Science.gov

Sample records for luminous iras source

  1. Evolution of luminous IRAS sources - Radio imaging

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    Observations of the compact radio morphology of 111 luminous IRAS-selected active galaxies covering a wide range of IR and optical properties are presented and discussed. Of these sources, 72 are observed for the first time with the VLA A configuration. The circumnuclear radio sources are generally small and weak, with 15 nondetections to a limit of about 0.4 mJy. Comparison with the IR and optical properties of the objects indicates that the radio sources turn on within 10 exp 8 yr of the tidal encounter that is presumed to generate the IR activity. However, the radio sources do not all appear at the same time. The radio observations are consistent with the evolution scenario for luminous IRAS galaxies suggested by Hutchings and Neff (1991).

  2. Evolution of luminous IRAS sources - CCD imaging

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    The paper presents optical imaging of a sample of 64 luminous IRAS galaxies which cover a wide range of IRAS spectra and luminosity and also include a range of optical types. The objects are almost all in current or recent tidal interaction. The connections between the strength and age of the interaction, the IR spectrum and luminosity, and the optical colors, and other properties of the galaxies are discussed. The principal result is that the powerful IR sources with steep IR spectra are stronger and dynamically younger interacting systems, while the flat IR spectrum objects are older. Star formation, dust obscuration, and the timescales for nuclear activity compared with IR and tidal events are discussed, and a self-consistent evolution scenario connecting the luminous IR sources is described.

  3. Optical counterparts of unidentified IRAS point sources Infrared luminous galaxies

    NASA Astrophysics Data System (ADS)

    Aaronson, M.; Olszewski, E. W.

    1984-05-01

    The results of a survey of deep, near-red pointlike objects using mainly the IRAS CCD array focused on sources emitting in the 60 micron region are reported. Data were gathered on 0358 + 223, 0404 + 101, 0412 + 085, 0413 + 122, 0422 + 009 and 0425 + 012. Photometric data of these and other objects are provided in terms of R - I colors. Spectra were obtained for 0422 + 009 and 0425 + 012. The IRAS data indicated that the sources are high intensity IR galaxies. The intense emissions may arise from star formation bursts or an embedded active Seyfert nucleus. Further spectroscopic and radio observations are required to characterize the sources of the IR emissions more accurately.

  4. The hidden nuclear spectrum of the luminous IRAS source FSC 10214+4724

    NASA Technical Reports Server (NTRS)

    Jannuzi, Buell T.; Elston, Richard; Schmidt, Gary D.; Smith, Paul S.; Stockman, H. S.

    1994-01-01

    Optical spectropolarimetry of the luminous IRAS source FSC 10214+4724 (z=2.286) reveals that the strong (approximately 17%) linear polarization detected by Lawrence et al. is shared by both the narrow ultraviolet (UV) emission lines and the underlying continuum. This observation and the brightness of the source rule out synchrotron emission and dichroic extinction by dust as the polarizing mechanism, leaving scattering as the only plausible cause of the polarized emission. The narrowness of the lines requires that the scatterers be dust grains or cool (below 1.6 x 10(exp 4) K) electrons. We can recover the spectrum that is incident on the scattering medium provided we make some reasonable assumptions regarding the source geometry. The scattered UV spectrum has a power-law index alpha of -1.2 plus or minus 0.6 (F(sub nu) varies as nu(sup alpha)), steeper than would be expected from a young burst of star formation but similar to that of many active galactic nucleus (AGNs).

  5. 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.

  6. HST Observations of the Luminous IRAS Source FSC10214+4724: A Gravitationally Lensed Infrared Quasar

    NASA Technical Reports Server (NTRS)

    Eisenhardt, P. R.; Armus, L.; Hogg, D. W.; Soifer, B. T.; Neugebauer, G.; Werner, M. W.

    1995-01-01

    Hubble Space Telescope (HST) data taken of the IRAS source FSC 10214+4724 suggest that the object has been gravitationally lensed by a galaxy in the foreground and that this lensing may be magnifying the apparent brightness by roughly 100 times.

  7. Radio observations of nearby moderately luminous IRAS galaxies.

    NASA Astrophysics Data System (ADS)

    Li, Yongsheng; Su, Bumei

    1999-05-01

    Six nearby moderately luminous IRAS galaxies have been observed at two wavelength by using the Australian AT. Among them, radio emissions have been detected for two galaxies, i.e. IRAS 20272-4738 and IRAS 23156-4238, and their radio parameters, like radio fluxes, peak positions, source sizes and spectral indices, are obtained. The radio sources are confirmed with infrared, radio and optical observations. Some characteristics of the radio emissions of these galaxies are discussed with previous observational data.

  8. Radio observations of nearby moderately luminous IRAS galaxies

    NASA Astrophysics Data System (ADS)

    Li, Yong-sheng; Su, Bu-mei

    Six nearby moderately luminous IRAS galaxies have been observed at two wavelengths with the Australia Telescope Compact Array. Radio emission was detected in two of them, IRAS 20272-4738 and IRAS 23156-4238, and their parameters including flux, peak position, size and spectral index, obtained. These sources were confirmed with infrared, radio and optical data. Combining with previous results we discuss their emission characteristics.

  9. 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.

  10. 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.

  11. 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.

  12. HST Observations of the Luminous IRAS Source FSC10214+4724: A gravitationally Lensed Infrared Quasar

    NASA Technical Reports Server (NTRS)

    Eisenhardt, P. R.; Armus, L.; Hogg, D. W.; Soifer, B. T.; Neugebauer, G.; Werner, M. W.

    1995-01-01

    Observations of a distant object in space with the data being taken by the Hubble Space Telescope (HST) Wide Field Planetary Camera. Scientific examination and hypothesis related to this object which appears to be either an extremely luminous dust embedded quasar, or a representative of a new class of astronomical objects (a primeval galaxy).

  13. The properties of highly luminous IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Wolstencroft, R. D.; Puxley, P. J.; Heasley, J. N.; Leggett, S. K.; Savage, A.; Macgillivray, H. T.; Clowes, R. G.

    1987-01-01

    From a complete sample of 154 galaxies identified with IRAS sources in a 304 sq deg area centered on the South Galactic Pole, a subsample of 58 galaxies with L sub IR/L sub B > 3 was chosen. Low resolution spectra were obtained for 30% of the subsample and redshifts and relative emission line intensities were derived. As a class these galaxies are very luminous with < L sub IR > = 2.9 x 10 to the 11th power L sub 0 and (L sub IR) max = 1.3 x 10 to the 12th power L sub 0. CCD images and JHK photometry were obtained for many of the subsample. The galaxies are for the most part newly identified and are optically faint, with a majority showing evidence of a recent interaction. Radio continuum observations of all galaxies of the subsample were recently obtained at 20 cm VLA with about 75% being detected in a typical integration time of about 10 minutes.

  14. 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.

  15. 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.

  16. IUE and IRAS observations of luminous M stars with varying gas-to dust ratios

    NASA Technical Reports Server (NTRS)

    Hagen, W.; Carpenter, K. G.; Stencel, R. E.

    1986-01-01

    Circumstellar gas and dust surrounding M giants and supergiants show luminous M stars to split into two distinct classes. Stars with a high gas to dust ratio all show chromospheric Ca II, H, and K emission. Stars with a high dust to gas ratio do not show chromospheric Ca II emission but are the only ones to show Balmer emission indicative of atmospheric shocks and are also the only ones to show maser emission. In order to determine whether all chromospheric indicators disappear in high dust to gas ratio stars, a survey of stars in both these classes was conducted with the IUE satellite. Long wavelength infrared fluxes for the program stars were obtained from the IRAS point source catalog. There is no obvious difference in the long wavelength observations between the two groups of stars. The long wavelength excess tends to follow the 10 micron excess and not the dust to gas ratio.

  17. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  20. High-resolution CO observations of luminous infrared galaxies with large L(ir)/L(B) ratios - IRAS 10173 + 0828, Zw 049.057, IRAS 17208 - 0014

    NASA Technical Reports Server (NTRS)

    Planesas, P.; Mirabel, I. F.; Sanders, D. B.

    1991-01-01

    The Owens Valley mm-wave interferometer has been used for high-resolution (about 3-7 arcsec) mapping of CO emission in three luminous IRAS galaxies: IRAS 17208 - 0014, 15107 + 0724, and IRAS 10173 + 0828. These galaxies are among the most extreme, in terms of their L(ir)/L(B) ratio, for objects in the IRAS Bright Galaxy Surveys. The CO emission detected in the three galaxies originates from a single region centered on the IRAS emission peak. These observations have shown that these galaxies have similar values for the global L(ir)/M(H2) ratio, for the surface density of molecular gas in their central regions and for the extinction toward the nucleus (above 300 mag). A high L(ir)/L(B) ratio seems to be a good predictor for both a high global L(ir)/M(H2) ratio and very large central H2 surface densities.

  1. Systematic identification of IRAS point sources

    NASA Technical Reports Server (NTRS)

    Savage, A.; Clowes, R. G.; Macgillivray, H. T.; Wolstencroft, R. D.; Leggett, S. K.; Puxley, P. J.

    1987-01-01

    A large scale program was initiated to identify IRAS point sources. At ROE the ideal facilities are at hand to undertake such a large program, viz. the rapid scanning capabilities of the COSMOS measuring machine to exploit the depth and resolution of the U.K. Schmidt Telescope J survey plates. Sources in 44 Schmidt plate areas were identified including 1300 sources and covering 1100 square degrees. The identification comprise 700 galaxy identifications and 600 stellar identifications. There are also about 40 sources with no obvious identification but which can be most easily explained by cirrus, confusion between two sources or sources just outside the 2 sigma error box. A major aim with the galaxy identification is to provide a data base from which sound statistical analyses can be made. Accurate blue magnitudes and morphological classifications for each identification were produced.

  2. Discovery of luminous near-infrared transient AT 2017gbl in IRAS 23436+5257

    NASA Astrophysics Data System (ADS)

    Kool, E. C.; Ryder, S.; Mattila, S.; Reynolds, T.; Cannizzaro, G.; Kankare, E.; McDermid, R.; Fraser, M.; Perez-Torres, M.; Wevers, T.; Jonker, P.; Vaisanen, P.; Sweet, S.; Tucker, B. E.

    2017-08-01

    As part of a near-infrared adaptive optics assisted search for nuclear core-collapse supernovae in luminous infrared galaxies (project SUNBIRD) we report on the discovery of AT 2017gbl, a luminous transient superimposed on the northern nucleus of IRAS 23436+5257 at (RA, Dec.) = 23:46:05.53 +53:14:01.06, observed in JHKs with NIRC2 on Keck on 2017 July 8.56 UT. Subtraction with NIRC2 reference imaging from 2016 Oct 21 yielded near-infrared magnitudes of 13.3 (0.1) in Ks, 14.5 (0.1) in H and 16.0 (0.1) in J. Assuming a host luminosity distance of 146 Mpc (NED, H0 = 70 km s-1 Mpc-1), this yields an absolute magnitude in Ks of -22.5, not corrected for extinction.

  3. 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.

  4. 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.

  5. Chandra X-ray observations of the hyper-luminous infrared galaxy IRAS F15307+3252

    NASA Astrophysics Data System (ADS)

    Hlavacek-Larrondo, J.; Gandhi, P.; Hogan, M. T.; Gendron-Marsolais, M.-L.; Edge, A. C.; Fabian, A. C.; Russell, H. R.; Iwasawa, K.; Mezcua, M.

    2017-01-01

    Hyper-luminous infrared galaxies (HyLIRGs) lie at the extreme luminosity end of the IR galaxy population with LIR > 1013 L⊙. They are thought to be closer counterparts of the more distant sub-millimeter galaxies, and should therefore be optimal targets to study the most massive systems in formation. We present deep Chandra observations of IRAS F15307+3252 (100 ks), a classical HyLIRG located at z = 0.93 and hosting a radio-loud AGN (L1.4 GHz ˜ 3.5 × 1025 W Hz-1). The Chandra images reveal the presence of extended (r = 160 kpc), asymmetric X-ray emission in the soft 0.3-2.0 keV band that has no radio counterpart. We therefore argue that the emission is of thermal origin originating from a hot intragroup or intracluster medium virializing in the potential. We find that the temperature (˜2 keV) and bolometric X-ray luminosity (˜3 × 1043 erg s-1) of the gas follow the expected LX-ray-T correlation for groups and clusters, and that the gas has a remarkably short cooling time of 1.2 Gyr. In addition, VLA radio observations reveal that the galaxy hosts an unresolved compact steep-spectrum (CSS) source, most likely indicating the presence of a young radio source similar to 3C186. We also confirm that the nucleus is dominated by a redshifted 6.4 keV Fe Kα line, strongly suggesting that the AGN is Compton-thick. Finally, Hubble images reveal an overdensity of galaxies and sub-structure in the galaxy that correlates with soft X-ray emission. This could be a snapshot view of on-going groupings expected in a growing cluster environment. IRAS F15307+3252 might therefore be a rare example of a group in the process of transforming into a cluster.

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1993-05-01

    We (Elston et al. 1993) have observed the rest frame optical and UV spectra of the luminous, high redshift IRAS galaxy FSC10214+4724. We find the [NII]/Hα and [OIII]/Hβ emission line ratios to be typical of those found in Seyfert II galaxies. The large Hα /Hβ ratio suggests substantial reddening of the narrow line region. The rest-frame optical emission is unpolarized (P=2.6+/-3.0%). These properties are very similar to those of the infrared luminous galaxies found at lower redshift, suggesting that FSC10214+4724 is the luminous extreme of the same population. A deep 1.6microns image of the field shows FSC10214+4724 to be unresolved with two nearby companions and several other faint objects within 10('') of the point source. These could be a a foreground group of galaxies or galaxies physically associated with FSC10214+4724. This aggregate of objects may have contributed some of the far-infrared flux detected within the large beam of IRAS. If there is a foreground group gravitational lensing may contribute to the large luminosity of FSC10214+4724.

  8. Herschel observations and a model for IRAS 08572+3915: a candidate for the most luminous infrared galaxy in the local (z < 0.2) Universe

    NASA Astrophysics Data System (ADS)

    Efstathiou, A.; Pearson, C.; Farrah, D.; Rigopoulou, D.; Graciá-Carpio, J.; Verma, A.; Spoon, H. W. W.; Afonso, J.; Bernard-Salas, J.; Clements, D. L.; Cooray, A.; Cormier, D.; Etxaluze, M.; Fischer, J.; González-Alfonso, E.; Hurley, P.; Lebouteiller, V.; Oliver, S. J.; Rowan-Robinson, M.; Sturm, E.

    2014-01-01

    We present Herschel photometry and spectroscopy, carried out as part of the Herschel ultraluminous infrared galaxy (ULIRG) survey, and a model for the infrared to submillimetre emission of the ULIRG IRAS 08572+3915. This source shows one of the deepest known silicate absorption features and no polycyclic aromatic hydrocarbon emission. The model suggests that this object is powered by an active galactic nucleus (AGN) with a fairly smooth torus viewed almost edge-on and a very young starburst. According to our model, the AGN contributes about 90 per cent of the total luminosity of 1.1 × 1013 L⊙, which is about a factor of 5 higher than previous estimates. The large correction of the luminosity is due to the anisotropy of the emission of the best-fitting torus. Similar corrections may be necessary for other local and high-z analogues. This correction implies that IRAS 08572+3915 at a redshift of 0.058 35 may be the nearest hyperluminous infrared galaxy and probably the most luminous infrared galaxy in the local (z < 0.2) Universe. IRAS 08572+3915 shows a low ratio of [C II] to IR luminosity (log L[CII]/LIR < -3.8) and a [O I]63 μm to [C II]158 μm line ratio of about 1 that supports the model presented in this Letter.

  9. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, Rosanne; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    This grant was for the study of Luminous Supersoft X-Ray Sources (SSSs). During the first year a number of projects were completed and new projects were started. The projects include: 1) Time variability of SSSs 2) SSSs in M31; 3) Binary evolution scenarios; and 4) Acquiring new data.

  10. 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.

  11. New CO and HCN sources associated with IRAS carbon stars

    NASA Technical Reports Server (NTRS)

    NGUYEN-Q-RIEU; Epchtein, N.; TRUONG-BACH; Cohen, M.

    1987-01-01

    Emission of CO and HCN was detected in 22 out of a sample of 53 IRAS sources classified as unidentified carbon-rich objects. The sample was selected according to the presence of the silicon carbide feature as revealed by low-resolution spectra. The molecular line widths indicate that the CO and HCN emission arises from the circumstellar envelopes of very highly evolved stars undergoing mass loss. The visible stars tend to be deficient in CO as compared with unidentified sources. Most the detected CO and HCN IRAS stars are distinct and thick-shelled objects, but their infrared and CO luminosities are similar to those of IRC + 102156 AFGL and IRC-CO evolved stars. The 12 micron flux seems to be a good indicator of the distance, hence a guide for molecular searches.

  12. 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.

  13. Near-infrared observations of the z about 2.3 IRAS source FSC 10214 + 4724

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.; Neugebauer, G.; Graham, J. R.; Matthews, K.; Mazzarella, J. M.; Lonsdale, C. J.; Rowan-Robinson, M.; Broadhurst, T.; Lawrence, A.; Mcmahon, R.

    1991-01-01

    Near-infrared imaging and spectroscopy of the extremely luminous IRAS source FSC 10214 + 4724 have been obtained using the Cassegrain infrared camera on the 200-inch Hale Telescope. A low-resolution spectrum in the 2.0-2.4 micron atmospheric window shows a very strong H-alpha line at the optically determined redshift z = 2.286. The observed rest-frame equivalent width of H-alpha is 0.07 +/-0.02 microns, consistent with the largest values found in quasars. The images show an unresolved source, while the near-infrared colors are somewhat redder than the mean colors of quasars observed at the same redshift. The reddening inferred is about 1.5 mag, with an upper limit of about 3.0 mag. If FSC 10214 + 4724 is a quasar, the reddening-corrected bolometric luminosity is approximately equal to the observed infrared luminosity.

  14. 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.

  15. CO J = 3-2 Emission from the ``Water Fountain'' Sources IRAS 16342-3814 and IRAS 18286-0959

    NASA Astrophysics Data System (ADS)

    Imai, Hiroshi; He, Jin-Hua; Nakashima, Jun-Ichi Ukita, Nobuharu; Deguchi, Shuji; Koning, Nico

    2009-12-01

    We observed CO J = 3-2 emission from ``water-fountain'' sources, which exhibit high-velocity collimated stellar jets traced by H2O maser emission, with the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope. We detected CO emission from two sources: IRAS 16342-3814 and IRAS 18286-0959. The IRAS 16342-3814 CO emission exhibits a spectrum that could be well fit to a Gaussian profile, rather than to a parabolic profile, with a velocity width (FWHM) of 158±6km s-1 and an intensity peak at VLSR = 50±2 km s-1. The mass-loss rate of the star is estimated to be ˜2.9 × 10-5Modot yr-1. Our morpho-kinematic models suggest that the CO emission is optically thin, and associated with a bipolar outflow rather than with a (cold and relatively small) torus. The IRAS 18286-0959 CO emission has a velocity width (FWHM) of 3.0±0.2 km s-1, smaller than typically seen in AGB envelopes. The narrow velocity width of the CO emission suggests that it originates from either an interstellar molecular cloud or a slowly-rotating circumstellar envelope that harbors the H2O maser source.

  16. 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.

  17. 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

  18. 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.

  19. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); DiStefano, Rosanne

    2003-01-01

    We have made remarkable progress in the study of luminous supersoft X-ray sources during the past year. We have begun to discover a population of ultraluminous SSSs (e.g., in NGC 300 [Kong & Di Stefano 20031 as well as in Ml0l [Di Stefano & Kong 2003]), which may be accreting intermediate-mass (50-100 solar mass) black holes. This work follows from an algorithm we have developed (Di Stefano & Kong 2003) to identify SSSs in external galaxies, selecting them from among each galaxy s total population of X-ray sources. We have applied the algorithm to approximately one dozen galaxies and will make it public after it has been published in its entirety. Through our own application of the algorithm, we have discovered SSSs in every galaxy, mapping their spatial distribution, to obtain important clues to their fundamental natures. We have discovered that there is a large population of X-ray sources which are slightly hotter (100-250 eV) than standard SSSs. Some of these may be accreting BHs with masses between roughly 50 anf 100 solar masses. To explore this possibility, we are working on theoretical models for the formation and evolution of such systems (Di Stefano 2003).

  20. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); DiStefano, Rosanne

    2003-01-01

    We have made remarkable progress in the study of luminous supersoft X-ray sources during the past year. We have begun to discover a population of ultraluminous SSSs (e.g., in NGC 300 [Kong & Di Stefano 20031 as well as in Ml0l [Di Stefano & Kong 2003]), which may be accreting intermediate-mass (50-100 solar mass) black holes. This work follows from an algorithm we have developed (Di Stefano & Kong 2003) to identify SSSs in external galaxies, selecting them from among each galaxy s total population of X-ray sources. We have applied the algorithm to approximately one dozen galaxies and will make it public after it has been published in its entirety. Through our own application of the algorithm, we have discovered SSSs in every galaxy, mapping their spatial distribution, to obtain important clues to their fundamental natures. We have discovered that there is a large population of X-ray sources which are slightly hotter (100-250 eV) than standard SSSs. Some of these may be accreting BHs with masses between roughly 50 anf 100 solar masses. To explore this possibility, we are working on theoretical models for the formation and evolution of such systems (Di Stefano 2003).

  1. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); DiStefano, Roseanne

    2005-01-01

    One of the key accomplishments of the two preceding years was our development of an algorithm to select SSSs in external galaxies which have been observed by Chandra or XMM-Newton. By applying this algorithm to data from a number of galaxies, we discovered an extension of the class of SSSs to sources that are somewhat harder (100 - 300 eV, instead of tens of eV), but which are nevertheless much softer than canonical X-ray sources. We call these new sources quasisoft sources (QSSs). During this past year, we have built on and extended this work. We have (1) continued to identify SSSs and QSSs in external galaxies, (2) worked on models for the sources and find that black hole models seem promising for a subset of them, and (3) have studied individual systems, especially M101-ULX1. This special system has been observed as an SSS in its high &ate, with a luminosity in excess of 10(exp 41) erg/s. It has also been observed as a QSS when it is less luminous, and as a hard source in its low state. It is one of the best candidates to be an accreting intermediate-mass black hole. We have several papers in preparation. Below we list papers which are complete, including only new work and papers whose status has changed (e.g., been accepted for publication) since our last report. In addition, our work on QSSs has received some publicity. It was the subject of a Chandra press release and was picked up by several media outlets.

  2. 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.

  3. Near-infrared Imaging of Unidentified IRAS Sources

    NASA Astrophysics Data System (ADS)

    Meyer, A. W.; Rank, D.; Gilmore, K.; Temi, P.

    1992-05-01

    The performance of near-infrared imaging arrays permits photometry and mapping of infrared sources with an efficiency comparable to that provided in the visible by CCD's. An imaging survey of a target list to obtain near-infrared positions, magnitudes and morphology can be pursued at a rate limited by telescope slewing and pointing speed. The Lick Observatory NICMOS array camera was used on an instrument time-available basis to search for any near-infrared counterparts to a sample of unidentified entries in the IRAS Point Source Catalog (PSC). 36 candidates for imaging were selected from 900 unidentified PSC sources (NID=0) within a 30-degree diameter area. Additional criteria used to produce a short list of candidates included flux > 1 Jansky, good flux quality, and 2-band colors similar to those of galaxies, or at least not those of stellar photospheres. Many of the candidates were found to coincide with anonymous galaxies on the Palomar Sky Survey prints. Most of the sources observed are bright in the near-infrared, with J or K magnitudes in the range of 11 to 13.

  4. 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.

  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. VizieR Online Data Catalog: Ammonia on YSOs IRAS sources (Molinari+ 1996)

    NASA Astrophysics Data System (ADS)

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

    1996-04-01

    We present observations of NH3 (1,1) and (2,2) lines flux-limited samples of IRAS sources selected according to colour criteria which should result in a high fraction of Young Stellar Objects. The first sample contains sources (named 'LOW') whose evolutionary status is essentially unknown, while the second sample contains sources (named 'HIGH') possibly associated with ultracompact HII regions, the distinction being based on the IRAS [25-12] colour. (2 data files).

  7. 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.

  8. The topology of the IRAS Point Source Catalogue Redshift Survey

    NASA Astrophysics Data System (ADS)

    Canavezes, A.; Springel, V.; Oliver, S. J.; Rowan-Robinson, M.; Keeble, O.; White, S. D. M.; Saunders, W.; Efstathiou, G.; Frenk, C. S.; McMahon, R. G.; Maddox, S.; Sutherland, W.; Tadros, H.

    1998-07-01

    We investigate the topology of the new Point Source Catalogue Redshift Survey (PSCz) of IRAS galaxies by means of the genus statistic. The survey maps the local Universe with approximately 15 000 galaxies over 84.1 per cent of the sky, and provides an unprecedented number of resolution elements for the topological analysis. For comparison with the PSCz data we also examine the genus of large N-body simulations of four variants of the cold dark matter (CDM) cosmogony. The simulations are part of the Virgo project to simulate the formation of structure in the Universe. We assume that the statistical properties of the galaxy distribution can be identified with those of the dark matter particles in the simulations. We extend the standard genus analysis by examining the influence of sampling noise on the genus curve and introducing a statistic able to quantify the amount of phase correlation present in the density field, the amplitude drop of the genus compared to a Gaussian field with identical power spectrum. The results for PSCz are consistent with the hypothesis of random-phase initial conditions. In particular, no strong phase correlation is detected on scales ranging from 10 to 32 h^-1 Mpc, whereas there is a positive detection of phase correlation at smaller scales. Among the simulations, phase correlations are detected in all models at small scales, albeit with different strengths. When scaled to a common normalization, the amplitude drop depends primarily on the shape of the power spectrum. We find that the constant-bias standard CDM model can be ruled out at high significance, because the shape of its power spectrum is not consistent with PSCz. The other CDM models with more large-scale power all fit the PSCz data almost equally well, with a slight preference for a high-density tauCDM model.

  9. Infrared properties of molecular cirrus. I - Photometry of extended sources on IRAS image products

    NASA Astrophysics Data System (ADS)

    Verter, Frances; Rickard, Lee J.

    1998-02-01

    We have conducted a survey of IRAS images of the high-latitude molecular cirrus clouds cataloged by Magnani et al. (1985). This paper reports the data reduction methods used in our survey and also studies the photometric accuracy that can be achieved for faint extended sources on IRAS image products. The principal topics covered are the modeling and removal of sky backgrounds at high Galactic latitude, and as a function of ecliptic latitude; the relative accuracy of different background models and methods of background removal; the integration of source flux on background-subtracted images; the proper definition of flux error bars, their calculation, and the minimum uncertainties set by the performance of the IRAS detectors; the creation of multiple-wavelength composite images; and the creation of temperature and opacity maps. We find that most error bars quoted for IRAS fluxes in the literature are incorrect. We conclude that the limiting surface brightness to which Sky Flux Plates may be used to study faint extended sources is approximately 0.05 MJy/sr. The photometric issues discussed herein are relevant to all IRAS image products, including Sky Flux Plates, co-added images, and the IRAS Sky Survey Atlas (ISSA). We compare the accuracy of data reduction on different products and discuss their relative advantages and disadvantages.

  10. IRAS 18455+0448: An OH Fountain Source

    NASA Astrophysics Data System (ADS)

    Lewis, B. M.

    2015-08-01

    IRAS 18455+0448 has been monitored annually since its 1612 MHz masers disappeared in 2001. At Xmas 2012, an intense, new, 1665 MHz feature at ˜3ve appeared, which points to the initiation of a jet in this post-AGB star.

  11. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, Rosanne; Oliversen, Ronald J. (Technical Monitor)

    2004-01-01

    This has been a remarkably productive year. We have completed an algorithm to select SSSs in external galaxies which have been observed by Chandru or XMM-Newton. By applying this algorithm to new data, we have discovered an extension of the class of SSSs to sources that are somewhat harder (100 - 300 eV, instead of tens of eV), but which are nevertheless much softer than canonical X-ray sources. We have completed a study of SSSs in M31 and have also considered several other galaxies. From these studies, some population characteristics are beginning to emerge; these provide clues to the natures of the systems. We have considered ultraluminous SSSs in M1O1 and NGC 300. It is possible that these may correspond to accreting intermediate-mass black holes, rather than accreting white dwarfs. We have also studied individual systems, such as CAL 83, and have followed up on additional sources in fields we have studied, such as in the galaxy NGC 1313. NASA has released a press release on some of our work.

  12. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, Rosanne; Oliversen, Ronald J. (Technical Monitor)

    2004-01-01

    This has been a remarkably productive year. We have completed an algorithm to select SSSs in external galaxies which have been observed by Chandru or XMM-Newton. By applying this algorithm to new data, we have discovered an extension of the class of SSSs to sources that are somewhat harder (100 - 300 eV, instead of tens of eV), but which are nevertheless much softer than canonical X-ray sources. We have completed a study of SSSs in M31 and have also considered several other galaxies. From these studies, some population characteristics are beginning to emerge; these provide clues to the natures of the systems. We have considered ultraluminous SSSs in M1O1 and NGC 300. It is possible that these may correspond to accreting intermediate-mass black holes, rather than accreting white dwarfs. We have also studied individual systems, such as CAL 83, and have followed up on additional sources in fields we have studied, such as in the galaxy NGC 1313. NASA has released a press release on some of our work.

  13. A practical approach to the classification of IRAS sources using infrared colors alone

    NASA Technical Reports Server (NTRS)

    Walker, Helen J.; Volk, Kevin; Wainscoat, Richard J.; Schwartz, Deborah E.; Cohen, Martin

    1989-01-01

    Zones of the IRAS color-color planes in which a variety of different types of known source occur, have been defined for the purpose of obtaining representative IRAS colors for them. There is considerable overlap between many of these zones, rendering a unique classification difficult on the basis of IRAS colors alone, although galactic latitude can resolve ambiguities between galactic and extragalactic populations. The color dependence of these zones on the presence of spectral emission/absorption features and on the spatial extent of the sources has been investigated. It is found that silicate emission features do not significantly influence the IRAS colors. Planetary nebulae may show a dependence of color on the presence of atomic or molecular features in emission, although the dominant cause of this effect may be the underlying red continua of nebulae with strong atomic lines. Only small shifts are detected in the colors of individual spatially extended sources when total flux measurements are substituted for point-source measurements.

  14. 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

  15. 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

  16. Identification of new young stellar objects associated with IRAS point sources. III. The northern Galactic plane

    SciTech Connect

    Campbell, B.; Persson, S.E.; Matthews, K.; New Mexico Univ., Albuquerque; Palomar Observatory, Pasadena, CA )

    1989-08-01

    A third list of new candidate young stellar objects found by searching the vicinities of IRAS positions along the galactic plane is presented. The list comprises 40 new objects in 39 fields with 2.2-micron magnitudes brighter than 10.5, and with near-infrared colors similar to those of fiducial objects such as GL 490. An additional 12 objects are identified as probable YSOs on the basis of incomplete data. Positions accurate to + or - 2 arcsec and deep red CCD pictures of 31 of the fields are given. Contemporaneous 10-micron observations allow an assessment of the reliability of the identifications; at least 80 percent of the near-infrared sources are directly related to the IRAS source, and the remainder are probably associated, but may not be the exciting sources of the regions. 11 refs.

  17. Recent Results on Ultra-Luminous X-ray Sources

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard

    2005-01-01

    I will summarize what is known about the properties of the ultra-luminous x-ray sources with particular emphasis on their x-ray spectral and temporal properties, their radio counterparts and the environments in which they are located. These results are based on a large XMM survey of nearby galaxies VLA radio observations, recent XMM timing and spectral observations as well has HST and Gemini observations and a review of the literature. I will discuss how our present knowledge fits in with estimates of their mass and whether these objects are 'intermediate mass' black holes or stellar mass black holes in a very unusual state.

  18. The derived population of luminous supersoft X-ray sources

    NASA Technical Reports Server (NTRS)

    Di Stefano, R.STEFANO; Rappaport, S.

    1994-01-01

    The existence of a new class of astrophysical object, luminous supersoft X-ray sources, has been established through ROSAT satellite observations and analysis during the past approximately 3 yr. Because most of the radiation emitted by supersoft sources spans a range of wavelengths readily absorbed by interstellar gas, a substantial fraction of these sources may not be detectable with present satellite instrumentation. It is therefore important to derive a reliable estimate of the underlying population, based on the approximately 30 sources that have been observed to date. The work reported here combines the observational results with a theoretical analysis, to obtain an estimate of the total number of sources likely to be present in M31, the Magellanic Clouds, and in our own Galaxy. We find that in M31, where approximately 15 supersoft sources have been identified and roughly an equal number of sources are being investigated as supersoft candidates, there are likely to be approximately 2500 active supersoft sources at the present time. In our own Galaxy, where about four supersoft sources have been detected in the Galactic plane, there are likely to be approximately 1000 active sources. Similarly, with about six and about four (nonforeground) sources observed in the Large (LMC) and Small Magellanic Clouds (SMC), respectively, there should be approximately 30 supersoft sources in the LMC, and approximately 20 in the SMC. The likely uncertainties in the numbers quoted above, and the properties of observable sources relative to those of the total underlying population, are also derived in detail. These results can be scaled to estimate the numbers of supersoft sources likely to be present in other galaxies. The results reported here on the underlying population of supersoft X-ray sources are in good agreement with the results of a prior population synthesis study of the white dwarf accretor model for luminous supersoft X-ray sources. It should be emphasized, however

  19. The derived population of luminous supersoft X-ray sources

    NASA Technical Reports Server (NTRS)

    Di Stefano, R.STEFANO; Rappaport, S.

    1994-01-01

    The existence of a new class of astrophysical object, luminous supersoft X-ray sources, has been established through ROSAT satellite observations and analysis during the past approximately 3 yr. Because most of the radiation emitted by supersoft sources spans a range of wavelengths readily absorbed by interstellar gas, a substantial fraction of these sources may not be detectable with present satellite instrumentation. It is therefore important to derive a reliable estimate of the underlying population, based on the approximately 30 sources that have been observed to date. The work reported here combines the observational results with a theoretical analysis, to obtain an estimate of the total number of sources likely to be present in M31, the Magellanic Clouds, and in our own Galaxy. We find that in M31, where approximately 15 supersoft sources have been identified and roughly an equal number of sources are being investigated as supersoft candidates, there are likely to be approximately 2500 active supersoft sources at the present time. In our own Galaxy, where about four supersoft sources have been detected in the Galactic plane, there are likely to be approximately 1000 active sources. Similarly, with about six and about four (nonforeground) sources observed in the Large (LMC) and Small Magellanic Clouds (SMC), respectively, there should be approximately 30 supersoft sources in the LMC, and approximately 20 in the SMC. The likely uncertainties in the numbers quoted above, and the properties of observable sources relative to those of the total underlying population, are also derived in detail. These results can be scaled to estimate the numbers of supersoft sources likely to be present in other galaxies. The results reported here on the underlying population of supersoft X-ray sources are in good agreement with the results of a prior population synthesis study of the white dwarf accretor model for luminous supersoft X-ray sources. It should be emphasized, however

  20. 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.

  1. 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.

  2. 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.

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

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Jones, B. F.; Walker, H. J.

    1989-01-01

    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.

  4. 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.

  5. 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.

  6. Searching for luminous absorbed sources in the WISE AGN catalogue

    NASA Astrophysics Data System (ADS)

    Mountrichas, G.; Georgantopoulos, I.; Secrest, N. J.; Ordovás-Pascual, I.; Corral, A.; Akylas, A.; Mateos, S.; Carrera, F. J.; Batziou, E.

    2017-07-01

    Mid-infrared (IR) colour selection techniques have proved to be very efficient in finding active galactic nuclei (AGN). This is because the AGN heats the surrounding dust producing warm mid-IR colours. Using the Wide-field Infrared Survey Explorer 3.6, 4.5 and 12 μm colours, the largest sample of IR selected AGN has already been produced containing 1.4 million AGN over the whole sky. Here, we explore the X-ray properties of this AGN sample by cross-correlating it with the subsample of the 3XMM X-ray catalogue that has available X-ray spectra and at the same time optical spectroscopy from Sloan Digital Sky Survey (SDSS). Our goal is to find rare luminous obscured AGN. Our final sample contains 65 QSOs with log νLν ≥ 46.2 erg s-1. This IR luminosity cut corresponds to log LX ≈ 45 erg s-1, at the median redshift of our sample (z = 2.3), that lies at the bright end of the X-ray luminosity function at z > 2. The X-ray spectroscopic analysis reveals seven obscured AGN having a column density NH > 1022 cm-2. Six of them show evidence for broad [C iv] absorption lines and five are classified as broad absorption line QSOs. We fit the optical spectra of our X-ray absorbed sources to estimate the optical reddening. We find that none of these show any obscuration according to the optical continuum. These sources add to the growing evidence for populations of luminous QSOs with evidence for substantial absorption by outflowing ionized material, similar to those expected to be emerging from their absorbing cocoons in the framework of AGN/galaxy co-evolution.

  7. 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.

  8. The warp of the Galactic stellar disk detected in IRAS source counts

    NASA Technical Reports Server (NTRS)

    Djorgovski, S.; Sosin, Craig

    1989-01-01

    About 90,000 IRAS point sources have been used as disk tracers in order to explore the possibility of warp in the Galactic stellar disk. The results imply that the Galactic stellar disk is warped at large radii in a way similar to the H-I layer, and that the warp is an important characteristic of the Galaxy as a whole. It is suggested that the warp may be a long-lasting phenomenon, possibly caused by asymmetries of the mass distribution in the outer regions of the Galactic dark halo.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. The IRAS 08589-4714 star-forming region

    NASA Astrophysics Data System (ADS)

    Saldaño, H. P.; Vasquez, J.; Cappa, C. E.; Gómez, M.; Duronea, N.; Rubio, M.

    2017-04-01

    We present an analysis of the IRAS 08589-4714 star-forming region. This region harbors candidate young stellar objects identified in the WISE and Herschel images using color index criteria and spectral energy distributions (SEDs). The SEDs of some of the infrared sources and the 70 μm radial intensity profile of the brightest source are modeled using the DUSTY code. For these objects, we estimate the main parameters, which suggest that they are very young, massive and luminous objects at early stages of the formation process. We use the emission distribution in the infrared at 70 and 160 μm to estimate the dust temperature gradient. This suggests that the nearby massive starforming region RCW 38, located at ≈10 pc from the IRAS source position, may be contributing to the photodissociation of the molecular gas and to the heating of the interstellar dust in the environs of the IRAS source.

  15. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 3: The point source catalog declination range 30 deg greater than delta greater than 0 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 3, The Point Source Catalog Declination Range 30 deg greater than delta greater than 0 deg.

  16. 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.

  17. 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.

  18. Accretion disk spectra of the ultra-luminous compact X-ray sources in nearby spiral galaxies and the super-luminal jet sources

    NASA Astrophysics Data System (ADS)

    Ebisawa, Ken; Kubota, Aya; Mizuno, Tsunefumi; Zycki, Piotr

    2001-09-01

    The Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and the Galactic super-luminal jet sources share the common spectral characteristic that they have extremely high disk temperatures which cannot be explained in the framework of the standard accretion disk model in the Schwarzschild metric. We examine several possibilities to solve this "too-hot" disk problem. In particular, we have calculated an extreme Kerr disk model to fit the observed spectra. We found that the Kerr disk will become significantly harder compared to the Schwarzschild disk only when the disk is highly inclined. For super-luminal jet sources, which are known to be inclined systems, the Kerr disk model may work if we choose proper values for the black hole angular momentum. For the ULXs, however, the Kerr disk interpretation will be problematic, as it is highly unlikely that their accretion disks are preferentially inclined.

  19. The experimental determination of the luminous flux emitted by a few types of lighting sources

    NASA Astrophysics Data System (ADS)

    Spunei, E.; Piroi, I.; Chioncel, C. P.

    2017-01-01

    This paper aims to determine the luminous flux of several types of power sources used for the artificial lighting inside. The luminous flux was determined using a photometer integrator (lumenmeter Ulbricht) and a luxmeter from the laboratory of Electrical and Lighting University “Eftimie Murgu” Resita. Based on a reference source, the constant of the integrator photometer k was determined. The paper presents the measuring results of the luminous flux on several lighting sources: with incandescent, fluorescent, and LED. It has been found that the amount of luminous flux in the nominal data written in the box of lighting sources, does not correspond to the actual measured value. Using the photometric sphere, the actual light output from various sources were it is not known, can be determined.

  20. Detection of spectral variability of the optical component of the IR source IRAS 20508+2011

    NASA Astrophysics Data System (ADS)

    Klochkova, V. G.; Panchuk, V. E.; Tavolzhanskaya, N. S.; Zhao, G.

    2006-03-01

    Our high-resolution spectral observations have revealed variability of the optical spectrum of the cool star identified with the IR source IRAS 20508+2011. We measured the equivalent widths of numerous absorption lines of neutral atoms and ions at wavelengths 4300 7930 Å, along with the corresponding radial velocities. Over the four years of our observations, the radial velocity derived from photospheric absorption lines varied in the interval V r⊙ = 15 30 km/s. In the same period, the Hα profile varied from being an intense bell-shaped emission line with a small amount of core absorption to displaying two-peaked emission with a central absorption feature below the continuum level. At all but one epoch, the positions of the metallic photospheric lines were systematically shifted relative to the Hα emission: ΔV r = V r(met) - V r(Hα, emis) ≈ -23 km/s. The Na D doublet displayed a complex profile with broad (half-width ≈ 120 km/s) emission and photospheric absorption, as well as an interstellar component. We used model atmospheres to determine the physical parameters and chemical composition of the star’s atmosphere: T eff = 4800 K, log g = 1.5, ξt = 4.0 km/s. The metallicity of the star differs little from the solar value: [Fe/H]⊙ = -0.36. We detected overabundances of oxygen [O/Fe]⊙ = +1.79 (with the ratio [C/O] ≈ -0.9), and α-process elements, as well as a deficit of heavy metals. The entire set of the star’s parameters suggests that the optical component of IRAS 20508+2011 is an “O-rich” AGB star with luminosity M v ≈ -3m that is close to its evolutionary transition to the post-AGB stage.

  1. A study of the evolutionary stages of IRAS sources and outflows in the Mon OB1 dark cloud

    NASA Technical Reports Server (NTRS)

    Wolf-Chase, G.; Davidson, J.

    1997-01-01

    An ongoing project aiming to relate the evolutionary stages of the Infrared Astronomy Satellite (IRAS) sources in the Mon OB1 dark cloud to the morphology and energetics of outflows associated with some of these sources, is reported on. Previous evolutionary classifications of IRAS sources are refined and potential class O objects are identified. The fully-sampled CO maps of the outflows in this cloud are presented. These observations yield information on outflow structure, kinematics and excitation conditions. Low-intensity, high velocity gas is observed in the youngest outflows. This emission is characterized by relatively flat line wings at the highest velocities in spectral line profiles obtained at the peaks of the outflow emission.

  2. Bow shocks in a newly discovered maser source in IRAS 20231+3440

    NASA Astrophysics Data System (ADS)

    Ogbodo, C. S.; Burns, R. A.; Handa, T.; Omodaka, T.; Nakagawa, A.; Nagayama, T.; Honma, M.; Chibueze, J. O.; Ubachukwu, A. A.; Eze, R. N. C.

    2017-08-01

    From measuring the annual parallax of water masers over 1.5 yr with VLBI Exploration of Radio Astrometry, we present the trigonometric parallax and corresponding distance of another newly identified water maser source in the region of IRAS 20231+3440 as π = 0.611 ± 0.022 mas and D = 1.64 ± 0.06 kpc, respectively. We measured the absolute proper motions of all the newly detected maser spots (30 spots) and presented two pictures describing the possible spatial distribution of the water maser as the morphology marks out an arc of masers whose average proper motion velocity in the jet direction was 14.26 km s-1. As revealed by the ALLWISE composite image and by applying the colour-colour method of young stellar objects (YSO) identification and classification on photometric archived data, we identified the driving source of the north maser group to be a class I, young stellar object. To further probe the nature of the progenitor, we used the momentum rate maximum value (1.2 × 10-4 M⊙ yr-1 km s-1) of the outflow to satisfy that the progenitor under investigation is a low-mass young stellar object concurrently forming alongside an intermediate-mass YSO ˜60 000 au (˜37 arcsec) away from it.

  3. Focal waveforms for various source waveforms driving a prolate-spheroidal impulse radiating antenna (IRA)

    NASA Astrophysics Data System (ADS)

    Altunc, Serhat; Baum, Carl E.; Christodoulou, Christos G.; Schamiloglu, Edl; Buchenauer, C. Jerald

    2008-08-01

    Impulse radiating antennas (IRAs) are designed to radiate very fast pulses in a narrow beam with low dispersion and high field amplitude. For this reason they have been used in a variety of applications. IRAs have been developed for use in the transient far-field region using parabolic reflectors. However, in this paper we focus in the near field region and develop the field waveform at the second focus of a prolate-spheroidal IRA. Certain skin cancers can be killed by the application of a high-amplitude electric field pulse. This can be accomplished by either inserting electrodes near the skin cancer or by applying fast, high-electric field pulses without direct contact. We investigate a new manifestation of an IRA, in which we use a prolate spheroid as a reflector instead of a parabolic reflector and focus in the near-field region instead of the far-field region. This technique minimizes skin damage associated with inserting electrodes near the tumor. Analytical and experimental behaviors for the focal waveforms of two and four-feed arm prolate-spheroidal IRAs are explored. With appropriate choice of the driving waveform we maximize the impulse field at the second focus. The focal waveform of a prolate-spheroidal IRA has been explained theoretically and verified experimentally.

  4. 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.

  5. 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.

  6. Infrared Astronomy After IRAS.

    PubMed

    Rieke, G H; Werner, M W; Thompson, R I; Becklin, E E; Hoffmann, W F; Houck, J R; Low, F J; Stein, W A; Witteborn, F C

    1986-02-21

    The 250,000 sources in the recently issued Infrared Astronomy Satellite (IRAS) all-sky infrared catalog are a challenge to astronomy. Many of these sources will be studied with existing and planned ground-based and airborne telescopes, but many others can no longer even be detected now that IRAS has ceased to operate. As anticipated by advisory panels of the National Academy of Sciences for a decade, study of the IRAS sources will require the Space Infrared Telescope Facility (SIRTF), a cooled, pointed telescope in space. This instrument may be the key to our understanding of cosmic birth-the formation of planets, stars, galaxies, active galactic nuclei, and quasars. Compared with IRAS and existing telescopes, SIRTF's power derives from a thousandfold gain in sensitivity over five octaves of the spectrum.

  7. EXPLORATION OF A RELIC CIRCUMSTELLAR ENVELOPE IN THE ''WATER FOUNTAIN'' SOURCE IRAS 18286-0959

    SciTech Connect

    Imai, Hiroshi; Nakashima, Jun-ichi; Yung, Bosco H. K.; Kwok, Sun; Deguchi, Shuji; Diamond, Philip J. E-mail: junichi@hku.hk E-mail: sunkwok@hku.hk E-mail: diamond@skatelescope.org

    2013-07-01

    The water fountain source IRAS 18286-0959 (I18286) was reported as an object exhibiting highly collimated, double-helix stellar jets traced by the H{sub 2}O maser emission. Using the European VLBI Network, we measured the absolute coordinates of the 1612 MHz OH maser emission in I18286, which is very likely associated with a relic of a circumstellar envelope (CSE) developed in the asymptotic giant branch stage of the central star. The location of the OH maser is near the center of the H{sub 2}O maser feature cluster, where one of the originating points of the two jets is located. We also mapped 22.2 GHz H{sub 2}O maser emission in this object using the Very Long Baseline Array in the seasons of 2006-2007 as well as 2008-2009. In the first three epochs in 2006-2007, we detected at least 90 maser features per epoch. In six epochs in 2008-2009, when the observation data had already been published and analyzed to identify the double-helix jets, we newly identified 14 proper motions of H{sub 2}O maser features which could not be measured in the previous analysis due to their short lifetimes. In this paper, together with the OH maser emission, we focus on ''outlier'' H{sub 2}O maser features, which exhibit slow expansion velocities (V{sub exp} {approx}< 30 km s{sup -1}) and are likely associated with either the relic CSE or an equatorial flow of I18286. They were marginally distinguishable from the maser features associated with the jets in I18286.

  8. 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.

  9. 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.

  10. 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.

  11. A search for T Tauri stars in high-latitude molecular clouds. I. IRAS sources and CCD imaging

    SciTech Connect

    Magnani, L.; Caillault, J.; Armus, L. E. O. Hulburt Center for Space Research, Washington, DC Georgia Univ., Athens Maryland Univ., College Park )

    1990-07-01

    Results are reported from a search for excess H-alpha emission from point sources in 19 high-Galactic-latitude molecular clouds (two dark clouds and 17 translucent clouds). A total of 111 candidate sources from the IRAS Point Source Catalog were evaluated, but most of these (except for five T Tau stars in the dark clouds) were found to be 100-micron cirrus sources, galaxies, or field stars. CCD observations of 23 ambiguous sources were obtained in the red and H-alpha bands using a CCD detector on the 0.9-m telescope at KPNO during September 1987 and February 1988: no H-alpha/R ratios more than 5 sigma above the respective field averages were found. It is concluded that significant low-mass star formation in translucent high-latitude molecular clouds is unlikely. 30 refs.

  12. 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.

  13. The optical counterpart of IRAS 12496 - 7650 - A highly embedded Herbig AE star

    NASA Astrophysics Data System (ADS)

    Hughes, J. D.; Hartigan, P.; Graham, J. A.; Emerson, J. P.; Marang, F.

    1991-03-01

    Optical and near-infrared observations of IRAS 12496 - 7650, an active young star and the most luminous IRAS source in the Chamaeleon II dark cloud, are reported. The object has become brighter at optical wavelengths since 1976, and has exhibited variations of more than a magnitude at K between January 1987 and May 1990. IRAS 12496 - 7650 is redder when fainter, and the amplitude of the brightness fluctuations decreases toward longer infrared wavelengths. Differing amounts of circumstellar extinction or intrinsic color variations of the source can produce most of the observed variability. Optical spectra confirm that IRAS 12496 - 7650 is an extremely active (probably Herbig Ae type) star with blueshifted forbidden lines of O I and S II and a prominent P-Cygni profile at H-alpha. The S II emission extends 3-4 arcsec on either side of the star and shows a significant velocity gradient, suggestive of a jetlike structure. The detection of outflowing material from IRAS 12496 - 7650 reinforces earlier evidence that this object is the exciting source for the HH 52 - 54 group Herbig-Haro objects. The broad spectral energy distribution suggests that IRAS 12496 - 7650 has a circumstellar disk.

  14. 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.

  15. 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.

  16. 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.

  17. Interstellar and circumstellar medium in the direction to IR source IRAS 01005+7910

    NASA Astrophysics Data System (ADS)

    Sendzikas, E. G.

    2016-01-01

    Using the high-resolution spectra obtained at the 6-meter telescope of the SAO RAS over 2002-2013, we studied the spectral features of the lines of interstellar medium. The radial velocities of the Na I 5890 Å, Na I 5896 Å, Ca II 3934 Å and Ca II 3968 Å absorption lines were analyzed. Seven diffuse interstellar bands 4964, 5780, 5797, 6196, 6203, 6379 Å were identified in the optical spectrum of IRAS01005+7910. Radial velocities V r and equivalent widths W λ of these DIBs were measured, for which the values of the interstellar reddening E B-V and column density of neutral hydrogen log [N(H)] were calculated.

  18. IRAS observations of comets

    NASA Technical Reports Server (NTRS)

    Walker, R. G.; Matson, D. L.; Veeder, G. J.

    1986-01-01

    The moderate spatial resolution and high sensitivity of the Infrared Astronomical Satellite (IRAS), which surveyed the celestial sphere during 1983 at wavelengths of 12, 25, 60, and 100 microns, were particularly well suited to detecting extended thermal emission from cometary dust. Sources with infrared color temperatures characteristic of solar system bodies, and at the ephemerides position of known comets were selected for analysis by the IRAS Asteroid Data Analysis System (ADAS). The data base is now available for use by researchers. This paper describes the development of the data base, details its entries, and presents a statistical analysis of its contents. The IRAS survey contains multiple observations of many periodic comets. A brief description and analysis is given of the observed infrared and derived physical properties for several comets of special interest.

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

    NASA Technical Reports Server (NTRS)

    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.

  20. 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.

  1. New Eruptive Variable in the Massive Star-Forming Region Associated with IRAS 18507+0121 Source

    NASA Astrophysics Data System (ADS)

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

    2017-07-01

    We report the discovery of a strong outburst of the embedded young stellar object (YSO), namely UKIDSS-J185318.36+012454.5, located in the star-forming region associated with IRAS 18507+0121 source and GAL 034.4+00.23 HII region. According to the near and mid-infrared colors and spectral energy distribution (SED), we classify the object as an intermediate mass young stellar object (YSO) with Class 0/I evolution stage. The outburst occurred in the period of 2004-2006. The amplitude of brightness is at least Ks = 5.0 mag. The summation of the photometric and spectral data does not allow to classify UKIDSS-J185318.36+012454.5 as FUor or EXor. We can consider it as an eruptive variable with mixed characteristics or MNor type object.

  2. Tianma 65-m telescope detection of new OH maser features towards the water fountain source IRAS 18286-0959

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Shen, Zhi-Qiang; Li, Xiao-Qiong; Yang, Kai; Nakashima, Jun-ichi; Wu, Ya-Jun; Zhao, Rong-Bin; Li, Juan; Wang, Jun-Zhi; Jiang, Dong-Rong; Wang, Jin-Qing; Li, Bin; Zhong, Wei-Ye; Yung, Bosco H. K.

    2017-07-01

    We report the results of the OH maser observation towards the water fountain source IRAS 18286-0959 using the newly built Shanghai Tianma 65-m Radio Telescope. We observed the three OH ground state transition lines at frequencies of 1612, 1665 and 1667 MHz. Comparing with the spectra of previous observations, we find new maser spectral components at velocity channels largely shifted from the systemic velocity: the velocity offsets of the newly found components lie in the range 20-40 km s-1 with respect to the systemic velocity. Besides maser variability, another possible interpretation for the newly detected maser features is that part of the molecular gas in the circumstellar envelope is accelerated. The acceleration is probably caused by the passage of a high-velocity molecular jet, which has been detected in previous Very Long Baseline Interferometry observations in the H2O maser line.

  3. The Visibility of Point Sources as a Function of Background Luminance, Target Luminance, Eccentricity, Wavelength, and Flicker Rate

    DTIC Science & Technology

    2005-10-01

    the German scientist, Ernst Heinrich Weber (1795-1878), states that the increase in stimulus which is necessary to produce a just noticeable...thresholds at 60° eccentricity. 3 predict thresholds in the Weber range. Its threshold predictions as a function of eccentricity are based on...such as VIDEM that assume a constant Weber fraction tend to underestimate visual thresholds at low ambient luminances and overestimate them at

  4. IRAS: Taking inventory

    NASA Astrophysics Data System (ADS)

    Reichhardt, Tony

    Even though its active life has ended, the Infrared Astronomical Satellite (IRAS) continues to make new discoveries as scientists at the Jet Propulsion Laboratory in Pasadena, Calif., pore over data from the orbiting satellite's year-long survey of the infrared universe. IRAS ran out of the cryogenic fluid that kept its telescope and detectors cold enough for sensitive, infrared observations last November, thus ending the survey phase of the international project. Now begins the detailed study of IRAS data and the preparation of maps and catalogues of all infrared sources found by the satellite for distribution to the scientific community.Among the discoveries already credited to IRAS are a ring of solid particles, possibly an evolving solar system, around the bright star Vega; six previously unknown comets; three narrow rings of dust lying within the plane of the solar system that may be the remains of asteroid or comet collisions; a small body designated 1983 TB that appears to be the burned-out cometary source of the annual Geminid meteor shower, and which passes closer to the sun at its perihelion than any planet or known asteroid; and many new and fascinating stellar and galactic sources.

  5. 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.

  6. Molecular clouds associated with luminous far-infrared sources in the outer Galaxy

    NASA Technical Reports Server (NTRS)

    Carpenter, John M.; Snell, Ronald L.; Schloerb, F. Peter

    1990-01-01

    The stellar content and physical properties of the molecular clouds associated with 21 bright far-IR sources in the outer Galaxy have been determined through C-12O, C-13O, 6-cm radio continuum, and IRAS observations. The molecular cloud masses range from 200 to about 10,000 solar masses. The far-IR luminosity-to-mass ratio for these clouds has a mean value of 6.8 solar luminosity/solar masses and shows no correlation with the cloud mass, a result similar to that found for more massive clouds in the inner Galaxy. The radio continuum survey of the 21 bright far-IR sources indicates that most of these regions probably have a single, massive star providing most of the ionization. The cloud masses derived from virial and LTE analyses are in agreement, supporting the assumptions commonly made in their calculations, and a tight, near-linear correlation is found between the C-12O luminosity and the cloud mass. The H2 column density and integrated C-12O intensity are also correlated on a point-by-point basis, although the scatter is larger than the C-12O luminosity-cloud mass relation.

  7. On the black hole masses in ultra-luminous X-ray sources

    NASA Astrophysics Data System (ADS)

    Zhou, Xin-Lin

    2015-05-01

    Ultra-luminous X-ray sources (ULXs) are off-nuclear X-ray sources in nearby galaxies with X-ray luminosities ⩾ 1039 erg s-1. The measurement of the black hole (BH) masses of ULXs is a long-standing problem. Here we estimate BH masses in a sample of ULXs with XMM-Newton observations using two different mass indicators, the X-ray photon index and X-ray variability amplitude based on the correlations established for active galactic nuclei (AGNs). The BH masses estimated from the two methods are compared and discussed. We find that some extreme high-luminosity (LX > 5 ×1040 erg s-1) ULXs contain the BH of 104-105 M⊙ . The results from X-ray variability amplitude are in conflict with those from X-ray photon indices for ULXs with lower luminosities. This suggests that these ULXs generally accrete at rates different from those of X-ray luminous AGNs, or they have different power spectral densities of X-ray variability. We conclude that most of ULXs accrete at super-Eddington rate, thus harbor stellar-mass BH.

  8. 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.

  9. 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.

  10. 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.

  11. IRAS 23385+6053: AN Example of Candidate Massive Protostar

    NASA Astrophysics Data System (ADS)

    Fontani, Francesco; Cesaroni, Riccardo; Testi, Leonardo; Walmsley, Malcolm

    We present the results of a multi-line study towards the source IRAS 23385+6053 performed with the IRAM-30m telescope the Plateau de Bure Interferometer and the Very Large Array. We have obtained single-dish and interferometric maps in various transitions of the C18O C17O CH3CCH and NH3 molecular species. Our results confirm the findings of Molinari et al. (1998b) namely that IRAS 23385 a luminous (and therefore massive) source (L ~ 1.6 x 104 solar luminosities) is a good candidate high-mass class 0 object precursor of an ultracompact HII region. The source is approximately made out of two components: a compact molecular ~2 arcsec core with temperature of ~40 K and an H2 volume density of the order of 107 cm-3 and a more extended clump (~15 arcsec) with an average kinetic temperature of ~15 K and H2 volume density of the order of 105 cm-3. The core temperature is much smaller than typical temperatures found in hot molecular cores around massive ZAMS stars. This result supports the idea that IRAS 23385 is a massive protostar in a pre-ZAMS evolutionary stage still accreting material from its parental molecular cloud and deriving most of its luminosity from the release of gravitational energy.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Ultra-Luminous X-ray Sources in the Collisional Ring Galaxy NGC 922

    NASA Astrophysics Data System (ADS)

    Prestwich, Andrea H.; Galache, J.; Kalogara, V.; Linden, T.; Kilgard, R.; Zezas, A.; Wolter, A.; Trinchieri, G.

    2010-01-01

    We present a new Chandra observation of the nearby collisional ring galaxy NGC 922. NGC 922 is undergoing a violent burst of star formation as density waves are driven through the disk as a result of the collision. It is similar to the famous Cartwheel galaxy, except that the metallicity is somewhat higher and star formation rate lower. Our primary science goal is to determine whether a low metallicty environment is required to form the most luminous X-ray sources (Lx>1E40 ergs s-1). We find a total of 14 bright X-ray sources, 7 of which are ULX ((Lx>1E39 ergs s-1). One source has Lx 1E40 ergs/s. The X-ray sources are associated with the H-alpha ring. However, they are NOT associated with the brightest H-alpha patches, suggesting that the ULX phase starts >1 x 1E7 years after the starburst. Like the Cartwheel, the X-ray luminosity function of NGC 922 has a slope close to that of the “cannonical” HMXB slope of Gilfanov et al 2004. We conclude that NGC 922 is forming ULX as efficiently as the Cartwheel (after allowing for the difference in the star formation rate). We do not see a strong metallicity effect.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Observation of the HH 1 and 2 region with IRAS

    NASA Technical Reports Server (NTRS)

    Pravdo, Steven H.; Chester, Thomas J.

    1987-01-01

    Infrared Astronomical Satellite (IRAS) observations of the region in Orion containing HH 1 and 2 reveal for the first time the large-scale distribution of newly formed stars. New infrared sources discovered in these observations are discussed, and attempts are made to untangle the complex infrared morphology of this field. A major finding of this study is that HH 1 is near the peak of an intense and broad plateau of 60 and 100 micron emission that spatially corresponds well with the boundaries of a previously detected molecular cloud. Other findings include the detection of an emitting circum-HH object dust complex around HH 2, 25 micron emission associated with the putative HH 1 and 2 exciting source discovered with the VLA, a new luminous far-infrared source, and numerous infrared source complexes, some in blank optical fields and others in fields containing optical emission-line stars.

  2. Observation of the HH 1 and 2 region with IRAS

    NASA Technical Reports Server (NTRS)

    Pravdo, Steven H.; Chester, Thomas J.

    1987-01-01

    Infrared Astronomical Satellite (IRAS) observations of the region in Orion containing HH 1 and 2 reveal for the first time the large-scale distribution of newly formed stars. New infrared sources discovered in these observations are discussed, and attempts are made to untangle the complex infrared morphology of this field. A major finding of this study is that HH 1 is near the peak of an intense and broad plateau of 60 and 100 micron emission that spatially corresponds well with the boundaries of a previously detected molecular cloud. Other findings include the detection of an emitting circum-HH object dust complex around HH 2, 25 micron emission associated with the putative HH 1 and 2 exciting source discovered with the VLA, a new luminous far-infrared source, and numerous infrared source complexes, some in blank optical fields and others in fields containing optical emission-line stars.

  3. 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.

  4. 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.

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

    SciTech Connect

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

    1988-02-05

    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% of its energy at far-infrared wavelengths. IRAS 14348-1447, which is receding from the sun at 8% 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 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. The derived mass of interstellar molecular hydrogen is 6 {times} 10{sup 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.

  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

    1988-02-05

    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.

  7. A deficit of ultraluminous X-ray sources in luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Luangtip, W.; Roberts, T.; Mineo, S.; Lehmer, B.; Alexander, D.

    2014-07-01

    Luminous infrared galaxies (LIRGs) are amongst the most energetic star-forming galaxies, producing total infrared luminosities > 10^{11} L_{⊙} that imply star formation rates (SFR) in excess of 10 M_{⊙} yr^{-1}. Given the close relationship between the number of ultraluminous X-ray sources (ULXs) and SFR, we might therefore expect to find larger populations of ULXs in LIRGs than in field galaxies. Here, we present the results of a study of the ULX population in 17 nearby (D < 60 Mpc) LIRGs, using Chandra data. Only 53 ULXs have been detected, compared to an expectation of ˜500 ULXs from studies of field galaxies (Swartz et al. 2011). We investigate the origin of this large deficit in the number of ULXs by several means. For instance, X-ray luminosity functions confirm the deficit and also reveal a possible break at a luminosity of ˜2×10^{39} erg s^{-1}. The physical interpretation for the deficit will be discussed. In addition, a study of the evolution of the ULX spectra with luminosity based on stacked X-ray spectra shows a possible transition from ˜Eddington to super-Eddington states, consistent with the ULXs being a population of ˜10 solar mass black holes.

  8. Optical integral field spectroscopy and ROSAT X-ray imaging of IRAS 09104+4109

    NASA Astrophysics Data System (ADS)

    Crawford, C. S.; Vanderriest, C.

    1996-12-01

    We present results from a long observation using the integral field spectrograph ARGUS of the ultraluminous IRAS source IRAS 09104+4109, which is associated with the central galaxy of a rich cluster at a redshift z=0.44. We map the distribution, kinematics and ionization state of its extended emission-line region, and show that both the nucleus and a secondary peak of line emission have ratios consistent with photoionization by a hidden, but luminous, quasar continuum. The kinematics of the ionized gas suggests that the galaxy and its extended emission-line region form a relatively static system at the cluster core. A strongly blueshifted component of emission-line gas around the nucleus reveals a central outflow, due either to a change in the central radio source, or to a massive supernova wind. We also present a ~30-ks ROSAT HRI pointed observation of IRAS 09104+4109. The X-ray image is extended, and a deprojection analysis confirms the presence of a 800-1100 M_solar yr^-1 cooling flow in the L_X=2.9x10^45 erg s^-1 cluster. A central dip is observed in the X-ray image, which may be caused by the outflow seen in the optical data. IRAS 09104+4109 is probably a very highly absorbed quasar, and presents the firmest case for a strong cooling flow occurring around a quasar, and the first to be discovered directly from an X-ray image.

  9. 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.

  10. 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.

  11. Radio-Excess IRAS Galaxies. II. Host Galaxies

    NASA Astrophysics Data System (ADS)

    Drake, Catherine L.; McGregor, Peter J.; Dopita, Michael A.

    2004-09-01

    This is the second of a series of papers studying a sample of radio-excess IRAS galaxies. These galaxies have radio emission in excess of that expected due to star formation, but largely fall between the traditional categories of radio-loud and radio-quiet active galaxies. R-band images of the hosts of far-infrared (FIR)-luminous radio-excess galaxies are presented and analyzed. The hosts of the FIR-luminous radio-excess galaxies are luminous galaxies, on average 0.8 mag brighter than M*R. Their optical luminosities and morphologies are similar to comparison samples of radio-loud compact steep-spectrum and gigahertz peaked-spectrum sources and extended radio galaxies. We find a similar fraction of galaxies in our sample (~70%) with companions or distorted morphologies as in radio-loud comparison samples. This is consistent with radio activity being associated with tidal interaction. The majority (65%) of the FIR-luminous radio-excess galaxies have radio source sizes that are smaller than the optical host by more than an order of magnitude. These compact radio sources may be young precursors to classical radio galaxies or a different population of radio sources, possibly confined by the host interstellar medium. The host galaxy types were determined by analysis of the surface brightness distributions. The elliptical hosts have effective surface brightnesses and radii consistent with known ellipticals but inconsistent with a population of brightest cluster galaxies. Thus, it is unlikely these objects are the precursors of FR I radio galaxies. The disk hosts have smaller sizes and low radio excesses. However, they have a range of radio source sizes, which is not expected if they are radio-``loud'' Seyfert galaxies.

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

    NASA Astrophysics Data System (ADS)

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

    1995-12-01

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

  13. Opto-thermal study of cooling strategies for high-luminance white-light solid-state sources

    NASA Astrophysics Data System (ADS)

    Correia, António; Hanselaer, Peter; Meuret, Youri

    2016-06-01

    Solid-state sources have become ubiquitous is many lighting applications. For general lighting, phosphors are typically employed to produce white light from the narrowband light emitted from solid-state sources. As the optical output power from solid-state sources keeps increasing, increasingly higher luminance can be obtained, which, unfortunately, also increases the phosphor's temperature. These materials' colour conversion potential, encoded by the quantum yield, has complex dependencies with temperature. To obtain an accurate assessment of the performance of a high-luminance white light source configuration based on individual solid-state sources, it is imperative to accurately model the temperature distribution inside the phosphor material and consider the effect of temperature on the quantum yield of the phosphor. In addition, the feedback of the varying quantum yield on the generated heat inside the phosphor should also be considered. An opto-thermal framework has been previously proposed to accurately simulate the opto-thermal effects in phosphors when designing lighting systems. In this paper, this framework is applied to a novel optical configuration to investigate thermal bottlenecks and test cooling strategies to avoid them. For the specific configuration tested, using an active cooling strategy and concentrating the laser light on the phosphor region with the best thermal dissipation proved to be the best solutions.

  14. THE X-RAY SPECTRA OF THE LUMINOUS LMXBs IN NGC 3379: FIELD AND GLOBULAR CLUSTER SOURCES

    SciTech Connect

    Brassington, N. J.; Fabbiano, G.; Zezas, A.; Kim, D.-W.; Blake, S.; Angelini, L.; Davies, R. L.; Gallagher, J.; Kalogera, V.; King, A. R.; Kundu, A.; Zepf, S.; Trinchieri, G.

    2010-12-20

    From a deep multi-epoch Chandra observation of the elliptical galaxy NGC 3379 we report the spectral properties of eight luminous LMXBs (L{sub X} >1.2 x 10{sup 38} erg s{sup -1}). We also present a set of spectral simulations, produced to aid the interpretation of low-count single-component spectral modeling. These simulations demonstrate that it is possible to infer the spectral states of X-ray binaries from these simple models and thereby constrain the properties of the source. Of the eight LMXBs studied, three reside within globular clusters (GCs) and one is a confirmed field source. Due to the nature of the luminosity cut, all sources are either neutron star (NS) binaries emitting at or above the Eddington luminosity or black hole (BH) binaries. The spectra from these sources are well described by single-component models, with parameters consistent with Galactic LMXB observations, where hard-state sources have a range in photon index of 1.5-1.9 and thermally dominant (TD) sources have inner-disk temperatures between {approx}0.7and1.55 keV. The large variability observed in the brightest GC source (L{sub X} >4 x 10{sup 38} erg s{sup -1}) suggests the presence of a BH binary. At its most luminous this source is observed in a TD state with kT{sub in} = 1.5 keV, consistent with a BH mass of {approx}4 M{sub sun}. This observation provides further evidence that GCs are able to retain such massive binaries. We also observed a source transitioning from a bright state (L{sub X} {approx}1 x 10{sup 39} erg s{sup -1}), with prominent thermal and non-thermal components, to a less luminous hard state (L{sub X} = 3.8 x 10{sup 38} erg s{sup -1}, {Gamma}= 1.85). In its high flux emission, this source exhibits a cool-disk component of {approx}0.14 keV, similar to spectra observed in some ultraluminous X-ray sources (ULXs). Such a similarity indicates a possible link between 'normal' stellar-mass BHs in a high accretion state and ULXs.

  15. IRAS observations of AGN candidates at low flux levels

    NASA Technical Reports Server (NTRS)

    Degrijp, Marinus H. K.; Keel, William C.; Miley, George K.

    1987-01-01

    IRAS additional observations were used to obtain a sample of point sources at much fainter flux levels than hitherto available through the IRAS Point Source Catalogue. This sample is being used to compile an incomplete but representative catalogue of faint IRAS candidate Active Galactic Nuclei (AGNs) and to study the evolution of the infrared bright galaxies. Ground based follow up observations (optical spectroscopy) are mainly hampered by identification confusion.

  16. SPITZER IRS SPECTRA OF LUMINOUS 8 {mu}m SOURCES IN THE LARGE MAGELLANIC CLOUD: TESTING COLOR-BASED CLASSIFICATIONS

    SciTech Connect

    Buchanan, Catherine L.; Kastner, Joel H.; Hrivnak, Bruce J.; Sahai, Raghvendra

    2009-12-15

    We present archival Spitzer Infrared Spectrograph (IRS) spectra of 19 luminous 8 {mu}m selected sources in the Large Magellanic Cloud (LMC). The object classes derived from these spectra and from an additional 24 spectra in the literature are compared with classifications based on Two Micron All Sky Survey (2MASS)/MSX (J, H, K, and 8 {mu}m) colors in order to test the 'JHK8' (Kastner et al.) classification scheme. The IRS spectra confirm the classifications of 22 of the 31 sources that can be classified under the JHK8 system. The spectroscopic classification of 12 objects that were unclassifiable in the JHK8 scheme allow us to characterize regions of the color-color diagrams that previously lacked spectroscopic verification, enabling refinements to the JHK8 classification system. The results of these new classifications are consistent with previous results concerning the identification of the most infrared-luminous objects in the LMC. In particular, while the IRS spectra reveal several new examples of asymptotic giant branch (AGB) stars with O-rich envelopes, such objects are still far outnumbered by carbon stars (C-rich AGB stars). We show that Spitzer IRAC/MIPS color-color diagrams provide improved discrimination between red supergiants and oxygen-rich and carbon-rich AGB stars relative to those based on 2MASS/MSX colors. These diagrams will enable the most luminous IR sources in Local Group galaxies to be classified with high confidence based on their Spitzer colors. Such characterizations of stellar populations will continue to be possible during Spitzer's warm mission through the use of IRAC [3.6]-[4.5] and 2MASS colors.

  17. 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.

  18. 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

  19. IRAS known asteroid prediction and association

    NASA Technical Reports Server (NTRS)

    Kia, Tooraj; Fowler, John W.

    1987-01-01

    Techniques and procedures employed to obtain data concerning the known asteroids from IRAS observations are discussed. The IRAS observations covered 95 percent of the sky with at least four scans of the telescope field of view. A search was first carried out for geometrical intersections of the trajectories of a given asteroid and the telescope boresight, following which a matched sighting was sought for each such intersection among the actual IRAS point source detections. By using ground based measurements of visual magnitudes, IRAS observations of IR brightness, and a thermal model, albedos and diameters have been computed for 1,822 known asteroids, increasing the amount of this kind of information by about an order of magnitude.

  20. ON THE IONIZATION OF LUMINOUS WMAP SOURCES IN THE GALAXY: CONSTRAINTS FROM He RECOMBINATION LINE OBSERVATIONS WITH THE GBT

    SciTech Connect

    Roshi, D. Anish; Plunkett, Adele; Rosero, Viviana; Vaddi, Sravani E-mail: adele.plunkett@yale.edu E-mail: sxv1249@rit.edu

    2012-04-10

    Murray and Raham used the Wilkinson Microwave Anisotropy Probe (WMAP) free-free foreground emission map to identify diffuse ionized regions (DIRs) in the Galaxy. It has been found that the 18 most luminous WMAP sources produce more than half of the total ionizing luminosity of the Galaxy. We observed radio recombination lines (RRLs) toward the luminous WMAP source G49.75-0.45 with the Green Bank Telescope near 1.4 GHz. Hydrogen RRL is detected toward the source but no helium line is detected, implying that n{sub He{sup +}}/n{sub H{sup +}}< 0.024. This limit puts severe constraint on the ionizing spectrum. The total ionizing luminosity of G49 (3.05 Multiplication-Sign 10{sup 51} s{sup -1}) is {approx}2.8 times the luminosity of all radio H II regions within this DIR and this is generally the case for other WMAP sources. Murray and Rahman propose that the additional ionization is due to massive clusters ({approx}7.5 Multiplication-Sign 10{sup 3} M{sub Sun} for G49) embedded in the WMAP sources. Such clusters should produce enough photons with energy {>=}24.6 eV to fully ionize helium in the DIR. Our observations rule out a simple model with G49 ionized by a massive cluster. We also considered 'leaky' H II region models for the ionization of the DIR, suggested by Lockman and Anantharamaiah, but these models also cannot explain our observations. We estimate that the helium ionizing photons need to be attenuated by {approx}>10 times to explain the observations. If selective absorption of He ionizing photons by dust is causing this additional attenuation, then the ratio of dust absorption cross sections for He and H ionizing photons should be {approx}>6.

  1. Integral field spectroscopy of IRAS 18276-1431 and IRAS 16342-3814

    NASA Astrophysics Data System (ADS)

    Gledhill, T. M.; Forde, K. P.

    We use integral field spectroscopy to detect the K-band ro-vibrational emission lines of H_2 in IRAS 18276-1431 and IRAS 16342-3814, two post-AGB objects associated with collimated outflows. In IRAS 18276 the H_2 emission arises in shocks within dense, clumpy material in the cavity walls, whereas in IRAS 16342 the emission is seen at the lobe tips and appears to be tracing the working surface of a fast outflow. In both objects we detect the CO bandheads and Na I doublet in emission suggesting hot, low-ionization gas close to the source. These features are also seen in pre-main sequence jet sources and we draw parallels between the two classes of object.

  2. Observations of IRAS F10214+4724 at the Nobeyama millimeter array

    NASA Technical Reports Server (NTRS)

    Sakamoto, K.; Ishizuki, S.; Kawabe, R.; Ishiguro, M.

    1993-01-01

    F10214+4724 is an IRAS source at z=2.286 with L(sub FIR) approximately 10(exp 14) solar luminosity. The CO(3-2) emission was detected at the NRAO 12-m telescope, and its molecular gas mass was estimated to be (1-3)x10(exp 11) solar mass. This object is unique and important because it is the first high-z object from which molecular line emission is detected and it enables us to investigate molecular gas content, star forming material, at an early stage of galactic evolution. If IRAS F10214+4724 is a primeval galaxy at the formation process, it is possible the gas has not been collapsed yet to the galactic scale. On the other hand, it is also possible IRAS F10214+4724 is a merging or interacting system like the most of ultra-luminous infrared galaxies. However, since the first detection was made with a medium size single-dish telescope, the precise position, extent, and distribution of the molecular gas had not been determined. The aim of our aperture synthesis observations is therefore to determine position and distribution of molecular gas.

  3. 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}.

  4. Radiation hydrodynamic simulations of a super-Eddington accretor as a model for ultra-luminous sources

    NASA Astrophysics Data System (ADS)

    Ogawa, Takumi; Mineshige, Shin; Kawashima, Tomohisa; Ohsuga, Ken; Hashizume, Katsuya

    2017-04-01

    We perform two-dimensional radiation hydrodynamic (RHD) simulations of super-Eddington accretion flow and the accompanying outflow to investigate how they will be observed from various viewing directions. We consider gas flow around a 10 M⊙ black hole for mass injection rates of \\dot{M}_inj/{\\dot{M}_Edd}=102, 103, and 104 (in units of \\dot{M}_Edd≡ L_Edd/c^2, with LEdd and c being the Eddington luminosity and the speed of light, respectively), and solve gas dynamics and radiation transfer around the black hole, taking into account inverse Compton scattering. We confirm the tendency that the higher the mass accretion rate is, the larger the relative importance of outflow over accretion flow becomes. The observational appearance of the super-Eddington flow is distinct, depending on whether it is viewed from the edge-on direction or from the face-on direction. This is because nearly edge-on observers can only see the outer, cooler (∼106 K) surface of the inner, vertically inflated part of the flow. Observational properties are briefly discussed in the context of the ultra-luminous X-ray sources (ULXs), the extreme ULXs (E-ULXs), and the ultra-luminous supersoft sources (ULSs). We find that the extremely high luminosities of E-ULXs (L ∼ 1041 erg s-1) can be explained when the flow on to the black hole with ≳20 M⊙ with a very high accretion rate, {\\dot{m}}_{ acc} (≡ {{\\dot{M}}_{ acc}/ {\\dot{M}}_{ Edd}}) ≳ {103}, is observed from the nearly face-on direction. The high luminosity (∼1039 erg s-1) and the very soft blackbody-like spectra with temperatures around 0.1 keV, which are observed in the ULSs, can be explained if the super-Eddington flow with {\\dot{m}}_acc ˜ 102-103 is viewed from large viewing angles, θ ≳ 30°.

  5. Radiation hydrodynamic simulations of a super-Eddington accretor as a model for ultra-luminous sources

    NASA Astrophysics Data System (ADS)

    Ogawa, Takumi; Mineshige, Shin; Kawashima, Tomohisa; Ohsuga, Ken; Hashizume, Katsuya

    2017-03-01

    We perform two-dimensional radiation hydrodynamic (RHD) simulations of super-Eddington accretion flow and the accompanying outflow to investigate how they will be observed from various viewing directions. We consider gas flow around a 10 M⊙ black hole for mass injection rates of \\dot{M}_inj/{\\dot{M}_Edd}=102, 103, and 104 (in units of \\dot{M}_Edd≡ L_Edd/c^2, with LEdd and c being the Eddington luminosity and the speed of light, respectively), and solve gas dynamics and radiation transfer around the black hole, taking into account inverse Compton scattering. We confirm the tendency that the higher the mass accretion rate is, the larger the relative importance of outflow over accretion flow becomes. The observational appearance of the super-Eddington flow is distinct, depending on whether it is viewed from the edge-on direction or from the face-on direction. This is because nearly edge-on observers can only see the outer, cooler (∼106 K) surface of the inner, vertically inflated part of the flow. Observational properties are briefly discussed in the context of the ultra-luminous X-ray sources (ULXs), the extreme ULXs (E-ULXs), and the ultra-luminous supersoft sources (ULSs). We find that the extremely high luminosities of E-ULXs (L ∼ 1041 erg s-1) can be explained when the flow on to the black hole with ≳20 M⊙ with a very high accretion rate, \\dot{m}}_{ acc} (≡ {{\\dot{M}}_{ acc}/ {\\dot{M}}_{ Edd}}) ≳ {103}, is observed from the nearly face-on direction. The high luminosity (∼1039 erg s-1) and the very soft blackbody-like spectra with temperatures around 0.1 keV, which are observed in the ULSs, can be explained if the super-Eddington flow with \\dot{m}}_acc ˜ 102-103 is viewed from large viewing angles, θ ≳ 30°.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. The gravitationally lensed galaxy IRAS FSC10214+4724

    NASA Astrophysics Data System (ADS)

    Deane, Roger Paul

    2013-12-01

    We present a multi-wavelength analysis of IRAS FSC10214+4724 from radio to X-ray wavelengths. This is a gravitationally lensed galaxy at a redshift z=2.3 (3 Gyr after the Big Bang) which hosts prodigious star formation as well as an obscured active nucleus. We derive a new lens model for the system employing a Bayesian Markov Chain Monte Carlo algorithm with extended-source, forward ray-tracing. An array of spatially resolved maps (radio, millimetre, near-infrared, optical) trace different physical components which enables a high resolution, multi-wavelength view of a high-redshift galaxy beyond the capabilities of current telescopes. The spatially-resolved molecular gas total intensity and velocity maps reveal a reasonably ordered system, however there is evidence for minor merger activity. We show evidence for an extended, low-excitation gas reservoir that either contains roughly half the total gas mass or has a different CO-to-H_2 conversion ratio. Very Long Baseline Interferometry (VLBI) is used to detect what we argue to be the obscured active nucleus with an effective angular resolution of <50 pc at z=2.3. The source plane inversion places the VLBI detection to within milli-arcseconds of the modeled cusp caustic, resulting in a very large magnification (mu > 70) which is over an order of magnitude larger than the derived co magnification. This implies an equivalent magnification difference between the starburst and AGN components, yielding significant distortion to the global continuum spectral energy distribution (SED). A primary result of this work is therefore the demonstration that emission regions of differing size and position within a galaxy can experience significantly different magnification factors (> 1 dex) and therefore distort our view of high-redshift, gravitationally lensed sources. This not only raises caution against unsophisticated uses of IRAS FSC10214+4724 as an archetype high-redshift Ultra-Luminous Infra-Red Galaxy (ULIRG), but also

  11. 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.

  12. 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.

  13. IRIS: A New Generation of IRAS Maps

    NASA Astrophysics Data System (ADS)

    Miville-Deschênes, M.-A.; Lagache, G.

    2006-12-01

    In this contribution we present IRIS, a new generation of IRAS images at 12, 25, 60 and 100 μm. IRIS benefits from a better destriping, it keeps the full ISSA resolution, it includes well calibrated point sources and the diffuse emission calibration at scales smaller than 1° was corrected for the variation of the IRAS detector responsivity with scale and brightness. At 100 μm the IRIS product is also a significant improvement from the Schlegel et al. (1998) maps. The uncertainty on the IRIS calibration and zero level are dominated by the uncertainties on the DIRBE calibration and on the zodiacal light model.

  14. The classification of stars from IRAS colors

    NASA Technical Reports Server (NTRS)

    Walker, H. J.; Cohen, M.

    1988-01-01

    IRAS stars with reliable fluxes at 12, 25, and 60 microns were investigated which fell into three main types: (1) bright; (2) O-rich; and (3) C-rich. The three star types had a tendency to separate in the IRAS color-color diagram such that almost nonoverlapping zones could be defined for the groups with about 70 percent of the stars included. The O-rich stars tended to be redder in (12) - (25) than bright stars, and C-rich stars tended to be redder in (25) - (60) than bright and O-rich stars. It is suggested that the flattening of the underlying continuum slope may be the dominant cause of the change in (12) - (25). Of the 4300 unassociated IRAS point sources considered, amost 50 percent are late-type stars.

  15. 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.

  16. THE SPATIOKINEMATICAL STRUCTURE OF H{sub 2}O AND OH MASERS IN THE ''WATER FOUNTAIN'' SOURCE IRAS 18460-0151

    SciTech Connect

    Imai, Hiroshi; Deguchi, Shuji; Nakashima, Jun-ichi; Kwok, Sun; Diamond, Philip J. E-mail: deguchishuji60@gmail.com E-mail: sunkwok@hku.hk

    2013-08-20

    Using the Very Long Baseline Array and the European Very Long Baseline Interferometry Network, we have observed 22.2 GHz H{sub 2}O and 1612 MHz OH masers in the water fountain source IRAS 18460-0151. The H{sub 2}O maser spectrum has a very wide line-of-sight velocity range ( Almost-Equal-To 310 km s{sup -1}) and consists of three groups of emission features at the blueshifted (-68 km s{sup -1}{approx}< V{sub LSR} {approx}< -17 km s{sup -1}) and redshifted (V{sub LSR} {approx_equal} 240 km s{sup -1}) edges as well as around the systemic velocity (112 km s{sup -1} {approx}< V{sub LSR} {approx}< 133 km s{sup -1}). The first two H{sub 2}O spectral components exhibit a highly collimated high-velocity bipolar jet on the sky, with an angular separation of Almost-Equal-To 120 milliarcsec (mas) (240 AU in linear length) and a three-dimensional flow velocity of Almost-Equal-To 160 km s{sup -1}. The flow dynamical age is estimated to be only Almost-Equal-To 6 yr (at the time of the observation epochs of 2006-2007). Interestingly, the systemic velocity component clearly exhibits a spherically expanding outflow with a radius of Almost-Equal-To 36 AU and a flow velocity of Almost-Equal-To 9 km s{sup -1}. On the other hand, the OH maser spectrum shows double peaks with a velocity separation of Almost-Equal-To 25 km s{sup -1} (V{sub LSR} = 111-116 and 138-141 km s{sup -1}), as typically seen in circumstellar envelopes of OH/IR stars. The angular offset between the velocity-integrated brightness peaks of the two high-velocity H{sub 2}O components is Almost-Equal-To 25 mas (50 AU). The offset direction and the alignment of the redshifted maser spots are roughly perpendicular to the axis of the H{sub 2}O maser flow. High-accuracy astrometry for the H{sub 2}O and OH masers demonstrates that the collimated fast jet and the slowly expanding outflow originate from a single or multiple sources which are located within 15 mas (30 AU). On the other hand, the estimated systemic velocity of

  17. Suzaku observations of spectral variations of the ultra-luminous X-ray source Holmberg IX X-1

    NASA Astrophysics Data System (ADS)

    Kobayashi, Shogo B.; Nakazawa, Kazuhiro; Makishima, Kazuo

    2017-02-01

    Observations of the ultra-luminous X-ray source (ULX) Holmberg IX X-1 were carried out with Suzaku twice, once on 2012 April 13 and then on 2012 October 24, with exposures of 180 ks and 217 ks, respectively. The source showed a hard power-law shaped spectrum with a mild cutoff at ˜8 keV, which is typical of ULXs when they are relatively dim. On both occasions, the 0.6-11 keV spectrum was explained successfully in terms of a cool (˜0.2 keV) multi-color disk blackbody emission model and thermal Comptonization emission produced by an electron cloud with a relatively low temperature and high optical depth, assuming that a large fraction of the disk-blackbody photons are Comptonized whereas the rest are observed directly. The 0.5-10 keV luminosity was 1.2 × 1040 erg s-1 in April, and ˜14% higher in October. This brightening was accompanied by spectral softening in ≥2 keV, with little change in the ≤2 keV spectral shape. This behavior can be understood if the accretion disk remains unchanged while the electron cloud covers a variable fraction of the disk. The absorbing column density was consistent with the galactic line-of sight value, and did not vary by more than 1.6 × 1021 cm-2. Together with the featureless spectra, these properties may not be reconciled easily with the super-critical accretion scenario of this source.

  18. 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.

  19. High energy gamma rays from nebulae associated with extragalactic microquasars and ultra-luminous X-ray sources

    NASA Astrophysics Data System (ADS)

    Inoue, Yoshiyuki; Lee, Shiu-Hang; Tanaka, Yasuyuki T.; Kobayashi, Shogo B.

    2017-04-01

    In the extragalactic sky, microquasars and ultra-luminous X-ray sources (ULXs) are known as energetic compact objects locating at off-nucleus positions in galaxies. Some of these objects are associated with expanding bubbles with a velocity of 80-250 km s - 1. We investigate the shock acceleration of particles in those expanding nebulae. The nebulae having fast expansion velocity ≳ 120km s - 1 are able to accelerate cosmic rays up to ∼100 TeV. If 10% of the shock kinetic energy goes into particle acceleration, powerful nebulae such as the microquasar S26 in NGC 7793 would emit gamma rays up to several tens TeV with a photon index of ∼2. These nebulae will be good targets for future Cherenkov Telescope Array observations given its sensitivity and angular resolution. They would also contribute to ∼7% of the unresolved cosmic gamma-ray background radiation at ≥ 0.1 GeV. In contrast, particle acceleration in slowly expanding nebulae ≲ 120km s - 1 would be less efficient due to ion-neutral collisions and result in softer spectra at ≳ 10 GeV.

  20. 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.

  1. The IRAS galaxy 0421+040P06: An active spiral (?) galaxy with extended radio lobes

    NASA Technical Reports Server (NTRS)

    Beichman, C. A.; Wynn-Williams, C. G.; Lonsdale, C. J.; Persson, S. E.; Heasley, J. N.; Miley, G. K.; Soifer, B. T.; Neugebauer, G.; Becklin, E. E.; Houck, J. R.

    1984-01-01

    The infrared bright galaxy 0421+040P06 detected by IRAS at 25 and 60 microns was studied at optical, infrared, and radio wavelength. It is a luminous galaxy with apparent spiral structure emitting 4 x 10 to the 37th power from far-infrared to optical wavelengths. Optical spectroscopy reveals a Seyfert 2 emission line spectrum, making 0421+040P06 the first active galaxy selected from an unbiased infrared survey of galaxies. The fact that this galaxy shows a flatter energy distribution with more 25 micron emission than other galaxies in the infrared sample may be related to the presence of an intense active nucleus. The radio observations reveal the presence of a non-thermal source that, at 6 cm, shows a prominent double lobed structure 20 to 30 kpc in size extending beyond the optical confines of the galaxy. The radio source is three to ten times larger than structures previously seen in spiral galaxies.

  2. 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.

  3. 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.

  4. 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…

  5. 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…

  6. 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.

  7. Luminous supernovae.

    PubMed

    Gal-Yam, Avishay

    2012-08-24

    Supernovae, the luminous explosions of stars, have been observed since antiquity. However, various examples of superluminous supernovae (SLSNe; luminosities >7 × 10(43) ergs per second) have only recently been documented. From the accumulated evidence, SLSNe can be classified as radioactively powered (SLSN-R), hydrogen-rich (SLSN-II), and hydrogen-poor (SLSN-I, the most luminous class). The SLSN-II and SLSN-I classes are more common, whereas the SLSN-R class is better understood. The physical origins of the extreme luminosity emitted by SLSNe are a focus of current research.

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    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 microns using the Herschel and Spitzer space observatories. The Herschel PACS maps exhibit a compact, slightly asymmetric continuum source at 170 microns, indicative of a large, dusty circumstellar envelope. The far-IR CO emission line spectrum reveals two gas temperature components: approx. = 0.22 Stellar Mass of material at 280+/-18 K, and ˜1.6 Me of material at 157+/-3 K. The OI 63 micron 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 along the line of sight. From Spitzer spectroscopy, we identify ice absorption bands due to H2O at 5.8 microns and CO2 at 15 microns. The spectral energy distribution is consistent with a massive, luminous (approx. 2 × 10(exp 4) Stellar Luminosity) central source surrounded by a dense, warm circumstellar disk and envelope of total mass approx. 500-700 Stellar Mass with large bipolar outflow cavities. The combination of distinctive far-IR spectral features suggest that IRAS19312+1950 should be classified as an accreting, high-mass YSO rather than an evolved star. In light of this reclassification, IRAS19312+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.

  9. Millimetre observations of the IRAS 18162-2048 outflow: evidence for cloud disruption around an intermediate-mass protostar

    NASA Astrophysics Data System (ADS)

    Benedettini, M.; Molinari, S.; Testi, L.; Noriega-Crespo, A.

    2004-01-01

    In order to study the morphology and the dynamics of the molecular outflow associated with IRAS 18162-2048, a wide area of ~95 arcmin2 around the source has been mapped by means of CO and 13CO (1-0) lines, and has been complemented by a map of a smaller region surrounding the high-mass object using the C18O (1-0) and CH3OH (2k-1k) and (3k-2k) transitions. The lines profile reveals the presence of several velocity components among which two major line components at 11.9 and 12.8 km s-1 have been detected in all the tracers. Simple morphological and energetic considerations led us to interpret the observations in a relatively straightforward scenario in which the powerful jet ejected by IRAS 18162-2048 sets a big portion of the surrounding molecular cloud into motion. The energy and momentum deposited by the flow break the cloud apart, shifting the northern region to a blue velocity and the southern region to a red velocity, and giving rise to a giant outflow. We calculated the physical parameters of the outflow, which make the IRAS 18162-2048 outflow one of the most massive (M= 570 Msolar) and energetic (K > 1046 erg) known. Despite the intrinsic difficulties in giving a precise value of the age and of the inclination angle of the flow, we used different methods to derive a reliable estimate. Our data show evidence in favour of a small inclination angle (<50°) and of a maximum outflow age of ~106 yr. C18O and CH3OH trace the dense core surrounding IRAS 18162-2048 and show an elongated emission in the direction perpendicular to the outflow axis. Besides the peak emission associated with the IRAS source, we found another peak at the position which coincides with a red near-infrared source. We provided evidence that this second peak may be surrounded by a flattened rotating structure, suggesting that the newly discovered infrared source can be another site of recent star formation in this region. Our analysis suggest that the powerful wind/outflow from the luminous

  10. 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

  11. 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.

  12. Optimizing spectral compositions of multichannel LED light sources by IES color fidelity index and luminous efficacy of radiation.

    PubMed

    Zhang, Fuzheng; Xu, Haisong; Wang, Zhehong

    2017-03-01

    The trade-off between the color fidelity index (Rf) released recently by the Illuminating Engineering Society of North America (IES) and luminous efficacy of radiation (LER) was investigated by adjusting the peak wavelengths, spectral widths, and intensities of four-channel LEDs utilizing a multiobjective optimization algorithm based on differential evolution in the correlated color temperature (CCT) ranging from 2800 to 6500 K for general lighting. The results indicate that Rf at a specific LER value decreases with the increasing CCT, and vice versa, and that Rf has significant improvements over the Commission Internationale de l'Eclairage (CIE) color rendering index (CRI) in avoiding spectral gaming and evaluating the light sources even with negative CIE general CRI (Ra). Further, the optimal peak wavelengths with regard to Rf were identified as 629 nm, 568 nm, 504 nm, and 447 nm, yielding high color rendering in terms of Rf(93∼94) and Ra(95∼97) and relatively excellent LER (299  lm/W∼339  lm/W) over a wide range of CCTs from 2800 to 6500 K. This suggests that Rf can be compatible with Ra, making it possible to obtain a common set of optimal peak wavelengths for Rf and Ra. Besides, the IES method could assess saturated red and skin tones more fairly than the CIE CRI. With a practical 17-channel LED array covering the resulted four optimal peak wavelengths, the improvements of the IES method over the CIE CRI were validated further.

  13. Binary black hole merger rates inferred from luminosity function of ultra-luminous X-ray sources

    NASA Astrophysics Data System (ADS)

    Inoue, Yoshiyuki; Tanaka, Yasuyuki T.; Isobe, Naoki

    2016-10-01

    The Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) has detected direct signals of gravitational waves (GWs) from GW150914. The event was a merger of binary black holes whose masses are 36^{+5}_{-4} M_{{⊙}} and 29^{+4}_{-4} M_{{⊙}}. Such binary systems are expected to be directly evolved from stellar binary systems or formed by dynamical interactions of black holes in dense stellar environments. Here we derive the binary black hole merger rate based on the nearby ultra-luminous X-ray source (ULX) luminosity function (LF) under the assumption that binary black holes evolve through X-ray emitting phases. We obtain the binary black hole merger rate as 5.8(tULX/0.1 Myr)- 1λ- 0.6exp ( - 0.30λ) Gpc- 3 yr- 1, where tULX is the typical duration of the ULX phase and λ is the Eddington ratio in luminosity. This is coincident with the event rate inferred from the detection of GW150914 as well as the predictions based on binary population synthesis models. Although we are currently unable to constrain the Eddington ratio of ULXs in luminosity due to the uncertainties of our models and measured binary black hole merger event rates, further X-ray and GW data will allow us to narrow down the range of the Eddington ratios of ULXs. We also find the cumulative merger rate for the mass range of 5 M⊙ ≤ MBH ≤ 100 M⊙ inferred from the ULX LF is consistent with that estimated by the aLIGO collaboration considering various astrophysical conditions such as the mass function of black holes.

  14. 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.

  15. 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.

  16. 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.

  17. Monsters and babies from the first/IRAS survey

    SciTech Connect

    Van Bruegel, W J M

    1999-02-16

    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-sleected, 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 et al. 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 possibile 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). While we used radio-selected FIR sources to search for evidence of a causal AGN/starburst connection, we conclude our

  18. 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.

  19. The IRAS Minor Planet Survey

    DTIC Science & Technology

    1992-12-01

    tronomical Satellite (IRAS) and to compute albedos and diameters from their IRAS fluxes. It also presents listings of the results obtained. These...how this material should be referenced. The primary purpose of the Infrared Astronomical Satellite (IRAS) was to survey the sky in four wavelength...bands centered near 12, 25, 60 and 100 pm. The satellite was launched in January 1983 and obtained observations until November 1983. In this period it

  20. Proper motion of H_2O masers in IRAS 20050+2720 MMS1: an AU scale jet associated with an intermediate-mass class 0 source

    NASA Astrophysics Data System (ADS)

    Furuya, R. S.; Kitamura, Y.; Wootten, A.; Claussen, M. J.; Kawabe, R.

    2005-08-01

    We conducted a 4 epoch, 3 month, VLBA proper motion study of H2O masers toward an intermediate-mass class 0 source ı20 MMS1 (d=700 pc). The region of ı20 contains at least 3 bright young stellar objects at millimeter to submillimeter wavelengths and shows three pairs of CO outflow lobes: the brightest source MMS1, which shows an extremely high velocity (EHV) wing emission, is believed to drive the outflow(s). From milli-arcsecond (mas) resolution VLBA images, we found two groups of H2O maser spots at the center of the submillimeter core of MMS1. One group consists of more than ˜ 50 intense maser spots; the other group consisting of several weaker maser spots is located at 18 AU south-west of the intense group. Distribution of the maser spots in the intense group shows an arc-shaped structure which includes the maser spots that showed a clear velocity gradient. The spatial and velocity structures of the maser spots in the arc-shape did not significantly change through the 4 epochs. Furthermore, we found a relative proper motion between the two groups. Their projected separation increased by 1.13±0.11 mas over the 4 epochs along a line connecting them (corresponding to a transverse velocity of 14.4 km s-1). The spatial and velocity structures of the intense group and the relative proper motions strongly suggest that the maser emission is associated with a protostellar jet. Comparing the observed LSR velocities with calculated radial velocities from a simple biconical jet model, we conclude that the most of the maser emission is likely to be associated with an accelerating biconical jet that has large opening angle of about 70°. The large opening angle of the jet traced by the masers would support the hypothesis that poor jet collimation is an inherent property of luminous (proto)stars.

  1. Accretion Disk Spectra of the Ultra-Luminous X-Ray Sources in Nearby Spiral Galaxies and Galactic Superluminal Jet Sources

    SciTech Connect

    Mizuno, T

    2003-12-11

    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 (> 300 M{sub solar}). 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 that their X-ray emission is from the slim disk shining at super-Eddington luminosities.

  2. 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.

  3. 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).

  4. [The role of IRA B cells in selected inflammatory processes].

    PubMed

    Zasada, Magdalena; Rutkowska-Zapała, Magdalena; Lenart, Marzena; Kwinta, Przemko

    2016-03-16

    The first report about the discovery of new, previously unknown immune cells named IRA B cells (innate response activator B cells) appeared in 2012. So far, their presence has been verified in both mice and humans. However, IRA B cells belong to the family of B lymphocytes and have a number of characteristics unique to this group of cells. IRA B cells are formed from activated B1a lymphocytes after their contact with a pathogen. B1a lymphocytes mainly reside within body cavities. Activated by the pathogen, they move on into secondary lymphoid organs (spleen, lymph nodes) where they differentiate into IRA B cells. IRA B cells are a rich source of granulocyte-macrophage colony stimulating factor (GM-CSF). GM-CSF can stimulate IRA B cells in an autocrine manner for the secretion of intracellular stocks of immunoglobulin M (IgM), which can facilitate pathogens' phagocytosis by neutrophils. GM-CSF also stimulates neutrophils into active phagocytosis. Rapid eradication of the pathogen can prevent the development of an excessive inflammatory response, which can be dangerous for the organism. Until now the involvement of IRA B lymphocytes in the pathogenesis of sepsis and pneumonia has been proven, as well as their role in the progression of atherosclerotic lesions in mice. There is research in progress on the possibility of increasing the number of IRA B cells, for example by intravenous supply of modified immunoglobulins. It is necessary to characterize human IRA B cells and to determine their role in the functioning of the immune system.

  5. IRIS: A New Generation of IRAS Maps

    NASA Astrophysics Data System (ADS)

    Miville-Deschênes, Marc-Antoine; Lagache, Guilaine

    2005-04-01

    The Infrared Astronomical Satellite (IRAS) had a tremendous impact on many areas of modern astrophysics. In particular, it revealed the ubiquity of infrared cirrus that are a spectacular manifestation of the interstellar medium complexity but also an important foreground for observational cosmology. With the forthcoming Planck satellite there is a need for all-sky complementary data sets with arcminute resolution that can bring informations on specific foreground emissions that contaminate the cosmic microwave background radiation. With its ~4' resolution matching perfectly the high-frequency bands of Planck, IRAS is a natural data set to study the variations of dust properties at all scales. But the latest version of the images delivered by the IRAS team (the ISSA plates) suffer from calibration, zero level, and striping problems that can preclude its use, especially at 12 and 25 μm. In this paper we present how we proceeded to solve each of these problems and enhance significantly the general quality of the ISSA plates in the four bands (12, 25, 60, and 100 μm). This new generation of IRAS images, called IRIS, benefits from a better zodiacal light subtraction, from a calibration and zero level compatible with DIRBE, and from a better destriping. At 100 μm the IRIS product is also a significant improvement from the Schlegel et al. maps. IRIS keeps the full ISSA resolution, it includes well-calibrated point sources, and the diffuse emission calibration at scales smaller than 1° was corrected for the variation of the IRAS detector responsivity with scale and brightness. The uncertainty on the IRIS calibration and zero level is dominated by the uncertainty on the DIRBE calibration and on the accuracy of the zodiacal light model.

  6. A Compton-thick active galactic nucleus powering the hyperluminous infrared galaxy IRAS 00182-7112

    NASA Astrophysics Data System (ADS)

    Nandra, K.; Iwasawa, K.

    2007-11-01

    We present X-ray observations of the hyperluminous infrared galaxy (HLIRG) IRAS 00182- 7112 obtained using the XMM-Newton EPIC camera. A luminous hard X-ray source coincident with the nucleus is revealed, along with weaker soft X-ray emission which may be extended or offset from the hard emission. The EPIC spectrum is extremely flat and shows Fe Kα emission with very high equivalent width: both are typical characteristics of a buried, Compton-thick active galactic nucleus (AGN) which is seen only in scattered light. Perhaps the most remarkable characteristic of the spectrum is that the Fe Kα line energy is that of He-like iron, making IRAS 00182-7112 the first hidden AGN known to be dominated by ionized, Compton-thick reflection. Taking an appropriate bolometric correction, we find that this AGN could easily dominate the far-infrared (FIR) energetics. The nuclear reflection spectrum is seen through a relatively cold absorber with column density consistent with recent Spitzer observations. The soft X-ray emission, which may be thermal in nature and associated with star-forming activity, is seen unabsorbed. The soft X-rays and weak polycyclic aromatic hydrocarbon features both give estimates of the star formation rate ~300Msolar yr-1, insufficient to power the FIR emission and supportive of the idea that this HLIRG is AGN-dominated.

  7. 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.

  8. 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.

  9. 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.

  10. [IRA protection. Needs and possibilities].

    PubMed

    Schroeder, P; Krutmann, J

    2009-04-01

    When it comes to skin damage, solar radiation is often regarded to be identical to ultraviolet (UV) but it includes much more. Over 90% of solar radiation is in the non-UV-range. Infrared A radiation (IRA, 760-1440 nm) accounts for around 30% of the solar energy reaching the earth's surface and exert detrimental effects on the skin. IRA alters the collagen equilibrium of the dermal extracellular matrix by leading to an increased expression of the collagen degrading enzyme matrixmetalloproteinase-1 while decreasing the expression of the dominant collagen gene Col1alpha1. IRA therefore leads to endpoints similar to UV, but the underlying biological mechanisms are substantially different. IRA acts via the mitochondria. IRA-specific protective approaches should be added to conventional sun protections strategies.

  11. Observations of water maser sources at Arcetri

    NASA Astrophysics Data System (ADS)

    Comoretto, Giovanni; Valdettaro, Riccardo; Palla, Francesco; Brand, Jan; Cesaroni, Riccardo; Felli, Marcello; Natale, Enzo; Palagi, Francesco; Panella, Dario; Tofani, Gianni

    We present the current activity of the Arcetri group in the field of water masers. This is mainly represented by observations with the Medicina radiotelescope, whose main outcome has been the compilation of the Arcetri Catalog and the study of time variability of selected sources. The Arcetri Catalog update reports the results of the observations carried out from January 1993 to April 2000 on a sample of 300 sources. The global properties of the complete Arcetri Catalog (including Comoretto et al. 1990, and Brand et al. 1994) are discussed. Of the 1013 sources, 937 have an IRAS counterpart within 1 arcmin from the nominal position of the maser. We establish a classification scheme based on the IRAS flux densities which allows to distinguish between water masers associated with star forming regions and late-type stars. The time variability study shows a large variety of behaviors. Generally more luminous sources present less variable emission and spectral components over a wider velocity range.

  12. 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

  13. The broad band X-ray spectrum of SN 1978k and two other luminous X-ray sources in the spiral galaxy NGC 1313

    NASA Technical Reports Server (NTRS)

    Petre, Robert; Okada, Kyoko; Mihara, Tatehiro; Makishima, Kazuo; Colbert, Edward J. M.

    1994-01-01

    We present preliminary results of our analysis of the Advanced Satellite for Cosmology and Astrophysics (ASCA) PV phase observation of the nearby spiral galaxy NGC 1313. ASCA cleanly resolves the three previously known luminous sources, one of which is the very luminous supernova, SN 1978k. The spectrum of SN 1978k is described by either a power law with a photon index gamma approximately 2.2 or a thermal model with temperature kT approximately 3.0 keV and abundances Z approximately 0.2 Z(sun). There is no evidence for strong line emission from it or from the other two sources. The spectrum of SN 1978k arises either in shocked gas in extreme departure from ionization equilibrium or from synchrotron processes associated with a newborn pulsar. A second source, near the galactic center, is well-fit by a power-law with a photon index of approximately 1.8. It is possibly an active nucleus-like source, but physically displaced from the optical nucleus of the galaxy. The spectrum of the third source, located 8 kpc south of the nucleus, along with the absence of an optical counterpart, suggests that it is a low mass X-ray binary; but its high X-ray luminosity clouds this interpretation. This observation demonstrates the ability of ASCA to perform effective broad band spectroscopic measurements of sources at a 2-10 keV flux level of 5 x 10(exp -13) erg cm(exp -2) s(exp -1).

  14. Blue light hazard optimization for white light-emitting diode sources with high luminous efficacy of radiation and high color rendering index

    NASA Astrophysics Data System (ADS)

    Zhang, Jingjing; Guo, Weihong; Xie, Bin; Yu, Xingjian; Luo, Xiaobing; Zhang, Tao; Yu, Zhihua; Wang, Hong; Jin, Xing

    2017-09-01

    Blue light hazard of white light-emitting diodes (LED) is a hidden risk for human's photobiological safety. Recent spectral optimization methods focus on maximizing luminous efficacy and improving color performances of LEDs, but few of them take blue hazard into account. Therefore, for healthy lighting, it's urgent to propose a spectral optimization method for white LED source to exhibit low blue light hazard, high luminous efficacy of radiation (LER) and high color performances. In this study, a genetic algorithm with penalty functions was proposed for realizing white spectra with low blue hazard, maximal LER and high color rendering index (CRI) values. By simulations, white spectra from LEDs with low blue hazard, high LER (≥297 lm/W) and high CRI (≥90) were achieved at different correlated color temperatures (CCTs) from 2013 K to 7845 K. Thus, the spectral optimization method can be used for guiding the fabrication of LED sources in line with photobiological safety. It is also found that the maximum permissible exposure duration of the optimized spectra increases by 14.9% than that of bichromatic phosphor-converted LEDs with equal CCT.

  15. Analysis of IRAS solar system dust data

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.; Nicholson, P. D.

    1991-01-01

    Data in the Infrared Astronomical Satellite (IRAS) Zodiacal History File were analyzed to extract dust band locations and peak brightness measurements from approximately 1,000 individual IRAS scans. The study had three goals. One was to show that the prominent solar system dust bands are associated with Hirayama asteroid families and thus that collisions between asteroids account for a significant fraction of the particles in the zodiacal cloud. Recent work suggests that while the Hirayama families are a major source of the dust in the bands, there may also be contributions from two or three smaller, more recently recognized asteroid families. A second goal was to show that there is evidence in the IRAS dust data for the transport of particles from asteroid belt to the Earth by Poynting-Robertson light drag and thus account for the fact that asteroid particles are collected in the Earth's stratosphere. Results of the study will confirm the location of the dust bands within the inner asteroid belt, and show conclusively that the material seen by IRAS is now spread over a wide range of distances from the sun. The third goal was to construct a model of the background zodiacal cloud that satisfies the proper dynamical constraints. Figures are provided to show the scans processed to remove zodiacal background and Galactic signals, and the resulting polynomial fits to the 25 micron scan. The latter provided objective estimates of band widths, peak locations, and peak fluxes. Modelling and analysis of the resulting band data has been presented at several conferences and is the subject of a number of forthcoming papers.

  16. IRAS colors of the Pleiades.

    NASA Astrophysics Data System (ADS)

    Carey, S. J.; Shipman, R. F.; Clark, F. O.

    1996-10-01

    The authors present large scale images of the infrared emission of the region around the Pleiades using the ISSA data product from the IRAS mission. A new method of identifying dense molecular material through infrared emission properties is presented.

  17. 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

  18. IRAS Colors of the Pleiades

    NASA Technical Reports Server (NTRS)

    Carey, Sean J.; Shipman, R. F.; Clark, F. O.

    1996-01-01

    We present large scale images of the infrared emission of the region around the Pleiades using the ISSA data product from the IRAS mission. Residual Zodiacal background and a discontinuity in the image due to the scanning strategy of the satellite necessitated special background subtraction methods. The 60/100 color image clearly shows the heating of the ambient interstellar medium by the cluster. The 12/100 and 25/100 images peak on the cluster as expected for exposure of small dust grains to an enhanced UV radiation field; however, the 25/100 color declines to below the average interstellar value at the periphery of the cluster. Potential causes of the color deficit are discussed. A new method of identifying dense molecular material through infrared emission properties is presented. The difference between the 100 micron flux density and the 60 micron flux density scaled by the average interstellar 60/100 color ratio (Delta I(sub 100) is a sensitive diagnostic of material with embedded heating sources (Delta I(sub 100) less than 0) and cold, dense cores (Delta I(sub 100) greater than 0). The dense cores of the Taurus cloud complex as well as Lynds 1457 are clearly identified by this method, while the IR bright but diffuse Pleiades molecular cloud is virtually indistinguishable from the nearby infrared cirrus.

  19. Clustering of very luminous infrared galaxies and their environment

    NASA Technical Reports Server (NTRS)

    Gao, YU

    1993-01-01

    The IRAS survey reveals a class of ultraluminous infrared (IR) galaxies (ULIRG's) with IR luminosities comparable to the bolometric luminosities of quasars. The nature, origin, and evolution of ULIRG's are attracting more and more attention recently. Since galaxy morphology is certainly a function of environment, morphological observations show that ULIRG's are interacting/merging galaxies, and some ULIRG's might be the dust-enshrouded quasars (S88) or giant ellipticals, the study of ULIRG's environment and large scale clustering effects should be worthwhile. ULIRG's and very luminous IR galaxies have been selected from the 2Jy IRAS redshift survey. Meanwhile, a catalog of IRAS groups of galaxies has been constructed using a percolation-like algorithm. Therefore, whether ULIRG's and/or VLIRG's have a group environment can be checked immediately. Other aspects of the survey are discussed.

  20. Evolutionary status of dense cores in the NGC 1333 IRAS 4 star-forming region

    NASA Astrophysics Data System (ADS)

    Koumpia, E.; van der Tak, F. F. S.; Kwon, W.; Tobin, J. J.; Fuller, G. A.; Plume, R.

    2016-10-01

    Context. Protostellar evolution after the formation of the protostar is becoming reasonably well characterized, but the evolution from a prestellar core to a protostar is not well known, although the first hydrostatic core (FHSC) must be a pivotal step. Aims: NGC 1333 - IRAS 4C is a potentially very young object that we can directly compare with the nearby Class 0 objects IRAS 4A and IRAS 4B. Observational constraints are provided by spectral imaging from the JCMT Spectral Legacy Survey (330-373 GHz). We present integrated intensity and velocity maps of several species, including CO, H2CO and CH3OH. CARMA observations provide additional information with which we can distinguish IRAS 4C from other evolutionary stages. Methods: We present the observational signatures of the velocity of an observed outflow, the degree of CO depletion, the deuterium fractionation of [DCO+]/[HCO+], and gas kinetic temperatures. Results: We report differences between the three sources in four aspects: a) the kinetic temperature as probed using the H2CO lines is much lower toward IRAS 4C than the other two sources; b) the line profiles of the detected species show strong outflow activity toward IRAS 4A and IRAS 4B, but not toward IRAS 4C; c) the HCN/HNC is <1 toward IRAS 4C, which confirms the cold nature of the source; d) the degree of CO depletion and the deuteration are lowest toward the warmest of the sources, IRAS 4B. Conclusions: IRAS 4C seems to be in a different evolutionary state than the sources IRAS 4A and IRAS 4B. We can probably exclude the FHSC stage becaues of the relatively low Lsmm/Lbol ( 6%), and we investigate the earliest accretion phase of Class 0 stage and the transition between Class 0 to Class I. Our results do not show a consistent scenario for either case; the main problem is the absence of outflow activity and the cold nature of IRAS 4C. The number of FHSC candidates in Perseus is 10 times higher than current models predict, which suggests that the lifespan of

  1. IRAS study of interacting galaxies

    NASA Astrophysics Data System (ADS)

    Allam, S.

    1998-04-01

    Interacting galaxies are ideal laboratories for studying the influence of gravitational forces on galaxies. From theoretical and observational studies, we know how sensitive galaxies are to tidal interaction, from the formation of tidal tails, bridges, bursts of star formation up to a complete merging of the galaxies. The Far Infrared (FIR) properties of interacting galaxies give information on the dynamical and physical properties of these systems. Several earlier studies using the IRAS point source catalogue (IPSC) and IRAS Faint Source Survey (FSS), showed that the FIR emission from interacting/merging galaxies is enhanced with respect to isolated non-interacting galaxies; moreover, that high density environments have more influence in producing enhanced FIR emission over isolated interacting systems. In general the ratio of FIR to optical luminosity in interacting systems was found to be enhanced. It is regarded as an increased star formation (SF) rate in these systems. Later on, due to the rather high IPSC detection threshold, and its low resolution, several contradictory results have been reported. In this thesis the FIR emission from interacting galaxies is studied by using the high resolution IRAS software introduced by Bontekoe et al. (1994). This soft ware package uses a Maximum Entropy method (hereafter MaxEnt). The MaxEnt formulation is rooted in Bayesian probability theory. The raw IRAS data contains the Point Spread Function (PSF) of both the telescope mirror (60 cm --> 1 arcmin at 60 μm) and the PSF of the detectors (≃ 5 arcmin). Since there is much redundancy in the data, the MaxEnt routine can be used to remove the 5 arcmin PSF from the detectors. For many interacting galaxies this is enough to resolve them. The size of the images was chosen such that the objects could be studied including their surroundings. The absolute position calibration and flux estimates for the MaxEnt images are described in Allam et al. (1996). Because of the high

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  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. Ionized Gas Kinematics around an Ultra-luminous X-Ray Source in NGC 5252: Additional Evidence for an Off-nuclear AGN

    NASA Astrophysics Data System (ADS)

    Kim, Minjin; Ho, Luis C.; Im, Myungshin

    2017-08-01

    The Seyfert 2 galaxy NGC 5252 contains a recently identified ultra-luminous X-ray (ULX) source that has been suggested to be a possible candidate off-nuclear low-mass active galactic nucleus. We present follow-up optical integral-field unit observations obtained using Gemini Multi-Object Spectrographs on the Gemini-North telescope. In addition to confirming that the ionized gas in the vicinity of the ULX is kinematically associated with NGC 5252, the new observations reveal ordered motions consistent with rotation around the ULX. The close coincidence of the excitation source of the line-emitting gas with the position of the ULX further suggests that ULX itself is directly responsible for the ionization of the gas. The spatially resolved measurements of [N ii] λ6584/Hα surrounding the ULX indicate a low gas-phase metallicity, consistent with those of other known low-mass active galaxies but not that of its more massive host galaxy. These findings strengthen the proposition that the ULX is not a background source but rather that it is the nucleus of a small, low-mass galaxy accreted by NGC 5252.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Parallel Computing and the IRAS Galaxy Atlas

    NASA Astrophysics Data System (ADS)

    Cao, Yu

    1997-09-01

    The Infrared Astronomical Satellite carried out a nearly complete survey of the infrared sky, and the survey data are important for the study of many astrophysical phenomena. However, many data sets at other wavelengths have higher resolutions than that of the co-added IRAS maps (4'-5'), and high resolution IRAS images are strongly desired both for their own information content and their usefulness in correlation studies. The HIRES program was developed by the Infrared Processing and Analysis Center (IPAC) to produce high resolution (~1') images from IRAS data using the maximum correlation method (MCM). We describe the port of HIRES to the Intel Paragon, a massively parallel supercomputer, and other software tools developed for mass production of HIRES images. striping and ringing artifacts. Correcting detector gain offsets in the reconstruction scheme was found to be effective in suppressing the striping artifacts. A variation of the destriping algorithm was used to subtract zodiacal emission. Using a Burg entropy metric in the image space gave good ringing suppression results for some test cases, but was found to have difficulties with photometry and resolution enhancement and hence not used in subsequent image production. A different ringing suppression algorithm was later developed, which aims to maximize cross log entropy between measured and modeled data. The algorithm suppresses point source ringing, and gave scientifically superior image for the α Ori test field. A partial convergence proof for the log entropy algorithm was achieved. HIRES images in the 60 and 100 μm wavelength bands were produced for the Galactic plane (-4.7oIRAS Galaxy Atlas

  14. 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.

  15. VLBA observations of the nuclear transient AT 2017gbl in IRAS 23436+5257

    NASA Astrophysics Data System (ADS)

    Perez-Torres, Miguel; Kool, Erik; Ryder, Stuart; Mattila, Seppo; Fraser, Morgan; Kankare, Erkki

    2017-09-01

    We report on simultaneous radio interferometric observations of the luminous nuclear transient AT 2017gbl, carried out at 4.4 and 7.6 GHz with the Very Long Baseline Array (VLBA) on 2017 August 15.38 UT. AT 2017gbl was discovered in the near-infrared on MJD 57942.56 (ATel #10651) superimposed on the nucleus of the galaxy IRAS 23436+5257 (D= 146 Mpc).

  16. 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.

  17. NuSTAR results on Ultra-Luminous X-ray sources: black holes or neutron stars?

    NASA Astrophysics Data System (ADS)

    Fuerst, Felix

    2015-04-01

    Ultraluminous X-ray sources (ULXs) are extremely bright, off-nuclear point sources in nearby galaxies. The only process known to power them is a very high accretion rate onto a compact object. If the compact object is similar to those observed in our own galaxy, i.e., a standard stellar remnant, the accretion rate has to exceed the Eddington rate by a factor of 10-100 in a so-called super-Eddington accretion regime. If on the other hand the compact were more massive, ULXs would be the only known evidence for intermediate mass black holes with masses of 100's or 1000's solar masses. Broadband spectral studies of a sample of ULXs, making full use of the hard X-ray sensitivity of the Nuclear Spectroscopic Telescope Array (NuSTAR), are suggestive of super-Eddington accretion. A definitive answer has, however, not yet been reached owing to continued difficulty constraining ULX masses. I will report on recent, multi-epoch NuSTAR observations, which allow us to examine the evolution of these enigmatic sources and their accretion process by studying their time variability and hard X-ray spectrum above 10keV. In a surprising discovery we have recently shown that the ULX M82 X-2 harbors a neutron star, the first evidence for a neutron star in a ULX. I will discuss possible modes of super-Eddington accretion on neutron stars and compare M82 X-2 to known accreting neutron stars in our galaxy. On behalf of the NuSTAR ULX science team led by Fiona Harrison.

  18. XMMU J010147.5-715550, another luminous supersoft X-ray source with a Be optical counterpart

    NASA Astrophysics Data System (ADS)

    Cracco, Valentina; Ciroi, Stefano; Orio, Marina; Colmenero, Encarni Romero; Gallagher, Jay; Kotulla, Ralf

    2016-11-01

    The Small Magellanic Cloud putative B star suggested to be the optical counterpart of the transient or recurrent XMM supersoft X-ray source XMMU J010147.5-715550 (Sturm et al., 2012, A & A 57, 76) was observed by us on September 7th, 2016 (JD 2457640.5) with the Southern African Large Telescope (SALT) at the South African Astronomical Observatory (SAAO) and the Robert Stobie Spectrograph (RSS), equipped with the PG0900 grating in longslit mode, with a slit width of 1 arcsecond.

  19. Star formation and AGN activity in the most luminous LINERs in the local universe

    NASA Astrophysics Data System (ADS)

    Márquez, I.; Povic, M.; Netzer, H.; Masegosa, J.; Nordon, R.; Pérez, E.; Schoenell, W.

    2017-03-01

    This work presents the properties of 42 objects in the group of the most luminous, highest star formation rate (SFR) low-ionization nuclear emission-line regions (LINERs) at z = 0.04 - 0.11. We obtained long-slit spectroscopy of the nuclear regions for all sources, and FIR data (Herschel and IRAS) for 13 of them.We measured emission-line intensities, extinction, stellar populations, stellar masses, ages, active galactic nuclei (AGN) luminosities, and SFRs. We find considerable differences from other low-redshift LINERs, and general similarity to star-forming galaxies. We confirm the existence of such luminous LINERs in the local universe, after being previously detected at z˜0.3 by Tommasin et al. The median stellar mass of these LINERs corresponds to 6 - 7× 10^{10} M_⊙ which was found in previous works to correspond to the peak of relative growth rate of stellar populations and therefore for the highest SFRs. Other LINERs although showing similar AGN luminosities have lower SFR. We find that most of these sources have LAGN ˜ LSF suggesting co-evolution of black hole and stellarmass. In general, the fraction of local LINERs on the main sequence of star-forming galaxies is related to their AGN luminosity.

  20. Star formation and AGN activity in the most luminous LINERs in the local universe

    NASA Astrophysics Data System (ADS)

    Pović, Mirjana; Márquez, Isabel; Netzer, Hagai; Masegosa, Josefa; Nordon, Raanan; Pérez, Enrique; Schoenell, William

    2016-11-01

    This work presents the properties of 42 objects in the group of the most luminous, highest star formation rate (SFR) low-ionization nuclear emission-line regions (LINERs) at z = 0.04-0.11. We obtained long-slit spectroscopy of the nuclear regions for all sources, and FIR data (Herschel and IRAS) for 13 of them. We measured emission-line intensities, extinction, stellar populations, stellar masses, ages, active galactic nuclei (AGN) luminosities, and SFRs. We find considerable differences from other low-redshift LINERs, in terms of extinction, and general similarity to star-forming galaxies. We confirm the existence of such luminous LINERs in the local universe, after being previously detected at z ˜ 0.3 by Tommasin et al. The median stellar mass of these LINERs corresponds to 6-7 × 1010 M⊙ which was found in previous work to correspond to the peak of relative growth rate of stellar populations and therefore for the highest SFRs. Other LINERs although showing similar AGN luminosities have lower SFR. We find that most of these sources have LAGN ˜ LSF suggesting co-evolution of black hole and stellar mass. In general, the fraction of local LINERs on the main sequence of star-forming galaxies is related to their AGN luminosity.

  1. Dust near luminous ultraviolet stars

    NASA Astrophysics Data System (ADS)

    Henry, Richard C.

    1992-03-01

    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-3 is placed on the equivalent gas density in the intercloud regions. The clouds have an average density of 0.22 cm-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.

  2. 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.

  3. 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

  4. An x-ray study of luminous infrared galaxies observed with ASCA

    NASA Astrophysics Data System (ADS)

    Misaki, K.; Iwasawa, K.; Taniguchi, Y.; Terashima, Y.; Kunieda, H.; Watarai, H.

    The discovery of ultra-luminous infrared galaxies (ULIRGs) has provided a clue to an evolutionary connection between starburst and active galactic nuclei. The IRAS color is suggested to be a possible trace of the evolution. We present the results of ASCA observations of two ULIRGs, IRAS20551-4250 and IRAS23128-5919, which are southern 100 μm bright galaxies with LIR ~ 1012Lsolar. Both are mergers and have a ``warm'' IRAS color (25μm100μm >= 0.15). The ASCA spectrum of IRAS20551-4250 can be characterized by two components, one of which is a soft thermal component (kT ~ 0.3keV) and the other is a hard power-law component absorbed by a column density of 1022 cm-2. The observed X-ray luminosity is ~ 2.5 × 1042 ergs/s in the rest frame 2-10keV band (assuming H0 = 50 km/s/Mpc). IRAS23128-5919 also shows a hard spectrum (LX ~ 3 × 1042 ergs/s), but thermal emission is not as clear as that in IRAS20551-4250. Since these targets are similar in infrared luminosity as well as in hard X-rays but not in soft X-rays, LIR would be associated with hard X-rays. In addition to these results, we here compare X-ray properties of ULIRGs with IR properties.

  5. High excitation emission line nebula associated with an ultra-luminous X-ray source at z = 0.027 in the AKARI North Ecliptic Pole Deep Field

    NASA Astrophysics Data System (ADS)

    Díaz Tello, J.; Miyaji, T.; Ishigaki, T.; Krumpe, M.; Ueda, Y.; Brunner, H.; Goto, T.; Hanami, H.; Toba, Y.

    2017-07-01

    Aims: We report our finding of a high excitation emission line nebula associated with an ultra-luminous X-ray source (ULX) at z= 0.027, which we found in our Chandra observation of the AKARI North Ecliptic Pole Deep Field. Methods: We present a Chandra X-ray and Gran Telescopio Canarias (GTC) optical spectral analysis of the ULX blob. We investigated the nature of the emission line nebula using line ratio diagnostic diagrams and estimated the physical properties of the nebula with spectral energy distribution (SED) fitting. Results: The optical spectrum of this ULX blob shows emission line ratios that are located on the borderlines between star formation and Seyfert regimes in [OIII]/Hβ-[OI]/Hα, [OIII]/Hβ-[SII]/Hα, and [OIII]/Hβ-[OIII]/[OII] diagnostic diagrams. These are in contrast with those of a nearby blob observed with the same slit, which occupies the HII regimes. Conclusions: This result suggests that the energy input from the accretion power of the ULX, in addition to the star formation activity in the blob, significantly contribute to the ionization of the emission line nebula associated with the ULX, suggesting the existence of an accretion disk in the ULX emitting UV radiation or exerting shock waves.

  6. 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.; hide

    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

  7. 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

  8. Ultra-luminous X-ray sources and neutron-star-black-hole mergers from very massive close binaries at low metallicity

    NASA Astrophysics Data System (ADS)

    Marchant, Pablo; Langer, Norbert; Podsiadlowski, Philipp; Tauris, Thomas M.; de Mink, Selma; Mandel, Ilya; Moriya, Takashi J.

    2017-08-01

    The detection of gravitational waves from the binary black hole (BH) merger GW150914 may enlighten our understanding of ultra-luminous X-ray sources (ULXs), as BHs of masses >30 M⊙ can reach luminosities >4 × 1039 erg s-1 without exceeding their Eddington luminosities. It is then important to study variations of evolutionary channels for merging BHs, which might instead form accreting BHs and become ULXs. It was recently shown that very massive binaries with mass ratios close to unity and tight orbits can undergo efficient rotational mixing and evolve chemically homogeneously, resulting in a compact BH binary. We study similar systems by computing 120 000 detailed binary models with the MESA code covering a wide range of masses, orbital periods, mass ratios, and metallicities. For initial mass ratios q ≡ M2/M1 ≃ 0.1-0.4, primaries with masses above 40 M⊙ can evolve chemically homogeneously, remaining compact and forming a BH without experiencing Roche-lobe overflow. The secondary then expands and transfers mass to the BH, initiating a ULX phase. At a given metallicity this channel is expected to produce the most massive accreting stellar BHs and the brightest ULXs. We predict that 1 out of 104 massive stars evolves this way, and that in the local universe 0.13 ULXs per M⊙ yr-1 of star formation rate are observable, with a strong preference for low metallicities. An additional channel is still required to explain the less luminous ULXs and the full population of high-mass X-ray binaries. At metallicities log Z> -3, BH masses in ULXs are limited to 60 M⊙, due to the occurrence of pair-instability supernovae which leave no remnant, resulting in an X-ray luminosity cut-off for accreting BHs. At lower metallicities, very massive stars can avoid exploding as pair-instability supernovae and instead form BHs with masses above 130 M⊙, producing a gap in the ULX luminosity distribution. After the ULX phase, neutron star BH binaries that merge in less than a

  9. IRAS observations of RCW 86

    NASA Astrophysics Data System (ADS)

    Greidanus, H.; Strom, R. G.

    1990-12-01

    Infrared maps and fluxes of the supernova remnant RCW 86 (MSH 14-63) were obtained from the IRAS data base, using a destripping and a spectral decomposition technique to isolate the weak IR emission of RCW 86 from all other contributions in the IRAS maps. It is shown that the IR brightness maps correlate very well with the X-ray-brightness, the optical, and the radio images. A comparison with the three other young shell-type SNRs Tycho, Kepler, and Cas A showed that the IR temperatures and luminosities of these objects decrease with age. For all objects, however, the IR- and X-ray-based densities are similar, while the X-ray-derived masses are an order of magnitude above the IR masses.

  10. HIRAS, high resolution IRAS images

    NASA Astrophysics Data System (ADS)

    Bontekoe, Tj. R.; Kester, D. J. M.; Wesselius, P. R.

    The IRAS Software Telescope allows everyone to obtain the state-of-the-art IRAS products (survey, pointed observations, as well as low-resolution spectra) from raw uncalibrated scan data to FITS maps and any stage in between, any size area up to five by five degree, within 24 hours response time, and without the tedious proposal and refereeing process. This is done via an electronic mail server, without manual interaction. High Resolution Images can also be made by running HIRAS, which drives the MemSys5 (Gull & Skilling 1991) maximum entropy package. Herewith a resolution of order one arc-minute, instead of the usual five arc-minutes, can be obtained.

  11. The Duplicity of IRAS 16293-2422: A Protobinary Star?

    NASA Astrophysics Data System (ADS)

    Wootten, Alwyn

    1989-02-01

    Continuum maps at wavelengths of 6 cm and 2 cm of the region surrounding the infrared object IRAS 16293-2422 reveal two related sources, A and B separated by ˜5" (750 AU) along P.A. -50°. These sources lie within the 3 mm continuum source mapped by Mundy, Wilking, and Myers, which located density maxima of the dust disk at the core of the surrounding L1689N molecular cloud. Both the A and B sites of centimeter wave emission probably arise from ionized gas associated with distinct sites of star formation within this dense core. Thus IRAS 16293-2422 presents a rare opportunity to observe a binary system in its earliest stages of formation. Higher resolution maps reveal that the brighter source, IRAS 16293- 2422A, is comprised of two unresolved sources, Al and A2, separated by 47 AU in projected distance, approximately perpendicular to the line between the more widely separated objects. A modest velocity-segregated cluster of water masers identifies these sources as associated with a bipolar flow, which must be collimated on a scale smaller than 50 AU. The ionized gas apparently exists as a trace constituent in a region where magnetohydrodynamic shocks impinging on the ambient cloud excite maser emission. Several arguments suggest that object B is less evolved than object A, and may be in a prestellar phase of its evolution. Interaction of the cores containing these objects may explain the complex pattern of the bipolar flow mapped by Wootten and Loren.

  12. 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.

  13. 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

  14. 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.

  15. The times of Ira Hirsh

    NASA Astrophysics Data System (ADS)

    Divenyi, Pierre L.

    2002-05-01

    Ira Hirsh was among the first to recognize that the auditory system does not deal with temporal information in a unitary way across the continuum of time intervals involved in speech processing. He identified the ``short'' range (extending from 1 to 20 ms) as that of phase perception, the ``medium'' range between 20 and 100 ms as that in which auditory patterns emerge, and the ``long'' range from 100 ms on as that of separate auditory events. Further, he was also among the first to recognize that auditory time perception heavily depended on the spectral context. A study of the perception of sequences representing different temporal orders of three tones, by Ira and the author [e.g., Divenyi and Hirsh, J. Acoust. Soc. Am. 64, 1369-1385 (1978)] demonstrated the dependence of auditory sequence perception on both time range and spectral context, and provided a bridge between Hirsh's view of auditory time and Bregman's view of stream segregation [Auditory Scene Analysis (MIT Press, Cambridge, MA, 1991)]. A subsequent search by the author for psychophysical underpinnings of the cocktail-party phenomenon [e.g., Divenyi et al., Moh. Mtn. Workshop Appl. SPAA (IEEE, Bellingham, WA, 1997)] suggest that the segregation of simultaneous streams of speech may rely on the ability to follow spectral changes in the demisyllabic-to-syllabic (100- to 200-ms) range, i.e., Ira's ``long'' range.

  16. IRA balances and contributions: an overview of the EBRI IRA database.

    PubMed

    Copeland, Craig

    2010-09-01

    NEW IRA DATABASE: The Employee Benefit Research Institute created the EBRI IRA Database in order to more closely examine retirement savings behavior. The EBRI IRA Database is able to link individuals within and across the data providers and will also be able to link the data with participants in 401(k) plans, allowing retirement funds to be tracked as they are generated, rolled over, and ultimately used. This Issue Brief is the first of a series of publications analyzing the EBRI IRA Database, and highlights the distribution of IRA owners by IRA type, average and median account balances, and contributions to IRAs. The data security techniques used by the data providers assure that EBRI has no ability to identify individuals so that all privacy is assured. IRA TYPES: In the EBRI IRA Database, IRAs are classified into four types: traditional (originating from contributions), rollovers from other retirement plans, Roth, and SEP/SIMPLE. The distribution of the IRA accounts is 33.6 percent traditional IRAs; 33.4 percent rollover IRAs (combined with the traditional IRAs, 67 percent); 23.4 percent Roth IRAs; the remaining 9.6 percent are SEPs and SIMPLEs. OWNERSHIP BY AGE AND GENDER: IRA owners were more likely to be male, especially those having a rollover or a SEP/SIMPLE IRA. Among all IRA participants in the database, nearly one-half (48.3 percent) were ages 45-64. Only 16.7 percent of those owning a traditional IRA were under age 45, compared with 46.5 percent for those with a Roth, 30.4 percent for rollovers, and 34.8 percent for those with a SEP or SIMPLE. AVERAGE AND MEDIAN BALANCES: The average and median IRA account balance in 2008 was $54,863 and $15,756, respectively, while the average and median IRA individual balance (all accounts from the same person combined) was $69,498 and $20,046, Individuals with a rollover balance had the highest average and median balance at $91,783 and $31,264. Roth owners had the lowest average and median balance at $14,056 and $7

  17. THE ROTATING MOLECULAR STRUCTURES AND THE IONIZED OUTFLOW ASSOCIATED WITH IRAS 16547-4247

    SciTech Connect

    Franco-Hernandez, Ramiro; Moran, James M.; RodrIguez, Luis F.; Garay, Guido

    2009-08-20

    We present Very Large Array 1.3 cm radio continuum and water maser observations as well as Submillimeter Array SO{sub 2} (226.300 GHz) and 1.3 mm dust continuum observations toward the massive star formation region IRAS 16547-4247. We find evidence of multiple sources in the central part of the region. There is evidence of a rotating structure associated with the most massive of these sources, traced at small scales ({approx}50 AU) by the water masers. At large scales ({approx}1000 AU), we find a velocity gradient in the SO{sub 2} molecular emission with a barely resolved structure that can be modeled as a rotating ring or two separate objects. The velocity gradients of the masers and of the molecular emission have the same sense and may trace the same structure at different size scales. The position angles of the structures associated with the velocity gradients are roughly perpendicular to the outflow axis observed in radio continuum and several molecular tracers. We estimate the mass of the most massive central source to be around 30 solar masses from the velocity gradient in the water maser emission. The main source of error in this estimate is the radius of the rotating structure. We also find water masers that are associated with the large-scale molecular outflow of the system, as well as water masers that are associated with other sources in the region. Our results suggest that the formation of this source, one of the most luminous protostars or protostellar clusters known, is taking place with the presence of ionized jets and disk-like structures.

  18. Coexistence of a non-thermal jet and a complex ultra-fast X-ray outflow in a moderately luminous AGN

    NASA Astrophysics Data System (ADS)

    Giroletti, M.; Panessa, F.; Longinotti, A. L.; Krongold, Y.; Guainazzi, M.; Costantini, E.; Santos-Lleo, M.

    2017-04-01

    Context. Recent XMM-Newton observations have revealed that IRAS 17020+4544 is a very unusual example of black hole wind-produced feedback by a moderately luminous AGN in a spiral galaxy. Aims: Since the source is known to be a radio emitter, we investigated the presence and the properties of a non-thermal component. Methods: We observed IRAS 17020+4544 with the Very Long Baseline Array at 5, 8, 15, and 24 GHz within a month of the 2014 XMM-Newton observations. We further analysed archival data taken in 2000 and 2012. Results: We detect the source at 5 GHz and on short baselines at 8 GHz. At 15 and 24 GHz, the source is below our baseline sensitivity for fringe fitting, indicating a lack of prominent compact features. The morphology is that of an asymmetric double, with significant diffuse emission. The spectrum between 5 and 8 GHz is rather steep (S(ν) ν- (1.0 ± 0.2)). Our reanalysis of the archival data at 5 and 8 GHz provides results consistent with the new observations, suggesting that flux density and structural variability are not important in this source. We put a limit on the separation speed between the main components of <0.06c. Conclusions: IRAS 17020+4544 shows interesting features of several classes of objects: its properties are typical of compact steep spectrum sources, low power compact sources, and radio-emitting narrow line Seyfert 1 galaxies. However, it cannot be classified in any of these categories, and remains a one-of-a-kind object. Reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/A87 .

  19. IRAS observations of extended zodiacal structures

    NASA Technical Reports Server (NTRS)

    Sykes, Mark V.

    1988-01-01

    In 1983, the Infrared Astronomical Satellite discovered two pairs of dust bands, straddling the ecliptic plane and located in the asteroid belt. New analysis of the IRAS data has resulted in the detection of as many as eight additional bands, spread over more than 40 deg of ecliptic latitude. Dust band morphology is found to vary between different band pairs, having a typical apparent width of a few degrees. This limits the total number of bands which can be distinguished to near the number observed. The Tempel 2 and Encke dust trails are observed to extend over much more of their orbits than had been previously reported, and a new type of dust trail is found which has a relatively large angular width and no imbedded cometary source.

  20. 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.

  1. Constraints on the optical polarization source in the luminous non-blazar quasar 3C 323.1 (PG 1545+210) from the photometric and polarimetric variability

    NASA Astrophysics Data System (ADS)

    Kokubo, Mitsuru

    2017-01-01

    We examine the optical photometric and polarimetric variability of the luminous type 1 non-blazar quasar 3C 323.1 (PG 1545+210). Two optical spectro-polarimetric measurements taken during the periods 1996-98 and 2003 combined with a V-band imaging polarimetric measurement taken in 2002 reveal that (1) as noted in the literature, the polarization of 3C 323.1 is confined only to the continuum emission, that is, the emission from the broad line region is unpolarized; (2) the polarized flux spectra show evidence of a time-variable broad absorption feature in the wavelength range of the Balmer continuum and other recombination lines; (3) weak variability in the polarization position angle (PA) of ˜ 4 deg over a time-scale of 4-6 years is observed; and (4) the V-band total flux and the polarized flux show highly correlated variability over a time-scale of one year. Taking the above-mentioned photometric and polarimetric variability properties and the results from previous studies into consideration, we propose a geometrical model for the polarization source in 3C 323.1, in which an equatorial absorbing region and an axi-asymmetric equatorial electron-scattering region are assumed to be located between the accretion disc and the broad line region. The scattering/absorbing regions can perhaps be attributed to the accretion disc wind or flared disc surface, but further polarimetric monitoring observations for 3C 323.1 and other quasars with continuum-confined polarization are needed to probe the true physical origins of these regions.

  2. Constraints on the optical polarization source in the luminous non-blazar quasar 3C 323.1 (PG 1545+210) from the photometric and polarimetric variability

    NASA Astrophysics Data System (ADS)

    Kokubo, Mitsuru

    2017-05-01

    We examine the optical photometric and polarimetric variability of the luminous type 1 non-blazar quasar 3C 323.1 (PG 1545+210). Two optical spectropolarimetric measurements taken during the periods 1996-1998 and 2003 combined with a V-band imaging-polarimetric measurement taken in 2002 reveal that (1) as noted in the literature, the polarization of 3C 323.1 is confined only to the continuum emission, i.e. the emission from the broad-line region is unpolarized; (2) the polarized flux spectra show evidence of a time-variable broad absorption feature in the wavelength range of the Balmer continuum and other recombination lines; (3) weak variability in the polarization position angle (PA) of ˜4°over a time-scale of 4-6 yr is observed and (4) the V-band total flux and the polarized flux show highly correlated variability over a time-scale of 1 yr. Taking the above-mentioned photometric and polarimetric variability properties and the results from previous studies into consideration, we propose a geometrical model for the polarization source in 3C 323.1, in which an equatorial absorbing region and an axi-asymmetric equatorial electron-scattering region are assumed to be located between the accretion disc and the broad-line region. The scattering/absorbing regions can perhaps be attributed to the accretion disc wind or flared disc surface, but further polarimetric monitoring observations for 3C 323.1 and other quasars with continuum-confined polarization are needed to probe the true physical origins of these regions.

  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. The Most Luminous Galaxies Found by WISE

    NASA Astrophysics Data System (ADS)

    Eisenhardt, Peter

    2012-08-01

    We have used photometry from NASA's Wide-field Infrared Survey Explorer (WISE) to select an all-sky sample of objects which are extremely luminous. Herschel far-IR follow-up observations of these sources are underway. We find most are brighter than 10 trillion solar luminosities, and about 10% exceed 100 trillion solar luminosities. We request one night with LRIS-ADC to obtain redshifts for 20 candidate WISE Ultra-Luminous IR Galaxies which are targets of the Herschel program. The redshifts are essential to one of the two primary science objectives for WISE: to identify the most luminous galaxies in the Universe.

  6. 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).

  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. 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.

  9. 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.

  10. 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

  11. High-sensitivity IRAS observations of the Chamaeleon I dark cloud

    NASA Technical Reports Server (NTRS)

    Baud, B.; Beintema, D. A.; Wesselius, P. R.; Young, E.; Beichman, C. A.; Emerson, J. P.; Harris, S.; Habing, H. J.; Jennings, R. E.; Marsden, P. L.

    1984-01-01

    Very sensitive IRAS observations of a region of 0.8 sq deg in the Chamaeleon I cloud have revealed 70 compact sources. Hot sources are field stars; warm sources are associated with pre-main-sequence (PMS) stars in the cloud center; others may be in an even earlier phase of gravitational collapse. Cool sources, detected only at the long wavelengths, surround the main cloud and appear to be associated with small globules. Only a small fraction (less than 20 percent) of the total luminosity of the known PMS objects is emitted in the IRAS bands. This has important implications for the classification of the newly discovered embedded objects.

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

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Wainscoat, Richard J.; Walker, Helen J.; Volk, Kevin; Schwartz, Deborah E.

    1989-01-01

    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.

  13. 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.

  14. Infrared and Submillimeter Observations Of IRAS 03245+3002

    NASA Astrophysics Data System (ADS)

    Doney, Kirstin D.; Kim, H.; Evans, N. J.

    2012-01-01

    We present a study of a young stellar object in the embedded phase, IRAS 03245+3002, which is part of the Dust, Ice, and Gas In Time (DIGIT) project which is designed to span the full range Lbol-Tbol diagram. The Spitzer Space Telescope and ground-based telescopes, 2MASS and CSO, have observed the object in the infrared and submillimeter wavelengths. The photometric data give constraints on the radiative transfer modeling and give an bolometric luminosity of 4.6L⊙. We also present the molecular line observations of six species toward IRAS 03245+3002 taken at CSO, the molecular line modeling, of which are still on going, will give an expectation of the molecular abundances of the source and will be presented in the poster. I would like to acknowledge Dr. Neal J. Evans II, Hyo Jeong Kim, and the University of Texas at Austin for their help and support.

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

    NASA Astrophysics Data System (ADS)

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

    1989-05-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Establishing Roth IRAs. 1.408A-2 Section 1.408A... Roth IRAs. This section sets forth the following questions and answers that provide rules applicable to establishing Roth IRAs: Q-1. Who can establish a Roth IRA? A-1. Except as provided in A-3 of this section,...

  18. 26 CFR 1.408A-2 - Establishing Roth IRAs.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Establishing Roth IRAs. 1.408A-2 Section 1.408A... Roth IRAs. This section sets forth the following questions and answers that provide rules applicable to establishing Roth IRAs: Q-1. Who can establish a Roth IRA? A-1. Except as provided in A-3 of this section,...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Establishing Roth IRAs. 1.408A-2 Section 1.408A... Roth IRAs. This section sets forth the following questions and answers that provide rules applicable to establishing Roth IRAs: Q-1. Who can establish a Roth IRA? A-1. Except as provided in A-3 of this section,...

  20. 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.

  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 ([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.

  2. 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

  3. 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.

  4. CO detections and IRAS observations of bright radio spiral galaxies at cz equal or less than 9000 kilometers per second

    NASA Technical Reports Server (NTRS)

    Sanders, D. B.; Mirabel, I. F.

    1985-01-01

    CO emission has been detected from 20 of 21 bright radio spirals with strong extended nuclear sources, including the most distant (NGC 7674) and the most luminous (IC 4553 = Arp 220, NGC 6240) galaxies yet detected in CO. All of these galaxies are rich in molecular gas, with M total(H2) = 3 x 10 to the 8th - 2 x 10 to the 10th solar masses. IRAS observations show that they have a strong far-infrared (FIR) excess, with L(FIR)/L(B) approximately equal to 1-35 and L(FIR) (40-400 microns) approximately equal to 10 to the 10th - 10 to the 12th L solar masses. The primary luminosity source for these radio cores appears to be star formation in molecular clouds. A strong correlation is found between the FIR and extended 21 cm continuum flux, implying that the fraction of massive stars formed is independent of the star formation rate. The ratio L(FIR)/M(H2) provides a measure of the current rate of star formation, which is found to be a factor 3-20 larger in these galaxies than for the ensemble of molecular clouds in the Milky Way. At these rates their molecular gas will be depleted in about 10 to the 8th yr.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. IRAS low resolution spectra of 26 symbiotic stars

    NASA Technical Reports Server (NTRS)

    Stencel, Robert E.; Brugel, Edward W.; Goodwill, Michael E.

    1990-01-01

    Data related to the spectral scans for 26 symbiotic stars are described which were extracted from the IRAS low resolution database. Data from the 8-15- and 15-23-micron bands are merged in a program that scales the longer wavelength and produces a weighted average of the spectral scans for each source. The survey shows that active dust producers can probably be isolated and some theories related to the presence of dust emission features are discussed in terms of source variability for measurements made with low resolution spectra.

  11. 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.

  12. A Radio Study of the Ultra-luminous FIR Galaxy NGC 6240

    NASA Astrophysics Data System (ADS)

    Colbert, E.; Wilson, A. S.; Bland-Hawthorn, J.

    1993-05-01

    A number of galaxies observed in the IRAS mission are noted to emit ~ 99% of their bolometric flux in the FIR, with FIR luminosities in excess of 10(11) Lsun. The interacting galaxy NGC 6240 has often been referred to as the ``proto-typical'' ultra-luminous (L_FIR >~ 10(12) Lsun) FIR galaxy. The origin of the FIR excess remains a disputed subject in the literature. New observations of NGC 6240 were taken with the VLA at 20cm in the B-configuration, and at 3.6cm in the A-configuration. No significant radio emission was detected from or near the possible ultra-massive ``dark core'' hypothesized by Bland-Hawthorn et. al. (1991); however, approximately 30% of Seyfert galaxies have 20 cm radio luminosities weaker than the upper limit derived from the radio maps. The non-thermal radio emission from luminous FIR galaxies is tightly correlated with the FIR emission. Previous radio observations of NGC 6240 revealed two compact, steep-spectrum nuclear sources, nearly coincident with the two nuclear sources seen in optical images. The 2 images from the new VLA observations and 5 images from previous VLA observations are used to identify the morphological and spectral features of the strong, compact components in the nuclear regions (<~ 1.5 kpc; D=100 Mpc) and of the weaker ``clumps'' of diffuse emission south and west (>~ 3 kpc) from the nucleus. Feasible explanations for the radio emission are discussed. The models that have been proposed in the literature for the FIR excess of NGC 6240 are evaluated for consistency with the observed radio emission.

  13. 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

  14. Small grains and IRAS colors

    NASA Technical Reports Server (NTRS)

    Boulanger, F.; Beichman, C.; Helou, G.; Desert, F. X.; Perault, M.

    1988-01-01

    The paper studies how infrared colors of dust emission from the interstellar medium vary with the energy density of the radiation field on the basis of IRAS observation of the California Nebula. The data suggest that color variations result from a combinatin of equilibrium emission from large grains, and nonequilibrium emission from small grains, with destruction of the small grains emitting at 12 microns at high energy density; it is estimated that 80 percent of these small particles are destroyed for an energy density in ultraviolet photons larger than 50 times that of the average interstellar radiation field in the solar neighborhood. In a color-color diagram, I(v)(60 microns)/I(v)(100 microns) versus I(v)(12 microns)/I(v)(25 microns), the California Nebula measurements at various distances to the ionizing star Zeta Per follow a sequence similar to that of galaxies. This result shows that the position of a galaxy along this sequence is a measure of the intensity of the radiation field in the regions responsible for the infrared emission.

  15. 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.

  16. THE TOTAL LUMINOUS EFFICIENCY OF LUMINOUS BACTERIA

    PubMed Central

    Harvey, E. Newton

    1925-01-01

    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. O2 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

  17. Further radio observations of IRAS extreme infrared galaxies

    NASA Astrophysics Data System (ADS)

    Antonucci, R. R. J.; Olszewski, E. W.

    1986-01-01

    Aaronson and Olszewski (1984) have identified five IRAS infrared sources, previously considered to be blank fields, with faint galaxies. The authors reported previously the results of their VLA D-array observations at 6 cm (Antonucci and Olszewski, 1985), which resulted in detections of all objects at the mJy level. The sources were unresolved by the ≡16 arcsec beam. The present paper reports on B-array observations at 6 and 20 cm, made in order to determine or limit the source angular sizes, and to measure the spectral indices. The source 0358+223 has an angular size of ≡3 arcsec at 20 cm, but no redshift is available for this object; also 0404+101 is marginally resolved at 20 cm. The other sources are unresolved by the ≡1.1 arcsec resolution deep 6 cm maps, implying linear sizes <2 kpc. The spectra are steep, indicating that the radiation mechanism is optically thin synchrotron emission.

  18. 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.

  19. 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.

  20. 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.

  1. Perspective view, northeast, of Ira Allen Chapel on the campus ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view, northeast, of Ira Allen Chapel on the campus of the University of Vermont. This Colonial Revival chapel was designed by McKim, Mead, and White in 1925. - Ira Allen Chapel, 26 University Place, Burlington, Chittenden County, VT

  2. 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.

  3. 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.

  4. IRAS 21391 + 5802 - A study in intermediate mass star formation

    NASA Technical Reports Server (NTRS)

    Wilking, Bruce; Mundy, Lee; Mcmullin, Joseph; Hezel, Thomas; Keene, Jocelyn

    1993-01-01

    We present infrared and millimeter wavelength observations of the cold IRAS source 21391 + 5802 and its associated molecular core. Infrared observations at lambda = 3.5 microns reveal a heavily obscured, central point source which is coincident with a compact lambda = 2.7 mm continuum and C18O emission region. The source radiates about 310 solar luminosities, primarily at FIR wavelengths, suggesting that it is a young stellar object of intermediate mass. The steeply rising spectral energy distribution and the large fraction of the system mass residing in circumstellar material imply that IRAS 21391 + 5802 is in an early stage of evolution. The inferred dust temperature indicates a temperature gradient in the core. A comprehensive model for the surrounding core of dust and gas is devised to match the observed dust continuum emission and multitransition CS emission from this and previous studies. We find a r exp -1.5 +/- 0.2 density gradient consistent with that of a gravitationally evolved core and a total core mass of 380 solar masses. The observed dust emission is most consistent with a lambda exp -1.5 - lambda exp -2 dust emissivity law; for a lambda exp -2 law, the data are best fit by a mass opacity coefficient of 3.6 x 10 exp -3 sq cm/g at lambda = 1.25 mm.

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

    NASA Astrophysics Data System (ADS)

    Imanishi, Masatoshi; Nakanishi, Kouichiro; Izumi, Takuma

    2016-12-01

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

  6. IRAS cryogenic system flight performance report

    NASA Technical Reports Server (NTRS)

    Urbach, A. R.; Mason, P. V.

    1984-01-01

    It is pointed out that the Infrared Astronomical Satellite (IRAS) is the first telescope to perform observations in the far infrared from orbit. IRAS was launched on January 25, 1983 into a 900 km orbit. The use of the first large superfluid helium dewar in space makes it possible to provide a 2 K telescope environment for an anticipated period of one year. A description of the cryogenic system of IRAS is presented, taking into account the superfluid helium tank, the insulation system, the vacuum shell, the aperture cover, and the fluid management system. The dynamic performance of the cryogenic system is considered along with aspects of prelaunch preparations. Details of flight performance are also discussed, giving attention to transient performance, and steady state performance.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Infrared Polarization of the Molecular Cloud Associated to IRAS 18236-1205

    NASA Astrophysics Data System (ADS)

    Luna, A.; Retes, R.; Devaraj, R.; Maya, Y. D.; Carrasco, L.

    2017-07-01

    We present the near-infrared polarization observations towards the star forming molecular cloud associated with the IRAS source 18236-1205, obtained with the near-infrared (NIR) imaging polarimeter POLICAN at the Guillermo Haro Astrophysical Observatory in Cananea, Sonora, México.

  12. An analysis of a full sky redshift survey of IRAS galaxies

    NASA Astrophysics Data System (ADS)

    Fisher, Karl Booth

    1992-01-01

    Results are presented from an all-sky redshift survey of 5307 galaxies extracted from the Infrared Astronomical Satellite (IRAS) Point Source Catalog. The analysis presented in this thesis focuses on the spatial distribution and clustering of IRAS galaxies in this survey. We present an in-depth analysis of the possibility of density evolution in the catalogue. We conclude that the 1.2 Jy IRAS survey is consistent with no evolution, if the comoving density of galaxies is characterized as evolving proportional to (1 + z)alpha, we find alpha = 2 +/- 3, where the quoted error includes both random and systematic components. The random errors in alpha, of order 2, arise primarily from counting statistics, and are comparable to those found by previous authors. We discuss a variety of important random and systematic errors which decrease the certainty with which we can measure evolution: limited knowledge of the cosmological model, the unknown intrinsic spectral energy distribution of IRAS galaxies from 16 to 140 mu m, the effect of density fluctuations, a Malmquist-like bias arising from flux errors in the parent IRAS Point Source Catalog, and possible incompleteness of the sample at high redshifts and low Galactic latitudes. We show that the Malmquist bias could result in a significant overestimation of the evolution rate, especially if the catalog has a flux limit near the completion limit of the Point Source Catalog. We examine the two-point correlation function of the sample in both real and redshift space. The redshift space correlation function, xi(s), is shown to be robust and independent of the depth of the sample in which it is computed. We have also computed the Fourier conjugate of the correlation function, the power spectrum of galaxy clustering, P(k), for the 1.2 Jy IRAS survey using a window function which minimizes the aliasing due to the sample boundaries. We compare the IRAS power spectrum qualitatively with a variety of theoretical models, and conclude

  13. IRASLRS -- Obtaining Spectra from the IRAS LRS Database

    NASA Astrophysics Data System (ADS)

    Walker, H.; Giaretta, D.

    The IRAS LRS (Low Resolution Spectrograph) database contains about 170,000 spectra for about 40,000 sources. The LRS Atlas contains the ``best'' averaged spectra for 5425 sources, so there are a lot of new spectra; some good, some rubbish. The LRS operates from around 7$mum to 24mum, using a blue and red channel, with some overlap around 12mum to 13mum. There are 100 sample points in each channel. The LRS is a slitless spectrograph, so extended sources and multiple sources confuse the blue and the red channels. During the IRAS mission, whenever a sufficiently bright point source triggered the algorithm, the spectrum was extracted from the LRS datastream and stored in the LRS dataset. This means that, although the source may not be in the Point Source Catalog (but in the Rejects file) the spectra are still in the dataset. The program to average the spectra, and output them, started life as a batch program on an old IBM main-frame. Parts of this program are the original pieces used to create the LRS Atlas, and by setting flags appropriately you could recreate the Atlas. The original program was written by E. Raimond, F. Olnon, K. Lugtenberg. The program was modified to run ``interactively'' on a Vax (at Groningen) by P. te Lintel, and he added a radio astronomy plotting package, POPS, to it. The present copy was sent to H. Walker (at NASA Ames) by P. Wesselius, and now, having been loaded onto STADAT, the Ames command procedures have been modified by D. Giaretta. This warns you that the package is fragile, and temperamental. There is a complete user manual available, in the [iraslrs] directory.

  14. Luminous pulses during triggered lightning

    NASA Astrophysics Data System (ADS)

    Winn, W. P.; Eastvedt, E. M.; Trueblood, J. J.; Eack, K. B.; Edens, H. E.; Aulich, G. D.; Hunyady, S. J.; Murray, W. C.

    2012-05-01

    A triggered lightning flash that transferred negative charge to ground in central New Mexico produced more than three levels of branching above the main channel to ground in a 1 km vertical field of view. A high-speed video recording shows that the main channel had about 50 brief luminous pulses, many of which were superimposed on a slowly changing persistent luminosity. In contrast, superposition was rare in the uppermost visible branches because luminous pulses first appeared on preexisting dark channels before merging into a luminous channel. This observation suggests that luminous pulses in triggered and natural lightning originate only on dark branches and that the complexity of the main channel to ground is the result of multiple mergers of dark branches with pulses into luminous branches without pulses. This suggestion is contrary to an earlier conclusion that there are two kinds of luminous pulses. We also observe behavior characteristic of electromagnetic waves on transmission lines: when a downward propagating luminous pulse reaches a junction with another initially dark branch, it travels both upward and downward along that branch. Upon reaching the ground the downward propagating wave produces a bright reflection which also splits at the junctions, producing luminosity for a short distance upward in one direction while propagating much farther upward along the path charged by the downward propagating wave. However, when a downward moving luminous pulse reaches a junction with an initially luminous branch, splitting is not evident, probably due to the greater conductivity of the luminous channel.

  15. 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.

  16. On the calibration of the IRAS low-resolution spectra

    NASA Technical Reports Server (NTRS)

    Volk, Kevin; Cohen, Martin

    1989-01-01

    The need for corrections to the LRS spectra based on a study of a number of normal stars observed by IRAS is discussed. The spectra of bright stars, such as alpha CMa, were found to be inconsistent with blackbody sources, this effect being generally observed in sources earlier than about K3. An attempt is made to correct the LRS spectra by changing the blackbody calibration temperature for Alpha Tau, assumed to be a 10,000-K blackbody source for the original LRS flux calibration. It is found that an anomalously low color temperature must be assumed for alpha Tau to produce reasonable results for earlier-type stars. Corrections based on a set of stars with well-determined effective temperatures are examined, as are the resulting color temperatures for 72 stars with Atlas spectra.

  17. Ira P. Gunn: educator, advocate, legend.

    PubMed

    McAuliffe, Maura S; Koch, Faan Kathy J

    2011-12-01

    This column examines the contributions of nurse anesthetist Ira P. Gunn, CRNA, MLN, FAAN (1927-2011), widely recognized as a visionary and tireless advocate for the profession of nurse anesthesia. Her contributions to nurse anesthesia practice, research, education, publication, consultation, credentialing, and government relations have significantly contributed to the preservation and advancement of nursing and nurse anesthesia.

  18. 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.

  19. A redshift survey of IRAS galaxies

    NASA Astrophysics Data System (ADS)

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

    1987-05-01

    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-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.

  20. 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.

  1. 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.

  2. The Interstellar Bullet Engine IRAS 05506+2414

    NASA Technical Reports Server (NTRS)

    Stantzos, Nicholas W.; Sahai, Raghvendra

    2011-01-01

    Throughout their life-cycles, high-mass stars inject large amounts of energy and momentum into theirenvironments through stellar winds. Results from a study of the Orion BN/KL region indicate that disruption of a massive young stellar system can lead to an explosive event producing a wide-angle outflow, different from the classical bipolar flows driven by young stellar object (YSO) accretion disks. The discovery of a massive YSO, IRAS 05506+2414, may prove to be the second instance of this uncommon outflow. Prior to this study, data was collected using the Arizona Radio Observatory's 10-meter and 12-meter telescopes. Spectra of 16 different molecular line transitions were organized, reduced, and prepared for further analysis. A variety of molecular transitions were observed, such as 12CO 2-1, HCO+ 3-2, CS 3-2, in order to probe physical conditions of the YSO. From line transitions like HCO+ 3-2, we will determine physical properties like density, temperature, and velocity of our source object. For each molecular transition, the spectra were averaged in subsets, which were then averaged to produce a final spectra with an optimal signal to noise ratio. Future radiative modeling will yield mass and energetics of IRAS05506+2414.

  3. 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.

  4. 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

  5. A Tale of Three Galaxies: Anomalous Dust Properties in IRAS F10398+1455, IRAS F21013-0739, and SDSS J0808+3948

    NASA Astrophysics Data System (ADS)

    Xie, Yanxia; Hao, Lei; Li, Aigen

    2014-10-01

    On a galactic scale, the 9.7 μm silicate emission is usually only seen in type 1 active galactic nuclei (AGNs). They usually also display a flat emission continuum at ~5-8 μm and the absence of polycyclic aromatic hydrocarbon (PAH) emission bands. In contrast, starburst galaxies, luminous infrared (IR) galaxies, and ultraluminous IR galaxies exhibit a red 5-8 μm emission continuum, strong 9.7 μm and 18 μm silicate absorption features, and strong PAH emission bands. Here, we report the detection of anomalous dust properties by the Spitzer/Infrared Spectrograph in three galaxies (IRAS F10398+1455, IRAS F21013-0739, and SDSS J0808+3948) which are characterized by the simultaneous detection of a red 5-8 μm emission continuum, the 9.7 and 18 μm silicate emission features, as well as strong PAH emission bands. These apparently contradictory dust IR emission properties are discussed in terms of iron-poor silicate composition, carbon dust deficit, small grain size, and low dust temperature in the young AGN phase of these three galaxies.

  6. 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

  7. 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.

  8. 26 CFR 1.408(q)-1 - Deemed IRAs in qualified employer plans.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the requirements applicable to Roth IRAs under section 408A, the account or annuity is deemed to be a Roth IRA. Simplified employee pensions (SEPs) under section 408(k) and SIMPLE IRAs under section 408(p... traditional and Roth IRAs may be imposed on distributions from deemed IRAs (for example, early...

  9. 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

  10. 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.

  11. Higher order correlations of IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Meiksin, Avery; Szapudi, Istvan; Szalay, Alexander

    1992-01-01

    The higher order irreducible angular correlation functions are derived up to the eight-point function, for a sample of 4654 IRAS galaxies, flux-limited at 1.2 Jy in the 60 microns band. The correlations are generally found to be somewhat weaker than those for the optically selected galaxies, consistent with the visual impression of looser clusters in the IRAS sample. It is found that the N-point correlation functions can be expressed as the symmetric sum of products of N - 1 two-point functions, although the correlations above the four-point function are consistent with zero. The coefficients are consistent with the hierarchical clustering scenario as modeled by Hamilton and by Schaeffer.

  12. 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.

  13. 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).

  14. 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.

  15. 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).

  16. 26 CFR 1.408A-2 - Establishing Roth IRAs.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Establishing Roth IRAs. 1.408A-2 Section 1.408A-2...) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-2 Establishing Roth... establishing Roth IRAs: Q-1. Who can establish a Roth IRA? A-1. Except as provided in A-3 of this section,...

  17. NuSTAR discovery of a young, energetic pulsar associated with the luminous gamma-ray source HESS J1640–465

    SciTech Connect

    Gotthelf, E. V.; Halpern, J. P.; Hailey, J. C.; Tomsick, J. A.; Boggs, S. E.; Craig, W. W.; Gelfand, J. D.; Harrison, F. A.; Christensen, F. E.; Kaspi, V. M.; Stern, D. K.; Zhang, W. W.

    2014-06-20

    We report the discovery of a 206 ms pulsar associated with the TeV γ-ray source HESS J1640–465 using the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray observatory. PSR J1640–4631 lies within the shell-type supernova remnant (SNR) G338.3–0.0, and coincides with an X-ray point source and putative pulsar wind nebula (PWN) previously identified in XMM-Newton and Chandra images. It is spinning down rapidly with period derivative P-dot = 9.758(44) × 10{sup –13}, yielding a spin-down luminosity E-dot = 4.4 × 10{sup 36} erg s{sup –1}, characteristic age τ{sub c}≡P/2 P-dot = 3350 yr, and surface dipole magnetic field strength B{sub s} = 1.4 × 10{sup 13} G. For the measured distance of 12 kpc to G338.3–0.0, the 0.2-10 TeV luminosity of HESS J1640–465 is 6% of the pulsar's present E-dot . The Fermi source 1FHL J1640.5–4634 is marginally coincident with PSR J1640–4631, but we find no γ-ray pulsations in a search using five years of Fermi Large Area Telescope (LAT) data. The pulsar energetics support an evolutionary PWN model for the broadband spectrum of HESS J1640–465, provided that the pulsar's braking index is n ≈ 2, and that its initial spin period was P {sub 0} ∼ 15 ms.

  18. NuSTAR Discovery Of A Young, Energetic Pulsar Associated with the Luminous Gamma-Ray Source HESS J1640-465

    NASA Technical Reports Server (NTRS)

    Gotthelf, E. V.; Tomsick, J. A.; Halpern, J. P.; Gelfand, J. D.; Harrison, F. A.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Hailey, J. C.; Kaspi, V. M.; Stern, D. K.; Zhang, W. W.

    2014-01-01

    We report the discovery of a 206 ms pulsar associated with the TeV gamme-ray source HESS J1640-465 using the Nuclear Spectroscopic Telescope Array (NuSTAR) X-ray observatory. PSR J1640-4631 lies within the shelltype supernova remnant (SNR) G338.3-0.0, and coincides with an X-ray point source and putative pulsar wind nebula (PWN) previously identified in XMM-Newton and Chandra images. It is spinning down rapidly with period derivative P = 9.758(44) × 10(exp -13), yielding a spin-down luminosity E = 4.4 × 10(exp 36) erg s(exp -1), characteristic age tau(sub c) if and only if P/2 P = 3350 yr, and surface dipole magnetic field strength B(sub s) = 1.4×10(exp 13) G. For the measured distance of 12 kpc to G338.3-0.0, the 0.2-10 TeV luminosity of HESS J1640-465 is 6% of the pulsar's present E. The Fermi source 1FHL J1640.5-4634 is marginally coincident with PSR J1640-4631, but we find no gamma-ray pulsations in a search using five years of Fermi Large Area Telescope (LAT) data. The pulsar energetics support an evolutionary PWN model for the broadband spectrum of HESS J1640-465, provided that the pulsar's braking index is n approximately equal to 2, and that its initial spin period was P(sub 0) approximately 15 ms.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. Detection of H I, OH, CO, and optical imaging of the distant galaxy IRAS 12112 + 0305

    NASA Technical Reports Server (NTRS)

    Mirabel, I. F.; Kazes, I.; Sanders, D. B.

    1988-01-01

    The detection of H I absorption and OH and CO emission from the galaxy IRAS 12112 + 0305, which is receding from the sun at about 7 percent of the speed of light is reported. This galaxy, which appears to be an ongoing merger, radiates about 2 x 10 to the 12th solar luminosities in the infrared. The H I, OH, and CO spectra are indicative of large turbulent motions. From the millimeter wave CO observations, a total mass of molecular gas of 4 x 10 to the 10th solar masses is inferred. The OH emission in the 1667 MHz line is the most luminous extragalactic OH maser reported so far, with an isotropic luminosity of 1800 solar luminosities.

  4. Detection of H I, OH, CO, and optical imaging of the distant galaxy IRAS 12112 + 0305

    NASA Technical Reports Server (NTRS)

    Mirabel, I. F.; Kazes, I.; Sanders, D. B.

    1988-01-01

    The detection of H I absorption and OH and CO emission from the galaxy IRAS 12112 + 0305, which is receding from the sun at about 7 percent of the speed of light is reported. This galaxy, which appears to be an ongoing merger, radiates about 2 x 10 to the 12th solar luminosities in the infrared. The H I, OH, and CO spectra are indicative of large turbulent motions. From the millimeter wave CO observations, a total mass of molecular gas of 4 x 10 to the 10th solar masses is inferred. The OH emission in the 1667 MHz line is the most luminous extragalactic OH maser reported so far, with an isotropic luminosity of 1800 solar luminosities.

  5. 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.

  6. Multiple jets from the young star IRAS 21334 + 5039

    NASA Technical Reports Server (NTRS)

    Smith, Howard A.; Fischer, Jacqueline

    1992-01-01

    The source IRAS 21334 + 5039, a young stellar object (YSO) with broad CO outflow velocity profiles, was imaged in the 1-2 micron region with broad-band J, H, and K filters, and with a Fabry-Perot set to the molecular hydorgen v = 1-0 S(1) line, the hydrogen Br-gamma recombination line, and the neighboring continua. At 2 microns the source has an elongated continuum emission structure centered on the star. The structure has very blue tips, with a weak VLA 6 cm continuum source coincident with one of them. Strong molecular hydrogen emission appears as bow-shaped arcs oriented along an axis perpendicular to the continuum emission, and as a weaker structure aligned with it. Both the continuum and the molecular hydrogen emission are most likely produced by jets, possibly emanating in multiple directions from the central source at large angles to each other. While jets are a common feature of young stars, this source provides solid evidence for multiple jet structures.

  7. VizieR Online Data Catalog: Class 0 sources continuum subtracted UV-tables (Persson+, 2016)

    NASA Astrophysics Data System (ADS)

    Persson, M. V.; Harsono, D.; Tobin, J. J.; van Dishoeck, E. F.; Joergensen, J. K.; Murillo, N.; Lai, S.-P.

    2016-03-01

    This dataset contains the continuum subtracted UV-tables, in UVFITS format written by GILDAS MAPPING for the sources NGC 1333 IRAS 2A (203GHz), NGC 1333 IRAS 4A (335GHz), NGC 1333 IRAS 4B (203GHz), and VLA 1623 (219GHz). (2 data files).

  8. 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.

  9. 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.

  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.

  11. 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.

  12. 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.

  13. Teaching with IRA in the Mwanza Region of Tanzania

    ERIC Educational Resources Information Center

    McDermott, Peter

    2010-01-01

    This is a descriptive self-study of my experience participating in IRA's Diagnostic Teaching Project in Tanzania. The paper describes the teacher educators with whom I worked, their responses to IRA's curriculum, and what I learned about Tanzanian people, culture and education. Data are derived from a Likert survey, an open-item questionnaire, and…

  14. Commentary: An Exchange of Views on IRA and Reading Methods.

    ERIC Educational Resources Information Center

    Groff, Patrick; And Others

    1980-01-01

    Groff argues against an IRA (International Reading Association) position statement assertion that no single method is the best for teaching reading, claiming that the phonics method results in the greatest reading achievement. The IRA Board of Directors replies that the position statement appropriately reflects the diverse views about reading held…

  15. 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.

  16. IRAS low-resolution spectra of galaxies

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Volk, Kevin

    1989-01-01

    The spectra of external galaxies are selected and extracted from the IRAS LRS database. Twenty-one objects present viable spectra. One is a peculiar star-forming E-S0 galaxy. The remainder are all starburst or H II region galaxies. Their average spectrum demonstrates the importance of the PAH emission bands in the 8-23-micron region and reinforces the conclusion reached from ground-based spectra, that there is a strong correlation between the PAH bands and the starburst or H II region character of a galaxy.

  17. Wavelet analysis applied to the IRAS cirrus

    NASA Technical Reports Server (NTRS)

    Langer, William D.; Wilson, Robert W.; Anderson, Charles H.

    1994-01-01

    The structure of infrared cirrus clouds is analyzed with Laplacian pyramid transforms, a form of non-orthogonal wavelets. Pyramid and wavelet transforms provide a means to decompose images into their spatial frequency components such that all spatial scales are treated in an equivalent manner. The multiscale transform analysis is applied to IRAS 100 micrometer maps of cirrus emission in the north Galactic pole region to extract features on different scales. In the maps we identify filaments, fragments and clumps by separating all connected regions. These structures are analyzed with respect to their Hausdorff dimension for evidence of the scaling relationships in the cirrus clouds.

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

    SciTech Connect

    Lonsdale, C.J.; Hacking, P.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. 81 refs.

  19. Spectroscopy of IRAS 02091+6333

    NASA Astrophysics Data System (ADS)

    Bacher, Arntraud; Emprechtinger, Martin; Grömer, Gernot E.; Kapferer, Wolfgang; Kausch, Wolfgang; Kimeswenger, Stefan; Kitzbichler, Manfred G.; Lechner, Michaela F. M.; Lederle, Cornelia

    2003-07-01

    We present a detailed spectroscopic investigation, spanning four winters, of the asymptotic giant branch star IRAS 02091+6333. Zijlstra & Weinberger (2002) found a giant wall of dust around this star and modelled this unique phenomenon. However their work suffered from the quality of the optical investigations of the central object. They could use only a single quick look spectrum and the original TYCHO Bt and Vt magnitudes to estimate the spectral type and the interstellar extinction towards the target. Thus we obtained spectra and photometry at the Innsbruck 60cm telescope (Kimeswenger 2001) of this unique object for several years to derive an accurate spectral type and the foreground extinction. This allowed us to determine more precisely the distance to the target which is important for the modelling of the dust shell found on IRAS images. Zijlstra & Weinberger (2002) outline such shells for various types of objects at late stages of their evolution. Their focus was especially on a swept up shell with a void in the interstellar matter around the target. This is crucial for both, the "Swiss cheese" like structure of the interstellar material and for the hydrodynamic evolution of the planetary nebula built after the current evolutionary stage. The measurements presented here suggest a weak irregular photometric variability of the target, while there is no evidence of a spectroscopic variability over the last four years.

  20. LED light engine concept with ultra-high scalable luminance

    NASA Astrophysics Data System (ADS)

    Hoelen, Christoph; de Boer, Dick; Bruls, Dominique; van der Eyden, Joost; Koole, Rolf; Li, Yun; Mirsadeghi, Mo; Vanbroekhoven, Vincent; Van den Bergh, John-John; Van de Voorde, Patrick

    2016-03-01

    Although LEDs have been introduced successfully in many general lighting applications during the past decade, high brightness light source applications are still suffering from the limited luminance of LEDs. High power LEDs are generally limited in luminance to ca 100 Mnit (108 lm/m2sr) or less, while dedicated devices for projection may achieve luminance values up to ca 300 Mnit with phosphor converted green. In particular for high luminous flux applications with limited étendue, like in front projection systems, only very modest luminous flux values in the beam can be achieved with LEDs compared to systems based on discharge lamps. In this paper we introduce a light engine concept based on a light converter rod pumped with blue LEDs that breaks through the étendue and brightness limits of LEDs, enabling LED light source luminance values that are more than 4 times higher than what can be achieved with LEDs so far. In LED front projection systems, green LEDs are the main limiting factor. With our green light emitting modules, peak luminance values well above 1.2 Gnit have been achieved, enabling doubling of the screen brightness of LED based DLP projection systems, and even more when this technology is applied to other colors as well. This light source concept, introduced as the ColorSpark High Lumen Density (HLD) LED technology, enables a breakthrough in the performance of LED-based light engines not only for projection, where >2700 ANSI lm was demonstrated, but for a wide variety of high brightness applications.

  1. Photometric monitoring of Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Buemi, Carla; Distefano, Elisa; Leto, Paolo; Schillirò, Francesco; Trigilio, Corrado; Umana, Grazia; Bernabei, Stefano; Cutispoto, Giuseppe; Messina, Sergio

    2011-01-01

    We present some preliminary results from our program of intensive near-infrared photometric monitoring of a sample of confirmed and candidate Luminous Blue Variables (LBVs) conducted from 2008 to 2010. Clear long-term variability has been observed for Wray 17-96 and V481 Sct, with overall brightness variation greater than 1 mag in the J band. Other sources, such as LBV 1806-20 showed detectable variability with amplitudes of few tenths of a magnitude with a time-scale of about 60 days.

  2. Luminous Extragalactic Transients

    NASA Astrophysics Data System (ADS)

    O'Brien, Paul; Jonker, Peter; Athena Explosive Transients Working Group

    2015-09-01

    The ESA Athena X-ray observatory mission will combine exceptionally high throughout with high spectral-energy resolution and will revolutionise many aspects of high-energy astrophysics. Many of the most powerful transient sources, including gamma-ray bursts and tidal disruptions events, are bright X-ray sources. Athena will be designed to have a fast-response capability permitting efficient observations of many transients. We will summarise the proposed capability of the mission and illustrate science programs to study transients ranging from the most distant GRBs to nuclear activity in nearby galaxies.

  3. 26 CFR 1.408A-4 - Converting amounts to Roth IRAs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Converting amounts to Roth IRAs. 1.408A-4... amounts to Roth IRAs. This section sets forth the following questions and answers that provide rules applicable to Roth IRA conversions: Q-1. Can an individual convert an amount in his or her traditional IRA...

  4. 26 CFR 1.408(q)-1 - Deemed IRAs in qualified employer plans.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... account or annuity meets the requirements applicable to Roth IRAs under section 408A, the account or annuity is deemed to be a Roth IRA. Simplified employee pensions (SEPs) under section 408(k) and SIMPLE... distributions from traditional and Roth IRAs may be imposed on distributions from deemed IRAs (for...

  5. 26 CFR 1.408(q)-1 - Deemed IRAs in qualified employer plans.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... account or annuity meets the requirements applicable to Roth IRAs under section 408A, the account or annuity is deemed to be a Roth IRA. Simplified employee pensions (SEPs) under section 408(k) and SIMPLE... distributions from traditional and Roth IRAs may be imposed on distributions from deemed IRAs (for...

  6. 26 CFR 1.408(q)-1 - Deemed IRAs in qualified employer plans.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... account or annuity meets the requirements applicable to Roth IRAs under section 408A, the account or annuity is deemed to be a Roth IRA. Simplified employee pensions (SEPs) under section 408(k) and SIMPLE... distributions from traditional and Roth IRAs may be imposed on distributions from deemed IRAs (for...

  7. Spectropolarimetry of hot, luminous stars

    NASA Technical Reports Server (NTRS)

    Schulte-Ladbeck, Regina E.

    1994-01-01

    I review polarimetric observations of presumably single, hot luminous stars. The stellar types discussed are OB stars. B(e) supergiants, Luminous Blue Variables (LBV), Wolf-Rayet (W-R) stars, and type II supernovae (SN). It is shown that variable, intrinsic polarization is a common phenomenon in that part of the Hertzsprung-Russell (HR) diagram which these stars occupy. However, much observational work remains to be done before we can answer the most basic, statistical questions about the polarimetric properties of different groups of hot, luminous stars. Insight into the diagnostic power of polarization observations has been gained, but cannot be exploited without detailed models. Thus, while polarimetric observations do tell us that the mass-loss processes of all types of massive stars are time-dependent and anisotropic, the significance that this might have for the accuracy of their stellar parameters and evolutionary paths remains elusive.

  8. Anatomy of the internal bow shocks in the IRAS 04166+2706 protostellar jet

    NASA Astrophysics Data System (ADS)

    Tafalla, M.; Su, Y.-N.; Shang, H.; Johnstone, D.; Zhang, Q.; Santiago-García, J.; Lee, C.-F.; Hirano, N.; Wang, L.-Y.

    2017-01-01

    Context. Highly collimated jets and wide-angle outflows are two related components of the mass-ejection activity associated with stellar birth. Despite decades of research, the relation between these two components remains poorly understood. Aims: We study the relation between the jet and the outflow in the IRAS 04166+2706 protostar. This Taurus protostar drives a molecular jet that contains multiple emission peaks symmetrically located from the central source. The protostar also drives a wide-angle outflow consisting of two conical shells. Methods: We have used the Atacama Large Millimeter/submillimeter Array (ALMA) interferometer to observe two fields along the IRAS 04166+2706 jet. The fields were centered on a pair of emission peaks that correspond to the same ejection event. The observations were carried out in CO(2-1), SiO(5-4), and SO(JN = 65-54). Results: Both ALMA fields present spatial distributions that are approximately elliptical and have their minor axes aligned with the jet direction. As the velocity increases, the emission in each field moves gradually across the elliptical region. This systematic pattern indicates that the emitting gas in each field lies in a disk-like structure that is perpendicular to the jet axis and whose gas is expanding away from the jet. A small degree of curvature in the first-moment maps indicates that the disks are slightly curved in the manner expected for bow shocks moving away from the IRAS source. A simple geometrical model confirms that this scenario fits the main emission features. Conclusions: The emission peaks in the IRAS 04166+2706 jet likely represent internal bow shocks where material is being ejected laterally away from the jet axis. While the linear momentum of the ejected gas is dominated by the component in the jet direction, the sideways component is not negligible, and can potentially affect the distribution of gas in the surrounding outflow and core.

  9. Trigonometric distance and proper motion of IRAS 20056+3350: a massive star-forming region on the solar circle

    SciTech Connect

    Burns, Ross A.; Handa, Toshihiro; Omodaka, Toshihiro; Nakagawa, Akiharu; Nakanishi, Hiroyuki; Nagayama, Takumi; Hayashi, Masahiko; Shizugami, Makoto

    2014-12-10

    We report our measurement of the trigonometric distance and proper motion of IRAS 20056+3350, obtained from the annual parallax of H{sub 2}O masers. Our distance of D=4.69{sub −0.51}{sup +0.65} kpc, which is 2.8 times larger than the near kinematic distance adopted in the literature, places IRAS 20056+3350 at the leading tip of the Local arm and proximal to the solar circle. Using our distance, we reevaluate past observations to reveal IRAS 20056+3350 as a site of massive star formation at a young stage of evolution. This result is consistent with the spectral energy distribution of the source evaluated with published photometric data from UKIDSS, WISE, AKARI, IRAS, and the submillimeter continuum. Both analytical approaches reveal the luminosity of the region to be 2.4 × 10{sup 4} L {sub ☉}, and suggest that IRAS 20056+3350 is forming an embedded star of ≥16 M {sub ☉}. We estimated the proper motion of IRAS 20056+3350 to be (μ{sub α}cos δ, μ{sub δ}) = (–2.62 ± 0.33, –5.65 ± 0.52) mas yr{sup –1} from the group motion of H{sub 2}O masers, and use our results to estimate the angular velocity of Galactic rotation at the Galactocentric distance of the Sun, Ω{sub 0} = 29.75 ± 2.29 km s{sup –1} kpc{sup –1}, which is consistent with the values obtained for other tangent point and solar circle objects.

  10. 26 CFR 1.408A-1 - Roth IRAs in general.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Roth IRAs in general. 1.408A-1 Section 1.408A-1...) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-1 Roth IRAs in general... features of Roth IRAs: Q-1. What is a Roth IRA? A-1. (a) A Roth IRA is a new type of individual...

  11. 26 CFR 1.408A-1 - Roth IRAs in general.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Roth IRAs in general. 1.408A-1 Section 1.408A-1...) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-1 Roth IRAs in general... features of Roth IRAs: Q-1. What is a Roth IRA? A-1. (a) A Roth IRA is a new type of individual...

  12. 26 CFR 1.408A-1 - Roth IRAs in general.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Roth IRAs in general. 1.408A-1 Section 1.408A-1...) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-1 Roth IRAs in general... features of Roth IRAs: Q-1. What is a Roth IRA? A-1. (a) A Roth IRA is a new type of individual...

  13. 26 CFR 1.408A-1 - Roth IRAs in general.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Roth IRAs in general. 1.408A-1 Section 1.408A-1...) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-1 Roth IRAs in general... features of Roth IRAs: Q-1. What is a Roth IRA? A-1. (a) A Roth IRA is a new type of individual...

  14. OT1_dweedman_1: Comparing [CII] 158 micron Luminosities to Spectral Properties of Luminous Starburst Galaxies and AGN

    NASA Astrophysics Data System (ADS)

    Weedman, D.

    2010-07-01

    Herschel PACS spectroscopy of the [CII] emission line at 158 microns is proposed for a carefully selected sample of 123 sources that already have complete low and high resolution mid-infrared spectra between 5 microns and 35 microns from the Spitzer Infrared Spectrograph, and which also have spectral energy distributions (SEDs) from IRAS and Akari photometry. [CII] 158 um is the strongest far-infrared emission line and therefore crucial to compare with other features in luminous, dusty galaxies. Sources have 0.004 < z < 0.34 and 43.0 < log L(IR) < 46.8 (erg per sec) and cover the full range of starburst galaxy and AGN classifications. Obtaining these [CII] line fluxes with PACS will allow: 1. determining how precisely [CII] luminosity measures star formation rate by comparing to PAH features and emission lines that arise in starburst galaxies; 2. determining how [CII] luminosity and equivalent width changes with starburst/AGN fraction, by comparing with strength and equivalent width of PAH and [NeII] emission arising from starbursts, and with strength of high ionization lines [NeV] and [OIV] and silicate absorption or emission arising from AGN; 3. determining how [CII] luminosity and equivalent width changes with dust temperature and bolometric luminosity, as derived from spectral energy distributions, and whether this depends on the starburst/AGN fraction. These determinations will allow interpretation of high redshift sources for which the only available diagnostics are the luminosity and equivalent width of the [CII] line and the far-infrared rest-frame SED. The total observing program requires 20.2 hours of Herschel observing time.

  15. IRAS Observations of Delta Scuti Stars

    NASA Astrophysics Data System (ADS)

    Templeton, M. R.; Harrison, T. E.

    1998-07-01

    Mid-far infrared and radio observations of A-F stars are important for constraining the level of mass loss from these stars. It was theorized by Willson et al. (1987) that mass loss could play a significant role in the evolution of these stars, and could be responsible for shifting a star in the HR diagram by as much as one spectral class. Observations of normal A-F stars at 6 cm by Brown et al. (1990) and at the IRAS 12, 25, and 60 5m bands by Patten and Willson (1991) have shown that extreme mass loss rates (on the order of 10^-8 to 10^-9 solar masses per year) are not seen in these stars, but lower mass loss rates could still have significant impact on the evolution of these stars [see Guzik and Cox (1995) for example].

  16. The IRAS project organisation and mission operations

    NASA Technical Reports Server (NTRS)

    Van Holtz, R. C.

    1983-01-01

    The project organisation of IRAS is described, showing the tasks assigned to each project group during post-launch operations. The satellite is described, emphasizing the detectors. In the task division, the role of the U.S. is to construct the telescope and survey instrument, launch the satellite, process final science data for the survey instrument, and provide certain standard satellite items. The Netherlands construct the spacecraft and three additional instruments, integrates and tests the overall satellite, and designs and participates in the development of the operational system. The U.K. provides the operational control center and primary tracking station, generates a system for preliminary science analysis of the survey data, provides housekeeping analysis software and science data distribution software, and staffs the control center operations. The teams involved in mission planning and operations, and their roles, are identified, and a block diagram of the operations organisation is presented.

  17. Ira Remsen, saccharin, and the linear model.

    PubMed

    Warner, Deborah J

    2008-03-01

    While working in the chemistry laboratory at Johns Hopkins University, Constantin Fahlberg oxidized the 'ortho-sulfamide of benzoic acid' and, by chance, found the result to be incredibly sweet. Several years later, now working on his own, he termed this stuff saccharin, developed methods of making it in quantity, obtained patents on these methods, and went into production. As the industrial and scientific value of saccharin became apparent, Ira Remsen pointed out that the initial work had been done in his laboratory and at his suggestion. The ensuing argument, carried out in the courts of law and public opinion, illustrates the importance of the linear model to scientists who staked their identities on the model of disinterested research but who also craved credit for important practical results.

  18. ALMA 690 GHz OBSERVATIONS OF IRAS 16293-2422B: INFALL IN A HIGHLY OPTICALLY THICK DISK

    SciTech Connect

    Zapata, Luis A.; Loinard, Laurent; Rodriguez, Luis F.; Hernandez-Hernandez, Vicente; Takahashi, Satoko; Trejo, Alfonso; Parise, Berengere

    2013-02-10

    We present sensitive, high angular resolution ({approx}0.''2) submillimeter continuum and line observations of IRAS 16293-2422B made with the Atacama Large Millimeter/Submillimeter Array. The 0.45 mm continuum observations reveal a single and very compact source associated with IRAS 16293-2422B. This submillimeter source has a deconvolved angular size of about 400 mas (50 AU) and does not show any inner structure inside of this diameter. The H{sup 13}CN, HC{sup 15}N, and CH{sub 3}OH line emission regions are about twice as large as the continuum emission and reveal a pronounced inner depression or ''hole'' with a size comparable to that estimated for the submillimeter continuum. We suggest that the presence of this inner depression and the fact that we do not see an inner structure (or a flat structure) in the continuum are produced by very optically thick dust located in the innermost parts of IRAS 16293-2422B. All three lines also show pronounced inverse P-Cygni profiles with infall and dispersion velocities larger than those recently reported from observations at lower frequencies, suggesting that we are detecting faster and more turbulent gas located closer to the central object. Finally, we report a small east-west velocity gradient in IRAS 16293-2422B that suggests that its disk plane is likely located very close to the plane of the sky.

  19. ALMA 690 GHz Observations of IRAS 16293-2422B: Infall in a Highly Optically Thick Disk

    NASA Astrophysics Data System (ADS)

    Zapata, Luis A.; Loinard, Laurent; Rodríguez, Luis F.; Hernández-Hernández, Vicente; Takahashi, Satoko; Trejo, Alfonso; Parise, Bérengère

    2013-02-01

    We present sensitive, high angular resolution (~0.''2) submillimeter continuum and line observations of IRAS 16293-2422B made with the Atacama Large Millimeter/Submillimeter Array. The 0.45 mm continuum observations reveal a single and very compact source associated with IRAS 16293-2422B. This submillimeter source has a deconvolved angular size of about 400 mas (50 AU) and does not show any inner structure inside of this diameter. The H13CN, HC15N, and CH3OH line emission regions are about twice as large as the continuum emission and reveal a pronounced inner depression or "hole" with a size comparable to that estimated for the submillimeter continuum. We suggest that the presence of this inner depression and the fact that we do not see an inner structure (or a flat structure) in the continuum are produced by very optically thick dust located in the innermost parts of IRAS 16293-2422B. All three lines also show pronounced inverse P-Cygni profiles with infall and dispersion velocities larger than those recently reported from observations at lower frequencies, suggesting that we are detecting faster and more turbulent gas located closer to the central object. Finally, we report a small east-west velocity gradient in IRAS 16293-2422B that suggests that its disk plane is likely located very close to the plane of the sky.

  20. IRAS galaxies at low galactic and high supergalactic latitudes

    SciTech Connect

    Dow, M.W.; Lu, N.Y.; Houck, J.R.; Salpeter, E.E.; Lewis, B.M.

    1988-01-01

    Based on IR colors, 371 IRAS point sources with absolute value of b = 2-16 deg (b = galactic latitude) were selected for study at H I 21 cm as potential galaxies: 25 percent (93) of these sources are galaxies with redshifts less than 8000 km/s based on H I spectra. Most of the detected galaxies are at redshifts between 2000 and 7500 km/s. Fifty-five of these lie in an area about 40 deg away from the junction of the Pisces-Perseus and Lynx-Ursa Major superclusters, and show a distribution of systemic velocities very similar to these superclusters. There is an enhanced density of galaxies near 6000 km/s with galactic longitude l about 40 deg and b about 0 deg. The two regions surveyed, centered at l about 192 deg and l about 54 deg, lie outside the plane of the Local Supercluster and do not show any preference for galaxies with low velocity widths. 16 references.

  1. IRAS galaxies at low galactic and high supergalactic latitudes

    NASA Technical Reports Server (NTRS)

    Dow, M. W.; Lu, N. Y.; Houck, J. R.; Salpeter, E. E.; Lewis, B. M.

    1988-01-01

    Based on IR colors, 371 IRAS point sources with absolute value of b = 2-16 deg (b = galactic latitude) were selected for study at H I 21 cm as potential galaxies: 25 percent (93) of these sources are galaxies with redshifts less than 8000 km/s based on H I spectra. Most of the detected galaxies are at redshifts between 2000 and 7500 km/s. Fifty-five of these lie in an area about 40 deg away from the junction of the Pisces-Perseus and Lynx-Ursa Major superclusters, and show a distribution of systemic velocities very similar to these superclusters. There is an enhanced density of galaxies near 6000 km/s with galactic longitude l about 40 deg and b about 0 deg. The two regions surveyed, centered at l about 192 deg and l about 54 deg, lie outside the plane of the Local Supercluster and do not show any preference for galaxies with low velocity widths.

  2. Spectrum from Faint Galaxy IRAS F00183-7111

    NASA Technical Reports Server (NTRS)

    2003-01-01

    NASA's Spitzer Space Telescope has detected the building blocks of life in the distant universe, albeit in a violent milieu. Training its powerful infrared eye on a faint object located at a distance of 3.2 billion light-years, Spitzer has observed the presence of water and organic molecules in the galaxy IRAS F00183-7111. With an active galactic nucleus, this is one of the most luminous galaxies in the universe, rivaling the energy output of a quasar. Because it is heavily obscured by dust (see visible-light image in the inset), most of its luminosity is radiated at infrared wavelengths.

    The infrared spectrograph instrument onboard Spitzer breaks light into its constituent colors, much as a prism does for visible light. The image shows a low-resolution spectrum of the galaxy obtained by the spectrograph at wavelengths between 4 and 20 microns. Spectra are graphical representations of a celestial object's unique blend of light. Characteristic patterns, or fingerprints, within the spectra allow astronomers to identify the object's chemical composition and to determine such physical properties as temperature and density.

    The broad depression in the center of the spectrum denotes the presence of silicates (chemically similar to beach sand) in the galaxy. An emission peak within the bottom of the trough is the chemical signature for molecular hydrogen. The hydrocarbons (orange) are organic molecules comprised of carbon and hydrogen, two of the most common elements on Earth. Since it has taken more than three billion years for the light from the galaxy to reach Earth, it is intriguing to note the presence of organics in a distant galaxy at a time when life is thought to have started forming on our home planet.

    Additional features in the spectrum reveal the presence of water ice (blue), carbon dioxide ice (green) and carbon monoxide (purple) in both gas and solid forms. The magenta peak corresponds to singly ionized neon gas, a spectral line often used by

  3. Reprocessing in Luminous Disks

    NASA Technical Reports Server (NTRS)

    Bell, K. Robbins; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    We develop and investigate a procedure that accounts for disk reprocessing of photons that originate in the disk itself. Surface temperatures and simple, black body spectral energy distributions (SEDs) of protostellar disks are calculated. In disks that flare with radius, reprocessing of stellar photons results in temperature profiles considerably shallower than r(sup -3/4). Including the disk as a radiation source (as in the case of actively secreting disks) along with the stellar source further flattens the temperature profile. Disks that flare strongly near the star and then smoothly curve over and become shadowed at some distance ("decreasing curvature" disks) exhibit nearly power-law temperature profiles which result in power-law infrared SEDs with slopes in agreement with typical observations of young stellar objects. Disk models in which the photospheric thickness is controlled by the local opacity and in which the temperature decreases with radius naturally show this shape. Uniformly flaring models do not match observations as well; progressively stronger reprocessing at larger radii leads to SEDs that flatten toward the infrared or even have a second peak at the wavelength corresponding (through the Wien law) to the temperature of the outer edge of the disk. In FU Orionis outbursting systems, the dominant source of energy is the disk itself. The details of the reprocessing depend sensitively on the assumed disk shape and emitted temperature profile. The thermal instability outburst models of Bell Lin reproduce trends in the observed SEDs of Fuors with T varies as r(sup -3/4) in the inner disk (r approx. less than 0.25au corresponding to lambda approx. less than 10 microns) and T varies as r(sup -1/2) in the outer disk. Surface irradiation during outburst and quiescence is compared in the region of planet formation (1 - 10 au). The contrast between the two phases is diminished by the importance of the reprocessing of photons from the relatively high mass

  4. Reprocessing in Luminous Disks

    NASA Technical Reports Server (NTRS)

    Bell, K. Robbins; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    We develop and investigate a procedure that accounts for disk reprocessing of photons that originate in the disk itself. Surface temperatures and simple, black body spectral energy distributions (SEDs) of protostellar disks are calculated. In disks that flare with radius, reprocessing of stellar photons results in temperature profiles considerably shallower than r(sup -3/4). Including the disk as a radiation source (as in the case of actively secreting disks) along with the stellar source further flattens the temperature profile. Disks that flare strongly near the star and then smoothly curve over and become shadowed at some distance ("decreasing curvature" disks) exhibit nearly power-law temperature profiles which result in power-law infrared SEDs with slopes in agreement with typical observations of young stellar objects. Disk models in which the photospheric thickness is controlled by the local opacity and in which the temperature decreases with radius naturally show this shape. Uniformly flaring models do not match observations as well; progressively stronger reprocessing at larger radii leads to SEDs that flatten toward the infrared or even have a second peak at the wavelength corresponding (through the Wien law) to the temperature of the outer edge of the disk. In FU Orionis outbursting systems, the dominant source of energy is the disk itself. The details of the reprocessing depend sensitively on the assumed disk shape and emitted temperature profile. The thermal instability outburst models of Bell Lin reproduce trends in the observed SEDs of Fuors with T varies as r(sup -3/4) in the inner disk (r approx. less than 0.25au corresponding to lambda approx. less than 10 microns) and T varies as r(sup -1/2) in the outer disk. Surface irradiation during outburst and quiescence is compared in the region of planet formation (1 - 10 au). The contrast between the two phases is diminished by the importance of the reprocessing of photons from the relatively high mass

  5. IRAS 18113-2503: THE WATER FOUNTAIN WITH THE FASTEST JET?

    SciTech Connect

    Gomez, Jose F.; Guerrero, MartIn A.; Ricardo Rizzo, J.; Suarez, Olga; Miranda, Luis F.

    2011-09-20

    We present Expanded Very Large Array water maser observations at 22 GHz toward the source IRAS 18113-2503. Maser components span over a very high velocity range of {approx_equal} 500 km s{sup -1}, the second largest found in a Galactic maser, only surpassed by the high-mass star-forming region W49N. Maser components are grouped into a blueshifted and a redshifted cluster, separated by 0.''12. Further mid-IR and radio data suggest that IRAS 18113-2503 is a post-asymptotic giant branch star, thus a new bona fide member of the rare class of 'water fountains' (WFs). It is the evolved object with the largest total velocity spread in its water masers and with the highest velocity dispersion within its redshifted and blueshifted lobes ({approx_equal} 170 km s{sup -1}). The large total velocity range of emission probably indicates that IRAS 18113-2503 has the fastest jet among the known WF stars. On the other hand, the remarkably high velocity dispersion within each lobe may be interpreted in terms of shocks produced by an episode of mass ejection whose velocity increased up to very high values or, alternatively, by projection effects in a jet with a large opening angle and/or precessing motions.

  6. DISTRIBUTION OF CH{sub 3}OH IN NGC 1333 IRAS4B

    SciTech Connect

    Sakai, Nami; Yamamoto, Satoshi; Ceccarelli, Cecilia; Bottinelli, Sandrine; Sakai, Takeshi

    2012-07-20

    Distribution of the CH{sub 3}OH (J{sub K} = 2{sub K}-1{sub K}, 96.7 GHz) emission has been investigated toward NGC 1333 IRAS4B, a low-mass Class 0 protostar which harbors a hot corino, with Nobeyama Millimeter Array. The CH{sub 3}OH emission is found to be prominent in the shocked region caused by an impact of the molecular outflow from the protostars. The direction of the outflow which is responsible for the shock seems to be opposite to that of a compact outflow known previously in the CO (J = 2-1), HCN (J = 1-0), H{sub 2}CO (3{sub 12}-2{sub 11}), and CH{sub 3}OH (J{sub K} = 7{sub K}-6{sub K}) emissions, whereas it is the same as that of the faint second outflow found in the H{sub 2}CO emission. This double outflow structure can be interpreted most naturally by the existence of more than two protostars in IRAS4B. On the other hand, a centrally condensed component associated apparently with IRAS4B cannot be recognized in our CH{sub 3}OH observation. Our observation suggests that, in this source, the CH{sub 3}OH (J{sub K} 2{sub K}-1{sub K}) emission preferentially traces the shocked regions rather than the hot corino around the protostar.

  7. A very deep IRAS survey at l(II) = 97 deg, b(II) = +30 deg

    NASA Astrophysics Data System (ADS)

    Hacking, Perry; Houck, James R.

    1987-05-01

    A deep far-infrared survey is presented using over 1000 scans made of a 4 to 6 sq. deg. field at the north ecliptic pole by the IRAS. Point sources from this survey are up to 100 times fainter than the IRAS point source catalog at 12 and 25 micrometers, and up to 10 times fainter at 60 and 100 micrometers. The 12 and 25 micrometer maps are instrumental noise-limited, and the 60 and 100 micrometer maps are confusion noise-limited. The majority of the 12 micrometer point sources are stars within the Milky Way. The 25 micrometer sources are composed almost equally of stars and galaxies. About 80% of the 60 micrometer sources correspond to galaxies on Palomar Observatory Sky Survey (POSS) enlargements. The remaining 20% are probably galaxies below the POSS detection limit. The differential source counts are presented and compared with what is predicted by the Bahcall and Soneira Standard Galaxy Model using the B-V-12 micrometer colors of stars without circumstellar dust shells given by Waters, Cote and Aumann. The 60 micrometer source counts are inconsistent with those predicted for a uniformly distributed, nonevolving universe. The implications are briefly discussed.

  8. A very deep IRAS survey at l(II) = 97 deg, b(II) = +30 deg

    NASA Technical Reports Server (NTRS)

    Hacking, Perry; Houck, James R.

    1987-01-01

    A deep far-infrared survey is presented using over 1000 scans made of a 4 to 6 sq. deg. field at the north ecliptic pole by the IRAS. Point sources from this survey are up to 100 times fainter than the IRAS point source catalog at 12 and 25 micrometers, and up to 10 times fainter at 60 and 100 micrometers. The 12 and 25 micrometer maps are instrumental noise-limited, and the 60 and 100 micrometer maps are confusion noise-limited. The majority of the 12 micrometer point sources are stars within the Milky Way. The 25 micrometer sources are composed almost equally of stars and galaxies. About 80% of the 60 micrometer sources correspond to galaxies on Palomar Observatory Sky Survey (POSS) enlargements. The remaining 20% are probably galaxies below the POSS detection limit. The differential source counts are presented and compared with what is predicted by the Bahcall and Soneira Standard Galaxy Model using the B-V-12 micrometer colors of stars without circumstellar dust shells given by Waters, Cote and Aumann. The 60 micrometer source counts are inconsistent with those predicted for a uniformly distributed, nonevolving universe. The implications are briefly discussed.

  9. Application of MCM image construction to IRAS comet observations

    NASA Technical Reports Server (NTRS)

    Schlapfer, Martin F.; Walker, Russell G.

    1994-01-01

    There is a wealth of IRAS comet data, obtained in both the survey and pointed observations modes. However, these measurements have remained largely untouched due to difficulties in removing instrumental effects from the data. We have developed a version of the Maximum Correlation Method for Image Construction algorithm (MCM) which operates in the moving coordinate system of the comet and properly treats both real cometary motion and apparent motion due to spacecraft parallax. This algorithm has been implemented on a 486/33 PC in FORTRAN and IDL codes. Preprocessing of the IRAS CRDD includes baseline removal, deglitching, and removal of long tails due to dielectric time constants of the detectors. The resulting images are virtually free from instrumental effects and have the highest possible spatial resolution consistent with the data sampling. We present examples of high resolution IRAS images constructed from survey observations of Comets P/Tempel 1 and P/Tempel 2, and pointed observations of IRAS-Araki-Alcock.

  10. 26 CFR 1.408A-2 - Establishing Roth IRAs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) INCOME TAXES Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-2 Establishing Roth IRAs... established with any bank, insurance company, or other person authorized in accordance with § 1.408-2(e) to...

  11. IRAS 20050+2720: Anatomy of a Young Stellar Cluster

    NASA Astrophysics Data System (ADS)

    Günther, H. M.; Wolk, S. J.; Spitzbart, B.; Gutermuth, R. A.; Forbrich, J.; Wright, N. J.; Allen, L.; Bourke, T. L.; Megeath, S. T.; Pipher, J. L.

    2012-10-01

    IRAS 20050+2720 is young star-forming region at a distance of 700 pc without apparent high-mass stars. We present results of our multi-wavelength study of IRAS 20050+2720 which includes observations by Chandra and Spitzer, and Two Micron All Sky Survey and UBVRI photometry. In total, about 300 young stellar objects (YSOs) in different evolutionary stages are found. We characterize the distribution of YSOs in this region using a minimum spanning tree analysis. We newly identify a second cluster core, which consists mostly of class II objects, about 10' from the center of the cloud. YSOs of earlier evolutionary stages are more clustered than more evolved objects. The X-ray luminosity function (XLF) of IRAS 20050+2720 is roughly lognormal, but steeper than the XLF of the more massive Orion Nebula complex. IRAS 20050+2720 shows a lower N H/AK ratio compared with the diffuse interstellar medium.

  12. The C-terminal domains of human neurofibromin and its budding yeast homologs Ira1 and Ira2 regulate the metaphase to anaphase transition.

    PubMed

    Luo, Guangming; Kim, Junwon; Song, Kiwon

    2014-01-01

    The human tumor suppressor neurofibromin contains a cysteine and serine-rich domain/Ras-GTPase activating protein domain (CSRD/RasGAP) and a C-terminal domain (CTD). Domain studies of neurofibromin suggest it has other functions in addition to being a RasGAP, but the mechanisms underlying its tumor suppressor activity are not well understood. The budding yeast Saccharomyces cerevisiae is a good model system for studying neurofibromin function because it possesses Ira1 and Ira2, which are homologous to human neurofibromin in both sequence and function. We found that overexpression of CTD or a neurofibromin CTD-homologous domain (CHD) of Ira1/2 in budding yeast delayed degradation of the securin protein Pds1, whereas overexpression of CSRD/RasGAP did not affect Pds1 degradation. We also found that when CTD or CHD was overexpressed, the number of cells in metaphase was higher than in the control. These results demonstrate that CTD and CHD function in the metaphase to anaphase transition. In addition, Δiraira2 cells bypassed mitotic arrest in response to spindle damage, indicating that Ira1 and Ira2 may be involved in the spindle assembly checkpoint (SAC). However, Δiraira2Δmad2 cells are more sensitive to spindle damage than Δmad2 or Δiraira2 cells are, suggesting that Ira1/2 and Mad2 function in different pathways. Overexpression of CTD but not CSRD/RasGAP partially rescued the hypersensitivity of Δiraira2Δmad2 cells to microtubule-destabilizing drugs, indicating a role for CTD in the SAC pathway. Taken together, independently of RasGAP activity, the C-terminal domains of neurofibromin, Ira1, and Ira2 regulate the metaphase to anaphase transition in a Mad2-independent fashion.

  13. 78 FR 69710 - Luminant Generation Company, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-20

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Luminant Generation Company, LLC AGENCY: U.S. Nuclear Regulatory Commission (NRC). ACTION... consecutive weeks of a combined license (COL) application from Luminant Generation Company, LLC....

  14. 78 FR 66785 - Luminant Generation Company, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-06

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Luminant Generation Company, LLC AGENCY: Nuclear Regulatory Commission. ACTION: Notice of receipt... consecutive weeks of ] a combined license (COL) application from Luminant Generation Company, LLC....

  15. 78 FR 70964 - Luminant Generation Company, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-27

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Luminant Generation Company, LLC AGENCY: Nuclear Regulatory Commission. ACTION: Combined license... for four consecutive weeks of a combined license (COL) application from Luminant Generation...

  16. 78 FR 68100 - Luminant Generation Company, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-13

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Luminant Generation Company, LLC AGENCY: U.S. Nuclear Regulatory Commission (NRC). ACTION... consecutive weeks of a combined license (COL) application from Luminant Generation Company, LLC....

  17. Calibration of imaging luminance measuring devices (ILMD)

    NASA Astrophysics Data System (ADS)

    Liu, Liying; Zheng, Feng; Zhu, Lingxi; Li, Ye; Huan, Kewei; Shi, Xiaoguang

    2015-11-01

    A method of calibration of imaging luminance measuring devices has been studied. By the device-independent color space transformation, the color image by digital camera could be converted to the CIE's absolute color space lab. Then, the calibration model is fitted between ln(L/t) and luminance. At last, luminance image is obtained and the dynamic range of luminance image could be adjusted by shutter speed.

  18. Systematic analysis on the relationship between luminal enhancement, convolution kernel, plaque density, and luminal diameter of coronary artery stenosis: a CT phantom study.

    PubMed

    Morsbach, Fabian; Berger, Nicole; Desbiolles, Lotus; Poropat, Tadea; Leschka, Sebastian; Alkadhi, Hatem; Stolzmann, Paul

    2013-06-01

    To systematically investigate into the relationships between luminal enhancement, convolution kernel, plaque density, and stenosis severity in coronary computed tomography (CT) angiography. A coronary phantom including 63 stenoses (stenosis severity, 10-90%; plaque densities, -100 to 1,000 HU) was loaded with increasing solutions of contrast material (luminal enhancement, 0-700 HU) and scanned in an anthropomorphic chest. CT data was acquired with prospective triggering using 64-section dual-source CT; reconstructions were performed with soft-tissue (B26f) and sharp convolution kernels (B46f). Two blinded and independent readers quantitatively assessed luminal diameter and CT number of plaque using electronic calipers. Measurement bias between phantom dimensions and CT measurements were calculated. Multivariate linear regression models identified predictors of bias. Inter- and intra-reader agreements of luminal diameter and CT number measurements were excellent (ICCs > 0.91, p < 0.01, each). Measurement bias of luminal diameter and plaque density was significantly (p < 0.01, each) lower (-12% and 58 HU, respectively) with B46f as opposed to B26f, especially in plaque densities >200 HU. Measurement bias was significantly (p < 0.01, each) correlated (ρ = 0.37-55 and ρ = -0.70-85) with the differences between luminal enhancement and plaque density. In multivariate models, bias of luminal diameter assessment with CT was correlated with plaque density (β = 0.09, p < 0.05). Convolution kernel (β = -0.29 and -0.38), stenosis severity (β = -0.45 and -0.38), and luminal enhancement (β = -0.11 and -0.29) represented independent (p < 0.05,each) predictors of measurement bias of luminal diameter and plaque number, respectively. Significant independent relationships exist between luminal enhancement, convolution kernel, plaque density, and luminal diameter, which have to be taken into account when performing, evaluating, and interpreting coronary CT angiography.

  19. Dual-Pump CARS Thermometry in Highly Luminous Flames

    NASA Astrophysics Data System (ADS)

    Kearney, Sean

    2005-11-01

    Dual pump coherent anti-Stokes Raman scattering (CARS) investigations have been conducted in highly luminous flames. While the spatial coherence of the CARS signal permits efficient rejection of many optical background sources, spatially incoherent and spectrally broad interference from highly luminous flames can still be problematic. We have compared two approaches for time-resolved gating of the CARS signal beam against the luminous background from heavily sooting flames; (1) a fast liquid crystal shutter in conjunction with a standard unintensified CCD and (2) an interline-transfer CCD with reduced dynamic range. The fidelity of the dual-pump CARS facility for temperature measurements in these extremely hostile environments is evaluated and the relative merits of both detection approaches are discussed.

  20. Dust and gas environment of the young embedded cluster IRAS 18511+0146

    NASA Astrophysics Data System (ADS)

    Vig, S.; Testi, L.; Walmsley, C. M.; Cesaroni, R.; Molinari, S.

    2017-03-01

    Context. Since massive and intermediate mass stars form in clusters, a comparative investigation of the environments of the young embedded cluster members can reveal significant information about the conditions under which stars form and evolve. Aims: IRAS 18511+0146 is a young embedded (proto)cluster located at 3.5 kpc surrounding what appears to be an intermediate mass protostar. Here, we investigate the nature of cluster members (two of which are believed to be the most massive and luminous) using imaging and spectroscopy in the near and mid-infrared. In particular, we examine the three brightest mid-infrared objects, two of which are believed to be the most massive ones driving the luminosity of this region. Methods: Near-infrared spectroscopy of nine objects (bright in K-bands) towards IRAS 18511+0146 has been carried out. Several cluster members have also been investigated in the mid-infrared using spectroscopic and imaging with VISIR on the VLT. Far-infrared images from the Herschel Hi-GAL survey have been used to construct the column density and temperature maps of the region. Results: The brightest point-like object associated with IRAS 18511+0146 is referred to as S7 in the present work (designated UGPS J185337.88+015030.5 in the UKIRT Galactic Plane survey). S7 is likely the most luminous object in the cluster as it is bright at all wavelengths ranging from the near-infrared to millimetre. Seven of the nine objects show rising spectral energy distributions in the near-infrared, with four objects showing Br-γ emission. Three members: S7, S10 (also UGPS J185338.37+015015.3) and S11 (also UGPS J185338.72+015013.5) are bright in mid-infrared with diffuse emission being detected in the vicinity of S11 in PAH bands. Silicate absorption is detected towards these three objects, with an absorption maximum between 9.6 and 9.7 μm, large optical depths (1.8-3.2), and profile widths of 1.6-2.1μm. The silicate profiles of S7 and S10 are similar, in contrast to S11

  1. Chromospheres of Luminous Cool Stars

    NASA Astrophysics Data System (ADS)

    Dupree, Andrea K.; Avrett, Eugene

    2015-08-01

    Ultraviolet imaging of Alpha Orionis (Betelgeuse) reveals a complex variable chromospheric structure. Such atmospheres in luminous cool stars can affect features in the optical spectrum. Constructing semi-empiricalmodel atmospheres of luminous stars including the temperature rise due to a chromosphere allows us to predict potential effects on optical transitions. The radiative transfer code, PANDORA, calculates line strengths in a LTE or non-LTE formulation, spherical symmetry, and includes velocity fields when present. Various aspects of the line calculations and their impact on equivalent widths will be discussed including developing appropriate chromospheric models, comparison to a pure radiative equilibrium model, transitions sensitive to non-LTE and the effects of a realistic spherical non-LTE approximation as compared to a plane-parallel approximation. We discuss the extent to which a chromosphere can impact the determination of stellar abundances.

  2. Spectroscopic Variability of IRAS 22272+5435

    NASA Astrophysics Data System (ADS)

    Začs, Laimons; Musaev, Faig; Kaminsky, Bogdan; Pavlenko, Yakiv; Grankina, Aija; Sperauskas, Julius; Hrivnak, Bruce J.

    2016-01-01

    A time series of high-resolution spectra was observed in the optical wavelength region for the bright proto-planetary nebula IRAS 22272+5435 (HD 235858), along with a simultaneous monitoring of its radial velocity and BV RC magnitudes. The object is known to vary in light, color, and velocity owing to pulsation with a period of 132 days. The light and color variations are accompanied by significant changes in spectral features, most of which are identified as lines of carbon-bearing molecules. According to the observations, the C2 Swan system and CN Red system lines are stronger near the light minimum. A photospheric spectrum of the central star was calculated using new self-consistent atmospheric models. The observed intensity variations in the C2 Swan system and CN Red system lines were found to be much larger than expected if due solely to the temperature variation in the atmosphere of the pulsating star. In addition, the molecular lines are blueshifted relative to the photospheric velocity. The site of formation of the strong molecular features appears to be a cool outflow triggered by the pulsation. The variability in atomic lines seems to be mostly due variations of the effective temperature during the pulsation cycle. The profiles of strong atomic lines are split, and some of them are variable in a timescale of a week or so, probably because of shock waves in the outer atmosphere.

  3. SPECTROSCOPIC VARIABILITY OF IRAS 22272+5435

    SciTech Connect

    Začs, Laimons; Grankina, Aija; Musaev, Faig; Kaminsky, Bogdan; Pavlenko, Yakiv; Sperauskas, Julius; Hrivnak, Bruce J.

    2016-01-01

    A time series of high-resolution spectra was observed in the optical wavelength region for the bright proto-planetary nebula IRAS 22272+5435 (HD 235858), along with a simultaneous monitoring of its radial velocity and BV R{sub C} magnitudes. The object is known to vary in light, color, and velocity owing to pulsation with a period of 132 days. The light and color variations are accompanied by significant changes in spectral features, most of which are identified as lines of carbon-bearing molecules. According to the observations, the C{sub 2} Swan system and CN Red system lines are stronger near the light minimum. A photospheric spectrum of the central star was calculated using new self-consistent atmospheric models. The observed intensity variations in the C{sub 2} Swan system and CN Red system lines were found to be much larger than expected if due solely to the temperature variation in the atmosphere of the pulsating star. In addition, the molecular lines are blueshifted relative to the photospheric velocity. The site of formation of the strong molecular features appears to be a cool outflow triggered by the pulsation. The variability in atomic lines seems to be mostly due variations of the effective temperature during the pulsation cycle. The profiles of strong atomic lines are split, and some of them are variable in a timescale of a week or so, probably because of shock waves in the outer atmosphere.

  4. History of the solar-type protostar IRAS 16293-2422 as told by the cyanopolyynes

    NASA Astrophysics Data System (ADS)

    Jaber Al-Edhari, A.; Ceccarelli, C.; Kahane, C.; Viti, S.; Balucani, N.; Caux, E.; Faure, A.; Lefloch, B.; Lique, F.; Mendoza, E.; Quenard, D.; Wiesenfeld, L.

    2017-01-01

    Context. Cyanopolyynes are chains of carbon atoms with an atom of hydrogen and a CN group on either side. They are detected almost everywhere in the interstellar medium (ISM), as well as in comets. In the past, they have been used to constrain the age of some molecular clouds, since their abundance is predicted to be a strong function of time. Finally, cyanopolyynes can potentially contain a large portion of molecular carbon. Aims: We present an extensive study of the cyanopolyynes distribution in the solar-type protostar IRAS 16293-2422. The goals are (i) to obtain a census of the cyanopolyynes in this source and of their isotopologues; (ii) to derive how their abundance varies across the protostar envelope; and (iii) to obtain constraints on the history of IRAS 16293-2422 by comparing the observations with the predictions of a chemical model. Methods: We analysed the data from the IRAM-30 m unbiased millimeter and submillimeter spectral survey towards IRAS 16293-2422 named TIMASSS. The derived spectral line energy distribution (SLED) of each detected cyanopolyyne was compared with the predictions from the radiative transfer code GRenoble Analysis of Protostellar Envelope Spectra (GRAPES) to derive the cyanopolyyne abundances across the envelope of IRAS 16293-2422. Finally, the derived abundances were compared with the predictions of the chemical model UCL_CHEM. Results: We detect several lines from cyanoacetylene (HC3N) and cyanodiacetylene (HC5N), and report the first detection of deuterated cyanoacetylene, DC3N, in a solar-type protostar. We found that the HC3N abundance is roughly constant ( 1.3 × 10-11) in the outer cold envelope of IRAS 16293-2422, and it increases by about a factor 100 in the inner region where the dust temperature exceeds 80 K, namely when the volcano ice desorption is predicted to occur. The HC5N has an abundance similar to HC3N in the outer envelope and about a factor of ten lower in the inner region. The comparison with the chemical

  5. AKARI NEAR-INFRARED SPECTROSCOPY OF LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Lee, Jong Chul; Lee, Myung Gyoon; Hwang, Ho Seong

    2012-09-01

    We present the AKARI near-infrared (NIR; 2.5-5 {mu}m) spectroscopic study of 36 (ultra)luminous infrared galaxies ((U)LIRGs) at z = 0.01-0.4. We measure the NIR spectral features including the strengths of 3.3 {mu}m polycyclic aromatic hydrocarbon emission and hydrogen recombination lines (Br{alpha} and Br{beta}), optical depths at 3.1 and 3.4 {mu}m, and NIR continuum slope. These spectral features are used to identify optically elusive, buried active galactic nuclei (AGNs). We find that half of the (U)LIRGs optically classified as non-Seyferts show AGN signatures in their NIR spectra. Using a combined sample of (U)LIRGs with NIR spectra in the literature, we measure the contribution of buried AGNs to the infrared luminosity from the spectral energy distribution fitting to the IRAS photometry. The contribution of these buried AGNs to the infrared luminosity is 5%-10%, smaller than the typical AGN contribution of (U)LIRGs including Seyfert galaxies (10%-40%). We show that NIR continuum slopes correlate well with WISE [3.4]-[4.6] colors, which would be useful for identifying a large number of buried AGNs using the WISE data.

  6. Chandra Observations of 12 Luminous Red Quasars

    SciTech Connect

    Urrutia, T; Lacy, M; Gregg, M D; Becker, R H

    2005-03-11

    The authors present results of a study of 12 dust-reddened quasars with 0.4 < z < 2.65 and reddenings in the range 0.15 < E(B-V) < 1.7. They obtained ACIS-S X-ray spectra of these quasars, estimated the column densities towards them, and hence obtained the gas:dust ratios in the material obscuring the quasar. They detect all but one of the red quasars in the X-rays. Even though there is no obvious correlation between the X-ray determined column densities of the sources and their optical color or reddening, all of the sources show absorbed X-ray spectra. When they correct the luminosity for absorption, they can be placed among luminous quasars; therefore their objects belong to the group of high luminosity analogues of the sources contributing to the X-ray background seen in deep X-ray observations. Such sources are also found in serendipitous shallow X-ray surveys. There is a hint that the mean spectral slope of the red quasar is higher than that of normal, unobscured quasars, which could be an indication for higher accretion rates and/or an evolutionary effect. They investigate the number density of these sources compared to type 2 AGN based on the X-ray background and estimate how many moderate luminosity red quasars may be found in deep X-ray fields.

  7. VizieR Online Data Catalog: Imperial IRAS-FSC redshift catalogue (IIFSCz) (Wang+, 2009)

    NASA Astrophysics Data System (ADS)

    Wang, L.; Rowan-Robinson, M.

    2010-04-01

    We present a new catalogue, the Imperial IRAS-FSC Redshift Catalogue (IIFSCz), of 60303 galaxies selected at 60um from the IRAS Faint Source Catalogue (FSC). The IIFSCz consists of accurate position, optical, near-infrared and/or radio identifications, spectroscopic redshift (if available) or photometric redshift (if possible), predicted far-infrared (FIR) and submillimetre (submm) fluxes ranging from 12 to 1380um based upon the best-fitting infrared template. About 55% of the galaxies in the IIFSCz have spectroscopic redshifts, and a further 20% have photometric redshifts obtained through either the training set or the template-fitting method. For S(60)>0.36Jy, the 90% completeness limit of the FSC, 90% of the sources have either spectroscopic or photometric redshifts. Scientific applications of the IIFSCz include validation of current and forthcoming infrared and submm/mm surveys such as AKARI, Planck and Herschel, follow-up studies of rare source populations, large-scale structure and galaxy bias, local multiwavelength luminosity functions and source counts. The catalogue is publicly available at http://astro.imperial.ac.uk/~mrr/fss/. (2 data files).

  8. A new emission feature in IRAS spectra and the polycyclic aromatic hydrocarbon spectrum

    NASA Technical Reports Server (NTRS)

    Cohen, M.; Tielens, A. G. G. M.; Allamandola, L. J.

    1985-01-01

    IRAS spectra of those sources which show strong 7.7 and 11.3 micron emission features also show a plateau of emission extending from 11.3 to about 13.0 microns. Like the 11.3 micron feature, this new feature is attributed to the CH out-of-plane bending mode in polycyclic aromatic hydrocarbons (PAHs). Its discovery reinforces the identification of the 'unidentified infrared emission features' as emission from PAHs. The wavelength of this new feature suggests that interstellar PAHs are not as partially hydrogenated as hitherto thought. It also constrains their molecular structure.

  9. DETECTION OF C{sub 60} IN THE PROTOPLANETARY NEBULA IRAS 01005+7910

    SciTech Connect

    Zhang Yong; Kwok Sun E-mail: sunkwok@hku.hk

    2011-04-01

    We report the first detection of buckminsterfullerene (C{sub 60}) in a protoplanetary nebula. The vibrational transitions of C{sub 60} at 7.0, 17.4, and 18.9 {mu}m are detected in the Spitzer/Infrared Spectrograph spectrum of IRAS 01005+7910. This detection suggests that fullerenes are formed shortly after the asymptotic giant branch but before the planetary nebulae stage. A comparison with the observations of C{sub 60} in other sources is made and the implication for circumstellar chemistry is discussed.

  10. Research on effects of baffle position in an integrating sphere on the luminous flux measurement

    NASA Astrophysics Data System (ADS)

    Lin, Fangsheng; Li, Tiecheng; Yin, Dejin; Lai, Lei; Xia, Ming

    2016-09-01

    In the field of optical metrology, luminous flux is an important index to characterize the quality of electric light source. Currently, the majority of luminous flux measurement is based on the integrating sphere method, so measurement accuracy of integrating sphere is the key factor. There are plenty of factors affecting the measurement accuracy, such as coating, power and the position of light source. However, the baffle which is a key part of integrating sphere has important effects on the measurement results. The paper analyzes in detail the principle of an ideal integrating sphere. We use moving rail to change the relative position of baffle and light source inside the sphere. By experiments, measured luminous flux values at different distances between the light source and baffle are obtained, which we used to take analysis of the effects of different baffle position on the measurement. By theoretical calculation, computer simulation and experiment, we obtain the optimum position of baffle for luminous flux measurements. Based on the whole luminous flux measurement error analysis, we develop the methods and apparatus to improve the luminous flux measurement accuracy and reliability. It makes our unifying and transferring work of the luminous flux more accurate in East China and provides effective protection for our traceability system.

  11. A Survey for Water Maser Emission toward Planetary Nebulae: New Detection in IRAS 17347-3139

    NASA Astrophysics Data System (ADS)

    de Gregorio-Monsalvo, Itziar; Gómez, Yolanda; Anglada, Guillem; Cesaroni, Riccardo; Miranda, Luis F.; Gómez, José F.; Torrelles, José M.

    2004-02-01

    We report on a water maser survey toward a sample of 27 planetary nebulae (PNe) using the Robledo de Chavela and Medicina single-dish antennas, as well as the Very Large Array (VLA). Two detections have been obtained: the already known water maser emission in K3-35, and a new cluster of masers in IRAS 17347-3139. This low rate of detections is compatible with the short lifetime of water molecules in PNe (~100 yr). The water maser cluster at IRAS 17347-3139 are distributed on a ellipse of size ~=0.2"×0.1", spatially associated with compact 1.3 cm continuum emission (simultaneously observed with the VLA). From archive VLA continuum data at 4.9, 8.4, and 14.9 GHz, a spectral index α=0.76+/-0.03 (Sν~να) is derived for this radio source, which is consistent with either a partially optically thick ionized region or an ionized wind. However, the latter scenario can be ruled out by mass-loss considerations, thus indicating that this source is probably a young PN. The spatial distribution and the radial velocities of the water masers are suggestive of a rotating and expanding maser ring, tracing the innermost regions of a torus formed at the end of the asymptotic giant branch phase. Given that the 1.3 cm continuum emission peak is located near one of the tips of the major axis of the ellipse of masers, we speculate on a possible binary nature of IRAS 17347-3139, where the radio continuum emission could belong to one of the components and the water masers would be associated with a companion.

  12. High-resolution Observations of the Massive Protostar in IRAS 18566+0408

    NASA Astrophysics Data System (ADS)

    Hofner, P.; Cesaroni, R.; Kurtz, S.; Rosero, V.; Anderson, C.; Furuya, R. S.; Araya, E. D.; Molinari, S.

    2017-07-01

    We report 3 mm continuum, CH3CN(5-4) and 13CS(2-1) line observations with CARMA (Combined Array for Research in Millimeter-wave Astronomy), in conjunction with 6 and 1.3 cm continuum VLA data, and 12 and 25 μm broadband data from the Subaru Telescope toward the massive proto-star IRAS 18566+0408. The VLA data resolve the ionized jet into four components aligned in the E-W direction. Radio components A, C, and D have flat centimeter SEDs indicative of optically thin emission from ionized gas, and component B has a spectral index α = 1.0, and a decreasing size with frequency \\propto {ν }-0.5. Emission from the CARMA 3 mm continuum and from the 13CS(2-1) and CH3CN(5-4) spectral lines is compact (i.e., < 6700 {au}) and peaks near the position of the VLA centimeter source, component B. Analysis of these lines indicates hot and dense molecular gas, which is typical for HMCs. Our Subaru telescope observations detect a single compact source, coincident with radio component B, demonstrating that most of the energy in IRAS 18566+0408 originates from a region of size < 2400 {au}. We also present UKIRT near-infrared archival data for IRAS 18566+0408, which show extended K-band emission along the jet direction. We detect an E-W velocity shift of about 10 km s-1 over the HMC in the CH3CN lines possibly tracing the interface of the ionized jet with the surrounding core gas. Our data demonstrate the presence of an ionized jet at the base of the molecular outflow and support the hypothesis that massive protostars with O-type luminosity form with a mechanism similar to lower mass stars.

  13. An Essential Function of the N-Terminus of Ira/Neurofibromin

    DTIC Science & Technology

    2006-01-01

    conserved throughout evolution [1, 2]. The yeast S. Cerevisiae has 2 homologs, Ira1 and Ira2 [3]. These yeast Ira’s not only have extensive sequence...the haploid offspring depend on IRA1 for survival. Several heterozygous diploid strains were subjected to tetrad analysis and viability of the... haploid offspring will be scored. A 2:2 life to death segregation should be observed if IRA1 is essential for yeast. However, many tetrads yielded

  14. Not a galaxy: IRAS 04186+5143, a new young stellar cluster in the outer Galaxy

    NASA Astrophysics Data System (ADS)

    Yun, J. L.; Elia, Davide; Djupvik, A. A.; Torrelles, J. M.; Molinari, S.

    2015-09-01

    We report the discovery of a new young stellar cluster in the outer Galaxy located at the position of an IRAS Point Source Catalog source that has been previously misidentified as an external galaxy. The cluster is seen in our near-infrared imaging towards IRAS 04186+5143 and in archive Spitzer images confirming the young stellar nature of the sources detected. There is also evidence of subclustering seen in the spatial distributions of young stars and of gas and dust. Near- and mid-infrared photometry indicates that the stars exhibit colours compatible with reddening by interstellar and circumstellar dust and are likely to be low- and intermediate-mass young stellar objects (YSOs) with a large proportion of Class I YSOs. Ammonia and CO lines were detected, with the CO emission well centred near the position of the richest part of the cluster. The velocity of the CO and NH3 lines indicates that the gas is Galactic and located at a distance of about 5.5 kpc, in the outer Galaxy. Herschel data of this region characterize the dust environment of this molecular cloud core where the young cluster is embedded. We derive masses, luminosities, and temperatures of the molecular clumps where the young stars reside and discuss their evolutionary stages.

  15. IR-Radio Correlation Using the NVSS and the 1.2 Jy IRAS Catalog

    NASA Astrophysics Data System (ADS)

    Molayem, N.; Wright, E.

    1998-05-01

    We have correlated infrared fluxes in the IRAS 1.2 Jy Survey Redshift Data (Infrared Astronomical Satellite), (Fisher et al., 1997) with radio fluxes in the NVSS Source Catalog (NRAO/VLA Sky Survey), (Condon et al., 1996) in order to see whether the radio absorption by the intergalactic medium (IGM) claimed by Big Bang critic Eric Lerner actually exists. The reason that this is important is that the conventional interpretation of the cosmic background radiation (CBR) as a relic of the Big Bang assumes that the intergalactic medium (IGM) is highly transparent to radio frequency radiation. We have chosen infrared fluxes for 178 galaxies selected randomly from 3920 available sources from the 1.2 Jy IRAS catalog. The Infrared flux interval is from 1.2 Jy to 10 Jy. Their corresponding radio fluxes were taken from the NVSS source catalog. The analysis of the plot of these two luminosities shows a non-linear correlation in which the radio luminosity for a given IR luminosity is independent of distance. When a redshift dependent term is added to this correlation, the improvement in the fit is statistically insignificant.

  16. A Cluster of Class 0 Protostars in Serpens: an IRAS HIRES Study

    NASA Astrophysics Data System (ADS)

    Hurt, Robert L.; Barsony, Mary

    1996-03-01

    We present new 12, 25, 60, and 100 mu m high-resolution--processed (HIRES-processed) IRAS images of the nearby Serpens star-forming cloud core at FWHM resolutions of ~30"--1'. We use HIRES-processed point-source models of the IRAS emission to derive new flux values and flux upper limits for all the protostellar candidates in the Serpens core. Our fluxes (and flux upper limits) determine the spectral energy distributions necessary to derive the dust temperature, circumstellar mass, bolometric luminosity, and evolutionary status of each protostellar candidate. Remarkably, we find all five sources studied by Hurt, Barsony, & Wootten, FIRS 1, SMM 4, S68N, SMM 3, and SMM 2, to share the defining characteristics of class 0 protostars, the short-lived (a few times 104 yr), earliest observable protostellar stage. We can also set an upper limit of 8 L⊙ on the preoutburst bolometric luminosity of the recently discovered "FU Ori" source in this region.

  17. A Hot Molecular Outflow Driven by the Ionized Jet Associated with IRAS 16562-3959

    NASA Astrophysics Data System (ADS)

    Guzmán, Andrés E.; Garay, Guido; Brooks, Kate J.; Rathborne, Jill; Güsten, Rolf

    2011-08-01

    We report molecular line observations in the CO J = 3 → 2, 6 → 5, and 7 → 6 transitions, made using the Atacama Pathfinder Experiment Telescope, toward the massive and dense core IRAS 16562-3959. This core harbors a string of radio sources thought to be powered by a central collimated jet of ionized gas. The molecular observations show the presence of high-velocity gas exhibiting a quadrupolar morphology, most likely produced by the presence of two collimated outflows. The southeast-northwest (SE-NW) molecular outflow is aligned with the string of radio continuum sources, suggesting it is driven by the jet. We find that the excitation temperature of the gas in the SE-NW outflow is high, with values of 145 and 120 K for the blueshifted and redshifted lobes, respectively. This outflow has a total mass of 1.92 M sun, a total momentum of ~89 M sun km s-1, and an averaged momentum rate of ~3.0 × 10-2 M sun km s-1 yr-1, values characteristic of flows driven by young massive stellar objects with high luminosities (L bol ~ 2 × 104 L sun). Complementary data taken with the Atacama Submillimeter Telescope Experiment in high density and shock tracers support the picture that IRAS 16562-3959 is an accreting young massive star associated with an ionized jet, which is the energy source of a molecular outflow.

  18. Analysis of interstellar fragmentation structure based on IRAS images

    NASA Technical Reports Server (NTRS)

    Scalo, John M.

    1989-01-01

    The goal of this project was to develop new tools for the analysis of the structure of densely sampled maps of interstellar star-forming regions. A particular emphasis was on the recognition and characterization of nested hierarchical structure and fractal irregularity, and their relation to the level of star formation activity. The panoramic IRAS images provided data with the required range in spatial scale, greater than a factor of 100, and in column density, greater than a factor of 50. In order to construct a densely sampled column density map of a cloud complex which is both self-gravitating and not (yet?) stirred up much by star formation, a column density image of the Taurus region has been constructed from IRAS data. The primary drawback to using the IRAS data for this purpose is that it contains no velocity information, and the possible importance of projection effects must be kept in mind.

  19. Cryogenic infrared imaging beryllium telescope for Infrared Astronomical Satellite (IRAS)

    NASA Technical Reports Server (NTRS)

    Devereux, W. P.

    1983-01-01

    The IRAS mission is the result of an international project involving the cooperation of the U.S., the United Kingdom, and the Netherlands. The Infrared Astronmical Satellite was placed into orbit on January 25, 1983. Its main function is to provide a survey of the entire sky as viewed in four octaves of infrared radiation in the wavelenth region from 8 to 120 microns. The cylindrical structure of the satellite contains a large dewar vessel with 70 liters of superfluid helium. The helium has the function to maintain the contents of the vessel at 2.5 K for the duration of the mission. The IRAS optics is a Ritchey-Chretien telescope of 24 inches aperture. Because of the operational requirements of the mission, it had been specified that all optical components should be beryllium. Attention is given to the cold performance test conducted with IRAS, plans for future infrared telescopes, and reflectance limits.

  20. Ultraviolet properties of IRAS-selected Be stars

    NASA Technical Reports Server (NTRS)

    Bjorkman, Karen S.; Snow, Theodore P.

    1988-01-01

    New IUE observations were obtained of 35 Be stars from a list of stars which show excess infrared fluxes in IRAS data. The IRAS-selected Be stars show larger C IV and Si IV equivalent widths than other Be stars. Excess C IV and Si IV absorption seems to be independent of spectral type for IRAS-selected Be stars later than spectral type B4. This is interpreted as evidence for a possible second mechanism acting in conjunction with radiation pressure for producing the winds in Be stars. No clear correlation of IR excess of v sin i with C IV or Si IV equivalent widths is seen, although a threshold for the occurrence of excess C IV and Si IV absorption appears at a v sin i of 150 km/sec.

  1. 26 CFR 1.408A-0 - Roth IRAs; table of contents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Roth IRAs; table of contents. 1.408A-0 Section 1... (CONTINUED) INCOME TAXES Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-0 Roth IRAs; table of contents. This table of contents lists the regulations relating to Roth IRAs under section 408A of...

  2. 26 CFR 1.408A-3 - Contributions to Roth IRAs.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Contributions to Roth IRAs. 1.408A-3 Section 1... Contributions to Roth IRAs. This section sets forth the following questions and answers that provide rules regarding contributions to Roth IRAs: Q-1. What types of contributions are permitted to be made to a...

  3. 26 CFR 1.408A-0 - Roth IRAs; table of contents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Roth IRAs; table of contents. 1.408A-0 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-0 Roth IRAs; table of contents. This table of contents lists the regulations relating to Roth IRAs under section...

  4. 26 CFR 1.408A-0 - Roth IRAs; table of contents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Roth IRAs; table of contents. 1.408A-0 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-0 Roth IRAs; table of contents. This table of contents lists the regulations relating to Roth IRAs under section...

  5. 26 CFR 1.408A-4 - Converting amounts to Roth IRAs.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Converting amounts to Roth IRAs. 1.408A-4... Converting amounts to Roth IRAs. This section sets forth the following questions and answers that provide rules applicable to Roth IRA conversions: Q-1. Can an individual convert an amount in his or...

  6. 26 CFR 1.408A-0 - Roth IRAs; table of contents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Roth IRAs; table of contents. 1.408A-0 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-0 Roth IRAs; table of contents. This table of contents lists the regulations relating to Roth IRAs under section...

  7. 26 CFR 1.408A-4 - Converting amounts to Roth IRAs.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Converting amounts to Roth IRAs. 1.408A-4... Converting amounts to Roth IRAs. This section sets forth the following questions and answers that provide rules applicable to Roth IRA conversions: Q-1. Can an individual convert an amount in his or...

  8. 26 CFR 1.408A-3 - Contributions to Roth IRAs.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Contributions to Roth IRAs. 1.408A-3 Section 1... Contributions to Roth IRAs. This section sets forth the following questions and answers that provide rules regarding contributions to Roth IRAs: Q-1. What types of contributions are permitted to be made to a...

  9. 26 CFR 1.408A-0 - Roth IRAs; table of contents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Roth IRAs; table of contents. 1.408A-0 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-0 Roth IRAs; table of contents. This table of contents lists the regulations relating to Roth IRAs under section...

  10. 26 CFR 1.408A-3 - Contributions to Roth IRAs.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Contributions to Roth IRAs. 1.408A-3 Section 1... Contributions to Roth IRAs. This section sets forth the following questions and answers that provide rules regarding contributions to Roth IRAs: Q-1. What types of contributions are permitted to be made to a...

  11. 26 CFR 1.408A-3 - Contributions to Roth IRAs.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Contributions to Roth IRAs. 1.408A-3 Section 1... Contributions to Roth IRAs. This section sets forth the following questions and answers that provide rules regarding contributions to Roth IRAs: Q-1. What types of contributions are permitted to be made to a...

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Converting amounts to Roth IRAs. 1.408A-4 Section... Converting amounts to Roth IRAs. This section sets forth the following questions and answers that provide rules applicable to Roth IRA conversions: Q-1. Can an individual convert an amount in his or...

  13. 29 CFR 2509.99-1 - Interpretive Bulletin Relating to Payroll Deduction IRAs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... exercises any influence over the investments made or permitted by the IRA sponsor. (e) Administrative fees... IRA sponsor and that it does not provide any additional benefit or promise any particular investment... investments in such securities. If the IRA program were a result of an agreement between the employer and an...

  14. 29 CFR 2509.99-1 - Interpretive Bulletin Relating to Payroll Deduction IRAs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... IRA payroll deduction program clearly and prominently state, in language reasonably calculated to be... employer does not endorse or recommend either the sponsor or the funding media; that other IRA funding media are available to employees outside the payroll deduction program; that an IRA may not...

  15. Characterising Nearby Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Ramphul, R.; Vaisanen, P.; Van der Heyden, K.

    2017-06-01

    Luminous InfraRed Galaxies (LIRGs) in the local universe are known to be highly interacting galaxies with strong star-formation in obscured environments. LIRGs have diversity in terms of morphology and mode and location of SF, while their even more energetic counterparts, the Ultra-Luminous IR galaxies, ULIRGs, (LIR ≥ 10^12 Lsol ) are normally (remnants of) gas rich major mergers with centralised starbursts and AGN. I will present ongoing work on a survey of >40 (U)LIRGs, in a distance range of 40 to 300Mpc, observed with SALT/RSS in long-slit mode. The sample of galaxies are in various stages of interaction and merging, some with strong AGN contribution. The reduction of the SALT/RSS data, was performed efficiently with our custom-built pipeline written in python/iraf/pyraf and handles error-frames propagation. We are performing a rigorous stellar populations analysis of our sample using Starlight (Cid Fernandes, 2005) which will ultimately lead to understanding the star formation history of these galaxies. We also use automatic line intensity measurements to derive chemical abundances, star formation rates, metallicity and emission line diagnostic. The talk will showcase the latest results that we just obtained for this dataset and discuss some of the future works.

  16. An IRAS search for extra-solar Oort clouds

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan; Stocke, John; Weissman, Paul R.

    1991-01-01

    The presumptively close connection between Oort cloud formation and planetary formation is that the detection of comet clouds around other stars would imply the presence of extrasolar planetary systems. Low-resolution IRAS data and an S/N-enhancement method are presently used to search 17 nearby stars for comet cloud-indicating IR emission. While no such detections were obtained, upper limits have been set for extrasolar Oort clouds (ESOCs) around the candidate stars; the nondetections may be a results either of the absence of the ESOCs around these stars or, with greater probability, of the sensitivity and background confusion limitations of IRAS data.

  17. IRAS observations of extended dust envelopes around evolved stars

    NASA Technical Reports Server (NTRS)

    Hawkins, George

    1990-01-01

    Deconvolved IRAS profiles, with resolution 2-3 time better than detector sizes 1.5 and 3 arcmin at 60 and 100 microns, are presented for a number of evolved stars with extended emission. These include VY UMa, Mu Cep, S Sct, U Hya, Y CVn, U Ant, alpha Ori, Y Pav, UU aur, IRC + 10216, RZ Sgr, and R Lyr. Simple models suggest that extended IRAS emission results from stars which greater mass loss rates in the past, rather than from stars with large current mass loss rates.

  18. IRAS observations of extended dust envelopes around evolved stars

    NASA Technical Reports Server (NTRS)

    Hawkins, George

    1990-01-01

    Deconvolved IRAS profiles, with resolution 2-3 time better than detector sizes 1.5 and 3 arcmin at 60 and 100 microns, are presented for a number of evolved stars with extended emission. These include VY UMa, Mu Cep, S Sct, U Hya, Y CVn, U Ant, alpha Ori, Y Pav, UU aur, IRC + 10216, RZ Sgr, and R Lyr. Simple models suggest that extended IRAS emission results from stars which greater mass loss rates in the past, rather than from stars with large current mass loss rates.

  19. Potassium selectivity of frog gastric luminal membrane.

    PubMed

    Kasbekar, D K

    1986-06-01

    Transmural potential difference (PD) and resistance (R) changes after luminal or serosal instillation of K+ were determined under various conditions in chambered preparations of frog gastric mucosae. Potassium selectivity of the luminal membrane is indicated by the rapid reversal of the inverted PD of mucosae bathed in NaCl-free, choline sulfate (Ch2SO4)-Ringer on the serosal side and unbuffered hypertonic Ch2SO4 solution on the luminal side on luminal K+ instillation. The delta PD responses are significantly attenuated, however, in histamine-stimulated mucosae bathed in hypotonic or in burimamide-inhibited mucosae bathed in hyper- and hypotonic luminal media, which suggests that the K+ selectivity of the luminal membrane resides largely in the tubular cell apical membrane. Imposing a serosal-to-luminal transmucosal K+ gradient in both histamine-stimulated and omeprazole-inhibited mucosae also reversed the normal orientation of PD but not in those inhibited with burimamide. In the latter, the PD inversion was attenuated but maintained its normal orientation. These data suggest that burimamide, but not omeprazole, acts by blocking luminal membrane K+ conductance. The inverted PD in mucosae bathed in Cl-free media may thus be due partially or fully to K+ diffusion driven by the cell-to-lumen K+ gradient via the luminal K+ conductance pathway. These findings have implications for the controversy surrounding the postulated electrogenicity of the gastric proton pump.

  20. Astronomy. ASASSN-15lh: A highly super-luminous supernova.

    PubMed

    Dong, Subo; Shappee, B J; Prieto, J L; Jha, S W; Stanek, K Z; Holoien, T W-S; Kochanek, C S; Thompson, T A; Morrell, N; Thompson, I B; Basu, U; Beacom, J F; Bersier, D; Brimacombe, J; Brown, J S; Bufano, F; Chen, Ping; Conseil, E; Danilet, A B; Falco, E; Grupe, D; Kiyota, S; Masi, G; Nicholls, B; Olivares E, F; Pignata, G; Pojmanski, G; Simonian, G V; Szczygiel, D M; Woźniak, P R

    2016-01-15

    We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu ,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10(45) ergs s(-1), which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10(52) ergs, challenging the magnetar model for its engine. Copyright © 2016, American Association for the Advancement of Science.

  1. ASASSN-15lh: A highly super-luminous supernova

    NASA Astrophysics Data System (ADS)

    Dong, Subo; Shappee, B. J.; Prieto, J. L.; Jha, S. W.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Thompson, T. A.; Morrell, N.; Thompson, I. B.; Basu, U.; Beacom, J. F.; Bersier, D.; Brimacombe, J.; Brown, J. S.; Bufano, F.; Chen, Ping; Conseil, E.; Danilet, A. B.; Falco, E.; Grupe, D.; Kiyota, S.; Masi, G.; Nicholls, B.; Olivares E., F.; Pignata, G.; Pojmanski, G.; Simonian, G. V.; Szczygiel, D. M.; Woźniak, P. R.

    2016-01-01

    We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 1045 ergs s-1, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 1052 ergs, challenging the magnetar model for its engine.

  2. The NIST Detector-Based Luminous Intensity Scale

    PubMed Central

    Cromer, C. L.; Eppeldauer, G.; Hardis, J. E.; Larason, T. C.; Ohno, Y.; Parr, A. C.

    1996-01-01

    The Système International des Unités (SI) base unit for photometry, the candela, has been realized by using absolute detectors rather than absolute sources. This change in method permits luminous intensity calibrations of standard lamps to be carried out with a relative expanded uncertainty (coverage factor k = 2, and thus a 2 standard deviation estimate) of 0.46 %, almost a factor-of-two improvement. A group of eight reference photometers has been constructed with silicon photodiodes, matched with filters to mimic the spectral luminous efficiency function for photopic vision. The wide dynamic range of the photometers aid in their calibration. The components of the photometers were carefully measured and selected to reduce the sources of error and to provide baseline data for aging studies. Periodic remeasurement of the photometers indicate that a yearly recalibration is required. The design, characterization, calibration, evaluation, and application of the photometers are discussed. PMID:27805119

  3. The Dense Molecular Gas and Nuclear Activity in the Local ULIRG IRAS 13120-5453

    NASA Astrophysics Data System (ADS)

    Privon, George C.; Aalto, Susanne; Falstad, Niklas; Muller, Sebastien; González-Alfonso, Eduardo; Sliwa, Kazimierz; Treister, Ezequiel; Costagliola, Francesco; Armus, Lee; Evans, Aaron S.; Garcia-Burillo, Santiago; Izumi, Takuma; Sakamoto, Kazushi; van der Werf, Paul

    2017-01-01

    Ultraluminous infrared galaxies (ULIRGs) are the most luminous and concentrated star-forming galaxies in the local Universe. With a galaxy's worth of gas in the central kiloparsec and star formation rates in excess of 100 solar masses per year, these systems can have infrared surface densities that approach predictions for radiation pressure-limited starbursts. We will present a case study of a local ULIRG, IRAS 13120-5453, using ALMA observations of dense gas tracers HCN and HCO+, and the 330 GHz continuum emission. We find the HCN/HCO+ ratio to be elevated above typical values for star-forming galaxies and suggest the enhancement can be explained by increased HCN abundance driven by mechanical heating from supernovae in the starburst. The 330 GHz continuum size is resolved, with a size of ~500 pc. Using this as a measure of the starburst size, we show the IR luminosity surface density is below that for a radiation pressure-limited starburst. We also find tentative evidence for non-virial motions of HCN, suggesting dense molecular gas may be entrained the molecular wind (previously detected in OH).

  4. IRAS-based whole-sky upper limit on Dyson Spheres

    SciTech Connect

    Carrigan, Richard A., Jr.; /Fermilab

    2008-09-01

    A Dyson Sphere is a hypothetical construct of a star purposely cloaked by a thick swarm of broken-up planetary material to better utilize all of the stellar energy. A clean Dyson Sphere identification would give a significant signature for intelligence at work. A search for Dyson Spheres has been carried out using the 250,000 source database of the IRAS infrared satellite which covered 96% of the sky. The search has used the Calgary data collection of the IRAS Low Resolution Spectrometer (LRS) to look for fits to blackbody spectra. Searches have been conducted for both pure (fully cloaked) and partial Dyson Spheres in the blackbody temperature region 100 {le} T {le} 600 K. Other stellar signatures that resemble a Dyson Sphere are reviewed. When these signatures are used to eliminate sources that mimic Dyson Spheres very few candidates remain and even these are ambiguous. Upper limits are presented for both pure and partial Dyson Spheres. The sensitivity of the LRS was enough to find solar-sized Dyson Spheres out to 300 pc, a reach that encompasses a million solar-type stars.

  5. The compact far infrared emission from the young stellar object IRAS 16293-2422

    NASA Technical Reports Server (NTRS)

    Butner, Harold M.; Evans, N. J., III; Lester, D. F.; Mundy, L. G.; Harvey, P. M.; Campbell, M. F.

    1989-01-01

    High resolution far IR observations at 50 and 100 microns were made of the young stellar object (YSO), IRAS 16293-2422. The observations are part of a systematic high resolution study of nearby YSO's. The purpose is to obtain resolution in the far IR comparable to that at other wavelengths. Until recently, the high resolution that has been available in the far IR has been from either IRAS (angular resolution of approx 4 min) or the KAO using standard FIR photometry (approx 35 sec). With scanning techniques, it is possible to obtain 10 sec resolution on bright sources. Such a resolution is necessary to better determine the physical conditions of the YSO, and to compare with model of star formation. In order to better constrain the models for the source, the YSO was observed at both 50 and 100 microns on several flights in 1988 April from the KAO. Estimates are presented of the size both along the major and minor axis of the disk, as well as estimates of the dust temperature and 100 micron opacity for the YSO.

  6. A remarkable multilobe molecular outflow - Rho Ophiuchi East, associated with IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Mizuno, A.; Fukui, Y.; Iwata, T.; Nozawa, S.; Takano, T.

    1990-06-01

    Rho Ophiuchi East is one of the molecular outflows discovered in the Nagoya CO survey of star formation regions (Fukui et al., 1986) and was independently discovered by Wootten and Loren (1987). IRAS 16293-2422 is the driving source of the outflow. A detailed observational study of this outflow source in the J = 1-0 and J = 2-1 transitions of CO and in the (J, K) = (1, 1) and (2, 2) transitions of NH3 was made with angular resolutions of 17-80 arcsecs. The high-velocity CO emission has been resolved into four compact separate lobes, consisting of two pairs of bipolar lobes, in addition to an extended monopolar blueshifted lobe. The NH3 cloud has a size of 2.5 x 2.5 arcmin being peaked at 1.7 arcmin east of IRAS 16293-2422. This NH3 peak is located just toward the edge of one of the compact blue CO lobes, showing a blueshift of 0.5 km/s from the rest of the NH3 cloud. The momentum involved in the NH3 peak is nearly equal to that of the CO lobe. It is suggested that the CO lobe has dynamically interacted with the NH3 core, resulting in the acceleration of the NH3 core by 0.5 km/s.

  7. MILLIMETRIC AND SUBMILLIMETRIC OBSERVATIONS OF IRAS 05327+3404 ''HOLOEA'' IN M36

    SciTech Connect

    Morata, O.; Ho, P. T. P.; Kuan, Y.-J.; Huang, H.-C.; Zhao-Geisler, R.; Magnier, E. A.

    2013-09-15

    The transition between the protostar, Class I, and the pre-main-sequence star, Class II, phases is still one of the most uncertain, and important, stages in the knowledge of the process of formation of an individual star because it is the stage that determines the final mass of the star. We observed the young stellar object ''Holoea'', associated with IRAS 05327+3404, which was classified as an object in the transition between the Class I and Class II phases with several unusual properties, and appears to be surrounded by large amounts of circumstellar material. We used the SMA and BIMA telescopes at millimeter and submillimeter (submm) wavelengths to observe the dust continuum emission and the CO (1-0) and (2-1), HCO{sup +} (1-0) and (3-2), and HCN (1-0) transitions in the region around IRAS 05327+3404. We detected two continuum emission peaks at 1.1 mm: SMM 1, the submm counterpart of IRAS 05327+3404, and SMM 2, {approx}6 arcsec to the west. The emissions of the three molecules show marked differences. The CO emission near the systemic velocity is filtered out by the telescopes, and CO mostly traces the high-velocity gas. The HCO{sup +} and HCN emissions are more concentrated around the central parts of the region, and show several intensity peaks coincident with the submm continuum peaks. We identify two main molecular outflows: a bipolar outflow in an E-W direction that would be powered by SMM 1 and the other in a NE direction, which we associate with SMM 2. We propose that the SMM sources are probably Class I objects, with SMM 1 in an earlier evolutionary stage.

  8. Active galactic nucleus torus models and the puzzling infrared spectrum of IRAS F10214+4724

    NASA Astrophysics Data System (ADS)

    Efstathiou, A.; Christopher, N.; Verma, A.; Siebenmorgen, R.

    2013-12-01

    We present a revised model for the infrared emission of the hyperluminous infrared galaxy IRAS F10214+4724 which takes into account recent photometric data from Spitzer and Herschel that sample the peak of its spectral energy distribution. We first present and discuss a grid of smooth active galactic nucleus (AGN) torus models computed with the method of Efstathiou & Rowan-Robinson and demonstrate that the combination of these models and the starburst models of Efstathiou and coworkers, while able to give an excellent fit to the average spectrum of Seyfert 2s and spectra of individual type 2 quasars measured by Spitzer, fails to match the spectral energy distribution of IRAS F10214+4724. This is mainly due to the fact that the νSν distribution of the galaxy falls very steeply with increasing frequency (a characteristic that is usually indicative of heavy absorption by dust) but shows a silicate feature in emission. Such emission features are not expected in sources with optical/near-infrared type 2 AGN spectral signatures. The Herschel data show that there is more power emitted in the rest-frame 20-50 μm wavelength range compared with the model presented by Efstathiou which assumes three components of emission: an edge-on torus, clouds (at a temperature of 610 and 200 K) that are associated with the narrow-line region (NLR) and a highly obscured starburst that dominates in the submillimetre. We present a revised version of that model that assumes an additional component of emission which we associate with NLR clouds at a temperature of 100 K. The 100 K dust component could also be explained by a highly obscured hot starburst. The model suggests that the NLR of IRAS F10214+4724 has an unusually high covering factor (≥17 per cent) or more likely the magnification of the emission from the NLR clouds is significantly higher than that of the emission from the torus.

  9. A Dynamical Model of a Still-Forming Zodiacal Dust Band, as Constrained by IRAS Data

    NASA Astrophysics Data System (ADS)

    Espy, Ashley J.; Dermott, S. F.; Kehoe, T. J. J.

    2009-05-01

    When an asteroid is disrupted, the larger pieces remain on similar orbits and constitute an asteroid family. The smaller products of the disruption (10 microns- a few cm) decay into the inner solar system under the effect of Poynting-Roberston drag. Before these particles encounter the secular and mean-motion resonances at the inner edge of the main belt, they retain their proper orbital elements and share common forced elements, allowing for the existence of the dust band structure discovered by IRAS (Low et al., 1984). There are currently known to be at least three dust band pairs associated with relatively young (≤ 107 yr old) asteroidal disruptions (Grogan et al., 2001; Dermott et al., 2002; Nesvorny et al., 2003; 2008). A method of coadding the IRAS data set, revealed the existence of an additional solar system dust band at 17 degrees inclination, likely a confirmation of the M/N pair originally suggested by Sykes (1988). We see this new dust band at some but not all ecliptic longitudes, providing strong evidence for a very young dust band in the process of formation. In order to determine the parent body of this band, we create a full dynamical model of the formation of this dust band to constrain the parameters of a source body capable of producing the structure. The model is based on the dynamical evolution of the 10-1000 micron diameter dust particles from the disruption event. Comparison of the model to our co-added IRAS observations allows us to put bounds on the parameters of the parent body, including the node location and dispersion, which gives an age to the disruption that produced the partial band. We also investigate the effects that varying the orbital parameters has on the timescale and formation of a band pair.

  10. In Search of the Youngest Protostars: IRAS HIRES Results in the Serpens Cloud Core

    NASA Astrophysics Data System (ADS)

    Hurt, R. L.; Barsony, M.

    1995-12-01

    Protostars which have yet to accrete the bulk of their initial main sequence mass from their infall envelopes, dubbed ``Class 0'' (Andre, Ward-Thompson, & Barsony 1993), represent the youngest (a few x 10(4) yr) protostellar sources. The defining observational characteristics for Class 0 protostars include a high ratio of mm/submm to bolometric luminosity, the presence of molecular outflows, invisibility shortward of 10 mu m, and spectral energy distributions (SEDs) resembling modified blackbodies with T <= 30 K. Since Class 0 SEDs peak at ~ 100--200 mu m, far-infrared (FIR) data are required to produce SEDs for these sources. The nearby Serpens star-forming cloud core is a region of great interest for Class 0 protostar searches. Millimeter continuum maps of the central 6(') x 5(') reveal at least five cold dust continuum peaks which lack NIR counterparts (Casali, Eiroa, & Duncan 1993). A recent multi-transition H_2CO study of these millimeter continuum sources (FIRS1, SMM2, SMM3, SMM4, & S68N) confirms the presence of central heating sources and substantial masses of circumstellar gas in these objects, suggesting that they could all be Class 0 protostars (Hurt, Barsony & Wooten 1996). We present new 12, 25, 60, & 100 mu m HIRES processed IRAS images of the Serpens cloud core at FWHM resolutions of ~ 30('') --1(') . Such resolutions are necessary to help identify the individual contributions from the closely spaced sources. We use HIRES-processed point source models of the IRAS emission to determine new flux values and flux upper limits for all the protostellar candidates in the Serpens core. From the resulting SEDs we derive the dust temperature, circumstellar mass, bolometric luminosity, and evolutionary status of each protostellar candidate. Remarkably, we find all five millimeter continuum sources to share the defining characteristics of Class 0 protostars, potentially making the Serpens core the densest known collection of such objects.

  11. VizieR Online Data Catalog: ATLASGAL clumps with IRAS flux and MALT90 data (Stephens+, 2016)

    NASA Astrophysics Data System (ADS)

    Stephens, I. W.; Jackson, J. M.; Whitaker, J. S.; Contreras, Y.; Guzman, A. E.; Sanhueza, P.; Foster, J. B.; Rathborne, J. M.

    2016-08-01

    The Millimetre Astronomy Legacy Team 90GHz (MALT90) survey (Foster+ 2011, J/ApJS/197/25; 2013PASA...30...38F; Jackson+ 2013PASA...30...57J) mapped 16 lines for 3246 clumps, primarily high-mass star-forming clumps that are >200M⊙, as identified from the ATLASGAL 870um survey (Schuller et al. 2009A&A...504..415S). In order to compare luminosities derived from IRAS (LIR) to molecular line luminosities from MALT90 (Lmolecule), we first matched the MALT90 clumps to the IRAS Point Source Catalog v2.1 (PSC; see Cat. II/125). See section 2.1 for further explanations. (1 data file).

  12. Molecular abundances and low-mass star formation. 1: Si- and S-bearing species toward IRAS 16293-2422

    NASA Technical Reports Server (NTRS)

    Blake, Geoffrey A.; Dishoek, Ewine F. Van; Jansen, David J.; Groesbeck, T. D.; Mundy, Lee G.

    1994-01-01

    Results from millimeter and submillimeter spectral line surveys of the protobinary source Infrared Astronomical Satellite (IRAS) 16293-2422 are presented. Here we outline the abundances of silicon- and sulfur-containing species. A combination of rotation diagram and full statistical equilibrium/radiative transfer calculations is used to constrain the physical conditions toward IRAS 16293 and to construct its beam-averaged chemical composition over a 10 to 20 sec (1600 to 3200 AU) scale. The chemical complexity as judged by species such as SiO, OCS, and H2S, is intermediate between that of dark molecular clouds such as L134N and hot molecular cloud cores such as Orion KL. From the richness of the spectra compared to other young stellar objects of similar luminosity, it is clear that molecular abundances do not scale simply with mass; rather, the chemistry is a strong function of evolutionary state, i.e., age.

  13. Preliminary scientific results from the first six months of the Infrared Astronomical Satellite (IRAS)

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.; Neugebauer, G.; Beichman, C. A.; Houck, J. R.; Rowan-Robinson, M.

    1984-01-01

    The Infrared Astronomical Satellite (IRAS) was successfully launched on January 25, 1983. This paper presents results based on analysis of early scientific data returned from IRAS. Among the early results of IRAS are the discovery of comet IRAS-Araki-Alcock, evidence for a shell of large particles around the nearby bright star Vega, detection of stars in the process of formation, and detection of many infrared bright galaxies. These early results demonstrate that the IRAS data will be a treasure chest for astronomers for years to come.

  14. U.S. data processing for the IRAS project. [by Jet Propulsion Laboratory Scientific Data Analysis System

    NASA Technical Reports Server (NTRS)

    Duxbury, J. H.

    1983-01-01

    The JPL's Scientific Data Analysis System (SDAS), which will process IRAS data and produce a catalogue of perhaps a million infrared sources in the sky, as well as other information for astronomical records, is described. The purposes of SDAS are discussed, and the major SDAS processors are shown in block diagram. The catalogue processing is addressed, mentioning the basic processing steps which will be applied to raw detector data. Signal reconstruction and conversion to astrophysical units, source detection, source confirmation, data management, and survey data products are considered in detail.

  15. VLA Ammonia Observations of IRAS 16253-2429: A Very Young and Low Mass Protostellar System

    NASA Technical Reports Server (NTRS)

    Wiseman, Jennifer J.

    2011-01-01

    IRAS l6253-2429. the source of the Wasp-Waist Nebula seen in Spitzer IRAC images, is an isolated very low luminosity ("VeLLO") Class 0 protostar in the nearby rho Ophiuchi cloud. We present VLA ammonia mapping observations of the dense gas envelope feeding the central core accreting system. We find a flattened envelope perpendicular to the outflow axis, and gas cavities that appear to cradle the outflow lobes as though carved out by the flow and associated (apparently precessing) jet. Based on the NH3 (1,1) and (2,2) emission distribution, we derive the mass, velocity fields and temperature distribution for the envelope. We discuss the combined evidence for this source as possibly one of the youngest and lowest mass sources in formation yet known.

  16. IRAS observations of dust heating and energy balance in the Rho Ophiuchi dark cloud

    NASA Technical Reports Server (NTRS)

    Greene, Thomas P.; Young, Erick T.

    1989-01-01

    The equilibrium process dust emission in the Rho Ophiuchi dark cloud is studied. The luminosity of the cloud is found to closely match the luminosity of the clouds's known embedded and external radiation sources. There is no evidence for a large population of undetected low-luminosity sources within the cloud and unknown external heating is also only a minor source of energy. Most of the cloud's luminosity is emitted in the mid-to-far-IR. Dust temperature maps indicate that the dust is not hot enough to heat the gas to observed temperatures. A simple cloud model with a radiation field composed of flux HD 147889, S1, and Sco OB2 associations predicts the observed IRAS 60 to 100 micron in-band flux ratios for a mean cloud density n(H2) = 1400. Flattened 12 and 25 micron observations show much extended emission in these bands, suggesting stochastic heating of very small grains or large molecules.

  17. A very deep IRAS survey - Constraints on the evolution of starburst galaxies

    NASA Astrophysics Data System (ADS)

    Hacking, Perry; Condon, J. J.; Houck, J. R.

    1987-05-01

    Counts of sources (primarily starburst galaxies) from a deep 60 microns IRAS survey published by Hacking and Houck (1987) are compared with four evolutionary models. The counts below 100 mJy are higher than expected if no evolution has taken place out to a redshift of approximately 0.2. Redshift measurements of the survey sources should be able to distinguish between luminosity-evolution and density-evolution models and detect as little as a 20 percent brightening or increase in density of infrared sources per billion years ago (H/0/ = 100 km/s per Mpc). Starburst galaxies cannot account for the reported 100 microns background without extreme evolution at high redshifts.

  18. IRAS observations of dust heating and energy balance in the Rho Ophiuchi dark cloud

    NASA Technical Reports Server (NTRS)

    Greene, Thomas P.; Young, Erick T.

    1989-01-01

    The equilibrium process dust emission in the Rho Ophiuchi dark cloud is studied. The luminosity of the cloud is found to closely match the luminosity of the clouds's known embedded and external radiation sources. There is no evidence for a large population of undetected low-luminosity sources within the cloud and unknown external heating is also only a minor source of energy. Most of the cloud's luminosity is emitted in the mid-to-far-IR. Dust temperature maps indicate that the dust is not hot enough to heat the gas to observed temperatures. A simple cloud model with a radiation field composed of flux HD 147889, S1, and Sco OB2 associations predicts the observed IRAS 60 to 100 micron in-band flux ratios for a mean cloud density n(H2) = 1400. Flattened 12 and 25 micron observations show much extended emission in these bands, suggesting stochastic heating of very small grains or large molecules.

  19. Very deep IRAS survey - constraints on the evolution of starburst galaxies

    SciTech Connect

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

    1987-05-01

    Counts of sources (primarily starburst galaxies) from a deep 60 microns IRAS survey published by Hacking and Houck (1987) are compared with four evolutionary models. The counts below 100 mJy are higher than expected if no evolution has taken place out to a redshift of approximately 0.2. Redshift measurements of the survey sources should be able to distinguish between luminosity-evolution and density-evolution models and detect as little as a 20 percent brightening or increase in density of infrared sources per billion years ago (H/0/ = 100 km/s per Mpc). Starburst galaxies cannot account for the reported 100 microns background without extreme evolution at high redshifts. 21 references.

  20. A Starfish Preplanetary Nebula: IRAS 19024+0044

    NASA Technical Reports Server (NTRS)

    Sahai, Raghvendra; Sanchez Contreras, Carmen; Morris, Mark

    2005-01-01

    Using the Hubble Space Telescope, we have imaged the OH/IR star IRAS 19024+0044 (I19024) at 0.6, 0.8, 1.1, and 1.6 micrometers, as part of our surveys of candidate preplanetary nebulae. The images show a multipolar nebula of size approximately equal to 3.'7 2.'3, with at least six elongated lobes emanating from the center of the nebula. Two of the lobes show limb-brightened tips having point-symmetric structure with respect to the expected location of the central star. The central region shows two dark bands southwest and northeast of a central shallow maximum that may be either two inclined dusty toroidal structures or the dense parts of a single wide, inhomogeneous, toroid. Avery faint, surface brightness-limited, diffuse halo surrounds the lobes. Long-slit/echelle optical spectroscopy obtained at the Mount Palomar and Keck observatories shows a spatially compact source of H(alpha) emission; the H(alpha) line shows a strong, narrow, central core with very broad (+/-1000 km/sec), weak wings, and a narrower blueshifted absorption feature signifying the presence of an approximately 100 km/sec(exp -1) outflow. The spectrum is characterized by a strong, relatively featureless, continuum and lacks the strong forbidden emission lines characteristic of planetary nebulae, confirming that IRAS 19024 is a preplanetary nebula; the spectral type for the central star, although uncertain, is most likely early G. Interferometric observations of the CO J = 1 -0 line emission with the Owens Valley Radio Interferometer show a marginally resolved molecular envelope (size 5.'5 x 4.'4) with an expansion velocity of 13 km/sec (exp -1), resulting from the asymptotic giant branch (AGB) progenitor's dense, slow wind. We derive a kinematic distance of 3.5 kpc to I19024, based on its radial velocity. The bolometric flux is 7:3 x 10(exp -9) erg s(exp -1) cm(exp -2), and the luminosity 2850 L. The relatively low luminosity of I19024, in comparison with stellar evolutionary models, indicates

  1. A Starfish Preplanetary Nebula: IRAS 19024+0044

    NASA Technical Reports Server (NTRS)

    Sahai, Raghvendra; Sanchez Contreras, Carmen; Morris, Mark

    2005-01-01

    Using the Hubble Space Telescope, we have imaged the OH/IR star IRAS 19024+0044 (I19024) at 0.6, 0.8, 1.1, and 1.6 micrometers, as part of our surveys of candidate preplanetary nebulae. The images show a multipolar nebula of size approximately equal to 3.'7 2.'3, with at least six elongated lobes emanating from the center of the nebula. Two of the lobes show limb-brightened tips having point-symmetric structure with respect to the expected location of the central star. The central region shows two dark bands southwest and northeast of a central shallow maximum that may be either two inclined dusty toroidal structures or the dense parts of a single wide, inhomogeneous, toroid. Avery faint, surface brightness-limited, diffuse halo surrounds the lobes. Long-slit/echelle optical spectroscopy obtained at the Mount Palomar and Keck observatories shows a spatially compact source of H(alpha) emission; the H(alpha) line shows a strong, narrow, central core with very broad (+/-1000 km/sec), weak wings, and a narrower blueshifted absorption feature signifying the presence of an approximately 100 km/sec(exp -1) outflow. The spectrum is characterized by a strong, relatively featureless, continuum and lacks the strong forbidden emission lines characteristic of planetary nebulae, confirming that IRAS 19024 is a preplanetary nebula; the spectral type for the central star, although uncertain, is most likely early G. Interferometric observations of the CO J = 1 -0 line emission with the Owens Valley Radio Interferometer show a marginally resolved molecular envelope (size 5.'5 x 4.'4) with an expansion velocity of 13 km/sec (exp -1), resulting from the asymptotic giant branch (AGB) progenitor's dense, slow wind. We derive a kinematic distance of 3.5 kpc to I19024, based on its radial velocity. The bolometric flux is 7:3 x 10(exp -9) erg s(exp -1) cm(exp -2), and the luminosity 2850 L. The relatively low luminosity of I19024, in comparison with stellar evolutionary models, indicates

  2. Apparent speed increases at low luminance

    PubMed Central

    Vaziri-Pashkam, Maryam; Cavanagh, Patrick

    2009-01-01

    To investigate the effect of luminance on apparent speed, subjects adjusted the speed of a low-luminance rotating grating (0.31 cd/m2) to match that of a high-luminance one (1260 cd/m2). Above 4 Hz, subjects overestimated the speed of the low-luminance grating. This overestimation increased as a function of temporal rate and reached 30% around 10 Hz temporal rates. The speed overestimation became significant once the lower luminance was 2.4 log units lower than the high luminance comparison. Next the role of motion smear in speed overestimation was examined. First it was shown that the length of the perceived motion smear increased at low luminances. Second, the length of the visible smear was manipulated by changing the presentation time of the stimuli. Speed overestimation was reduced at shorter presentation times. Third the speed of a blurred stimulus was compared to a stimulus with sharp edges and the blurred stimulus was judged to move faster. These results indicate that the length of motion smear following a target contributes to its perceived speed and that this leads to speed overestimation at low luminance where motion traces lengthen because of increased persistence. PMID:19146275

  3. The distribution of IRAS galaxies towards the Bootes void

    NASA Technical Reports Server (NTRS)

    Strauss, Michael A.; Huchra, John

    1988-01-01

    A redshift survey was completed for 342 galaxies detected by the IRAS in the direction of the Bootes void discovered by Kirshner et al. The number density of IRAS galaxies is well determined from the shallower full-sky redshift survey of Strauss et al. Four IRAS galaxies are found within the void as defined by Kirshner et al., of which three are part of a complete sample, implying a density depression of a factor of 4. The underdense region continues to a distance of at least 4000 km/s from the nominal center of the void. Three of the IRAS galaxies studied in this paper were previously unknown. These galaxies have emission-line spectra characteristic of H II regions, and red continuum magnitudes ranging from 16 to 17.5 mag, and thus are bright enough to have been detected in a wide-angle redshift survey as deep as that of Kirshner et al. The luminosity function derived from this sample is in good agreement with that of Lawrence et al.

  4. IRAS 20050+2720: ANATOMY OF A YOUNG STELLAR CLUSTER

    SciTech Connect

    Guenther, H. M.; Wolk, S. J.; Spitzbart, B.; Forbrich, J.; Wright, N. J.; Bourke, T. L.; Gutermuth, R. A.; Allen, L.; Megeath, S. T.; Pipher, J. L.

    2012-10-01

    IRAS 20050+2720 is young star-forming region at a distance of 700 pc without apparent high-mass stars. We present results of our multi-wavelength study of IRAS 20050+2720 which includes observations by Chandra and Spitzer, and Two Micron All Sky Survey and UBVRI photometry. In total, about 300 young stellar objects (YSOs) in different evolutionary stages are found. We characterize the distribution of YSOs in this region using a minimum spanning tree analysis. We newly identify a second cluster core, which consists mostly of class II objects, about 10' from the center of the cloud. YSOs of earlier evolutionary stages are more clustered than more evolved objects. The X-ray luminosity function (XLF) of IRAS 20050+2720 is roughly lognormal, but steeper than the XLF of the more massive Orion Nebula complex. IRAS 20050+2720 shows a lower N{sub H}/A{sub K} ratio compared with the diffuse interstellar medium.

  5. Some new luminance-gradient effects.

    PubMed

    Zavagno, D

    1999-01-01

    Three compelling luminance-gradient effects are described. The first effect concerns a brightness enhancement and a luminous mist spreading out from a central area having the same luminance as the white background and surrounded by four rectangular inducers shaded with a linear luminance gradient. The second effect is perceived with a photographically reversed configuration, and concerns what may be considered a brightness reduction or the enhancement of a darkness quality of a target area of the visual scene. The third effect concerns the perception of a self-luminous disk inside a somewhat foggy medium. The effects are worthy of further examination because they challenge current theories of luminosity perception and brightness perception in general.

  6. Perception of chromatic motion requires luminance interaction.

    PubMed

    Baraas, Rigmor C

    2005-01-01

    There is an ongoing debate related to whether chromatic motion perception arises as a consequence of a chromatic signal only (eg Wandell et al 1999 Neuron 24 901-909) or a signal that is essentially based on luminance processes (luminance artifacts) (Mullen et al 2003 Vision Research 43 1235-1247). These two views conform to the idea that colour and luminance processes are physiologically independent (Livingstone and Hubel 1988 Science 240 740-749), but according to other reports many primary cortical 'V1' cells respond to both colour and luminance contrast (eg Vidyasagar et al 2002 European Journal of Neuroscience 16 945-956). A psychophysical task was designed to test whether possible interaction between luminance and chromatic contrast could account for perception of chromatic motion. It is shown that subjects respond in a manner that reflects involvement of both processes.

  7. Reverse radiance: a fast accurate method for determining luminance

    NASA Astrophysics Data System (ADS)

    Moore, Kenneth E.; Rykowski, Ronald F.; Gangadhara, Sanjay

    2012-10-01

    Reverse ray tracing from a region of interest backward to the source has long been proposed as an efficient method of determining luminous flux. The idea is to trace rays only from where the final flux needs to be known back to the source, rather than tracing in the forward direction from the source outward to see where the light goes. Once the reverse ray reaches the source, the radiance the equivalent forward ray would have represented is determined and the resulting flux computed. Although reverse ray tracing is conceptually simple, the method critically depends upon an accurate source model in both the near and far field. An overly simplified source model, such as an ideal Lambertian surface substantially detracts from the accuracy and thus benefit of the method. This paper will introduce an improved method of reverse ray tracing that we call Reverse Radiance that avoids assumptions about the source properties. The new method uses measured data from a Source Imaging Goniometer (SIG) that simultaneously measures near and far field luminous data. Incorporating this data into a fast reverse ray tracing integration method yields fast, accurate data for a wide variety of illumination problems.

  8. MID-INFRARED PROPERTIES OF NEARBY LUMINOUS INFRARED GALAXIES. I. SPITZER INFRARED SPECTROGRAPH SPECTRA FOR THE GOALS SAMPLE

    SciTech Connect

    Stierwalt, S.; Armus, L.; Surace, J. A.; Inami, H.; Petric, A. O.; Diaz-Santos, T.; Haan, S.; Howell, J.; Marshall, J.; Charmandaris, V.; Kim, D. C.; Mazzarella, J. M.; Chan, B.; Spoon, H. W. W.; Veilleux, S.; Evans, A.; Sanders, D. B.; Appleton, P.; Bothun, G.; Bridge, C. R.; and others

    2013-05-01

    The Great Observatories All-Sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here we present low resolution Spitzer Infrared Spectrograph spectra covering 5-38 {mu}m and provide a basic analysis of the mid-IR spectral properties observed for nearby LIRGs. In a companion paper, we discuss detailed fits to the spectra and compare the LIRGs to other classes of galaxies. The GOALS sample of 244 nuclei in 180 luminous (10{sup 11} {<=} L {sub IR}/L {sub Sun} < 10{sup 12}) and 22 ultraluminous (L {sub IR}/L {sub Sun} {>=} 10{sup 12}) IR galaxies represents a complete subset of the IRAS Revised Bright Galaxy Sample and covers a range of merger stages, morphologies, and spectral types. The majority (>60%) of the GOALS LIRGs have high 6.2 {mu}m polycyclic aromatic hydrocarbon (PAH) equivalent widths (EQW{sub 6.2{mu}m} > 0.4 {mu}m) and low levels of silicate absorption (s {sub 9.7{mu}m} > -1.0). There is a general trend among the U/LIRGs for both silicate depth and mid-infrared (MIR) slope to increase with increasing L {sub IR}. U/LIRGs in the late to final stages of a merger also have, on average, steeper MIR slopes and higher levels of dust obscuration. Together, these trends suggest that as gas and dust is funneled toward the center of a coalescing merger, the nuclei become more compact and more obscured. As a result, the dust temperature increases also leading to a steeper MIR slope. The sources that depart from these correlations have very low PAH equivalent width (EQW{sub 6.2{mu}m} < 0.1 {mu}m) consistent with their emission being dominated by an active galactic nucleus (AGN) in the MIR. These extremely low PAH EQW sources separate into two distinct types: relatively unobscured sources with a very hot dust component (and thus very shallow MIR slopes) and heavily dust obscured nuclei with a steep temperature gradient. The most heavily dust obscured sources are also the most compact in their MIR

  9. Moderately luminous Type II supernovae

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Pastorello, A.; Turatto, M.; Pumo, M. L.; Benetti, S.; Cappellaro, E.; Botticella, M. T.; Bufano, F.; Elias-Rosa, N.; Harutyunyan, A.; Taubenberger, S.; Valenti, S.; Zampieri, L.

    2013-07-01

    Context. Core-collapse Supernovae (CC-SNe) descend from progenitors more massive than about 8 M⊙. Because of the young age of the progenitors, the ejecta may eventually interact with the circumstellar medium (CSM) via highly energetic processes detectable in the radio, X-ray, ultraviolet (UV) and, sometimes, in the optical domains. Aims: In this paper we present ultraviolet, optical and near infrared observations of five Type II SNe, namely SNe 2009dd, 2007pk, 2010aj, 1995ad, and 1996W. Together with few other SNe they form a group of moderately luminous Type II events. We investigate the photometric similarities and differences among these bright objects. We also attempt to characterise them by analysing the spectral evolutions, in order to find some traces of CSM-ejecta interaction. Methods: We collected photometry and spectroscopy with several telescopes in order to construct well-sampled light curves and spectral evolutions from the photospheric to the nebular phases. Both photometry and spectroscopy indicate a degree of heterogeneity in this sample. Modelling the data of SNe 2009dd, 2010aj and 1995ad allows us to constrain the explosion parameters and the properties of the progenitor stars. Results: The light curves have luminous peak magnitudes (-16.95 < MB < -18.70). The ejected masses of 56Ni for three SNe span a wide range of values (2.8 × 10-2 M⊙ < M(56Ni)< 1.4 × 10-1 M⊙), while for a fourth (SN 2010aj) we could determine a stringent upper limit (7 × 10-3 M⊙). Clues of interaction, such as the presence of high velocity (HV) features of the Balmer lines, are visible in the photospheric spectra of SNe 2009dd and 1996W. For SN 2007pk we observe a spectral transition from a Type IIn to a standard Type II SN. Modelling the observations of SNe 2009dd, 2010aj and 1995ad with radiation hydrodynamics codes, we infer kinetic plus thermal energies of about 0.2-0.5 foe, initial radii of 2-5 × 1013 cm and ejected masses of ~5.0-9.5 M⊙. Conclusions: These

  10. OT2_mcordine_2: Revealing the nature of the remarkable object IRAS 19312+1950

    NASA Astrophysics Data System (ADS)

    Cordiner, M.

    2011-09-01

    The IRAS source 19312+1950 is a peculiar bipolar nebula that has eluded firm characterisation since its discovery. It exhibits maser and outflow properties similar to a massive O-rich AGB star, but shows molecular species such as CH3OH and HC3N that are more typically found in molecular clouds or YSOs. The source is surrounded by remarkable NIR nebulosity and has an unusual SED. The puzzle over the true nature of this object is confounded by our Spitzer IR spectrum that shows amorphous silicates and CO2 ice, but also emission from what may be crystalline silicates. In order to understand the physical properties of the gas and dust in the vicinity of IRAS 19312+1950, we propose to perform Herschel observations of emission from CO and H2O across a broad wavelength range from sub-mm to IR. Observations of transitions from a variety of energy levels will allow us to probe different temperature and density regimes within the source, from which we will construct a picture of its physical structure through radiative transfer/excitation modelling. HIFI observations will allow us to separate the broad and narrow molecular line components and PACS IFU mapping will provide crucial spatial information on the physical structure of the source. We also propose to perform a PACS SED scan to better characterise the source SED, and measure diagnostic spectral features of the dust and gas such as the forsterite 69 micron band, the OI 63 micron line and the N II 122 and 205 micron lines. The combination of these unique observations will help solve the puzzle of the nature of this peculiar object.

  11. Understanding Local Luminous Infrared Galaxies in the Herschel Era

    NASA Astrophysics Data System (ADS)

    Chu, Jason; Sanders, David B.; Larson, Kirsten L.; Mazzarella, Joseph M.; Howell, Justin; Diaz Santos, Tanio; Xu, C. Kevin; Paladini, Roberta; Schulz, Bernhard; Shupe, David L.; Appleton, Philip N.; Armus, Lee; Billot, Nicolas; Pan Chan, Hiu; Evans, Aaron S.; Fadda, Dario; Frayer, David T.; Haan, Sebastian; Mie Ishida, Catherine; Iwasawa, Kazushi; Kim, Dong-Chan; Lord, Steven D.; Murphy, Eric J.; Petric, Andreea; Privon, George C.; Surace, Jason A.; Treister, Ezequiel; Great Observatories All-Sky LIRG Survey, Cosmic Evolution Survey

    2017-06-01

    Luminous and ultraluminous infrared galaxies [(U)LIRGs] are some of the most extreme objects in the universe with their elevated star formation rates and/or presence of a powerful AGN, playing a central role in the evolution of galaxies throughout cosmic history. The 201 local (U)LIRGs (z<0.088) within the Great Observatories All-Sky LIRG Survey (GOALS) provide an unmatched opportunity to characterize the diverse properties in a large, statistically significant sample, in addition to comparisons with their high redshift counterparts. In this thesis talk I will first present the Herschel PACS and SPIRE far infrared image atlas of the entire GOALS sample (encompassing the 70-500 micron wavelength range), and demonstrate the excellent data quality. The Herschel GOALS images presented here are the highest resolution, most sensitive and comprehensive far-infrared imaging survey of the nearest (U)LIRGs to date. This allows us for the first time to directly probe the critical far infrared and submillimeter wavelength regime of these systems, enabling us to accurately determine the bolometric luminosities, infrared surface brightnesses, star formation rates, and dust masses and temperatures on spatial scales of 2-5 kpc. In addition, the superb resolution of Herschel means we can resolve many of the galaxy pairs and systems within the GOALS sample, allowing us to measure far infrared fluxes of component galaxies. Finally, using the Herschel photometry in conjunction with Spitzer, WISE, and IRAS data, I will show our first results on the global properties of (U)LIRGs such as their average 3-500 micron infrared SEDs and far infrared colors, and compare them to lower infrared luminosity objects. We will also compare and contrast their infrared SED shapes with previously published SED templates from the literature. If time permits, I will also show initial results from our rest-frame optical spectroscopy program on z~2.3 infrared selected galaxies in the COSMOS field.

  12. PROPERTIES AND KEPLERIAN ROTATION OF THE HOT CORE IRAS 20126+4104

    SciTech Connect

    Xu Jinlong; Wang Junjie; Ning Changchun

    2012-01-10

    We present Submillimeter Array (SMA) observations of the massive star-forming region IRAS 20126+4104 in the millimeter continuum and in several molecular line transitions. With the SMA data, we have detected nine molecular transitions, including deuterated hydrogen cyanide, CH{sub 3}OH, H{sub 2}CO, and HC{sub 3}N molecules, and imaged each molecular line. From the 1.3 mm continuum emission a compact millimeter source is revealed, which is also associated with H{sub 2}O, OH, and CH{sub 3}OH masers. Using a rotation temperature diagram, we derive that the rotational temperature and the column density of CH{sub 3}OH are 200 K and 3.7 Multiplication-Sign 10{sup 17} cm{sup -2}, respectively. The calculated results and analysis further indicate that a hot core coincides with IRAS 20126+4104. The position-velocity diagrams of H{sub 2}CO (3{sub 0,3}-2{sub 0,2}) and HC{sub 3}N (25-24) clearly present Keplerian rotation. Moreover, H{sub 2}CO (3{sub 0,3}-2{sub 0,2}) is found to trace the disk rotation for the first time.

  13. IRAS 03063+5735: A BOWSHOCK NEBULA POWERED BY AN EARLY B STAR

    SciTech Connect

    Kobulnicky, Henry A.; Lundquist, Michael J.; Bhattacharjee, Anirban; Kerton, C. R. E-mail: mlundqui@uwyo.edu E-mail: kerton@iastate.edu

    2012-03-15

    Mid-infrared images from the Spitzer Space Telescope Galactic Legacy Infrared MidPlane Survey Extraordinaire program reveal that the infrared source IRAS 03063+5735 is a bowshock nebula produced by an early B star, 2MASS 03101044+5747035. We present new optical spectra of this star, classify it as a B1.5 V, and determine a probable association with a molecular cloud complex at V{sub LSR} = -38 to -42 km s{sup -1} in the outer Galaxy near l = 140.{sup 0}59, b = -0.{sup 0}250. On the basis of spectroscopic parallax, we estimate a distance of 4.0 {+-} 1 kpc to both the bowshock nebula and the molecular complex. One plausible scenario is that this is a high-velocity runaway star impinging upon a molecular cloud. We identify the H II region and stellar cluster associated with IRAS 03064+5638 at a projected distance of 64 pc as one plausible birth site. The spectrophotometric distance and linkage to a molecular feature provides another piece of data helping to secure the ill-determined rotation curve in the outer Galaxy. As a by-product of spectral typing this star, we present empirical spectral diagnostic diagrams suitable for approximate spectral classification of O and B stars using He lines in the little-used yellow-red portion of the optical spectrum.

  14. An accretion disks in the high-mass star forming region IRA 23151+5912

    NASA Astrophysics Data System (ADS)

    Migenes, Victor; Rodríguez-Esnard, T.; Trinidad, M. A.

    2014-01-01

    We present observations of radio continuum emission at 1.3 and 3.6 cm and H2O masers toward the high-mass star-forming regions IRA 23151+5912 carried out with the VLA-EVLA. We detected one continuum source at 1.3 cm and 13 water maser spots which are distributed in three groups aligned along the northeast-southwest direction. Our results suggest that the 1.3 cm emission is consistent with an HC HII region, probably with an embedded zero-age main sequence star of type B2. In particular, we find that this radio continuum source is probably associated with a circumstellar disk of about 68 AU, as traced by water masers. Furthermore, the masers of the second group are probably describing another circumstellar disk of about 86 AU, whose central protostar is still undetected. We discuss this results in the light of more recent high-resolution observations.

  15. VizieR Online Data Catalog: YSO candidates in IRAS 20319+3958 (Djupvik+, 2017)

    NASA Astrophysics Data System (ADS)

    Djupvik, A. A.; Comeron, F.; Schneider, N.

    2016-11-01

    Table 3 contains positions and photometry in V, R, I, J, H, Ks, [3.6], [4.5], [5.8] and [8.0] of 144 YSO candidates around the globule IRAS 20319+3958. The VRI magnitudes and their errors are obtained with CAMELOT/IAC80 (Tenerife), the JHKs magnitudes and their errors are obtained with Omega2000/3.5m CAHA telescope (Calar Alto observatory), except for a few very bright and/or unresolved sources for which NOTCam/NOT (La Palma) is used. The IRAC/Spitzer magnitudes and errors are also given. The third last column gives a flag that shows either the YSO class or the YSO selection method. The naming used in the paper for the three brightest sources in the globule (A, B and C), of which two are binaries, are given in the second last column. The last column gives a photometry flag. (1 data file).

  16. Optical coherence tomography investigations of ceramic lumineers

    NASA Astrophysics Data System (ADS)

    Fernandes, Luana O.; Graça, Natalia D. R. L.; Melo, Luciana S. A.; Silva, Claudio H. V.; Gomes, Anderson S. L.

    2016-02-01

    Lumineers are veneer laminates used as an alternative for aesthetic dental solutions of the highest quality, but the only current means of its performance assessment is visual inspection. The objective of this study was to use the Optical Coherence Tomography (OCT) technique working in spectral domain to analyze in vivo in a single patient, 14 lumineers 180 days after cementation. It was possible to observe images in various kinds of changes in the cementing line and the laminate. It was concluded that the OCT is an effective and promising method to clinical evaluation of the cementing line in lumineers.

  17. OBSERVATIONAL STUDY OF THE CONTINUUM AND WATER MASER EMISSION IN THE IRAS 19217+1651 REGION

    SciTech Connect

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

    2012-12-20

    We report interferometric observations of the high-mass star-forming region IRAS 19217+1651. We observed the radio continuum (1.3 cm and 3.6 cm) and water maser emission using the Very Large Array (VLA-EVLA) in transition mode (configuration A). Two radio continuum sources were detected at both wavelengths, I19217-A and I19217-B. In addition, 17 maser spots were observed distributed mainly in two groups, M1 and M2, and one isolated maser. This latter could be indicating the relative position of another continuum source which we did not detect. The results indicate that I19217-A appears to be consistent with an ultracompact H II region associated with a zero-age main-sequence B0-type star. Furthermore, the 1.3 cm continuum emission of this source suggests a cometary morphology. In addition, I19217-B appears to be an H II region consisting of at least two stars, which may be contributing to its complex structure. It was also found that the H{sub 2}O masers of the group M1 are apparently associated with the continuum source I19217-A. These are tracing motions which are not gravitationally bound according to their spatial distribution and kinematics. They also seem to be describing outflows in the direction of the elongated cometary region. On the other hand, the second maser group, M2, could be tracing the base of a jet. Finally, infrared data from Spitzer, Midcourse Space Experiment, and IRIS show that IRAS 19217+1651 is embedded inside a large open bubble, like a broken ring, which possibly has affected the morphology of the cometary H II region observed at 1.3 cm.

  18. Generating luminous and dark matter during inflation

    NASA Astrophysics Data System (ADS)

    Barrie, Neil D.; Kobakhidze, Archil

    2017-05-01

    We propose a new mechanism for generating both luminous and dark matter during cosmic inflation. According to this mechanism, ordinary and dark matter carry common charge which is associated with an anomalous U(1)X group. Anomaly terms source 𝒞𝒫 and U(1)X charge violating processes during inflation, producing corresponding nonzero Chern-Simons numbers which are subsequently reprocessed into baryon and dark matter densities. The general framework developed is then applied to two possible extensions of the Standard Model with anomalous gauged B and B - L, each with an additional dark matter candidate. In each scenario, we consider the parameter choices that predict the correct dark matter to baryonic matter density ratio and baryon asymmetry. Interestingly, under these conditions, for the U(1)B-L extension we obtain a prediction for the mass of the dark matter candidate which is independent of the other choice of parameters, when assuming an ηB and ρDM/ρB.

  19. Infrared cirrus point sources

    NASA Technical Reports Server (NTRS)

    Reach, William T.; Heiles, Carl; Koo, Bon-Chul

    1989-01-01

    The IRAS discovered a large number of unresolved sources which were more intense at 100 microns than at shorter IR wavelengths. A sample of these point sources was isolated which are located in regions of very low Galactic H I column density. Whereas it was initially believed these sources to be prime candidates for a class of previously unknown astronomical object, the observations has proven that most of these sources are associated with the interstellar medium (ISM) of our Galaxy.

  20. Predicting a Luminous Red Nova

    NASA Astrophysics Data System (ADS)

    Van Noord, Daniel; Molnar, Larry; Kinemuchi, Karen; Steenwyk, Steven; Alexander, Cara; Spedden, Chris; Kobulnicky, Henry

    2016-05-01

    Luminous Red Novae (LRN) are rare transient events believed to be caused by the merger of a main sequence contact binary. Since the discovery of the prototype, V838 Mon, only a handful of LRN events have been observed. Tylenda et al. (2011) analyzed the OGLE data preceding the 2008 Novae of V1309 Sco and found that it exhibited a similar light curve to that of a contact binary with one interesting exception, the orbital period of V1309 Sco showed exponential period change going to zero. Unfortunately the system was discovered to be a binary after the merger, preventing any targeted observations to narrow down how the system entered this unusual state. However the extreme period change observed in V1309 Sco gives us a signature to look for in other contact binaries, allowing the discovery of merger candidates for follow up. We will present an analysis of light curves and spectra of KIC 9832227 (NSVS 5597755) that show it is a contact binary system with a negative period derivative that is becoming more extreme with time. These data span more than 15 years and are taken from the NSVS, ASAS, WASP, and Kepler surveys, with ongoing measurements from the Calvin College Observatory and the Apache Point Observatory. The ongoing period change observed in the system is consistent with the exponential model fit from V1309 Sco and the rate of period change has surpassed that of all other measured contact binaries with the exception of V1309 Sco. If the exponential period decay continues the system will likely merge between 2019 and 2022 resulting in a naked eye nova. If this event occurs, this star will present the unprecedented opportunity to study a LRN progenitor and to follow the evolution of the merger.

  1. IRAS galaxies versus POTENT mass - Density fields, biasing, and Omega

    NASA Technical Reports Server (NTRS)

    Dekel, Avishai; Bertschinger, Edmund; Yahil, Amos; Strauss, Michael A.; Davis, Marc; Huchra, John P.

    1993-01-01

    A comparison of the galaxy density field extracted from a complete redshift survey of IRAS galaxies brighter than 1.936 Jy with the mass-density field reconstructed by the POTENT procedure from the observed peculiar velocities of 493 objects is presented. A strong correlation is found between the galaxy and mass-density fields; both feature the Great Attractor, part of the Perseus-Pisces supercluster, and the large void between them. Monte Carlo noise simulations show that the data are consistent with the hypotheses that the smoothed fluctuations of galaxy and mass densities at each point are proportional to each other with the 'biasing' factor of IRAS galaxies, b(I), and that the peculiar velocity field is related to the mass-density field as expected according to the gravitational instability theory. Under these hypotheses, the two density fields can be related by specifying b(I) and the cosmological density parameter, Omega.

  2. Infrared Astronomical Satellite (IRAS) superfluid helium tank temperature control

    NASA Technical Reports Server (NTRS)

    Petrac, D.; Mason, P. V.

    1984-01-01

    The infrared detectors on the Infrared Astronomical Satellite (IRAS), which was placed into a polar orbit in January 1983, are cooled to a temperature of less than 3 K by thermal coupling to the main cryogenic tank (MCT) containing superfluid helium. A porous plug built into the vent line entrance acts as a superfluid helium liquid/vapor separator in zero gravity. A description of the IRAS MCT flight porous plug is presented, and tests of the plug in situ are discussed, taking into account submerged plug tests, a restart test, and a cold vapor flow test. Aspects of flow rate determination in the case of an unavailability of flight flow rate data are also considered.

  3. OH megamasers in high-luminosity IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Mirabel, I. F.; Sanders, D. B.

    1987-01-01

    OH megamaser emission and H I and CO profiles from the distant infrared galaxies IRAS 10173 + 0828, III Zw 035, and Zw 475.056 are reported. The OH isotropic luminosities at 1667 MHz are 463, 534, and 6.6 solar luminosities, respectively. Far-infrared pumping efficiencies of the OH greater than 1 percent are found in IRAS 10173 + 0828 and III Zw 035. These two galaxies show anomalously large 1667/1665 MHz emission line ratios. OH megamasers reside in the nuclei of superluminous far-infrared galaxies that have a high content of molecular gas, high efficiency of star formation, and in some instances, a striking deficiency of atomic hydrogen.

  4. OH megamasers in high-luminosity IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Mirabel, I. F.; Sanders, D. B.

    1987-01-01

    OH megamaser emission and H I and CO profiles from the distant infrared galaxies IRAS 10173 + 0828, III Zw 035, and Zw 475.056 are reported. The OH isotropic luminosities at 1667 MHz are 463, 534, and 6.6 solar luminosities, respectively. Far-infrared pumping efficiencies of the OH greater than 1 percent are found in IRAS 10173 + 0828 and III Zw 035. These two galaxies show anomalously large 1667/1665 MHz emission line ratios. OH megamasers reside in the nuclei of superluminous far-infrared galaxies that have a high content of molecular gas, high efficiency of star formation, and in some instances, a striking deficiency of atomic hydrogen.

  5. IRAS galaxies versus POTENT mass - Density fields, biasing, and Omega

    NASA Technical Reports Server (NTRS)

    Dekel, Avishai; Bertschinger, Edmund; Yahil, Amos; Strauss, Michael A.; Davis, Marc; Huchra, John P.

    1993-01-01

    A comparison of the galaxy density field extracted from a complete redshift survey of IRAS galaxies brighter than 1.936 Jy with the mass-density field reconstructed by the POTENT procedure from the observed peculiar velocities of 493 objects is presented. A strong correlation is found between the galaxy and mass-density fields; both feature the Great Attractor, part of the Perseus-Pisces supercluster, and the large void between them. Monte Carlo noise simulations show that the data are consistent with the hypotheses that the smoothed fluctuations of galaxy and mass densities at each point are proportional to each other with the 'biasing' factor of IRAS galaxies, b(I), and that the peculiar velocity field is related to the mass-density field as expected according to the gravitational instability theory. Under these hypotheses, the two density fields can be related by specifying b(I) and the cosmological density parameter, Omega.

  6. Eta Carinae and Other Luminous Blue Variables

    NASA Technical Reports Server (NTRS)

    Corcoran, M. F.

    2006-01-01

    Luminous Blue Variables (LBVs) are believed to be evolved, extremely massive stars close to the Eddington Limit and hence prone to bouts of large-scale, unstable mass loss. I discuss current understanding of the evolutionary state of these objects, the role duplicity may play and known physical characteristics of these stars using the X-ray luminous LBVs Eta Carinae and HD 5980 as test cases.

  7. A Bayesian classification of the IRAS LRS Atlas

    NASA Technical Reports Server (NTRS)

    Goebel, J.; Stutz, J.; Volk, K.; Walker, H.; Gerbault, F.; Self, M.; Taylor, W.; Cheeseman, P.

    1989-01-01

    The availability of a reclassification of the IRAS LRS Atlas of spectra using a new Bayesian classification procedure (AutoClass) is announced. The classes of objects which result from the application of the AutoClass algorithm include many of the previously known LRS classes. New classes which have interesting astronomical and astrophysical interpretations were also found. Techniques, such as the AutoClass algorithm, have a bright future in the arena of astronomical classification problems.

  8. Simultaneous chromatic and luminance human electroretinogram responses

    PubMed Central

    Parry, Neil R A; Murray, Ian J; Panorgias, Athanasios; McKeefry, Declan J; Lee, Barry B; Kremers, Jan

    2012-01-01

    The parallel processing of information forms an important organisational principle of the primate visual system. Here we describe experiments which use a novel chromatic–achromatic temporal compound stimulus to simultaneously identify colour and luminance specific signals in the human electroretinogram (ERG). Luminance and chromatic components are separated in the stimulus; the luminance modulation has twice the temporal frequency of the chromatic modulation. ERGs were recorded from four trichromatic and two dichromatic subjects (1 deuteranope and 1 protanope). At isoluminance, the fundamental (first harmonic) response was elicited by the chromatic component in the stimulus. The trichromatic ERGs possessed low-pass temporal tuning characteristics, reflecting the activity of parvocellular post-receptoral mechanisms. There was very little first harmonic response in the dichromats’ ERGs. The second harmonic response was elicited by the luminance modulation in the compound stimulus and showed, in all subjects, band-pass temporal tuning characteristic of magnocellular activity. Thus it is possible to concurrently elicit ERG responses from the human retina which reflect processing in both chromatic and luminance pathways. As well as providing a clear demonstration of the parallel nature of chromatic and luminance processing in the human retina, the differences that exist between ERGs from trichromatic and dichromatic subjects point to the existence of interactions between afferent post-receptoral pathways that are in operation from the earliest stages of visual processing. PMID:22586211

  9. Ratio model serves suprathreshold color- luminance discrimination

    NASA Astrophysics Data System (ADS)

    Sankeralli, Marcel J.; Mullen, Kathy T.; Hine, Trevor J.

    2002-03-01

    We extended earlier results [J. Opt. Soc. Am. A 16, 2625 (1999)] to examine how the responses of the three postreceptoral mechanisms are combined to subserve discrimination of suprathreshold stimuli. Test thresholds were obtained in the presence of suprathreshold pedestals selected in different quadrants of the red-green/luminance and blue-yellow/luminance planes of cardinal color space. We showed that (1) test threshold was directly proportional to pedestal contrast for pedestal contrasts exceeding five times pedestal contrast threshold, and (2) there were exceptions to this proportionality, notably when the test and pedestal directions were fixed in the cardinal directions. Results support a ratio model of suprathreshold color-luminance discrimination, in which discrimination depends on a ratio of outputs of the postreceptoral mechanisms. We also observed that when test threshold was measured as a function of test color-space direction, masking by the achromatic component of the pedestal was less than that by the chromatic component. In addition, masking by a dark (negative luminance component) pedestal was lower than masking by a light (positive luminance) pedestal of a similar contrast. Our results demonstrated that (1) there is no fundamental difference between discrimination in the isoluminant and in the two chromoluminant cardinal planes, (2) there exists the possibility that discrimination in cardinal directions differs from that in noncardinal (intermediate) directions, and (3) suprathreshold discrimination of luminance differences may be more sensitive than that of chromatic differences for a given suprathreshold pedestal.

  10. Study of Starburst/Activity/Interaction Phenomena based on the Multiple Byurakan-IRAS Galaxies

    NASA Astrophysics Data System (ADS)

    Harutyunyan, Gohar S.; Mickaelian, Areg M.

    2014-07-01

    The Byurakan-IRAS Galaxy (BIG) sample is the result of optical identifications of IRAS PSC sources at high-galactic latitudes using the First Byurakan Survey (FBS) low-dispersion spectra. Among the 1178 objects most are spiral galaxies and many have been proved to be AGN and starburst by spectroscopic observations, as well as there is a number of ULIRGs among these objects. BIG objects contain galaxy pairs, multiples, and small groups that are subject for study on the matter of the real IR-emitter in these systems. Given that these objects are powerful IR sources, they are considered as young systems indicating high rate of evolution and starburst activity exceeding 100 M o /yr. Spectroscopic observations show that all these systems are physical ones and we were able to measure the mutual distances and sizes for all components. Cross-correlations with the recent more accurate IR catalogues, such as 2MASS and WISE, as well as radio ones (NVSS, FIRST), provided accurate coordinates of the IR source and possibility to find the individual galaxy responsible for the IR. However, in almost half of the cases, IR position indicates the intermediate region between the components, which means that it comes from the system as a whole. Some more MW data have been matched to IR and radio to have an overall understanding on these systems. Given that these systems are mostly interacting/merging ones often containing AGN and most of them may be considered as powerful starbursts, it is possible to study starburst/activity/interaction phenomena and their interrelationship.

  11. High-velocity OH megamasers in IRAS 20100-4156: evidence for a supermassive black hole

    NASA Astrophysics Data System (ADS)

    Harvey-Smith, L.; Allison, J. R.; Green, J. A.; Bannister, K. W.; Chippendale, A.; Edwards, P. G.; Heywood, I.; Hotan, A. W.; Lenc, E.; Marvil, J.; McConnell, D.; Phillips, C. J.; Sault, R. J.; Serra, P.; Stevens, J.; Voronkov, M.; Whiting, M.

    2016-08-01

    We report the discovery of new, high-velocity narrow-line components of the OH megamaser in IRAS 20100-4156. Results from the Australian Square Kilometre Array Pathfinder (ASKAP)'s Boolardy Engineering Test Array (BETA) and the Australia Telescope Compact Array (ATCA) provide two independent measurements of the OH megamaser spectrum. We found evidence for OH megamaser clumps at -409 and -562 km s-1 (blue-shifted) from the systemic velocity of the galaxy, in addition to the lines previously known. The presence of such high velocities in the molecular emission from IRAS 20100-4156 could be explained by a ˜50 pc molecular ring enclosing a ˜3.8 billion solar mass black hole. We also discuss two alternatives, i.e. that the narrow-line masers are dynamically coupled to the wind driven by the active galactic nucleus or they are associated with two separate galactic nuclei. The comparison between the BETA and ATCA spectra provides another scientific verification of ASKAP's BETA. Our data, combined with previous measurements of the source enabled us to study the variability of the source over a 26 yr period. The flux density of the brightest OH maser components has reduced by more than a factor of 2 between 1988 and 2015, whereas a secondary narrow-line component has more than doubled in the same time. Plans for high-resolution very long baseline interferometry follow-up of this source are discussed, as are prospects for discovering new OH megamasers during the ASKAP early science programme.

  12. The Properties of IRAS Detected Mergers in the Local Universe

    NASA Astrophysics Data System (ADS)

    Carpineti, Alfredo; Kaviraj, S.; Clements, D. L.; Darg, D.; Hyde, A. K.; Lintott, C.

    2012-01-01

    Galaxy merging is a fundamental aspect of the standard hierarchical galaxy formation paradigm. We have used a large, homogeneous set of nearby mergers, selected through direct visual inspection of the entire SDSS using the GalaxyZoo project, to perform the first blind far-infrared (FIR) study of the local merger population. 3300+ mergers were cross-matched with the Imperial IRAS-FSC Redshift Catalogue, resulting in 606 FIR detections. The IRAS- detected mergers are typically more massive, with smaller separations, weaker tidal forces and bluer colours than their undetected counterparts. The IRAS-detected mergers are mostly (98%) spiral-spiral systems, with a median FIR luminosity of 1011 LSun and a median star-formation rate of around 15 MSun per year. They reside in low density environments but we find no dependence between group richness and their infrared properties. Their SFR seems to depend on the total mass of the system with little dependence on the mass ratio. Optical emission line ratios indicate that the AGN fraction increases with increasing FIR luminosity with a dramatic increase in the members that are ULIRGs . Comparing the typical separations of mergers that are LIRGs and those that are ULIRGs we estimate the timescale for this transition and find a value of (50 ± 16) Myr .

  13. IRAS far-infrared colours of normal stars

    NASA Technical Reports Server (NTRS)

    Waters, L. B. F. M.; Cote, J.; Aumann, H. H.

    1987-01-01

    The analysis of IRAS observations at 12, 25, 60 and 100 microns of bright stars of spectral type O to M is presented. The objective is to identify the 'normal' stellar population and to characterize it in terms of the relationships between (B-V) and (V-/12/), between (R-I) and (V-/12/), and as a function of spectral type and luminosity class. A well-defined relation is found between the color of normal stars in the visual (B-V), (R-I) and in the IR, which does not depend on luminosity class. Using the (B-V), (V-/12/) relation for normal stars, it is found that B and M type stars show a large fraction of deviating stars, mostly with IR excess that is probably caused by circumstellar material. A comparison of IRAS colors with the Johnson colors as a function of spectral type shows good agreement except for the K0 to M5 type stars. The results will be useful in identifying the deviating stars detected with IRAS.

  14. Absolute activity measurement of radon gas at IRA-METAS

    NASA Astrophysics Data System (ADS)

    Spring, Philippe; Nedjadi, Youcef; Bailat, Claude; Triscone, Gilles; Bochud, François

    2006-12-01

    This paper describes the system of the Swiss national metrological institute (IRA-METAS) for the absolute standardisation of radon gas. This method relies on condensing radon under vacuum conditions within a specified cold area using a cryogenerator, and detecting its alpha particles with an ion-implanted silicon detector, through a very accurately defined solid angle. The accuracy of this defined solid angle standardisation technique was corroborated by another primary measurement method involving 4 πγ NaI(Tl) integral counting and Monte Carlo efficiency calculations. The 222Rn standard submitted by IRA-METAS to the Système International de Référence (SIR) at the Bureau International des Poids et Mesures (BIPM) has also been found to be consistent with an analogous standard submitted by the German national metrological institute (PTB). IRA-METAS is able to deliver radon standards, with activities ranging from a few kBq to 350 kBq, in NIST-Type ampoules, and glass or steel containers usable for calibrating radon-measuring instruments.

  15. Characterization of halogen lamps as secondary standard of luminous flux

    NASA Astrophysics Data System (ADS)

    Marques, A. A. R.; Sanchez, O., Jr.; Ferreira, A. F. G., Jr.

    2011-09-01

    This work presents a study of lamps characterization concerning its lamp output, current and voltage drift during seasoning and regarding the use of theses lamps as luminous flux secondary standard. The 200W halogen lamps are seasoned for 30 hours and during the seasoning period the relative drift of the lamp illuminance, current and voltage are measured at each 3 minutes. The illuminance is measured using a photometer with detector head, the lamp voltage is measured using a 6.5 digits voltmeter and the current is measured using a 6.5 digits voltmeter and 0.1 Ohms standard resistor. The lamp current is controlled by a calibrated current power source with stability better than 1 mA. To reduce the stray light, baffles are positioned between the lamp and the detector head. The alignment of experimental assembly is made by a He-Ne Laser. Data of illuminance, current and voltage is acquired by software built in Labview database. Among the 5 lamps seasoned, the best result presents the variation of illuminance of 0.04% per hour. This lamp is chosen to become the secondary standard and its luminous flux is measured using an Ulbricht integrating sphere. This method allows the laboratory to create secondary standard of luminous flux for its routine test and measurements and to supply theses standards for Brazilian industry.

  16. Outgassing tests on iras solar panel samples

    NASA Technical Reports Server (NTRS)

    Premat, G.; Zwaal, A.; Pennings, N. H.

    1980-01-01

    Several outgassing tests were carried out on representative solar panel samples in order to determine the extent of contamination that could be expected from this source. The materials for the construction of the solar panels were selected as a result of contamination obtained in micro volatile condensable materials tests.

  17. 26 CFR 1.408A-3 - Contributions to Roth IRAs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Contributions to Roth IRAs. 1.408A-3 Section 1... (CONTINUED) INCOME TAXES Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.408A-3 Contributions to Roth... contributions to Roth IRAs: Q-1. What types of contributions are permitted to be made to a Roth IRA? A-1....

  18. Cosmological parameters from cluster abundances, cosmic microwave background and IRAS

    NASA Astrophysics Data System (ADS)

    Bridle, S. L.; Eke, V. R.; Lahav, O.; Lasenby, A. N.; Hobson, M. P.; Cole, S.; Frenk, C. S.; Henry, J. P.

    1999-12-01

    We combine information on cosmological parameters from cluster abundances, CMB primordial anisotropies and the IRAS 1.2-Jy galaxy redshift survey. We take as free parameters the present values of the total matter density of the universe, Ωm, the Hubble parameter, h, the linear theory rms fluctuations in the matter density within 8h-1Mpc spheres, σ8, and the IRAS biasing factor, bIRAS. We assume that the universe is spatially flat, with a cosmological constant, and that structure formed from adiabatic initial fluctuations with a Harrison-Zel'dovich power spectrum (i.e. the primordial spectral index n=1). The nucleosynthesis value for the baryonic matter density Ωb=0.019/h2 is adopted. We use the full three- and four-dimensional likelihood functions for each data set and marginalize these to two- and one-dimensional distributions in a Bayesian way, integrating over the other parameters. It is shown that the three data sets are in excellent agreement, with a best-fitting point of Ωm=1-ΩΛ=0.36, h=0.54, σ8=0.74, and bIRAS=1.08. This point is within one sigma of the minimum for each data set alone. Pairs of these data sets have their degeneracies in sufficiently different directions that using only two data sets at a time is sufficient to place good constraints on the cosmological parameters. We show that the results from each of the three possible pairings of the data are also in good agreement. Finally, we combine all three data sets to obtain marginalized 68per cent confidence intervals of 0.30<Ωm<0.43, 0.48IRAS<1.16. For the best-fitting parameters the CMB quadrupole is Qrms-ps=18.0μK, the shape parameter of the mass power spectrum is Γ=0.15, the baryon density is Ωb=0.066 and the age of the universe is 16.7Gyr.

  19. H-NS Regulation of IraD and IraM Antiadaptors for Control of RpoS Degradation

    PubMed Central

    Battesti, A.; Tsegaye, Y. M.; Packer, D. G.; Majdalani, N.

    2012-01-01

    RpoS, the master sigma factor during stationary phase and under a variety of stress conditions, is regulated at multiple levels, including regulated degradation. Degradation is dependent upon ClpXP and the RssB adaptor protein. H-NS, a nucleoid-associated protein, affects the regulated degradation of RpoS; in the absence of H-NS, RpoS is stable. The mechanisms involved in this regulation were not known. We have found that H-NS inhibits the expression of iraD and iraM, the genes coding for two antiadaptor proteins that stabilize RpoS when overexpressed. The regulation by H-NS of iraM is independent from the previously demonstrated regulation by the PhoP/PhoQ two-component system. Moreover, differences in the behavior of several hns alleles are explained by a role for StpA, an H-NS-like protein, in the regulation of RpoS stability. This finding parallels recent observations for a role of StpA in regulation of RpoS stability in Salmonella. PMID:22408168

  20. The Multiple Systems in the Young Stellar Cluster IRAS 05137+3919

    NASA Astrophysics Data System (ADS)

    Nikoghosyan, E. H.; Harutyunyan, H. A.; Azatyan, N. M.

    2016-09-01

    Four binary objects and one triplet have been revealed in the young stellar cluster located in the vicinity of IRAS 05137+3919 source on a distance 4.4 kpc with the use of statistic analysis. They are including the pair of Ae/Be Herbig stars. The percentage of the multiple systems in the cluster is mf = 5-6% and cp = 10-13%. The mass of the multiple systems' components are located in the range from ˜ 1 to 8 M⊙ and log P (rotation period in years) - from 4.4 to 4.7. The median value of the mass ratio of the components is q=0.86. The percentage of the multiple systems and their parameters in this cluster is resembling with the data obtained in the other star forming regions (ONC, Perseus, U Sco A), in which the values of mf and cp parameters are comparable with the results obtained for field's stellar population.

  1. El Perfil Sinusoidal del Jet HH 31 en la Protoestrella IRAS 042482612

    NASA Astrophysics Data System (ADS)

    Ferrero, L. V.; Gómez, M. N.

    In this contribution we study the HH 31 jet; associated with the Class I proto-star; IRAS 042482612 (age 10 yrs); in the Taurus molecular cloud. We use mid-infrared images; taken by Spitzer and WISE; to analyze the sinusoidal or S-shape chain of knots (or EGOs) that delineate the jet. The binarity of the central source naturally explains the wiggling jet. The orbital period is 2.7 times the estimated dynamical time of the jet. The spatial difference between knots agrees with time elapse expected between quasi-periodic FU Orionis events; suggesting that central star might have experimented this type of events several times since its birth. FULL TEXT IN SPANISH

  2. The carbon-rich proto-planetary nebula IRAS 22272 + 5435

    NASA Technical Reports Server (NTRS)

    Hrivnak, Bruce J.; Kwok, Sun

    1991-01-01

    Ground-based photometry and spectroscopy is presented for IRAS 22272 + 5435, a 9th mag star with a large infrared excess. The flux distribution is 'double-peaked', with a visible and near-infrared component due to the reddened photosphere and a far-infrared component presumably due to a detached dust shell. About equal amounts of energy are detected from each. The spectrum is that of a peculiar G supergiant, Gp Ia. In addition, strong molecular bands of C3 and C2 are observed. The flux distribution is modeled and, together with published molecular-line radio observations, allows the determination of basic parameters of the central star and the dust shell. The source has the characteristics one would expect of a proto-planetary nebula, an object in transition from the asymptotic giant branch to the planetary nebula phase.

  3. The carbon-rich proto-planetary nebula IRAS 22272 + 5435

    SciTech Connect

    Hrivnak, B.J.; Kwok, Sun Calgary, University )

    1991-04-01

    Ground-based photometry and spectroscopy is presented for IRAS 22272 + 5435, a 9th mag star with a large infrared excess. The flux distribution is 'double-peaked', with a visible and near-infrared component due to the reddened photosphere and a far-infrared component presumably due to a detached dust shell. About equal amounts of energy are detected from each. The spectrum is that of a peculiar G supergiant, Gp Ia. In addition, strong molecular bands of C3 and C2 are observed. The flux distribution is modeled and, together with published molecular-line radio observations, allows the determination of basic parameters of the central star and the dust shell. The source has the characteristics one would expect of a proto-planetary nebula, an object in transition from the asymptotic giant branch to the planetary nebula phase. 31 refs.

  4. The carbon-rich proto-planetary nebula IRAS 22272 + 5435

    NASA Astrophysics Data System (ADS)

    Hrivnak, Bruce J.; Kwok, Sun

    1991-04-01

    Ground-based photometry and spectroscopy is presented for IRAS 22272 + 5435, a 9th mag star with a large infrared excess. The flux distribution is 'double-peaked', with a visible and near-infrared component due to the reddened photosphere and a far-infrared component presumably due to a detached dust shell. About equal amounts of energy are detected from each. The spectrum is that of a peculiar G supergiant, Gp Ia. In addition, strong molecular bands of C3 and C2 are observed. The flux distribution is modeled and, together with published molecular-line radio observations, allows the determination of basic parameters of the central star and the dust shell. The source has the characteristics one would expect of a proto-planetary nebula, an object in transition from the asymptotic giant branch to the planetary nebula phase.

  5. Multi-Epoch Photometry of Luminous Stars in M31 and M33

    NASA Astrophysics Data System (ADS)

    Martin, John C.; Humphreys, Roberta M.

    2017-06-01

    Typically, the characteristics of supernovae and supernovae impostor progenitors are pieced together post-hoc from disparate sources after the event. Regular monitoring of luminous stars in nearby galaxies provides a more detailed and uniform source of information about those stars leading up to a significant event.We present Johnson/Cousins BVRI photometry from the first four years (2012 - 2016) of a targeted ground-based monitoring campaign of luminous stars in M31 and M33 including: likely supernovae and supernovae impostor progenitors, luminous infrared sources, classical LBVs, and warm and cool hypergiants. We have constructed a pipeline capable of quickly mining our images for photometry of additional targets.The survey will continue to image most of M31 and M33 on an annual basis for the foreseeable future.

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

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

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

  7. Reanalysis of the association of high-redshift 1-Jansky quasars with IRAS galaxies.

    NASA Astrophysics Data System (ADS)

    Bartsch, A.; Schneider, P.; Bartelmann, M.

    1997-03-01

    We develop a new statistical method to reanalyse angular correlations between background QSOs and foreground galaxies that are supposed to be a consequence of dark matter inhomogeneities acting as weak gravitational lenses. The method is based on a weighted average over the galaxy positions and is optimized to distinguish between a random distribution of galaxies around QSOs and a distribution which follows an assumed QSO-galaxy two-point correlation function, by choosing an appropriate weight function. With simulations we demonstrate that this weighted average is slightly more sensitive than Spearman's rank-order test which was used in previous investigations. In particular, the advantages of the weighted average show up if the correlation is weak. We then reanalyze the correlation between high-redshift 1-Jansky QSOs and IRAS galaxies taken from the IRAS Faint Source Catalog; these samples were analyzed previously using Spearman's rank-order test. In agreement with the previous work, we find moderate to strong correlations between these two samples; considering the angular two-point correlation function of these samples, we find a typical scale of order 5' from which most of the correlation signal derives. However, the statistical significance of the correlation changes with the redshift slices of the QSO sample one considers. Comparing with simple theoretical estimates of the expected correlation, we find that the signal we derive is considerably stronger than expected. On the other hand, recent direct verifications of the overdensity of matter in the line-of-sight to high-redshift radio QSOs obtained from the shear field around these sources indicate that the observed association can be attributed to a gravitational lens effect.

  8. SEARCH FOR CIRCUMSTELLAR DISKS AND RADIO JETS IN THE MASSIVE STAR-FORMATION REGION IRAS 23033+5951

    SciTech Connect

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

    2012-08-20

    We present radio continuum (1.3 and 3.6 cm) and H{sub 2}O maser observations toward the high-mass star-forming region IRAS 23033+5951 carried out with the VLA-EVLA (in transition phase) in the A configuration. Three radio continuum sources are detected at 3.6 cm, which are aligned in the east-west direction. However, no continuum emission is detected in the region at 1.3 cm. Based on the continuum information, we find that the two continuum sources detected in the region could be consistent with ultracompact H II regions harboring ZAMS B2 and B2.5 stars; however, we do not rule out that they could be associated with a radio jet. In addition, nine water maser spots are detected toward IRAS 23033+5951, which are clustered in two groups and located about 2'' to the south of the continuum sources. The spatio-kinematical distribution of the water masers suggests that they are tracing a circumstellar disk associated with a central star ZAMS B0, which could be the least evolved source in the region and has not developed an H II region yet. Moreover, as the circumstellar disk seems to be associated with the CO molecular outflow observed in the region, this conforms to a disk-YSO-outflow system, similar to that found in low-mass stars.

  9. Multi-epoch VLA observations of IRAS 16293-2422B and the modeling of its continuum emission

    NASA Astrophysics Data System (ADS)

    Hernández-Gómez, A.; Quénard, D.; Loinard, L.; Caux, E.

    2017-07-01

    We present multi-epoch interferometric observations of IRAS 16293-2422B taken with the Very Large Array at 0.7, 1, 1.3, 2, 3, 6 and 13 cm. We made continuum maps of the source at these wavelengths and measured a proper motion of -5.7±1.4 mas yr-1 in R.A. and -21.0±1.1 mas yr-1 in Dec. We also measured the spectral energy distribution for the source and found that the emission doesn't show any break in frequency as IRAS16293-2422A does, which is associated with free-free emission. We also observe that the size of this source increases always with the frequency, reaching a maximum of about 200 marcsec at 7 mm. This could indicate us that the emission is coming mostly from dust. We built up a model with a radiative transfer code (GASS-LIME) by considering the dust opacity, and the radial density and temperature profiles for the source. We show a comparison between our model and the continuum maps, proving that we are able to reproduce satisfactorily the continuum emission and the size for all the observations.

  10. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: Calibration and Targeted Sources

    NASA Astrophysics Data System (ADS)

    Truch, Matthew; BLAST Collaboration

    2007-12-01

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) operated successfully during a 100-hour flight from northern Sweden in June 2005 (BLAST05). As part of the calibration and pointing procedures, several compact sources were mapped, including solar system, Galactic, and extragalactic targets, specifically Pallas, CRL 2688, LDN 1014, IRAS 20126+4104, IRAS 21078+5211, IRAS 21307+5049, IRAS 22134+5834, IRAS 23011+6126, K3-50, W 75N, Mrk 231, NGC 4565, and Arp 220 (this last source being our primary calibrator). The BLAST observations of each compact source are described, flux densities and spectral energy distributions are reported, and these are compared with previous measurements at other wavelengths. BLAST was particularly useful for constraining the slope of the submillimeter continuum.

  11. Etendue-preserving mixing and projection optics for high-luminance LEDs, applied to automotive headlamps.

    PubMed

    Cvetkovic, Aleksandra; Dross, Oliver; Chaves, Julio; Benitez, Pablo; Miñano, Juan C; Mohedano, Rubén

    2006-12-25

    By having a single optical element combine the light of several high luminance LEDs, a high luminance light source can be formed, with shape and emission characteristics adaptable to nearly all illumination problems. The illuminance distribution of this virtual source facilitates the generation of the desired intensity pattern via its imaging-stye projection into the far field. This projection is achieved by one refractive and one reflective freeform surface, both calculated simultaneously by the 3D SMS method, which is herein demonstrated for an LED automotive headlamp.

  12. The Interstellar Bullet Engine IRAS05506+2414: A Molecular-Line Study

    NASA Astrophysics Data System (ADS)

    Sahai, Raghvendra; Patel, N.; Claussen, M. J.; Sanchez Contreras, C.; Morris, M. R.

    2012-01-01

    High-mass stars play a decisive role in the evolution of galaxies. An exciting recent development in the understanding of those early evolutionary stages, based on a new study of the Orion BN/KL region, is that the disruption of a massive young stellar system can lead to an explosive event producing a wide-angle outflow. This is an entirely different phenomenon from the classical bipolar flows driven by YSO accretion disks. We report here preliminary results from a molecular-line study of a serendipitously discovered object, IRAS05506+2414, which most likely is only the second known example of this phenomenon in our Galaxy. Our HST images show a fan-like spray of high-velocity (up to 350 km/s) elongated knots which appear to emanate from a bright compact central source. The physical properties (opening angle, outflow speeds, knot masses, Herbig-Haro-object like optical line emission) of the IRAS05506 wide-angle outflow are very similar to the one in Orion. A second jet engine, similar to those which drive the classical accretion-driven jets seen in low-mass YSOs, also appears to be operating simultaneously in IRAS05506. This is indicated by an optical jet-like feature aligned with a high-velocity (>100 km/s) molecular outflow which appears to be bipolar and nearly perpendicular to the average direction of the knot spray. Our molecular-line study includes (a) single-dish observations at 1.1-1.3 and 2.6-3 mm of high-density tracers such as HCO+, CS and SO, and mapping of the ambient molecular cloud in CO and 13CO using the ARO's 10- and 12-m dishes, and (b) interferometric observations at 2.6 and 1.3 mm with OVRO and the SMA of CO, 13CO, SO and SiO lines and the dust continuum. Preliminary results on the mass, density and temperature of the outflow and ambient cloud using simple excitation/radiative transfer models will be presented.

  13. Digital image comparison using feature extraction and luminance matching

    NASA Astrophysics Data System (ADS)

    Bachnak, Ray A.; Steidley, Carl W.; Funtanilla, Jeng

    2005-03-01

    This paper presents the results of comparing two digital images acquired using two different light sources. One of the sources is a 50-W metal halide lamp located in the compartment of an industrial borescope and the other is a 1 W LED placed at the tip of the insertion tube of the borescope. The two images are compared quantitatively and qualitatively using feature extraction and luminance matching approaches. Quantitative methods included the images' histograms, intensity profiles along a line segment, edges, and luminance measurement. Qualitative methods included image registration and linear conformal transformation with eight control points. This transformation is useful when shapes in the input image are unchanged, but the image is distorted by some combination of translation, rotation, and scaling. The gray-level histogram, edge detection, image profile and image registration do not offer conclusive results. The LED light source, however, produces good images for visual inspection by the operator. The paper presents the results and discusses the usefulness and shortcomings of various comparison methods.

  14. SUB-LUMINOUS {gamma}-RAY PULSARS

    SciTech Connect

    Romani, R. W.; Kerr, M.; Craig, H. A.; Johnston, S.; Cognard, I.; Smith, D. A.

    2011-09-01

    Most pulsars observed by the Fermi Large Area Telescope have {gamma}-ray luminosities scaling with spin-down power E-dot as L{sub {gamma}}{approx}(E-dot x 10{sup 33} erg s{sup -1}){sup 1/2}. However, there exist one detection and several upper limits an order of magnitude or more fainter than this trend. We describe these 'sub-luminous' {gamma}-ray pulsars and discuss the case for this being an orientation effect. Of the 12 known young radio pulsars with E-dot >10{sup 34} erg s{sup -1} and d {<=} 2 kpc several are substantially sub-luminous. The limited available geometrical constraints favor aligned geometries for these pulsars, although no one case for alignment is compelling. In this scenario GeV emission detected from such sub-luminous pulsars can be due to a lower altitude, lower-power accelerator gap.

  15. Sub-luminous γ-ray pulsars

    SciTech Connect

    Romani, R. W.; Kerr, M.; Craig, H. A.; Johnston, S.; Cognard, I.; Smith, D. A.

    2011-08-17

    Here, most pulsars observed by the Fermi Large Area Telescope have γ-ray luminosities scaling with spin-down power ${\\dot{E}}$ as $L_\\gamma \\approx ({\\dot{E}}\\, \\times \\, 10^{33}\\,{\\rm erg \\,s^{-1}})^{1/2}$. However, there exist one detection and several upper limits an order of magnitude or more fainter than this trend. We describe these "sub-luminous" γ-ray pulsars and discuss the case for this being an orientation effect. Of the 12 known young radio pulsars with ${\\dot{E}}>10^{34}\\, {\\rm erg\\,s^{-1}}$ and d ≤ 2 kpc several are substantially sub-luminous. The limited available geometrical constraints favor aligned geometries for these pulsars, although no one case for alignment is compelling. In this scenario GeV emission detected from such sub-luminous pulsars can be due to a lower altitude, lower-power accelerator gap.

  16. Mesopic luminance assessed with minimum motion photometry.

    PubMed

    Raphael, Sabine; MacLeod, Donald I A

    2011-08-25

    We measured the relative contribution of rods and cones to luminance across a range of photopic, mesopic, and scotopic adaptation levels and at various retinal eccentricities. We isolated the luminance channel by setting motion-based luminance nulls (minimum motion photometry) using annular stimuli. Luminance nulls between differently colored stimuli require equality in a weighted sum of rod and cone excitations. The relative cone weight increases smoothly from the scotopic range, where rods dominate, to photopic levels, where rod influence becomes negligible. The change from rod to cone vision does not occur uniformly over the visual field. The more peripheral the stimulus location, the higher is the light level required for cones to participate strongly. The relative cone contribution can be described by a sigmoid function of intensity, with two parameters that each depend on the eccentricity and spatial frequency of the stimulus. One parameter determines the "meso-mesopic" luminance--the center of the mesopic range, at which rod and cone contributions are balanced. This increases with eccentricity, reflecting an increase in the meso-mesopic luminance from 0.04 scotopic cd/m(2) at 2° eccentricity to 0.44 scotopic cd/m(2) at 18°. The second parameter represents the slope of the log-log threshold-versus-intensity curve (TVI curve) for rod vision. This parameter inversely scales the width of the mesopic range and increases only slightly with eccentricity (from 0.73 at 2° to 0.78 for vision at 18° off-axis).

  17. The cosmic X-ray background-IRAS galaxy correlation and the local X-ray volume emissivity

    NASA Technical Reports Server (NTRS)

    Miyaji, Takamitsu; Lahav, Ofer; Jahoda, Keith; Boldt, Elihu

    1994-01-01

    We have cross-correlated the galaxies from the IRAS 2 Jy redshift survey sample and the 0.7 Jy projected sample with the all-sky cosmic X-ray background (CXB) map obtained from the High Energy Astronomy Observatory (HEAO) 1 A-2 experiment. We have detected a significant correlation signal between surface density of IRAS galaxies and the X-ray background intensity, with W(sub xg) = (mean value of ((delta I)(delta N)))/(mean value of I)(mean value of N)) of several times 10(exp -3). While this correlation signal has a significant implication for the contribution of the local universe to the hard (E greater than 2 keV) X-ray background, its interpretation is model-dependent. We have developed a formulation to model the cross-correlation between CXB surface brightness and galaxy counts. This includes the effects of source clustering and the X-ray-far-infrared luminosity correlation. Using an X-ray flux-limited sample of active galactic nuclei (AGNs), which has IRAS 60 micrometer measurements, we have estimated the contribution of the AGN component to the observed CXB-IRAS galaxy count correlations in order to see whether there is an excess component, i.e., contribution from low X-ray luminosity sources. We have applied both the analytical approach and Monte Carlo simulations for the estimations. Our estimate of the local X-ray volume emissivity in the 2-10 keV band is rho(sub x) approximately = (4.3 +/- 1.2) x 10(exp 38) h(sub 50) ergs/s/cu Mpc, consistent with the value expected from the luminosity function of AGNs alone. This sets a limit to the local volume emissivity from lower luminosity sources (e.g., star-forming galaxies, low-ionization nuclear emission-line regions (LINERs)) to rho(sub x) less than or approximately = 2 x 10(exp 38) h(sub 50) ergs/s/cu Mpc.

  18. 26 CFR 1.408A-1 - Roth IRAs in general.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... by the Taxpayer Relief Act of 1997 (TRA 97), Public Law 105-34 (111 Stat. 788). (b) Roth IRAs are... Roth IRAs are not permitted to exceed $2,000 for a taxable year. Further, income earned on funds held...

  19. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 1: Explanatory supplement

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched on 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. Volume 1 describes the instrument, the mission, and data reduction.

  20. 26 CFR 1.408A-10 - Coordination between designated Roth accounts and Roth IRAs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Coordination between designated Roth accounts and Roth IRAs. 1.408A-10 Section 1.408A-10 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF... Plans, Etc. § 1.408A-10 Coordination between designated Roth accounts and Roth IRAs. Q-1. Can...