimate the isotropic-equivalent radiated energy of the burst to be Eiso = (1.15 ± 0.20) × 1054 erg. We also provide evidence in favour of the hypothesis that the darkness of GRB 051008 is due to local absorption resulting from a dense circumburst medium.

  12. Anatomy of the AGN in NGC 5548. VII. Swift study of obscuration and broadband continuum variability

    NASA Astrophysics Data System (ADS)

    Mehdipour, M.; Kaastra, J. S.; Kriss, G. A.; Cappi, M.; Petrucci, P.-O.; De Marco, B.; Ponti, G.; Steenbrugge, K. C.; Behar, E.; Bianchi, S.; Branduardi-Raymont, G.; Costantini, E.; Ebrero, J.; Di Gesu, L.; Matt, G.; Paltani, S.; Peterson, B. M.; Ursini, F.; Whewell, M.

    2016-04-01

    We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two, with archival observations reaching back to 2005, totalling about 670 ks of observing time. Both broadband spectral modelling and temporal rms variability analysis are applied to the Swift data. We disentangle the variability caused by absorption, due to an obscuring weakly-ionised outflow near the disk, from variability of the intrinsic continuum components (the soft X-ray excess and the power law) originating in the disk and its associated coronae. The spectral model that we apply to this extensive Swift data is the global model that we derived for NGC 5548 from analysis of the stacked spectra from our multi-satellite campaign of 2013 (including XMM-Newton, NuSTAR, and HST). The results of our Swift study show that changes in the covering fraction of the obscurer is the primary and dominant cause of variability in the soft X-ray band on timescales of 10 days to ~5 months. The obscuring covering fraction of the X-ray source is found to range between 0.7 and nearly 1.0. The contribution of the soft excess component to the X-ray variability is often much less than that of the obscurer, but it becomes comparable when the optical-UV continuum flares up. We find that the soft excess is consistent with being the high-energy tail of the optical-UV continuum and can be explained by warm Comptonisation: up-scattering of the disk seed photons in a warm, optically thick corona as part of the inner disk. To this date, the Swift monitoring of NGC 5548 shows that the obscurer has been continuously present in our line of sight for at least 4 years (since at least February 2012).

  13. Host Galaxy Properties of the Swift BAT Ultra Hard X-Ray Selected AGN

    NASA Technical Reports Server (NTRS)

    Koss, Michael; Mushotzky, Richard; Veilleux, Sylvain; Winter, Lisa M.; Baumgartner, Wayne; Tueller, Jack; Gehrels, Neil; Valencic, Lynne

    2011-01-01

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) AGN with host galaxy optical data to date, with 185 nearby (z<0.05), moderate luminosity AGN from the Swift Burst Alert Telescope (BAT) sample. The BAT AGN host galaxies have intermediate optical colors (u -- r and g -- r) that are bluer than a comparison sample of inactive galaxies and optically selected AGN from the Sloan Digital Sky Survey (SDSS) which are chosen to have the same stellar mass. Based on morphological classifications from the RC3 and the Galaxy Zoo, the bluer colors of BAT AGN are mainly due to a higher fraction of mergers and massive spirals than in the comparison samples. BAT AGN in massive galaxies (log Stellar Mass >10.5) have a 5 to 10 times higher rate of spiral morphologies than in SDSS AGN or inactive galaxies. We also see enhanced far-IR emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGN are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line (NL) BAT AGN have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III] Lambda 5007. There is also a correlation between the stellar mass and X-ray emission. The BAT AGN in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as whole. In agreement with the Unified Model of AGN, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of obscuration such as X-ray column density or Seyfert type. The high fraction of massive spiral galaxies and galaxy mergers in BAT AGN suggest that host galaxy morphology is related to the activation and fueling of local AGN.

  14. Coordinated X-ray/ground-based monitoring of Seyfert 1s

    NASA Astrophysics Data System (ADS)

    Uttley, P.

    2003-05-01

    Co-ordinated X-ray and optical monitoring programs are beginning to reveal the complex connection between the X-ray and optical emitting regions in the central engines of Seyfert galaxies. I will discuss the current state of our knowledge of the optical/X-ray connection in Seyferts, and demonstrate how Lobster, in conjunction with the new generation of ground based robotic observatories, will greatly enhance our understanding of the origins of the continuum emission in AGN.

  15. The Evolution of Obscuration in AGN

    NASA Astrophysics Data System (ADS)

    Treister, Ezequiel; Urry, M.; Virani, S.

    2006-09-01

    One fundamental ingredient in our understanding of the AGN population is the ratio of obscured to unobscured AGN and whether this ratio depends on other parameters like intrinsic luminosity or redshift. Observationally, deep X-ray surveys found that the obscured AGN fraction depends on luminosity. However, the dependence on redshift is less clear. In this work, we constructed the largest sample to date of AGN selected in hard X-rays, containing a total of 1229 sources, 631 of them obscured, with a high spectroscopic completeness in order to study the possible dependence of the fraction of obscured sources with redshift and/or luminosity. We confirm that this fraction decreases with increasing luminosity as previously reported and found that at the same time it increases with increasing redshift. This is the first time that this evolution is significantly detected using only optical spectroscopy to separate obscured and unobscured AGN. Additionally, we use the spectral shape and intensity of the X-ray background as a separate constraint on the evolution of the obscured AGN fraction finding consistent results. This result can be interpreted as an evolution in the location of the obscuration, from the central parsec-scale region (the torus) at low redshift to kiloparsec scales (the host galaxy) at high redshift, as it is known that most galaxies contained more dust in the past. Using these results, we calculate the integrated bolometric AGN emission finding it to be at most 5% of the total extragalactic light. Hence, while AGN contribute most of the light at X-ray wavelengths, they constitute only a small fraction of the integrated extragalactic light. We thank the support of the Centro de Astrof\\'{\\i}sica FONDAP and from NASA/{\\it INTEGRAL} grant NNG05GM79G.

  16. Real time obscuration monitoring

    NASA Astrophysics Data System (ADS)

    Agricola, Koos

    2016-09-01

    Recently a real time particle deposition monitoring system is developed. After discussions with optical system engineers a new feature has been added. This enables the real time monitoring of obscuration of exposed optical components by counting the deposited particles and sizing the obscuration area of each particle. This way the Particle Obscuration Rate (POR) can be determined. The POR can be used to determine the risk of product contamination during exposure. The particle size distribution gives information on the type of potential particle sources. The deposition moments will indicate when these sources were present.

  17. Gamma-radiation with E gamma 5 MeV detected from Seyfert galaxy 3C120 and region with 1" = 190 deg and b" = 20 deg

    NASA Technical Reports Server (NTRS)

    Damle, S. V.; Fradkin, M. I.; Iyudin, A. F.; Kirillov-Ugryumov, V. G.; Kotov, Y. D.; Kurnosova, L. V.; Smirnov, Y. V.; Yurov, V. N.

    1985-01-01

    The observation of the Galaxy anticenter region in gamma-rays with E gamma = 5 / 100 MeV was made by gamma-telescope Natalya-1 in a balloon flight. The flight was performed at the ceiling 5.1 + or - 0.1 g/sq cm, magnetic cutoff being 17 GV. The description of the instrument and the analysis of the experiment conditions are given. The tracks of electron-positron pairs generated by gamma-quanta in the convertors were detected by wire spark chambers. The recorded events were classified manually by an operator using a graphic display into three classes: pairs, single and bad events. The arrival angle of gamma-quanta and their energy for selected gamma-ray events (pairs and singles) were determined through multiple scattering of pair components in the convertors. On the basis of the data obtained the celestial maps were made in gamma-rays for E sub gamma 5 MeV and E gamma 20 MeV energy ranges.

  18. Seyfert 1 composite spectrum using SDSS Legacy survey data

    NASA Astrophysics Data System (ADS)

    Pol, Nihan; Wadadekar, Yogesh

    2017-02-01

    We present a rest-frame composite spectrum for Seyfert 1 galaxies using spectra obtained from the 12th Data Release of the Sloan Digital Sky Survey. The spectrum is constructed by combining data from a total of 10112 galaxies, spanning a redshift range of 0-0.793. We produce an electronic table of the median and geometric mean composite Seyfert 1 spectrum. We measure the spectral index of the composite spectrum, and compare it with that of the composite quasar spectrum. We also measure the flux and width of the strong emission lines present in the composite spectrum. We compare the entire spectrum with the quasar spectrum in the context of the unification model for active galactic nuclei. The two composite spectra match extremely well in the blue part of the spectrum, while there is an offset in flux in the red portion of the spectrum.

  19. Hubble Space Telescope and Very Large Array Observations of the H2O Gigamaser Galaxy TXS 2226-184.

    PubMed

    Falcke; Wilson; Henkel; Brunthaler; Braatz

    2000-02-10

    We present Hubble Space Telescope/Wide-Field and Planetary Camera 2 images in Halpha + [N ii] lambdalambda6548, 6583 lines and continuum radiation and a VLA map at 8 GHz of the H2O gigamaser galaxy TXS 2226-184. This galaxy has the most luminous H2O maser emission known to date. Our red continuum images reveal a highly elongated galaxy with a dust lane crossing the nucleus. The surface brightness profile is best fitted by a bulge plus exponential disk model, favoring classification as a highly inclined spiral galaxy (i=70&j0;). The color map confirms that the dust lane is aligned with the galaxy major axis and is crossing the putative nucleus. The Halpha + [N ii] map exhibits a gaseous, jetlike structure perpendicular to the nuclear dust lane and the galaxy major axis. The radio map shows compact, steep spectrum emission that is elongated in the same direction as the Halpha + [N ii] emission. By analogy with Seyfert galaxies, we therefore suspect that this alignment reflects an interaction between the radio jet and the interstellar medium. The axes of the nuclear dust disk, the radio emission, and the optical line emission apparently define the axis of the active galactic nucleus. The observations suggest that in this galaxy the nuclear accretion disk, obscuring torus, and large-scale molecular gas layer are roughly coplanar. Our classification of the host galaxy strengthens the trend for megamasers to be found preferentially in highly inclined spiral galaxies.

  20. NGC 4388- Spectral Studies of the First Seyfert 2 Seen by INTEGRAL

    NASA Technical Reports Server (NTRS)

    Beckman, V.; Gehrels, N.; Favre, P.; Courvoisier, T. J.-L.; Walter, R.; Malzac, J.; Petrucci, P.-O.

    2004-01-01

    We present first INTEGRAL and XMM-Newton ob- servations of a Seyfert galaxy, the type 2 AGN NGC 4388. Several INTEGRAL observations performed in 2003 allow us to study the spectrum in the 20 - 300 keV range. In addition two XMM-Newton observations give detailed insight into the 0.2 - 10 keV emission. Comparison with previous observations by BeppoSAX, SIGMA and CGROIOSSE show that the overall spectrum for soft X-rays up to the gamma-rays can be described by a highly absorbed and variable non-thermal component in addition to constant non-absorbed thermal emission of low abundance (2 - 5%Za), plus a constant Fe K alpha line. The hard X-ray component is well described by a simple power law with a mean photon index of 1 = 1.7. During the INTEGRAL observations the flux at 100 keV increased by a factor of 1.5. The analysis of XMM-Newton data implies that the emission below 3 keV is decoupled from the AGN and probably due to extended emission as seen in Chandra observations. The constant iron line emission is apparently also decoupled from the direct emission of the central engine and likely to be generated in the obscuring material, e.g. in the molecular torus or even further away.

  1. SUBMILLIMETER ARRAY/PLATEAU DE BURE INTERFEROMETER MULTIPLE LINE OBSERVATIONS OF THE NEARBY SEYFERT 2 GALAXY NGC 1068: SHOCK-RELATED GAS KINEMATICS AND HEATING IN THE CENTRAL 100 pc?

    SciTech Connect

    Krips, M.; Neri, R.; Martin, S. E-mail: neri@iram.fr

    2011-07-20

    We present high angular resolution (0.''5-2.''0) observations of the millimeter continuum and the {sup 12}CO(J = 3-2), {sup 13}CO(J = 3-2), {sup 13}CO(J = 2-1), C{sup 18}O(J = 2-1), HCN(J = 3-2), HCO{sup +}(J = 4-3), and HCO{sup +}(J = 3-2) line emission in the circumnuclear disk (r {approx}< 100 pc) of the prototypical Seyfert 2 galaxy NGC 1068, carried out with the Submillimeter Array. We also include in our analysis new {sup 13}CO(J = 1-0) and improved {sup 12}CO(J = 2-1) observations of NGC 1068 at high angular resolution (1.''0-2.''0) and sensitivity, conducted with the Institute de Radioastronomie Millimetrique Plateau de Bure Interferometer. Based on the complex dynamics of the molecular gas emission indicating non-circular motions in the central {approx}100 pc, we propose a scenario in which part of the molecular gas in the circumnuclear disk of NGC 1068 is blown radially outward as a result of shocks. This shock scenario is further supported by quite warm (T{sub kin} {>=} 200 K) and dense (n(H{sub 2}) {approx_equal} 10{sup 4} cm{sup -3}) gas constrained from observed molecular line ratios. The HCN abundance in the circumnuclear disk is found to be [HCN]/[{sup 12}CO] {approx} 10{sup -3.5}. This is slightly higher than the abundances derived for Galactic and extragalactic star-forming/starbursting regions. This result lends further support to X-ray-enhanced HCN formation in the circumnuclear disk of NGC 1068 as suggested by earlier studies. The HCO{sup +} abundance ([HCO{sup +}]/[{sup 12}CO] {approx} 10{sup -5}) appears to be somewhat lower than that of Galactic and extragalactic star-forming/starbursting regions. When trying to fit the centimeter-to-millimeter continuum emission by different thermal and non-thermal processes, it appears that electron-scattered synchrotron emission yields the best results while thermal free-free emission seems to overpredict the millimeter continuum emission.

  2. Nuevas Galaxias Seyfert 1 Australes

    NASA Astrophysics Data System (ADS)

    Maza, J.; Ruiz, M. T.

    1987-05-01

    En 1984 se inició una extensión del "survey" de Tololo que de- sarrollara en 1975 Smith, con la cámara Curtis-Schmidt y el prisma UV delgado. Utilizando placas IIIaJ horneadas, sin filtro, expues tas 90 minutos sin ensanchamiento se han obtenido a la fecha más de 150 placas que cubren la zona entre -20° y -45° a latitudes galácticas mayores de 20°; se presenta un detalle de las franjas que comprende el survey Calan-Tololo, indicando el grado de completitud de las mismas. Se ha encontrado un gran número de galaxias con líneas de emisión entre las cuales las más frecuentes, más de 300, son galaxias irregulares con formación estelar violenta ("starburst galaxies"). Se ha encontrado un número de cuasares cercano a 100; casi todos ellos tienen la linea Lyman alfa en la zona entre 3300 y 5300 A, que corresponde a un rango de corrimientosal rojo 1.7< z <3.3 el cuasar con mayor corri- miento al rojo encontrado a la fecha en el survey tiene z = 3.1. La información detallada sobre cuasares y galaxias tipo "starburst" será presentada en otro lugar. Entre los objetos más interesantes encontrados en el survey Calán- Tololo destacan unas 50 nuevas galaxias Seyfert 1. Estas galaxias han sido encontradas por su fuerte exceso UV y su brillante núcleo, más que por sus intensas lineas de emisión. Hemos observado espectroscópicamente, en el Observatorio Interamericano de Cerro Tololo, 37 de ellas para las cuales se presentan cartas de identificación, coordenadas y los datos espectroscópicos obtenidos.

  3. Hexachloroethane Obscurant Replacement

    DTIC Science & Technology

    2012-01-01

    suggest that neither the alkali metal hydroxides nor chlorides are extremely toxic (11). Oral rat LD50 values are indeed lower for hydroxide salts...analyze for toxicity of combustion gases and particulates. Compositions containing boron potassium nitrate igniter blended with halide salts...variants were identified which should have improved performance. 15. SUBJECT TERMS Non- toxic obscurant, hexachloroethane smoke replacement 16

  4. Fenestration obscuration techniques

    NASA Astrophysics Data System (ADS)

    Smalley, Michael

    2007-10-01

    There are situations where it is advantageous to visually obscure through glass, to an external observer, the movement of people within a well lit room. It may be that the building use has changed or existing measures which had provided obscuration such as 'Bomb-blast' curtains have been discontinued. Recognising that implemented solutions must create the minimum disruption to outward visibility and involve the least procedural effort (be simple to use), the Centre for Protection of National Infrastructure, CPNI, commissioned this study, defining key requirements including: (a) Automatic or simple manual operation (b) Obscuration of movement within the building from outside (c) Varying levels of obscuration depending on the difference in internal and external light levels. (d) Minimum disruption to outward visibility (e) Acceptable for use on heritage and iconic sites (f) Easy to retrofit (g) Low cost This report reviews earlier work carried out into the protection of Guardrooms by the use of lighting techniques coupled with the use of reflective and screen printed films. Other innovative solutions including Electrochromatic controllable glazing which may prove more appropriate to office and commercial buildings are also considered. It is seen that some measures, (window films or blinds), are cost effective and unsophisticated while more complex automatic systems using reactive glazing can offer critical design advantages. It must be noted however that some of the key requirements are mutually exclusive and any solution chosen will always be a compromise based on client needs and circumstances.

  5. H2O Megamasers toward Radio-bright Seyfert 2 Nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, J. S.; Liu, Z. W.; Henkel, C.; Wang, J. Z.; Coldwell, G. V.

    2017-02-01

    Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H2O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 (z ∼ 0.0448), was detected four times during our observations, with a typical maser flux density of ∼30 mJy and a corresponding (very large) luminosity of ∼1135 L ⊙. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H2O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H2O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies. Based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg.

  6. HUBBLE CAPTURES AN EXTRAORDINARY AND POWERFUL ACTIVE GALAXY

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Resembling a swirling witch's cauldron of glowing vapors, the black hole-powered core of a nearby active galaxy appears in this colorful NASA Hubble Space Telescope image. The galaxy lies 13 million light-years away in the southern constellation Circinus. This galaxy is designated a type 2 Seyfert, a class of mostly spiral galaxies that have compact centers and are believed to contain massive black holes. Seyfert galaxies are themselves part of a larger class of objects called Active Galactic Nuclei or AGN. AGN have the ability to remove gas from the centers of their galaxies by blowing it out into space at phenomenal speeds. Astronomers studying the Circinus galaxy are seeing evidence of a powerful AGN at the center of this galaxy as well. Much of the gas in the disk of the Circinus spiral is concentrated in two specific rings -- a larger one of diameter 1,300 light-years, which has already been observed by ground-based telescopes, and a previously unseen ring of diameter 260 light-years. In the Hubble image, the smaller inner ring is located on the inside of the green disk. The larger outer ring extends off the image and is in the plane of the galaxy's disk. Both rings are home to large amounts of gas and dust as well as areas of major 'starburst' activity, where new stars are rapidly forming on timescales of 40 - 150 million years, much shorter than the age of the entire galaxy. At the center of the starburst rings is the Seyfert nucleus, the believed signature of a supermassive black hole that is accreting surrounding gas and dust. The black hole and its accretion disk are expelling gas out of the galaxy's disk and into its halo (the region above and below the disk). The detailed structure of this gas is seen as magenta-colored streamers extending towards the top of the image. In the center of the galaxy and within the inner starburst ring is a V-shaped structure of gas. The structure appears whitish-pink in this composite image, made up of four filters. Two

  7. Optical and infrared spectrophotometry of 18 Markarian galaxies

    NASA Technical Reports Server (NTRS)

    Neugebauer, G.; Becklin, E. E.; Oke, J. B.; Searle, L.

    1976-01-01

    Slit spectra, spectrophotometric scans, and infrared broad-band observations are presented for 18 Markarian galaxies with emission lines. Eight of the program galaxies can be classified as Seyfert galaxies. Arguments are given that thermal, nonthermal, and stellar radiation components are present. Broadly speaking, one group of Seyfert galaxies is characterized both by the presence of a high-density region of gas and by a continuum dominated by nonthermal radiation. The continua of the remaining program Seyferts, which do not have a high-density region of gas, are dominated by thermal radiation from dust and a stellar continuum. The 10 galaxies which are not Seyfert galaxies are shown to be examples of extragalactic H II regions; there is evidence for thermal emission from dust being present at 10 microns in four of these galaxies.

  8. Hot cores and cold winds in dusty galaxies

    NASA Astrophysics Data System (ADS)

    Aalto, Susanne

    2015-08-01

    Molecular gas plays a fundamental role in feeding and regulating star formation and growth of supermassive black holes (SMBH) in galaxy nuclei and is therefore a primary evolutionary parameter in starburst and AGN activity. ALMA is a powerful instrument for studying galaxy evolution using molecules as observational tools - exploiting their ability to trace dynamical, chemical and physical conditions.I will present recent high resolution ALMA results on vibrationally excited molecules (e.g. HCN, HC3N) and how they can be used to peek inside the optically thick veil of extremely obscured galaxy nuclei. These lines are efficient probes even when N(H2) exceeds 1e24 cm-2 and trace nuclear disks and bars, enclosed mass inside the dusty core - and act as direct measures of the hidden mid-infrared luminosity densities. I will show preliminary results suggesting that the vibrationally excited lines can be strongly tied to the evolutionary phase of the nuclear activity.These nuclei may also drive cold molecular winds and we have studied the CO 3-2 emission of the massive outflow of the nearby lenticular NGC1377 in exquisite detail with ALMA - revealing new surprising results on its morphology and origin. Furthermore, new ALMA spectral scans demonstrate the emerging power of astrochemistry as a tool to probe starburst and AGN evolution in obscured nuclei, AGNs and starbursts. I will discuss key molecular tracers and the astrochemistry of the obscured LIRG NGC4418 in relation to that of the nearby Seyfert galaxy NGC1068 and the ULIRG Arp220.Finally, ALMA studies of the extended molecular distributions of minor mergers and their connection to star formation efficiency, merger precursors and evolution will be briefly discussed.

  9. The Seyfert II Nature of the IRAS Source FSC10214+4724

    NASA Technical Reports Server (NTRS)

    Eisenhardt, P.; Elston, R.; McCarthy, P.; Dickinson, M.; Spinrad, H.; Jannuzi, B.; Maloney, P.

    1994-01-01

    We have observed the rest-frame optical and UV spectra of the luminous, high redshift IRAS source FSC10214+4724. We find the optical emission lines to be characterized by ratios similar to those found in Seyfert II galaxies.

  10. Misaligned Disks as Obscurers in Active Galaxies

    SciTech Connect

    Lawrence, A.; Elvis, M.; /Edinburgh U., Inst. Astron. /Harvard-Smithsonian Ctr. Astrophys.

    2010-06-02

    We review critically the evidence concerning the fraction of Active Galactic Nuclei (AGN) which appear as Type 2 AGN, carefully distinguishing strict Type 2 AGN from both more lightly reddened Type 1 AGN, and from low excitation narrow line AGN, which may represent a different mode of activity. Low excitation AGN occur predominantly at low luminosities; after removing these, true Type 2 AGN represent 58{-+}5% of all AGN, and lightly reddened Type 1 AGN a further {approx}15%. Radio, IR, and volume-limited samples all agree in showing no change of Type 2 fraction with luminosity. X-ray samples do show a change with luminosity; we discuss possible reasons for this discrepancy. We test a very simple picture which produces this Type 2 fraction with minimal assumptions. In this picture, infall from large scales occurs in random directions, but must eventually align with the inner accretion flow, producing a severely warped disk on parsec scales. If the re-alignment is dominated by tilt, with minimal twist, a wide range of covering factors is predicted in individual objects, but with an expected mean fraction of Type 2 AGN of exactly 50%. This 'tilted disc' picture predicts reasonable alignment of observed nuclear structures on average, but with distinct misalignments in individual cases. Initial case studies of the few well resolved objects show that such misalignments are indeed present.

  11. Infrared coronal emission lines and the possibility of their maser emission in Seyfert nuclei

    NASA Technical Reports Server (NTRS)

    Greenhouse, Matthew A.; Feldman, Uri; Smith, Howard A.; Klapisch, Marcel; Bhatia, Anand K.; Bar-Shalom, Abi

    1993-01-01

    Energetic emitting regions have traditionally been studied via x-ray, UV and optical emission lines of highly ionized intermediate mass elements. Such lines are often referred to as 'coronal lines' since the ions, when produced by collisional ionization, reach maximum abundance at electron temperatures of approx. 10(exp 5) - 10(exp 6) K typical of the sun's upper atmosphere. However, optical and UV coronal lines are also observed in a wide variety of Galactic and extragalactic sources including the Galactic interstellar medium, nova shells, supernova remnants, galaxies and QSOs. Infrared coronal lines are providing a new window for observation of energetic emitting regions in heavily dust obscured sources such as infrared bright merging galaxies and Seyfert nuclei and new opportunities for model constraints on physical conditions in these sources. Unlike their UV and optical counterparts, infrared coronal lines can be primary coolants of collisionally ionized plasmas with 10(exp 4) less than T(sub e)(K) less than 10(exp 6) which produce little or no optical or shorter wavelength coronal line emission. In addition, they provide a means to probe heavily dust obscured emitting regions which are often inaccessible to optical or UV line studies. In this poster, we provide results from new model calculations to support upcoming Infrared Space Observatory (ISO) and current ground-based observing programs involving infrared coronal emission lines in AGN. We present a complete list of infrared (lambda greater than 1 micron) lines due to transitions within the ground configurations 2s(2)2p(k) and 3s(2)3p(k) (k = 1 to 5) or the first excited configurations 2s2p and 3s3p of highly ionized (x greater than or equal to 100 eV) astrophysically abundant (n(X)/n(H) greater than or equal to 10(exp -6)) elements. Included are approximately 74 lines in ions of O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, and Ni spanning a wavelength range of approximately 1 - 280 microns. We present new

  12. Warm absorbers in X-rays (WAX), a comprehensive high-resolution grating spectral study of a sample of Seyfert Galaxies - II. Warm absorber dynamics and feedback to galaxies

    NASA Astrophysics Data System (ADS)

    Laha, Sibasish; Guainazzi, Matteo; Chakravorty, Susmita; Dewangan, Gulab C.; Kembhavi, Ajit K.

    2016-04-01

    This paper is a sequel to the extensive study of warm absorber (WA) in X-rays carried out using high-resolution grating spectral data from XMM-Newton satellite (WAX-I). Here we discuss the global dynamical properties as well as the energetics of the WA components detected in the WAX sample. The slope of WA density profile (n ∝ r-α) estimated from the linear regression slope of ionization parameter ξ and column density NH in the WAX sample is α = 1.236 ± 0.034. We find that the WA clouds possibly originate as a result of photoionized evaporation from the inner edge of the torus (torus wind). They can also originate in the cooling front of the shock generated by faster accretion disc outflows, the ultrafast outflows, impinging on to the interstellar medium or the torus. The acceleration mechanism for the WA is complex and neither radiatively driven wind nor MHD-driven wind scenario alone can describe the outflow acceleration. However, we find that radiative forces play a significant role in accelerating the WA through the soft X-ray absorption lines, and also with dust opacity. Given the large uncertainties in the distance and volume filling factor estimates of the WA, we conclude that the kinetic luminosity ĖK of WA may sometimes be large enough to yield significant feedback to the host galaxy. We find that the lowest ionization states carry the maximum mass outflow, and the sources with higher Fe M UTA absorption (15-17 Å) have more mass outflow rates.

  13. The DEEP2 Galaxy Redshift Survey: AEGIS observations of a Dual AGNat z = 0.7

    SciTech Connect

    Gerke1, Brian F.; Newman, Jeffrey A.; Lotz, Jennifer; Yan,Renbin; Barmby, P.; Coil, Alison L.; Conselice, Christopher J.; Ivison,R.J.; Lin, Lihw ai; Koo, David C.; Nandra, Kirpal; Salim, Samir; Small,Todd; Weiner, Benjamin J.; Cooper, Michael C.; Davis, Marc; Faber, S.M.; Guhathakurta, Puragra

    2006-10-13

    We present evidence for a dual Active Galactic Nucleus (AGN) within an early-type galaxy at z = 0.709 in the Extended Groth Strip. The galaxy lies on the red sequence, with absolute magnitude M{sub B} = -21.0 ( AB, w , with h = 0 0.7) and rest-frame color U - B = 1.38. Its optical spectrum shows strong, double-peaked [O III] emission lines and weak H{beta} emission, with Seyfert-like line ratios. The two narrow peaks are separate by 630 km s-1 in velocity and arise from two distinct regions, spatially resolved in the DEIMOS spectrum, with a projected physical separation of 1.2 kpc. HST/ACS imaging shows an early-type (E/S0) galaxy with hints of disturbed structure, consistent with the remnant of a dissipationless merger. Multiwavelength photometric information from the AEGIS consortium confirm the identification of a dust-obscured AGN in an early-type galaxy, with detections in X-ray, optical, infrared and radio wavebands. These data are most readily explained as a single galaxy harboring two AGN--the first such system to be observed in an otherwise typical early-type galaxy.

  14. The Phoenix galaxy as seen by NuSTAR

    NASA Astrophysics Data System (ADS)

    Masini, A.; Comastri, A.; Puccetti, S.; Baloković, M.; Gandhi, P.; Guainazzi, M.; Bauer, F. E.; Boggs, S. E.; Boorman, P. G.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Farrah, D.; Hailey, C. J.; Harrison, F. A.; Koss, M. J.; LaMassa, S. M.; Ricci, C.; Stern, D.; Walton, D. J.; Zhang, W. W.

    2017-01-01

    Aims: We study the long-term variability of the well-known Seyfert 2 galaxy Mrk 1210 (also known as UGC 4203, or the Phoenix galaxy). Methods: The source was observed by many X-ray facilities in the last 20 yr. Here we present a NuSTAR observation and put the results in the context of previously published observations. Results: NuSTAR observed Mrk 1210 in 2012 for 15.4 ks. The source showed Compton-thin obscuration similar to that observed by Chandra, Suzaku, BeppoSAX and XMM-Newton over the past two decades, but different from the first observation by ASCA in 1995, in which the active nucleus was caught in a low flux state or was obscured by Compton-thick matter with a reflection-dominated spectrum. Thanks to the high-quality hard X-ray spectrum obtained with NuSTAR and exploiting the long-term spectral coverage spanning 16.9 yr, we can precisely disentangle the transmission and reflection components and put constraints on both the intrinsic long-term variability and hidden nucleus scenarios. In the former case, the distance between the reflector and the source must be at least 2 pc, while in the latter the eclipsing cloud may be identified with a water maser-emitting clump.

  15. Masas de agujeros negros en Narrow Line Seyfert 1

    NASA Astrophysics Data System (ADS)

    Schmidt, E.; Ferreiro, D.; Oio, G.; Vega, L.; Donoso, L.

    We describe two of the ways to estimate black hole masses in AGN, and then we estimate the black hole masses of 13 Narrow Line Seyfert 1 galaxies with the two methods: virial masses, using the correlation found by Greene & Ho (2005, ApJ, 630, 122); and the correlation found by Tremaine et al. (2002, ApJ, 574, 740). For this work we analyzed the optical spectroscopy data we obtained from CASLEO (San Juan). We compare the results obtained through both methods. FULL TEXT IN SPANISH

  16. Seyfert's Sextet (HGC 79): An Evolved Stephan's Quintet?

    NASA Astrophysics Data System (ADS)

    Durbala, A.; Sulentic, J.; Rosado, M.; Del Olmo, A.; Perea, J.; Plana, H.

    Scanning Fabry-Perot interferometers MOS/SIS (3.6m CFHT)+PUMA (2.1m OAN-SPM, México) and the long-slit spectrograph ALFOSC (2.5m NOT, La Palma) were used to measure the kinematics of gas and stars in Seyfert's Sextet (HCG79). We interpret it as a highly evolved group that formed from sequential acquistion of mostly late-type galaxies that are now slowly coalescing and undergoing strong secular evolution. We find evidence for possible feedback as revealed by accretion and minor merger events in two of the most evolved members.

  17. The exceptional X-ray variability of the dwarf Seyfert nucleus NGC 4395

    NASA Astrophysics Data System (ADS)

    Vaughan, S.; Iwasawa, K.; Fabian, A. C.; Hayashida, K.

    2005-01-01

    An analysis of the X-ray variability of the low-luminosity Seyfert nucleus NGC 4395, based on a long XMM-Newton observation, is presented. The power spectrum shows a clear break from a flat spectrum (α~ 1) to a steeper spectrum (α~ 2) at a frequency fbr= 0.5-3.0 × 10-3 Hz, comparable to the highest characteristic frequency found previously in a Seyfert galaxy. This extends the measured MBH-fbr values to lower MBH than previous studies of Seyfert galaxies, and is consistent with an inverse scaling of variability frequency with black hole mass. The variations observed are among the most violent seen in an active galactic nuclei to date, with the fractional rms amplitude (Fvar) exceeding 100 per cent in the softest band. The amplitude of the variations seems intrinsically higher in NGC 4395 than most other Seyfert galaxies, even after accounting for the differences in characteristic frequencies. The origin of this difference is not clear, but it is unlikely to be a high accretion rate (L/LEdd<~ 20 per cent for NGC 4395). The variations clearly follow the linear rms-flux relation, further supporting the idea that this is a ubiquitous characteristics of accreting black holes. The variations are highly coherent between different energy bands with any frequency-dependent time delay limited to <~1 per cent.

  18. The nature of the torus in the heavily obscured AGN Markarian 3: an X-ray study

    NASA Astrophysics Data System (ADS)

    Guainazzi, M.; Risaliti, G.; Awaki, H.; Arevalo, P.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Forster, K.; Hailey, C. J.; Harrison, F.; Koss, M.; Longinotti, A.; Markwardt, C.; Marinucci, A.; Matt, G.; Reynolds, C. S.; Ricci, C.; Stern, D.; Svoboda, J.; Walton, D.; Zhang, W.

    2016-08-01

    In this paper, we report the results of an X-ray monitoring campaign on the heavily obscured Seyfert galaxy, Markarian 3, carried out between the fall of 2014 and the spring of 2015 with NuSTAR, Suzaku and XMM-Newton. The hard X-ray spectrum of Markarian 3 is variable on all the time-scales probed by our campaign, down to a few days. The observed continuum variability is due to an intrinsically variable primary continuum seen in transmission through a large, but still Compton-thin column density (NH ˜ 0.8-1.1 × 1024 cm-2). If arranged in a spherical-toroidal geometry, the Compton scattering matter has an opening angle ≃66°, and is seen at a grazing angle through its upper rim (inclination angle ≃70°). We report a possible occultation event during the 2014 campaign. If the torus is constituted by a system of clouds sharing the same column density, this event allows us to constrain their number (17 ± 5) and individual column density, [≃ (4.9 ± 1.5) × 1022 cm-2]. The comparison of IR and X-ray spectroscopic results with state-of-the art `torus' models suggests that at least two-thirds of the X-ray obscuring gas volume might be located within the dust sublimation radius. We report also the discovery of an ionized absorber, characterized by variable resonant absorption lines due to He- and H-like iron. This discovery lends support to the idea that moderate column density absorbers could be due to clouds evaporated at the outer surface of the torus, possibly accelerated by the radiation pressure due to the central AGN emission leaking through the patchy absorber.

  19. Spectral molecular line surveys of active galaxies

    NASA Astrophysics Data System (ADS)

    Villicana Pedraza, Ilhuiyolitzin

    The enormous mass of molecular gas and dust found in the nuclei of active galaxies has a major role in feeding the activity (either starburst or AGN) and therefore in the galactic evolution. Thus, observations of the molecular can provide clues to identify and analyze the type of activity in very deeply obscured galactic nuclei. Indeed, studies of the chemical composition in starburst galaxies via wide band spectral has shown the potential of molecular spectroscopy to trace the physical and chemical propierties of their central ISM material. In this work we present the analysis of the emission of molecules such as HCN, CCH, CN,CS,HCO+, HNC, CH3OH, among others obtained from the survey of spectra of the 3 near seyfert galaxies observed with the APEX Telescope. We have also found that one of the molecules is not at LTE conditions- H3O+ molecule. Whether radiatively pumped or maser enhanced, the emission of H3O+ is emerging from a different region from most other molecules (distributed in two molecular lobes seen as the two velocity components). H3O+ emission peaks close to the systemic velocity of the system, particularly clear in NGC 253, which suggest the emission to be centrally peaked towards the nuclear engine, It is common in the same kind of galaxies? In adition, preliminar conclusions show isotopic ratio 12C/13C in starburst galaxies is higher than nuclei of the Milky Way indicating that interestelar matter in starburst nuclei is less processed than in the nucleus of the Milky Way .There are two possible explanations for this effect in starburst, nucleosynthesis differences due stellar population history and acretion of matter from halo.

  20. THE OFF-CENTERED SEYFERT-LIKE COMPACT EMISSION IN THE NUCLEAR REGION OF NGC 3621

    SciTech Connect

    Menezes, R. B.; Steiner, J. E.; Silva, Patricia da

    2016-02-01

    We analyze an optical data cube of the nuclear region of NGC 3621, taken with the integral field unit of the Gemini Multi-object Spectrograph. We found that the previously detected central line emission in this galaxy actually comes from a blob, located at a projected distance of 2.″14 ± 0.″08 (70.1 ± 2.6 pc) from the stellar nucleus. Only diffuse emission was detected in the rest of the field of view, with a deficit of emission at the position of the stellar nucleus. Diagnostic diagram analysis reveals that the off-centered emitting blob has a Seyfert 2 spectrum. We propose that the line-emitting blob may be a “fossil” emission-line region or a light “echo” from an active galactic nucleus (AGN), which was significantly brighter in the past. Our estimates indicate that the bolometric luminosity of the AGN must have decreased by a factor of ∼13–500 during the past ∼230 yr. A second scenario to explain the morphology of the line-emitting areas in the nuclear region of NGC 3621 involves no decrease of the AGN bolometric luminosity and establishes that the AGN is highly obscured toward the observer but not toward the line-emitting blob. The third scenario proposed here assumes that the off-centered line-emitting blob is a recoiling supermassive black hole, after the coalescence of two black holes. Finally, an additional hypothesis is that the central X-ray source is not an AGN, but an X-ray binary. This idea is consistent with all the scenarios we proposed.

  1. The nature of active galaxies

    NASA Astrophysics Data System (ADS)

    Chapman, Scott Christopher

    Many details of the structure of Active Galactic Nuclei (AGN) galaxies continue to elude researchers in the field. To shed light on some of the enigmas related to the fueling and classification of AGN, I have studied the core structure of a sample of 37 nearby Seyfert galaxies at high resolution using adaptive optics on the CFHT. This dataset consists of near-IR imaging from 1 to 3 μm (the J, H, and K bands). I first describe the instruments and observing techniques along with a presentation of the galaxy sample properties. I then outline the detailed data reduction and image processing required with adaptive optics observations, highlighting some of the associated unavoidable perils. A detailed multi-wavelength study is pursued for two nearby Seyfert galaxies, NGC3227 and NGC2992. With these objects, the current ideas of Seyfert fueling and unification of Seyfert types are scrutinized, focusing on the high spatial resolution achieved using adaptive optics in the near-IR. The dynamical processes and differing classifications of these galaxies are substantially clarified through their core morphologies. These studies show that scientific results can be established with AO data, in spite of the above mentioned artifact. For NGC2992, a spiral structure within the central 6' and a 1' extended feature are traced down to the core at the resolution of our images. We speculate, based on these observed structures, that multiple radio components are superposed which contribute to the observed figure-8 morphology in the VLA images: one associated with the spiral structure in the galaxy disk, and another flowing out of the galaxy plane. I then address whether the classification of Seyfert galaxy types can be explained via patchy dust at fairly large distances (~100 pc) from the central engine. Maps of dust extinction are constructed with the deep view afforded by the near-IR. These are compared with optical images observed with the Hubble Space Telescope (HST) to aid in

  2. RESOLVING THE BRIGHT HCN(1–0) EMISSION TOWARD THE SEYFERT 2 NUCLEUS OF M51: SHOCK ENHANCEMENT BY RADIO JETS AND WEAK MASING BY INFRARED PUMPING?

    SciTech Connect

    Matsushita, Satoki; Trung, Dinh-V-; Boone, Frédéric; Krips, Melanie; Lim, Jeremy; Muller, Sebastien

    2015-01-20

    We present high angular resolution observations of the HCN(1-0) emission (at ∼1'' or ∼34 pc), together with CO J = 1-0, 2-1, and 3-2 observations, toward the Seyfert 2 nucleus of M51 (NGC 5194). The overall HCN(1-0) distribution and kinematics are very similar to that of the CO lines, which have been indicated as the jet-entrained molecular gas in our past observations. In addition, high HCN(1-0)/CO(1-0) brightness temperature ratio of about unity is observed along the jets, similar to that observed at the shocked molecular gas in our Galaxy. These results strongly indicate that both diffuse and dense gases are entrained by the jets and outflowing from the active galactic nucleus. The channel map of HCN(1-0) at the systemic velocity shows a strong emission right at the nucleus, where no obvious emission has been detected in the CO lines. The HCN(1-0)/CO(1-0) brightness temperature ratio at this region reaches >2, a value that cannot be explained considering standard physical/chemical conditions. Based on our calculations, we suggest infrared pumping and possibly weak HCN masing, but still requiring an enhanced HCN abundance for the cause of this high ratio. This suggests the presence of a compact dense obscuring molecular gas in front of the nucleus of M51, which remains unresolved at our ∼1'' (∼34 pc) resolution, and consistent with the Seyfert 2 classification picture.

  3. Sensitive radio survey of obscured quasar candidates

    NASA Astrophysics Data System (ADS)

    Alexandroff, Rachael M.; Zakamska, Nadia L.; van Velzen, Sjoert; Greene, Jenny E.; Strauss, Michael A.

    2016-12-01

    We study the radio properties of moderately obscured quasars in samples at both low (z ˜ 0.5) and high (z ˜ 2.5) redshift to understand the role of radio activity in accretion, using the Karl G. Jansky Very Large Array (VLA) at 6.0 GHz and 1.4 GHz. Our z ˜ 2.5 sample consists of optically selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of νLν[1.4 GHz] ≲ 1040 erg s-1. Only a single source is individually detected in our deep (rms˜10 μJy) exposures. This population would not be identified by radio-based selection methods used for distinguishing dusty star-forming galaxies and obscured active nuclei. In our pilot A-array study of z ˜ 0.5 radio-quiet quasars, we spatially resolve four of five objects on scales ˜5 kpc and find they have steep spectral indices with an average value of α = -0.75. Therefore, radio emission in these sources could be due to jet-driven or radiatively driven bubbles interacting with interstellar material on the scale of the host galaxy. Finally, we also study the additional population of ˜200 faint ( ˜ 40 μJy-40 mJy) field radio sources observed over ˜120 arcmin2 of our data. 60 per cent of these detections (excluding our original targets) are matched in the Sloan Digital Sky Survey (SDSS) and/or Wide-Field Infrared Survey Explorer (WISE) and are, in roughly equal shares, active galactic nuclei (AGN) at a broad range of redshifts, passive galaxies with no other signs of nuclear activity and infrared-bright but optically faint sources. Spectroscopically or photometrically confirmed star-forming galaxies constitute only a small minority of the matches. Such sensitive radio surveys allow us to address important questions of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.

  4. The Seyfert II nature of the IRAS source FSC 10214+4724

    NASA Technical Reports Server (NTRS)

    Elston, Richard; Mccarthy, Patrick J.; Eisenhardt, Peter; Dickinson, Mark; Spinrad, Hyron; Januzzi, Buell T.; Maloney, Philip

    1994-01-01

    We have observed the rest-frame optical and UV spectra of the luminous, high redshift Infrared Astronomy Satellite (IRAS) source FSC 10214+4724. We find the optical emission lines to be characterized by ratios similar to those found in Seyfert II galaxies. We support the conclusion of previous work that the UV emission lines are similar to those attributed to Active Galactic Nuclei (AGN) rather than to star formation. The ratio H alpha/H beta greater than or equal to 20 (2 sigma lower limit) implies substantial reddening of the narrow line region with A(sub V) greater than 5.5, sufficient to hide a broad line region in our H alpha observations. Given this large inferred reddening and the strength of the UV continuum and emission lines, we conclude (as have others) that simple screen models of reddening are not appropriate for this object. These properties are very similar to those of the infrared luminous galaxies at lower redshift, suggesting that FSC 10244+4724 is the luminous extreme of the same population. We also present H band (1.6 micrometer) imaging polarimetry observations and find that the rest-frame optical emission is unpolarized (P = 3.2% +/- 22.0%). This deep image of the field shows FSC 10214+4724 to possess an unresolved core, with several companions located within 10 sec of the point source. We find it unlikely that this group of objects is physically associated with FSC 10214+4724 at z = 2.3, and we argue that their magnitudes and colors are more consistant with those expected with those expected for galaxies in a foreground group. While galaxy number counts would suggest that such a projection has a low probability of being observed randomly, a foreground group might gravitational lens the z = 2.3 source, making such random statistics inappropriate, and contribute to the large observed luminosity of FSC 10214+4724. Comparison of H band images taken on two occasions one year apart show that FSC 10214+4724 had varied by 0.16 +/- 0.03 mag relative

  5. The evolution of obscured AGN

    NASA Astrophysics Data System (ADS)

    Brightman, Murray

    2012-09-01

    We present results on the evolution of Compton thick AGN with redshift, and the nature of this obscuration, important for understanding the accretion history of the universe and for AGN unification schemes. We use lessons learned from spectral complexity of local AGN (Brightman & Nandra 2012) and up to date spectral models of heavily absorbed AGN, which take into account Compton scattering, self consistent Fe Ka modeling and the geometry of the circumnuclear material (Brightman & Nandra 2011), to optimise our identification of Compton thick AGN and understanding of the obscuring material. Results from the Chandra Deep Field South are presented (Brightman & Ueda, 2012), which show an increasing fraction of CTAGN with redshift and that most heavily obscured AGN are geometrically deeply buried in material, as well as new results from and extension of this study to AEGIS-XD and Chandra-COSMOS survey, which aim to fully characterise the dependence of heavy AGN obscuration on redshift and luminosity.

  6. Characterizing the redshifts and luminosities of WISE selected obscured AGN using SALT optical spectra.

    NASA Astrophysics Data System (ADS)

    Hviding, Raphael E.; Hickox, Ryan C.; Hainline, Kevin N.; Carroll, Christopher M.; DiPompeo, Mike A.; Jones, Mackenzie L.

    2016-08-01

    We present the results of several optical spectroscopic surveys covering over 100 candidate luminous obscured active galactic nuclei (AGN) identified by their mid-infrared emission detected with the Wide-Field Infrared Survey Explorer (WISE). These galaxies were selected based on red WISE colors and galaxy-like optical emission, and were studied using long-slit optical spectroscopy with the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT). Our spectra were analyzed to obtain redshifts and emission line flux ratios for each galaxy. These results verify that WISE is an effective section method for luminous obscured AGN, allow for the characterization of redshifts and luminosities of the WISE color selected obscured AGN population, and could potentially contribute to large statistical studies of obscured AGN distributions in the future.

  7. Announcment: Conference on Obscured AGN Across Cosmic Time

    NASA Astrophysics Data System (ADS)

    2006-12-01

    Current deep surveys, notably in X-rays and the mid-IR, are making it possible to carry out a census of essentially all the luminous AGN in the Universe. By pene-trating the obscuration that, in Type 2 sources, hides the nuclear regions in the UV to the near-IR spectrum, these new surveys are finding the radio quiet coun-terparts of the powerful radio galaxies.

  8. Extending virial black hole mass estimates to low-luminosity or obscured AGN: the cases of NGC 4395 and MCG -01-24-012

    NASA Astrophysics Data System (ADS)

    La Franca, F.; Onori, F.; Ricci, F.; Sani, E.; Brusa, M.; Maiolino, R.; Bianchi, S.; Bongiorno, A.; Fiore, F.; Marconi, A.; Vignali, C.

    2015-05-01

    In the last decade, using single epoch (SE) virial based spectroscopic optical observations, it has been possible to measure the black hole (BH) mass on large type 1 active galactic nuclei (AGN) samples. However this kind of measurements cannot be applied on those obscured type 2 and/or low-luminosity AGN where the nuclear component does not dominate in the optical. We have derived new SE relationships, based on the full width at half-maximum and luminosity of the broad-line region component of the Paβ emission line and/or the hard X-ray luminosity in the 14-195 keV band, which have the prospect of better working with low luminosity or obscured AGN. The SE relationships have been calibrated in the 105-109 M⊙ mass range, using a sample of AGN, whose BH masses have been previously measured using reverberation mapping techniques. Our tightest relationship between the reverberation-based BH mass and the SE virial product has an intrinsic spread of 0.20 dex. Thanks to these SE relations, in agreement with previous estimates, we have measured a BH mass of M_BH = 1.7^{+1.3}_{-0.7} × 10^5 M⊙ for the low luminosity, type 1, AGN NGC 4395 (one of the smallest active galactic BH known). We also measured, for the first time, a BH mass of M_BH = 1.5^{+1.1}_{-0.6} × 10^7 M⊙ for the Seyfert 2 galaxy MCG -01-24-012.

  9. Galaxy interactions and strength of nuclear activity

    NASA Technical Reports Server (NTRS)

    Simkin, S. M.

    1990-01-01

    Analysis of data in the literature for differential velocities and projected separations of nearby Seyfert galaxies with possible companions shows a clear difference in projected separations between type 1's and type 2's. This kinematic difference between the two activity classes reinforces other independent evidence that their different nuclear characteristics are related to a non-nuclear physical distinction between the two classes. The differential velocities and projected separations of the galaxy pairs in this sample yield mean galaxy masses, sizes, and mass to light ratios which are consistent with those found by the statistical methods of Karachentsev. Although the galaxy sample discussed here is too small and too poorly defined to provide robust support for these conclusions, the results strongly suggest that nuclear activity in Seyfert galaxies is associated with gravitational perturbations from companion galaxies, and that there are physical distinctions between the host companions of Seyfert 1 and Seyfert 2 nuclei which may depend both on the environment and the structure of the host galaxy itself.

  10. What Powers the 12 μm Luminosities in AGNs: Spitzer/IRS Spectroscopic Study of the 12 μm Seyfert Sample

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Huang, J.; Charmandaris, V.

    2009-10-01

    We present a mid-IR study of the 12 μm Seyfert sample, using 5-35 μm low-resolution spectroscopy from Spitzer/IRS. Sources in this sample display a wide variety of spectral shapes. We perform an analysis of the continuum emission, the strength of the Polycyclic Aromatic Hydrocarbon (PAH) emission, as well as fine-structure lines, in order to study the mid-IR properties of the local Seyfert galaxies. We find that the equivalent widths of PAHs decrease with increasing dust temperature. We also propose a method to estimate the AGN contribution to the integrated 12 μm emission of the galaxy.

  11. THE SPITZER MID-INFRARED ACTIVE GALACTIC NUCLEUS SURVEY. I. OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF OBSCURED CANDIDATES AND NORMAL ACTIVE GALACTIC NUCLEI SELECTED IN THE MID-INFRARED

    SciTech Connect

    Lacy, M.; Ridgway, S. E.; Gates, E. L.; Petric, A. O.; Sajina, A.; Urrutia, T.; Cox Drews, S.; Harrison, C.; Seymour, N.; Storrie-Lombardi, L. J.

    2013-10-01

    We present the results of a program of optical and near-infrared spectroscopic follow-up of candidate active galactic nuclei (AGNs) selected in the mid-infrared. This survey selects both normal and obscured AGNs closely matched in luminosity across a wide range, from Seyfert galaxies with bolometric luminosities L {sub bol} ∼ 10{sup 10} L {sub ☉} to highly luminous quasars (L {sub bol} ∼ 10{sup 14} L {sub ☉}), all with redshifts ranging from 0 to 4.3. Samples of candidate AGNs were selected with mid-infrared color cuts at several different 24 μm flux density limits to ensure a range of luminosities at a given redshift. The survey consists of 786 candidate AGNs and quasars, of which 672 have spectroscopic redshifts and classifications. Of these, 137 (20%) are type 1 AGNs with blue continua, 294 (44%) are type 2 objects with extinctions A{sub V} ∼> 5 toward their AGNs, 96 (14%) are AGNs with lower extinctions (A{sub V} ∼ 1), and 145 (22%) have redshifts, but no clear signs of AGN activity in their spectra. Of the survey objects 50% have L {sub bol} > 10{sup 12} L {sub ☉}, in the quasar regime. We present composite spectra for type 2 quasars and objects with no signs of AGN activity in their spectra. We also discuss the mid-infrared—emission-line luminosity correlation and present the results of cross correlations with serendipitous X-ray and radio sources. The results show that: (1) obscured objects dominate the overall AGN population, (2) mid-infrared selected AGN candidates exist which lack AGN signatures in their optical spectra but have AGN-like X-ray or radio counterparts, and (3) X-ray and optical classifications of obscured and unobscured AGNs often differ.

  12. Uncovering the Spectral Energy Distribution in Active Galaxies Using High Ionization Mid-Infrared Emission Lines

    NASA Technical Reports Server (NTRS)

    Melendez, M.; Kraemer, S. B.; Weaver, K. A.; Mushotzky, R. F.

    2011-01-01

    The shape of the spectral energy distribution of active galaxies in the EUV soft X-ray band (13.6 eV to 1 keV) is uncertain because obscuration by dust and gas can hamper our view of the continuum. To investigate the shape of the spectral energy distribution in this energy band, we have generated a set of photoionization models which reproduce the small dispersion found in correlations between high-ionization mid-infrared emission lines in a sample of hard X-ray selected AGN. Our calculations show that a broken power-law continuum model is sufficient to reproduce the [Ne V]14.32 microns/[Ne III], [Ne V]24.32 microns/[O IV]25.89 micron and [O IV] 25.89 microns/[Ne III] ratios, and does not require the addition of a "big bump" EUV model component. We constrain the EUV-soft X-ray slope, alpha(sub i), to be between 1.5 - 2.0 and derive a best fit of alpha(sub i) approx. 1.9 for Seyfert 1 galaxies, consistent with previous studies of intermediate redshift quasars. If we assume a blue bump model, most sources in our sample have derived temperatures between T(sub BB) = 10(exp 5.18) K to 10(exp 5.7) K, suggesting that the peak of this component spans a large range of energies extending from approx. (Lambda)600 A to > (Lambda)1900 A. In this case, the best fitting peak energy that matches the mid-infrared line ratios of Seyfert 1 galaxies occurs between approx. (Lambda)700-(Lambda)1000 A. Despite the fact that our results do not rule out the presence of an EUV bump, we conclude that our power-law model produces enough photons with energies > 4 Ry to generate the observed amount of mid-infrared emission in our sample of BAT AGN.

  13. Using HUBBLE SPACE TELESCOPE Imaging of Nuclear Dust Morphology to Rule Out Bars Fueling Seyfert Nuclei

    NASA Astrophysics Data System (ADS)

    Regan, Michael W.; Mulchaey, John S.

    1999-06-01

    If active galactic nuclei (AGN) are powered by the accretion of matter onto massive black holes, how does the gas in the host galaxy lose the required angular momentum to approach the black hole? Gas easily transfers angular momentum to stars in strong bars, making them likely candidates. Although ground-based searches for bars in active galaxies using both optical and near-infrared surface brightness have not found any excess of bars relative to quiescent galaxies, the searches have not been able to rule out small-scale nuclear bars. To look for these nuclear bars we use Hubble Space Telescope Wide Field and Planetary Camera 2 and Near Infrared Camera and Multi-Object Spectrometer color maps to search for the straight dust lane signature of strong bars. Of the twelve Seyfert galaxies in our sample, only three have dust lanes consistent with a strong nuclear bar. Therefore, strong nuclear bars cannot be the primary fueling mechanism for Seyfert nuclei. We do find that a majority of the galaxies show an spiral morphology in their dust lanes. These spiral arms may be a possible fueling mechanism.

  14. Galaxies et trous noirs supermassifs

    NASA Astrophysics Data System (ADS)

    Collin-Zahn, Suzy

    2016-08-01

    A few percents of galaxies are classified as « active ». An active galaxy is a galaxy whose nucleus emits more energy than the whole galaxy in the form of electromagnetic radiation, relativistic particles, or mechanical energy. It is activated by a supermassive black hole fueled by matter falling on it, whose characteristics (Eddington luminosity, spin) are recalled. The class includes quasars and Seyfert galaxies. All massive "non active" galaxies contain a supermassive black hole, but there is not enough matter in its environment so as the nucleus becomes luminous. Different items are considered in the paper : how supermassive black holes are fueled, the accretion disc, the jets and the winds, the unified model of active galaxies, how are determined the masses of supermassive black holes, and what is the relation between the evolution of galaxies and supermassive black holes.

  15. High-Resolution Imaging in 3-mm and 0.8-mm Bands and Abundances of Shock/Dust Related Molecules Toward the Seyfert Galaxy NGC 1068 Observed with ALMA

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    We present the results of high-angular-resolution in 3-mm and 0.8-mm band observations with ALMA in cycle-0 toward one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068. The physical properties of CO isotopic species, CS, CN, and shock and dust related molecules such as HNCO, CH3CN, SO, and CH3OH were estimated using rotation diagrams. We discuss the chemistry of each species, and compare the fractional abundances in the circumnuclear disk (CND) and starburst ring with those of Galactic sources in order to study the overall characteristics.

  16. The most obscured AGN in the COSMOS field

    NASA Astrophysics Data System (ADS)

    Lanzuisi, G.; Perna, M.; Delvecchio, I.; Berta, S.; Brusa, M.; Cappelluti, N.; Comastri, A.; Gilli, R.; Gruppioni, C.; Mignoli, M.; Pozzi, F.; Vietri, G.; Vignali, C.; Zamorani, G.

    2015-06-01

    Highly obscured active galactic nuclei (AGN) are common in nearby galaxies, but are difficult to observe beyond the local Universe, where they are expected to significantly contribute to the black hole accretion rate density. Furthermore, Compton-thick (CT) absorbers (NH ≳ 1024 cm-2) suppress even the hard X-ray (2-10 keV) AGN nuclear emission, and therefore the column density distribution above 1024 cm-2 is largely unknown. We present the identification and multi-wavelength properties of a heavily obscured (NH ≳ 1025 cm-2), intrinsically luminous (L2-10 > 1044 erg s-1) AGN at z = 0.353 in the COSMOS field. Several independent indicators, such as the shape of the X-ray spectrum, the decomposition of the spectral energy distribution and X-ray/[NeV] and X-ray/6 μm luminosity ratios, agree on the fact that the nuclear emission must be suppressed by a ≳1025 cm-2 column density. The host galaxy properties show that this highly obscured AGN is hosted in a massive star-forming galaxy, showing a barred morphology, which is known to correlate with the presence of CT absorbers. Finally, asymmetric and blueshifted components in several optical high-ionization emission lines indicate the presence of a galactic outflow, possibly driven by the intense AGN activity (LBol/LEdd = 0.3-0.5). Such highly obscured, highly accreting AGN are intrinsically very rare at low redshift, whereas they are expected to be much more common at the peak of the star formation and BH accretion history, at z ~ 2-3. We demonstrate that a fully multi-wavelength approach can recover a sizable sample of such peculiar sources in large and deep surveys such as COSMOS.

  17. New southern galaxies with active nuclei

    SciTech Connect

    Maia, M.A.G.; Da costa, L.N.; Willmer, C.; Pellegrini, P.S.; Rite, C.

    1987-03-01

    A list of AGN candidates, identified from optical spectra taken as part of an ongoing redshift survey of southern galaxies, is presented. The identification, coordinates, morphological type, measured heliocentric radial velocity, and proposed emission type are given for the galaxies showing evidence of nonstellar nuclear activity. Using standard diagnostics, several new Seyferts and low-ionization nuclear-emission regions (LINERs) are identified among the emission-line galaxies observed. 14 references.

  18. A NuSTAR SURVEY OF NEARBY ULTRALUMINOUS INFRARED GALAXIES

    SciTech Connect

    Teng, Stacy H.; Rigby, Jane R.; Ptak, Andrew; Stern, Daniel; Alexander, D. M.; Bauer, Franz E.; Boggs, Stephen E.; Craig, William W.; Brandt, W. Niel; Luo, Bin; Christensen, Finn E.; Comastri, Andrea; Farrah, Duncan; Gandhi, Poshak; Hailey, Charles J.; Harrison, Fiona A.; Hickox, Ryan C.; Koss, Michael; and others

    2015-11-20

    We present a Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton survey of nine of the nearest ultraluminous infrared galaxies (ULIRGs). The unprecedented sensitivity of NuSTAR at energies above 10 keV enables spectral modeling with far better precision than was previously possible. Six of the nine sources observed were detected sufficiently well by NuSTAR to model in detail their broadband X-ray spectra, and recover the levels of obscuration and intrinsic X-ray luminosities. Only one source (IRAS 13120–5453) has a spectrum consistent with a Compton-thick active galactic nucleus (AGN), but we cannot rule out that a second source (Arp 220) harbors an extremely highly obscured AGN as well. Variability in column density (reduction by a factor of a few compared to older observations) is seen in IRAS 05189–2524 and Mrk 273, altering the classification of these borderline sources from Compton-thick to Compton-thin. The ULIRGs in our sample have surprisingly low observed fluxes in high-energy (>10 keV) X-rays, especially compared to their bolometric luminosities. They have lower ratios of unabsorbed 2–10 keV to bolometric luminosity, and unabsorbed 2–10 keV to mid-IR [O iv] line luminosity than do Seyfert 1 galaxies. We identify IRAS 08572+3915 as another candidate intrinsically X-ray weak source, similar to Mrk 231. We speculate that the X-ray weakness of IRAS 08572+3915 is related to its powerful outflow observed at other wavelengths.

  19. Spectral Energy Distribution of Star-Forming Galaxies

    NASA Technical Reports Server (NTRS)

    Kinney, A. L.

    1997-01-01

    Our analysis allowed us to address the following points: 1) the nature of the featureless ultraviolet continuum in Seyfert 2's, in particular the amount of stellar population that contributes to this waveband; 2) the difference between Seyfert l's and Seyfert 2's in the ratio of ultraviolet (lambda)1400A to soft X-rays continuum, which is larger in Seyfert 2's and apparently contradicts the Unified Model, but may be resolved if we consider the stellar population; 3) search for anisotropic radiation escaping from the nucleus of Seyfert 2's, by comparing the number of ionizing photons, estimated from the ultraviolet continuum photons, to the number of recombination photons, calculated using the H(beta) line flux. In addition, the research from this grant produced template spectra that have been used in a wide variety of applications, including the identification of high redshift galaxies in the Slone survey.

  20. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  1. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  2. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  3. 27 CFR 19.346 - Determining obscuration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... water may be added to a lot of spirits to be bottled for which the determination of proof obscuration is... chapter, the proof obscuration of spirits to be bottled on the basis of a representative sample taken...

  4. Optical Spectroscopy of Luminous Infrared Galaxies. II. Analysis of the Nuclear and Long-Slit Data

    NASA Astrophysics Data System (ADS)

    Veilleux, S.; Kim, D.-C.; Sanders, D. B.; Mazzarella, J. M.; Soifer, B. T.

    1995-05-01

    A spectroscopic survey of a sample of 200 luminous IRAS galaxies (LIGs: L_ir_^7^ > 3 x 10^10^ L_sun_; H_0_ = 75 km s^-1^ Mpc^-1^) was carried out using the Palomar 5 meter and University of Hawaii 2.2 m telescopes. Kim et al. (1995) described the data-taking and data-reduction procedures and presented line and continuum measurements extracted from the nucleus of these objects. In this paper, the nuclear data are combined with circumnuclear measurements on 23 of these galaxies to investigate the properties of the line-emitting gas and underlying stellar population in and out of the nucleus. The nuclear spectra of these galaxies were classified as H II region-like" or "AGN-like" using a large number of line-ratio diagnostics corrected for the underlying stellar absorption features. This correction is an important source of errors in some previous studies. The emission-line spectra of many AGNs were found to-be of relatively low ionization level and were therefore classified as LINER. We confirm that both the fraction of LIGs with AGN spectra and the fraction of Seyferts among the AGN increase with infrared luminosity, reaching values of 62% and 54% at the highest observed luminosities, respectively. The fraction of LINERs, on the other hand, is relatively constant at ~27%. The source of the ionization of the emission-line gas often is a function of the distance from the nucleus. Based on the emission-line ratios and the strengths of the stellar absorption features, circumnuclear starburst activity is a common feature of LIGs, regardless of their nuclear spectral types. The emission-line, absorption-line, continuum, radio, and IRAS properties of the LINERs suggest that most of the LINER emission in these infrared-selected galaxies is produced through shock ionization rather than photoionization by a genuine active nucleus. The nuclear region of Seyfert LIGs is found to be slightly less reddened than that of the LINERs and H II galaxies. The dust distribution generally

  5. A SPECTACULAR OUTFLOW IN AN OBSCURED QUASAR

    SciTech Connect

    Greene, Jenny E.; Zakamska, Nadia L.; Smith, Paul S.

    2012-02-10

    SDSS J1356+1026 is a pair of interacting galaxies at redshift z = 0.123 that hosts a luminous obscured quasar in its northern nucleus. Here we present two long-slit Magellan LDSS-3 spectra that reveal a pair of symmetric {approx}10 kpc size outflows emerging from this nucleus, with observed expansion velocities of {approx}250 km s{sup -1} in projection. We present a kinematic model of these outflows and argue that the deprojected physical velocities of expansion are likely {approx}1000 km s{sup -1} and that the kinetic energy of the expanding shells is likely 10{sup 44-45} erg s{sup -1}, with an absolute minimum of >10{sup 42} erg s{sup -1}. Although a radio counterpart is detected at 1.4 GHz, it is faint enough that the quasar is considered to be radio quiet by all standard criteria, and there is no evidence of extended emission due to radio lobes, whether aged or continuously powered by an ongoing jet. We argue that the likely level of star formation is insufficient to power the observed energetic outflow and that SDSS J1356+1026 is a good case for radio-quiet quasar feedback. In further support of this hypothesis, polarimetric observations show that the direction of quasar illumination is coincident with the direction of the outflow.

  6. MODELING MID-INFRARED DIAGNOSTICS OF OBSCURED QUASARS AND STARBURSTS

    SciTech Connect

    Snyder, Gregory F.; Jonsson, Patrik; Hernquist, Lars; Hayward, Christopher C.; Sajina, Anna; Cox, Thomas J.; Hopkins, Philip F.; Yan Lin

    2013-05-10

    We analyze the link between active galactic nuclei (AGNs) and mid-infrared flux using dust radiative transfer calculations of starbursts realized in hydrodynamical simulations. Focusing on the effects of galaxy dust, we evaluate diagnostics commonly used to disentangle AGN and star formation in ultraluminous infrared galaxies (ULIRGs). We examine these quantities as a function of time, viewing angle, dust model, AGN spectrum, and AGN strength in merger simulations representing two possible extremes of the ULIRG population: one is a typical gas-rich merger at z {approx} 0, and the other is characteristic of extremely obscured starbursts at z {approx} 2-4. This highly obscured burst begins star-formation-dominated with significant polycyclic aromatic hydrocarbon (PAH) emission, and ends with a {approx}10{sup 9} yr period of red near-IR colors. At coalescence, when the AGN is most luminous, dust obscures the near-infrared AGN signature, reduces the relative emission from PAHs, and enhances the 9.7 {mu}m absorption by silicate grains. Although generally consistent with previous interpretations, our results imply none of these indicators can unambiguously estimate the AGN luminosity fraction in all cases. Motivated by the simulations, we show that a combination of the extinction feature at 9.7 {mu}m, the PAH strength, and a near-infrared slope can simultaneously constrain the AGN fraction and dust grain distribution for a wide range of obscuration. We find that this indicator, accessible to the James Webb Space Telescope, may estimate the AGN power as tightly as the hard X-ray flux alone, thereby providing a valuable future cross-check and constraint for large samples of distant ULIRGs.

  7. Modeling Mid-infrared Diagnostics of Obscured Quasars and Starbursts

    NASA Astrophysics Data System (ADS)

    Snyder, Gregory F.; Hayward, Christopher C.; Sajina, Anna; Jonsson, Patrik; Cox, Thomas J.; Hernquist, Lars; Hopkins, Philip F.; Yan, Lin

    2013-05-01

    We analyze the link between active galactic nuclei (AGNs) and mid-infrared flux using dust radiative transfer calculations of starbursts realized in hydrodynamical simulations. Focusing on the effects of galaxy dust, we evaluate diagnostics commonly used to disentangle AGN and star formation in ultraluminous infrared galaxies (ULIRGs). We examine these quantities as a function of time, viewing angle, dust model, AGN spectrum, and AGN strength in merger simulations representing two possible extremes of the ULIRG population: one is a typical gas-rich merger at z ~ 0, and the other is characteristic of extremely obscured starbursts at z ~ 2-4. This highly obscured burst begins star-formation-dominated with significant polycyclic aromatic hydrocarbon (PAH) emission, and ends with a ~109 yr period of red near-IR colors. At coalescence, when the AGN is most luminous, dust obscures the near-infrared AGN signature, reduces the relative emission from PAHs, and enhances the 9.7 μm absorption by silicate grains. Although generally consistent with previous interpretations, our results imply none of these indicators can unambiguously estimate the AGN luminosity fraction in all cases. Motivated by the simulations, we show that a combination of the extinction feature at 9.7 μm, the PAH strength, and a near-infrared slope can simultaneously constrain the AGN fraction and dust grain distribution for a wide range of obscuration. We find that this indicator, accessible to the James Webb Space Telescope, may estimate the AGN power as tightly as the hard X-ray flux alone, thereby providing a valuable future cross-check and constraint for large samples of distant ULIRGs.

  8. THE INVESTIGATION OF OBSCURE DEATHS.

    PubMed

    SIMPSON, K

    1964-10-17

    Unexpected death from obscure causes places a responsibility on the coroner which is delegated to the police, the pathologist and the laboratory. Important insurance and civil litigation issues may be at stake and crime must not be overlooked. This article stresses the importance of (a) powers of observation, (b) awareness of possibilities, (c) a flexible mind and (d) competence in forensic pathology. Cases quoted and illustrated show mistakes which have caused error-and injustice.The importance of discussion with clinical colleagues is emphasized; painstaking autopsy and meticulous laboratory examinations are vital. Poisoning is particularly easily overlooked.

  9. X-ray View of Four High-Luminosity Swift-BAT AGN: Unveiling Obscuration and Reflection with Suzaku

    NASA Technical Reports Server (NTRS)

    Fiorettil, V.; Angelini, L.; Mushotzky, R. F.; Koss, M.; Malaguti, G.

    2013-01-01

    Aims. A complete census of obscured Active Galactic Nuclei (AGN) is necessary to reveal the history of the super massive black hole (SMBH) growth and galaxy evolution in the Universe given the complex feedback processes and the fact that much of this growth occurs in an obscured phase. In this context, hard X-ray surveys and dedicated follow-up observations represent a unique tool for selecting highly absorbed AGN and for characterizing the obscuring matter surrounding the SMBH. Here we focus on the absorption and reflection occurring in highly luminous, quasar-like AGN, to study the relation between the geometry of the absorbing matter and the AGN nature (e.g. X-ray, optical, and radio properties), and to help to determine the column density dependency on the AGN luminosity. Methods. The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray BAT fluxes in excess of 10(exp -11) erg per square centimeter and an average redshift of 0.03. Among them, four of the most luminous BAT AGN (44.73 less than LogLBAT less than 45.31) were selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452), J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density, scattered/reflected emission, the properties of the Fe K line, and a possible variability are fully analyzed. For the latter, the spectral properties from Chandra, XMM-Newton and Swift/XRT public observations were compared with the present Suzaku analysis, adding an original spectral analysis when non was available from the literature. Results. Of our sample, 3C 452 is the only certain Compton-thick AGN candidate because of i) the high absorption (N(sub H) approximately 4 × 10(exp 23) per square centimeter) and strong Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e. the low scattering fraction (less than 0.5%) and the extremely low relative [OIII] luminosity. In contrast 3C 105 is not reflection-dominated, despite the comparable column density

  10. Flamingos 2 Spectroscopy of Obscured and Unobscured Quasars

    NASA Astrophysics Data System (ADS)

    Ridgway, Susan; Lacy, Mark; Urrutia, Tanya; Petric, Andreea

    2013-08-01

    We will use Flamingos-2 to obtain spectra of luminous AGN and quasars selected in the mid-infrared. Mid-infrared selection is much less biased with respect to obscuration than optical and X-ray techniques, and hence allows for finding obscured (Type-2) quasars as well as Type-1 quasars. Our survey so far has been very successful and has provided an unique opportunity to construct luminosity functions for both Type-1 and Type-2 quasars selected in the same way and covering similar redshifts and luminosities. We have quantifed the change in the obscured fraction with luminosity and redshift for the first time, and find interesting indications that at high redshift the obscured fraction rises, consistent with models for the joint formation of the galaxy and black hole populations. Our samples are, however, still quite incomplete at low fluxes (and therefore lower luminosities at a given redshift), particularly in the southern hemisphere. Near-infrared spectroscopy, such as that we have previously obtained with NIRI at Gemini N, offers us the best possibility of bringing these southern samples to a reasonable completeness level, and will greatly increase the number of high z quasars in our sample. This will allow us to better judge our tantalizing initial results on the redshift evolution of the obscured fraction. In addition, these southern targets can be followed up with ALMA and GEMS/GSAOI to study the morphologies and star-formation properties of the hosts, allowing further exploration of the relationship between the formation of massive bulges and supermassive blackholes in the early universe.

  11. Espectroscopía infrarroja de la galaxia Seyfert NGC6300

    NASA Astrophysics Data System (ADS)

    Gaspar, G.; D‘Ambra, A.; Díaz, R. J.; Gunthardt, G.; Gómez, P.

    2015-08-01

    Here we present a spectroscopic study in the near infrared band of the active galaxy NGC 6300, with spectra obtained with the spectrograph Flamingos 2 of the telescope Gemini South. The spectra were taken in the range 1 to 2.4 mm, with a mean spatial resolution of 0.6'', in this work we present preliminary results for a single band, . This global study is based in the analysis of the relative contributions in the emission of the Seyfert nuclei and the circunnuclear star formation to discuss later the role of the AGN in the scenarios of dynamical evolution of galaxies. We present the detection of a broad component in the Pa emission line, an unexpected feature in this galaxy so far classified as a 2 type.

  12. The environments of Markarian galaxies

    NASA Technical Reports Server (NTRS)

    Mackenty, John W.; Simpson, Caroline; Mclean, Brian

    1990-01-01

    The extensively studied Markarian sample of 1500 ultraviolet excess galaxies contains many Seyfert, starburst, and peculiar galaxies. Using the 20 minute V plates obtained for the construction of the Hubble Space Telescope Guide Star Catalog, the authors investigated the morphologies of the Markarian galaxies and the environments in which they are located. The relationship between the types of nuclear activity and the morphologies and environments of the Markarian galaxies is discussed. The authors conclude that the type of nuclear activity present in the galaxies of the Markarian sample is not dependent on either the morphology or the local environment of the galaxy. This is not to imply that nuclear activity per se is not influenced by the environment in which the nucleus is located. Rather the type of nuclear activity (at least in the Markarian population) does not appear to be determined by the environment.

  13. The Angular Clustering of WISE-Selected AGN: Different Haloes for Obscured and Unobscured AGN

    NASA Astrophysics Data System (ADS)

    Yan, Lin

    2015-08-01

    We calculate the angular correlation function for a sample of 170,000 AGN extracted from the Wide-field Infrared Survey Explorer (WISE) catalog, selected to have red mid-IR colors (W1 - W2 > 0.8) and 4.6 micron flux densities brighter than 0.14 mJy). The sample is expected to be >90% reliable at identifying AGN, and to have a mean redshift of z=1.1. In total, the angular clustering of WISE-AGN is roughly similar to that of optical AGN. We cross-match these objects with the photometric SDSS catalog and distinguish obscured sources with (r - W2) > 6 from bluer, unobscured AGN. Obscured sources present a higher clustering signal than unobscured sources. Since the host galaxy morphologies of obscured AGN are not typical red sequence elliptical galaxies and show disks in many cases, it is unlikely that the increased clustering strength of the obscured population is driven by a host galaxy segregation bias. By using relatively complete redshift distributions from the COSMOS survey, we find obscured sources at mean redshift z=0.9 have a bias of b = 2.9 \\pm 0.6 and are hosted in dark matter halos with a typical mass of log(M/M_odot)~13.5. In contrast, unobscured AGN at z~1.1 have a bias of b = 1.6 \\pm 0.6 and inhabit halos of log(M/M_odot)~12.4. These findings suggest that obscured AGN inhabit denser environments than unobscured AGN, and are difficult to reconcile with the simplest AGN unification models, where obscuration is driven solely by orientation.

  14. Dust Obscured Blazars as sources of high-energy neutrinos

    NASA Astrophysics Data System (ADS)

    Maggi, G.; de Vries, K. D.; van Eijndhoven, N.

    2016-08-01

    Active Galactic Nuclei (AGN) are believed to be among the most promising sources of the ultra-high-energy cosmic ray flux. A hadronic component which is accelerated in the high energy environment of an AGN immediately implies the production of high-energy neutrinos. Nevertheless, no clear correlation between AGN and the high-energy cosmic-neutrino flux obtained by IceCube has been found so-far, putting strong limits on the neutrino production at AGN. We discuss a specific type of AGN for which an enhanced neutrino production is expected. This specific sub-set is given by AGN with their high-energy jet directed toward Earth, which is obscured by surrounding dust or gas, defining Dust Obscured Blazars. This type of AGN is predicted to have an enhanced neutrino emission due to the interaction of a possible hadronic component inside the AGN-jet with the surrounding matter. From two different galaxy catalogs, we have selected a sample of nearby sources with the characteristics of Dust Obscured Blazars. This selection is based on observations in the X-ray and radio bands. The data is consequently used to investigate the column density of the surrounding matter, providing an estimate for the neutrino production enhancement due to the nucleon-matter interactions in a beam dump scenario for various dust or gas compositions.

  15. SPECTROPOLARIMETRIC EVIDENCE FOR RADIATIVELY INEFFICIENT ACCRETION IN AN OPTICALLY DULL ACTIVE GALAXY

    SciTech Connect

    Trump, Jonathan R.; Murayama, Takashi; Taniguchi, Yoshi; Impey, Christopher D.; Stocke, John T.; Civano, Francesca; Elvis, Martin; Kelly, Brandon C.; Jahnke, Knud; Koekemoer, Anton M.

    2011-05-01

    We present Subaru/FOCAS spectropolarimetry of two active galaxies in the Cosmic Evolution Survey. These objects were selected to be optically dull, with the bright X-ray emission of an active galactic nucleus (AGN) but missing optical emission lines in our previous spectroscopy. Our new observations show that one target has very weak emission lines consistent with an optically dull AGN, while the other object has strong emission lines typical of a host-diluted Type 2 Seyfert galaxy. In neither source do we observe polarized emission lines, with 3{sigma} upper limits of P{sub BLR} {approx}< 2%. This means that the missing broad emission lines (and weaker narrow emission lines) are not due to simple anisotropic obscuration, e.g., by the canonical AGN torus. The weak-lined optically dull AGN exhibits a blue polarized continuum with P = 0.78% {+-} 0.07% at 4400 A < {lambda}{sub rest} < 7200 A (P = 1.37% {+-} 0.16% at 4400 A < {lambda}{sub rest} < 5050 A). The wavelength dependence of this polarized flux is similar to that of an unobscured AGN continuum and represents the intrinsic AGN emission, either as synchrotron emission or the outer part of an accretion disk reflected by a clumpy dust scatterer. Because this intrinsic AGN emission lacks emission lines, this source is likely to have a radiatively inefficient accretion flow.

  16. Models for infrared emission from IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Rowan-Robinson, M.

    1987-01-01

    Models for the infrared emission from Infrared Astronomy Satellite (IRAS) galaxies by Rowan-Robinson and Crawford, by deJong and Brink, and by Helou, are reviewed. Rowan-Robinson and Crawford model the 12 to 100 micron radiation from IRAS galaxies in terms of 3 components: a normal disk component, due to interstellar cirrus; a starburst component, modeled as hot stars in an optically thick dust cloud; and a Seyfert component, modeled as a power-law continuum immersed in an n(r) variation r sup -1 dust cloud associated with the narrow-line region of the Seyfert nucleus. The correlations between the luminosities in the different components, the blue luminosity, and the X-ray luminosity of the galaxies are consistent with the model. Spectra from 0.1 to 1000 microns are predicted and compared with available observations. The de Jong and Brink, and Helou, model IRAS non-Seyfert galaxies in terms of a cool (cirrus) component and a warm (starburst) component. The de Jong and Brink estimate the face-on internal extinction in the galaxies and find that it is higher in galaxies with more luminous starbursts. In Helou's model the spectrum of the warm component varies strongly with the luminosity in that component. The three models are briefly compared.

  17. IUE observations of Fe 2 galaxies

    NASA Technical Reports Server (NTRS)

    Penston, M. V.; Snijders, M. A. J.; Boksenberg, A.; Haskell, J. D. J.; Fosbury, R. A. E.

    1981-01-01

    Repeated observations of the Seyfert 1 galaxies I Zw 1 and II Zw 136, which have very strong Fe II emission lines in the optical region, were made at low resolution with the IUE Satellite. The ultraviolet spectra are very similar: both are variable and show broad emission features of Fe II (especially the UV multiplets 1, 33, 60, 62, and 63) as well as the emission lines usually strong in Seyferts and quasars. The data strongly support the hypothesis that the optical Fe II emission lines are primarily due to collisional excitation and that resonance fluorescence makes only a minor contribution to the excitation of these lines.

  18. Galaxy interactions and active galactic nuclei in the local universe

    NASA Astrophysics Data System (ADS)

    Ryan, Christopher J.

    2009-06-01

    It has been suggested that galaxy interactions may be the principal mechanism responsible for triggering non-thermal activity in galactic nuclei. This thesis investigates the possible role of interactions in the local Universe by searching for evidence of a causal relationship between major interactions and the initiation of activity in Seyfert galaxies using high-quality, multiwavelength imaging data. The connection between interacting galaxies and Seyferts is explored by comparing the clustering properties of their environments, as quantified by the spatial cross-correlation function amplitude. If a direct evolutionary relationship exists, t