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Sample records for luminous iras source

  1. Evolution of luminous IRAS galaxies: Radio imaging

    NASA Technical Reports Server (NTRS)

    Neff, S. G.; Hutchings, J. B.

    1993-01-01

    In a recent study of IRAS galaxies' optical morphologies, we found that luminous IR sources lie in the IR color-luminosity plane in groups which separate out by optical spectroscopic type and also by degree of tidal disturbance. We found that the most luminous steep-IR-spectrum sources are generally galaxies in the initial stages of a major tidal interaction. Galaxies with active nuclei were generally found to have flatter IR spectra, to cover a range of IR luminosity, and to be in the later stages of a tidal interaction. We proposed a sequence of events by which luminous IR sources evolve: they start as interacting or merging galaxies, some develop active nuclei, and most undergo extensive star-formation in their central regions. Another way to study these objects and their individual evolution is to study their radio morphologies. Radio emission may arise at a detectable level from supernovae in star-forming regions and/or the appearance of an active nucleus can be accompanied by a nuclear radio source (which may develop extended structure). Therefore, the compact radio structure may trace the evolution of the inner regions of IRAS-luminous sources. If the radio sources are triggered by the interactions, we would expect to find the radio morphology related to the optical 'interactivity' of the systems. Here, we explore using the radio emission of IRAS galaxies as a possible tracer of galaxy evolution. We present and discuss observations of the compact radio morphology of 111 luminous IRAS-selected active galaxies covering a wide range of IR and optical properties.

  2. Hubble Space Telescope Observations of the Luminous IRAS Source FSC 10214+4724: A Gravitationally Lensed Infrared Quasar

    NASA Technical Reports Server (NTRS)

    Eisenhardt, Peter R.; Armus, Lee; Hogg, David W.; Soifer, B. T.; Neugebauer, G.; Werner, Michael W.

    1996-01-01

    With a redshift of 2.3, the IRAS source FSC 10214+4724 is apparently one of the most luminous objects known in the universe. We present an image of FSC 10214+4724 at 0.8 pm obtained with the Hubble Space Telescope (HST) WFPC2 Planetary Camera. The source appears as an unresolved (less then 0.06) arc 0.7 long, with significant substructure along its length. The center of curvature of the arc is located near an elliptical galaxy 1.18 to the north. An unresolved component 100 times fainter than the arc is clearly detected on the opposite side of this galaxy. The most straightforward interpretation is that FSC 10214+4724 is gravitationally lensed by the foreground elliptical galaxy, with the faint component a counter-image of the IRAS source. The brightness of the arc in the HST image is then magnified by approx. 100, and the intrinsic source diameter is approx. 0.0l (80 pc) at 0.25 microns rest wavelength. The bolometric luminosity is probably amplified by a smaller factor (approx. 30) as a result of the larger extent expected for the source in the far-infrared. A detailed lensing model is presented that reproduces the observed morphology and relative flux of the arc and counterimage and correctly predicts the position angle of the lensing galaxy. The model also predicts reasonable values for the velocity dispersion, mass, and mass-to-light ratio of the lensing galaxy for a wide range of galaxy redshifts. A redshift for the lensing galaxy of -0.9 is consistent with the measured surface brightness profile from the image, as well as with the galaxy's spectral energy distribution. The background lensed source has an intrinsic luminosity approx. 2 x 10(exp 13) L(solar mass) and remains a highly luminous quasar with an extremely large ratio of infrared to optical/ultraviolet luminosity.

  3. A search for precursors of ultracompact H II regions in a sample of luminous IRAS sources. III. Circumstellar dust properties

    NASA Technical Reports Server (NTRS)

    Molinari, S.; Brand, J.; Cesaroni, R.; Palla, F.

    2000-01-01

    The James Clerk Maxwell Telescope has been used to obtain submillimeter and millimeter continuum photometry of a sample of 30 IRAS sources previously studied in molecular lines and centimeter radio continuum. All the sources have IRAS colours typical of very young stellar objects (YSOs) and are associated with dense gas.

  4. Molecular Cores in Different Evolutionary Stages near Luminous IRAS Sources and UC HII Regions

    NASA Astrophysics Data System (ADS)

    Zhu, Lei; Wu, Yue-Fang

    2007-06-01

    We report the results of 12CO and 13CO J=1 0 observations of eight candidates of Ultra-Compact (UC) HII regions with the Purple Mountain Observatory (PMO) Qinghai 13.7 -m telescope, which resulted in revealing 11 molecular cores. Their masses range from 130 to 1.7×104 Modot, with different spatial scales (1~ 6 pc). Also presented are the relevant HCO+ J=1 0 maps, which enabled us to investigate more detailed structures of these cores. Further comparisons show that four of the cores deviated from the centers of infrared (MIR) emission of Midcourse Space Experiment (MSX), while others correspond either to bright MIR sources or diffuse MIR background. This indicates various evolutionary phases of the cores, including quite early ones for those without MIR sources.

  5. Near Infrared Spectroscopy and the Search for CO Emission in Three Extremely Luminous IRAS Sources; F 09104+4109, F 15307+3252, and PG 1634+706

    NASA Astrophysics Data System (ADS)

    Evans, A. S.

    1997-01-01

    Rest-frame 0.48--1.1 mu m emission line strengths and molecular gas mass (H_2) upper limits for three luminous infrared sources -- the hyperluminous infrared galaxies (HyLIGs: L_ir >= 10(13) L_sun where L_ir ~ L(8-1000microns )) IRAS F09104+4109 (z=0.4417), IRAS F15307+3252 (z=0.926), and the optically-selected QSO PG 1634+706 (z=1.338) -- are presented. Diagnostic emission-line ratios ([O III] lambda 5007/Hβ , [S II] lambda 6724/Hα , [N II] lambda 6583/Hα , and [S III] lambda lambda 9069+9532/Hα ) indicate a Seyfert 2-like spectrum for both infrared galaxies, consistent with previously published work. Upper limits on the molecular gas mass for all three sources are M(H_2) < 1-3 x 10(10) h(-2) \\ M_sun (q_0=0.5, H_0 = 100h km s(-1) Mpc(-1) ), less than the H_2 mass of the most gas-rich infrared galaxies in the local Universe. All three sources have L_IR/L'_CO ~ 1300-2000, the most extreme values for extragalactic sources measured to date. Given the relatively warm far-infrared colors for all three objects, much of their infrared luminosity may emanate from a relatively small quantity of hot dust near the AGN. For IRAS F09104+4109 and IRAS F15307+3252, the implied circumnuclear covering factor of this dust is ~ 90%, while for PG 1634+706 the covering factor is only ~ 15%.

  6. Temperature distribution of dust in luminous IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Carico, David P.

    1989-01-01

    Work is currently in progress to obtain temperature distributions of dust in the most infrared-luminous galaxies. The results presented are of a preliminary nature, representing a zeroth-order approximation. The objects which have been analyzed so far are all galaxies from the Infrared Astronomy Satellite (IRAS) Bright Galaxy Sample with infrared luminosities L sub IR greater than or equal to 10(exp 11) solar luminosity. They are: Arp 220, Mrk 231, Mrk 273, NGC 1614, NGC 3690, NGC 6285/6, and Zw 049.057. The analysis utilized 3.7 micron data from the Palomar 5 m Hale telescope, IRAS data at 12, 25, 60, and 100 microns, and 1 mm continuum data from the CalTech Submillimeter Observatory on Mauna Kea.

  7. Search for Obscured Nucleus in a Luminous IRAS Galaxy NGC 6240

    NASA Technical Reports Server (NTRS)

    Leighly, Karen

    1999-01-01

    IRAS discovered very luminous objects which emit the vast majority of their radiation in the infrared wavelength. The energy source of such a tremendous amount of emission is not understood. Starburst and active galactic nuclei (AGN) are thought to be the origin of their power. X-ray observations are expected to be able to reveal the characteristics of the AGN component. However, some are very X-ray quiet, because the AGN is thought to be obscured by a large column density. In order to determine the primary luminosity of the nucleus, we need an X-ray observation with a wide energy band at least up to several tens of keV. We propose to observe NGC 6240, one of the luminous IRAS galaxies, to investigate the characteristics of its AGN, which must be obscured by large column density.

  8. Extragalactic OH megamasers in strong IRAS sources

    NASA Technical Reports Server (NTRS)

    Bottinelli, L.; Dennefeld, H.; Gouguenheim, L.; Martin, J. M.; Paturel, G.; Lesqueren, A. M.

    1987-01-01

    From the OH and HI survey of the strongest far infrared IRAS sources, 3 new powerful OH megamasers were discovered in Arp 143, IRAS 1510+0724 and in the uncatalogued IRAS source, IRAS 17208-0014. The HI line, the OH 1667 and 1665 MHz main lines and the 21 cm continuum observations were made with Nancy radio telescope. The optical spectra and images were obtained at the European Southern Observatory. The spectra are displayed in figures together with the main IR and OH properties of the 8 megamasers detected up to now, including IC 4553, NGC 3690 and Mrk 231, Mrk 273 and III ZW35.

  9. Extreme optical Fe II emission in luminous IRAS active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Lipari, Sebastian; Terlevich, Roberto; Macchetto, F.

    1993-01-01

    Results of a program of studies and observations of strong optical Fe II emission in luminous and ultraluminous IRAS AGN are presented. New spectroscopic observations and studies of three known ultraluminous IRAS AGN with extreme optical Fe II emission, the discovery that PHL 1092 is a new ultraluminous IRAS AGN, and the detection of two new AGN with strongly variable flux in the optical Fe II emission lines are reported. These results are used to test the correlations between the Fe II emission and properties at other wavelengths such as the L(IR) and the radio emission. IR AGN with extreme Fe II emission are found to belong to a very important group of AGN, whose properties provide insight into the origin of the extreme Fe II emission and into the relation between the starburst and AGN phenomena.

  10. Unidentified IRAS sources: Ultrahigh luminosity galaxies

    NASA Technical Reports Server (NTRS)

    Houck, J. R.; Schneider, D. P.; Danielson, G. E.; Beichman, C. A.; Lonsdale, C. J.; Neugebauer, G.; Soifer, B. T.

    1985-01-01

    Optical imaging and spectroscopy measurements were obtained for six of the high galactic latitude infrared sources reported by Houck, et al. (1984) from the IRAS survey to have no obvious optical counterparts on the POSS prints. All are identified with visually faint galaxies that have total luminosities in the range 5 x 10 to the 11th power stellar luminosity to 5 x 10 to the 12th power stellar luminosity. This luminosity emerges virtually entirely in the infrared. The origin of the luminosity, which is one to two orders of magnitude greater than that of normal galaxies, is not known at this time.

  11. Extremely Luminous Far-infrared Sources (ELFS)

    NASA Technical Reports Server (NTRS)

    Harwit, Martin; Houck, James R.; Soifer, B. Thomas; Palumbo, Giorgio G. C.

    1987-01-01

    The Infrared Astronomical Satellite (IRAS) survey uncovered a class of Extremely Luminous Far Infrared Sources (ELFS), exhibiting luminosities up to and occasionally exceeding 10 to the 12th power L sub 0. Arguments are presented to show that sources with luminosities L equal to or greater than 3 x 10 to the 10th power L sub 0 may represent gas rich galaxies in collision. The more conventional explanation of these sources as sites of extremely active star formation fails to explain the observed low optical luminosities of ELFS as well as their high infrared excess. In contrast, a collisional model heats gas to a temperature of approx. 10 to the 6th power K where cooling takes place in the extreme ultraviolet. The UV is absorbed by dust and converted into far infrared radiation (FIR) without generation of appreciable optical luminosity. Gas recombination as it cools generates a Lyman alpha photon only once for every two extreme ultraviolet approx. 50eV photons emitted by the 10 to the 6th power gas. That accounts for the high infrared excess. Finally, the model also is able to explain the observed luminosity distribution of ELFS as well as many other traits.

  12. Radio properties of extragalactic IRAS sources

    NASA Technical Reports Server (NTRS)

    Condon, J. J.; Broderick, J. J.

    1991-01-01

    The present study identifies extragalactic sources from the IRAS Faint Source Catalog by position coincidence with radio sources stronger than 25 mJy and lying north of +5 deg on the Green Bank 4.85 GHz sky maps. Published VLA maps, new 4.86 GHz VLA maps made with 15-arcsec resolution, and accurate optical positions are used to confirm 122 of these candidate identifications. Normal and starburst spiral galaxies were found to comprise about 97 percent of the FIR flux-limited sample. Radio-loud 'monsters' with q less than 2.25 dominate the radio emission from about 2 percent of the FIR source sample, and radio-quiet monsters are responsible for the FIR emission from less than about 1 percent of the FIR sample. All of the radio-identified sources are optically identified, mostly with relatively bright nearby galaxies. No evidence was found for any new populations of high-redshift FIR sources, nonthermal sources with steep FIR/optical spectra, or dust-shrouded sources visible only at FIR and radio wavelengths.

  13. Ira.

    PubMed

    Petsko, Gregory A

    2003-01-01

    For a quarter of a century in genetics if you said Ira the chances were you meant Ira Herskowitz. When he died, on April 28 this year, it left a hole in the fields of genetics and genomics the size of the Grand Canyon. PMID:12801403

  14. IRAS sources in the direction of rich clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Unewisse, A. M.

    1992-06-01

    Results of a search for possible associations between point sources in the IRAS catalog and rich clusters of galaxies in the recently published Abell, Corwin and Olowin (ACO; (1989)) catalog are presented. It is found that the surface density of IRAS sources rises progressively above the background as the projected distance from the cluster center decreases below about 1 Mpc. The increase is most pronounced for the poorest clusters in the ACO catalog. At low redshift (z less than 0.03) the spatial distribution of ACO-IRAS associations is markedly anisotropic with a 3-sigma enhancement in the direction of the Great Attractor.

  15. IGRINS Spectroscopy of Class I Sources: IRAS 03445+3242 and IRAS 04239+2436

    NASA Astrophysics Data System (ADS)

    Lee, Seokho; Lee, Jeong-Eun; Park, Sunkyung; Lee, Jae-Joon; Kidder, Benjamin; Mace, Gregory N.; Jaffe, Daniel T.

    2016-08-01

    We have detected molecular and atomic line emission from the hot and warm disks of two Class I sources, IRAS 03445+3242 and IRAS 04239+2436, using the high-resolution Immersion GRating INfrared Spectrograph (IGRINS). CO overtone band transitions and near-IR lines of Na i and Ca i, all in emission, trace the hot inner disk, while CO rovibrational absorption spectra of the first overtone transition trace the warm gas within the inner few AU of the disk. The emission-line profiles for both sources show evidence for Keplerian disks. A thin Keplerian disk with power-law temperature and column density profiles with a projected rotational velocity of ˜60–75 km s‑1 and a gas temperature of ˜3500 K at the innermost annulus can reproduce the CO overtone band emission. Na i and Ca i emission lines also arise from this disk, but they show complicated line features possibly affected by photospheric absorption lines. Multi-epoch observations show asymmetric variations of the line profiles on one-year (CO overtone bandhead and atomic lines for IRAS 03445+3242) or on one-day (atomic lines for IRAS 04239+2436) timescales, implying non-axisymmetric features in disks. The narrow CO rovibrational absorption spectra (v = 0 \\to 2) indicate that both warm (>150 K) and cold (˜20–30 K) CO gas are present along the line of sight to the inner disk. This study demonstrates the power of IGRINS as a tool for studies of the sub-AU-scale hot and AU-scale warm protoplanetary disks with its simultaneous coverage of the full H and K bands with high spectral resolution (R = 45,000) allowing many aspects of the sources to be investigated at once.

  16. IGRINS Spectroscopy of Class I Sources: IRAS 03445+3242 and IRAS 04239+2436

    NASA Astrophysics Data System (ADS)

    Lee, Seokho; Lee, Jeong-Eun; Park, Sunkyung; Lee, Jae-Joon; Kidder, Benjamin; Mace, Gregory N.; Jaffe, Daniel T.

    2016-08-01

    We have detected molecular and atomic line emission from the hot and warm disks of two Class I sources, IRAS 03445+3242 and IRAS 04239+2436, using the high-resolution Immersion GRating INfrared Spectrograph (IGRINS). CO overtone band transitions and near-IR lines of Na i and Ca i, all in emission, trace the hot inner disk, while CO rovibrational absorption spectra of the first overtone transition trace the warm gas within the inner few AU of the disk. The emission-line profiles for both sources show evidence for Keplerian disks. A thin Keplerian disk with power-law temperature and column density profiles with a projected rotational velocity of ∼60–75 km s‑1 and a gas temperature of ∼3500 K at the innermost annulus can reproduce the CO overtone band emission. Na i and Ca i emission lines also arise from this disk, but they show complicated line features possibly affected by photospheric absorption lines. Multi-epoch observations show asymmetric variations of the line profiles on one-year (CO overtone bandhead and atomic lines for IRAS 03445+3242) or on one-day (atomic lines for IRAS 04239+2436) timescales, implying non-axisymmetric features in disks. The narrow CO rovibrational absorption spectra (v = 0 \\to 2) indicate that both warm (>150 K) and cold (∼20–30 K) CO gas are present along the line of sight to the inner disk. This study demonstrates the power of IGRINS as a tool for studies of the sub-AU-scale hot and AU-scale warm protoplanetary disks with its simultaneous coverage of the full H and K bands with high spectral resolution (R = 45,000) allowing many aspects of the sources to be investigated at once.

  17. The brightest high-latitude 12-micron IRAS sources

    NASA Technical Reports Server (NTRS)

    Hacking, P.; Beichman, C.; Chester, T.; Neugebauer, G.; Emerson, J.

    1985-01-01

    The Infrared Astronomical Satellite (IRAS) Point Source catalog was searched for sources brighter than 28 Jy (0 mag) at 12 microns with absolute galactic latitude greater than 30 deg excluding the Large Magellanic Cloud. The search resulted in 269 sources, two of which are the galaxies NGC 1068 and M82. The remaining 267 sources are identified with, or have infrared color indices consistent with late-type stars some of which show evidence of circumstellar dust shells. Seven sources are previously uncataloged stars. K and M stars without circumstellar dust shells, M stars with circumstellar dust shells, and carbon stars occupy well-defined regions of infrared color-color diagrams.

  18. Lunar occultations of IRAS point sources, 1986-1990

    NASA Technical Reports Server (NTRS)

    Simon, M.; Chen, W. P.; Cassar, L.

    1986-01-01

    A complete listing is given for objects in the IRAS Point Source Catalog which will be occulted by the moon over the course of 1986-1990. A total of 14,148 ASCII card images is encompassed by the complete listing of objects having geocentric events during this period. The results contained in this complete listing are illustrated in two of the present tables for the brightest objects at 12 and 100 micron wavelengths.

  19. On the possible bipolar nature of 21 micron IRAS sources

    NASA Technical Reports Server (NTRS)

    Hrivnak, Bruce J.; Kwok, S.

    1991-01-01

    The discovery of another IRAS source (22574 + 6609) showing the unidentified 21-micron emission feature is reported. Its overall energy distribution is similar to the well-known edge-on bipolar nebulae AFGL 2688 and AFGL 618. Ground-based optical and infrared observations of this object and two other 21-micron sources show that while all three have very similar infrared properties, they differ greatly in the visual region. All three of these 21-micron sources are intrinsically similar bipolar nebulae, viewed at different orientations.

  20. Infrared and optical imaging of IRAS sources with CO outflow - A snapshot of early star formation

    NASA Technical Reports Server (NTRS)

    Chen, H.; Tokunaga, A. T.; Strom, K. M.; Hodapp, K.-W.

    1993-01-01

    We present multiband imaging of three IRAS sources associated with CO molecular outflows. We find stellar density enhancements around all three IRAS sources. Optical and near-IR photometry indicates that at least 60 percent of the near-IR sources in the vicinity of the IRAS sources are pre-main-sequence stars. Using the photometric data at nbL and M, we are able to identify candidates for the near-IR counterparts of the IRAS sources. We also find that (1) the spectral energy distribution of the deeply embedded sources could be complicated by source confusion and scattered light from the young stellar objects; (2) star formation in the vicinity of the IRAS sources is a continuous process with an age span of 0.5-3 Myr; and (3) stellar density enhancement is probably a phenomenon found at the earliest stage of star formation.

  1. Infrared Images and Millimeter Data from Cold Southern IRAS Sources

    NASA Astrophysics Data System (ADS)

    Osterloh, M.; Henning, Th.; Launhardt, R.

    1997-05-01

    We present near-infrared (H, K'), CO (2-1), CS (2-1), and 1.3 mm continuum data for 31 southern objects [δ(1950) <= 10°] known to have extremely red IRAS colors [Fν(100 μm) > Fν(60 μm) > Fν(25 μm) > 20 × Fν(12 μm)]. The data are meant to help reveal new, very young stellar objects. K'-band near-infrared counterparts to the IRAS point sources are detected in 22 of 25 good K' images. Most K' counterparts are multiples. Eighteen of 21 objects were detected in CS, implying the presence of dense gas. Completing the set of CS (2-1) spectra by including the data of Bronfman, Nyman, & Ray, we still find only three nondetections among all 31 objects; these three were also not detected in K'. Wings indicative of outflows are found in a large fraction (20/30) of CO spectra. Twenty-six of 31 observations in the millimeter continuum were detections and point to the presence of large amounts of circumstellar matter. Most of the objects have 103-105 times solar luminosity; we speculate that most contain at least one massive star capable of producing a compact/ultracompact H II region. Based on observations performed at the European Southern Observatory.

  2. Search for Compact Stellar Groups in the Vicinity of Iras Sources

    NASA Astrophysics Data System (ADS)

    Azatyan, N. M.; Nikoghosyan, E. H.; Khachatryan, K. G.

    2016-09-01

    The results of a search for compact clusters in the vicinity of 19 IRAS sources based on data from the GPS UKIDSS and Spitzer GLIMPSE surveys are presented. Overall, clusters have been identified in 15 regions. Clusters are identified for the first time in 4 regions (IRAS 18151-1208, IRAS 18316-0602, 18517+0437, 19110+1045). In 5 regions (IRAS 05168+3634, 05358+3543, IRAS 18507+0121, IRAS 20188+3928, IRAS 20198+3716) the compact groups we have identified are substructures within more extended clusters. The radii of the identified groups and the surface star density are widely scattered with ranges of 0.3-2.7 pc and 4-1360 stars/pc2, respectively. In 11 of the clusters, the IRAS sources are associated with a pair or even a group of YSOs. The groups identified in the NIR range include representatives of a later II evolutionary class among the stellar objects associated with the IRAS sources.

  3. Constraining Emission Models of Luminous Blazar Sources

    SciTech Connect

    Sikora, Marek; Stawarz, Lukasz; Moderski, Rafal; Nalewajko, Krzysztof; Madejski, Greg; /KIPAC, Menlo Park /SLAC

    2009-10-30

    Many luminous blazars which are associated with quasar-type active galactic nuclei display broad-band spectra characterized by a large luminosity ratio of their high-energy ({gamma}-ray) and low-energy (synchrotron) spectral components. This large ratio, reaching values up to 100, challenges the standard synchrotron self-Compton models by means of substantial departures from the minimum power condition. Luminous blazars have also typically very hard X-ray spectra, and those in turn seem to challenge hadronic scenarios for the high energy blazar emission. As shown in this paper, no such problems are faced by the models which involve Comptonization of radiation provided by a broad-line-region, or dusty molecular torus. The lack or weakness of bulk Compton and Klein-Nishina features indicated by the presently available data favors production of {gamma}-rays via up-scattering of infrared photons from hot dust. This implies that the blazar emission zone is located at parsec-scale distances from the nucleus, and as such is possibly associated with the extended, quasi-stationary reconfinement shocks formed in relativistic outflows. This scenario predicts characteristic timescales for flux changes in luminous blazars to be days/weeks, consistent with the variability patterns observed in such systems at infrared, optical and {gamma}-ray frequencies. We also propose that the parsec-scale blazar activity can be occasionally accompanied by dissipative events taking place at sub-parsec distances and powered by internal shocks and/or reconnection of magnetic fields. These could account for the multiwavelength intra-day flares occasionally observed in powerful blazars sources.

  4. The infrared emission bands. III. Southern IRAS sources.

    PubMed

    Cohen, M; Tielens, A G; Bregman, J; Witteborn, F C; Rank, D M; Allamandola, L J; Wooden, D H; de Muizon, M

    1989-06-01

    We present airborne 5-8 micrometers spectra of southern IRAS sources which reveal strong polycyclic aromatic hydrocarbon (PAH) emission features. The good correlation between the bands, in particular the dominant 6.2 and "7.7" micrometers features, strongly imply a common carrier, reinforcing the PAH hypothesis. However, small but detectable spectral variations exist. Planetaries have a distinctly different ratio of I(6.2)/I(7.7) than other nebulae, accompanied by a redward shift in the actual wavelength of the "7.7" micrometers peak. Further, we have detected a new feature, previously predicted from laboratory spectra of PAH molecules, at 5.2 micrometers in many of these sources. Spectra of two rare [WC 10] planetary nebular nuclei indicate a very prominent plateau of emission, linking the 6.2 and 7.7 micrometers bands. Several of our sources show definite evidence for emission structure between 14 and 23 micrometers in their IRAS Low-Resolution Spectral Atlas spectra: we attribute this structure to PAH bands. too. We have defined the "generic" spectrum of emission bands relating the mean intensities of each band to that of the strongest, near 7.7 micrometers. We have added three more planetary or protoplanetary nebulae to our correlation between 7.7 micrometers band intensity and nebular gas phase C/O ratio, namely NGC 6302, HR 4049, and the highly carbon-rich [WC 10] nucleus, CPD--56 degrees 8032. For the latter we have determined a ratio for C/O of approximately 4.8 from IUE observations. The good correlation between the intensity ratio of the "7.7" micrometers feature relative to the far-infrared dust continuum and nebular C/O also supports a carbonaceous carrier for these emission features. PMID:11542167

  5. First Results from the ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Wolstencroft, R. D.; Wehrle, A. E.; Levine, D. A.

    1997-01-01

    We present the first result from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12um ISOCAM AND 90um ISOPHOT observation.

  6. A STRING OF RADIO EMISSION ASSOCIATED WITH IRAS 16562-3959: A COLLIMATED JET EMANATING FROM A LUMINOUS MASSIVE YOUNG STELLAR OBJECT

    SciTech Connect

    Guzman, Andres E.; Garay, Guido; Brooks, Kate J.

    2010-12-10

    We report the discovery, made using the Australia Telescope Compact Array, of a remarkable string of radio emission toward IRAS 16562-3959, a luminous infrared source with a bolometric luminosity of 7.0 x 10{sup 4} L{sub sun}. The radio emission arises from a compact, bright central component, two inner lobes which are separated by about 7'' and symmetrically offset from the central source, and two outer lobes which are separated by about 45''. The emission from the central object has a spectral index between 1.4 and 8.6 GHz of 0.85 {+-} 0.15, consistent with free-free emission from a thermal jet. The radio emission from the lobes has spectral indices in the range characteristic of thermal emission. We suggest that the emission from the lobes arises in shocks resulting from the interaction of a collimated wind with the surrounding medium. The radio string is located within a massive dense molecular core, and is associated with extended green emission (Spitzer three-color), Herbig-Haro-type emission (2MASS K{sub s} band), and OH maser sites-all phenomena readily observed toward sites of massive star formation. We conclude that the massive core hosts a high-mass star in an early stage of evolution in which it is undergoing the ejection of a powerful collimated stellar wind, showing that jets found in the formation of low-mass stars are also produced in high-mass stars.

  7. Discovery of luminous star formation in PMN 1452-5910/IRAS 14482-5857: The Pterodactyl nebula

    SciTech Connect

    Jones, D. I.

    2015-02-01

    We present sensitive 1–3 GHz ATCA radio continuum observations of the hitherto unresolved star-forming region known as either IRAS 14482-5857 or PMN 1452-5910. At radio continuum frequencies, this source is characterized by a “filled bubble” structure reminiscent of a classical Hii region, dominated by three point sources and surrounded by low surface brightness emission out to the ∼3{sup ′}×4{sup ′} source extent observed at other frequencies in the literature. The infrared emission corresponds well to the radio emission, with polycyclic aromatic hydrocarbon emission surrounding regions of hot dust toward the radio bubbles. A bright 4.5 μm point source is seen toward the center of the radio source, suggesting a young stellar object. There is also a linear, outflowlike structure radiating brightly at 8 and 24 μm toward the brightest peak of the radio continuum. In order to estimate the distance to this source, we have used Mopra Southern Galactic Plane CO Survey {sup 12}CO (1–0) and {sup 13}CO(1–0) molecular line emission data. Integrated intensity, velocity at peak intensity, and line fitting of the spectra all point toward the peak centered at V {sub LSR} =−1.1 km s{sup −1} being connected to this cloud. This infers a distance to this cloud of ∼12.7 kpc. Assuming this distance, we estimate a column density and mass toward IRAS 14482-5857 of ∼1.5×10{sup 21} cm{sup −2} and 2 × 10{sup 4} M {sub ⊙} , implying that this source is a site of massive star formation. Reinforcing this conclusion, our broadband spectral fitting infers dust temperatures of 19 and 110 K, emission measures for the sub-parsec radio point source of EM∼10{sup 6−7} pc cm{sup −6}, electron densities of n{sub e}∼10{sup 3} cm{sup −3}, and photon ionization rates of N{sub Ly}∼10{sup 46−48} s{sup −1}. The evidence strongly suggests that IRAS 14482-5857 is a distant—hence intense—site of massive star formation.

  8. Compact radio sources in luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Parra, Rodrigo

    2007-08-01

    Radio interferometry is an observational technique of high sensitivity and incomparably high spatial resolution. Moreover, because radio waves can freely propagate through interstellar dust and gas, it allows the study of regions of the universe completely obscured at other wavelengths. This thesis reports the observational and theoretical results of my research during the past four years which are mostly based on interferometric radio data. The COLA sample is an infrared selected sample of active star forming galaxies. We conducted 6 cm VLA and VLBI snapshot observations of the northern half of this sample. The radio emission seen at VLA scales is consistent with being powered by star formation activity because it follows the far infrared to radio correlation. We detect 22% of the sample sources in our VLBI snapshots. Based on luminosity arguments, we argue that these sub-parsec VLBI sources are powered by AGN activity. Furthermore, we find that VLBI detections are preferentially found in sources whose VLA scale structures have the highest peak brightnesses suggesting a strong correlation between compact starburst and AGN activity. This observational result is consistent with the theoretical picture of an Eddington-limited nuclear starburst acting as the last valve in the pipeline transporting the gas from kiloparsec scales onto the accretion disc of a buried AGN. Arp 220 is the archetypical ultra luminous infrared galaxy. For many years this source has been known to harbour a compact (~100 pc) cluster of unresolved 18 cm bright sources believed to be bright core collapse supernovae. Using multiwavelength VLBI observations, we obtained for the first time radio spectra for 18 of these sources. We find that over a half of them have spectra consistent with young supernovae. The rest can be better explained as older supernova remnants interacting with the high density starburst ISM. This finding allowed us to constrain the number of possible scenarios for the Arp 220

  9. Ultra Luminous X-ray Sources

    NASA Astrophysics Data System (ADS)

    Webb, N. A.; Godet, O.

    2015-12-01

    Ultra Luminous X-ray sources (ULXs) are X-ray bright objects that are not coincident with the central nucleus of the host galaxy and which have luminosities that exceed the Eddington limit for a stellar mass black hole, typically L > 3 × 10^{39} erg s^{-1} for a black hole of 20 M_⊙. The nature of these objects is still unclear. However, it is possible that these sources do not form a single class of objects. Many ULXs may house stellar mass black holes accreting at super-Eddington rates, even if the physical mechanism for such high accretion rates is still not understood. Some ULXs may contain intermediate mass black holes (˜1 × 10^{2} - ˜1 × 10^{5} M_⊙). These elusive black holes are thought to be the building blocks of the more massive supermassive black holes, observed at the centre of many galaxies. Other ULXs may not be accreting black holes at all. Recent evidence for the different types of ULXs is presented in this paper.

  10. Optical spectroscopy of IRAS sources with infrared emission bands. 1: IRAS 21282+5050 and the diffuse interstellar bands

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Jones, B. F.

    1987-01-01

    Spectroscopy of the starlike optical counterpart to IRAS 21282+5050, a source with the hydrocarbon infrared emission band spectrum, shows an 07(f)-(WC11) planetary nebula nucleus suffering an extinction of 5.7 mag. Emission line widths in the WC spectrum are only approx. 100 km/s, indicating a very slow stellar wind. Optical diffuse interstellar bands (DIBs) are prominent. Five DIBs are strongly enhanced, namely lamda lamda 5797, 6196, 6203, 6283, and 6613. The presence of circumstellar hydrocarbon molecules may explain both the infrared emission bands and the enhanced DIBs.

  11. 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

  12. H2O and CO emission towards IRAS point sources in regions of star formation.

    NASA Astrophysics Data System (ADS)

    Fiegle, K.; Wouterloot, J. G. A.; Brand, J.

    H2O masers are good indicators for the presence of star formation in molecular clouds. Wouterloot and Walmsley (1986) showed that all H2O maser sources in regions of star formation are associated with IRAS point sources with specific colours, so that the IRAS Point Source Catalog can be used to select maser candidates. The authors have searched for 22 GHz H2O maser emission using the 100-m radiotelescope in Effelsberg and the 32-m radiotelescope in Medicina, Italy. The total sample of sources consists of 1390 objects, selected according to their IRAS colour indices. Spectra and line parameters are given in Wouterloot et al. (1993). The H2O data are compared with results of observations of 12CO (1-0) (and of 12CO (2-1) and 12CO(3-2) in some cases) towards a large fraction of these sources, made with the 30-m IRAM, 15-m SEST, or 3-m KOSMA telescopes.

  13. WATER MASER SURVEY ON AKARI AND IRAS SOURCES: A SEARCH FOR ''LOW-VELOCITY'' WATER FOUNTAINS

    SciTech Connect

    Yung, Bosco H. K.; Nakashima, Jun-ichi; Kwok, Sun; Imai, Hiroshi; Deguchi, Shuji; Henkel, Christian

    2013-05-20

    We present the results of a 22 GHz H{sub 2}O maser survey toward a new sample of asymptotic giant branch (AGB) and post-AGB star candidates. Most of the objects are selected for the first time based on the AKARI data, which have high flux sensitivity in the mid-infrared ranges. We aim at finding H{sub 2}O maser sources in the transient phase between the AGB and post-AGB stages of evolution, where the envelopes start to develop large deviations from spherical symmetry. The observations were carried out with the Effelsberg 100 m radio telescope. Among 204 observed objects, 63 detections (36 new) were obtained. We found four objects that may be ''water fountain'' sources (IRAS 15193+3132, IRAS 18056-1514, OH 16.3-3.0, and IRAS 18455+0448). They possess an H{sub 2}O maser velocity coverage much smaller than those in other known water fountains. However, the coverage is still larger than that of the 1612 MHz OH maser. It implies that there is an outflow with a higher velocity than the envelope expansion velocity (typically {<=}25 km s{sup -1}), meeting the criterion of the water fountain class. We suggest that these candidates are possibly oxygen-rich late AGB or early post-AGB stars in a stage of evolution immediately after the spherically symmetric AGB mass loss has ceased.

  14. ALMA DETECTION OF THE VIBRATIONALLY EXCITED HCN J = 4-3 EMISSION LINE IN THE AGN-HOSTING LUMINOUS INFRARED GALAXY IRAS 20551–4250

    SciTech Connect

    Imanishi, Masatoshi; Nakanishi, Kouichiro

    2013-10-01

    We present results from our ALMA Cycle 0 observations, at the frequencies around the HCN, HCO{sup +}, and HNC J = 4-3 transition lines, of the luminous infrared galaxy IRAS 20551–4250 at z = 0.043, which is known to host an energetically important obscured active galactic nucleus (AGN). In addition to the targeted HCN, HCO{sup +}, and HNC J = 4-3 emission lines, two additional strong emission lines are seen, which we attribute to H{sub 2}S and CH{sub 3}CN(+CCH). The HCN-to-HCO{sup +} J = 4-3 flux ratio (∼0.7) is higher than in the other starburst-dominated galaxy (∼0.2) observed in our ALMA Cycle 0 program. We tentatively (∼5σ) detected the vibrationally excited (v {sub 2} = 1) HCN J = 4-3 (l = 1f) emission line, which is important for testing an infrared radiative pumping scenario for HCN. This is the second detection of this molecular transition in external galaxies. The most likely reason for this detection is not only the high flux of this emission line, but also the small molecular line widths observed in this galaxy, suggesting that vibrational excitation of HCN may be relatively common in AGN-hosting galaxies.

  15. Optical spectroscopy of IRAS sources with infrared emission bands. II. IRAS 04324+5106, 06114+1745, 20319+3958, and 22539+5758

    SciTech Connect

    Cohen, M.; Jones, B.F.; Walker, H.J.; Lick Observatory, Santa Cruz, CA; Search for Extraterrestrial Intelligence Institute, Los Altos, CA )

    1989-06-01

    The paper presents long-slit optical spectra and microwave CO spectra of four nebulous counterparts to IRAS sources showing PAH emission features: 04324+5106, 06114+1745, 20319+3958, and 22539+5758. IRAS 22539+5758 is associated with a bipolar nebula. All are allied with B-type stars that suffer appreciable circumstellar extinction, and whose environs show atomic emission lines; three represent mixed reflection/emission nebulosities. Three show spectroscopic evidence for outflows at about 100 km/s. One, 06114+1745, exhibits indications of enhanced diffuse interstellar bands. It is concluded that extinction alone is insufficient to yield enhanced DIBs and that peculiar circumstellar abundances and/or physical conditions must play a role. 20 refs.

  16. Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-103Pd brachytherapy source.

    PubMed

    Sadeghi, Mahdi; Raisali, Gholamreza; Hosseini, S Hamed; Shavar, Arzhang

    2008-04-01

    This article presents a brachytherapy source having 103Pd adsorbed onto a cylindrical silver rod that has been developed by the Agricultural, Medical, and Industrial Research School for permanent implant applications. Dosimetric characteristics (radial dose function, anisotropy function, and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task group 43 (TG-43U1) recommendations. Monte Carlo simulations were used to calculate the dose rate constant. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located the dosimeters and the source in a reproducible fixed geometry, providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-particle (MCNP) code, version 4C simulation techniques have been used to evaluate the dose-rate distributions around this model 103Pd source in water and Perspex phantoms. The Monte Carlo calculated dose rate constant of the IRA-103Pd source in water was found to be 0.678 cGy h(-1) U(-1) with an approximate uncertainty of +/-0.1%. The anisotropy function, F(r, theta), and the radial dose function, g(r), of the IRA- 103Pd source were also measured in a Perspex phantom and calculated in both Perspex and liquid water phantoms. PMID:18491522

  17. DISCOVERY OF THE SECOND WARM CARBON-CHAIN-CHEMISTRY SOURCE, IRAS15398 - 3359 IN LUPUS

    SciTech Connect

    Sakai, Nami; Yamamoto, Satoshi; Sakai, Takeshi; Hirota, Tomoya; Burton, Michael

    2009-05-20

    We have conducted a search for carbon-chain molecules toward 16 protostars with the Mopra 22 m and Nobeyama 45 m telescopes, and have detected high excitation lines from several species, such as C{sub 4}H (N = 9-8), C{sub 4}H{sub 2}(J = 10{sub 0,10}-9{sub 0,9}), CH{sub 3}CCH(J = 5-4, K = 2), and HC{sub 5}N(J = 32-31), toward the low-mass protostar, IRAS15398 - 3359 in Lupus. The C{sub 4}H line is as bright as 2.4 K measured with the Nobeyama 45 m telescope. The kinetic temperature is derived to be 12.6 {+-} 1.5 K from the K = 1 and K = 2 lines of CH{sub 3}CCH. These results indicate that the carbon-chain molecules exist in a region of warm and dense gas near the protostar. The observed features are similar to those found toward IRAS04368+2557 in L1527, which shows warm carbon-chain chemistry (WCCC). In WCCC, carbon-chain molecules are produced efficiently by the evaporation of CH{sub 4} from the grain mantles in a lukewarm region near the protostar. Our data clearly indicate that WCCC is no longer specific to L1527, but occurs in IRAS15398 - 3359. In addition, we draw attention to a remarkable contrast between WCCC and hot corino chemistry in low-mass star-forming regions. Carbon-chain molecules are deficient in hot corino sources like NGC1333 IRAS4B, whereas complex organic molecules seem to be less abundant in the WCCC sources. A possible origin for such source-to-source chemical variations is suggested to arise from the timescale of the starless-core phase in each source. If this is the case, the chemical composition provides an important clue to explore the variation of star formation processes between sources and/or molecular clouds.

  18. The Stellar Population Associated with the IRAS Source 16132-5039

    NASA Astrophysics Data System (ADS)

    Roman-Lopes, A.; Abraham, Z.

    2004-05-01

    We report the discovery of a young massive stellar cluster and infrared nebula in the direction of the CS molecular cloud associated with the IRAS point source 16132-5039. Analysis of mid-infrared images from the more accurate Midcourse Space Experiment catalog reveals that there are two independent components associated with the IRAS source. The integral of the spectral energy distribution for these components between 8.28 and 100 μm gives lower limits for the bolometric luminosity of the embedded objects of 8.7×104 and 9×103 Lsolar, which correspond to zero-age main-sequence O8 and B0.5 stars, respectively. The number of Lyman continuum photons expected from the stars that lie along the reddening line for early-type stars is about 1.7×1049 s-1, enough to produce the detected flux densities at 5 GHz. The near-infrared spectrum of the nebula increases with frequency, implying that free-free emission cannot be the main source of the extended luminosity, from which we conclude that the observed emission must be mainly dust-scattered light. A comparison of the cluster described in this paper with the young stellar cluster associated with the IRAS source 16177-5018, which is located at the same distance and in the same direction, shows that the mean visual absorption of the newly discovered cluster is about 10 mag smaller and that it contains less massive stars, suggesting that it was formed from a less massive molecular cloud. Based on observations made at the Laboratório Nacional de Astrofisica, Ministério da Ciência e Tecnologia, Brazil.

  19. H2O maser survey of IRAS sources at high galactic latitude

    NASA Astrophysics Data System (ADS)

    Caselli, P.; Codella, C.; Palumbo, G. G. C.; Pareschi, G.

    A high galactic latitude sample of 175 IRAS sources located within the core of molecular clouds has been searched for H2O maser emission with the Medicina 32 m dish operated at 22 GHz. Seventeen percent of the sample previously searched by other authors contained only four detections. The search did not produce any new water maser emitter, while the previously known maser were seen again. The low value of 2 percent overall detection rate can be explained in terms of Galactic distribution of massive cores.

  20. The Joint IRAS PSC/FSC catalogue as a tool for efficient studies for extragalactic IR sources

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Abrahamyan, H. V.; Harutyunyan, G. S.

    2014-12-01

    To increase the efficiency of using IRAS PSC and FSC, which contain a lot of common sources, one needs a joint catalogue of all IRAS point sources with improved data based on both catalogues. We have combined these two catalogs and obtained 345,163 sources, including 73,770 common associations with improved data. In addition, we have made cross-correlations with AKARI/IRC, AKARI/FIS and WISE catalogues. As a result we created a catalogue with high positional accuracy and with 17 photometric measurements from 1.25m to 160mwavelength range (based on 2MASS, WISE, IRAS, and AKARI). At least half of all sources are extragalactic ones, which include bright galaxies, AGN and especially many Starburst galaxies that are important for star-formation phenomena and in many cases for study of the interrelationship between starburst, interactions and nuclear activity.

  1. A study of the stellar population in the Lynds 1641 dark cloud. I - The IRAS catalog sources

    NASA Technical Reports Server (NTRS)

    Strom, Karen M.; Newton, Geoffrey; Strom, Stephen E.; Seaman, Robert L.; Carrasco, Luis

    1989-01-01

    The character of the sources identified in the IRAS Point Source Catalog and located within the boundaries of the nearest giant molecular cloud, Lynds 1641 is discussed. New optical and near-infrared photometry are combined to provide spectral energy distributions (SEDs) for these objects divided into three classes: class I objects with flat or rising spectra, class II objects with spectra intermediate in slope between a flat and blackbody spectrum, and class III objects with spectra similar to those of blackbodies. It is found that L1641 contains a much larger percentage of class I sources than does the nearby Taurus-Auriga star-forming complex. Spectral energy distributions for the IRAS-selected sample are examined and compared with SEDs for young stellar objects (YSOs) located in Taurus-Auriga. The IRAS-selected sources having optical counterparts in the H-R diagram are identified and discussed along with the distribution of masses and ages for these YSOs.

  2. Discovery of a Young Massive Stellar Cluster Associated with IRAS Source 16177-5018

    NASA Astrophysics Data System (ADS)

    Roman-Lopes, A.; Abraham, Z.; Lépine, J. R. D.

    2003-10-01

    We report the discovery of a young massive stellar cluster embedded in an extended H II region, invisible at optical wavelengths where the extinction is AV~28 mag, associated with the IRAS source 16177-5018. J-, H-, and narrowband K-imaging photometry combined with the Ks Two Micron All Sky Survey data show the presence of sources with excess infrared emission at 2.2 μm, concentrated in an area of about 1 pc2 around a massive young stellar object identified as the IRAS source. This object has a near mid-infrared spectral index between 2.2 and 25 μm α(IR)=dlog(λFλ)/dlogλ=4.78, characteristic of compact H II regions, with bolometric luminosity inferred from the integrated near-to-far-infrared flux density of 2.8×105Lsolar, which corresponds to a zero-age main-sequence star of about 42 Msolar. From the color-magnitude diagram we were able to classify the majority of the cluster members as reddened massive stars earlier than spectral type B5. Based on observations made at Laboratório Nacional de Astrofisica, Ministério da Ciência e Tecnologia, Brazil.

  3. Near-infrared study of southern massive star formation regions. The case of IRAS 16571-4029 source

    NASA Astrophysics Data System (ADS)

    Roman-Lopes, A.

    2007-09-01

    Context: We present the results of a near-infrared survey of the young stellar cluster associated with the IRAS 16571-4029 source. Aims: The main purpose of this survey is to study the cluster members and find the ionizing sources of the associated HII region. Methods: The stellar population was studied by using color-color and color-magnitude diagrams, as well as by analysing the spectral energy distributions in the near- and mid-infrared wavelengths. The extended emission was studied by the construction of contour diagrams, which were compared with near- and mid-infrared images. We computed the corresponding number of Lyman continuum photons (using the integrated Brγ flux density) and compared it with that obtained from the 5 GHz flux density to derive a mean visual extinction. Results: NIR observations in the direction of RCW116B reveal the presence of a young cluster of massive stars coincident with the IRAS 16571-4029 source. These observations, together with published radio data, MSX, and Spitzer images were used to determine some of the physical parameters of the region. We found 102 cluster member candidates in an area of about 3 × 3 square arcmin, the majority of them showing excess emission in the NIR. We found that IRAS 16571-4029 is formed by multiple infrared sources, all but one are associated with small groups of stars. This suggests that the fragmentation of massive molecular clouds generates the massive sub-clusters. We derived a mean visual extinction of A_V=12.8± 4.73.2. This result is independent of the assumed distance and agrees with the mean visual extinction A_V=14.4, as obtained by previous spectroscopic observations of two NIR sources in the direction of the IRAS 16571-4029 source. We also compare the results obtained in this study with those obtained in previous papers in this series finding a very good correlation between the number of cluster members Ns and the cluster radius r_c. The cluster radius varies from 0.2-0.3 pc (IRAS 15411

  4. A multifrequency radio continuum and IRAS faint source survey of markarian galaxies

    NASA Technical Reports Server (NTRS)

    Bicay, M. D.; Kojoian, G.; Seal, J.; Dickinson, D. F.; Malkan, M. A.

    1995-01-01

    Results are presented from a multifrequency radio continumm survey of Markarian galaxies (MRKs) and are supplemented by IRAS infrared data from the Faint Source Survey. Radio data are presented for 899 MRKs observed at nu = 4.755 GHz with the National Radio Astronomy Observatory (NRAO)-Green Bank 300 foot (91 m) telescope, including nearly 88% of those objects in Markarian lists VI-XIV. In addition, 1.415 GHz measurements of 258 MRKs, over 30% of the MRKs accessible from the National Aeronomy and Ionosphere Center (NAIC)-Arecibo, are reported. Radio continuum observations of smaller numbers of MRKs were made at 10.63 GHz and at 23.1 GHz and are also presented. Infrared data from the IRAS Faint Source Survey (Ver. 2) are presented for 944 MRKs, with reasonably secure identifications extracted from the NASA/IPAC Extragalactic Database. MRKs exhibit the same canonical infrared characteristics as those reported for various other galaxy samples, that is well-known enhancement of the 25 micrometer/60 micrometer color ratio among Seyfert MRKs, and a clear tendency for MRKs with warmer 60 micrometer/100 micrometer colors to also possess cooler 12 micrometer/25 micrometer colors. In addition, non-Seyfert are found to obey the well-documented infrared/radio luminosity correlation, with the tightest correlation seen for starburst MRKs.

  5. IRAS 15099-5856: REMARKABLE MID-INFRARED SOURCE WITH PROMINENT CRYSTALLINE SILICATE EMISSION EMBEDDED IN THE SUPERNOVA REMNANT MSH15-52

    SciTech Connect

    Koo, Bon-Chul; Kim, Hyun-Jeong; Im, Myungshin; McKee, Christopher F.; Suh, Kyung-Won; Moon, Dae-Sik; Lee, Ho-Gyu; Onaka, Takashi; Burton, Michael G.; Hiramatsu, Masaaki; Bessell, Michael S.; Gaensler, B. M.; Lee, Jae-Joon; Jeong, Woong-Seob; Tatematsu, Ken'ichi; Kawabe, Ryohei; Ezawa, Hajime; Kohno, Kotaro; Wilson, Grant; Yun, Min S.

    2011-05-01

    We report new mid-infrared (MIR) observations of the remarkable object IRAS 15099-5856 using the space telescopes AKARI and Spitzer, which demonstrate the presence of prominent crystalline silicate emission in this bright source. IRAS 15099-5856 has a complex morphology with a bright central compact source (IRS1) surrounded by knots, spurs, and several extended ({approx}4') arc-like filaments. The source is seen only at {>=}10 {mu}m. The Spitzer mid-infrared spectrum of IRS1 shows prominent emission features from Mg-rich crystalline silicates, strong [Ne II] 12.81 {mu}m, and several other faint ionic lines. We model the MIR spectrum as thermal emission from dust and compare with the Herbig Be star HD 100546 and the luminous blue variable R71, which show very similar MIR spectra. Molecular line observations reveal two molecular clouds around the source, but no associated dense molecular cores. We suggest that IRS1 is heated by UV radiation from the adjacent O star Muzzio 10 and that its crystalline silicates most likely originated in a mass outflow from the progenitor of the supernova remnant (SNR) MSH 15-52. IRS1, which is embedded in the SNR, could have been shielded from the SN blast wave if the progenitor was in a close binary system with Muzzio 10. If MSH 15-52 is a remnant of Type Ib/c supernova (SN Ib/c), as has been previously proposed, this would confirm the binary model for SN Ib/c. IRS1 and the associated structures may be the relics of massive star death, as shaped by the supernova explosion, the pulsar wind, and the intense ionizing radiation of the embedded O star.

  6. A search for T Tauri stars based on the IRAS point source catalog.

    NASA Astrophysics Data System (ADS)

    Gregorio-Hetem, J.; Lepine, J. R. D.; Quast, G. R.; Torres, C. A. O.; de La Reza, R.

    1992-02-01

    The results of the first part of a survey for new T Tauri stars, with spectroscopic and photometric observations of about 100 stars, are presented. A list of candidates has been selected by means of the IRAS Point Source Catalog, based on appropriate far-infrared colors. Coude spectra of the selected objects in the 655-673 nm wavelength range, which includes H-alpha and the resonance Li I line, have been obtained. Thirty-three new T Tauri stars, and a number of other interesting objects, like early type premain-sequence stars and Li-rich K giants, have been detected. Several new isolated T Tauri were found, including Hen 1, which may be the T Tauri star with the highest galactic latitude known, if its nature is confirmed.

  7. Formation and evolution of luminous supersoft X-ray sources

    NASA Technical Reports Server (NTRS)

    Rappaport, S.; Di Stefano, R.; Smith, J. D.

    1994-01-01

    Luminous supersoft X-ray sources, with characteristic luminosities of approximately 10(exp 38) ergs/s and temperatures, kT, of approximately 35 eV, have been established as a new and distinct class of X-ray source through recent Roentgen Satellite (ROSAT) observations. Several possible physical models have been proposed for these sources. One promising scenario (van den Heuvel et al. 1992) involves mass transfer, which is unstable on a thermal timescale, from a main-sequence or subgiant donor star onto the surface of a white dwarf. For a narrow range of accretion rates, steady nuclear burning of the accreted matter can take place. This process can provide the high luminosities and the correct range of temperatures observed in the supersoft sources. However, given the limited range of mass transfer rates that are consistent with this phenomenon, it is far from obvious that a sufficient population of such systems exists in galaxies such as our own, M31, and the Magellanic Clouds, in order to account for the large number of supersoft sources which can be inferred from present observations. This work addresses the population question in detail, through a Monte Carlo simulation of the formation and evolution of such systems, which starts with zero-age primordial binaries. In order to evolve into close binary systems which contain a white dwarf component and a companion transferring mass at a rate within the requisite narrow range, a binary system must undergo a specific progression of evolutionary steps. We find that a sufficient subset of our initial binaries evolve to become systems with the requisite properties, so that they can account for the population of supersoft sources that is inferred from observations. In particular, we find that there should be more than 1000 systems in the Galaxy today with properties that very closely match those of the observed supersoft sources. From our models, we find expected luminosities, white dwarf effective temperatures, and

  8. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 5: The point source catalog declination range -30 deg greater than delta greater than -50 deg

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched January 26, 1983. During its 300-day mission, IRAS surveyed over 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. This is Volume 5, The Point Source Catalog Declination Range -30 deg greater than delta greater than -50 deg.

  9. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 3: The point source catalog declination range 30 deg greater than delta greater than 0 deg

    SciTech Connect

    Not Available

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched January 26, 1983. During its 300-day mission, IRAS surveyed over 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. This is Volume 3, The Point Source Catalog Declination Range 30 deg greater than delta greater than 0 deg.

  10. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 2: The point source catalog declination range 90 deg greater than delta greater than 30 deg

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched January 26, 1983. During its 300-day mission, IRAS surveyed 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. This is Volume 2, The Point Source Catalog Declination Range 90 deg greater than delta greater than 30 deg.

  11. Spectral variability of the IR source IRAS 01005+7910 optical component

    NASA Astrophysics Data System (ADS)

    Klochkova, V. G.; Chentsov, E. L.; Panchuk, V. E.; Sendzikas, E. G.; Yushkin, M. V.

    2014-10-01

    High-resolution optical spectra of the IR source IRAS01005+7910 are used to determine the spectral type of its central star, B1.5±0.3, identify the spectral features, and analyze their profile and radial-velocity variations. The systemic velocity V sys = -50.5 km s-1 is determined from the positions of the symmetric and stable profiles of the forbidden [NI], [N II], [OI], [S II], and [Fe II] emission lines. The presence of the [NII] and [SII] forbidden emissions indicates the onset of the ionization of the circumstellar envelope and the fact that the star is very close to undergoing the planetary nebula stage. The broad range of radial velocity V r estimates based on the line cores, which amounts to about 34 km s-1, is partly due to the deformations of the profiles caused by variable emissions. The variations of the V r in the line wings are smaller, about 23 km s-1, and may be due to pulsations and/or hidden binarity of the star. The deformations of the profiles of absorption-emission lines may result from variations of their absorption components caused by the variations of the geometry and kinematics in the wind base. The H α lines exhibit PCyg III type wind profiles. Deviations of the wind from spherical symmetry are shown to be small. The relatively low wind velocity (27-74 km s-1 from different observations) and the strong intensity of the red emission (it exceeds the continuum level by up to a factor of seven) are typical for hypergiants rather than the classical supergiants. IRAS01005 is an example of spectral mimicry of a low-mass post-AGB star masquerading as a massive hypergiant.

  12. Investigating the Extraordinary X-Ray Variability of the Infrared Quasar IRAS 13349+2439

    NASA Technical Reports Server (NTRS)

    Leighly, Karen M.

    1999-01-01

    We observed the luminous quasar IRAS 13349+2439 using RXTE (X Ray Timing Explorer) in order to search for rapid variability. Unfortunately, the source was in a low state during the observation (PCA count rate approximately 1 - 2 counts/s). It was therefore somewhat weak for RXTE and detailed analysis proved to be difficult.

  13. The ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Smith, Harding E.

    1999-01-01

    As part of the ISO-IRAS Faint Galaxy Survey ISO Satellite observations of over 600 IRAS sources have been obtained with the ISOCAM instrument. Because our survey strategy involved relatively short integrations, great care was required in developing analysis software including cosmic-ray and transient removal and calibration. These observations have now been through final pipeline processing at IPAC and ground-based follow-up is ongoing. The observations are for sources from two samples: a " Filler' sample selected to be at z greater than 0.1 and a fainter sample which selected for the highest redshift galaxies in the IRAS survey, with redshifts 0.2 less than z less than 1.0. I now have obtained ground-based follow-up spectrophotometry at Lick and Palomar observatories for 100 LFIRGs with 0.1 less than z less than 0.7. Our observations have confirmed that these systems are comparable to nearby LFIRGs such as Arp 220, with L (sub -)(fir) greater than 10(exp 11) L(sub -) sun and typically HII/Liner optical excitation. About 10% of the galaxies show true AGN (Sy2) excitation. Based on our work on a nearby complete sample of LFIRGS, we believe that the majority of these systems are luminous Starbursts, thus this project is tracing the luminous end of the galaxy star-forming luminosity function - the (infrared) star-formation history of the Universe to z approx. 1, a topic of some considerable recent interest. A by-product of these ISOCAM observations is approximately 1 square degree of deep 2 microns pointings outside the IRAS error boxes, allowing us an independent estimate of the mid-infrared log N - log S relation. Ground-based observations of this sample are continuing.

  14. Shocked molecular gas around the extremely young source IRAS 03282+3035

    NASA Technical Reports Server (NTRS)

    Bachiller, R.; Terebey, S.; Jarrett, T.; Martin-Pintado, J.; Beichman, C. A.; Van Buren, D.

    1994-01-01

    We present observations of the shock tracers H2 and SiO around the young stellar object IRAS 03282+3035. This unusual low-luminosity (L approximately = 2 solar luminosity) source drives a strong highly collimated CO outflow, and it is one of the youngest stellar objects known so far. The near-infrared H2 emission, tracing 2000 K gas, comes from extremely high velocity CO bullets along the axis of the blueshifted lobe of the outflow. The millimeter SiO emission, tracing roughly 100 K gas, arises from lower velocity material at the end of the outflow lobe. The lack of high-temperature and high-velocity gas at the end of the outflow lobe indicates there is no not bow shock at the outflow termination. In the context of current jet models this appears to rule out a bow shock driven by a steady state jet. Possible explanations for the structure include a time-dependent jet or a jet dominated by turbulent entrainment.

  15. VizieR Online Data Catalog: IRAS Point Source Identifications (MacConnell, 1993; rev. 2009)

    NASA Astrophysics Data System (ADS)

    MacConnell, D. J.

    2010-08-01

    Most of the sources are south of the celestial equator and have been classified in increasing galactic longitude over the period Sept. 1985 to May 1992. They have been classified on Kodak I-N objective-prism plates taken primarily with the Curtis Schmidt telescope at Cerro Tololo, but some northern plates taken with the Burrell Schmidt at Kitt Peak were also used for classification. The spectra cover the range 680-880nm at a dispersion of 340nm/mm at the A-band, and the plate scale is 96.6"/mm. They are ideal for classifying M stars of type M3 and cooler (increasing strength of TiO and VO bands) and carbon stars (CN bands), but stars warmer than M2 and most S stars cannot be classified or identified as such. The M stars M3 and cooler can be separated into about five groups. The limiting mag of the deepest plates is I about 13.5. The IRAS PS were identified on transparent overlays made to the plate scale for each plate center, and the association of a spectrum with a given PS is usually unambiguous. In cases of doubt or offset, a comment is made. Note that there are some cases where the PSC gives an incorrect association on the basis of position, and the correct association is with a faint, uncatalogued M star. (3 data files).

  16. Experimental measurements and Monte Carlo calculations of dosimetric parameters of the IRA1-103Pd brachytherapy source.

    PubMed

    Sadeghi, Mahdi; Hosseini, S Hamed; Raisali, Gholamreza

    2008-10-01

    This work presents a brachytherapy source having (103)Pd adsorbed onto a cylindrical silver rod that has been developed by Agricultural, Medical and Industrial Research School for permanent implant applications. Dosimetric characteristics (dose-rate constant, radial dose function, anisotropy function and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task Group 43 (TG-43U1) recommendations. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located dosimeters and source in a reproducible fixed geometry providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-Particle (MCNP) code, version 4C was used to evaluate the dose-rate distributions around this model (103)Pd source in water and Perspex phantoms. The Monte Carlo calculated dose-rate constant of the IRA1-(103)Pd source in water was found equal to Lambda=0.669 cGy/h/U with approximate uncertainties of +/-0.1%. The anisotropy function, F(r, theta), and the radial dose function, g(L)(r), of the IRA1-(103)Pd source were also measured in Perspex phantom and calculated in both Perspex and liquid water phantom. PMID:18387806

  17. Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-{sup 103}Pd brachytherapy source

    SciTech Connect

    Sadeghi, Mahdi; Raisali, Gholamreza; Hosseini, S. Hamed; Shavar, Arzhang

    2008-04-15

    This article presents a brachytherapy source having {sup 103}Pd adsorbed onto a cylindrical silver rod that has been developed by the Agricultural, Medical, and Industrial Research School for permanent implant applications. Dosimetric characteristics (radial dose function, anisotropy function, and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task group 43 (TG-43U1) recommendations. Monte Carlo simulations were used to calculate the dose rate constant. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located the dosimeters and the source in a reproducible fixed geometry, providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-particle (MCNP) code, version 4C simulation techniques have been used to evaluate the dose-rate distributions around this model {sup 103}Pd source in water and Perspex phantoms. The Monte Carlo calculated dose rate constant of the IRA-{sup 103}Pd source in water was found to be 0.678 cGy h{sup -1} U{sup -1} with an approximate uncertainty of {+-}0.1%. The anisotropy function, F(r,{theta}), and the radial dose function, g(r), of the IRA-{sup 103}Pd source were also measured in a Perspex phantom and calculated in both Perspex and liquid water phantoms.

  18. SIMBA survey of southern high-mass star forming regions. I. Physical parameters of the 1.2 mm/IRAS sources

    NASA Astrophysics Data System (ADS)

    Faúndez, S.; Bronfman, L.; Garay, G.; Chini, R.; Nyman, L.-Å.; May, J.

    2004-10-01

    We report the results of a 1.2 mm continuum emission survey toward 146 IRAS sources thought to harbour high-mass star forming regions. The sources have FIR colors typical of UCHII regions and were detected in the CS(2->1) line survey of Bronfman et al. (\\cite{bnm}). Regions of 15 arcmin × 10 arcmin, centered on each IRAS source, were mapped with an angular resolution of ˜24 arcsec, using the SIMBA array on the SEST telescope. 1.2 mm emission was detected toward all IRAS sources. We find that the dust cores associated with these sources have typical sizes of 0.4 pc and masses of 5× 103 M⊙. Dust temperatures and luminosities, derived from the SED, are typically 32 K and 2.3 × 105 L⊙. Table 1 and Figs. 6 to 23 are only available in electronic form at http://www.edpsciences.org

  19. An examination of possible solar wind sources for a sudden brightening of Comet IRAS-Araki-Alcock

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Luhmann, J. G.; Baker, D. N.

    1987-01-01

    Terrestrial and near-earth measurements are examined in order to investigate possible solar wind sources for the sudden global brightenings noted in Comet IRAS-Araki-Alcock. These brightenings are not found to be associated with increases in the solar wind momentum flux, quantity of solar energetic particles, or solar activity, in contradiction to the proposal of Lutz and Wagner (1986). If a radial alignment of the IMF seen at IMP-8 after about 0800 UT was not responsible for the cometary brightening, then it is suggested that the brightening must have been intrinsic to the comet.

  20. Organic Chemistry of Southern Sources: Microwave Spectroscopy of Cha-MMS1 and IRAS 15194-5115

    NASA Technical Reports Server (NTRS)

    Cordiner, Martin; Charnley, Steven

    2011-01-01

    We report new spectra of molecule-rich sources in the southern hemisphere obtained using the 22-meter Mopra telescope. Spectra and maps are presented of organic molecules detected between 30 and 50 GHz in the young Class 0 protostar Chamaeleon MMS-1. The large abundances of polyynes, cyanopolyynes and methanol may be indicative of a warm carbon chemistry in the dense gas surrounding this protostar. Spectra are also presented from a 78-96 GHz scan of the carbon-rich AGB star IRAS 15194-5115, including new detections of HC5N, CCS and C13CH.

  1. Ground-based infrared observations of variable IRAS sources as candidates for late asymptotic giant branch stars

    NASA Technical Reports Server (NTRS)

    Kwok, Sun; Boreiko, R. T.; Hrivnak, Bruce J.

    1987-01-01

    Analysis of the color distribution of OH/IR stars and IRAS low-resolution spectra class 30 objects suggests the presence of a well-defined evolutionary sequence which is populated by late asymptotic giant branch (LAGB) stars. The paper reports ground-based identification and infrared photometry of 10 candidates of news LAGB stars. None of the selected sources are found to have optical counterparts, and eight of the 10 show a strong 10-micron silicate absorption feature. It is suggested that these stars represent an invisible extension of extreme Mira variables and are some of the most evolved stars observed to date.

  2. Searching for heavily obscured post-AGB stars and planetary nebulae. II. Near-IR observations of IRAS sources

    NASA Astrophysics Data System (ADS)

    Ramos-Larios, G.; Guerrero, M. A.; Suárez, O.; Miranda, L. F.; Gómez, J. F.

    2012-09-01

    The most massive AGB stars are expected to result in heavily obscured post-AGB stars, proto-PNe and PNe with highly axisymmetric morphologies. To investigate this evolutionary connection, we have selected a sample of 165 presumably obscured IRAS post-AGB star and PN candidates and obtained near-IR JHK images for 164 of them. These images, in conjunction with DSS, 2MASS, Spitzer GLIMPSE, MSX, AKARI, and IRAS archival data, have allowed us to identify the near-IR counterparts of 154 of these sources, providing reliable finding charts and coordinates. Near-IR narrow-band Brγ, H2, and K continuum images were acquired for 6 of these sources that were found to be resolved in near-IR JHK images. Among the extended post-AGB source and PN candidates, three are round and seven have bipolar morphologies. Five of the extended sources are ionized and may have thus entered the PN stage. We note that all extended sources with water maser emission have bipolar morphology. We have investigated the Galactic distribution of sources with the largest flux drop from the 9 μm AKARI band to the near-IR J band and found that the width of the distribution in Galactic latitude is consistent with those of bipolar PNe and DUPLEX (DUst-Prominent Longitudinally EXtended) sources. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (081.D-0812), observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, and on observations with AKARI, a JAXA project with the participation of ESA.

  3. CO STRUCTURE OF THE 21 {mu}m SOURCE IRAS 22272+5435: A SIGN OF A JET LAUNCH?

    SciTech Connect

    Nakashima, Jun-ichi; Kwok, Sun; Yung, Bosco H. K.; Zhang Yong; Koning, Nico; Volgenau, Nikolaus H.

    2012-11-01

    We report the results of radio interferometric observations of the 21 {mu}m source IRAS 22272+5435 in the CO J = 2-1 line. 21 {mu}m sources are carbon-rich objects in the post-asymptotic-giant-branch phase of evolution, which show an unidentified emission feature at 21 {mu}m. Since 21 {mu}m sources usually also have circumstellar molecular envelopes, the mapping of CO emission from the envelope will be useful in tracing the nebular structure. From observations made with the Combined Array for Research in Millimeter-wave Astronomy, we find that a torus and spherical wind model can explain only part of the CO structure. An additional axisymmetric region created by the interaction between an invisible jet and ambient material is suggested.

  4. High luminance low etendue white light source using blue laser over static phosphor

    NASA Astrophysics Data System (ADS)

    Farooq, Tayyab; Qian, KeYuan

    2015-10-01

    A High Luminance White Light source for Etendue limited application has been demonstrated in this research paper by using blue InGaN laser diode beam over static source of phosphor Ce: YAG layer. Phosphor target has kept static because moving phosphor target light output is not constant and uniform. Different color temperatures had been obtained by varying phosphor concentration and thickness of the layer. When laser beam has focused on phosphor target spot, it induced very high temperature at that spot area. Temperature induced in the layer by laser beam depends on the layer thickness. All the layer thickness, surface temperature, output light flux, efficiency, and light color temperature are interrelate with each other. Uniform laser beam distribution, surface temperature, laser spot size, phosphor layer thickness are successfully calculated. Luminous efficiency, light color temperature, flux, wavelength spectrum, and light output power of laser driven white light source had been successfully observed at different laser beam powers.

  5. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 6: The point source catalog declination range -50 deg greater than delta greater than -90 deg

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched January 26, 1983. During its 300-day mission, it surveyed over 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. This is Volume 6, The Point Source Catalog Declination Range -50 deg greater than delta greater than -90 deg.

  6. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 4: The point source catalog declination range 0 deg greater than delta greater than -30 deg

    SciTech Connect

    Not Available

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched 26 January 1983. During its 300-day mission, it surveyed over 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. This is Volume 4, The Point Source Catalog Declination Range 0 deg greater than delta greater than -30 deg.

  7. Young Stellar Cluster in the Vicinity of the IRAS 05137+3919 Source

    NASA Astrophysics Data System (ADS)

    Nikoghosyan, E. H.; Azatyan, N.

    2014-09-01

    84 PMS stellar objects are identified in a cluster located in the vicinity of IRAS 05137+3919 using the UKIDSS data base and Spitzer telescope (IRAC) images. The age of the cluster is 1.5-2.0 million years. Young stars are distributed nonuniformly in the cluster and form two subgroups. One is localized around the YSO CPM, which is a binary star, and the second contains a substantial number of objects with early spectral classes surrounded by gas-dust nebulae. The K luminosity functions of the PMS stars indicate that the cluster is at a distance of ~4.5 kpc. One of the components of CPM 15 appears to have Sp B3-B5 and is an Ae/Be Herbig star.

  8. Luminous Supersoft X-Ray Sources as Progenitors of Type Ia Supernovae

    NASA Technical Reports Server (NTRS)

    DiStefano, R.

    1996-01-01

    In some luminous supersoft X-ray sources, hydrogen accretes onto the surface of a white dwarf at rates more-or-less compatible with steady nuclear burning. The white dwarfs in these systems therefore have a good chance to grow in mass. Here we review what is known about the rate of Type la supernovae that may be associated with SSSS. Observable consequences of the conjecture that SSSs can be progenitors of Type Ia supernovae are also discussed.

  9. ROSAT observations of the luminous X-ray sources in M51

    NASA Technical Reports Server (NTRS)

    Marston, A. P.; Elmegreen, D.; Elmegreen, B.; Forman, W.; Jones, C.; Flanagan, K.

    1995-01-01

    Our analysis of a 24 ks ROSAT Position Sensitive Proprtional Counter (PSPC) image of the interacting galaxies NGC 5194 (M51) and NGC 5195 shows that X-ray emission is distributed across the whole of NGC 5194. In addition to the diffuse emission and a bright nuclear region, eight individual sources were detected with 0.2-2.2 keV luminosities from 5 to 29 x 10(exp 38) ergs/s, more than 10 times higher than typical bright Galactic X-ray sources. The energy distribution of the luminous sources can be characterized by bremsstrahlung spectra with temperatures around 1 keV and low-energy absorption exceeding that expected from our Galaxy. Two sources lie in an inner spiral arm, while five lie along the outer edges of the outer spiral arms. Four sources (R1, R2, R4, R6) lie in or near regions of recent star formation as indicated by H II regions or CO emission from molecular clouds. However, for three of the X-ray sources which fall on the outer edge of the spiral arms (R3, R7, and R8), there is little or no associated CO or H alpha emission. We discuss the origin of the luminous X-ray sources as possibly arising from either massive black holes in binary star systems, supernova remnants, or hot gas associated with star forming regions.

  10. Galaxy evolution and large-scale structure in the far-infrared. II - The IRAS faint source survey

    NASA Astrophysics Data System (ADS)

    Lonsdale, Carol J.; Hacking, Perry B.; Conrow, T. P.; Rowan-Robinson, M.

    1990-07-01

    The new IRAS Faint Source Survey data base is used to confirm the conclusion of Hacking et al. (1987) that the 60 micron source counts fainter than about 0.5 Jy lie in excess of predictions based on nonevolving model populations. The existence of an anisotropy between the northern and southern Galactic caps discovered by Rowan-Robinson et al. (1986) and Needham and Rowan-Robinson (1988) is confirmed, and it is found to extend below their sensitivity limit to about 0.3 Jy in 60 micron flux density. The count anisotropy at f(60) greater than 0.3 can be interpreted reasonably as due to the Local Supercluster; however, no one structure accounting for the fainter anisotropy can be easily identified in either optical or far-IR two-dimensional sky distributions. The far-IR galaxy sky distributions are considerably smoother than distributions from the published optical galaxy catalogs. It is likely that structure of the large size discussed here have been discriminated against in earlier studies due to insufficient volume sampling.

  11. Galaxy evolution and large-scale structure in the far-infrared. II - The IRAS faint source survey

    NASA Technical Reports Server (NTRS)

    Lonsdale, Carol J.; Hacking, Perry B.; Conrow, T. P.; Rowan-Robinson, M.

    1990-01-01

    The new IRAS Faint Source Survey data base is used to confirm the conclusion of Hacking et al. (1987) that the 60 micron source counts fainter than about 0.5 Jy lie in excess of predictions based on nonevolving model populations. The existence of an anisotropy between the northern and southern Galactic caps discovered by Rowan-Robinson et al. (1986) and Needham and Rowan-Robinson (1988) is confirmed, and it is found to extend below their sensitivity limit to about 0.3 Jy in 60 micron flux density. The count anisotropy at f(60) greater than 0.3 can be interpreted reasonably as due to the Local Supercluster; however, no one structure accounting for the fainter anisotropy can be easily identified in either optical or far-IR two-dimensional sky distributions. The far-IR galaxy sky distributions are considerably smoother than distributions from the published optical galaxy catalogs. It is likely that structure of the large size discussed here have been discriminated against in earlier studies due to insufficient volume sampling.

  12. Galaxy evolution and large-scale structure in the far-infrared. II. The IRAS faint source survey

    SciTech Connect

    Lonsdale, C.J.; Hacking, P.B.; Conrow, T.P.; Rowan-Robinson, M. Queen Mary College, London )

    1990-07-01

    The new IRAS Faint Source Survey data base is used to confirm the conclusion of Hacking et al. (1987) that the 60 micron source counts fainter than about 0.5 Jy lie in excess of predictions based on nonevolving model populations. The existence of an anisotropy between the northern and southern Galactic caps discovered by Rowan-Robinson et al. (1986) and Needham and Rowan-Robinson (1988) is confirmed, and it is found to extend below their sensitivity limit to about 0.3 Jy in 60 micron flux density. The count anisotropy at f(60) greater than 0.3 can be interpreted reasonably as due to the Local Supercluster; however, no one structure accounting for the fainter anisotropy can be easily identified in either optical or far-IR two-dimensional sky distributions. The far-IR galaxy sky distributions are considerably smoother than distributions from the published optical galaxy catalogs. It is likely that structure of the large size discussed here have been discriminated against in earlier studies due to insufficient volume sampling. 105 refs.

  13. Chandra Discovery of Luminous Supersoft X-Ray Sources in M81

    NASA Technical Reports Server (NTRS)

    Swartz, Douglas A.; Ghosh, Kajal K.; Sulimanov, Valery; Tennant, Allyn F.; Wu, Kinwah; Six, N. Frank (Technical Monitor)

    2002-01-01

    A Chandra ACIS-S imaging observation of the nearby galaxy M81 (NGC 3031) reveals 9 luminous soft X-ray sources. The local environments, X-ray spectral properties, and X-ray light curves of the sources are presented and discussed in the context of prevailing physical models for supersoft sources. It is shown that the sample falls within expectations based on population synthesis models taken from the literature though the high observed luminosities (L approx.2e36 to approx.3e38 ergs in the 0.2--2.0-keV band) and equivalent blackbody temperatures (T approx.40 to 80 eV) place the brightest detected M81 objects at the high luminosity end of the class of supersoft sources defined by previous ROSAT and Einstein studies of nearby galaxies. This is interpreted as a natural consequence of the higher sensitivity of Chandra to hotter and more luminous systems. Most of the sources can be explained as canonical supersoft sources, secreting white dwarfs powered by steady surface nuclear burning, with X-ray spectra well-fit by hot white dwarf local thermodynamic equilibrium atmosphere models. An exceptionally bright source is scrutinized in greater detail as its estimated barometric luminosity, L approx. 1.5e39 ergs, greatly exceeds theoretical estimates for supersoft sources. This source may be beyond the stability limit and undergoing a phase of mass outflow under extreme conditions. Alternatively, a model in which the observed X-ray spectrum arises from an accretion disk around a blacklists of mass approx.1200/sqrt(cosi) solar masses (viewed at an inclination angle 1) cannot be excluded.

  14. Total luminous flux measurement for flexible surface sources with an integrating sphere photometer

    NASA Astrophysics Data System (ADS)

    Yu, Hsueh-Ling; Liu, Wen-Chun

    2014-01-01

    Applying an integrating sphere photometer for total luminous flux measurement is a widely used method. However, the measurement accuracy depends on the spatial uniformity of the integrating sphere, especially when the test sample has a different light distribution from that of the standard source. Therefore, spatial correction is needed to eliminate the effect caused by non-uniformity. To reduce the inconvenience of spatial correction but retain the measurement accuracy, a new type of working standard is designed for flexible and curved surface sources. Applying this new type standard source, the measurement deviation due to different orientations is reduced by an order of magnitude compared with using a naked incandescent lamp as the standard source.

  15. A high-significance measurement of correlation between unresolved IRAS sources and optically-selected galaxy clusters

    SciTech Connect

    Hincks, Adam D.; Hajian, Amir; Addison, Graeme E. E-mail: ahajian@cita.utoronto.ca

    2013-05-01

    We cross-correlate the 100 μm Improved Reprocessing of the IRAS Survey (IRIS) map and galaxy clusters at 0.1 < z < 0.3 in the maxBCG catalogue taken from the Sloan Digital Sky Survey, measuring an angular cross-power spectrum over multipole moments 150 < l < 3000 at a total significance of over 40σ. The cross-spectrum, which arises from the spatial correlation between unresolved dusty galaxies that make up the cosmic infrared background (CIB) in the IRIS map and the galaxy clusters, is well-fit by a single power law with an index of −1.28±0.12, similar to the clustering of unresolved galaxies from cross-correlating far-infrared and submillimetre maps at longer wavelengths. Using a recent, phenomenological model for the spectral and clustering properties of the IRIS galaxies, we constrain the large-scale bias of the maxBCG clusters to be 2.6±1.4, consistent with existing analyses of the real-space cluster correlation function. The success of our method suggests that future CIB-optical cross-correlations using Planck and Herschel data will significantly improve our understanding of the clustering and redshift distribution of the faint CIB sources.

  16. Infrared astronomy after IRAS

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.; Thompson, R. I.; Werner, M. W.; Witteborn, F. C.; Becklin, E. E.

    1986-01-01

    The development of infrared astronomy in the wake of IRAS is discussed. Attention is given to an overview of next generation infrared telescope technology, with emphasis on the Space Infrared Telescope Facility (SIRTF) which has been built to replace IRAS in the 1990s. Among the instruments to be included on SIRTF are: a wide-field high-resolution camera covering the infrared range 3-30 microns with large arrays of detectors; an imaging photometer operating in the range 3-700 microns; and a spectrograph covering the range 2.5-200 microns with resolutions of 2 and 0.1 percent. Observational missions for the SIRTF are proposed in connection with: planetary formation; star formation; cosmic energy sources; active galactic nuclei; and quasars.

  17. Luminous radio-quiet sources in the W3(MAIN) cloud core

    NASA Technical Reports Server (NTRS)

    Wynnwilliams, C. Gareth; Ladd, E. F.; Deane, James R.; Sanders, D. B.

    1994-01-01

    We have resolved 450 micrometer and 800 micrometer emission from the W3(Main) star forming region into three major peaks, using 8 inch - 14 inch beams with the James Clerk Maxwell Telescope on the summit of Mauna Kea. One of the submillimeter sources is identified with W3 - IRS5, a well-known candidate protostar. However, to our surprise, we find that none of the submillimeter peaks coincides with any of the prominent compact HII regions in the area. We estimate that the three submillimeter sources together contribute 30-50 percent of the total bolometric luminosity of the region, and speculate that the contribution of luminous radio-quiet sources to the total luminosity of HII region/molecular cloud complexes may be larger than is often assumed.

  18. IRAS comet observations - The continuing saga

    NASA Technical Reports Server (NTRS)

    Walker, R. G.; Aumann, H. H.

    1990-01-01

    IRAS observations of comets include photometry, spectroscopy, and multiple wavelength imagery. The large beam of the IRAS detector array, which was well suited to detect faint extended emissions of cometary origin, has produced a large data set that is complex to analyze. Although some preliminary results of the IRAS comet photometry have been published, definitive analysis must explicitly account for the convolution of the emission source with the nonuniform spatial response of the detector array. This paper reviews the progress made toward the production and subsequent analysis of instrument-free comet images, and presents the current state of the art IRAS images of comet Kopff.

  19. The IRAS Minor Planet Survey

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.; Veeder, Glenn J.; Fowler, John W.; Chillemi, Joseph R.

    1992-01-01

    This report documents the program and data used to identify known asteroids observed by the Infrared Astronomical Satellite (IRAS) and to compute albedos and diameters from their IRAS fluxes. It also presents listings of the results obtained. These results supplant those in the IRAS Asteroid and Comet Survey, 1986. The present version used new and improved asteroid orbital elements for 4679 numbered asteroids and 2632 additional asteroids for which at least two-opposition elements were available as of mid-1991. It employed asteroid absolute magnitudes on the International Astronomical Union system adopted in 1991. In addition, the code was modified to increase the reliability of associating asteroids with IRAS sources and rectify several shortcomings in the final data products released in 1986. Association reliability was improved by decreasing the position difference between an IRAS source and a predicted asteroid position required for an association. The shortcomings addressed included the problem of flux overestimation for low SNR sources and the systematic difference in albedos and diameters among the three wavelength bands (12, 25, and 60 micrometers). Several minor bugs in the original code were also corrected.

  20. An infrared sky model based on the IRAS point source data

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Walker, Russell; Wainscoat, Richard; Volk, Kevin; Walker, Helen; Schwartz, Deborah

    1990-01-01

    A detailed model for the infrared point source sky is presented that comprises geometrically and physically realistic representations of the galactic disk, bulge, spheroid, spiral arms, molecular ring, and absolute magnitudes. The model was guided by a parallel Monte Carlo simulation of the Galaxy. The content of the galactic source table constitutes an excellent match to the 12 micrometer luminosity function in the simulation, as well as the luminosity functions at V and K. Models are given for predicting the density of asteroids to be observed, and the diffuse background radiance of the Zodiacal cloud. The model can be used to predict the character of the point source sky expected for observations from future infrared space experiments.

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  2. The Ultra-Luminous X-ray Source Population from the Chandra Archive of Galaxies

    NASA Technical Reports Server (NTRS)

    Swartz, Douglas A.; Ghosh, Kajal K.; Tennant, Allen F.; Wu, Kinwah

    2004-01-01

    One hundred fifty-four discrete non-nuclear Ultra-Luminous X-ray (ULX) sources, with spectroscopically-determined intrinsic X-ray luminosities greater than 1 e39 ergs/s, are identified in 82 galaxies observed with Chandra's Advanced CCD Imaging Spectrometer. Source positions, X-ray luminosities, and spectral and timing characteristics are tabulated. Statistical comparisons between these X-ray properties and those of the weaker discrete sources in the same fields (mainly neutron star and stellar-mass black hole binaries) are made. Sources above approximately le38 ergs per second display similar spatial, spectral, color, and variability distributions. In particular, there is no compelling evidence in the sample for a new and distinct class of X-ray object such as the intermediate-mass black holes. 83% of ULX candidates have spectra that can be described as absorbed power laws with index = 1.74 and column density = 2.24e21 l per square centimeter, or approximately 5 times the average Galactic column. About 20% of the ULX's have much steeper indices indicative of a soft, and likely thermal, spectrum. The locations of ULXs in their host galaxies are strongly peaked towards their galaxy centers. The deprojected radial distribution of the ULX candidates is somewhat steeper than an exponential disk, indistinguishable from that of the weaker sources. About 5--15% of ULX candidates are variable during the Chandra observations (which average 39.5 ks). Comparison of the cumulative X-ray luminosity functions of the ULXs to Chandra Deep Field results suggests approximately 25% of the sources may be background objects including 14% of the ULX candidates in the sample of spiral galaxies and 44% of those in elliptical galaxies implying the elliptical galaxy ULX population is severely compromised by background active galactic nuclei. Correlations with host galaxy properties confirm the number and total X-ray luminosity of the ULXs are associated with recent star formation

  3. Luminous Infrared Sources in the Local Group: Identifying the Missing Links in Massive Star Evolution

    NASA Astrophysics Data System (ADS)

    Britavskiy, N.; Bonanos, A. Z.; Mehner, A.

    2015-01-01

    We present the first systematic survey of dusty massive stars (RSGs, LBVs, sgB[e]) in nearby galaxies, with the goal of understanding their importance in massive star evolution. Using the fact that these stars are bright in mid-infrared colors due to dust, we provide a technique for selecting and identifying dusty evolved stars based on the results of Bonanos et al. (2009, 2010), Britavskiy et al. (2014), and archival Spitzer/IRAC photometry. We present the results of our spectroscopic follow-up of luminous infrared sources in the Local Group dwarf irregular galaxies: Pegasus, Phoenix, Sextans A and WLM. The survey aims to complete the census of dusty massive stars in the Local Group.

  4. Accretion mode of the Ultra-Luminous X-ray source M82 X-2

    NASA Astrophysics Data System (ADS)

    Karino, S.; Miller, J. C.

    2016-05-01

    Periodic pulsations have been found in emission from the ultra-luminous X-ray source (ULX) M82 X-2, strongly suggesting that the emitter is a rotating neutron star rather than a black hole. However, the radiation mechanisms and accretion mode involved have not yet been clearly established. In this paper, we examine the applicability to this object of standard accretion modes for high mass X-ray binaries (HMXBs). We find that spherical wind accretion, which drives OB-type HMXBs, cannot apply here but that there is a natural explanation in terms of an extension of the picture for standard Be-type HMXBs. We show that a neutron star with a moderately strong magnetic field, accreting from a disc-shaped wind emitted by a Be-companion, could be compatible with the observed relation between spin and orbital period. A Roche lobe overflow picture is also possible under certain conditions.

  5. IRAS 14348-1447, an ultraluminous pair of colliding, gas-rich galaxies - The birth of a quasar?

    NASA Technical Reports Server (NTRS)

    Sanders, D. B.; Soifer, B. T.; Scoville, N. Z.

    1988-01-01

    Ground-baed observations of the object IRAS 14348-1447, which was discovered with the Infrared Astronomical Satellite, show that it is an extremely luminous colliding galaxy system that emits more than 95 percent of its energy at FIR wavelengths. IRAS 14348-1447, which is receeding from the sun at 8 percent of the speed of light, has a bolometric luminosity more than 100 times larger than that of the Galaxy, and is therefore as luminous as optical quasars. New optical, infrared, and spectroscopic measurements suggest that the dominant luminosity source is a dust-enshrouded quasar. The fuel for the intense activity is an enormous supply of molecular gas. Carbon monoxide emission has been detected at a wavelength of 2.6 millimeters by means of a new, more sensitive receiver recently installed on the 12-meter telescope of the National Radio Astronomy Observatory. IRAS 14348-1447 is the most distant and luminous source of carbon monoxide line emission yet detected.

  6. IRAS 14348-1447, an Ultraluminous Pair of Colliding, Gas-Rich Galaxies: The Birth of a Quasar?

    PubMed

    Sanders, D B; Scoville, N Z; Soifer, B T

    1988-02-01

    Ground-based observations of the object IRAS 14348-1447, which was discovered with the Infrared Astronomical Satellite, show that it is an extremely luminous colliding galaxy system that emits more than 95 percent of its energy at far-infrared wavelengths. IRAS 14348-1447, which is receeding from the sun at 8 percent of the speed of light, has a bolometric luminosity more than 100 times larger than that of our galaxy, and is therefore as luminous as optical quasars. New optical, infrared, and spectroscopic measurements suggest that the dominant luminosity source is a dustenshrouded quasar. The fuel for the intense activity is an enormous supply of molecular gas. Carbon monoxide emission has been detected at a wavelength of 2.6 millimeters by means of a new, more sensitive receiver recently installed on the 12-meter telescope of the National Radio Astronomy Observatory. IRAS 14348-1447 is the most distant and luminous source of carbon monoxide line emission yet detected. The derived mass of interstellar molecular hydrogen is 6 x 10(10) solar masses. This value is approximately 20 times that of the molecular gas content of the Milky Way and is similar to the largest masses of atomic hydrogen found in galaxies. A large mass of molecular gas may be a prerequisite for the formation of quasars during strong galactic collisions. PMID:17759060

  7. ULTRA-LUMINOUS X-RAY SOURCES IN THE MOST METAL POOR GALAXIES

    SciTech Connect

    Prestwich, A. H.; Zezas, A.; Jackson, F.; Tsantaki, Maria; Roberts, T. P.; Foltz, R.; Linden, T.; Kalogera, V.

    2013-06-01

    Ultra-luminous X-ray sources (ULX) are X-ray binaries with L{sub x} >10{sup 39} erg s{sup -1}. The most spectacular examples of ULX occur in starburst galaxies and are now understood to be young, luminous high mass X-ray binaries. The conditions under which ULX form are poorly understood, but recent evidence suggests they may be more common in low metallicity systems. Here we investigate the hypothesis that ULX form preferentially in low metallicity galaxies by searching for ULX in a sample of extremely metal poor galaxies (XMPG) observed with the Chandra X-Ray Observatory. XMPG are defined as galaxies with log(O/H) + 12 < 7.65, or less than 5% solar. These are the most metal-deficient galaxies known, and a logical place to find ULX if they favor metal poor systems. We compare the number of ULX (corrected for background contamination) per unit of star formation (N{sub ULX}(SFR)) in the XMPG sample with N{sub ULX}(SFR) in a comparison sample of galaxies with higher metallicities taken from the Spitzer Infrared Galaxy Sample. We find that ULX occur preferentially in the metal poor sample with a formal statistical significance of 2.3{sigma}. We do not see strong evidence for a trend in the formation of ULX in the high metallicity sample: above 12+log(O/H) {approx} 8.0 the efficiency of ULX production appears to be flat. The effect we see is strongest in the lowest metallicity bin. We discuss briefly the implications of these results for the formation of black holes in low metallicity gas.

  8. OPTICAL STUDY OF THE HYPER-LUMINOUS X-RAY SOURCE 2XMM J011942.7+032421

    SciTech Connect

    Gutiérrez, Carlos M.; Moon, Dae-Sik

    2014-12-10

    We present the identification and characterization of the optical counterpart to 2XMM J011942.7+032421, one of the most luminous and distant ultra-luminous X-ray sources (ULXs). The counterpart is located near a star-forming region in a spiral arm of the galaxy NGC 470 with u, g, and r magnitudes of 21.53, 21.69, and 21.71 mag, respectively. The luminosity of the counterpart is much larger than that of a single O-type star, indicating that it may be a stellar cluster. Our optical spectroscopic observations confirm the association of the X-ray source and the optical counterpart with its host galaxy NGC 470, which validates the high, ≳10{sup 41} erg s{sup -1}, X-ray luminosity of the source. Its optical spectrum is embedded with numerous emission lines, including H recombination lines, metallic forbidden lines, and more notably the high-ionization He II (λ4686) line. That line shows a large velocity dispersion of ≅410 km s{sup -1}, consistent with the existence of a compact (<5 AU) highly ionized accretion disk rotating around the central X-ray source. The ∼1.4 × 10{sup 37} erg s{sup -1} luminosity of the He II line emission makes the source one of the most luminous ULXs in that emission. This, together with the high X-ray luminosity and the large velocity dispersion of the He II emission, suggests that the source is an ideal candidate for more extensive follow-up observations for understanding the nature of hyper-luminous X-ray sources, a more luminous subgroup of ULXs, and more likely candidates for intermediate-mass black holes.

  9. XMM-Newton observations of three interacting luminous infrared galaxies

    SciTech Connect

    Mudd, Dale; Mathur, Smita; Guainazzi, Matteo; Piconcelli, Enrico; Nicastro, Fabrizio; Bianchi, Stefano; Komossa, S.; Vignali, Cristian; Lanzuisi, Giorgio; Fiore, Fabrizio; Maiolino, Roberto

    2014-05-20

    We investigate the X-ray properties of three interacting luminous infrared galaxy systems. In one of these systems, IRAS 18329+5950, we resolve two separate sources. A second and third source, IRAS 19354+4559 and IRAS 20550+1656, have only a single X-ray source detected. We compare the observed emission to point-spread function (PSF) profiles and determine that they are all consistent with the PSF, albeit with large uncertainties for some of our sources. We then model the spectra to determine soft (0.5-2 keV) and hard (2-10 keV) luminosities for the resolved sources and compare these to relationships found in the literature between infrared and X-ray luminosities for starburst galaxies. We obtain luminosities (0.5-10 keV) ranging from 1.7 to 7.3 × 10{sup 41} erg s{sup –1} for our systems. These X-ray luminosities are consistent with predictions for star-formation-dominated sources and thus are most likely due to starbursts, but we cannot conclusively rule out active galactic nuclei.

  10. LARGE HIGHLY IONIZED NEBULAE AROUND ULTRA-LUMINOUS X-RAY SOURCES

    SciTech Connect

    Moon, Dae-Sik; Shariff, Jamil A.; Harrison, Fiona A.; Cenko, S. Bradley E-mail: shariff@astro.utoronto.ca E-mail: cenko@astro.berkeley.edu

    2011-04-20

    We present the results of deep optical spectroscopic observations using the LRIS spectrograph on the Keck I 10 m telescope of three ultra-luminous X-ray sources (ULXs): Ho IX X-1, M81 X-6, and Ho II X-1. Our observations reveal the existence of large (100-200 pc diameter) highly ionized nebulae, identified by diffuse He II {lambda}4686 emission, surrounding these sources. Our results are the first to find highly ionized nebulae of this extent, and the detection in all three objects indicates this may be a common feature of ULXs. In addition to the extended emission, Ho IX X-1 has an unresolved central component containing about one-third of the total He II flux, with a significant velocity dispersion of {approx_equal}370 km s {sup -1}, suggestive of the existence of a photoionized accretion disk or an extremely hot early-type stellar counterpart. Most of the He II emission appears to be surrounded by significantly more extended H{beta} emission, and the intensity ratios between the two lines, which range from 0.12 to 0.33, indicate that photoionization is the origin of the He II emission. Sustaining these extended nebulae requires substantial X-ray emission, in the range {approx}10{sup 39}-10{sup 40} erg s {sup -1}, comparable to the measured X-ray luminosities of the sources. This favors models where the X-ray emission is isotropic, rather than beamed, which includes the interpretation that ULXs harbor intermediate-mass black holes.

  11. Relativistic radiative transfer in a moving stratus irradiated by a luminous flat source

    NASA Astrophysics Data System (ADS)

    Fukue, Jun

    2015-06-01

    Relativistic radiative transfer in a geometrically thin stratus (sheet-like gaseous cloud with finite optical depth), which is moving at a relativistic speed around a luminous flat source, such as accretion disks, and is irradiated by the source, is examined under the special relativistic treatment. Incident radiation is aberrated and Doppler-shifted when it is received by the stratus, and emitted radiation is also aberrated and Doppler-shifted when it leaves the stratus. Considering these relativistic effects, we analytically obtain the emergent intensity as well as other radiative quantities in the purely scattering case for both infinite and finite strati. We mainly consider the frequency-integrated case, but also briefly show the frequency-dependent one. We also solve the relativistic radiative transfer equation numerically, and compare the results with the analytical solutions. In the infinite stratus, the mean intensity in the comoving and inertial frames decreases and becomes constant, as the stratus speed increases. The flux in the comoving frame decreases exponentially with the optical depth. The emergent intensity decreases as the speed increases, since the incident photons are redshifted at the bottom-side of the stratus. In the finite stratus, the mean intensity in the comoving and inertial frames quickly increases in the top-side region due to the aberrated photons. The flux in the comoving frame is positive in the range of 0 < β ≤ 0.4, while it becomes negative for β ≳ 0.5. The behavior of the emergent intensity is similar to that of the infinite case, although there is an irradiation effect caused by the aberrated photons.

  12. PATCHY ACCRETION DISKS IN ULTRA-LUMINOUS X-RAY SOURCES

    SciTech Connect

    Miller, J. M.; Bachetti, M.; Barret, D.; Webb, N. A.; Harrison, F. A.; Walton, D. J.; Rana, V.; Fabian, A. C.

    2014-04-10

    The X-ray spectra of the most extreme ultra-luminous X-ray sources—those with L ≥ 10{sup 40} erg s{sup –1}—remain something of a mystery. Spectral roll-over in the 5-10 keV band was originally detected in the deepest XMM-Newton observations of the brightest sources; this is confirmed in subsequent NuSTAR spectra. This emission can be modeled via Comptonization, but with low electron temperatures (kT{sub e} ≅ 2 keV) and high optical depths (τ ≅ 10) that pose numerous difficulties. Moreover, evidence of cooler thermal emission that can be fit with thin disk models persists, even in fits to joint XMM-Newton and NuSTAR observations. Using NGC 1313 X-1 as a test case, we show that a patchy disk with a multiple temperature profile may provide an excellent description of such spectra. In principle, a number of patches within a cool disk might emit over a range of temperatures, but the data only require a two-temperature profile plus standard Comptonization, or three distinct blackbody components. A mechanism such as the photon bubble instability may naturally give rise to a patchy disk profile, and could give rise to super-Eddington luminosities. It is possible, then, that a patchy disk (rather than a disk with a standard single-temperature profile) might be a hallmark of accretion disks close to or above the Eddington limit. We discuss further tests of this picture and potential implications for sources such as narrow-line Seyfert-1 galaxies and other low-mass active galactic nuclei.

  13. Kinematics of the ionized gas around ultra-luminous X-ray sources in nearby spiral galaxies.

    NASA Astrophysics Data System (ADS)

    Fuentes-Carrera, Isaura L.; Sánchez Cruces, Mónica; Rosado, Margarita; Benitez-Benitez, Claudia; Salinas-Martínez, Alfredo; Aguilera, Verónica; Cruz-Reyes, Mariana

    2016-07-01

    We present scanning Fabry-Perot observations of the ionized gas surrounding ultra-luminous X-ray sources in four nearby spiral galaxies. We identify non-circular motions that may be associated with either isotropically or beamed expanding gas. Most of the sources observed show asymmetrical distribution of the ionized emission as well as asymmetrical distribution of gas motions. We also study the location of these sources in the context of the whole galaxy in different wavelengths. This work is part of an analysis to determine the nature of these sources and their correlation (if any) with the kinematics of host galaxy.

  14. The IRAS PSC/FSC Combined Catalogue

    NASA Astrophysics Data System (ADS)

    Abrahamyan, H. V.; Mickaelian, A. M.; Knyazyan, A. V.

    2015-04-01

    Optical identifications of a few thousands of IRAS sources showed that IRAS Point Source and IRAS Faint Source catalogues (PSC and FSC, respectively) contain many quasars and active galactic nuclei, late-type stars, planetary nebulae, variables, etc. To increase the efficiency of using IRAS PSC and FSC, which contain a lot of common sources, one needs a joint catalogue of all IRAS point sources with improved data based on both catalogues. However, cross-correlation of the catalogues is not so easy, as the association of many sources is relative, and not always it is obvious, whose source from one catalogue corresponds to the other one in the second catalogue. This problem exists in case of using standard cross-correlation tools like VizieR. Therefore, we have created a tool for cross-matching astronomical catalogues and we have applied it to IRAS PSC and FSC. Using this tool we have carried out identifications with a search radius corresponding to 3 σ of errors for each source individually rather than a standard radius for all sources. As a result, we obtained 73,770 associations. We showed that in case of cross-correlation of these catalogues by VizieR, we had to take 161.95 arcseconds radius not to lose any association; however, in this case a lot of false associations appear for many sources. In addition, we have made cross-correlations with AKARI-IRC, AKARI-FIS and WISE catalogues. As a result we created a catalogue with high positional accuracy and with 17 photometric measurements from 1.25 to 160 μm range, providing a detailed catalogue for IRAS point sources.

  15. An IRAS Hires study of low mass star formation in the Taurus molecular ring

    NASA Technical Reports Server (NTRS)

    Terebey, Susan; Surace, Jason A.

    1994-01-01

    The Taurus molecular cloud supposedly has no star clusters but only isolated star formation. However, the Infrared Astronomical Satellite (IRAS) shows us that a small star cluster is currently forming in Taurus. Most of the sources are deeply embedded and are probably low-mass protostars. We use High Resolution (HiRes) images of the IRAS data from the Infrared Processing and Analysis Center (IPAC) to look for additional infrared members of the cluster. We also investigate the question of whether the infrared emission matches predictions for protostellar sources by examining whether the dust emission is resolved on scales of one arcminute (approx. 10(exp 17) cm). With the exception of a luminous visible star, HD 29647, we find that the sources L1527, TMC1A, TMC1, TMC1C, tMR1, and IC2087 are unresolved in the HiRes images at 60 microns. Further analysis of IC2087 shows that it is unresolved at all four IRAS wavelengths.

  16. Accretion Disks Driven by External Radiation Drag around Central Luminous Sources

    NASA Astrophysics Data System (ADS)

    Fukue, Jun; Umemura, Masayuki

    1995-08-01

    Accretion disks/disk accretions (beta -disks) driven by the external radiation drag exerted by a central luminous source are presented under the steady and subrelativistic approximations. In a cold regime, where the gravity of the central object, the radiation force, and the radiation drag are included, but the pressure-gradient force is neglected, we find steady solutions such that the infalling velocity v_r is inversely proportional to radius r far from the center and becomes constant near to the center, while the rotation velocity v_ϕ is Keplerian far from the center and drops exponentially near to the center. In a warm regime, where the effect of the gas pressure is also taken into account, we find steady transonic solutions such that a flow accreting subsonically and rotating with the Keplerian velocity far from the center becomes, after passing a sonic point, an almost radially accreting supersonic flow with no angular momentum. Due to the effect of external radiation drag, the angular momentum of the gas is removed. In particular, it is quickly lost inside the characteristic radius r_0, which is expressed as r_0 = displaystyle (Gamma (2)/(1-Gamma )r_) g, where Gamma is the central luminosity normalized by the Eddington luminosity and r_g is the Schwarzschild radius of the central object. As a result, the nearly Keplerian rotating disk outside r_0 turns to a nearly radial flow inside r_0. Furthermore, in the vicinity of the central object the infall velocity attains a terminal value, at which the effective gravity is balanced by radiation drag. The terminal speed v_infty is found to be v_infty = - displaystyle (1-Gamma )/(2Gamma )c. Such accretion disks, where the angular momentum is removed via the external drag of radiation fields from the central source, are possible in several astrophysical contexts. For example, in the case of an X-ray burster the radiation density at the burst phases is very high in the inner region of the accretion disk, and therefore

  17. The IRAS view of the extragalactic sky

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.; Neugebauer, G.; Houck, J. R.

    1987-01-01

    The IR-observable characteristics of the extragalactic sky are reviewed, summarizing the results of recent studies based on the IRAS survey, which covers over 96 percent of the sky to about 500 mJy at 12, 25, and 60 microns and to about 1.5 Jy at 100 microns. The numerical and morphological data are described; possible mechanisms for the IR emission are discussed; and the object classes are considered separately. Consideration is given to spiral and disk galaxies, barred and ring galaxies, irregular and dwarf galaxies, blue compact galaxies, elliptical and S0 galaxies, AGN observations (BL Lacs and OVV quasars, Seyfert galaxies, and quasars), highly luminous IR galaxies, and the cosmological implications of the IRAS findings. Diagrams, graphs, and tables are provided.

  18. XMM-NEWTON OBSERVATIONS OF LUMINOUS SOURCES IN NEARBY GALAXIES NGC 4395, NGC 4736, AND NGC 4258

    SciTech Connect

    Akyuz, A.; Avdan, H.; Kayaci, S.; Ozel, M. E.; Sonbas, E.; Balman, S.

    2013-03-15

    We present the results of a study of non-nuclear discrete sources in a sample of three nearby spiral galaxies (NGC 4395, NGC 4736, and NGC 4258) based on XMM-Newton archival data supplemented with Chandra data for spectral and timing analyses. A total of 75 X-ray sources have been detected within the D{sub 25} regions of the target galaxies. The large collecting area of XMM-Newton makes the statistics sufficient to obtain spectral fitting for 16 (about 20%) of these sources. Compiling the extensive archival exposures available, we were able to obtain the detailed spectral shapes of diverse classes of point sources. We have also studied temporal properties of these luminous sources. Eleven of them are found to show short-term (less than 80 ks) variation while eight of them show long-term variation within factors of {approx}2-5 during a time interval of {approx}2-12 years. Timing analysis provides strong evidence that most of these sources are accreting X-ray binary systems. One source that has properties different from others was suspected to be a supernova remnant, and our follow-up optical observation confirmed this. Our results indicate that sources within the three nearby galaxies are showing a variety of source populations, including several ultraluminous X-ray sources, X-ray binaries, transients together with a super soft source, and a background active galactic nucleus candidate.

  19. Calcium transport in bovine rumen epithelium as affected by luminal Ca concentrations and Ca sources

    PubMed Central

    Schröder, Bernd; Wilkens, Mirja R; Ricken, Gundula E; Leonhard-Marek, Sabine; Fraser, David R; Breves, Gerhard

    2015-01-01

    The quantitative role of different segments of the gastrointestinal tract for Ca absorption, the respective mechanisms, and their regulation are not fully identified for ruminants, that is, cattle. In different in vitro experiments the forestomach wall has been demonstrated to be a major site for active Ca absorption in sheep and goats. In order to further clarify the role of the bovine rumen for Ca transport with special attention to luminal Ca concentrations, its ionic form, and pH, electrophysiological and unidirectional flux rate measurements were performed with isolated bovine rumen epithelial tissues. For Ca flux studies (Jms, Jsm) in vitro Ussing chamber technique was applied. Standard RT-PCR method was used to characterize TRPV6 and PMCA1 as potential contributors to transepithelial active Ca transport. At Ca concentrations of 1.2 mmol L−1 on both sides of the tissues, Jms were higher than Jsm resulting under some conditions in significant Ca net flux rates (Jnet), indicating the presence of active Ca transport. In the absence of an electrical gradient, Jnet could significantly be stimulated in the presence of luminal short-chain fatty acids (SCFAs). Increasing the luminal Ca concentrations up to 11.2 mmol L−1 resulted in significant increases in Jms without influencing Jsm. Providing Ca in its form as respective chloride, formate, or propionate salts there was no significant effect on Jms. No transcripts specific for Ca channel TRPV6 could be demonstrated. Our results indicate different mechanisms for Ca absorption in bovine rumen as compared with those usually described for the small intestines. PMID:26564067

  20. Calcium transport in bovine rumen epithelium as affected by luminal Ca concentrations and Ca sources.

    PubMed

    Schröder, Bernd; Wilkens, Mirja R; Ricken, Gundula E; Leonhard-Marek, Sabine; Fraser, David R; Breves, Gerhard

    2015-11-01

    The quantitative role of different segments of the gastrointestinal tract for Ca absorption, the respective mechanisms, and their regulation are not fully identified for ruminants, that is, cattle. In different in vitro experiments the forestomach wall has been demonstrated to be a major site for active Ca absorption in sheep and goats. In order to further clarify the role of the bovine rumen for Ca transport with special attention to luminal Ca concentrations, its ionic form, and pH, electrophysiological and unidirectional flux rate measurements were performed with isolated bovine rumen epithelial tissues. For Ca flux studies (Jms, Jsm) in vitro Ussing chamber technique was applied. Standard RT-PCR method was used to characterize TRPV6 and PMCA1 as potential contributors to transepithelial active Ca transport. At Ca concentrations of 1.2 mmol L(-1) on both sides of the tissues, Jms were higher than Jsm resulting under some conditions in significant Ca net flux rates (Jnet), indicating the presence of active Ca transport. In the absence of an electrical gradient, Jnet could significantly be stimulated in the presence of luminal short-chain fatty acids (SCFAs). Increasing the luminal Ca concentrations up to 11.2 mmol L(-1) resulted in significant increases in Jms without influencing Jsm. Providing Ca in its form as respective chloride, formate, or propionate salts there was no significant effect on Jms. No transcripts specific for Ca channel TRPV6 could be demonstrated. Our results indicate different mechanisms for Ca absorption in bovine rumen as compared with those usually described for the small intestines. PMID:26564067

  1. An Optical Study of Stellar and Interstellar Environments of Seven Luminous and Ultraluminous X-Ray Sources

    NASA Astrophysics Data System (ADS)

    Ramsey, Caitlin J.; Williams, Rosa M.; Gruendl, Robert A.; Chen, C.-H. Rosie; Chu, You-Hua; Wang, Q. Daniel

    2006-04-01

    We have studied the stellar and interstellar environments of two luminous X-ray sources and five ultraluminous X-ray sources (ULXs) in order to gain insight into their nature. Archival Hubble Space Telescope images were used to identify the optical counterparts of the ULXs Ho IX X-1 and NGC 1313 X-2, and to make photometric measurements of the local stellar populations of these and the luminous source IC 10 X-1. We obtained high-dispersion spectroscopic observations of the nebulae around these seven sources to search for He II λ4686 emission and to estimate the expansion velocities and kinetic energies of these nebulae. Our observations did not detect nebular He II emission from any source, with the exception of LMC X-1 this is either because we missed the He III regions or because the nebulae are too diffuse to produce He II surface brightnesses that lie within our detection limit. We compare the observed ionization and kinematics of the supershells around the ULXs Ho IX X-1 and NGC 1313 X-2 with the energy feedback expected from the underlying stellar population to assess whether additional energy contributions from the ULXs are needed. In both cases, we find insufficient UV fluxes or mechanical energies from the stellar population; thus these ULXs may be partially responsible for the ionization and energetics of their supershells. All seven sources that we studied are in young stellar environments, and six of them have optical counterparts with masses >~7 Msolar thus, these sources are most likely high-mass X-ray binaries.

  2. IRAS software analysis library

    NASA Technical Reports Server (NTRS)

    Domik, Gitta; Merkle, C. Scott

    1991-01-01

    The goal of this project was to collect 'research software' written in Interactive Data Language (IDL) to support analysis of data from the Infrared Astronomical Satellite (IRAS) and make it available to the larger community. 'Research Software' describes software created by researchers and staff for a specific research goal, but lacks sufficient documentation, easy to use interfaces, and rigorous debugging. Additionally, most of the IDL/IRAS code available needed to be ported to a (largely) hardware independent new version of IDL.

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  4. The Most Luminous Galaxies Found by WISE

    NASA Astrophysics Data System (ADS)

    Eisenhardt, Peter; Tsai, Chao-Wei; Wu, Jingwen; Griffith, Roger; Yan, Lin; Stern, Daniel; Stanford, Adam; Blain, Andrew; Benford, Dominic; Bridge, Carrie; Petty, Sara; Assef, Roberto; Donoso, Emilio; Lake, Sean

    2012-08-01

    NASA's Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at 3.4, 4.6, 12 and 22 (micron) (W1, W2, W3, and W4), reaching sensitivities hundreds of times deeper than IRAS. We have used WISE photometry to select an all-sky sample of objects which are extremely luminous. The objects are prominent in W4, but faint or undetected in W1 and W2 (W12drops). Followup spectroscopy shows that most of the sources have redshifts z>2. In combination with Herschel photometry, these redshifts lead to typical L_bol > 10^13 L_⊙, with ~10% exceeding 10^14 L_⊙. High resolution adaptive optics imaging shows these objects are typically unlensed. We request NOAO time to obtain redshifts and optical and near IR photometry of the complete all-sky sample of the brightest W12drops, all of which are in our Herschel program. This will fulfill the primary WISE objective of finding the most extreme luminous IR galaxies in the Universe. These superlative objects will be the most fruitful for detailed studies of the physics of star formation, AGN fueling, and feedback in the most active galaxies.

  5. Infalling–Rotating Motion and Associated Chemical Change in the Envelope of IRAS 16293–2422 Source A Studied with ALMA

    NASA Astrophysics Data System (ADS)

    Oya, Yoko; Sakai, Nami; López-Sepulcre, Ana; Watanabe, Yoshimasa; Ceccarelli, Cecilia; Lefloch, Bertrand; Favre, Cécile; Yamamoto, Satoshi

    2016-06-01

    We have analyzed rotational spectral line emission of OCS, CH3OH, HCOOCH3, and H2CS observed toward the low-mass Class 0 protostellar source IRAS 16293–2422 Source A at a sub-arcsecond resolution (∼0.″6 × 0.″5) with ALMA. Significant chemical differentiation is found on a scale of 50 au. The OCS line is found to trace well the infalling–rotating envelope in this source. On the other hand, the distributions of CH3OH and HCOOCH3 are found to be concentrated around the inner part of the infalling–rotating envelope. With a simple ballistic model of the infalling–rotating envelope, the radius of the centrifugal barrier (a half of the centrifugal radius) and the protostellar mass are evaluated from the OCS data to be from 40 to 60 au and from 0.5 to 1.0 M ⊙, respectively, assuming the inclination angle of the envelope/disk structure to be 60° (90° for the edge-on configuration). Although the protostellar mass is correlated with the inclination angle, the radius of the centrifugal barrier is not. This is the first indication of the centrifugal barrier of the infalling–rotating envelope in a hot corino source. CH3OH and HCOOCH3 may be liberated from ice mantles by weak accretion shocks around the centrifugal barrier and/or by protostellar heating. The H2CS emission seems to come from the disk component inside the centrifugal barrier in addition to the envelope component. The centrifugal barrier plays a central role not only in the formation of a rotationally supported disk but also in the chemical evolution from the envelope to the protoplanetary disk.

  6. 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.

  7. BROAD COMPONENTS IN OPTICAL EMISSION LINES FROM THE ULTRA-LUMINOUS X-RAY SOURCE NGC 5408 X-1

    SciTech Connect

    Cseh, D.; Corbel, S.

    2011-02-10

    High-resolution optical spectra of the ultra-luminous X-ray source (ULX) NGC 5408 X-1 show a broad component with a width of {approx}750 km s{sup -1} in the He II and H{beta} lines in addition to the narrow component observed in these lines and [O III]. Reanalysis of moderate-resolution spectra shows a similar broad component in the He II line. The broad component likely originates in the ULX system itself, probably in the accretion disk. The central wavelength of the broad He II line is shifted by 252 {+-} 47 km s{sup -1} between the two observations. If this shift represents motion of the compact object, then its mass is less than {approx}1800 M{sub sun}.

  8. MAGNETIC FIELDS AND INFALL MOTIONS IN NGC 1333 IRAS 4

    SciTech Connect

    Attard, Michael; Houde, Martin; Novak, Giles; Li Huabai; Vaillancourt, John E.; Dowell, C. Darren; Davidson, Jacqueline; Shinnaga, Hiroko

    2009-09-10

    We present single-dish 350 {mu}m dust continuum polarimetry as well as HCN and HCO{sup +} J = 4 {yields} 3 rotational emission spectra obtained on NGC 1333 IRAS 4. The polarimetry indicates a uniform field morphology over a 20'' radius from the peak continuum flux of IRAS 4A, in agreement with models of magnetically supported cloud collapse. The field morphology around IRAS 4B appears to be quite distinct, however, with indications of depolarization observed toward the peak flux of this source. Inverse P Cygni profiles are observed in the HCN J = 4 {yields} 3 line spectra toward IRAS 4A, providing a clear indication of infall gas motions. Taken together, the evidence gathered here appears to support the scenario that IRAS 4A is a cloud core in a critical state of support against gravitational collapse.

  9. Optical-faint, Far-infrared-bright Herschel Sources in the CANDELS Fields: Ultra-luminous Infrared Galaxies at z > 1 and the Effect of Source Blending

    NASA Astrophysics Data System (ADS)

    Yan, Haojing; Stefanon, Mauro; Ma, Zhiyuan; Willner, S. P.; Somerville, Rachel; Ashby, Matthew L. N.; Davé, Romeel; Pérez-González, Pablo G.; Cava, Antonio; Wiklind, Tommy; Kocevski, Dale; Rafelski, Marc; Kartaltepe, Jeyhan; Cooray, Asantha; Koekemoer, Anton M.; Grogin, Norman A.

    2014-07-01

    The Herschel very wide field surveys have charted hundreds of square degrees in multiple far-IR (FIR) bands. While the Sloan Digital Sky Survey (SDSS) is currently the best resource for optical counterpart identifications over such wide areas, it does not detect a large number of Herschel FIR sources and leaves their nature undetermined. As a test case, we studied seven "SDSS-invisible," very bright 250 μm sources (S 250 > 55 mJy) in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey fields where we have a rich multi-wavelength data set. We took a new approach to decompose the FIR sources, using the near-IR or the optical images directly for position priors. This is an improvement over the previous decomposition efforts where the priors are from mid-IR data that still suffer from the problem of source blending. We found that in most cases the single Herschel sources are made of multiple components that are not necessarily at the same redshifts. Our decomposition succeeded in identifying and extracting their major contributors. We show that these are all ultra-luminous infrared galaxies at z ~ 1-2 whose high L IR is mainly due to dust-obscured star formation. Most of them would not be selected as submillimeter galaxies. They all have complicated morphologies indicative of mergers or violent instability, and their stellar populations are heterogeneous in terms of stellar masses, ages, and formation histories. Their current ultra-luminous infrared galaxy phases are of various degrees of importance in their stellar mass assembly. Our practice provides a promising starting point for developing an automatic routine to reliably study bright Herschel sources.

  10. OPTICAL-FAINT, FAR-INFRARED-BRIGHT HERSCHEL SOURCES IN THE CANDELS FIELDS: ULTRA-LUMINOUS INFRARED GALAXIES AT z > 1 AND THE EFFECT OF SOURCE BLENDING

    SciTech Connect

    Yan, Haojing; Stefanon, Mauro; Ma, Zhiyuan; Willner, S. P.; Ashby, Matthew L. N.; Somerville, Rachel; Davé, Romeel; Pérez-González, Pablo G.; Cava, Antonio; Wiklind, Tommy; Kocevski, Dale; Rafelski, Marc; Kartaltepe, Jeyhan; Cooray, Asantha; Koekemoer, Anton M.; Grogin, Norman A.

    2014-07-01

    The Herschel very wide field surveys have charted hundreds of square degrees in multiple far-IR (FIR) bands. While the Sloan Digital Sky Survey (SDSS) is currently the best resource for optical counterpart identifications over such wide areas, it does not detect a large number of Herschel FIR sources and leaves their nature undetermined. As a test case, we studied seven ''SDSS-invisible'', very bright 250 μm sources (S {sub 250} > 55 mJy) in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey fields where we have a rich multi-wavelength data set. We took a new approach to decompose the FIR sources, using the near-IR or the optical images directly for position priors. This is an improvement over the previous decomposition efforts where the priors are from mid-IR data that still suffer from the problem of source blending. We found that in most cases the single Herschel sources are made of multiple components that are not necessarily at the same redshifts. Our decomposition succeeded in identifying and extracting their major contributors. We show that these are all ultra-luminous infrared galaxies at z ∼ 1-2 whose high L {sub IR} is mainly due to dust-obscured star formation. Most of them would not be selected as submillimeter galaxies. They all have complicated morphologies indicative of mergers or violent instability, and their stellar populations are heterogeneous in terms of stellar masses, ages, and formation histories. Their current ultra-luminous infrared galaxy phases are of various degrees of importance in their stellar mass assembly. Our practice provides a promising starting point for developing an automatic routine to reliably study bright Herschel sources.

  11. Better Ira Remsen Demonstration

    ERIC Educational Resources Information Center

    Dalby, David K.; Maynard, James H.; Moore, John W.

    2011-01-01

    Many versions of the classic Ira Remsen experience involving copper and concentrated nitric acid have been used as lecture demonstrations. Remsen's original reminiscence from 150 years ago is included in the Supporting Information, and his biography can be found on the Internet. This article presents a new version that makes the demonstration more…

  12. A LUMINOUS Be+WHITE DWARF SUPERSOFT SOURCE IN THE WING OF THE SMC: MAXI J0158-744

    SciTech Connect

    Li, K. L.; Kong, Albert K. H.; Lu, Ting-Ni; Charles, P. A.; Bartlett, E. S.; Coe, M. J.; McBride, V.; Rajoelimanana, A.; Udalski, A.; Masetti, N.; Franzen, Thomas

    2012-12-20

    We present a multi-wavelength analysis of the very fast X-ray transient MAXI J0158-744, which was detected by MAXI/GSC on 2011 November 11. The subsequent exponential decline of the X-ray flux was followed with Swift observations, all of which revealed spectra with low temperatures ({approx}100 eV), indicating that MAXI J0158-744 is a new Supersoft Source (SSS). The Swift X-ray spectra near maximum show features around 0.8 keV that we interpret as possible absorption from O VIII and emission from O, Fe, and Ne lines. We obtained SAAO and ESO optical spectra of the counterpart early in the outburst and several weeks later. The early spectrum is dominated by strong Balmer and He I emission, together with weaker He II emission. The later spectrum reveals absorption features that indicate a B1/2IIIe spectral type, and all spectral features are at velocities consistent with the Small Magellanic Cloud. At this distance, it is a luminous SSS (>10{sup 37} erg s{sup -1}) but whose brief peak luminosity of >10{sup 39} erg s{sup -1} in the 2-4 keV band makes it the brightest SSS yet seen at ''hard'' X-rays. We propose that MAXI J0158-744 is a Be-WD binary, and the first example to possibly enter ULX territory. The brief hard X-ray flash could possibly be a result of the interaction of the ejected nova shell with the B star wind in which the white dwarf (WD) is embedded. This makes MAXI J0158-744 only the third Be/WD system in the Magellanic Clouds, but it is by far the most luminous. The properties of MAXI J0158-744 give weight to previous suggestions that SSS in nearby galaxies are associated with early-type stellar systems.

  13. The Integrated X-Ray Spectrum of Galactic Populations of Luminous Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, R.; Becker, C. M.; Fabbiano, G.

    1996-01-01

    We compute the composite X-ray spectrum of a population of unresolved SSS's in a spiral galaxy such as our own or M31. The sources are meant to represent the total underlying population corresponding to all sources which have bolometric luminosities in the range of 10(exp 37) - 10(exp 38) ergs/s and kT on the order of tens of eV. These include close-binary supersoft sources, symbiotic novae, and planetary nebulae, for example. In order to determine whether the associated X-ray signal would be detectable, we also 'seed' the galaxy with other types of X-ray sources, specifically low-mass X-ray binaries (LMXB's) and high-mass X-ray binaries (HMXB's). We find that the total spectrum due to SSS's, LMXB's, and HMXB's exhibits a soft peak which owes its presence to the SSS population. Preliminary indications are that this soft peak may be observable.

  14. Is the Nova V2672 Oph a Luminous X-ray Source in Quiescence?

    NASA Astrophysics Data System (ADS)

    Mukai, Koji

    2014-09-01

    The very fast nova V2672 Oph had one of the shortest decay times (t2=2.3 d) and the broadest emission lines (FWZI up to 12,000 km/s) ever observed in novae. It may well be a recurrent nova with a near Chandrasekhar mass white dwarf. There is also a ROSAT all-sky survey Faint Source Catalog source consistent with its position: if confirmed, V2672 Oph would be only the third nova to have been detected in X-rays before the nova eruption. We therefore propose an ACIS-S imaging observation to provide the precise location, and rough timing and spectral characteristics of the ROSAT source. V2672 Oph may join V2487 Oph and V2491 Cyg as novae with quiescent X-ray luminosities not seen in normal cataclysmic variables.

  15. Optical Studies of Ultra Luminous X-ray Sources in NGC4490

    NASA Astrophysics Data System (ADS)

    Akyuz, Aysun; Avdan, Hasan; Avdan, Senay; Aksaker, Nazim

    2016-07-01

    We present optical studies of Ultraluminous X-ray sources (ULXs) in the spiral galaxy NGC4490 which is interacting with the irregular galaxy NGC 4485. ULXs are extra-nuclear, point-like X-ray sources with isotropic luminosities (Lx > 10 ^{39} erg s ^{-1}) above the Eddington limit for a 10 Msun black hole. HST/ACS/WFC and WFPC3 archival data have been analyzed to investigate the optical counterparts of five ULXs in NGC4490. Using relative astrometry the corrected ULX positions were derived only for three sources within the 1σ error radius of 0.5 arcsec on the HST images. We discuss the properties of three optical counterparts and constraints on their physical nature from multiband optical observations.

  16. MAXI J0158-744: A Luminous Supersoft Source in the Magellanic Bridge

    NASA Astrophysics Data System (ADS)

    McBride, V. A.; Li, K. L.; Kong, A. K. H.; Charles, P. A.; Lu, T.-N.; Bartlett, E. S.; Coe, M. J.; Rajoelimanana, A.; Udalski, A.; Masetti, N.; Franzen, T.

    2014-12-01

    We present a multi-wavelength analysis of the very fast supersoft source, MAXI J0158-744, which was subsequently identified with a Be star in the Magellanic Bridge. X-ray spectra are indicative of a nova, and we propose that the brief, hard X-ray flash is a result of the interaction of the ejected nova shell with the B star wind. MAXI J0158-744 is only the third Be+WD system known in the Magellanic Clouds. The properties of MAXI J0158-744 give weight to previous suggestions that supersoft sources in nearby galaxies are associated with early-type stellar companions.

  17. Dust near luminous ultraviolet stars

    NASA Technical Reports Server (NTRS)

    Henry, Richard C.

    1993-01-01

    This report describes research activities related to the Infrared Astronomical Satellite (IRAS) sky survey. About 745 luminous stars were examined for the presence of interstellar dust heated by a nearby star. The 'cirrus' discovered by IRAS is thermal radiation from interstellar dust at moderate and high galactic latitudes. The IRAS locates the dust which must (at some level) scatter ultraviolet starlight, although it was expected that thermal emission would be found around virtually every star, most stars shown no detectable emission. And the emission found is not uniform. It is not that the star is embedded in 'an interstellar medium', but rather what is found are discrete clouds that are heated by starlight. An exception is the dearth of clouds near the very hottest stars, implying that the very hottest stars play an active role with respect to destroying or substantially modifying the dust clouds over time. The other possibility is simply that the hottest stars are located in regions lacking in dust, which is counter-intuitive. A bibliography of related journal articles is attached.

  18. The Counterparts of the Luminous, Bursting X-ray Sources in Globular Clusters-LTSA98

    NASA Technical Reports Server (NTRS)

    Anderson, Scott F.

    2003-01-01

    Under the fifth year of the LTSA, we have extended our HST and Chandra work to a number of additional globular clusters. The remarkable sensitivity and positional accuracy of the Chandra observations are enabling us to maximally exploit HST for UV/optical identifications for X-ray binaries in the cores of multiple globular clusters. The dozens of lower-luminosity X-ray sources in each globular cluster deeply examined thus far have moved us firmly into the era of studies which encompass populations of close; the large range of cluster properties we are studying have, for the first tine, established a firm empirical confirmation of the (long-suspected theoretically) high importance that close binaries play in the dynamical stability and evolution of globular clusters. The LTSA support has been a cornerstone of our success over the past 5 years in studies of globular cluster X-ray sources and their counterparts.

  19. IRAS asteroid families

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.; Williams, J. G.; Tedesco, E. F.; Matson, D. L.

    1991-01-01

    The Infrared Astronomical Satellite (IRAS) sampled the entire asteroid population at wavelengths from 12 to 100 microns during its 1983 all sky survey. The IRAS Minor Planet Survey (IMPS) includes updated results for more recently numbered as well as other additional asteroids with reliable orbital elements. Albedos and diameters were derived from the observed thermal emission and assumed absolute visual magnitudes and then entered into the IMPS database at the Infrared Processing and Analysis Center (IPAC) for members of the Themis, Eos, Koronis and Maria asteroid families and compared with their visual colors. The IMPS results for the small (down to about 20 km) asteroids within these major families confirm trends previously noted for their larger members. Each of these dynamical families which are defined by their similar proper elements appears to have homogeneous physical properties.

  20. HECTOSPEC AND HYDRA SPECTRA OF INFRARED LUMINOUS SOURCES IN THE AKARI NORTH ECLIPTIC POLE SURVEY FIELD

    SciTech Connect

    Shim, Hyunjin; Im, Myungshin; Jeon, Yiseul; Kim, Seong Jin; Lee, Hyung Mok; Ko, Jongwan; Karouzos, Marios; Papovich, Casey; Willmer, Christopher; Weiner, Benjamin J.

    2013-08-15

    We present spectra of 1796 sources selected in the AKARI North Ecliptic Pole Wide Survey field, obtained with MMT/Hectospec and WIYN/Hydra, for which we measure 1645 redshifts. We complemented the generic flux-limited spectroscopic surveys at 11 {mu}m and 15 {mu}m, with additional sources selected based on the MIR and optical colors. In MMT/Hectospec observations, the redshift identification rates are {approx}80% for objects with R < 21.5 mag. On the other hand, in WIYN/Hydra observations, the redshift identification rates are {approx}80% at R magnitudes brighter than 19 mag. The observed spectra were classified through the visual inspection or from the line diagnostics. We identified 1128 star-forming or absorption-line-dominated galaxies, 198 Type-1 active galactic nuclei (AGNs), 8 Type-2 AGNs, 121 Galactic stars, and 190 spectra in unknown category due to low signal-to-noise ratio. The spectra were flux-calibrated but to an accuracy of 0.1-0.18 dex for most of the targets and worse for the remainder. We derive star formation rates (SFRs) from the mid-infrared fluxes or from the optical emission lines, showing that our sample spans an SFR range of 0.1 to a few hundred M{sub Sun} yr{sup -1}. We find that the extinction inferred from the difference between the IR and optical SFR increases as the IR luminosity increases but with a large scatter.

  1. M82 X-1 ---The Hyper Luminous X-Ray Source---

    NASA Astrophysics Data System (ADS)

    Tsuru, T. G.; Matsumoto, H.; Inui, T.; Matsushita, S.; Kawabe, R.; Harashima, T.; Maihara, T.; Iwamuro, F.

    By using ASCA and Chandra, we discovered a bright X-ray source M82 X-1 in the starburst galaxy M82. The peak luminosity of ˜ 1× 1041 ergs sec-1 and the location of off-center position of M82 in the starburst galaxy M82 suggest that M82 X-1 is a new type of black hole, intermediate massive black hole (IMBH). We also found an expanding molecular super bubble (EMSB) surrounding the IMBH. We propose a hypothesis that the IMBH was formed in the starburst activity 10^6˜ 10^7 yrs ago. We review the course of the discovery and show recent progress on studies of the X-ray spectrum and the position of M82 X-1.

  2. The IRAS2 and IRAS4 Outflows and Star Formation i NGC 1333

    NASA Technical Reports Server (NTRS)

    Langer, W. D.; Castets, A.; Lefloch, B.

    1996-01-01

    We report the first detection of the western bowshock component from IRAS2 in NGC 1333 along with observations of previously detected shocks and outflow winds from this source and those from IRAS4. We compare the shock and outflow distributions from these two young stellar objects, and the locations of other YSOs, with the overall distribution of the dense molecular gas in the star forming core using high spatial resolution observations of CS (J=2-->1, 3-->2, and 5-->4) emission made with the IRAM 30m antenna.

  3. Terminal speed of a gaseous stratus with finite optical depth over a luminous flat source

    NASA Astrophysics Data System (ADS)

    Masuda, Takao; Fukue, Jun

    2016-06-01

    We reexamine the terminal speed of a moving stratus irradiated by an infinite flat source, considering relativistic radiative transfer in the stratus. For the case of a particle, V. Icke (1989, A&A, 216, 294) analytically derived the terminal speed of (4-√{7})c/3 ˜ 0.45 c, whereas the terminal speed of a stratus with finite optical depth is calculated under the Eddington approximation (J. Fukue, 2014, PASJ, 66, 13), and becomes larger up to 0.7 c in the optically thin limit. In this paper, we numerically calculate radiative transfer in the stratus without the Eddington approximation, and obtain the terminal speed. In the optically thick limit the terminal speed approaches 0.47 c. In the optically thin limit, in contrast to the previous analytical study, it becomes small as the optical depth decreases, and approaches 0.26 c. This is due to the anisotropic effect of the radiation field in the optically thin regime.

  4. Terminal speed of a gaseous stratus with finite optical depth over a luminous flat source

    NASA Astrophysics Data System (ADS)

    Masuda, Takao; Fukue, Jun

    2016-04-01

    We reexamine the terminal speed of a moving stratus irradiated by an infinite flat source, considering relativistic radiative transfer in the stratus. For the case of a particle, V. Icke (1989, A&A, 216, 294) analytically derived the terminal speed of (4-√{7})c/3 ˜ 0.45 c, whereas the terminal speed of a stratus with finite optical depth is calculated under the Eddington approximation (J. Fukue, 2014, PASJ, 66, 13), and becomes larger up to 0.7 c in the optically thin limit. In this paper, we numerically calculate radiative transfer in the stratus without the Eddington approximation, and obtain the terminal speed. In the optically thick limit the terminal speed approaches 0.47 c. In the optically thin limit, in contrast to the previous analytical study, it becomes small as the optical depth decreases, and approaches 0.26 c. This is due to the anisotropic effect of the radiation field in the optically thin regime.

  5. Studies of IRAS sources at high galactic latitudes. I - Source counts at /b/greater than 60 deg and evidence for a north-south anisotropy of cosmological significance

    NASA Technical Reports Server (NTRS)

    Rowan-Robinson, M.; Walker, D.; Chester, T.; Soifer, T.; Fairclough, J.

    1986-01-01

    A study of the IRAS sky at b with an absolute value greater than 60 deg is conducted. Source counts at 12, 25, 60 and 100 microns are presented, and it is shown that emission from interstellar dust at 100 microns is localized to a few small areas of tathe galactic polar caps. At 12 and 25 microns, the sky is dominated by stars; at 60 and 100 microns, by galaxies. Comparison with the minisurvey source counts indicates the 12and 25-micron source denstiy is lower at the present latitude than at a latitude whereby the absolute value of b equals 10-40 deg. Due to the greatly reduced effects of emission from interstellar dust, the 100 micron survey reaches a factor 1.6 deeper in flux at the present latitude than the minisurvey. An anisotropy significant at the 4-sigma level was found between the north and south galactic polar caps at 60 and 100 microns, after exclusion of the Virgo cluster and of the few remaining areas significantly affected by interstellar-dust emission. It is suggested that this anisotropy represents a cosmologically significant anisotropy in the galaxy distribution. The scale of associated inhomogeneity is of the order of at least 100(50/H)Mpc.

  6. SPECTROSCOPY OF LUMINOUS z > 7 GALAXY CANDIDATES AND SOURCES OF CONTAMINATION IN z > 7 GALAXY SEARCHES

    SciTech Connect

    Capak, P.; Jullo, E.; Mobasher, B.; Scoville, N. Z.; Salvato, M.; McCracken, H.; Ilbert, O.; Menendez-Delmestre, K.; Aussel, H.; LeFloch, E.; Carilli, C.; Civano, F.; Elvis, M.; Giavalisco, M.; Kartaltepe, J.; Sanders, D. B.; Leauthaud, A.; Koekemoer, A. M.; Kneib, J.-P.; Schinnerer, E.

    2011-04-01

    We present three bright z{sup +}-dropout candidates selected from deep near-infrared (NIR) imaging of the COSMOS 2 deg{sup 2} field. All three objects match the 0.8-8 {mu}m colors of other published z > 7 candidates but are 3 mag brighter, facilitating further study. Deep spectroscopy of two of the candidates covering 0.64-1.02 {mu}m with Keck-DEIMOS and all three covering 0.94-1.10 {mu}m and 1.52-1.80 {mu}m with Keck-NIRSPEC detects weak spectral features tentatively identified as Ly{alpha} at z = 6.95 and z = 7.69 in two of the objects. The third object is placed at z {approx} 1.6 based on a 24 {mu}m and weak optical detection. A comparison with the spectral energy distributions of known z < 7 galaxies, including objects with strong spectral lines, large extinction, and large systematic uncertainties in the photometry, yields no objects with similar colors. However, the {lambda} > 1 {mu}m properties of all three objects can be matched to optically detected sources with photometric redshifts at z {approx} 1.8, so the non-detection in the i {sup +} and z {sup +} bands is the primary factor which favors a z > 7 solution. If any of these objects are at z {approx} 7, the bright end of the luminosity function is significantly higher at z > 7 than suggested by previous studies, but consistent within the statistical uncertainty and the dark matter halo distribution. If these objects are at low redshift, the Lyman break selection must be contaminated by a previously unknown population of low-redshift objects with very strong breaks in their broadband spectral energy distributions and blue NIR colors. The implications of this result on luminosity function evolution at high redshift are discussed. We show that the primary limitation of z > 7 galaxy searches with broad filters is the depth of the available optical data.

  7. A Stellar-mass Black Hole in the Ultra-luminous X-ray Source M82 X-1

    NASA Technical Reports Server (NTRS)

    Okajima, Takashi; Ebisawa, Ken; Kawaguchi, Toshihiro

    2007-01-01

    We have analyzed the archival XMM-Newton data of the archetypal Ultra-Luminous X-ray Source (ULX) M82 X-1 with an LO5 ksec exposure when the source was in the steady state. Thanks to the high photon statistics from the large effective area and long exposure, we were able to discriminate different X-ray continuum spectral models. Neither the standard accretion disk model (where the radial dependency of the disk effective temperature is T(r) proportional to r(sup -3/4)) nor a power-law model gives a satisfactory fit. In fact, observed curvature of the M82 X-1 spectrum was just between those of the two models. When the exponent of the radial dependence (p in T(r) proportional to r(sup -P)) of the disk temperature is allowed to be free, we obtained p = 0.61 (sup +0.03)(sub -0.02). Such a reduction of p from the standard value 3/4 under extremely high mass accretion rates is predicted from the accretion disk theory as a consequence of the radial energy advection. Thus, the accretion disk in M82 X-1 is considered to be in the Slim disk state, where an optically thick Advection Dominant Accretion Flow (ADAF) is taking place. We have applied a theoretical slim disk spectral model to M82 X-1, and estimated the black hole mass approximately equal to 19 - 32 solar mass. We conclude that M82 X-1 is a stellar black hole which has been produced through evolution of an extremely massive star, shining at a several times the super-Eddington luminosity.

  8. VizieR Online Data Catalog: IRAS PSC/FSC Combined Catalogue (Abrahamyan+ 2015)

    NASA Astrophysics Data System (ADS)

    Abrahamyan, H. V.; Mickaelian, A. M.; Knyazyan, A. V.

    2015-03-01

    Optical identifications of a few thousands of IRAS sources showed that IRAS Point Source and IRAS Faint Source catalogues (PSC and FSC, respectively) contain many quasars and active galactic nuclei, late-type stars, planetary nebulae, variables, etc. To increase the efficiency of using IRAS PSC and FSC, which contain a lot of common sources, one needs a joint catalogue of all IRAS point sources with improved data based on both catalogues. However, cross-correlation of the catalogues is not so easy, as the association of many sources is relative, and not always it is obvious, whose source from one catalogue corresponds to the other one in the second catalogue. This problem exists in case of using standard cross-correlation tools. Therefore, we have created a tool for cross-matching astronomical catalogues and we have applied it to IRAS PSC and FSC. Using this tool we have carried out identifications with a search radius corresponding to 3-σ of errors for each source individually rather than a standard radius for all sources. As a result, we obtained 73,770 associations. In addition, we have made cross-correlations with AKARI-IRC, AKARI-FIS and WISE catalogues. We created a catalogue of 345,163 IRAS sources with high positional accuracy and with 17 photometric measurements from 1.25 to 160 ?m range, providing a detailed catalogue for IRAS point sources. (1 data file).

  9. Spectroscopy of Luminous z > 7 Galaxy Candidates and Sources of Contamination in z > 7 Galaxy Searches

    NASA Astrophysics Data System (ADS)

    Capak, P.; Mobasher, B.; Scoville, N. Z.; McCracken, H.; Ilbert, O.; Salvato, M.; Menéndez-Delmestre, K.; Aussel, H.; Carilli, C.; Civano, F.; Elvis, M.; Giavalisco, M.; Jullo, E.; Kartaltepe, J.; Leauthaud, A.; Koekemoer, A. M.; Kneib, J.-P.; LeFloch, E.; Sanders, D. B.; Schinnerer, E.; Shioya, Y.; Shopbell, P.; Tanaguchi, Y.; Thompson, D.; Willott, C. J.

    2011-04-01

    We present three bright z +-dropout candidates selected from deep near-infrared (NIR) imaging of the COSMOS 2 deg2 field. All three objects match the 0.8-8 μm colors of other published z > 7 candidates but are 3 mag brighter, facilitating further study. Deep spectroscopy of two of the candidates covering 0.64-1.02 μm with Keck-DEIMOS and all three covering 0.94-1.10 μm and 1.52-1.80 μm with Keck-NIRSPEC detects weak spectral features tentatively identified as Lyα at z = 6.95 and z = 7.69 in two of the objects. The third object is placed at z ~ 1.6 based on a 24 μm and weak optical detection. A comparison with the spectral energy distributions of known z < 7 galaxies, including objects with strong spectral lines, large extinction, and large systematic uncertainties in the photometry, yields no objects with similar colors. However, the λ > 1 μm properties of all three objects can be matched to optically detected sources with photometric redshifts at z ~ 1.8, so the non-detection in the i + and z + bands is the primary factor which favors a z > 7 solution. If any of these objects are at z ~ 7, the bright end of the luminosity function is significantly higher at z > 7 than suggested by previous studies, but consistent within the statistical uncertainty and the dark matter halo distribution. If these objects are at low redshift, the Lyman break selection must be contaminated by a previously unknown population of low-redshift objects with very strong breaks in their broadband spectral energy distributions and blue NIR colors. The implications of this result on luminosity function evolution at high redshift are discussed. We show that the primary limitation of z > 7 galaxy searches with broad filters is the depth of the available optical data. Based on observations with the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space

  10. High-resolution imaging of the molecular outflows in two mergers: IRAS 17208-0014 and NGC 1614

    NASA Astrophysics Data System (ADS)

    García-Burillo, S.; Combes, F.; Usero, A.; Aalto, S.; Colina, L.; Alonso-Herrero, A.; Hunt, L. K.; Arribas, S.; Costagliola, F.; Labiano, A.; Neri, R.; Pereira-Santaella, M.; Tacconi, L. J.; van der Werf, P. P.

    2015-08-01

    Context. Galaxy evolution scenarios predict that the feedback of star formation and nuclear activity (AGN) can drive the transformation of gas-rich spiral mergers into (ultra) luminous infrared galaxies and, eventually, lead to the build-up of QSO/elliptical hosts. Aims: We study the role that star formation and AGN feedback have in launching and maintaining the molecular outflows in two starburst-dominated advanced mergers, NGC 1614 (DL = 66 Mpc) and IRAS 17208-0014 (DL = 181 Mpc), by analyzing the distribution and kinematics of their molecular gas reservoirs. Both galaxies present evidence of outflows in other phases of their ISM. Methods: We used the Plateau de Bure interferometer (PdBI) to image the CO(1-0) and CO(2-1) line emissions in NGC 1614 and IRAS 17208-0014, respectively, with high spatial resolution (0''&dotbelow;5-1''&dotbelow;2). The velocity fields of the gas were analyzed and modeled to find the evidence of molecular outflows in these sources and characterize the mass, momentum, and energy of these components. Results: While most (≥95%) of the CO emission stems from spatially resolved (~2-3 kpc-diameter) rotating disks, we also detect in both mergers the emission from high-velocity line wings that extend up to ±500-700 km s-1, well beyond the estimated virial range associated with rotation and turbulence. The kinematic major axis of the line-wing emission is tilted by ~90° in NGC 1614 and by ~180° in IRAS 17208-0014 relative to the major axes of their respective rotating disks. These results can be explained by the existence of non-coplanar molecular outflows in both systems: the outflow axis is nearly perpendicular to the rotating disk in NGC 1614, but it is tilted relative to the angular momentum axis of the rotating disk in IRAS 17208-0014. Conclusions: In stark contrast to NGC 1614, where star formation alone can drive its molecular outflow, the mass, energy, and momentum budget requirements of the molecular outflow in IRAS 17208-0014 can

  11. IRAS observations of NGC 1052

    NASA Technical Reports Server (NTRS)

    Neugebauer, G.; Soifer, B. T.; Rice, W.; Rowan-Robinson, M.

    1984-01-01

    The galaxy NGC 1052 has been observed with the IRAS satellite. The infrared emission at 100 microns is substantially larger than a smooth extrapolation of the radio data. Because of the large diaphragm size of IRAS, it is impossible to decide uniquely if the infrared radiation represents a self-absorbed nonthermal spectrum or thermal reradiation by heated dust.

  12. IRAS observations of NGC 1052

    SciTech Connect

    Neugebauer, G.; Soifer, B.T.; Rice, W.

    1984-12-01

    The galaxy NGC 1052 has been observed with the IRAS satellite. The infrared emission at 100 microns is substantially larger than a smooth extrapolation of the radio data. Because of the large diaphragm size of IRAS, it is impossible to decide uniquely if the infrared radiation represents a self-absorbed nonthermal spectrum or thermal reradiation by heated dust. 23 references.

  13. Testing the Paradigm that Ultra-Luminous X-Ray Sources as a Class Represent Accreting Intermediate

    NASA Technical Reports Server (NTRS)

    Berghea, C. T.; Weaver, K. A.; Colbert, E. J. M.; Roberts, T. P.

    2008-01-01

    To test the idea that ultraluminous X-ray sources (ULXs) in external galaxies represent a class of accreting Intermediate-Mass Black Holes (IMBHs), we have undertaken a program to identify ULXs and a lower luminosity X-ray comparison sample with the highest quality data in the Chandra archive. We establish a general property of ULXs that the most X-ray luminous objects possess the fattest X-ray spectra (in the Chandra band pass). No prior sample studies have established the general hardening of ULX spectra with luminosity. This hardening occurs at the highest luminosities (absorbed luminosity > or equals 5x10(exp 39) ergs/s) and is in line with recent models arguing that ULXs are actually stellar-mass black holes. From spectral modeling, we show that the evidence originally taken to mean that ULXs are IMBHs - i.e., the "simple IMBH model" - is nowhere near as compelling when a large sample of ULXs is looked at properly. During the last couple of years, XMM-Newton spectroscopy of ULXs has to some large extent begun to negate the simple IMBH model based on fewer objects. We confirm and expand these results, which validates the XMM-Newton work in a broader sense with independent X-ray data. We find (1) that cool disk components are present with roughly equal probability and total flux fraction for any given ULX, regardless of luminosity, and (2) that cool disk components extend below the standard ULX luminosity cutoff of 10(exp 39) ergs/s, down to our sample limit of 10(exp 38:3) ergs/s. The fact that cool disk components are not correlated with luminosity damages the argument that cool disks indicate IMBHs in ULXs, for which a strong statistical support was never made.

  14. An active M star with X-ray double flares disguised as an ultra-luminous X-ray source

    NASA Astrophysics Data System (ADS)

    Guo, Jin-Cheng; Liu, Ji-Feng; Wang, Song; Wu, Yue; Qin, Yu-Xiang

    2016-02-01

    Here we present research on an ultra-luminous X-ray source (ULX) candidate 2XMM J140229.91+542118.8. The X-ray light curves of this ULX candidate in M101 exhibit features of a flare star. More importantly, the Chandra light curve displays unusual X-ray double flares, which is comprised of two close peaks. The X-ray (0.3-11.0 keV) flux of the first peak was derived from the two-temperature APEC model as ˜ 1.1 ± 0.1 × 10-12 erg cm-2 s-1. The observed flux at its first peak increased by about two orders of magnitude in X-ray as compared to quiescence. The slope of the second fast decay phase is steeper than the slope of the first fast decay phase, indicating that the appearance of a second flare accelerated the cooling of the first flare in a way we do not understand yet. We also observed its optical counterpart using a 2.16 m telescope administered by National Astronomical Observatories, Chinese Academy of Sciences. By optical spectral fitting, it is confirmed to be a late type dMe2.5 star. According to the spectral type and apparent magnitude of its optical counterpart, we estimate the photometric distance to be ˜ 133.4 ± 14.2 pc. According to the X-ray spectral fitting, a possible explanation is provided. However, more similar close double flares are needed to confirm whether this accelerated cooling event is a unique coincidence or a common physical process during double flaring.

  15. The scaling of X-ray variability with luminosity in ultra-luminous X-ray sources

    NASA Astrophysics Data System (ADS)

    González-Martín, O.; Papadakis, I.; Reig, P.; Zezas, A.

    2011-02-01

    Aims: We investigate the relationship between the X-ray variability amplitude and X-ray luminosity for a sample of 14 bright ultra-luminous X-ray sources (ULXs) with XMM-Newton/EPIC data, and compare it with the well-established, similar relationship for active galactic nuclei (AGN). Methods: We computed the normalised excess variance in the 2-10 keV light curves of these objects and their 2-10 keV band intrinsic luminosity L2-10 keV. We also determined model "variability-luminosity" relationships for AGN, under several assumptions regarding their power-spectral shape. We compared these model predictions at low luminosities with the ULX data. Results: The variability amplitude of the ULXs is significantly smaller than expected from a simple extrapolation of the AGN "variability-luminosity" relationship at low luminosities. We also find evidence of an anti-correlation between the variability amplitude and L2-10 keV for ULXs. The shape of this relationship is consistent with the AGN data but only if the ULXs data are shifted by four orders of magnitudes in luminosity. Conclusions: Most (but not all) of the ULXs could be "scaled-down" version of AGN if we assume that i) their black hole mass and accretion rate are between ~(2.5-30)× 103 M⊙ and ~1-80% of the Eddington limit and ii) their power spectral density has a doubly broken power-law shape. This shape and accretion rate is consistent with Galactic black hole systems operating in their so-called "low-hard" and "very-high" states.

  16. Early science with the Large Millimeter Telescope: observations of extremely luminous high-z sources identified by Planck

    NASA Astrophysics Data System (ADS)

    Harrington, K. C.; Yun, Min S.; Cybulski, R.; Wilson, G. W.; Aretxaga, I.; Chavez, M.; De la Luz, V.; Erickson, N.; Ferrusca, D.; Gallup, A. D.; Hughes, D. H.; Montaña, A.; Narayanan, G.; Sánchez-Argüelles, D.; Schloerb, F. P.; Souccar, K.; Terlevich, E.; Terlevich, R.; Zeballos, M.; Zavala, J. A.

    2016-06-01

    We present 8.5 arcsec resolution 1.1-mm continuum imaging and CO spectroscopic redshift measurements of eight extremely bright submillimetre galaxies identified from the Planck and Herschel surveys, taken with the Large Millimeter Telescope's AzTEC and Redshift Search Receiver instruments. We compiled a candidate list of high-redshift galaxies by cross-correlating the Planck Surveyor mission's highest frequency channel (857 GHz, full width at half-maximum = 4.5 arcmin) with the archival Herschel Spectral and Photometric Imaging Receiver imaging data, and requiring the presence of a unique, single Herschel counterpart within the 150-arcsec search radius of the Planck source positions with 350-μm flux density larger than 100 mJy, excluding known blazars and foreground galaxies. All eight candidate objects observed are detected in 1.1 mm continuum by AzTEC bolometer camera, and at least one CO line is detected in all cases with a spectroscopic redshift between 1.3 < zCO < 3.3. Their infrared (IR) spectral energy distributions (SEDs) mapped using the Herschel and AzTEC photometry are consistent with cold dust emission with characteristic temperature between Td = 43 and 84 K. With apparent IR luminosity of up to LIR = 3 × 1014μ-1 L⊙, they are some of the most luminous galaxies ever found (with yet unknown gravitational magnification factor μ). The analysis of their SEDs suggests that star formation is powering the bulk of their extremely large IR luminosities. Derived molecular gas masses of M_{H_2}=(0.6-7.8)× 10^{11} M_{odot } (for μ ≈ 10) also make them some of the most gas-rich high-redshift galaxies ever detected.

  17. X-ray QPOs from the Ultra-luminous X-ray Source in M82: Evidence Against Beaming

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod E.; Mushotzky, Richard F.

    2003-01-01

    We report the discovery with the European Photon Imaging Camera (EPIC) CCD cameras onboard XMM-Newton of a 54 mHz quasiperiodic oscillation (QPO) in the greater than 2 keV X-ray flux from the ultra-luminous X-ray source (ULX) X41.4+60 in the starburst galaxy M82. This is the first detection of a QPO in the X-ray flux from an extra-Galactic ULX, and confirms that the source is a compact object. The QPO is detected in the combined PN and MOS data at the approx. 6sigma level, and separately at lower significances in both the PN and MOS instruments. It had a centroid frequency of 54.3 +/- 0.9 mHz, a coherence Q is identical with nu(sub 0)/Delta nu(sub fwhm) is approx. 5, and an amplitude (rms) in the 2 - 10 keV band of 8.5%. Below about 0.2 Hz the power spectrum can be described by a power-law with index approx. 1, and integrated amplitude (rms) of 13.5%. The X-ray spectrum requires a curving continuum, with a disk-blackbody (diskbb) at T = 3.1 keV providing an acceptable, but not unique, fit. A broad Fe line centered at 6.55 keV is required in all fits, but the equivalent width (EW) of the line is sensitive to the choice of continuum model. There is no evidence of a reflection component. The implied bolometric luminosity is approx. 4 - 5 x 10(exp 40) ergs/s. Data from several archival Rossi X-ray Timing Explorer (RXTE) pointings at M82 also show evidence for QPOs in the 50 - 100 mHz frequency range. Several Galactic black hole candidates (BHCs), including GRS 1915+105, GRO J1655-40, and XTE 1550-564, show QPOs in the same frequency range as the 50 - 100 mHz QPOs in X41.4+60, which at first glance suggests a possible connection with such objects. However, strong, narrow QPOs provide solid evidence for disk emission, and thus present enormous theoretical difficulties for models which rely on either geometrically or relativistically beamed emission to account for the high X-ray luminosities. We discuss the implications of our findings for models of the ULX sources.

  18. The nature of IRAS 19312+1950 revealed using Herschel: A massive YSO with peculiar maser properties

    NASA Astrophysics Data System (ADS)

    Cordiner, Martin; Charnley, Steven B.; Boogert, Adwin; Justtanont, Kay; Cox, Nick; Smith, Robert G.; Tielens, Xander; Wirström, Eva S.

    2016-06-01

    IRAS 19312+1950 is a bright, compact infrared source that has eluded firm characterization since its discovery. The SiO and OH maser properties are indicative of a high mass-loss evolved star, yet the complex chemistry and rising far-infrared SED are more characteristic of the envelope of a young stellar object (YSO). In order to elucidate the physical properties of IRAS 19312+1950, we obtained Herschel PACS and HIFI observations of gas and dust in the range 54-550 micron. Numerous detections of CO and H2O rotational lines were obtained, spanning a broad range of upper-state energy levels and probing different excitation regimes of the source. The PACS maps exhibit a compact, slightly asymmetric continuum source, indicative of a large mass of cool dust, whereas the far-IR CO spectrum reveals the presence of an excited gas component at around 200 K. Our HIFI observations show a complex kinematic structure indicative of a cool circumstellar envelope and fast outflow with a velocity up to 90 km/s along the line of sight. From Spitzer spectroscopy, we identify the presence of ice absorption bands due to H2O at 5.8 micron and CO2 at 15 micron, characteristic of interstellar/protostellar material. Combining the Herschel and Spitzer data with previous continuum measurements, the SED is found to be consistent with a massive, luminous central source surrounded by a dense, warm disk and a dusty envelope with large bipolar outflow cavities. The distinctive infrared SED and far-IR spectral features with broad, Gaussian-like outflow wings strongly suggest that IRAS 19312+1950 should be classified as a rare example of an isolated, accreting high-mass YSO with unusual maser properties, rather than an evolved star. In this presentation, the implications of the unique properties of this source will be discussed, along with our proposed ALMA observations required to confirm the classification of this object.

  19. V1647 Orionis = IRAS 05436-0007

    NASA Astrophysics Data System (ADS)

    Vig, S.; Ghosh, S. K.; Ojha, D. K.; Kulkarni, V. K.

    2004-06-01

    S. Vig, S. K. Ghosh, and D. K. Ojha, Tata Institute of Fundamental Research, Mumbai, in collaboration with V. K. Kulkarni (National Centre of Radio Astrophysics, Pune), report that a radio- continuum observation of IRAS 05436-0007, obtained at 1272 MHz using the Giant Metrewave Radio Telescope on Feb. 14.5 UT, shows no radio emission within a 1'.5 x 1'.5 region around IRAS 05436-0007 (R.A. = 5h46m13s.1, Decl. = -0o06'05", equinox 2000.0; from 2MASS), with a 5-sigma upper limit of 0.15 mJy/beam (synthesized beam size 5".61 x 2".72, p.a. -48.91 deg). All of the sources from the NRAO/VLA Sky Survey Catalog within this region (covering a 25'- diameter circular area centered on the nebula) were detected.

  20. Accretion Disk Spectra of the Ultra-luminous X-ray Sources in Nearby Spiral Galaxies and Galactic Superluminal Jet Sources

    NASA Technical Reports Server (NTRS)

    White, Nicholas E. (Technical Monitor); Ebisawa, Ken; Zycki, Piotr; Kubota, Aya; Mizuno, Tsunefumi; Watarai, Ken-ya

    2003-01-01

    Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and Galactic superluminal jet sources share the common spectral characteristic that they have unusually high disk temperatures which cannot be explained in the framework of the standard optically thick accretion disk in the Schwarzschild metric. On the other hand, the standard accretion disk around the Kerr black hole might explain the observed high disk temperature, as the inner radius of the Kerr disk gets smaller and the disk temperature can be consequently higher. However, we point out that the observable Kerr disk spectra becomes significantly harder than Schwarzschild disk spectra only when the disk is highly inclined. This is because the emission from the innermost part of the accretion disk is Doppler-boosted for an edge-on Kerr disk, while hardly seen for a face-on disk. The Galactic superluminal jet sources are known to be highly inclined systems, thus their energy spectra may be explained with the standard Kerr disk with known black hole masses. For ULXs, on the other hand, the standard Kerr disk model seems implausible, since it is highly unlikely that their accretion disks are preferentially inclined, and, if edge-on Kerr disk model is applied, the black hole mass becomes unreasonably large (greater than or approximately equal to 300 Solar Mass). Instead, the slim disk (advection dominated optically thick disk) model is likely to explain the observed super- Eddington luminosities, hard energy spectra, and spectral variations of ULXs. We suggest that ULXs are accreting black holes with a few tens of solar mass, which is not unexpected from the standard stellar evolution scenario, and their X-ray emission is from the slim disk shining at super-Eddington luminosities.

  1. Luminous presence

    NASA Astrophysics Data System (ADS)

    Dawson, Paula

    2008-02-01

    The Luminous Presence project examines the use of standard film language in the framing, angle and of points of view of holographic subjects though eight digital holographic stereograms; seven 25 x 25 cm, Hail, Water, Rain, Snow, Sun, Text, Imprint and 1.5 x 1 m, Luminous Presences i. However, before embarking on a discussion of how filmic language can be used in digital holograms it is first important to explain why this line of investigation could be fruitful. Undoubtedly several of the compositional practices which sprung up and evolved throughout the development of the diverse forms of the holographic medium have contributed to a unique hologram pictorial language, however it is well known that the reading of visual imagery of any type relies a great deal on the viewer's knowledge of and experience of other images .The lens-recorded imagery of film is a far more familiar language than that of holograms and the correlation between certain filmic pictorial conventions and emotional responses are well documented and understood. ii . In short the language of film contains a highly nuanced vocabulary of shot types and lens types (which may be criticised as being formulaic) yet are effective in lending emotion to figures.

  2. Infrared Study of the Southern Galactic Star-Forming Regions Associated with IRAS 10049-5657 and IRAS 10031-5632

    NASA Astrophysics Data System (ADS)

    Vig, S.; Ghosh, S. K.; Ojha, D. K.; Verma, R. P.

    2008-10-01

    We investigate the physical conditions of the interstellar medium and stellar components in the regions of the southern Galactic star-forming complexes associated with IRAS 10049-5657 and IRAS 10031-5632. These regions have been mapped simultaneously in two far-infrared bands (λeff ~ 150 and 210 μm), with ~1' angular resolution using the Tata Institute of Fundamental Research 1 m balloon-borne telescope. Spatial distribution of the temperature of cool dust and optical depth at 200 μm have been obtained taking advantage of the similar beams in the two bands. The HIRES processed Infrared Astronomical Satellite (IRAS) maps at 12, 25, 60, and 100 μm have been used for comparison. Using the Two Micron All Sky Survey near-infrared sources, we find the stellar populations of the embedded young clusters. A rich cluster of OB stars is seen in the IRAS 10049-5657 region. The fits to the stellar density radial profile of the cluster associated with IRAS 10049-5657 have been explored with the inverse radius profile as well as the King's profile; the cluster radius is ~2 pc. The source in the cluster closest to the IRAS peak is IRA-7, which lies above the zero-age main-sequence curve of spectral type O5 in the color-magnitude diagram. Unlike IRAS 10049-5657, a small cluster comprising a few deeply embedded sources is seen at the location of IRAS 10031-5632. Self-consistent radiative transfer modeling aimed at extracting important physical and geometrical details of the two IRAS sources shows that the best-fit models are in good agreement with the observed spectral energy distributions. The geometric details of the associated cloud and optical depths (τ100) have been estimated. A uniform density distribution of dust and gas is implied for both the sources. In addition, the infrared ionic fine-structure line emission from gas has been modeled for both the regions and compared with data from the IRAS low-resolution spectrometer. For IRAS 10049-5657, the observed and modeled

  3. Ultra-luminous X-Ray Sources in HARO II and the Role of X-Ray Binaries in Feedback in Lyα Emitting Galaxies

    NASA Astrophysics Data System (ADS)

    Prestwich, A. H.; Jackson, F.; Kaaret, P.; Brorby, M.; Roberts, T. P.; Saar, S. H.; Yukita, M.

    2015-10-01

    Lyman Break Analogs (LBAs) are local proxies of high-redshift Lyman Break Galaxies. Spatially resolved studies of nearby starbursts have shown that Lyman continuum and line emission are absorbed by dust and that the Lyα is resonantly scattered by neutral hydrogen. In order to observe Lyα emission from star-forming regions, some source of feedback is required to blow the neutral gas away from the starburst to prevent scattering and allow the Lyα emission to escape. We show that there are two X-ray point sources embedded in the diffuse emission of the LBA galaxy Haro 11. CXOU J003652.4-333316 (abbreviated to Haro 11 X-1) is an extremely luminous (L{}{{X}}˜ {10}41 erg s-1), spatially compact source with a hard-X-ray spectrum. We suggest that the X-ray emission from Haro 11 X-1 is dominated by a single accretion source. This might be an active galactic nucleus or a source similar to the extreme black hole binary (BHB) M82 X-1. The hard X-ray spectrum indicates that Haro 11 X-1 may be a BHB in a low accretion state. In this case, the very high X-ray luminosity suggests an intermediate mass black hole that could be the seed for formation of a supermassive black hole. Source CXOU J003652.7-33331619.5 (abbreviated Haro 11 X-2) has an X-ray luminosity of {L}{{X}}˜ 5× {10}40 erg s-1 and a soft X-ray spectrum (power-law photon index Γ ˜ 2.2). This strongly suggests that Haro 11 X-2 is an X-ray binary in the ultra luminous state (i.e., an Ultra Luminous X-ray source, ULX). Haro 11 X-2 is coincident with the star-forming knot that is the source of the Lyα emission. The association of a ULX with Lyα emission raises the possibility that strong winds from X-ray binaries play an important role in injecting mechanical power into the interstellar medium, thus blowing away neutral material from the starburst region and allowing the Lyα to escape. We suggest that feedback from X-ray binaries may play a significant role in allowing Lyα emission to escape from galaxies in the

  4. IRAS observations of matter around nearby stars

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.

    1985-01-01

    A systematic search of the IRAS point-source catalog has led to the identification of eight new nearby stars that are Vega-like in terms of their large 60-micron excess. These stars are distinguished by the predominance of spectral type A and the absence of double stars in the Vega-like group. Both effects are intuitively consistent with the interpretation that the 60-micron excess radiation is due to a disk of protoplanetary material, suggesting an early phase in the evolution of a planetary system; however, this distribution can also be due to luminosity and brightness selection effects.

  5. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 7: The small scale structure catalog

    NASA Technical Reports Server (NTRS)

    Helou, George (Editor); Walker, D. W. (Editor)

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched January 26, 1983. During its 300-day mission, it surveyed over 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. Volume 1 describes the instrument, the mission, and the data reduction process. Volumes 2 through 6 present the observations of the approximately 245,000 individual point sources detected by IRAS; each volume gives sources within a specified range of declination. Volume 7 gives the observations of the approximately 16,000 sources spatially resolved by IRAS and smaller than 8'. This is Volume 7, The Small Scale Structure Catalog.

  6. A very deep IRAS survey. III - VLA observations

    NASA Astrophysics Data System (ADS)

    Hacking, Perry; Beichman, C. A.; Condon, J. J.; Houck, J. R.

    1989-04-01

    The 60-micron fluxes and positions of sources (primarily starburst galaxies) found in a deep IRAS survey by Hacking and Houck (1987) are compared with 1.49 HGz maps made by the Very Large Array. The radio results are consistent with radio measurements of brighter IRAS galaxies and provide evidence that infrared cirrus does not contaminate the 60-micron sample. The flux-independent ratio of infrared to radio flux densities implies that the 1.4 GHz luminosity function for spiral galaxies is evolving at less than (1 + z) to the power of 4 relative to the 60-micron luminosity function.

  7. 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.

  8. On the Nature of the Enigmatic Object IRAS 19312+1950: A Rare Phase of Massive Star Formation?

    NASA Astrophysics Data System (ADS)

    Cordiner, M. A.; Boogert, A. C. A.; Charnley, S. B.; Justtanont, K.; Cox, N. L. J.; Smith, R. G.; Tielens, A. G. G. M.; Wirström, E. S.; Milam, S. N.; Keane, J. V.

    2016-09-01

    IRAS 19312+1950 is a peculiar object that has eluded firm characterization since its discovery, with combined maser properties similar to an evolved star and a young stellar object (YSO). To help determine its true nature, we obtained infrared spectra of IRAS 19312+1950 in the range 5–550 μm using the Herschel and Spitzer space observatories. The Herschel PACS maps exhibit a compact, slightly asymmetric continuum source at 170 μm, indicative of a large, dusty circumstellar envelope. The far-IR CO emission line spectrum reveals two gas temperature components: ≈0.22 M ⊙ of material at 280 ± 18 K, and ≈1.6 M ⊙ of material at 157 ± 3 K. The O i 63 μm line is detected on-source but no significant emission from atomic ions was found. The HIFI observations display shocked, high-velocity gas with outflow speeds up to 90 km s‑1 along the line of sight. From Spitzer spectroscopy, we identify ice absorption bands due to H2O at 5.8 μm and CO2 at 15 μm. The spectral energy distribution is consistent with a massive, luminous (∼2 × 104 L ⊙) central source surrounded by a dense, warm circumstellar disk and envelope of total mass ∼500–700 M ⊙, with large bipolar outflow cavities. The combination of distinctive far-IR spectral features suggest that IRAS 19312+1950 should be classified as an accreting, high-mass YSO rather than an evolved star. In light of this reclassification, IRAS 19312+1950 becomes only the fifth high-mass protostar known to exhibit SiO maser activity, and demonstrates that 18 cm OH maser line ratios may not be reliable observational discriminators between evolved stars and YSOs. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  9. High-resolution IRAS observations of the Rho Ophiuchi cloud core

    SciTech Connect

    Young, E.T.; Lada, C.J.; Wilking, B.A.

    1986-05-01

    IRAS high-resolution (12, 25, 60, and 100 microns) observations of the Rho Ophiuchi cloud core are presented. Analysis of the 12 micron data reveals 18 individual embedded sources with a surface brightness of greater than 1 Jy/sq arcmin and far-infrared luminosities ranging between 0.2-21 solar luminosities. Infrared observations collected at the Infrared Telescope Facility in Mauna Kea, Hawaii in July 1984 and April 1985 are utilized to identify 13 near-infrared objects in the IRAS data. The ground-based fluxes are compared to IRAS density fluxes; it is observed that the ground-based fluxes are lower by about a factor of three than the IRAS fluxes, indicating the presence of midinfrared emission due to hot dust on angular scales greater than 6-13 arcsec. It is noted that the IRAS observations provide a more complete description of the embedded population in the Rho Ophiuchi core than previous studies. 10 references.

  10. Infrared Astronomical Satellite (IRAS) image reconstruction and restoration

    NASA Technical Reports Server (NTRS)

    Gonsalves, R. A.; Lyons, T. D.; Price, S. D.; Levan, P. D.; Aumann, H. H.

    1987-01-01

    IRAS sky mapping data is being reconstructed as images, and an entropy-based restoration algorithm is being applied in an attempt to improve spatial resolution in extended sources. Reconstruction requires interpolation of non-uniformly sampled data. Restoration is accomplished with an iterative algorithm which begins with an inverse filter solution and iterates on it with a weighted entropy-based spectral subtraction.

  11. A very deep IRAS survey at the north ecliptic pole

    NASA Technical Reports Server (NTRS)

    Houck, J. R.; Hacking, P. B.; Condon, J. J.

    1987-01-01

    The data from approximately 20 hours observation of the 4- to 6-square degree field surrounding the north ecliptic pole have been combined to produce a very deep IR survey at the four IRAS bands. Scans from both pointed and survey observations were included in the data analysis. At 12 and 25 microns the deep survey is limited by detector noise and is approximately 50 times deeper than the IRAS Point Source Catalog (PSC). At 60 microns the problems of source confusion and Galactic cirrus combine to limit the deep survey to approximately 12 times deeper than the PSC. These problems are so severe at 100 microns that flux values are only given for locations corresponding to sources selected at 60 microns. In all, 47 sources were detected at 12 microns, 37 at 25 microns, and 99 at 60 microns. The data-analysis procedures and the significance of the 12- and 60-micron source-count results are discussed.

  12. A catalog of co-added IRAS fluxes of Orion population stars

    NASA Technical Reports Server (NTRS)

    Weaver, Wm. B.; Jones, Gordon

    1992-01-01

    A catalog of co-added IRAS fluxes for the pre-main-sequence objects in the Herbig-Bell catalog (HBC) is presented. This catalog doubles the number of HBC stars with detected IRAS fluxes and provides improved flux values for the previously known sources. Noise level are given for all HBC fields in each band, permitting upper limits to be estimated for all undetected sources.

  13. Water masers in Compton-thick AGN. I. Detailed study of the new water megamaser in IRAS 15480-0344

    NASA Astrophysics Data System (ADS)

    Castangia, P.; Tarchi, A.; Caccianiga, A.; Severgnini, P.; Della Ceca, R.

    2016-02-01

    Context. A relationship between the water maser detection rate and large nuclear column densities in AGN has often been cited in the literature. Indeed, detailed studies of luminous water masers, typically associated with the nuclear activity, allow us to investigate the innermost regions of AGN, with an impact on the still debated Unified Model for this class of objects. Aims: We have recently entertained a search for maser emission in a well-defined sample of Compton-thick AGN aimed at investigating, on firm statistical bases, the aforementioned relationship. While the survey is still ongoing, and is the subject of a forthcoming publication, a new luminous water maser has been detected in the lenticular (field) S0 galaxy IRAS 15480-0344, whose origin, associated with an accretion disc or a nuclear outflow/jet, needs to be assessed. Methods: Multi-epoch single-dish observations and VLBI measurements were performed to investigate the distribution, spatial extension, and variability of the maser emission in order to infer the main characteristics of the water megamaser. Results: The new detection in IRAS 15480-0344 is reported: a megamaser with a total single-dish isotropic luminosity of ~200 L⊙ and a profile composed of two main features, a broad line with a full width to half maximum (FWHM) linewidth of ~90 km s-1 and a narrow (FWHM< 1 km s-1) one. We performed a follow-up to the detection with the Very Long Baseline Array (VLBA) and confidently detected only the narrow component, which is coincident with the nuclear radio continuum emission detected with the Very Large Array at 8.4 GHz. A weak narrow feature has also been detected in the velocity range of the broad feature and is located 15 pc to the north-west with respect to the stronger component. Neither maser spot is associated with the compact radio continuum sources derived from the same VLBA dataset. Conclusions: The different line profiles and the spatial separation between the two features in the

  14. Water Masers Associated with IRAS 4A

    NASA Astrophysics Data System (ADS)

    Marvel, K. B.; Claussen, M.; Wootten, A.; Wilking, B.

    2000-05-01

    Observations of water masers near Young Stellar Objects (YSOs) are capable of revealing gas kinematics within a few AU of stars undergoing formation. Low mass YSOs are especially interesting as they are analogues of our own Sun. Several sources have been mapped in recent years and have shown proper motions indicative of bipolar outflowing material. Velocities are typically about 75 km/s and are clearly bipolar. Occasionally, bowshock structures have been observed (Imai et al. 1999, Claussen et al. 1999), showing the interaction between the jet and the ambient medium and perhaps indicating that the bipolar outflow occurs episodically. I present images and proper motions for the water masers associated with IRAS 4A. They are consistent with other sources of this class.

  15. A Chandra X-Ray Study of NGC 1068 IL the Luminous X-Ray Source Population

    NASA Technical Reports Server (NTRS)

    Smith, David A.; Wilson, Andrew S.

    2003-01-01

    We present an analysis of the compact X-ray source population in the Seyfert 2 galaxy NGC 1068, imaged with a approx. 50 ks Chandra observation. We find a total of 84 compact sources on the S3 chip, of which 66 are located within the 25.0 B-mag/arcsec isophote of the galactic disk of NGC 1068. Spectra have been obtained for the 21 sources with at least 50 counts and modeled with both multicolor disk blackbody and power-law models. The power-law model provides the better description of the spectrum for 18 of these sources. For fainter sources, the spectral index has been estimated from the hardness ratio. Five sources have 0.4 - 8 keV intrinsic luminosities greater than 10(exp 39)ergs/ s, assuming that their emission is isotropic and that they are associated with NGC 1068. We refer to these sources as intermediate-luminosity X-ray objects (ISOs). If these five sources are X-ray binaries accreting with luminosities that are both sub-Eddington and isotropic, then the implied source masses are approx greater than 7 solar mass, and so they are inferred to be black holes. Most of the spectrally modeled sources have spectral shapes similar to Galactic black hole candidates. However, the brightest compact source in NGC 1068 has a spectrum that is much harder than that found in Galactic black hole candidates and other ISOs. The brightest source also shows large amplitude variability on both short-term and long-term timescales, with the count rate possibly decreasing by a factor of 2 in approx. 2 ks during our Chundra observation, and the source flux decreasing by a factor of 5 between our observation and the grating observations taken just over 9 months later. The ratio of the number of sources with luminosities greater than 2.1 x 10(exp 38) ergs/s in the 0.4 - 8 keV band to the rate of massive (greater than 5 solar mass) star formation is the same, to within a factor of 2, for NGC 1068, the Antennae, NGC 5194 (the main galaxy in M51), and the Circinus galaxy. This suggests

  16. OT2_peisenha_2: The Most Luminous Obscured Galaxies and Quasars Revealed by WISE and Herschel

    NASA Astrophysics Data System (ADS)

    Eisenhardt, P.

    2011-09-01

    NASA's Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at 3.4, 4.6, 12 and 22 microns (W1, W2, W3, and W4), reaching sensitivities hundreds of times deeper than IRAS. We have used WISE photometry to select an all-sky sample of objects which are extremely luminous. The objects are prominent in W4, but faint or undetected in W1 and W2 (W12drops). Followup spectroscopy of ~ 100 sources shows over 70% of W12drops have redshifts > 1.6, which with OT1 PACS and SPIRE photometry of 27 sources leads to over 1E13 solar luminosities, with ~ 10% exceeding 1E14 solar luminosities. High resolution adaptive optics imaging shows these objects are unlensed. We request 47.3 hours of Herschel time to complete the all-sky sample of the brightest 185 W12 drops, fulfilling the primary WISE objective of finding the most extreme luminous IR galaxies in the Universe. These superlative objects will be the most fruitful for detailed studies of the physics of star formation, AGN fueling, and feedback in the most active galaxies.

  17. Transcending boundaries with Ira Hirsh

    NASA Astrophysics Data System (ADS)

    Singh, Punita G.

    2002-05-01

    Ira Hirsh has made many contributions to various fields of acoustics from speech, hearing, psychological and physiological acoustics, to musical and architectural acoustics. It was a privilege for me to have been his student in all these areas, and to have had him as a guide through masters and doctoral degree programs that focused on topics that lie at the boundaries connecting these disciplines. Ira was not a prescriptive advisor, imposing particular research topics or procedures on his graduate students. Rather, he encouraged originality, innovation, and personal goal setting. He would subtly suggest starting points and provide landmarks as references, rather than explicit directions leading to them. One had to navigate the path by ones own wits. This approach encouraged lateral, out-of-the box thinking, while also leading to respectful appreciation of historic trajectories in scientific research. During our time together, we worked on several aspects of music, including, rhythm, melody, pitch, and timber perception. Some of this work will be recapitulated, highlighting Ira's role in its exposition and development. His multidimensional personality, astute insights, colorful remarks, wry humor, care, and concern are qualities to be cherished-beyond the boundaries of campus, city, country, and contemporaneity.

  18. Dust near luminous ultraviolet stars

    NASA Technical Reports Server (NTRS)

    Henry, Richard C.

    1992-01-01

    More than 700 luminous stars in the infrared astronomical satellite (IRAS) Skyflux plates were examined for the presence of dust heated by a nearby star. This dust may be distinguished from the ubiquitous cool cirrus by its higher temperature and thus enhanced 60 micron emission. More than 120 dust clouds were found around only 106 of the stars with a volume filling factor of 0.006 and an intercloud separation of 46 pc. A region of dust smoothly distributed through the volume of space heated by the star could not be found and hence an upper limit of 0.05 cm(exp -3) is placed on the equivalent gas density in the intercloud regions. The clouds have an average density of 0.22 cm(exp -3) and a radius of 1.9 pc, albeit with wide variations in their properties. Two different scale heights of 140 and 540 pc were found. This was interpreted as evidence for different distributions of dust in and out of the galactic disk.

  19. Far-infrared observations of a luminous dust-shrouded source in the nucleus of NGC 4945

    NASA Technical Reports Server (NTRS)

    Brock, David; Joy, Marshall; Lester, Daniel F.; Harvey, Paul M.; Ellis, H. Benton, Jr.

    1988-01-01

    High-resolution far-infrared observations of the galaxy NGC 4945 have been obtained from the Kuiper Airborne Observatory. Using new observational techniques and nonlinear deconvolution routines, it is found that virtually all of the far-infrared luminosity originates from a nuclear source no larger than 12 arcsec x 9 arcsec (225 pc x 170 pc) in extent. This size constraint, coupled with the far-infrared dust temperature, indicates that the source is deeply embedded in dust: the lower limit for the 100 micron optical depth is 0.35, which is by far the largest yet measured in an external galaxy. Published optical spectra of NGC 4945 reveal a heavily obscured nonthermal source which exhibits broad line profiles typical of a Seyfert 2 active nucleus; it is concluded that the far-infrared emission is probably due to thermal radiation from dust grains surrounding the nonthermal nuclear source. A compact cluster of massive young stars may also contribute to the infrared luminosity, but the evidence for such star-forming activity is weak.

  20. An Ultraviolet-Excess Optical Candidate for the Luminous Globular Cluster X-Ray Source in NGC 1851

    NASA Technical Reports Server (NTRS)

    Deutsch, Eric W.; Anderson, Scott F.; Margon, Bruce; Downes, Ronald A.

    1996-01-01

    The intense, bursting X-ray source in the globular cluster NGC 1851 was one of the first cluster sources discovered, but has remained optically unidentified for 25 years. We report here on results from Hubble Space Telescope WFPC2 multicolor images in NGC 1851. Our high spatial resolution images resolve approximately 200 objects in the 3 minute radius Einstein X-ray error circle, 40 times as many as in previous ground-based work. A color-magnitude diagram of the cluster clearly reveals a markedly UV-excess object with B approximately 21, (U - B) approximately -0.9, only 2 minutes from the X-ray position. The UV-excess candidate is 0.12 minutes distant from a second, unremarkable star that is 0.5 mag brighter in B; thus ground-based studies of this field are probably impractical. Three other UV-excess objects are also present among the approximately 16,000 objects in the surveyed region of the cluster, leaving an approximately 5% probability that a UV-excess object has fallen in the X-ray error circle by chance. No variability of the candidate is seen in these data, although a more complete study is required. If this object is in fact the counterpart of the X-ray source, previous inferences that some globular cluster X-ray sources are optically subluminous with respect to low-mass X-ray binaries in the field are now strengthened.

  1. An IRAS-based search for new Dusty Late-Type WC Wolf-Rayet stars

    NASA Technical Reports Server (NTRS)

    Cohen, Martin

    1995-01-01

    I have examined all Infrared Astronomical Satellite (IRAS) data relevant to the 173 Galactic Wolf-Rayet (W-R) stars in an updated catalog, including the 13 stars newly discovered by Shara and coworkers. Using the W-R coordinates in these lists, I have examined the IRAS Point Source Catalog (PSC), the Faint Source Catalog, and the Faint Source Reject Catalog, and have generated one-dimensional spatial profiles ('ADDSCANs') and two-dimensional full-resolution images ('FRESCOs'). The goal was to assemble the best set of observed IRAS color indices for different W-R types, in particular for known dusty late-type WC Wolf-Rayet (WCL) objects. I have also unsuccessfully sought differences in IRAS colors and absolute magnitudes between single and binary W-R stars. The color indices for the entire ensemble of W-R stars define zones in the IRAS color-color plane. By searching the PSC for otherwise unassociated sources that satisfy these colors, I have identified potential new W-R candidates, perhaps too faint to have been recognized in previous optical searches. I have extracted these candidates' IRAS low-resolution spectrometer (LRS) data and compared the spectra with the highly characteristic LRS shape for known dusty WCL stars. The 13 surviving candidates must now be examined by optical spectroscopy. This work represents a much more rigorous and exhaustive version of the LRS study that identified IRAS 17380 - 3031 (WR98a) as the first new W-R (WC9) star discovered by IRAS. This search should have detected dusty WCL stars to a distance of 7.0 kpc from the Sun, for the absolute value of l greater than 30 deg, and to 2.9 kpc even in the innermost Galaxy. For free-free-dominated W-R stars the corresponding distances are 2.5 and 1.0 kpc, respectively.

  2. Observations of Luminous Infrared Galaxies with Herschel

    NASA Astrophysics Data System (ADS)

    Armus, Lee

    2014-01-01

    A major result of the IRAS survey was the discovery of a large population of luminous infrared galaxies (LIRGs) which emit a significant fraction of their bolometric luminosity in the far-infrared. LIRGs cover the full range of morphologies from isolated disk galaxies, to advanced mergers, exhibiting enhanced star-formation rates and a higher fraction of Active Galactic Nuclei (AGN) compared to less luminous galaxies. A detailed study of low-redshift LIRGs is critical for our understanding of the cosmic evolution of galaxies and black holes, since LIRGs comprise the bulk of the cosmic far-infrared background and dominate the star-formation between 0.5 < z < 1. With ISO, it was possible to measure the full suite of infrared diagnostic lines in local normal and luminous infrared galaxies for the first time, but samples were small and observations challenging. With Herschel, we have been able to study large samples of low-redshift LIRGs, and even probe the physical conditions in poweful starburst galaxies out to significant redshifts. By combining the Herschel data with those from Spitzer, it is now possible to understand the heating and cooling of the dust and gas in complete samples of LIRGs for the first time. I will review recent results from a number of GTO, OTKP and GO programs in an attempt to summarize the advances we have made in understanding star formation and black hole accretion in LIRGs as a direct result of the Herschel mission.

  3. Spatial deconvolution of IRAS galaxies at 60 UM

    NASA Technical Reports Server (NTRS)

    Low, Frank J.

    1987-01-01

    Using IRAS in a slow scan observing mode to increase the spatial sampling rate and a deconvolution analysis to increase the spatial resolution, several bright galaxies were resolved at 60 micron. Preliminary results for M 82, NGC 1068, NGC 3079 and NGC 2623 show partially resolved emission from 10 to 26 arcsec., full width at half maximum, and extended emission from 30 to 90 arcsec. from the center. In addition, the interacting system, Arp 82, along with Mark 231 and Arp 220 were studied using the program ADDSCAN to average all available survey mode observations. The Arp 82 system is well resolved after deconvolution and its brighter component is extended; the two most luminous objects are not resolved with an upper limit of 15 arcsec. for Arp 220.

  4. Infrared Astronomical Satellite /IRAS/ Scientific Data Analysis System

    NASA Technical Reports Server (NTRS)

    Duxbury, J. H.; Soifer, B. T.

    1980-01-01

    The Infrared Astronomical Satellite (IRAS), to be launched in 1982, is discussed. It will systematically survey the entire sky over a large percentage of the infrared spectrum, in the wavelength region of 8 to 120 microns, at sensitivities a hundred times greater than previously achieved from high-altitude observatories, aircraft, balloons or sounding rockets. The Scientific Data Analysis System (SDAS), an off-line data processing facility, is examined. Its primary function is to produce a catalog of inertially fixed infrared-emitting point sources (mainly stars and galaxies) observed during the IRAS survey. Details for source detection and confirmation are given. It is estimated that the catalog will contain approximately a million objects having a brightness of 10 amtowatts per square centimeter or greater; 125,000 SDAS detections, if spurious events of signal-to-noise ratios greater than 2.5 are included, will be made every day.

  5. Monsters and babies from the first / iras survey

    NASA Astrophysics Data System (ADS)

    van Breugel, Wil

    Radio continuum emission at cm wavelengths is relatively little affected by extinction. When combined with far-infrared (FIR) surveys this provides for a convenient and unbiased method to select (radio-loud) AGN and starbursts deeply embedded in gas and dust-rich galaxies. Such radio-selected FIR samples are useful for detailed investigations of the complex relationships between (radio) galaxy and starburst activity, and to determine whether ULIRGs are powered by hidden quasars (monsters) or young stars (babies). We present the results of a large program to obtain identifications and spectra of radio-selected, optically faint IRAS/FSC objects using the FIRST/VLA 20 cm survey (Becker, White and Helfand 1995). These objects are all radio- `quiet' in the sense that their radio power / FIR luminosities follow the well-known radio/FIR relationship for star forming galaxies. We compare these results to a previous study by our group of a sample of radio-`loud' IRAS/FSC ULIRGs selected from the Texas 365 MHz survey (Douglas etal. 1996). Many of these objects also show evidence for dominant, A-type stellar populations, as well as high ionization lines usually associated with AGN. These radio-loud ULIRGs have properties intermediate between those of starbursts and quasars, suggesting a possible evolutionary connection. Deep Keck spectroscopic observations of three ULIRGs from these samples are presented, including high signal-to-noise spectropolarimetry. The polarimetry observations failed to show evidence of a hidden quasar in polarized (scattered) light in the two systems in which the stellar light was dominated by A-type stars. Although observations of a larger sample would be needed to allow a general conclusion, our current data suggest that a large fraction of ULIRGs may be powered by luminous starbursts, not by hidden, luminous AGN (quasars).

  6. Duodenal luminal nutrient sensing

    PubMed Central

    Rønnestad, Ivar; Akiba, Yasutada; Kaji, Izumi; Kaunitz, Jonathan D

    2016-01-01

    The gastrointestinal mucosa is exposed to numerous chemical substances and microorganisms, including macronutrients, micronutrients, bacteria, endogenous ions, and proteins. The regulation of mucosal protection, digestion, absorption and motility is signaled in part by luminal solutes. Therefore, luminal chemosensing is an important mechanism enabling the mucosa to monitor luminal conditions, such as pH, ion concentrations, nutrient quantity, and microflora. The duodenal mucosa shares luminal nutrient receptors with lingual taste receptors in order to detect the five basic tastes, in addition to essential nutrients, and unwanted chemicals. The recent ‘de-orphanization’ of nutrient sensing G protein-coupled receptors provides an essential component of the mechanism by which the mucosa senses luminal nutrients. In this review, we will update the mechanisms of and underlying physiological and pathological roles in luminal nutrient sensing, with a main focus on the duodenal mucosa. PMID:25113991

  7. Fourier removal of stripe artifacts in IRAS images

    NASA Technical Reports Server (NTRS)

    Van Buren, Dave

    1987-01-01

    By working in the Fourier plane, approximate removal of stripe artifacts in IRAS images can be effected. The image of interest is smoothed and subtracted from the original, giving the high-spatial-frequency part. This 'filtered' image is then clipped to remove point sources and then Fourier transformed. Subtracting the Fourier components contributing to the stripes in this image from the Fourier transform of the original and transforming back to the image plane yields substantial removal of the stripes.

  8. An Extremely Luminous and Variable Ultraluminous X-ray Source in the Outskirts of Circinus Observed with Nustar

    NASA Technical Reports Server (NTRS)

    Walton, D. J.; Fuerst, F.; Harrison, F.; Stern, D.; Bachetti, M.; Barret, D.; Bauer, F.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Fabian, A. C.; Grefenstette, B. W.; Hailey, C. J.; Madsen, K. K.; Miller, J. M.; Ptak, Andrew Francis; Rana, V.; Webb, N. A.; Zhang, W. W.

    2013-01-01

    Following a serendipitous detection with the Nuclear Spectroscopic Telescope Array (NuSTAR), we present a multiepoch spectral and temporal analysis of an extreme ultraluminous X-ray source (ULX) located in the outskirts of the Circinus galaxy, hereafter Circinus ULX5, including coordinated XMM-Newton+NuSTAR follow-up observations. The NuSTAR data presented here represent one of the first instances of a ULX reliably detected at hard (E greater than 10 keV) X-rays. CircinusULX5is variable on long time scales by at least a factor of approx. 5 in flux, and was caught in a historically bright state during our 2013 observations (0.3-30.0 keV luminosity of 1.6 × 10(exp 40) erg s(exp-1)). During this epoch, the source displayed a curved 3-10 keV spectrum, broadly similar to other bright ULXs. Although pure thermal models result in a high energy excess in the NuSTAR data, this excess is too weak to be modeled with the disk reflection interpretation previously proposed to explain the 3-10 keV curvature in other ULXs. In addition to flux variability, clear spectral variability is also observed. While in many cases the interpretation of spectral components in ULXs is uncertain, the spectral and temporal properties of all the high quality data sets currently available strongly support a simple disk-corona model reminiscent of that invoked for Galactic binaries, with the accretion disk becoming more prominent as the luminosity increases. However, although the disk temperature and luminosity are well correlated across all time scales currently probed, the observed luminosity follows L alpha T (exp 1.70+/-0.17), flatter than expected for simple blackbody radiation. The spectral variability displayed here is highly reminiscent of that observed from known Galactic black hole binaries (BHBs) at high luminosities. This comparison implies a black hole mass of approx. 90M for Circinus ULX5. However, given the diverse behavior observed from Galactic BHB accretion disks, this mass

  9. An extremely luminous and variable ultraluminous X-ray source in the outskirts of Circinus observed with NuSTAR

    SciTech Connect

    Walton, D. J.; Fuerst, F.; Harrison, F.; Stern, D.; Grefenstette, B. W.; Madsen, K. K.; Rana, V.; Bachetti, M.; Barret, D.; Webb, N. A.; Bauer, F.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Fabian, A. C.; Hailey, C. J.; Miller, J. M.; Ptak, A.; Zhang, W. W.

    2013-12-20

    Following a serendipitous detection with the Nuclear Spectroscopic Telescope Array (NuSTAR), we present a multi-epoch spectral and temporal analysis of an extreme ultraluminous X-ray source (ULX) located in the outskirts of the Circinus galaxy, hereafter Circinus ULX5, including coordinated XMM-Newton+NuSTAR follow-up observations. The NuSTAR data presented here represent one of the first instances of a ULX reliably detected at hard (E > 10 keV) X-rays. Circinus ULX5 is variable on long time scales by at least a factor of ∼5 in flux, and was caught in a historically bright state during our 2013 observations (0.3-30.0 keV luminosity of 1.6 × 10{sup 40} erg s{sup –1}). During this epoch, the source displayed a curved 3-10 keV spectrum, broadly similar to other bright ULXs. Although pure thermal models result in a high energy excess in the NuSTAR data, this excess is too weak to be modeled with the disk reflection interpretation previously proposed to explain the 3-10 keV curvature in other ULXs. In addition to flux variability, clear spectral variability is also observed. While in many cases the interpretation of spectral components in ULXs is uncertain, the spectral and temporal properties of all the high quality data sets currently available strongly support a simple disk-corona model reminiscent of that invoked for Galactic binaries, with the accretion disk becoming more prominent as the luminosity increases. However, although the disk temperature and luminosity are well correlated across all time scales currently probed, the observed luminosity follows L∝T {sup 1.70±0.17}, flatter than expected for simple blackbody radiation. The spectral variability displayed here is highly reminiscent of that observed from known Galactic black hole binaries (BHBs) at high luminosities. This comparison implies a black hole mass of ∼90 M {sub ☉} for Circinus ULX5. However, given the diverse behavior observed from Galactic BHB accretion disks, this mass estimate is

  10. IUE/IRA system description

    NASA Technical Reports Server (NTRS)

    Jennings, J.

    1977-01-01

    The IUE/IRA rate sensor system designed to meet the requirements of the International Ultraviolet Explorer spacecraft mission is described. The system consists of the sensor unit containing six rate sensor modules and the electronic control unit containing the rate sensor support electronics and the command/control circuitry. The inertial reference assembly formed by the combined units will provide spacecraft rate information for use in the stabilization and control system. The system is described in terms of functional description, operation redundancy performance, mechanical interface, and electrical interface. Test data obtained from the flight unit are summarized.

  11. The IRAS Galaxy Atlas (IGA)

    NASA Technical Reports Server (NTRS)

    Prince, Thomas A.; Oliversen, R. (Technical Monitor)

    1999-01-01

    In 1993 we proposed a project to NASA having the goal of producing a new infrared map of our Galaxy. In particular, we proposed to reprocess the IRAS data taken in the early 1980's using modern image processing algorithms and the large Intel parallel computers of the Center for Advanced Computing Research, (at that time called the Caltech Concurrent Supercomputing Facilities - CCSF). The rationale was simple: what took approximately 100 days on a typical workstation would take less than a day on the multi-processor parallel computers, thus making a high-resolution infrared atlas of the Galaxy feasible.

  12. IRAS observations of irregular galaxies

    NASA Technical Reports Server (NTRS)

    Hunter, D.; Rice, W.; Gallagher, J.; Gillett, F.

    1987-01-01

    Normal irregular galaxies seem to be unusual in having vigorous star formation yet lacking the many dark nebulae typical of spirals. The Infrared Astronomy Satellite (IRAS) observations of a large sample of irregulars are used to explore the dust contents of these galaxies. Compared to normal spirals, the irregulars generally have higher L sub IR/L sub B ratios, warmer f(100)/f(60) dust color temperatures, and lower globally-averaged dust/gas ratios. The relationship between the infrared data and various global optical properties of the galaxies is discussed.

  13. FIRST VIEWS OF A NEARBY LIRG: STAR FORMATION AND MOLECULAR GAS IN IRAS 04296+2923

    SciTech Connect

    Meier, David S.; Turner, Jean L.; Tsai, Chao-Wei; Beck, Sara C.; Gorjian, Varoujan; Van Dyk, Schuyler D. E-mail: cwtsai@astro.ucla.ed E-mail: varoujan.gorjian@jpl.nasa.go

    2010-11-15

    We present a first look at the local luminous infrared galaxy (LIRG) IRAS 04296+2923. This barred spiral galaxy, overlooked because of its location behind the Taurus molecular cloud, is among the half dozen closest (D = 29 Mpc) LIRGs. More IR-luminous than either M82 or the Antennae, it may be the best local example of a nuclear starburst caused by bar-mediated secular evolution. We present Palomar J and Pa {beta} images, Very Large Array continuum maps from {lambda}= 20-1.3 cm, a subarcsecond Keck Long Wavelength Spectrometer image at 11.7 {mu}m and Owens Valley Millimeter Array CO(1-0), {sup 13}CO(1-0), and 2.7 mm continuum images. The J-band image reveals a symmetric barred spiral galaxy. Two bright, compact mid-infrared and radio sources in the nucleus mark a starburst that is energetically equivalent to {approx}10{sup 5} O7 stars, separated by {approx}<50 pc. This is probably a pair of young super star clusters, with estimated stellar masses of {approx}10{sup 7} M{sub sun} each. The nuclear starburst is forming stars at the rate of {approx}12 {+-} 6 M{sub sun} yr{sup -1}, or about half of the total star formation rate for the galaxy of {approx}25 {+-} 10 M{sub sun} yr{sup -1}. IRAS 04296+2923 is very bright in CO, and among the most gas-rich galaxies in the local universe. The {sup 12}CO luminosity of the inner half kpc is equivalent to that of the entire Milky Way. While the most intense CO emission is extended over a 15'' (2 kpc) diameter region, the nuclear starburst is confined to within 1''-2'' (150-250 pc) of the dynamical center. Based on masses obtained with {sup 13}CO, we find that the CO conversion factor in the nucleus is lower than the Galactic value, X {sup Gal}{sub CO} by a factor of three to four, typical of gas-rich spiral nuclei. The nuclear star formation efficiency (SFE) is {sup nuc}M{sub gas}/SFR{sup nuc} = 2.7 x 10{sup -8}yr{sup -1}, corresponding to a gas consumption timescale, {tau}{sup nuc}{sub SF} {approx} 4 x 10{sup 7} yr. The SFE is

  14. Discovery of the Candidate Off-nuclear Ultrasoft Hyper-luminous X-Ray Source 3XMM J141711.1+522541

    NASA Astrophysics Data System (ADS)

    Lin, Dacheng; Carrasco, Eleazar R.; Webb, Natalie A.; Irwin, Jimmy A.; Dupke, Renato; Romanowsky, Aaron J.; Ramirez-Ruiz, Enrico; Strader, Jay; Homan, Jeroen; Barret, Didier; Godet, Olivier

    2016-04-01

    We report the discovery of an off-nuclear ultrasoft hyper-luminous X-ray source candidate 3XMM J141711.1+522541 in the inactive S0 galaxy SDSS J141711.07+522540.8 (z = 0.41827, dL = 2.3 Gpc) in the Extended Groth Strip. It is located at a projected offset of ∼1.″0 (5.2 kpc) from the nucleus of the galaxy and was serendipitously detected in five XMM-Newton observations in 2000 July. Two observations have enough counts and can be fitted with a standard thermal disk with an apparent inner disk temperature {{kT}}{MCD}∼ 0.13 {{keV}} and a 0.28–14.2 keV unabsorbed luminosity LX ∼ 4 × 1043 erg s‑1 in the source rest frame. The source was still detected in three Chandra observations in 2002 August, with similarly ultrasoft but fainter spectra (kTMCD ∼ 0.17 keV, LX ∼ 0.5 × 1043 erg s‑1). It was not detected in later observations, including two by Chandra in 2005 October, one by XMM-Newton in 2014 January, and two by Chandra in 2014 September–October, implying a long-term flux variation factor of >14. Therefore the source could be a transient with an outburst in 2000–2002. It has a faint optical counterpart candidate, with apparent magnitudes of mF606W = 26.3 AB mag and mF814W = 25.5 AB mag in 2004 December (implying an absolute V-band magnitude of ∼‑15.9 AB mag). We discuss various explanations for the source and find that it is best explained as a massive black hole (BH) embedded in the nucleus of a possibly stripped satellite galaxy, with the X-ray outburst due to tidal disruption of a surrounding star by the BH. The BH mass is ∼105 M⊙, assuming the peak X-ray luminosity at around the Eddington limit.

  15. IRAS colors of carbon stars - An optical spectroscopic test

    SciTech Connect

    Cohen, M.; Wainscoat, R.J.; Walker, H.J.; Volk, K.; Schwartz, D.E.; Search for Extraterrestrial Intelligence Institute, Los Altos, CA )

    1989-06-01

    Optical spectra are obtained of 57 photographic counterparts to IRAS sources not previously studied spectroscopically, and expected on the basis of their IRAS colors to be M or C type stars. Confirmed carbon stars are found only in a restricted range of 12-25 index, and constitute a striking vertical sequence in the 12-25-60 micron color-color diagram. This sequence is in accord with evolutionary models for AGB stars that convert M into C stars by dredge-up, and follow loops in the color-color plane. Optically visible and optically invisible carbon stars occupy different color-color locations consistent with their representations of different evolutionary states in the life of relatively low-mass stars. 16 refs.

  16. Automatic classification of spectra from the Infrared Astronomical Satellite (IRAS)

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter; Stutz, John; Self, Matthew; Taylor, William; Goebel, John; Volk, Kevin; Walker, Helen

    1989-01-01

    A new classification of Infrared spectra collected by the Infrared Astronomical Satellite (IRAS) is presented. The spectral classes were discovered automatically by a program called Auto Class 2. This program is a method for discovering (inducing) classes from a data base, utilizing a Bayesian probability approach. These classes can be used to give insight into the patterns that occur in the particular domain, in this case, infrared astronomical spectroscopy. The classified spectra are the entire Low Resolution Spectra (LRS) Atlas of 5,425 sources. There are seventy-seven classes in this classification and these in turn were meta-classified to produce nine meta-classes. The classification is presented as spectral plots, IRAS color-color plots, galactic distribution plots and class commentaries. Cross-reference tables, listing the sources by IRAS name and by Auto Class class, are also given. These classes show some of the well known classes, such as the black-body class, and silicate emission classes, but many other classes were unsuspected, while others show important subtle differences within the well known classes.

  17. An IRAS-Based Search for New Dusty Late-Type WC Wolf-Rayet Stars

    NASA Technical Reports Server (NTRS)

    Cohen, Martin

    1995-01-01

    I have examined all Infrared Astronomical Satellite (IRAS) data relevant to the 173 Galactic Wolf-Rayet (W-R) stars in an updated catalog, including the 13 stars newly discovered by Shara and coworkers. Using the W-R coordinates in these lists, I have examined the IRAS Point Source Catalog (PSC), the Faint Source Catalog, and the Faint Source Reject Catalog, and have generated one-dimensional spatial profiles, 'ADDSCANs', and two-dimensional full-resolution images, 'FRESCOS'. The goal was to assemble the best set of observed IRAS color indices for different W-R types, in particular for known dusty late-type WC Wolf-Rayet (WCL) objects. I have also unsuccessfully sought differences in IRAS colors and absolute magnitudes between single and binary W-R stars. The color indices for the entire ensemble of W-R stars define zones in the IRAS color-color ([12] - [25], [25] - [60])-plane. By searching the PSC for otherwise unassociated sources that satisfy these colors, I have identified potential new W-R candidates, perhaps too faint to have been recognized in previous optical searches. I have extracted these candidates' IRAS low-resolution spectrometer (LRS) data and compared the spectra with the highly characteristic LRS shape for known dusty WCL stars. The 13 surviving candidates must now be ex amined by optical spectroscopy. This work represents a much more rigorous and exhaustive version of the LRS study that identified IRAS 17380 - 3031 (WR98a) as the first new W-R (WC9) star discovered by IPAS. This search should have detected dusty WCL stars to a distance of 7.0 kpc from the Sun, for l is greater than 30 degrees, and to 2.9 kpc even in the innermost galaxy. For free-free-dominated W-R stars the corresponding distances are 2.5 and 1.0 kpc, respectively.

  18. The complex high-mass star-forming region IRAS 15507-5359

    NASA Astrophysics Data System (ADS)

    Persi, P.; Tapia, M.; Roth, M.; Elia, D.; López-Vázquez, J. A.

    2016-06-01

    The far-infrared IRAS 15507-5359 source is known to be a medium-mass star-forming region associated with a compact H II region and a near-infrared embedded cluster. We present a survey of infrared-calibrated images ranging from 1.2 to 500 μm obtained with the Baade telescope at Las Campanas Observatory, and the Herschel space telescope with additional archive Spitzer data. We confirm the distance to the complex to be 5.0 kpc. Three Herschel far-infrared sources are found, I, II, III, identified with dense cores at different evolutionary stages. One (III) is a starless infrared dark cloud showing, near its edge, two infrared reflection nebulae (R1) and (R2) with dispersed young stellar populations, including a knot of shocked H2 line emission. Both show considerable polycyclic aromatic hydrocarbon emission. Core II has associated a radio H II region and a deeply embedded one-million-year-old cluster (Cl 1) that contains more than 45 young stellar objects, reddened by at least 20 visual magnitudes. About 20 per cent of them show considerable infrared excess emission. Core I appears void of a near-infrared population, and coincides with a long emission bar that resembles a photodissociation front. We determine the properties of the two most luminous Class I sources in the region by fitting models of young stars with accreting discs and envelopes to their 1-500 μm spectral energy distributions. This is another example of a medium-mass region with at least three well-defined active centres of star formation separated by about 1 pc and at different evolutionary stages.

  19. 26 CFR 1.408A-2 - Establishing Roth IRAs.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... established with any bank, insurance company, or other person authorized in accordance with § 1.408-2(e) to... effect of a surviving spouse of a Roth IRA owner treating an IRA as his or her own? A-4. If the surviving spouse of a Roth IRA owner treats a Roth IRA as his or her own as of a date, the Roth IRA is treated...

  20. Spatial analysis of IRAS observations of nearby spirals

    NASA Technical Reports Server (NTRS)

    Ball, Roger; Lo, R. Y.

    1990-01-01

    The unbiased survey of the infrared sky carried out by the Infrared Astronomy Satellite (IRAS) satellite has greatly accelerated advances in understanding the dust component of our own and external galaxies. However, most extragalactic studies to date have been based on the IRAS Point Source Catalog (PSC), which has two serious limitations. First, in sources where a significant fraction of the flux is extended, significant errors may result from using PSC fluxes in comparative studies, and these errors could be systematic if the tendency to be non-pointlike depends on physical properties of the galaxy. Additionally, use of PSC fluxes rules out any direct investigation of the spatial distribution of the IRAS emission from disks in external galaxies. Since work on the Galactic IRAS results has shown that very different physical processes can make varying contributions to the observed flux, it is important to look at a wide sample of galaxies with some spatial resolution to study the relative dominance of these processes under a variety of conditions. Here, researchers report on work they are doing to carry out this program for many nearby spirals, using an analysis package that was developed for this purpose. Researchers carried out analysis for a sample of 121 nearby spirals. The fraction of the flux contained in a point source varies from 0 to 1 across the sample, all of which are well resolved at their nominal optical diameters. There is no evidence that the galaxies of smaller angular size are less likely to be resolved by IRAS at this level. The program gives results which are quite repeatable from scan to scan; the fraction f (point source flux over total flux) at 60 microns has typical errors of 0.03 when different scans are combined. Approximately two-thirds of the sample have more flux in the extended than in the nuclear component. There is a tendency for earlier-type spirals to be less centrally concentrated, but this effect is slight and the degree of

  1. 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.

  2. High-velocity Interstellar Bullets in IRAS 05506+2414: A Very Young Protostar

    NASA Technical Reports Server (NTRS)

    Sahai, Raghvendra; Claussen, Mark; Sanchez Contreras, Carmen; Morris, Mark; Sarkar, Geetanjali

    2008-01-01

    We have made a serendipitous discovery of an enigmatic outflow source, IRAS 05506+2414 (hereafter IRAS 05506), as part of a multiwavelength survey of pre-planetary nebulae (PPNs). The HST optical and near-infrared images show a bright compact central source with a jet-like extension, and a fan-like spray of high-velocity (with radial velocities up to 350 km/s) elongated knots which appear to emanate from it. These structures are possibly analogous to the near-IR bullets'' seen in the Orion Nebula. Interferometric observations at 2.6 mm show the presence of a continuum source and a high-velocity CO outflow, which is aligned with the optical jet structure. IRAS 05506 is most likely not a PPN. We find extended NH3 (1,1) emission toward IRAS 05506; these data, together with the combined presence of far-IR emission, H2O and OH masers, and CO and CS J=2-1 emission, strongly argue for a dense, dusty star-forming core associated with IRAS 05506. IRAS 05506 is probably an intermediate-mass or massive protostar, and the very short timescale (200 yr) of its outflows indicates that it is very young. If IRAS 05506 is a massive star, then the lack of radio continuum and the late G to early K spectral type we find from our optical spectra imply that in this object we are witnessing the earliest stages of its life, while its temperature is still too low to provide sufficient UV flux for ionization.

  3. EXOMARS IRAS (DOSE) radiation measurements.

    NASA Astrophysics Data System (ADS)

    Federico, C.; Di Lellis, A. M.; Fonte, S.; Pauselli, C.; Reitz, G.; Beaujean, R.

    The characterization and the study of the radiations on their interaction with organic matter is of great interest in view of the human exploration on Mars. The Ionizing RAdiation Sensor (IRAS) selected in the frame of the ExoMars/Pasteur ESA mission is a lightweight particle spectrometer combining various techniques of radiation detection in space. It characterizes the first time the radiation environment on the Mars surface, and provide dose and dose equivalent rates as precursor information absolutely necessary to develop ways to mitigate the radiation risks for future human exploration on Mars. The Martian radiation levels are much higher than those found on Earth and they are relatively low for space. Measurements on the surface will show if they are similar or not to those seen in orbit (modified by the presence of ``albedo'' neutrons produced in the regolith and by the thin Martian atmosphere). IRAS consists of a telescope based on segmented silicon detectors of about 40\\userk\\milli\\metre\\user;k diameter and 300\\user;k\\micro\\metre\\user;k thickness, a segmented organic scintillator, and of a thermoluminescence dosimeter. The telescope will continuously monitor temporal variation of the particle count rate, the dose rate, particle and LET (Linear Energy Transfer) spectra. Tissue equivalent BC430 scintillator material will be used to measure the neutron dose. Neutrons are selected by a criteria requiring no signal in the anti-coincidence. Last, the passive thermoluminescence dosimeter, based on LiF:Mg detectors, regardless the on board operation timing, will measure the total dose accumulated during the exposure period and due to beta and gamma radiation, with a responsivity very close to that of a human tissue.

  4. A survey of IRAS data on 41 classical novae

    NASA Technical Reports Server (NTRS)

    Harrison, T. E.; Gehrz, R. D.

    1988-01-01

    The IRAS database has been searched for detections of 41 classical novae using coadditions of survey scans; 15 were detected. IRAS temporal observations of novae in outburst are discussed. The observed long-wavelength infrared distributions of DQ Her, and possibly HR Del, can be explained by emission from small (a of about 0.1 microns) dust grains heated by the central object. An alternative explanation for the energy distributions of DQ Her and HR Del is emission from fine-structure lines. FH Ser and LW Ser display energy distributions that have color temperatures much too hot to be due to heating of dust by the central source in any plausible scenario. Line emission is probably the best explanation of their observed energy distributions. The novae NQ Vul and LV Vul have energy distributions that may be contaminated by emission from galactic cirrus. The unusual object PL 1547.3-5612 exhibits an energy distribution that does not resemble those of planetary nebulae or other novae detected in this sample. An IRAS low-resolution spectrum of RR Tel shows the 10-micron silicate emission feature.

  5. Galaxy evolution and large-scale structure in the far-infrared. I - IRAS pointed observations

    NASA Astrophysics Data System (ADS)

    Lonsdale, Carol J.; Hacking, Perry B.

    1989-04-01

    Redshifts for 66 galaxies were obtained from a sample of 93 60-micron sources detected serendipitously in 22 IRAS deep pointed observations, covering a total area of 18.4 sq deg. The flux density limit of this survey is 150 mJy, 4 times fainter than the IRAS Point Source Catalog (PSC). The luminosity function is similar in shape with those previously published for samples selected from the PSC, with a median redshift of 0.048 for the fainter sample, but shifted to higher space densities. There is evidence that some of the excess number counts in the deeper sample can be explained in terms of a large-scale density enhancement beyond the Pavo-Indus supercluster. In addition, the faintest counts in the new sample confirm the result of Hacking et al. (1989) that faint IRAS 60-micron source counts lie significantly in excess of an extrapolation of the PSC counts assuming no luminosity or density evolution.

  6. Proper Motions of Water Masers within 1 AU of IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Wootten, A.; Marvel, K. B.; Claussen, M.; Wilking, B.

    1999-12-01

    Water masers can be used to trace gas motions in a variety of sources including evolved stars and stars undergoing formation. Recent observations of the water masers associated with two young stellar objects, IRAS 05413-0104 (aka HH212) and S106FIR (Claussen et al 1998 ApJ 507, L79, Furuya et al 1999), have shown that water masers form in shocked gas associated with bipolar outflows from the central forming star. Recent observations (Imai et al. 1999, PASJ 51, 473) have led to the claim that the masers in IRAS 16293-2422 are associated with infalling, rotating gas associated with a circum-protostellar disk. We present proper motion measurements using four epochs of observation with the Very Long Baseline Array, which clearly show proper motions directed away from the central source in IRAS 16293-2422. These motions contradict the expected proper motions for an infalling-rotating gas model for this source.

  7. Galaxy evolution and large-scale structure in the far-infrared. I - IRAS pointed observations

    NASA Technical Reports Server (NTRS)

    Lonsdale, Carol J.; Hacking, Perry B.

    1989-01-01

    Redshifts for 66 galaxies were obtained from a sample of 93 60-micron sources detected serendipitously in 22 IRAS deep pointed observations, covering a total area of 18.4 sq deg. The flux density limit of this survey is 150 mJy, 4 times fainter than the IRAS Point Source Catalog (PSC). The luminosity function is similar in shape with those previously published for samples selected from the PSC, with a median redshift of 0.048 for the fainter sample, but shifted to higher space densities. There is evidence that some of the excess number counts in the deeper sample can be explained in terms of a large-scale density enhancement beyond the Pavo-Indus supercluster. In addition, the faintest counts in the new sample confirm the result of Hacking et al. (1989) that faint IRAS 60-micron source counts lie significantly in excess of an extrapolation of the PSC counts assuming no luminosity or density evolution.

  8. A young bipolar outflow from IRAS15398-3359

    NASA Astrophysics Data System (ADS)

    Bjerkeli, Per; Jørgensen, Jes K.

    2015-08-01

    The Class 0 protostar IRAS 15398-3359 is located in the Lupus I cloud at a distance of 155 pc. The source is known to harbour a molecular outflow, but the region has not attracted much interest until recently. IRAS 15398 is known to show interesting chemical signatures and being one of the very nearby, young outflow sources makes it an excellent target for detailed studies of the gas kinematics of different species.We present observations of several molecular species, carried out with the Submillimeter Array and ALMA, towards the IRAS 15398 outflow. The analysis of CO emission show obvious signs of episodic mass ejections, with a dynamical time scale between the knots in the jet, of the order 100 years. This is consistent with recent ALMA results where luminosity outbursts are estimated to occur on similar time-scales. The physical properties of the outflow, such as mass, momentum, momentum rate, mechanical luminosity, kinetic energy and mass-loss rate are estimated at relatively low values. We argue that this source is of a very young age, possibly younger than ~1000 years. This is consistent with recent studies of the kinematics of the inner envelope/disk. The observed line profiles were compared to full 3D radiative transfer models of the source, constructed with the Line Modelling Engine (LIME). The observed line shapes can only be understood when considering several distinctly different physical components, viz. the outflow cavity, the infalling envelope and the surrounding cloud material. This allows us to put quantitative constraints on the kinematics of the material close to the central source.

  9. A Multiwavelength Study of the OH Megamaser Galaxy IRAS16399-0937

    NASA Astrophysics Data System (ADS)

    Sales, D.

    2015-09-01

    We present a multiwavelength study of the morphology and spectral energy distribution (SED) of the OH Megamaser galaxy (OHMG) IRAS16399- 0937, based on new HST ACS broad band (F814W) and emission line (Halpha+[NII]) images and archive data from HST, 2MASS, Spitzer, Herschel and the VLA (Fig. 1). This system has a double nucleus, whose northern (IRAS16399N) and southern (IRAS16399S) components have a projected separation of 6" (3.4 kpc) and have previously been optically identified as a Low Ionization Nuclear Emission Line Region (LINER) and Starburst (SB) nucleus, respectively. The nuclei are embedded in a tidally distorted common envelope, in which star formation activity is widespread, but mostly heavily obscured (Fig. 1). The infrared spectrum is dominated by strong polycyclic aromatic hydrocarbon (PAH) features, but deep silicate absorption and absorption features due to water ice and hydrogenated amorphous carbon grains are also present, and are strongest in the IRAS16399N nucleus (Fig. 2 and 3). The radio emission, including the compact component associated with the IRAS16399N nucleus, is generally consistent with star formation. The global star formation rate (SFR) is 20M(sun)/yr, with the two nuclei accounting for 40% of the total (Table 2). The 0.435 - 500 micron SED was fitted with a model including stellar, dusty+PAH ISM and AGN torus components using our new Markov Chain Monte Carlo code, clumpyDREAM (Fig. 4). The results indicate that the IRAS16399N nucleus contains an AGN of bolometric luminosity (Lbol 10^{44} ergs/s), which is deeply embedded in a quasi-spherical distribution of optically thick clumps with a covering fraction 1 (Table 1). We suggest that these clumps are the source of the OH megamaser emission in IRAS16399-0937. The high torus covering fraction precludes AGN photoionization as the origin of the LINER spectrum, however, the spectrum is consistent with shocks of velocity 100 - 200 km/s. The SED fits indicate SFRs of 2.9 and 2.4 M

  10. Critically evaluated/distributed database of IRAS LRS spectra

    NASA Technical Reports Server (NTRS)

    Stencel, R. E.

    1993-01-01

    Accomplishments under this grant effort include: successful scientific utilization of the IRAS Low Resolution Spectrometer (LRS) database of over 150,000 scans of 7-23 micron spectra for over 50,000 celestial sources; publication in refereed journal of an additional 486 critically evaluated spectra of sources brighter than 20 Jy, completing the LRS ATLAS (Olnon and Raimond 1986 A&A) uniformly to that level, and production of an additional 1,830 critically evaluated spectra of sources brighter than 10 Jy; creation and maintenance of on-line, remotely accessible LRS spectra of over 7500 sources; cooperation with Astrophysics Data System personnel for transitioning this LRS database to the ADS access system after funding for this project expires; and publication of research highlights, which include a systematic variation of the shapes of LRS silicate features among stars of differing IRAS broad-band colors, maser characteristics and light curve asymmetries, all correlated with the chemical and physical development and processing of solid phase materials, and preliminary evidence for silicate profile variations in individual stars as a function of visual light curve phase.

  11. Spatial studies of planetary nebulae with IRAS

    NASA Technical Reports Server (NTRS)

    Hawkins, G. W.; Zuckerman, B.

    1991-01-01

    The infrared sizes at the four IRAS wavelengths of 57 planetaries, most with 20-60 arcsec optical size, are derived from spatial deconvolution of one-dimensional survey mode scans. Survey observations from multiple detectors and hours confirmed (HCON) observations are combined to increase the sampling to a rate that is sufficient for successful deconvolution. The Richardson-Lucy deconvolution algorithm is used to obtain an increase in resolution of a factor of about 2 or 3 from the normal IRAS detector sizes of 45, 45, 90, and 180 arcsec at wavelengths 12, 25, 60, and 100 microns. Most of the planetaries deconvolve at 12 and 25 microns to sizes equal to or smaller than the optical size. Some of the planetaries with optical rings 60 arcsec or more in diameter show double-peaked IRAS profiles. Many, such as NGC 6720 and NGC 6543 show all infrared sizes equal to the optical size, while others indicate increasing infrared size with wavelength. Deconvolved IRAS profiles are presented for the 57 planetaries at nearly all wavelengths where IRAS flux densities are 1-2 Jy or higher.

  12. Spatial studies of planetary nebulae with IRAS

    SciTech Connect

    Hawkins, G.W.; Zuckerman, B. )

    1991-06-01

    The infrared sizes at the four IRAS wavelengths of 57 planetaries, most with 20-60 arcsec optical size, are derived from spatial deconvolution of one-dimensional survey mode scans. Survey observations from multiple detectors and hours confirmed (HCON) observations are combined to increase the sampling to a rate that is sufficient for successful deconvolution. The Richardson-Lucy deconvolution algorithm is used to obtain an increase in resolution of a factor of about 2 or 3 from the normal IRAS detector sizes of 45, 45, 90, and 180 arcsec at wavelengths 12, 25, 60, and 100 microns. Most of the planetaries deconvolve at 12 and 25 microns to sizes equal to or smaller than the optical size. Some of the planetaries with optical rings 60 arcsec or more in diameter show double-peaked IRAS profiles. Many, such as NGC 6720 and NGC 6543 show all infrared sizes equal to the optical size, while others indicate increasing infrared size with wavelength. Deconvolved IRAS profiles are presented for the 57 planetaries at nearly all wavelengths where IRAS flux densities are 1-2 Jy or higher. 60 refs.

  13. Detailed atmosphere calculations of accretion disks around intermediate mass black holes, and their application to observations of ultra-luminous X-ray sources

    NASA Astrophysics Data System (ADS)

    Hui, Yawei

    2009-01-01

    We have calculated the structures and the emergent spectra of stationary, geometrically thin accretion disks around intermediate mass black holes (IMBH) in both the Schwarzschild and extreme Kerr metrics. Equations of radiative transfer, hydrostatic equilibrium, energy balance, ionization equilibrium, and statistical equilibrium are solved simultaneously and consistently. The six most astrophysically abundant elements (H, He, C, N, O, and Fe) are included, as well as energy transfer by Comptonization. The observed spectrum as a function of viewing angle is computed, incorporating all general relativistic effects. We find that, in contrast with the predictions of the commonly used multicolor disk (MCD) model, opacity associated with photoionization of heavy elements can significantly alter the spectrum near its peak. These ionization edges can create spectral breaks visible in the spectra of slowly spinning black holes viewed from almost all angles and in the spectra of rapidly spinning black holes seen approximately face-on. For fixed mass and accretion rate relative to Eddington, both the black hole spin and the viewing angle can significantly shift the observed peak energy of the spectrum, particularly for rapid spin viewed edge-on. We present a detailed test of the approximations made in various forms of the MCD model. Linear limb-darkening is confirmed to be a reasonable approximation for the integrated flux but not for many specific frequencies of interest. To test if our atmosphere calculation would shed a new light in modeling observations of Ultra-Luminous X-ray sources (ULX) in which many researchers believe to harbor IMBHs, we have chosen 6 ULXs from the XMM-Newton archive whose spectra have high signal-to-noise and can be fitted solely with a disk model without requiring any power-law component. To estimate systematic errors in the inferred parameters, we fit every spectrum to two different disk models, one based on local blackbody emission (KERRBB) and

  14. Molecular jet of IRAS 04166+2706

    SciTech Connect

    Wang, Liang-Yao; Shang, Hsien; Su, Yu-Nung; Hirano, Naomi; Lee, Chin-Fei; Santiago-García, Joaquín; Tafalla, Mario; Zhang, Qizhou

    2014-01-01

    The molecular outflow from IRAS 04166+2706 was mapped with the Submillimeter Array at a 350 GHz continuum and CO J = 3-2 at an angular resolution of ∼1''. The field of view covers the central arcminute, which contains the inner four pairs of knots of the molecular jet. On the channel map, conical structures are clearly present in the low-velocity range (|V – V {sub 0}| < 10 km s{sup –1}), and the highly collimated knots appear in the extremely high velocity range (50 >|V – V {sub 0}| > 30 km s{sup –1}). The higher angular resolution of ∼1'' reveals the first blue-shifted knot (B1) that was missing in previous Plateau de Bure Interferometer observation of Santiago-García et al. at an offset of ∼6'' to the northeast of the central source. This identification completes the symmetric sequence of knots in both the blue- and red-shifted lobes of the outflow. The innermost knots R1 and B1 have the highest velocities within the sequence. Although the general features appear to be similar to previous CO J = 2-1 images in Santiago-García et al., the emission in CO J = 3-2 almost always peaks further away from the central source than that of CO J = 2-1 in the red-shifted lobe of the channel maps. This gives rise to a gradient in the line-ratio map of CO J = 3-2/J = 2-1 from head to tail within a knot. A large velocity gradient analysis suggests that the differences may reflect a higher gas kinetic temperature at the head. We also explore possible constraints imposed by the nondetection of SiO J = 8-7.

  15. Molecular Jet of IRAS 04166+2706

    NASA Astrophysics Data System (ADS)

    Wang, Liang-Yao; Shang, Hsien; Su, Yu-Nung; Santiago-García, Joaquín; Tafalla, Mario; Zhang, Qizhou; Hirano, Naomi; Lee, Chin-Fei

    2014-01-01

    The molecular outflow from IRAS 04166+2706 was mapped with the Submillimeter Array at a 350 GHz continuum and CO J = 3-2 at an angular resolution of ~1''. The field of view covers the central arcminute, which contains the inner four pairs of knots of the molecular jet. On the channel map, conical structures are clearly present in the low-velocity range (|V - V 0| < 10 km s-1), and the highly collimated knots appear in the extremely high velocity range (50 >|V - V 0| > 30 km s-1). The higher angular resolution of ~1'' reveals the first blue-shifted knot (B1) that was missing in previous Plateau de Bure Interferometer observation of Santiago-García et al. at an offset of ~6'' to the northeast of the central source. This identification completes the symmetric sequence of knots in both the blue- and red-shifted lobes of the outflow. The innermost knots R1 and B1 have the highest velocities within the sequence. Although the general features appear to be similar to previous CO J = 2-1 images in Santiago-García et al., the emission in CO J = 3-2 almost always peaks further away from the central source than that of CO J = 2-1 in the red-shifted lobe of the channel maps. This gives rise to a gradient in the line-ratio map of CO J = 3-2/J = 2-1 from head to tail within a knot. A large velocity gradient analysis suggests that the differences may reflect a higher gas kinetic temperature at the head. We also explore possible constraints imposed by the nondetection of SiO J = 8-7.

  16. CARBON STARS WITH INFRARED SPECTRA IN GROUP P OF THE IRAS/LRS DATABASE

    SciTech Connect

    Chen, P. S.

    2012-10-01

    Sources with infrared spectra in Group P of the IRAS/LRS database all show polycyclic aromatic hydrocarbon features. They are often planetary nebulae, H II regions, reflection/dark nebulae, Wolf-Rayet stars, or external galaxies. However, we noted that some carbon stars are also included in this group. We searched for and investigated all infrared spectra in Group P of the IRAS/LRS database. Finally, we found 11 previously known carbon stars and identified 8 new candidate carbon stars in Group P. Infrared spectra of these stars may present the 11.2 {mu}m SiC emission features indicative of their carbon-rich properties.

  17. IRAS variables as galactic structure tracers - Classification of the bright variables

    NASA Technical Reports Server (NTRS)

    Allen, L. E.; Kleinmann, S. G.; Weinberg, M. D.

    1993-01-01

    The characteristics of the 'bright infrared variables' (BIRVs), a sample consisting of the 300 brightest stars in the IRAS Point Source Catalog with IRAS variability index VAR of 98 or greater, are investigated with the purpose of establishing which of IRAS variables are AGB stars (e.g., oxygen-rich Miras and carbon stars, as was assumed by Weinberg (1992)). Results of the analysis of optical, infrared, and microwave spectroscopy of these stars indicate that, out of 88 stars in the BIRV sample identified with cataloged variables, 86 can be classified as Miras. Results of a similar analysis performed for a color-selected sample of stars, using the color limits employed by Habing (1988) to select AGB stars, showed that, out of 52 percent of classified stars, 38 percent are non-AGB stars, including H II regions, planetary nebulae, supergiants, and young stellar objects, indicating that studies using color-selected samples are subject to misinterpretation.

  18. Specification of IRAS confused regions. Rept. for 11 Jan-11 May 90

    SciTech Connect

    Kennealy, J.P.; Woodward, C.E.; Korte, R.M.

    1990-06-19

    This document reports on the efforts to define the IRAS confused regions. The subset will be limited by the availability of survey data in the regions which are identified as point source confused by the current (Ver 2.0) IRAS point source catalog (PSC). Available coincident AO data will be an important validation source. The sensitivity and spatial resolution capabilities of the IRAS telescope failed to resolve individual sources in many regions of high source density. Approximately 10% of the sources catalogued in the PSC are tagged as 'confused' in some way; the location of a source, the number of sources at a location, the temporal occurrence and variation of a source, and/or the intensity of a source(s) was not discernible by the source identification/discrimination methods used to compile the PSC. In these regions of infrared clutter, the PSC can underestimate the number of point sources by as much as a factor of 3 to 5 in the IRAS Bands 1 and 2 (12 and 25 micrometers respectively). Analysis for improved source counts is designed to enhance the description and spatial definition of the mid- and long wavelength infrared celestial background, and includes generation of high spatial resolution images of the confused regions. Analysis of these images will improve the accuracy of source counts, locations, and flux estimates in the PSC. More detailed knowledge of the high source density regions will improve our ability to understand star formation and galactic evolution. It will also greatly improve our knowledge of a type of celestial background which presents a serious clutter problem for space-born surveillance system sensors.

  19. The young stellar cluster associated with IRAS 09149-4743

    NASA Astrophysics Data System (ADS)

    Ortiz, R.; Roman-Lopes, A.; Abraham, Z.

    2007-01-01

    Context: We present the results of a near-infrared survey of the young stellar cluster associated with IRAS 09149-4743, a member of the Vela Molecular Ridge. Aims: The main purpose of this survey is to study the cluster members and find the ionizing sources of the associated HII region. Methods: Infrared photometry of 62 stars located in the crowded parts of the cluster is given in the J, H, and K bands. Colour-colour and colour-magnitude diagrams are drawn to obtain an estimate of their spectral type and reddening. Results: Three main sources are identified as candidates to ionize the HII region: a star located at the centre of the cluster, inside the IRAS error ellipse; a second star, member of a small "subcluster" situated 1.1' to the southeast of the former; and a third object, showing very high colour indices, which indicate visual extinction over 20 mag. Dereddened J magnitudes suggest that the former two stars probably are the main ionizing sources, whereas the latter is too reddened to allow a reliable estimate of its spectral type by photometric methods.

  20. High spatial resolution restoration of IRAS images

    NASA Technical Reports Server (NTRS)

    Grasdalen, Gary L.; Inguva, R.; Dyck, H. Melvin; Canterna, R.; Hackwell, John A.

    1990-01-01

    A general technique to improve the spatial resolution of the IRAS AO data was developed at The Aerospace Corporation using the Maximum Entropy algorithm of Skilling and Gull. The technique has been applied to a variety of fields and several individual AO MACROS. With this general technique, resolutions of 15 arcsec were achieved in 12 and 25 micron images and 30 arcsec in 60 and 100 micron images. Results on galactic plane fields show that both photometric and positional accuracy achieved in the general IRAS survey are also achieved in the reconstructed images.

  1. What are IRAS galaxies? an optical answer

    NASA Astrophysics Data System (ADS)

    Meadows, V. S.; Allen, D. A.; Norris, R. P.; Roche, P. F.

    A survey of the optical spectra of IRAS galaxies, made with the AAT, has shown that the majority have strong emission lines. Ratios of the emission lines have been plotted on the Veilleux-Osterbrock diagram (forbidden O III/H-beta against forbidden N II/H-alpha); this shows that the IRAS galaxies comprise several classes. In this sample, the majority appear to be starburst galaxies, but Seyfert, Liner, and narrow-line galaxies are also represented. Coadded spectra of the galaxy classes are presented. On the basis of optical spectroscopy, it appears that the starburst phenomenon is capable of generating luminosities exceeding 10 to the 12th solar luminosities.

  2. From IRAS Excesses to Debris Disks

    NASA Astrophysics Data System (ADS)

    Backman, D.; Lagrange, A.-M.

    2014-09-01

    Noted only as a shell star prior to 1984, beta Pictoris was originally observed in the first months of the IRAS mission as a comparison object for Vega. When Fred Gillett presented spectral energy distributions of Vega, Fomalhaut, beta Pictoris, and epsilon Eridani at the Protostars and Planets II conference, the news was relayed quickly to Brad Smith and Rich Terrile who were observing at Las Campanas with a coronagraph. Our understanding that beta Pictoris and other debris disks are clear evidence of maturing planetary systems solidified over the following 15 years with analyses of IRAS & ISO data coupled with spectroscopic observations of Falling Evaporating Bodies.

  3. VizieR Online Data Catalog: JHK photometry around IRAS 09149-4743 (Ortiz+, 2007)

    NASA Astrophysics Data System (ADS)

    Ortiz, R.; Roman-Lopes, A.; Abraham, Z.

    2006-10-01

    Table 2 contains positions and JHK photometry of a set of infrared sources, situated in two crowded areas of the stellar cluster associated with IRAS 09149-4743. All measurements were carried out with the infrared camera "CamIV", as described in Sect. 3 of the paper. (1 data file).

  4. IRAS observations of a large sample of normal irregular galaxies

    NASA Technical Reports Server (NTRS)

    Hunter, Deidre A.; Gallagher, John S., III; Rice, Walter L.; Gillett, Fred C.

    1989-01-01

    IRAS 12, 25, 60, and 100 micron data are presented for a sample of Irr galaxies which span a large range in star-formation activity. It is found that the dwarf, giant, and amorphous Irr's generally have similar IR properties. The typical L(IR)/L(H-alpha) ratios of most classes of Irr's, except for many of the luminous blue galaxies, are low compared with those of spiral galaxies and are consistent with the Irr's being relatively transparent systems without large amounts of optically hidden star formation. Compared with spiral galaxies, the Irr's have similar L(IR)/L(B) ratios, warmer S(100)/S(60) ratios, cooler S(25)/S(12) ratios, and lower dust-to-H I gas mass ratios. The temperature, dust-to-H I gas mass ratios, and L(IR)/L(B) ratios do not correlate with the metallicity of the ionized gas of the Irr's. A correlation between the IR fluxes and both the H-alpha and the blue stellar fluxes is found for the Irr's.

  5. THE TOTAL LUMINOUS EFFICIENCY OF LUMINOUS BACTERIA.

    PubMed

    Harvey, E N

    1925-09-18

    Methods are described for measuring the light emitted by an emulsion of luminous bacteria of given thickness, and calculating the light emitted by a single bacterium, measuring 1.1 x 2.2 micra, provided there is no absorption of light in the emulsion. At the same time, the oxygen consumed by a single bacterium was measured by recording the time for the bacteria to use up .9 of the oxygen dissolved in sea water from air (20 per cent oxygen). The luminescence intensity does not diminish until the oxygen concentration falls below 2 per cent, when the luminescence diminishes rapidly. Above 2 per cent oxygen (when the oxygen dissolving in sea water from pure oxygen at 760 mm. Hg pressure = 100 per cent) the bacteria use equal amounts of oxygen in equal times, while below 2 per cent oxygen it seems very likely that rate of oxygen absorption is proportional to oxygen concentration. By measuring the time for a tube of luminous bacteria of known concentration saturated with air (20 per cent oxygen) to begin to darken (2 per cent oxygen) we can calculate the oxygen absorbed by one bacterium per second. The bacteria per cc. are counted on a blood counting slide or by a centrifugal method, after measuring the volume of a single bacterium (1.695 x 10(-12) cc.). Both methods gave results in good agreement with each other. The maximum value for the light from a single bacterium was 24 x 10(-14) lumens or 1.9 x 10(-14) candles. The maximum value for lumen-seconds per mg. of oxygen absorbed was 14. The average value for lumen-seconds per mg. O(2) was 9.25. The maximum values were selected in calculating the efficiency of light production, since some of the bacteria counted may not be producing light, although they may still be using oxygen. The "diet" of the bacteria was 60 per cent glycerol and 40 per cent peptone. To oxidize this mixture each mg. of oxygen would yield 3.38 gm. calories or 14.1 watts per second. 1 lumen per watt is therefore produced by a normal bacterium which

  6. The Most Luminous Object in the Universe: Shrouded Quasar or Proto-Galaxy

    NASA Technical Reports Server (NTRS)

    Heckman, Timothy M.

    1999-01-01

    We have used ASCA to observe the IRAS source FSC 10214+4724, which is identified with a galaxy at a redshift of 2.286. When first discovered, it was believed to be the most luminous object in the universe. Subsequent HST images have established that it is gravitationally-lensed by a foreground cluster. It is still a very powerful object, but not extraordinarily so. Observations at other wavebands have not established whether it is a dust-shrouded quasar or a young, massive galaxy in the process of formation. Since quasars are strong emitters of hard X-rays, while proto-galaxies would not be, and since the opacity of gas and dust is relatively small in the energy regime probed by ASCA (3 to 30 keV in the galaxy rest frame), we undertook these observations to search for a heavily shrouded quasar that might be invisible at lower energies. However, the observations did not detect any emission from this object. This either means that the galaxy is in fact powered by a starburst or that the putative quasar is located behind a very high column density of absorbing gas (N_H > 10(exp 25)/sq cm), so that not even hard X-rays are transmitted. A hidden quasar should be visible in reflected light in X-ray data of higher sensitivity. Observations with NASA's Chandra X-ray Observatory or ESA's XMM are required to settle the matter. No publication resulted from our null result.

  7. IRAS and the Boston University Arecibo Galactic H I Survey: A catalog of cloud properties

    NASA Technical Reports Server (NTRS)

    Bania, Thomas M.

    1992-01-01

    The Infrared Astronomy Satellite (IRAS) Galactic Plane Surface Brightness Images were used to identify infrared emission associated with cool, diffuse H I clouds detected by the Boston University-Arecibo Galactic H I Survey. These clouds are associated with galactic star clusters, H II regions, and molecular clouds. Using emission-absorption experiments toward galactic H II regions, we determined the H I properties of cool H I clouds seen in absorption against the thermal continuum, including their kinematic distances. Correlations were then made between IRAS sources and these H II regions, thus some of the spatial confusion associated with the IRAS fields near the galactic plane was resolved since the distances to these sources was known. Because we can also correlate the BU-Arecibo clouds with existing CO surveys, these results will allow us to determine the intrinsic properties of the gas (neutral and ionized atomic as well as molecular) and dust for interstellar clouds in the inner galaxy. For the IRAS-identified H II region sample, we have established the far infrared (FIR) luminosities and galactic distribution of these sources.

  8. A redshift survey of IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Smith, Beverly J.; Kleinmann, S. G.; Huchra, J. P.; Low, F. J.

    1987-01-01

    Results are presented from a redshift survey of all 72 galaxies detected by IRAS in Band 3 at flux levels equal to or greater then 2 Jy. The luminosity function at the high luminosity end is proportional to L sup -2, however, a flattening was observed at the low luminosity end indicating that a single power law is not a good description of the entire luminosity function. Only three galaxies in the sample have emission line spectra indicative of AGN's, suggesting that, at least in nearby galaxies, unobscured nuclear activity is not a strong contributor to the far infrared flux. Comparisons between the selected IRAS galaxies and an optically complete sample taken from the CfA redshift survey show that they are more narrowly distributed than those optically selected, in the sence that the IRAS sample includes few galaxies of low absolute blue luminosity. It was also found that the space distributions of the two samples differ: the density enhancement or IRAS galaxies is only approx. 1/3 that of the optically selected galaxies in the core of the Coma cluster.

  9. CRYSTALLINE SILICATES IN EVOLVED STARS. I. SPITZER/INFRARED SPECTROGRAPH SPECTROSCOPY OF IRAS 16456-3542, 18354-0638, AND 23239+5754

    SciTech Connect

    Jiang, B. W.; Zhang, Ke; Li, Aigen; Lisse, C. M. E-mail: kzhang@caltech.edu E-mail: carey.lisse@jhuapl.edu

    2013-03-01

    We report the Spitzer Infrared Spectrograph (IRS) observations of three evolved stars: IRAS 16456-3542, 18354-0638, and 23239+5754. The 9.9-37.2 {mu}m Spitzer/IRS high-resolution spectra of these three sources exhibit rich sets of enstatite-dominated crystalline silicate emission features. IRAS 16456-3542 is extremely rich in crystalline silicates, with >90% of its silicate mass in crystalline form, the highest to date ever reported for crystalline silicate sources.

  10. AN EMBEDDED ACTIVE NUCLEUS IN THE OH MEGAMASER GALAXY IRAS16399–0937

    SciTech Connect

    Sales, Dinalva A.; Robinson, A.; Axon, D. J.; Curran, R. L.; O'Dea, C.; Mittal, R.; Gallimore, J.; Kharb, P.; Baum, S.; Elitzur, M.

    2015-01-20

    We present a multiwavelength study of the OH megamaser galaxy IRAS16399–0937, based on new Hubble Space Telescope (HST)/Advanced Camera for Surveys F814W and Hα+[N II] images and archive data from HST, Two Micron All Sky Survey, Spitzer, Herschel and the Very Large Array. This system has a double nucleus, whose northern (IRAS16399N) and southern (IRAS16399S) components have a projected separation of ∼6'' (3.4 kpc) and have previously been identified based on optical spectra as a low ionization nuclear emission line region (LINER) and starburst nucleus, respectively. The nuclei are embedded in a tidally distorted common envelope, in which star formation is mostly heavily obscured. The infrared spectrum is dominated by strong polycyclic aromatic hydrocarbon, but deep silicate and molecular absorption features are also present, and are strongest in the IRAS16399N nucleus. The 0.435-500 μm spectral energy distribution was fitted with a model including stellar, interstellar medium and active galactic nucleus (AGN) torus components using our new Markov Chain Monte Carlo code, CLUMPYDREAM. The results indicate that the IRAS16399N contains an AGN (L {sub bol} ∼ 10{sup 44} erg s{sup –1}) deeply embedded in a quasi-spherical distribution of optically thick clumps with a covering fraction ≈1. We suggest that these clumps are the source of the OHM emission in IRAS16399–0937. The high torus covering fraction precludes AGN photoionization as the origin of the LINER spectrum, however, the spectrum is consistent with shocks (v ∼ 100-200 km s{sup –1}). We infer that the ∼10{sup 8} M {sub ☉} black hole in IRAS16399N is accreting at a small fraction (∼1%) of its Eddington rate. The low accretion rate and modest nuclear star formation rates suggest that while the gas-rich major merger forming the IRAS16399–0937 system has triggered widespread star formation, the massive gas inflows expected from merger simulations have not yet fully developed.

  11. An Embedded Active Nucleus in the OH Megamaser Galaxy IRAS16399-0937

    NASA Astrophysics Data System (ADS)

    Sales, Dinalva A.; Robinson, A.; Axon, D. J.; Gallimore, J.; Kharb, P.; Curran, R. L.; O'Dea, C.; Baum, S.; Elitzur, M.; Mittal, R.

    2015-01-01

    We present a multiwavelength study of the OH megamaser galaxy IRAS16399-0937, based on new Hubble Space Telescope (HST)/Advanced Camera for Surveys F814W and Hα+[N II] images and archive data from HST, Two Micron All Sky Survey, Spitzer, Herschel and the Very Large Array. This system has a double nucleus, whose northern (IRAS16399N) and southern (IRAS16399S) components have a projected separation of ~6'' (3.4 kpc) and have previously been identified based on optical spectra as a low ionization nuclear emission line region (LINER) and starburst nucleus, respectively. The nuclei are embedded in a tidally distorted common envelope, in which star formation is mostly heavily obscured. The infrared spectrum is dominated by strong polycyclic aromatic hydrocarbon, but deep silicate and molecular absorption features are also present, and are strongest in the IRAS16399N nucleus. The 0.435-500 μm spectral energy distribution was fitted with a model including stellar, interstellar medium and active galactic nucleus (AGN) torus components using our new Markov Chain Monte Carlo code, CLUMPYDREAM. The results indicate that the IRAS16399N contains an AGN (L bol ~ 1044 erg s-1) deeply embedded in a quasi-spherical distribution of optically thick clumps with a covering fraction ≈1. We suggest that these clumps are the source of the OHM emission in IRAS16399-0937. The high torus covering fraction precludes AGN photoionization as the origin of the LINER spectrum, however, the spectrum is consistent with shocks (v ~ 100-200 km s-1). We infer that the ~108 M ⊙ black hole in IRAS16399N is accreting at a small fraction (~1%) of its Eddington rate. The low accretion rate and modest nuclear star formation rates suggest that while the gas-rich major merger forming the IRAS16399-0937 system has triggered widespread star formation, the massive gas inflows expected from merger simulations have not yet fully developed. Based partly on observations made with the NASA/ESA Hubble Space

  12. OUTFLOWS AND MASSIVE STARS IN THE PROTOCLUSTER IRAS 05358+3543

    SciTech Connect

    Ginsburg, Adam G.; Bally, John; Yan Chihung; Williams, Jonathan P. E-mail: John.Bally@colorado.ed

    2009-12-10

    We present new near-IR H{sub 2}, CO J = 2-1, and CO J = 3-2 observations to study outflows in the massive star-forming region IRAS 05358+3543. The Canada-France-Hawaii Telescope H{sub 2} images and James Clerk Maxwell Telescope CO data cubes of the IRAS 05358 region reveal several new outflows, most of which emerge from the dense cluster of submillimeter cores associated with the Sh 2-233IR NE cluster to the northeast of IRAS 05358. We used Apache Point Observatory JHK spectra to determine line-of-sight velocities of the outflowing material. Analysis of archival Very Large Array cm continuum data and previously published very long baseline interferometry observations reveal a massive star binary as a probable source of one or two of the outflows. We have identified probable sources for six outflows and candidate counterflows for seven out of a total of 11 seen to be originating from the IRAS 05358 clusters. We classify the clumps within Sh 2-233IR NE as an early protocluster and Sh 2-233IR SW as a young cluster, and conclude that the outflow energy injection rate approximately matches the turbulent decay rate in Sh 2-233IR NE.

  13. An assessment of image reconstruction from balloon-borne and the IRAS data

    NASA Technical Reports Server (NTRS)

    Ghosh, S. K.; Das, B.; Rengarajan, T. N.; Verma, R. P.

    1994-01-01

    Angular resolution and structural information from the far-infrared mapping of astronomical sources (Galactic star forming regions, spiral galaxies, etc.) made using the TIFR 1 m balloon-borne telescope and the IRAS have been compared. The effective wavelengths of the TIFR two-band photometer are 58 and 150 microns. From IRAS, the survey COADD data, additional observations (AO's) made with the survey detectors with different Macros (DPS, DSD, DPM), as well as the chopped photometric channel (CPC) data have been considered here. The observed signals have been processed using different deconvolution strategies, either based on a maximum entropy method (MEM) developed at TIFR or the HiRes package developed at IPAC. Relative merits of each of these, under different conditions of signal to noise ratio, are highlighted. The following sources have been selected for illustration: Carina complex, W31 region, IRAS 10361-5830 (all Galactic), M101 and M81 (extragalactic). The main conclusions are: far-infrared maps from MEM deconvolution of balloon-borne data have the best angular resolution; MEM deconvolution of IRAS AO's gives resolution comparable to HiRes but with less amount of computation, though the dynamic range in MEM maps is less than in HiRes maps.

  14. Study of the Byurakan-IRAS galaxy sample

    NASA Astrophysics Data System (ADS)

    Mickaelian, Areg M.; Harutyunyan, Gohar S.

    2013-03-01

    The Byurakan-IRAS Galaxy (BIG) sample (Mickaelian 1995) is the result of optical identifications of IRAS PSC sources at high-galactic latitudes using the First Byurakan Survey (FBS) low-dispersion spectra (Markarian et al. 1989). Among the 1577 objects 1178 galaxies have been identified. Most are dusty spiral galaxies and there are a number of ULIRGs among these objects. Our spectroscopic observations carried out with three telescopes (Byurakan Astrophysical Observatory 2.6m, Russian Special Astrophysical Observatory 6m and Observatoire de Haute Provence 1.93m) (Mickaelian & Sargsyan 2010) for 172 galaxies, as well as the SDSS DR8 spectra for 83 galaxies make up the list of 255 spectroscopically studied BIG objects. The classification to activity types for narrow-line emission galaxies has been carried out using the diagnostic diagrams by Veilleux & Osterbrock (1987). All possible physical characteristics have been measured and/or calculated, including radial velocities and distances, angular and physical sizes, absolute magnitudes and luminosities (both optical and IR). IR luminosities and star-formation rates have been calculated from the IR fluxes (Duc et al. 1997).

  15. Molecular gas associated with IRAS 10361-5830

    NASA Astrophysics Data System (ADS)

    Vazzano, M. M.; Cappa, C. E.; Vasquez, J.; Rubio, M.; Romero, G. A.

    2014-10-01

    Aims: We analyze the distribution of the molecular gas and dust in the molecular clump linked to IRAS 10361-5830, located in the environs of the bubble-shaped Hii region Gum 31 in the Carina region, with the aim of determining the main parameters of the associated material and of investigating the evolutionary state of the young stellar objects identified there. Methods: Using the APEX telescope, we mapped the molecular emission in the J = 3-2 transition of three CO isotopologues, 12CO, 13CO and C18O, over a 1.´5 × 1.´5 region around the IRAS position. We also observed the high-density tracers CS and HCO+ toward the source. The cold- dust distribution was analyzed using submillimeter continuum data at 870 μm obtained with the APEX telescope. Complementary IR and radio data at different wavelengths were used to complete the study of the interstellar medium. Results: The molecular gas distribution reveals a cavity and a shell-like structure of ~0.32 pc in radius centered at the position of the IRAS source, with some young stellar objects projected onto the cavity. The total molecular mass in the shell and the mean H2volume density are ~40 M⊙ and ~(1-2) × 103 cm-3. The cold-dust counterpart of the molecular shell has been detected in the far-IR at 870 μm and in Herschel data at 350 μm. Weak extended emission at 24 μm from warm dust is projected onto the cavity, as well as weak radio continuum emission. Conclusions: A comparison of the distribution of cold and warm dust, and molecular and ionized gas allows us to conclude that a compact Hii region has developed in the molecular clump, indicating that this is an area of recent massive star formation. Probable exciting sources capable of creating the compact Hii region are investigated. The 2MASS source 10380461-5846233 (MSX G286.3773-00.2563) seems to be responsible for the formation of the Hii region. FITS files with datacubes corresponding to 12CO, 13CO, C180 maps are only available at the CDS via anonymous

  16. The VLA Nascent Disk and Multiplicity (VANDAM) Survey of Perseus Protostars. Resolving the Sub-arcsecond Binary System in NGC 1333 IRAS2A

    NASA Astrophysics Data System (ADS)

    Tobin, John J.; Dunham, Michael M.; Looney, Leslie W.; Li, Zhi-Yun; Chandler, Claire J.; Segura-Cox, Dominique; Sadavoy, Sarah I.; Melis, Carl; Harris, Robert J.; Perez, Laura M.; Kratter, Kaitlin; Jørgensen, Jes K.; Plunkett, Adele L.; Hull, Charles L. H.

    2015-01-01

    We are conducting a Jansky Very Large Array (VLA) Ka-band (8 mm and 1 cm) and C-band (4 cm and 6.4 cm) survey of all known protostars in the Perseus Molecular Cloud, providing resolution down to ~0.''06 and ~0.''35 in the Ka band and C band, respectively. Here we present first results from this survey that enable us to examine the source NGC 1333 IRAS2A in unprecedented detail and resolve it into a protobinary system separated by 0.''621 ± 0.''006 (~143 AU) at 8 mm, 1 cm, and 4 cm. These two sources (IRAS2A VLA1 and VLA2) are likely driving the two orthogonal outflows known to originate from IRAS2A. The brighter source IRAS2A VLA1 is extended perpendicular to its outflow in the VLA data, with a deconvolved size of 0.''055 (~13 AU), possibly tracing a protostellar disk. The recently reported candidate companions (IRAS2A MM2 and MM3) are not detected in either our VLA data, Combined Array for Research in Millimeter-wave Astronomy (CARMA) 1.3 mm data, or Submillimeter Array (SMA) 850 μm data. SMA CO (J = 3 → 2), CARMA CO (J = 2 → 1), and lower-resolution CARMA CO (J = 1 → 0) observations are used to examine the outflow origins and the nature of the candidate companions to IRAS2A VLA1. The CO (J = 3 → 2) and (J = 2 → 1) data show that IRAS2A MM2 is coincident with a bright CO emission spot in the east-west outflow, and IRAS2A MM3 is within the north-south outflow. In contrast, IRAS2A VLA2 lies at the east-west outflow symmetry point. We propose that IRAS2A VLA2 is the driving source of the east-west outflow and a true companion to IRAS2A VLA1, whereas IRAS2A MM2 and MM3 may not be protostellar.

  17. THE VLA NASCENT DISK AND MULTIPLICITY (VANDAM) SURVEY OF PERSEUS PROTOSTARS. RESOLVING THE SUB-ARCSECOND BINARY SYSTEM IN NGC 1333 IRAS2A

    SciTech Connect

    Tobin, John J.; Looney, Leslie W.; Dunham, Michael M.; Li, Zhi-Yun; Chandler, Claire J.; Perez, Laura M.; Segura-Cox, Dominique; Harris, Robert J.; Hull, Charles L. H.; Sadavoy, Sarah I.; Melis, Carl; Kratter, Kaitlin; Jørgensen, Jes K.; Plunkett, Adele L. E-mail: jeskj@nbi.dk

    2015-01-01

    We are conducting a Jansky Very Large Array (VLA) Ka-band (8 mm and 1 cm) and C-band (4 cm and 6.4 cm) survey of all known protostars in the Perseus Molecular Cloud, providing resolution down to ∼0.''06 and ∼0.''35 in the Ka band and C band, respectively. Here we present first results from this survey that enable us to examine the source NGC 1333 IRAS2A in unprecedented detail and resolve it into a protobinary system separated by 0.''621 ± 0.''006 (∼143 AU) at 8 mm, 1 cm, and 4 cm. These two sources (IRAS2A VLA1 and VLA2) are likely driving the two orthogonal outflows known to originate from IRAS2A. The brighter source IRAS2A VLA1 is extended perpendicular to its outflow in the VLA data, with a deconvolved size of 0.''055 (∼13 AU), possibly tracing a protostellar disk. The recently reported candidate companions (IRAS2A MM2 and MM3) are not detected in either our VLA data, Combined Array for Research in Millimeter-wave Astronomy (CARMA) 1.3 mm data, or Submillimeter Array (SMA) 850 μm data. SMA CO (J = 3 → 2), CARMA CO (J = 2 → 1), and lower-resolution CARMA CO (J = 1 → 0) observations are used to examine the outflow origins and the nature of the candidate companions to IRAS2A VLA1. The CO (J = 3 → 2) and (J = 2 → 1) data show that IRAS2A MM2 is coincident with a bright CO emission spot in the east-west outflow, and IRAS2A MM3 is within the north-south outflow. In contrast, IRAS2A VLA2 lies at the east-west outflow symmetry point. We propose that IRAS2A VLA2 is the driving source of the east-west outflow and a true companion to IRAS2A VLA1, whereas IRAS2A MM2 and MM3 may not be protostellar.

  18. Evaluation of expanded uncertainties in luminous intensity and illuminance calibrations

    SciTech Connect

    Sametoglu, Ferhat

    2008-11-01

    Detector-based calibrating methods and expressions for calculation of photometric uncertainties related to uncertainties in the calibrations of luminous intensity of a light source, illuminance responsivity of a photometer head, and calibration factors of an illuminance meter are discussed. These methods permit luminous intensity calibrations of incandescent light sources, luminous responsivity calibrations of photometer heads, and calibration factors of illuminance meters to be carried out with relative expanded uncertainties (with a level of confidence of 95.45%) of 0.4%, 0.4%, and 0.6%, respectively.

  19. Accretion disks in the IRAS 23151+5912 region

    SciTech Connect

    Rodríguez-Esnard, T.; Trinidad, M. A.; Migenes, V. E-mail: trinidad@astro.ugto.mx

    2014-06-20

    We present observations of radio continuum emission at 1.3 and 3.6 cm and H{sub 2}O masers toward the high-mass star-forming region IRAS 23151+5912 carried out with the Very Large Array-Expanded Very Large Array (in transition phase) in configuration A. We detected one continuum source at 1.3 cm in the region, but the counterpart of this radio continuum source at 3.6 cm was not detected at a level of 3σ. We also detected 13 water maser spots toward IRAS 23151+5912, which are distributed in three groups aligned along the northeast-southwest direction. Our results suggest that the 1.3 cm emission is consistent with a hypercompact H II region, probably with an embedded zero-age main-sequence star of type B2. In particular, we find that this young star is spatially associated with a maser group, which is tracing a disk-like structure of about 460 AU. We also find that the masers of the second group are probably describing a circumstellar disk of about 86 AU, whose central protostar, still undetected, should have a mass of ∼11 M {sub ☉}. We also suggest that the third water maser group is possibly associated with the SiO outflow and the undetected driving source of the system. Finally, we noted that the 1.3 cm continuum source and the three maser groups are aligned in the northeast-southwest direction, similar to the elongation of the large ionized region, which probably is the result of shock-wave induced star formation on the densest region of the medium.

  20. Erratum: IRAS observations of irregular galaxies

    NASA Technical Reports Server (NTRS)

    Hunter, D. A.; Gallagher, J. S.

    1987-01-01

    In Infrared Astronomy Satellite (IRAS) observations of irregular galaxies, galactic blue luminosities were based on standard optical definitions. The blue luminosities (L sub B) were derived from the blue absolute magnitude (M sub B) or form the in band flux. However, the L sub B system for spiral galaxies was based on quasi-bolometric (rather than in band) fluxes. The formulation and resulting statements are corrected.

  1. Wide Field CO Mapping in the Region of IRAS 19312+1950

    NASA Astrophysics Data System (ADS)

    Nakashima, Jun-ichi; Ladeyschikov, Dmitry A.; Sobolev, Andrej M.; Zhang, Yong; Hsia, Chih-Hao; Yung, Bosco H. K.

    2016-07-01

    We report the results of wide field CO mapping in the region of IRAS 19312+1950. This Infrared Astronomical Satellite (IRAS) object exhibits SiO/H2O/OH maser emission, and is embedded in a chemically rich molecular component, the origin of which is still unknown. In order to reveal the entire structure and gas mass of the surrounding molecular component for the first time, we have mapped a wide region around IRAS 19312+1950 in the 12CO J = 1–0, 13CO J = 1–0 and C18O J = 1–0 lines using the Nobeyama 45 m telescope. In conjunction with archival CO maps, we investigated a region up to 20‧ × 20‧ in size around this IRAS object. We calculated the CO gas mass assuming local thermal equilibrium, the stellar velocity through the interstellar medium assuming an analytic model of bow shock, and the absolute luminosity, using the latest archival data and trigonometric parallax distance. The derived gas mass (225 M ⊙–478 M ⊙) of the molecular component and the relatively large luminosity (2.63 × 104 L ⊙) suggest that the central SiO/H2O/OH maser source is a red supergiant rather than an asymptotic giant branch (AGB) star or post-AGB star.

  2. VizieR Online Data Catalog: VLA & Chandra obs. of IRAS20126+4104 region (Montes+, 2015)

    NASA Astrophysics Data System (ADS)

    Montes, V. A.; Hofner, P.; Anderson, C.; Rosero, V.

    2015-11-01

    We observed the IRAS 20126+4104 region with the Chandra ACIS-I instrument on 2003 March 17 for a total exposure time of 39.35ks. C-band (6cm) continuum observations of the massive star-forming region IRAS 20126+4104 were conducted with the VLA operated by NRAO on 2011 August 7. These data are augmented by NIR and optical archival data. We identify 150 X-ray sources, 88 of which have NIR counterparts. For the Mid-IR wavelength regions we searched the Spitzer Enhanced Imaging Products Point Source catalog. (3 data files).

  3. IRAS sky survey atlas: Explanatory supplement

    NASA Astrophysics Data System (ADS)

    Wheelock, S. L.; Gautier, T. N.; Chillemi, J.; Kester, D.; McCallon, H.; Oken, C.; White, J.; Gregorich, D.; Boulanger, F.; Good, J.

    1994-05-01

    This Explanatory Supplement accompanies the IRAS Sky Survey Atlas (ISSA) and the ISSA Reject Set. The first ISSA release in 1991 covers completely the high ecliptic latitude sky, absolute value of beta is greater than 50 deg, with some coverage down to the absolute value of beta approx. equal to 40 deg. The second ISSA release in 1992 covers ecliptic latitudes of 50 deg greater than the absolute value of beta greater than 20 deg, with some coverage down to the absolute value of beta approx. equal to 13 deg. The remaining fields covering latitudes within 20 deg of the ecliptic plane are of reduced quality compared to the rest of the ISSA fields and therefore are released as a separate IPAC product, the ISSA Reject Set. The reduced quality is due to contamination by zodiacal emission residuals. Special care should be taken when using the ISSA Reject images. In addition to information on the ISSA images, some information is provided in this Explanatory Supplement on the IRAS Zodiacal History File (ZOHF), Version 3.0, which was described in the December 1988 release memo. The data described in this Supplement are available at the National Space Science Data Center (NSSDC) at the Goddard Space Flight Center. The interested reader is referred to the NSSDC for access to the IRAS Sky Survey Atlas (ISSA).

  4. IRAS Low Resolution Spectra of Asteroids

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Walker, Russell G.

    2002-01-01

    Optical/near-infrared studies of asteroids are based on reflected sunlight and surface albedo variations create broad spectral features, suggestive of families of materials. There is a significant literature on these features, but there is very little work in the thermal infrared that directly probes the materials emitting on the surfaces of asteroids. We have searched for and extracted 534 thermal spectra of 245 asteroids from the original Dutch (Groningen) archive of spectra observed by the IRAS Low Resolution Spectrometer (LRS). We find that, in general, the observed shapes of the spectral continua are inconsistent with that predicted by the standard thermal model used by IRAS. Thermal models such as proposed by Harris (1998) and Harris et al.(1998) for the near-earth asteroids with the "beaming parameter" in the range of 1.0 to 1.2 best represent the observed spectral shapes. This implies that the IRAS Minor Planet Survey (IMPS, Tedesco, 1992) and the Supplementary IMPS (SIMPS, Tedesco, et al., 2002) derived asteroid diameters are systematically underestimated, and the albedos are overestimated. We have tentatively identified several spectral features that appear to be diagnostic of at least families of materials. The variation of spectral features with taxonomic class hints that thermal infrared spectra can be a valuable tool for taxonomic classification of asteroids.

  5. IRAS sky survey atlas: Explanatory supplement

    NASA Technical Reports Server (NTRS)

    Wheelock, S. L.; Gautier, T. N.; Chillemi, J.; Kester, D.; Mccallon, H.; Oken, C.; White, J.; Gregorich, D.; Boulanger, F.; Good, J.

    1994-01-01

    This Explanatory Supplement accompanies the IRAS Sky Survey Atlas (ISSA) and the ISSA Reject Set. The first ISSA release in 1991 covers completely the high ecliptic latitude sky, absolute value of beta is greater than 50 deg, with some coverage down to the absolute value of beta approx. equal to 40 deg. The second ISSA release in 1992 covers ecliptic latitudes of 50 deg greater than the absolute value of beta greater than 20 deg, with some coverage down to the absolute value of beta approx. equal to 13 deg. The remaining fields covering latitudes within 20 deg of the ecliptic plane are of reduced quality compared to the rest of the ISSA fields and therefore are released as a separate IPAC product, the ISSA Reject Set. The reduced quality is due to contamination by zodiacal emission residuals. Special care should be taken when using the ISSA Reject images. In addition to information on the ISSA images, some information is provided in this Explanatory Supplement on the IRAS Zodiacal History File (ZOHF), Version 3.0, which was described in the December 1988 release memo. The data described in this Supplement are available at the National Space Science Data Center (NSSDC) at the Goddard Space Flight Center. The interested reader is referred to the NSSDC for access to the IRAS Sky Survey Atlas (ISSA).

  6. The IRAS 1 Jy Sample of Ultraluminous Infrared Galaxies. II. Optical Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kim, D.-C.; Veilleux, Sylvain; Sanders, D. B.

    1998-12-01

    This is the second paper in a series discussing the properties of ultraluminous infrared galaxies (ULIGs: LIR > 1012 L⊙ H0 = 75 km s-1 Mpc-1 and q0 = 0.0) from the 1 Jy sample of Kim. This paper presents the first results of a spectroscopic survey at optical wavelengths of a randomly selected subset of 45 ULIGs from Kim & Sanders. These new data are combined with previous data from Veilleux et al. to determine the spectral properties of luminous infrared galaxies (LIGs) with LIR ~ 1010.5-1013 L⊙. We find that the fraction of Seyfert galaxies among LIGs increases dramatically above LIR ~ 1012.3 L⊙--nearly one-half of the galaxies with LIR > 1012.3 L⊙ present Seyfert characteristics. Many of the optical properties of these Seyfert galaxies are consistent with the presence of genuine active galactic nuclei (AGNs) in the cores of these objects. The continuum colors and strengths of the stellar Hβ and Mg I b features in and out of the nuclei of ULIGs indicate that star formation has recently (~107 yr) taken place in the nuclear and circumnuclear regions of many of these objects. As expected, photoionization by hot stars appears to be the dominant source of ionization in the objects with H II region-like spectra. Evidence is presented that the ionization source in infrared-selected galaxies with nuclear LINER-like spectra (38% of the ULIGs in our sample) is likely to be shocks or of stellar origins rather than AGNs. Shock ionization associated with starburst-driven outflows may also explain the LINER-like emission detected outside the nuclei of some galaxies. No significant differences are found between the mean color excess of ULIGs and that of IRAS galaxies of lower infrared luminosity. However, in contrast to what was found in low-luminosity infrared galaxies, the color excess in the nuclei of ULIGs does not seem to depend on spectral types. The reddening in ULIGs is generally observed to decrease with distance from the nucleus as in their low

  7. The Most Luminous Supernovae

    NASA Astrophysics Data System (ADS)

    Sukhbold, Tuguldur; Woosley, S. E.

    2016-04-01

    Recent observations have revealed a stunning diversity of extremely luminous supernovae, seemingly increasing in radiant energy without bound. We consider simple approximate limits for what existing models can provide for the peak luminosity and total radiated energy for non-relativistic, isotropic stellar explosions. The brightest possible supernova is a Type I explosion powered by a sub-millisecond magnetar with field strength B ∼ few × {10}13 G. In extreme cases, such models might reach a peak luminosity of 2× {10}46 {erg} {{{s}}}-1 and radiate a total energy of up to 4× {10}52 {erg}. Other less luminous models are also explored, including prompt hyper-energetic explosions in red supergiants, pulsational-pair instability supernovae, pair-instability supernovae, and colliding shells. Approximate analytic expressions and limits are given for each case. Excluding magnetars, the peak luminosity is near 3× {10}44 {erg} {{{s}}}-1 for the brightest models and the corresponding limit on total radiated energy is 3× {10}51 {erg}. Barring new physics, supernovae with a light output over 3× {10}51 erg must be rotationally powered, either during the explosion itself or after, the most obvious candidate being a rapidly rotating magnetar. A magnetar-based model for the recent transient event, ASASSN-15lh is presented that strains, but does not exceed the limits of what the model can provide.

  8. Optical Spectroscopy of Luminous Infrared Galaxies. I. Nuclear Data

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

    A spectroscopic survey of a large sample of luminous infrared galaxies [log (L_ir_/L_sun_)^7^ ~ 10.5-12.5; H_0_ = 75 km s^-1^ Mpc^-1^] has been carried out using the Palomar 5 m telescope,, and the University of Hawaii 2.2 m telescope. Long-slit spectra covering 375o-8000 A at a resolution of ~10 A were obtained of 200 IRAS galaxies, including 114 objects from the IRAS Bright Galaxy Survey, and 86 objects with fainter infrared fluxes selected on the basis of their "warm" far-infrared (S_60_/S_100_) colors. The methods of observation and data reduction are discussed. An atlas of the spectra extracted from the nuclear region of these objects is presented along with a large number of parameters describing the properties of the emission lines, the stellar absorption lines, and the continuum emission that were measured from the spectra. An analysis of these data is presented in a companion paper (Veilleux et al. 1995) along with a discussion of the spatial variations of these parameters in a subsample of twenty-three objects.

  9. Deuterated water in the solar-type protostars NGC 1333 IRAS 4A and IRAS 4B

    NASA Astrophysics Data System (ADS)

    Coutens, A.; Vastel, C.; Cabrit, S.; Codella, C.; Kristensen, L. E.; Ceccarelli, C.; van Dishoeck, E. F.; Boogert, A. C. A.; Bottinelli, S.; Castets, A.; Caux, E.; Comito, C.; Demyk, K.; Herpin, F.; Lefloch, B.; McCoey, C.; Mottram, J. C.; Parise, B.; Taquet, V.; van der Tak, F. F. S.; Visser, R.; Yıldız, U. A.

    2013-12-01

    Context. The measure of the water deuterium fractionation is a relevant tool for understanding mechanisms of water formation and evolution from the prestellar phase to the formation of planets and comets. Aims: The aim of this paper is to study deuterated water in the solar-type protostars NGC 1333 IRAS 4A and IRAS 4B, to compare their HDO abundance distributions with other star-forming regions, and to constrain their HDO/H2O abundance ratios. Methods: Using the Herschel/HIFI instrument as well as ground-based telescopes, we observed several HDO lines covering a large excitation range (Eup/k = 22-168 K) towards these protostars and an outflow position. Non-local thermal equilibrium radiative transfer codes were then used to determine the HDO abundance profiles in these sources. Results: The HDO fundamental line profiles show a very broad component, tracing the molecular outflows, in addition to a narrower emission component and a narrow absorbing component. In the protostellar envelope of NGC 1333 IRAS 4A, the HDO inner (T ≥ 100 K) and outer (T < 100 K) abundances with respect to H2 are estimated with a 3σ uncertainty at 7.5-3.0+3.5 × 10-9 and 1.2-0.4+0.4 × 10-11, respectively, whereas in NGC 1333 IRAS 4B they are 1-0.9+1.8 × 10-8 and 1.2-0.4+0.6 × 10-10, respectively. Similarly to the low-mass protostar IRAS 16293-2422, an absorbing outer layer with an enhanced abundance of deuterated water is required to reproduce the absorbing components seen in the fundamental lines at 465 and 894 GHz in both sources. This water-rich layer is probably extended enough to encompass the two sources, as well as parts of the outflows. In the outflows emanating from NGC 1333 IRAS 4A, the HDO column density is estimated at about (2-4) × 1013 cm-2, leading to an abundance of about (0.7-1.9) × 10-9. An HDO/H2O ratio between 7 × 10-4 and 9 × 10-2 is also derived in the outflows. In the warm inner regions of these two sources, we estimate the HDO/H2O ratios at about 1 × 10

  10. Ongoing star formation in the protocluster IRAS 22134+5834

    NASA Astrophysics Data System (ADS)

    Wang, Yuan; Audard, Marc; Fontani, Francesco; Sánchez-Monge, Álvaro; Busquet, Gemma; Palau, Aina; Beuther, Henrik; Tan, Jonathan C.; Estalella, Robert; Isella, Andrea; Gueth, Frédéric; Jiménez-Serra, Izaskun

    2016-03-01

    Aims: Massive stars form in clusters, and their influence on nearby starless cores is still poorly understood. The protocluster associated with IRAS 22134+5834 represents an excellent laboratory for studying the influence of massive YSOs on nearby starless cores and the possible implications in the clustered star formation process. Methods: IRAS 22134+5834 was observed in the cm range with (E)VLA, 3 mm with CARMA, 2 mm with PdBI, and 1.3 mm with SMA, to study both the continuum emission and the molecular lines that trace different physical conditions of the gas. Results: The multiwavelength centimeter continuum observations revealed two radio sources within the cluster, VLA1 and VLA2. VLA1 is considered to be an optically thin UCHii region with a size of 0.01 pc that sits at the edge of the near-infrared (NIR) cluster. The flux of ionizing photons of the VLA1 corresponds to a B1 ZAMS star. VLA2 is associated with an infrared point source and has a negative spectral index. We resolved six millimeter continuum cores at 2 mm, MM2 is associated with the UCHii region VLA1, and other dense cores are distributed around the UCHii region. Two high-mass starless clumps (HMSC), HMSC-E (east) and HMSC-W (west), are detected around the NIR cluster with N2H+(1-0) and NH3 emission, and they show different physical and chemical properties. Two N2D+ cores are detected on an NH3 filament close to the UCHii region with a projected separation of ~8000 AU at the assumed distance of 2.6 kpc. The kinematic properties of the molecular line emission confirm that the UCHii region is expanding and that the molecular cloud around the NIR cluster is also expanding. Conclusions: Our multiwavelength study has revealed different generations of star formation in IRAS 22134+5834. The formed intermediate-to-massive stars show a strong impact on nearby starless clumps. We propose that the starless clumps and HMPOs formed at the edge of the cluster while the stellar wind from the UCHii region and the

  11. 26 CFR 1.408A-4 - Converting amounts to Roth IRAs.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the valuation methods in § 1.408A-4T (as it appeared in the April 1, 2008, edition of 26 CFR part 1... individual's SEP IRA or SIMPLE IRA to a Roth IRA? A-4. (a) An amount in an individual's SEP IRA can be... individual's SIMPLE IRA can be converted to a Roth IRA on the same terms as a conversion from a...

  12. 26 CFR 1.408A-4 - Converting amounts to Roth IRAs.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the valuation methods in § 1.408A-4T (as it appeared in the April 1, 2008, edition of 26 CFR part 1... individual's SEP IRA or SIMPLE IRA to a Roth IRA? A-4. (a) An amount in an individual's SEP IRA can be... individual's SIMPLE IRA can be converted to a Roth IRA on the same terms as a conversion from a...

  13. 26 CFR 1.408A-4 - Converting amounts to Roth IRAs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the valuation methods in § 1.408A-4T (as it appeared in the April 1, 2008, edition of 26 CFR part 1... individual's SEP IRA or SIMPLE IRA to a Roth IRA? A-4. (a) An amount in an individual's SEP IRA can be... individual's SIMPLE IRA can be converted to a Roth IRA on the same terms as a conversion from a...

  14. 26 CFR 1.408A-4 - Converting amounts to Roth IRAs.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the valuation methods in § 1.408A-4T (as it appeared in the April 1, 2008, edition of 26 CFR part 1... individual's SEP IRA or SIMPLE IRA to a Roth IRA? A-4. (a) An amount in an individual's SEP IRA can be... individual's SIMPLE IRA can be converted to a Roth IRA on the same terms as a conversion from a...

  15. Detection of glycolaldehyde toward the solar-type protostar NGC 1333 IRAS2A

    NASA Astrophysics Data System (ADS)

    Coutens, A.; Persson, M. V.; Jørgensen, J. K.; Wampfler, S. F.; Lykke, J. M.

    2015-04-01

    Glycolaldehyde is a key molecule in the formation of biologically relevant molecules such as ribose. We report its detection with the Plateau de Bure interferometer toward the Class 0 young stellar object NGC 1333 IRAS2A, which is only the second solar-type protostar for which this prebiotic molecule is detected. Local thermodynamic equilibrium analyses of glycolaldehyde, ethylene glycol (the reduced alcohol of glycolaldehyde), and methyl formate (the most abundant isomer of glycolaldehyde) were carried out. The relative abundance of ethylene glycol to glycolaldehyde is found to be ~5 - higher than in the Class 0 source IRAS 16293-2422 (~1), but similar to the lower limits derived in comets (≥3-6). The different ethylene glycol-to-glycolaldehyde ratios in the two protostars might be related to different CH3OH:CO compositions of the icy grain mantles. In particular, a more efficient hydrogenation on the grains in NGC 1333 IRAS2A would favor the formation of both methanol and ethylene glycol. In conclusion, it is possible that like NGC 1333 IRAS2A, other low-mass protostars show high ethylene glycol-to-glycolaldehyde abundance ratios. The cometary ratios might consequently be inherited from earlier stages of star formation if the young Sun experienced conditions similar to NGC 1333 IRAS2A. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).Figures 3-4 and Table 1 are available in electronic form at http://www.aanda.org

  16. Lidar Luminance Quantizer

    NASA Technical Reports Server (NTRS)

    Quilligan, Gerard; DeMonthier, Jeffrey; Suarez, George

    2011-01-01

    This innovation addresses challenges in lidar imaging, particularly with the detection scheme and the shapes of the detected signals. Ideally, the echoed pulse widths should be extremely narrow to resolve fine detail at high event rates. However, narrow pulses require wideband detection circuitry with increased power dissipation to minimize thermal noise. Filtering is also required to shape each received signal into a form suitable for processing by a constant fraction discriminator (CFD) followed by a time-to-digital converter (TDC). As the intervals between the echoes decrease, the finite bandwidth of the shaping circuits blends the pulses into an analog signal (luminance) with multiple modes, reducing the ability of the CFD to discriminate individual events

  17. IRAS 12556-7731: a "chamaeleonic" lithium-rich M-giant

    NASA Astrophysics Data System (ADS)

    Alcalá, J. M.; Biazzo, K.; Covino, E.; Frasca, A.; Bedin, L. R.

    2011-07-01

    Aims: In this letter we characterise IRAS 12556-7731 as the first lithium-rich M-type giant. Based on its late spectral type and high lithium content, and because of its proximity in angular distance to the Chamaeleon II star-forming region, the star was misclassified as a young low-mass star in a previous work. Methods: Based on HARPS data, synthetic spectral modelling, and proper motions, we derive the astrophysical parameters and kinematics of the star and discuss its evolutionary status. Results: This solar-mass red giant (Teff = 3460 ± 60 K and log g = 0.6 ± 0.2) is characterised by a relatively fast rotation (vsini ~ 8 km s-1), slightly subsolar metallicity and a high-lithium abundance, A(Li) = 2.4 ± 0.2 dex. We discuss IRAS 12556-7731 within the context of other known lithium-rich K-type giants. Because it is close to the tip of the red giant branch, IRAS 12556-7731 is the coolest lithium-rich giant known so far, and it is among the least massive and most luminous giants where enhancement of lithium has been detected. Among several possible explanations, we cannot preclude the possibility that the lithium enhancement and rapid rotation of the star were triggered by the engulfment of a brown dwarf or a planet. Based on HARPS observations collected at the La Silla Observations.Figure 4 and Appendix A are available in electronic form at http://www.aanda.org

  18. Chandra Observations of Diffuse Gas and Luminous X-Ray Sources around the X-Ray-bright Elliptical Galaxy NGC 1600

    NASA Astrophysics Data System (ADS)

    Sivakoff, Gregory R.; Sarazin, Craig L.; Carlin, Jeffrey L.

    2004-12-01

    We observed the X-ray-bright E3 galaxy NGC 1600 and nearby members of the NGC 1600 group with the Chandra X-Ray Observatory ACIS-S3 to study their X-ray properties. Unresolved emission dominates the observation; however, we resolved some of the emission into 71 sources, most of which are low-mass X-ray binaries associated with NGC 1600. Twenty-one of the sources have LX>2×1039 ergs s-1 (0.3-10.0 keV; assuming they are at the distance of NGC 1600), marking them as ultraluminous X-ray point source (ULX) candidates; we expect that only 11+/-2 are unrelated foreground/background sources. NGC 1600 may have the largest number of ULX candidates in an early-type galaxy to date; however, cosmic variance in the number of background active galactic nuclei cannot be ruled out. The spectrum and luminosity function (LF) of the resolved sources are more consistent with sources found in other early-type galaxies than with sources found in star-forming regions of galaxies. The source LF and the spectrum of the unresolved emission both indicate that there are a large number of unresolved point sources. We propose that these sources are associated with globular clusters (GCs) and that NGC 1600 has a large GC specific frequency. Observations of the GC population in NGC 1600 would be very useful for testing this prediction. Approximately 50%-75% of the unresolved flux comes from diffuse gaseous emission. The spectral fits, hardness ratios, and X-ray surface brightness profile all point to two gas components. We interpret the soft inner component (a<~25'', kT~0.85 keV) as the interstellar medium of NGC 1600 and the hotter outer component (a>~25'', kT~1.5 keV) as the intragroup medium of the NGC 1600 group. The X-ray image shows several interesting structures. First, there is a central region of excess emission that is roughly cospatial with Hα and dust filaments immediately west of the center of NGC 1600. There appear to be holes in the X-ray emission to the north and south of the

  19. A molecular line study of NGC 1333/IRAS 4

    NASA Technical Reports Server (NTRS)

    Blake, Geoffrey A.; Sandell, Goran; Van Dishoeck, Ewine F.; Groesbeck, T. D.; Mundy, Lee G.; Aspin, Colin

    1995-01-01

    Molecular line surveys and fully sampled spectral line maps at 1.3 and 0.87 mm are used to examine the physical and chemical characteristics of the extreme Class I sources IRAS 4A and 4B in the L1450/NGC 1333 molecular cloud complex. A very well collimated, jetlike molecular flow emanates from IRAS 4A, with a dynamical age of a few thousand years. Symmetric, clumpy structure along the outflow lobes suggests that there is considerable variability in the mass-loss rate or wind velocity even at this young age. Molecular emission lines toward IRAS 4A and 4B are observed to be weak in the velocity range corresponding to quiescent material surrounding the young stellar objects (YSOs). Depletion factors of 10-20 are observed for all molecules, including CO, even for very conservative mass estimates from the measured millimeter and submillimeter dust continuum. However, abundance scaled with respect to CO are similar to other dark molecular cloud cores. Such depletions could be mimicked by high dust and optical depths or increased grain emissivities at the observing frequencies of 230 and 435 GHz, but the millimeter and submillimeter spectral energy distributions suggest that this is unlikely over the single-dish size scales of 5000-10,000 AU. Dense, outflowing gas is found to be kinematically, but not spatially, distinct from the quiescent material on these size scales. If CO is used as a chemical standard for the high-velocity gas, we find substantial enhancements in abundances of several molecules in outflowing material, most notably CS, SIO, and CH3OH. The SiO emission is kinematically well displaced from the bulk cloud velocity and likely arises from directly shocked material. As is the case for CO, however, the outflow features from more volatile species are centered near the cloud velocity and are often characterized by quite low rotational temperatures. We suggest that grain-grain collisions induced by velocity shear zones surrounding the outflow axes transiently

  20. Complex Resonance Absorption Structure in the X-Ray Spectrum of IRAS 13349+2438

    NASA Technical Reports Server (NTRS)

    Sako, M.; Kahn, S. M.; Behar, E.; Kaastra, J. S.; Brinkman, A. C.; Boller, Th.; Puchnarewicz, E. M.; Starling, R.; Liedahl, D. A.; Clavel, J.

    2000-01-01

    The luminous infrared-loud quasar IRAS 13349+2438 was observed with the XMM - Newton Observatory as part of the Performance Verification program. The spectrum obtained by the Reflection Grating Spectrometer (RGS) exhibits broad (FWHM - 1400 km/s) absorption lines from highly ionized elements including hydrogen- and helium-like carbon, nitrogen, oxygen, and neon, and several iron L - shell ions (Fe XVII - XX). Also shown in the spectrum is the first astrophysical detection of a broad absorption feature around lambda = 16 - 17 A identified as an unresolved transition array (UTA) of 2p - 3d inner-shell absorption by iron M-shell ions in a much cooler medium; a feature that might be misidentified as an O VII edge when observed with moderate resolution spectrometers. No absorption edges are clearly detected in the spectrum. We demonstrate that the RGS spectrum of IRAS 13349+2438 exhibits absorption lines from two distinct regions, one of which is tentatively associated with the medium that produces the optical/UV reddening.

  1. Sensitive CO and 13CO survey of water fountain stars. Detections towards IRAS 18460-0151 and IRAS 18596+0315

    NASA Astrophysics Data System (ADS)

    Rizzo, J. R.; Gómez, J. F.; Miranda, L. F.; Osorio, M.; Suárez, O.; Durán-Rojas, M. C.

    2013-12-01

    Context. Water fountain stars represent a stage between the asymptotic giant branch (AGB) and planetary nebulae phases, when the mass loss changes from spherical to bipolar. These types of evolved objects are characterized by high-velocity jets in the 22 GHz water maser emission. Aims: The objective of this work is to detect and study in detail the circumstellar gas in which the bipolar outflows are emerging. The detection and study of thermal lines may help in understanding the nature and physics of the envelopes in which the jets are developing. Methods: We surveyed the CO and 13CO line emission towards a sample of ten water fountain stars through observing the J = 1 → 0 and 2 → 1 lines of CO and 13CO, using the 30 m IRAM radio-telescope at Pico Veleta. All the water fountains visible from the observatory were surveyed. Results: Most of the line emission arises from foreground or background Galactic clouds, and we had to thoroughly analyse the spectra to unveil the velocity components related to the stars. In two sources, IRAS 18460-0151 and IRAS 18596+0315, we identified wide velocity components with a width of 35 - 40 km s-1 that are centred at the stellar velocities. These wide components can be associated with the former AGB envelope of the progenitor star. A third case, IRAS 18286-0959, is reported as tentative; in this case a pair of narrow velocity components, symmetrically located with respect to the stellar velocity, have been discovered. We also modelled the line emission using an LVG code and derived some global physical parameters, which allowed us to discuss the possible origin of this gas in relation to the known bipolar outflows. For IRAS 18460-0151 and IRAS 18596+0315, we derived molecular masses close to 0.2 M⊙, mean densities of 104 cm-3, and mass-loss rates of 10-4 M⊙ yr-1. The kinetic temperatures are rather low, between 10 and 50 K in both cases, which suggests that the CO emission is arising from the outer and cooler regions of the

  2. High-luminance LEDs replace incandescent lamps in new applications

    NASA Astrophysics Data System (ADS)

    Evans, David L.

    1997-04-01

    The advent of high luminance AlInGaP and InGaN LED technologies has prompted the use of LED devices in new applications formally illuminated by incandescent lamps. The luminous efficiencies of these new LED technologies equals or exceeds that attainable with incandescent sources, with reliability factors that far exceed those of incandescent sources. The need for a highly efficient, dependable, and cost effective replacement for incandescent lamps is being fulfilled with high luminance LED lamps. This paper briefly described some of the new applications incorporating high luminance LED lamps, traffic signals and roadway signs for traffic management, automotive exterior lighting, active matrix and full color displays for commercial advertising, and commercial aircraft panel lighting and military aircraft NVG compatible lighting.

  3. Warm Molecular Gas in Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, N.; Zhao, Y.; Xu, C. K.; Gao, Y.; Armus, L.; Mazzarella, J. M.; Isaak, K. G.; Petric, A. O.; Charmandaris, V.; Díaz-Santos, T.; Evans, A. S.; Howell, J.; Appleton, P.; Inami, H.; Iwasawa, K.; Leech, J.; Lord, S.; Sanders, D. B.; Schulz, B.; Surace, J.; van der Werf, P. P.

    2014-06-01

    We present our initial results on the CO rotational spectral line energy distribution (SLED) of the J to J-1 transitions from J = 4 up to 13 from Herschel SPIRE spectroscopic observations of 65 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey. The observed SLEDs change on average from one peaking at J <= 4 to a broad distribution peaking around J ~ 6 to 7 as the IRAS 60-to-100 μm color, C(60/100), increases. However, the ratios of a CO line luminosity to the total infrared luminosity, L IR, show the smallest variation for J around 6 or 7. This suggests that, for most LIRGs, ongoing star formation (SF) is also responsible for a warm gas component that emits CO lines primarily in the mid-J regime (5 <~ J <~ 10). As a result, the logarithmic ratios of the CO line luminosity summed over CO (5-4), (6-5), (7-6), (8-7) and (10-9) transitions to L IR, log R midCO, remain largely independent of C(60/100), and show a mean value of -4.13 (\\equiv log R^SF_midCO) and a sample standard deviation of only 0.10 for the SF-dominated galaxies. Including additional galaxies from the literature, we show, albeit with a small number of cases, the possibility that galaxies, which bear powerful interstellar shocks unrelated to the current SF, and galaxies, in which an energetic active galactic nucleus contributes significantly to the bolometric luminosity, have their R midCO higher and lower than R^SF_midCO, respectively. Based on Herschel observations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  4. WARM MOLECULAR GAS IN LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Lu, N.; Zhao, Y.; Xu, C. K.; Mazzarella, J. M.; Howell, J.; Appleton, P.; Lord, S.; Schulz, B.; Gao, Y.; Armus, L.; Díaz-Santos, T.; Surace, J.; Isaak, K. G.; Petric, A. O.; Charmandaris, V.; Evans, A. S.; Inami, H.; Iwasawa, K.; Leech, J.; Sanders, D. B.; and others

    2014-06-01

    We present our initial results on the CO rotational spectral line energy distribution (SLED) of the J to J–1 transitions from J = 4 up to 13 from Herschel SPIRE spectroscopic observations of 65 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey. The observed SLEDs change on average from one peaking at J ≤ 4 to a broad distribution peaking around J ∼ 6 to 7 as the IRAS 60-to-100 μm color, C(60/100), increases. However, the ratios of a CO line luminosity to the total infrared luminosity, L {sub IR}, show the smallest variation for J around 6 or 7. This suggests that, for most LIRGs, ongoing star formation (SF) is also responsible for a warm gas component that emits CO lines primarily in the mid-J regime (5 ≲ J ≲ 10). As a result, the logarithmic ratios of the CO line luminosity summed over CO (5–4), (6–5), (7–6), (8–7) and (10–9) transitions to L {sub IR}, log R {sub midCO}, remain largely independent of C(60/100), and show a mean value of –4.13 (≡log R{sub midCO}{sup SF}) and a sample standard deviation of only 0.10 for the SF-dominated galaxies. Including additional galaxies from the literature, we show, albeit with a small number of cases, the possibility that galaxies, which bear powerful interstellar shocks unrelated to the current SF, and galaxies, in which an energetic active galactic nucleus contributes significantly to the bolometric luminosity, have their R {sub midCO} higher and lower than R{sub midCO}{sup SF}, respectively.

  5. Infrared Astronomical Satellite (IRAS) Catalogs and Atlases. Explanatory Supplement

    NASA Technical Reports Server (NTRS)

    Beichman, C. A. (Editor); Neugebauer, G. (Editor); Habing, H. J. (Editor); Clegg, P. E. (Editor); Chester, T. J. (Editor)

    1985-01-01

    The Infrared Astronomical Satellite (IRAS) mission is described. An overview of the mission, a description of the satellite and its telescope system, and a discussion of the mission design, requirements, and inflight modifications are given. Data reduction, flight tests, flux reconstruction and calibration, data processing, and the formats of the IRAS catalogs and atlases are also considered.

  6. IRAS constraints on the sizes of Pluto and Charon

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.; Veeder, Glenn J., Jr.; Dunbar, R. Scott; Lebofsky, Larry A.

    1987-01-01

    Thermal emission models indicate that Charon contributes a significant amount of the infrared radiation detected by IRAS during the observation of mutual eclipse events. The IRAS observations also show that the most probable diameters for Pluto and Charon are 2200 and 1300 (+ or - 150) km. These results are consistent with there being some atmosphere on Pluto.

  7. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  8. Circumstellar shells resolved in the IRAS survey data. I - Data processing procedure, results, and confidence tests

    NASA Technical Reports Server (NTRS)

    Young, K.; Phillips, T. G.; Knapp, G. R.

    1993-01-01

    We have examined the IRAS 60 and 100 micron survey data covering 512 evolved stars and young planetary nebulae for evidence of spatially resolved structure. A simple model, consisting of a central unresolved source surrounded by a resolved isothermal shell, was fitted to the data for each star. Seventy-six stars were found to be resolved in the 60 micron data. Tests have been performed to verify that the extended structure seen is not an artifact of the data-processing algorithm.

  9. The cluster of PMS stars in the vicinity of IRAS 05137+3919

    NASA Astrophysics Data System (ADS)

    Nikoghosyan, E. H.; Azatyan, N.

    2014-12-01

    We report the results of our study of the PMS stellar objects cluster in the vicinity of YSO CPM 15 which is associated with IRAS 05137+3919 source. The estimations of this cluster's distance are very inconsistent - from 4.3 kpc to 11 kpc. The KLF shows that nearer variant is more probable. Hence, with more probability, the pair of YSOs associated with CPM 15 is intermediate and not high mass objects, as was expected earlier.

  10. A redshift survey of IRAS galaxies. VII - The infrared and redshift data for the 1.936 Jansky sample

    NASA Technical Reports Server (NTRS)

    Strauss, Michael A.; Huchra, John P.; Davis, Marc; Yahil, Amos; Fisher, Karl B.; Tonry, John

    1992-01-01

    We present the data for a redshift survey of galaxies selected from the database of the Infrared Astronomical Satellite (IRAS). The sample is flux limited to 1.936 Jy at 60 microns and covers 11.01 sr of the sky. It consists of 5014 objects, of which 2658 are galaxies. The remaining 2356 sources are listed in a separate table with identifications. Redshift data are also given for 212 IRAS galaxies which are not part of the complete sample, but were measured in conjunction with this project.