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Sample records for luminous iras source

  1. Evolution of luminous IRAS galaxies: Radio imaging

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Zhu, Lei; Wu, Yue-Fang

    2007-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Evans, A. S.

    1997-01-01

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

  6. Temperature distribution of dust in luminous IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Carico, David P.

    1989-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Leighly, Karen

    1999-01-01

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

  8. Extragalactic OH megamasers in strong IRAS sources

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  10. Unidentified IRAS sources: Ultrahigh luminosity galaxies

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  11. Extremely Luminous Far-infrared Sources (ELFS)

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  12. Radio properties of extragalactic IRAS sources

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  13. Ira.

    PubMed

    Petsko, Gregory A

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Unewisse, A. M.

    1992-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Hrivnak, Bruce J.; Kwok, S.

    1991-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1997-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  3. Constraining Emission Models of Luminous Blazar Sources

    SciTech Connect

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

    2009-10-30

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

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

    PubMed

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

    1989-06-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

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

    SciTech Connect

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

    2010-12-10

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

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

    SciTech Connect

    Jones, D. I.

    2015-02-01

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

  8. Compact radio sources in luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Parra, Rodrigo

    2007-08-01

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

  9. Ultra Luminous X-ray Sources

    NASA Astrophysics Data System (ADS)

    Webb, N. A.; Godet, O.

    2015-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Cohen, Martin; Jones, B. F.

    1987-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

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

    SciTech Connect

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

    2013-05-20

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

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

    SciTech Connect

    Imanishi, Masatoshi; Nakanishi, Kouichiro

    2013-10-01

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

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

    SciTech Connect

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

    1989-06-01

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

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

    PubMed

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

    2008-04-01

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

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

    SciTech Connect

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

    2009-05-20

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

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

    NASA Astrophysics Data System (ADS)

    Roman-Lopes, A.; Abraham, Z.

    2004-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2003-10-01

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

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

    NASA Astrophysics Data System (ADS)

    Roman-Lopes, A.

    2007-09-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

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

    SciTech Connect

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

    2011-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1992-02-01

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

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

    SciTech Connect

    Not Available

    1988-01-01

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

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

    NASA Technical Reports Server (NTRS)

    1988-01-01

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

  9. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 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.

  10. 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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Technical Reports Server (NTRS)

    Leighly, Karen M.

    1999-01-01

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

  13. The ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Smith, Harding E.

    1999-01-01

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

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

    NASA Astrophysics Data System (ADS)

    MacConnell, D. J.

    2010-08-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  16. 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.

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

    PubMed

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

    2008-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-10-01

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

  19. 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.

  20. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

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

    SciTech Connect

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

    2012-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Farooq, Tayyab; Qian, KeYuan

    2015-10-01

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

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

    SciTech Connect

    Not Available

    1988-01-01

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

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    Nikoghosyan, E. H.; Azatyan, N.

    2014-09-01

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

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

    NASA Technical Reports Server (NTRS)

    DiStefano, R.

    1996-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

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

    NASA 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. 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.

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

    SciTech Connect

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

    1990-07-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Yu, Hsueh-Ling; Liu, Wen-Chun

    2014-01-01

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

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

    SciTech Connect

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

    2013-05-01

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

  16. Infrared astronomy after IRAS

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  18. IRAS comet observations - The continuing saga

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  19. The IRAS Minor Planet Survey

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Karino, S.; Miller, J. C.

    2016-05-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    PubMed

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

    1988-02-01

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

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

    SciTech Connect

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

    2013-06-01

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

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

    SciTech Connect

    Gutiérrez, Carlos M.; Moon, Dae-Sik

    2014-12-10

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

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

    SciTech Connect

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

    2014-05-20

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

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

    SciTech Connect

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

    2011-04-20

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

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

    NASA Astrophysics Data System (ADS)

    Fukue, Jun

    2015-06-01

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

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

    SciTech Connect

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

    2014-04-10

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  14. The IRAS PSC/FSC Combined Catalogue

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    NASA Technical Reports Server (NTRS)

    Terebey, Susan; Surace, Jason A.

    1994-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Fukue, Jun; Umemura, Masayuki

    1995-08-01

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

  17. The IRAS view of the extragalactic sky

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    SciTech Connect

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

    2013-03-15

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-04-01

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

  2. IRAS software analysis library

    NASA Technical Reports Server (NTRS)

    Domik, Gitta; Merkle, C. Scott

    1991-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  4. The Most Luminous Galaxies Found by WISE

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  6. Models for infrared emission from IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Rowan-Robinson, M.

    1987-01-01

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

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

    SciTech Connect

    Cseh, D.; Corbel, S.

    2011-02-10

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

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

    SciTech Connect

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

    2009-09-10

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

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

    SciTech Connect

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

    2014-07-01

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

  11. Better Ira Remsen Demonstration

    ERIC Educational Resources Information Center

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

    2011-01-01

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

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

    SciTech Connect

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

    2012-12-20

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

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Mukai, Koji

    2014-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  17. Dust near luminous ultraviolet stars

    NASA Technical Reports Server (NTRS)

    Henry, Richard C.

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Anderson, Scott F.

    2003-01-01

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

  19. IRAS asteroid families

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

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

    SciTech Connect

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

    2013-08-15

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

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

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Masuda, Takao; Fukue, Jun

    2016-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Masuda, Takao; Fukue, Jun

    2016-04-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    SciTech Connect

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

    2011-04-01

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

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

    NASA Technical Reports Server (NTRS)

    Okajima, Takashi; Ebisawa, Ken; Kawaguchi, Toshihiro

    2007-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  11. IRAS observations of NGC 1052

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  12. IRAS observations of NGC 1052

    SciTech Connect

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

    1984-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

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

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod E.; Mushotzky, Richard F.

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  19. V1647 Orionis = IRAS 05436-0007

    NASA Astrophysics Data System (ADS)

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

    2004-06-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  1. Luminous presence

    NASA Astrophysics Data System (ADS)

    Dawson, Paula

    2008-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  4. IRAS observations of matter around nearby stars

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.

    1985-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1989-04-01

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

  7. Nuclear infrared emission and the colors of IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Hill, Gary J.

    1987-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    SciTech Connect

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

    1986-05-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Weaver, Wm. B.; Jones, Gordon

    1992-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  14. Water Masers Associated with IRAS 4A

    NASA Astrophysics Data System (ADS)

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

    2000-05-01

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

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

    NASA Technical Reports Server (NTRS)

    Smith, David A.; Wilson, Andrew S.

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Eisenhardt, P.

    2011-09-01

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

  17. Transcending boundaries with Ira Hirsh

    NASA Astrophysics Data System (ADS)

    Singh, Punita G.

    2002-05-01

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

  18. Dust near luminous ultraviolet stars

    NASA Technical Reports Server (NTRS)

    Henry, Richard C.

    1992-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Cohen, Martin

    1995-01-01

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

  2. Observations of Luminous Infrared Galaxies with Herschel

    NASA Astrophysics Data System (ADS)

    Armus, Lee

    2014-01-01

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

  3. Spatial deconvolution of IRAS galaxies at 60 UM

    NASA Technical Reports Server (NTRS)

    Low, Frank J.

    1987-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  5. Monsters and babies from the first / iras survey

    NASA Astrophysics Data System (ADS)

    van Breugel, Wil

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

  6. 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.

  7. 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

  8. 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

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  10. IRAS observations of irregular galaxies

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  11. 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.

  12. 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.

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

    SciTech Connect

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

    2010-11-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

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

    SciTech Connect

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

    1989-06-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Cohen, Martin

    1995-01-01

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

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  19. 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.

  20. Spatial analysis of IRAS observations of nearby spirals

    NASA Technical Reports Server (NTRS)

    Ball, Roger; Lo, R. Y.

    1990-01-01

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

  1. IRAS observations of active galaxies

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    The IRAS survey gives an unbiased view of the infrared properties of the active galaxies. Seyfert galaxies occupy much the same area in color-color plots as to normal infrared bright galaxies, but extend the range towards flatter 60 to 25 mm slopes. Statistically the Seyfert 1 galaxies can be distinguished from the Seyfert 2 galaxies, lying predominantly closer to the area with constant slopes between 25 and 200 mm. The infrared measurements of the Seyfert galaxies cannot distinguish between the emission mechanisms in these objects although they agree with the currently popular ideas; they do provide a measure of the total luminosity of the Seyferts. The quasar's position in the color-color diagrams continue the trend of the Seyferts. The quasar 3C48 is shown to be exceptional among the radio loud quasars in that it has a high infrared luminosity which dominates the power output of the quasar and is most likely associated with the underlying host galaxy.

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  3. EXOMARS IRAS (DOSE) radiation measurements.

    NASA Astrophysics Data System (ADS)

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

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

  4. A survey of IRAS data on 41 classical novae

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

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

    NASA 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.

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1999-12-01

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

  8. A young bipolar outflow from IRAS15398-3359

    NASA Astrophysics Data System (ADS)

    Bjerkeli, Per; Jørgensen, Jes K.

    2015-08-01

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

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

    NASA Astrophysics Data System (ADS)

    Sales, D.

    2015-09-01

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

  10. Critically evaluated/distributed database of IRAS LRS spectra

    NASA Technical Reports Server (NTRS)

    Stencel, R. E.

    1993-01-01

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

  11. Spatial studies of planetary nebulae with IRAS

    NASA Technical Reports Server (NTRS)

    Hawkins, G. W.; Zuckerman, B.

    1991-01-01

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

  12. Spatial studies of planetary nebulae with IRAS

    SciTech Connect

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

    1991-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Hui, Yawei

    2009-01-01

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

  14. Molecular jet of IRAS 04166+2706

    SciTech Connect

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

    2014-01-01

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

  15. Molecular Jet of IRAS 04166+2706

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

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

    SciTech Connect

    Chen, P. S.

    2012-10-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    SciTech Connect

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

    1990-06-19

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-01-01

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

  20. High spatial resolution restoration of IRAS images

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  1. What are IRAS galaxies? an optical answer

    NASA Astrophysics Data System (ADS)

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

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

  2. From IRAS Excesses to Debris Disks

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-10-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  5. THE TOTAL LUMINOUS EFFICIENCY OF LUMINOUS BACTERIA.

    PubMed

    Harvey, E N

    1925-09-18

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

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

    NASA Technical Reports Server (NTRS)

    Heckman, Timothy M.

    1999-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Bania, Thomas M.

    1992-01-01

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

  8. A redshift survey of IRAS galaxies

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    SciTech Connect

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

    2013-03-01

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

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

    SciTech Connect

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

    2015-01-20

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    SciTech Connect

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

    2009-12-10

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  14. Study of the Byurakan-IRAS galaxy sample

    NASA Astrophysics Data System (ADS)

    Mickaelian, Areg M.; Harutyunyan, Gohar S.

    2013-03-01

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

  15. Molecular gas associated with IRAS 10361-5830

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    SciTech Connect

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

    2015-01-01

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

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

    SciTech Connect

    Sametoglu, Ferhat

    2008-11-01

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

  19. Accretion disks in the IRAS 23151+5912 region

    SciTech Connect

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

    2014-06-20

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

  20. Erratum: IRAS observations of irregular galaxies

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  3. IRAS 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.

  4. 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).

  5. 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).

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

    NASA Astrophysics Data System (ADS)

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

    1998-12-01

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

  7. The Most Luminous Supernovae

    NASA Astrophysics Data System (ADS)

    Sukhbold, Tuguldur; Woosley, S. E.

    2016-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  16. Lidar Luminance Quantizer

    NASA Technical Reports Server (NTRS)

    Quilligan, Gerard; DeMonthier, Jeffrey; Suarez, George

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Evans, David L.

    1997-04-01

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

  3. WARM MOLECULAR GAS IN LUMINOUS INFRARED GALAXIES

    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.

  4. Warm Molecular Gas in Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  5. IRAS constraints on the sizes of Pluto and Charon

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  6. 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.

  7. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Nikoghosyan, E. H.; Azatyan, N.

    2014-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  11. Iras-Selected Galactic Star-Forming Regions - Part One - New 6/16-5/23 Water Maser Detections in Molecular Cores North of DEC +15DEG

    NASA Astrophysics Data System (ADS)

    Palumbo, G. G. C.; Scappini, F.; Pareschi, G.; Codella, C.; Caselli, P.; Attolini, M. R.

    1994-01-01

    The results are presented of a survey, performed with the Medicina 32-m parabolic reflector, of a sample of IRAS-selected sources associated with molecular clouds for water masers at 22 GHz (616 → 523). The final aim is to study the occurrence of maser emission from star-forming regions in the very early stages of evolution. The whole sample consists of 1409 IRAS sources selected by applying Emerson's colour criteria. In the present paper, results are given for sources with declinations greater than +15°, belonging to two subsamples that satisfy more restrictive colour criteria which should identify ultracompact H II regions (subsample A, 288 sources) and H II regions (subsample B, 133 sources). The main result of the present study is that 59 IRAS sources in the samples are water maser emitters, 11 of which are new detections from the present survey.

  12. 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.

  13. MEM application to IRAS CPC images

    NASA Technical Reports Server (NTRS)

    Marston, A. P.

    1994-01-01

    A method for applying the Maximum Entropy Method (MEM) to Chopped Photometric Channel (CPC) IRAS additional observations is illustrated. The original CPC data suffered from problems with repeatability which MEM is able to cope with by use of a noise image, produced from the results of separate data scans of objects. The process produces images of small areas of sky with circular Gaussian beams of approximately 30 in. full width half maximum resolution at 50 and 100 microns. Comparison is made to previous reconstructions made in the far-infrared as well as morphologies of objects at other wavelengths. Some projects with this dataset are discussed.

  14. 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.

  15. Independence of color and luminance edges in natural scenes.

    PubMed

    Hansen, Thorsten; Gegenfurtner, Karl R

    2009-01-01

    Form vision is traditionally regarded as processing primarily achromatic information. Previous investigations into the statistics of color and luminance in natural scenes have claimed that luminance and chromatic edges are not independent of each other and that any chromatic edge most likely occurs together with a luminance edge of similar strength. Here we computed the joint statistics of luminance and chromatic edges in over 700 calibrated color images from natural scenes. We found that isoluminant edges exist in natural scenes and were not rarer than pure luminance edges. Most edges combined luminance and chromatic information but to varying degrees such that luminance and chromatic edges were statistically independent of each other. Independence increased along successive stages of visual processing from cones via postreceptoral color-opponent channels to edges. The results show that chromatic edge contrast is an independent source of information that can be linearly combined with other cues for the proper segmentation of objects in natural and artificial vision systems. Color vision may have evolved in response to the natural scene statistics to gain access to this independent information. PMID:19152717

  16. The nuclear X-ray source in NGC 3628: A strange active galactic nucleus or the most luminous high-mass X-ray binary known?

    NASA Technical Reports Server (NTRS)

    Dahlem, Michael; Heckman, Timothy M.; Fabbiano, Giuseppina

    1995-01-01

    After 12 years, during which its unabsorbed soft X-ray flux in the 0.1-2.0 keV band was almost constant at about f(sub x) approximately 10(exp -12) ergs/s/sq cm, the compact nuclear source in NGC 3628 was not detected in one of our ROSAT observations, with a limiting sensitivity of f(sub x) approximately 5 x 10(exp -14) ergs/s/sq cm. Our data can be explained in two ways. The source is either the most massive X-ray binary known so far, with a greater than and approximately equal to 75 solar mass black hole, or an unusual low-luminosity Active Galactic Nuclei (AGN). The X-ray spectrum is typical of a high-mass X-ray binary, while the luminosity of the source of L(sub x) is approximately equal to 10(exp 40) ergs/s is more similar to those of low-luminosity AGNs. If it is an AGN, variable obscuration might explain the observed light curve.

  17. Radiation effects in IRAS extrinsic infrared detectors

    NASA Technical Reports Server (NTRS)

    Varnell, L.; Langford, D. E.

    1982-01-01

    During the calibration and testing of the Infrared Astronomy Satellite (IRAS) focal plane, it was observed that the extrinsic photoconductor detectors were affected by gamma radiation at dose levels of the order of one rad. Since the flight environment will subject the focal plane to dose levels of this order from protons in single pass through the South Atlantic Anomaly, an extensive program of radiation tests was carried out to measure the radiation effects and to devise a method to counteract these effects. The effects observed after irradiation are increased responsivity, noise, and rate of spiking of the detectors after gamma-ray doses of less than 0.1 rad. The detectors can be returned almost to pre-irradiation performance by increasing the detector bias to breakdown and allowing a large current to flow for several minutes. No adverse effects on the detectors have been observed from this bias boost, and this technique will be used for IRAS with frequent calibration to ensure the accuracy of observations made with the instrument.

  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. 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.

  20. A double detached shell around a post-red supergiant: IRAS 17163-3907, the Fried Egg nebula

    NASA Astrophysics Data System (ADS)

    Lagadec, E.; Zijlstra, A. A.; Oudmaijer, R. D.; Verhoelst, T.; Cox, N. L. J.; Szczerba, R.; Mékarnia, D.; van Winckel, H.

    2011-10-01

    Context. We performed a mid-infrared imaging survey of evolved stars to study the dust distribution in circumstellar envelopes around these objects and to understand the mass-loss mechanism responsible for the formation of these envelopes better. During this survey, we resolved the circumstellar environment of IRAS 17163-3907 for the first time (hereafter IRAS 17163), which is one of the brightest objects in the mid-infrared sky, but is surprisingly not well studied. Aims: Our aim is to determine the evolutionary status of IRAS 17163 and study its circumstellar environment to understand its mass-loss history. Methods: We obtained diffraction-limited images of IRAS 17163 in the mid-infrared using VISIR on the VLT. Optical spectra of the object allowed us to determine its spectral type and estimate its distance through diffuse interstellar bands. Results: We show that IRAS 17163 is a post-red supergiant, possibly belonging to the rare class of yellow hypergiants, and is very similar to the well-studied object IRC +10420. Our mid-infrared images of IRAS 17163 are the first direct images of this bright mid-infrared source. These images clearly show a double dusty detached shell around the central star, caused by successive ejections of material on a timescale of the order of 400 years and a total circumstellar mass exceeding than 4 M⊙. This indicates that non-quiescent mass-loss occurs during this phase of stellar evolution. Based on observations made with the Very Large Telescope at Paranal Observatory under program 081.D-0130(A).Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofsica de Canarias.

  1. 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.

  2. Personal glimpses of Ira Hirsh: Covariance of perception and reality

    NASA Astrophysics Data System (ADS)

    Clark, William

    2002-05-01

    No session honoring Ira Hirsh would be complete without a personal reflection of his enormous influence on his colleagues, students, and friends. During his career in St. Louis that covered the entire second half of the 20th Century (and still continues), Ira interacted with numerous colleagues at Central Institute for the Deaf, where he served as a senior scientist, Director of Research, and Institute Director. His second parallel career was at Washington University, where he was Professor of Psychology, and included a term as Dean of the Faculty of Arts and Sciences. This tribute will provide reflections and reminiscences of what it was like to work with, and learn from, Ira Hirsh.

  3. The IRAS view of the extragalactic sky

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.

    1986-01-01

    The global properties of the IR emissions from optically bright galaxies observed with the IRAS are described. A histogram of the morphological types of the galaxies is presented. Analysis of the ratio of far IR to blue luminosity (IR/B) reveals that the ratio covers a large range of about five orders of magnitude; 'normal galaxies' in the IR/B ratio of about 0.1-1.0 and galaxies with an IR/B ratio of greater than 1 are observed. The IR/B ratios for galaxies as a function of the 100 micron-60 micron flux density ratio are examined and it is detected that the galaxies which are more active in the IR display a warmer color temperature.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Cryogenic telescope on the Infrared Astronomical Satellite (IRAS)

    NASA Astrophysics Data System (ADS)

    Low, F. J.; Beichman, C. A.; Gillett, F. C.; Houck, J. R.; Neugebauer, G.; Langford, D. E.; Walker, R. G.; White, R. H.

    1984-04-01

    The Infrared Astronomical Satellite (IRAS) has completed an unbiased all-sky survey at wavelengths from 10 to 100 microns. The design and performance of the focal plane array is described with emphasis on in-orbit measurements of the sensitivity and stability. In the four broad spectral bands centered at 12, 25, 60, and 100 microns, the system noise equivalent flux density (NEFD) values are in Jy/(Square root of Hz), 0.03, 0.025, 0.046, and 0.21, respectively (Jansky = 10 to the -26th W/sq m/Hz). For point sources, a single scan at the survey rate of 3.8 arcmin/s yields limiting flux densities at the 3-sigma confidence level of 0.36, 0.30, 0.39, and 1.2 Jy. The dc stability of the junction field effect transistor (JFET) amplifiers and the excellent off-axis rejection of the telescope permit total flux measurements of extended infrared emission at levels below 6,000,000 Jy/sr. Response of the extrinsic silicon and germanium photo-detectors to ionizing radiation is described.

  14. Luminance meter for photopic and scotopic measurements in the mesopic range

    NASA Astrophysics Data System (ADS)

    Shpak, M.; Kärhä, P.; Porrovecchio, G.; Smid, M.; Ikonen, E.

    2014-09-01

    This paper presents a design and realization of a dual-channel luminance meter for simultaneous measurement of luminance with photopic and scotopic weightings. Such measurements are useful in mesopic conditions, i.e. when the luminance is in the range of 0.005-5 cd m-2. The instrument is a spot luminance meter with two spectrally weighted channels. The collected light is detected with silicon detectors and a computer-controlled dual-channel switched-integration amplifier. The instrument is characterized for relative spectral responsivity against a calibrated spectroradiometer using a radiance source based on an integrating sphere with input from a monochromator. An absolute luminance responsivity calibration is made against a sphere-based luminance standard at a level close to the high end of the mesopic range. The standard uncertainty in luminance responsivity calibration is 0.3% for the photopic channel and 0.6% for the scotopic channel. In addition, characterization measurements were carried out for the instrument’s linearity, stray light sensitivity and polarization dependence. The results show very good noise performance, allowing fast measurements over the whole mesopic range. The noise equivalent power was measured to be approximately 20 fW Hz-1/2, equal to a noise equivalent luminance of 30 µcd m-2 Hz-1/2. Estimated uncertainty of measurements for typical light sources is 2.2% (k = 2) at the lowest luminance levels of the mesopic range.

  15. The Luminosity-Metallicity relation of distant luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Liang, Y. C.; Hammer, F.; Flores, H.; Elbaz, D.; Marcillac, D.; Cesarsky, C. J.

    2004-09-01

    One hundred and five 15 \\mum-selected objects in three ISO (Infrared Space Observatory) deep survey fields (CFRS 3h, UDSR and UDSF) are studied on the basis of their high-quality optical spectra with resolution R>1000 from VLT/FORS2. ˜92 objects (88%) have secure redshifts, ranging from 0 to 1.16 with a median value of z_med=0.587. Considerable care is taken in estimating the extinction properties of individual galaxy, which can seriously affect diagnostic diagrams and estimates of star formation rates (SFRs) and of metal abundances. Two independent estimates of the extinction have been made, e.g. Balmer line ratio and energy balance between infrared (IR) and H\\beta luminosities. For most of the sources, we find a good agreement between the two extinction coefficients (within ±0.64 rms in AV, the extinction in V band), with median values of A_V(IR) = 2.36 and A_V(Balmer)= 1.82 for z>0.4 luminous IR galaxies (LIRGs). At z >0.4, our sample show many properties (IR luminosity, continuum color, ionization and extinction) strikingly in common with those of local (IRAS) LIRGs studied by Veilleux et al. (\\cite{Veilleux1995}). Thus, our sample can provide a good representation of LIRGs in the distant Universe. We confirm that most (>77%) ISO 15 μm-selected galaxies are dominated by star formation. Oxygen abundances in interstellar medium in the galaxies are estimated from the extinction-corrected ``strong'' emission line ratios (e.g. \\ion{[O}{ii]}/Hβ, \\ion{[O}{iii]}/Hβ and \\ion{[O}{iii]}/\\ion{[O}{ii]}). The derived 12+log(O/H) values range from 8.36 to 8.93 for the z>0.4 galaxies with a median value of 8.67. Distant LIRGs present a metal content less than half of that of the local bright disks (i.e. L*). Their properties can be reproduced with infall models although one has to limit the infall time to avoid overproduction of metals at late times. The models predict that total masses (gas + stars) of the distant LIRGs are from 1011 M⊙ to ≤1012 M⊙. A

  16. An Atlas of Warm Active Galactic Nuclei and Starbursts from the IRAS Deep Fields

    NASA Astrophysics Data System (ADS)

    Keel, William C.; Irby, Bryan K.; May, Alana; Miley, George K.; Golombek, Daniel; de Grijp, M. H. K.; Gallimore, Jack F.

    2005-06-01

    We present a set of 180 active galactic nucleus (AGN) candidates based on color selection from the IRAS slow-scan deep observations, with color criteria broadened from the initial Point Source Catalog samples so as to include similar objects with redshifts up to z=1 and allowing for two-band detections. Spectroscopic identifications have been obtained for 80 (44%); some additional identifications are secure based on radio detections or optical morphology, although yet unobserved spectroscopically. These spectroscopic identifications include 13 type 1 Seyfert galaxies, 17 type 2 Seyferts, 29 starburst galaxies, 7 LINER systems, and 13 emission-line galaxies so heavily reddened as to remain of ambiguous classification. The optical magnitudes range from R=12.0 to 20.5; the counts suggest that incompleteness is important fainter than R=15.5. Redshifts extend to z=0.51, with a significant part of the sample at z>0.2. Even with the relaxed color criteria, this sample includes slightly more AGNs than star-forming systems among those where the spectra contain enough diagnostic feature to make the distinction. The active nuclei include several broad-line objects with strong Fe II emission, and composite objects with the absorption-line signatures of fading starbursts. These AGNs with warm far-IR colors have little overlap with the ``red AGNs'' identified with 2MASS; only a single Seyfert 1 was detected by 2MASS with J-K>2. Some reliable IRAS detections have either very faint optical counterparts or only absorption-line galaxies, potentially being deeply obscured AGNs. The IRAS detections include a newly identified symbiotic star, and several possible examples of the ``Vega phenomenon,'' including dwarfs as cool as type K. Appendices detail these candidate stars, and the optical-identification content of a particularly deep set of high-latitude IRAS scans (probing the limits of optical identification from IRAS data alone). Based on observations from the European Southern

  17. Image reconstruction of IRAS survey scans

    NASA Technical Reports Server (NTRS)

    Bontekoe, Tj. Romke

    1990-01-01

    The IRAS survey data can be used successfully to produce images of extended objects. The major difficulties, viz. non-uniform sampling, different response functions for each detector, and varying signal-to-noise levels for each detector for each scan, were resolved. The results of three different image construction techniques are compared: co-addition, constrained least squares, and maximum entropy. The maximum entropy result is superior. An image of the galaxy M51 with an average spatial resolution of 45 arc seconds is presented, using 60 micron survey data. This exceeds the telescope diffraction limit of 1 minute of arc, at this wavelength. Data fusion is a proposed method for combining data from different instruments, with different spacial resolutions, at different wavelengths. Data estimates of the physical parameters, temperature, density and composition, can be made from the data without prior image (re-)construction. An increase in the accuracy of these parameters is expected as the result of this more systematic approach.

  18. 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.

  19. 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...

  20. 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....

  1. 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....

  2. 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....

  3. Organic Chemistry of Cha-MMS1 and IRAS 15194-5115 Probed by Microwave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Cordiner, M.; Charnley, S.

    2011-05-01

    We report new spectra of molecule-rich sources in the southern hemisphere obtained using the 22-metre 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.

  4. 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.

  5. VizieR Online Data Catalog: NRC 1333 IRAS 4A H2O observations (Santangelo+,

    NASA Astrophysics Data System (ADS)

    Santangelo, G.; Nisini, B.; Codella, C.; Lorenzani, A.; Yildiz, U. A.; Antoniucci, S.; Bjerkeli, P.; Cabrit, S.; Giannini, T.; Kristensen, L. E.; Liseau, R.; Mottram, J. C.; Tafalla, M.; van Dishoeck, E. F.

    2014-08-01

    We selected two active shock positions along the IRAS4A outflow: R1 (RA=03:29:10.82, DE=+31:13:51.9 (J2000)), at the origin of the jet from the driving source, and R2 (RA=03:29:14.59, DE=+31:14:45.8 (J2000)), which is the head of the red lobe of the outflow. They appear as very bright peaks in the PACS H2O (212-101) and CO (14-13) maps (4 data files).

  6. A search for massive young stellar objects with 98 CH3OH maser sources

    NASA Astrophysics Data System (ADS)

    Liu, Tie; Wu, Yue-Fang; Wang, Ke

    2010-01-01

    Using the 13.7 m telescope of the Purple Mountain Observatory (PMO), a survey of the J = 1-0 lines of CO and its isotopes was carried out on 98 methanol maser sources in January 2008. Eighty-five sources have infrared counterparts within one arcmin. In the survey, except for 43 sources showing complex or multiple-peak profiles, almost all the 13CO line profiles of the other 55 sources have large line widths of 4.5km s-1 on average and are usually asymmetric. Fifty corresponding Infrared Astronomical Satellite (IRAS) sources of these 55 sources have Lbol larger than 103 Lodot, which can be identified as possible high-mass young stellar sources. Statistics show that the 13CO line widths correlate with the bolometric luminosity of the associated IRAS sources. Here, we also report the mapping results of two sources: IRAS 06117+1350 and IRAS 07299-1651. Two cores were found in IRAS 06117+1350 and one core was detected in IRAS 07299-1651. The northwest core in IRAS 06117+1350 and the core in IRAS 07299-1651 can be identified as precursors of UC HII regions or high-mass protostellar objects (HMPOs). The southeast core of IRAS 06117+1350 has no infrared counterpart, seeming to be at a younger stage than the pre-UC HII phase.

  7. IRAS F13308+5946: A POSSIBLE TRANSITION PHASE FROM TYPE I ULTRALUMINOUS INFRARED GALAXY TO OPTICAL QUASAR

    SciTech Connect

    Meng Xianmin; Wu Hong; Wang Jing; Gu Qiusheng; Cao Chen

    2010-08-01

    We present a stellar population synthesis study of a type I luminous infrared galaxy: IRAS F13308+5946. It is a quasar with absolute magnitude M{sub i} = -22.56 and has the spectral feature of a Seyfert 1.5 galaxy. Optical images show characteristics of later stages of a merger. With the help of the stellar synthesis code STARLIGHT and both Calzetti et al.'s and Leitherer et al.'s extinction curves, we estimate the past infrared (IR) luminosities of the host galaxy and find that it may have experienced an ultraluminous infrared galaxy (ULIRG) phase for nearly 300 Myr, so this galaxy has probably experienced a type I ULIRG phase. Both nuclear starburst (SB) and active galactic nuclei contribute to the present IR luminosity budget, with the SB contributing {approx}70%. The mass of the supermassive black hole is M{sub BH} = 1.8 x 10{sup 8} M{sub sun} and the Eddington ratio L{sub bol}/L{sub Edd} is 0.12, both of which are approximate typical values of Palomar-Green QSOs. These results indicate that IRAS F13308+5946 is probably at the transitional phase from a type I ULIRG to a classical QSO.

  8. The curious case of the ultra fast wind in IRAS17020+4544: perspectives for the next decade

    NASA Astrophysics Data System (ADS)

    Longinotti, A.

    2016-06-01

    Outflowing winds from AGN may carry significant amount of mass and energy out to their host galaxies. I will present recent results on the newly discovered ultra fast outflow observed in the Seyfert 1 Galaxy IRAS17020+4544 by XMM-Newton. The exquisite data quality collected by the RGS instrument allowed us to detect a complex structure of the wind: for the first time, we could identify five components with different outflow velocities (in the range 0.08-0.11c) and distinct (moderate) ionization states. One of the outflow components may carry sufficient energy to substantially suppress star formation, and heat the gas in the host galaxy making IRAS17020+4544 a very interesting case for feedback by a moderately luminous Active Nucleus hosted in a spiral galaxy. This result comes after 15 years of XMM observations and it poses several open questions. Are moderate ionization X-ray ultra-fast winds so infrequent in AGN? What mechanism gives rise to the stratified structure of the wind? Is feedback from a spiral Galaxy truly unusual? How can we detect more winds of this type in the next decade? These and more questions will be reviewed and discussed in my presentation.

  9. 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.

  10. 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.

  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. 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.

  13. 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.

  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. 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.

  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. 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.

  18. Millimetric and Submillimetric Observations of IRAS 05327+3404 "Holoea" in M36

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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+ (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, ~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+ 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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. PMID:26816375

  9. 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.

  10. Modelling the extreme X-ray spectrum of IRAS 13224-3809

    NASA Astrophysics Data System (ADS)

    Chiang, Chia-Ying; Walton, D. J.; Fabian, A. C.; Wilkins, D. R.; Gallo, L. C.

    2015-01-01

    The extreme narrow-line Seyfert 1 galaxy IRAS 13224-3809 shows significant variability, frequency-dependent time lags, and strong Fe K line and Fe L features in the long 2011 XMM-Newton observation. In this work, we study the spectral properties of IRAS 13224-3809 in detail, and carry out a series of analyses to probe the nature of the source, focusing in particular on the spectral variability exhibited. The reflection grating spectrometer spectrum shows no obvious signatures of absorption by partially ionized material (`warm' absorbers). We fit the 0.3-10.0 keV spectra with a model that includes relativistic reflection from the inner accretion disc, a standard power-law active galactic nucleus continuum, and a low-temperature (˜0.1 keV) blackbody, which may originate in the accretion disc, either as direct or reprocessed thermal emission. We find that the reflection model explains the time-averaged spectrum well, and we also undertake flux-resolved and time-resolved spectral analyses, which provide evidence of gravitational light-bending effects. Additionally, the temperature and flux of the blackbody component are found to follow the L ∝ T4 relation expected for simple thermal blackbody emission from a constant emitting area, indicating a physical origin for this component.

  11. Distance and kinematics of IRAS 19134+2131 revealed by H2O maser observations

    NASA Astrophysics Data System (ADS)

    Imai, H.; Sahai, R.; Morris, M.

    2008-07-01

    Using the VLBA, we have observed H2O maser emission in the pre-planetary nebula, IRAS 19134+2131 (I1913), in which the H2O maser spectrum has two groups of emission features separated in radial velocity by ~100 km s-1. The morphology and 3-D kinematics indicate the existence of a fast collimated flow with a dynamical age of only ~40 years. Such a “water fountain” source is a signature of the recent operation of a stellar jet, that may be responsible for the final shape of the planetary nebula into which I1913 is expected to evolve. We have also estimated the distance to I1913 (~8 kpc) on the basis of an annual parallax and the kinematics of IRAS 19134+2131 in our Galaxy. I1913 may be a component in the “thick disk” or the Galactic “warp”, whose kinematics is different from that of the Galactic “thin” disk. These results are reported in Imai, Sahai & Morris (2007).

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

    SciTech Connect

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

    2011-06-10

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

  13. Byurakan-IRAS galaxies as massive galaxies with nuclear and starburst activity

    NASA Astrophysics Data System (ADS)

    Mickaelian, Areg M.; Harutyunyan, Gohar S.

    2013-07-01

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

  14. 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.

  15. 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.

  16. The complex environment around the low-mass protostar IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Schöier, Frederik L.; Jörgensen, Jes K.; Lahuis, Fred; van Dishoeck, Ewine F.; Blake, Geoff A.; Evans, Neal J.; C2d Irs Team

    The deeply embedded, low-mass, proto-binary star IRAS 16293-2422 has attained considerable interest over the last decade, in particular, driven by the detection of millimetre line emission from a large number of complex organic molecules and the possibility of this source harbouring a 'hot core', similar to those found in regions of high-mass star formation (e.g. van Dishoeck et al. 1995; Ceccarelli et al. 2000; Schöier et al. 2002; Cazaux et al. 2003). High angular resolution observations of the central core region of IRAS 16293-2422 have been carried out for a number of molecules using the BIMA and OVRO millimetre arrays (Schöier et al. 2005; see Figure 1 for examples). Most molecules show a separation of red (4-7 km s-1) and blue (0-4 km s-1) emission peaks roughly perpendicular to the large-scale outflow, thought to be driven by one of the protostars (MM1), indicative of rotation in the envelope. Some species, e.g. HNC and N2H+, also seem to trace the interaction of the outflow with the circumstellar material. The observed chemical differentiation of C18O, HNC, and N2H+ is consistent with the recent chemical model of IRAS 16293-2422 by Doty et al. (2004). Moreover, SiO and CH3OH appear to be partly associated with outflow activity where the ices are liberated by grain-grain collisions. We also report the detection of mid-infrared (23-35 μm) emission from IRAS 16293-2422 by the Spitzer Space Telescope infrared spectrograph, IRS (Jørgensen et al. 2005). The detection of mid-infrared emission suggests that the envelope is optically thin at these wavelengths. A detailed, spherically symmetric, radiative transfer model reproducing the full SED from 23 μm to 1.3mm requires a large, approximately 1000AU, inner cavity of the envelope in order to avoid quenching the emission from the central source (Figure 2). This corroborates a previous suggestion based on high angular resolution millimetre interferometric data (Schöier et al. 2004). An alternative

  17. Properties of unusually luminous supernovae

    NASA Astrophysics Data System (ADS)

    Pan, Tony Shih Arng

    This thesis is a theoretical study of the progenitors, event rates, and observational properties of unusually luminous supernova (SN), and aims to identify promising directions for future observations. In Chapter 2, we present model light curves and spectra of pair-instability supernovae (PISNe) over a range of progenitor masses and envelope structures for Pop III stars. We calculate the rates and detectability of PISNe, core-collapse supernovae (CCSNe), and Type Ia SNe at the Epoch of Reionization with the James Webb Space Telescope (JWST), which can be used to determine the contribution of Pop III versus Pop II stars toward ionizing the universe. Although CCSNe are the least intrinsically luminous supernovae, Chapter 5 shows that a JWST survey targeting known galaxy clusters with Einstein radii > 35" should discover gravitationally lensed CCSNe at redshifts exceeding z = 7--8. In Chapter 3, we explain the Pop II/I progenitors of observed PISNe in the local universe can be created via mergers in runaway collisions in young, dense star clusters, despite copious mass loss via line-driven winds. The PISN rate from this mechanism is consistent with the observed volumetric rate, and the Large Synoptic Survey Telescope could discover ~102 such PISNe per year. In Chapter 4, we identify 10 star clusters which may host PISN progenitors with masses up to 600 solar masses formed via runaway collisions. We estimate the probabilities of these very massive stars being in eclipsing binaries to be ≳ 30%, and find that their transits can be detected even under the contamination of the background cluster light, due to mean transit depths of ~10 6 solar luminosities. In Chapter 6, we show that there could be X-ray analogues of optically super-luminous SNe that are powered by the conversion of the kinetic energy of SN ejecta into radiation upon its collision with a dense but optically-thin circumstellar shell. We find shell configurations that can convert a large fraction of the SN

  18. IRAS Modulates Opioid Tolerance and Dependence by Regulating μ Opioid Receptor Trafficking.

    PubMed

    Li, Fei; Ma, Hao; Wu, Ning; Li, Jin

    2016-09-01

    Imidazoline receptor antisera-selected (IRAS) protein, the mouse homologue named Nischarin, was found to target to early endosomes with properties of sorting nexins in vitro. Recently, we generated IRAS knockout mice and found IRAS deficiency exacerbated the analgesic tolerance and physical dependence caused by opioids, suggesting that IRAS plays a role in regulating μ opioid receptor (MOR) functions. In the present study, we found that IRAS interacts with MOR and regulates MOR trafficking in vitro. In the CHO or HEK293 cells co-expressing MOR and IRAS, IRAS, through its PX domain, interacted with MOR. The interaction facilitated the recycling of internalized MOR and prevented MOR downregulation induced by DAMGO, the MOR agonist. Functionally, IRAS accelerated MOR resensitization and attenuated DAMGO-induced MOR desensitization, which is believed as one of mechanisms mediating opioid tolerance and dependence. Taken together, we propose that IRAS is a new MOR interacting protein and regulates agonist-induced trafficking of MOR via sorting internalized MOR to the recycling pathway, which may be a molecular mechanism underlying IRAS modulating opioid tolerance and dependence. PMID:26363797

  19. Infrared atomic hydrogen line formation in luminous stars

    NASA Technical Reports Server (NTRS)

    Krolik, J. H.; Smith, H. A.

    1981-01-01

    Infrared atomic hydrogen lines observed in luminous stars, generally attributed to compact circumstellar H II regions, can also be formed in the winds likely to emanate from these stars. Implications are discussed for the class of obscured infrared point sources showing these lines, and an illustrative model is derived for the BN object in Orion. Such stellar winds should also produce weak, but detectable, radio emission.

  20. IRAS observations of optically selected galaxies. I - The properties of the UGC redshift sample

    NASA Technical Reports Server (NTRS)

    Bothun, Gregory D.; Lonsdale, Carol J.; Rice, Walter

    1989-01-01

    The FIR properties of more than 2400 optically selected galaxies in the Uppsala General Catalog are examined. The galaxies were detected by IRAS at 60 and 100 microns and have measured redshifts. A simple radiative transfer model is presented to study the nature of dust-heating sources. It is shown that for many normal disk galaxies, dust heated by old disk stars competes with dust heated by UV photons from newly formed stars. It is found that the 60-micron/100-micron flux density ratio may be used as an indicator of the dominant dust-heating source. Scaling relations with galaxy size and mass are presented which make it possible to estimate the contributions of any cirrus-like component to the total FIR luminosity.

  1. 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

  2. Night sky luminance under clear sky conditions: Theory vs. experiment

    NASA Astrophysics Data System (ADS)

    Kocifaj, Miroslav

    2014-05-01

    Sky glow is caused by both natural phenomena and factors of anthropogenic origin, and of the latter ground-based light sources are the most important contributors for they emit the spatially linked spectral radiant intensity distribution of artificial light sources, which are further modulated by local atmospheric optics and perceived as the diffuse light of a night sky. In other words, sky glow is closely related to a city's shape and pattern of luminaire distribution, in practical effect an almost arbitrary deployment of random orientation of heterogeneous electrical light sources. Thus the luminance gradation function measured in a suburban zone or near the edges of a city is linked to the City Pattern or vice versa. It is shown that clear sky luminance/radiance data recorded in an urban area can be used to retrieve the bulk luminous/radiant intensity distribution if some a-priori information on atmospheric aerosols is available. For instance, the single scattering albedo of aerosol particles is required under low turbidity conditions, as demonstrated on a targeted experiment in the city of Frýdek-Mistek. One of the main advantages of the retrieval method presented in this paper is that the single scattering approximation is satisfactorily accurate in characterizing the light field near the ground because the dominant contribution to the sky glow has originated from beams propagated along short optical paths.

  3. 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.

  4. Luminous efficiency functions at higher intensities

    NASA Astrophysics Data System (ADS)

    Harrington, Lawrence Kent

    Two psychophysical measurement techniques, flicker photometry and successive heterochromatic brightness matching, were used to measure changes in luminance efficiency functions with increasing levels of light adaptation. Both measurement techniques were performed using the same optical system and the same seven healthy adults as subjects. Measurements were taken at four reference stimulus intensities, 1, 10, 100 and 1000 foot-lamberts. Luminous efficiency was found to depend on both the technique and the reference stimulus intensity with which the measurements were taken. For heterochromatic brightness matching, luminous efficiency increased for longer wavelengths as reference intensity increased. Peak luminous efficiency shifted from approximately 540nm to greater than 600nm with increasing intensity for all seven subjects. Peak luminous efficiency was constant for flicker photometry across all intensities but the function narrowed slightly at 100 foot-lamberts.

  5. 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

  6. A young bipolar outflow from IRAS 15398-3359

    NASA Astrophysics Data System (ADS)

    Bjerkeli, P.; Jørgensen, J. K.; Brinch, C.

    2016-03-01

    Context. Changing physical conditions in the vicinity of protostars allow for a rich and interesting chemistry to occur. Heating and cooling of the gas allows molecules to be released from and frozen out on dust grains. These changes in physics, traced by chemistry as well as the kinematical information, allows us to distinguish between different scenarios describing the infall of matter and the launching of molecular outflows and jets. Aims: We aim to determine the spatial distribution of different species that are of different chemical origin. This is to examine the physical processes in play in the observed region. From the kinematical information of the emission lines we aim to determine the nature of the infalling and outflowing gas in the system. We also aim to determine the physical properties of the outflow. Methods: Maps from the Submillimeter Array (SMA) reveal the spatial distribution of the gaseous emission towards IRAS 15398-3359. The line radiative transfer code LIME is used to construct a full 3D model of the system taking all relevant components and scales into account. Results: CO, HCO+, and N2H+ are detected and shown to trace the motions of the outflow. For CO, the circumstellar envelope and the surrounding cloud also have a profound impact on the observed line profiles. N2H+ is detected in the outflow, but is suppressed towards the central region, perhaps because of the competing reaction between CO and H3+ in the densest regions as well as the destruction of N2H+ by CO. N2D+ is detected in a ridge south-west of the protostellar condensation and is not associated with the outflow. The morphology and kinematics of the CO emission suggests that the source is younger than ~1000 years. The mass, momentum, momentum rate, mechanical luminosity, kinetic energy, and mass-loss rate are also all estimated to be low. A full 3D radiative transfer model of the system can explain all the kinematical and morphological features in the system.

  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. 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.

  9. SIO Emission in the Multilobe Outflow Associated with IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Hirano, Naomi; Mikami, Hitomi; Umemoto, Tomofumi; Yamamoto, Satoshi; Taniguchi, Yoshiaki

    2001-02-01

    We have mapped the thermal emission line of SiO (v=0; J=2-1) associated with the quadrupolar molecular outflow driven by the very cold far-infrared source IRAS 16293-2422. The SiO emission is significantly enhanced in the northeastern red lobe and at the position ~50" east of the IRAS source. Strong SiO emission observed at ~50" east of the IRAS source presents evidence for a dynamical interaction between a part of the eastern blue lobe and the dense ambient gas condensation; however, such an interaction is unlikely to be responsible for producing the quadrupolar morphology. The SiO emission in the northeastern red lobe shows spatial and velocity structure similar to those of the CO outflow, suggesting that the SiO emission comes from the molecular outflow in the northeastern red lobe itself. The observed velocity structure is reproduced by a simple spatiokinematic model of bow shock with a shock velocity of 19-24 km s-1 inclined by 30°-45° from the plane of the sky. This implies that the northeastern red lobe is independent of the eastern blue lobe and that the quadrupolar structure is due to two separate bipolar outflows. The SiO emission observed in the western red lobe has a broad pedestal shape with low intensity. Unlike the SiO emission in the northeastern red lobe, the spatial extent of the SiO emission in the western red lobe is restricted to its central region. The spatial and velocity structures and the line profiles suggest that three different types of SiO emission are observed in this outflow: the SiO emission arising from the interface between the outflowing gas and the dense ambient gas clump, the SiO emission coming from the outflow lobe itself, and the broad SiO emission with low intensity observed at the central region of the outflow lobe. Based on observations made at the Nobeyama Radio Observatory (NRO). Nobeyama Radio Observatory is a branch of the National Astronomical Observatory of Japan, an interuniversity research institute operated by

  10. Origin of the solar system dust bands discovered by IRAS

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.; Nicholson, P. D.; Burns, J. A.; Houck, J. R.

    1984-01-01

    It is shown that distinctive longitudinal variations in thermal flux and mean latitude can be used to determine the typical orbits of the grains comprising the Solar System bands. In particular, how the bands should vary if they are debris associated with the three principal asteroid families is predicted. Based on these ideas, IRAS observations may allow discrimination between asteroidal and cometary origins of the dust bands and, perhaps, of the entire zodiacal cloud.

  11. A reinterpretation of millimeter observations of nearby IRAS excess stars

    NASA Technical Reports Server (NTRS)

    Weintraub, David A.; Stern, S. Alan

    1994-01-01

    We analyze new and previously published 1300, 870, and 800 micrometers, single-element bolometer observations of Vega (alpha Lyr), Formalhaut (alpha PsA), epsilon Eri, tau(sup1) Eri, and Beta Leo. We show that these data are consistent with models in which the dust disks around these stars are larger than the radio telescope beams with which they were observed; thus, these disks may be many hundreds of AU in radius or larger. Our interpretation of submillimeter/millimeter measurements of these stars also indicates that for some Infrared Astronomy Satellite (IRAS) IR excess stars the assumption that there is no astrophysical flux in the OFF beams, when using the standard ON-minus-OFF chopping technique and the chop distance is less than 1000AU, may be incorrect. Therefore, for IRAS IR excess stars within approximately 20 pc, virtually all submillimeter/millimeter chopping observations with chop throws less than 100" may have subtracted away some or most of the flux associated with their circumstellar disks. Finally, we present new 1300 micrometers continuum observations of Vega made with chop throws of 500 and 1000 AU. These data are consistent with an interpretation in which Vega has a disk that is at least 1000AU in radius; this disk could have a region with much less material per beam area near 500 AU than at both 100 AU and 1000 AU, corresponding to a gap at the orbital distance of alpha Lyr B. The observations of Vega are also consistent with the assumption that the circumVega dust structure is unresolved. Thus, these new data very effectively illustrate that the 'standard' model of small, unresolved, dust structures around main-sequence IRAS IR excess stars is not unique. Maps of IRAS IR excess stars, which soon will be available from submillimeter/millimeter array detectors, will determine whether the paradigm shift we propose will occur.

  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. The IR properties of ringed galaxies and the IRAS database

    NASA Technical Reports Server (NTRS)

    Buta, Ronald J.; Crocker, Deborah A.

    1993-01-01

    Our study of the Infrared Astronomy Satellite (IRAS) properties of ringed galaxies has been largely successful. We have identified what we think is the probable cause of the differences in the IRAS properties among non-interacting barred galaxies as the pattern speed of the bar. The key to identifying this parameter has been our focusing the study on outer-ringed galaxies where we know precisely what is present in the central regions (from available BVI CCD images in our library of images). The theory is that outer rings, through their morphology and other characteristics, can be identified with the outer Lindblad resonance, one of the major resonances in galaxy structure. Using a library of n-body simulations for comparison, we can reliably infer both low and high pattern speed galaxies from the appearance of outer rings and the existence of other ring features. It is clear that in some barred galaxies, the bar pattern speed is high enough to avoid an inner Lindblad resonance, hence such objects do not contain nuclear or circumnuclear star formation. The IRAS observations are most sensitive to nuclear star formation in early-type barred galaxies, and will thus select those barred galaxies where the pattern speed is low enough to allow an inner Lindblad resonance to exist. High pattern speed barred galaxies therefore weaken the correlation between bars and infrared excess. This finding helps to reconcile the inconsistent results found between different studies on the correlation between bars and far-IR emission.

  14. 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

  15. A HOT MOLECULAR OUTFLOW DRIVEN BY THE IONIZED JET ASSOCIATED WITH IRAS 16562-3959

    SciTech Connect

    Guzman, Andres E.; Garay, Guido; Rathborne, Jill; Brooks, Kate J.; Guesten, Rolf

    2011-08-01

    We report molecular line observations in the CO J = 3 {yields} 2, 6 {yields} 5, and 7 {yields} 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{sub sun}, a total momentum of {approx}89 M{sub sun} km s{sup -1}, and an averaged momentum rate of {approx}3.0 x 10{sup -2} M{sub sun} km s{sup -1} yr{sup -1}, values characteristic of flows driven by young massive stellar objects with high luminosities (L{sub bol} {approx} 2 x 10{sup 4} L{sub 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.

  16. 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. P.; Sault, R. J.; Serra, P.; Stevens, J.; Voronkov, M.; Whiting, M.

    2016-05-01

    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 twenty-six year period. The flux density of the brightest OH maser components has reduced by more than a factor of two between 1988 and 2015, whereas a secondary narrow-line component has more than doubled in the same time. Plans for high-resolution VLBI follow-up of this source are discussed, as are prospects for discovering new OH megamasers during the ASKAP early science program.

  17. 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.

  18. 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.

  19. 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.

  20. Spectroscopic Study of HD 179821 (IRAS 19114+0002): Proto-Planetary Nebula or Supergiant?

    NASA Technical Reports Server (NTRS)

    Reddy, B. E.; Hrivnak, Bruce J.

    1999-01-01

    A detailed chemical composition analysis of the bright post-AGB candidate HD 179821 (IRAS 19114 + 0002) is presented. The LTE analysis, based on high-resolution (R approximately equal 50,000) and high-quality (S/N approximately equal 300) spectra, yields atmospheric parameters T(sub eff) = 6750 K, log g = 0.5, and xi(sub t) = 5.25 km/s. The elemental abundance results of HD 179821 are found to be [Fe/H] = -0.1, [C/Fe] = +0.2, [N/Fe] = +1.3, [O/Fe] = +0.2, [alpha-process/Fe] = +0.5, and [s-process/Fe] = +0.4. These values clearly differ from the elemental abundances of Population I F supergiants. The C, N, and O abundances and the total CNO abundance value relative to Fe, [C+N+O/Fe] = +0.5, indicate that the photosphere of HD 179821 is contaminated with both the H- and He-burning products of the AGB phase. The evidence for He burning through the 3.alpha process and deep AGB mixing also comes from the observed overabundances of s-process elements. Remarkably, the abundance of the element Na is found to be very large, [Na/Fe] = +0.9. The ratio O/C = 2.6 indicates that the atmosphere is oxygen rich. The results of this abundance study support the argument that HD 179821 is a proto-planetary nebula,. probably with an intermediate-mass progenitor. However, the strength of the O I triplet lines at 7774 A and the distance derived from the interstellar Na I D1 and D2 components imply that the star is a luminous object (M(sub bol) approximately -8.9 +/- 1) and thus a massive supergiant. Thus, while this study contributes important new observational results for this star, an unambiguous determination of its evolutionary status has yet to be achieved.

  1. Planning and Measuring Luminance Contrast in Staircases.

    PubMed

    Houck, Leif D; Gundersen, Kristoffer; Strengen, Ola

    2016-01-01

    Norwegian legislation has requirements concerning luminance contrast for different elements in staircases. This paper investigates how architects work to meet the requirements, how to measure the actual built luminance contrasts and finally 21 staircases are measured using two different methods. The results show that some architects do not reflect on luminance contrasts at all, some use their "experience" and some try to measure the reflectance value of different materials during planning. The investigations also reveal that there is not any official predefined way to control luminance contrast, and this investigation shows that different approaches will give different results. To perform the measuring of the built staircases, it has been necessary to develop a defined measuring method. The results of the measuring generally shows that only a few of the staircases studied fully meet the legislation requirements. PMID:27534331

  2. 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.

  3. 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.

  4. MIDCOURSE SPACE EXPERIMENT VERSUS IRAS TWO-COLOR DIAGRAMS AND THE CIRCUMSTELLAR ENVELOPE-SEQUENCE OF OXYGEN-RICH LATE-TYPE STARS

    SciTech Connect

    Sjouwerman, Lorant O.; Capen, Stephanie M.; Claussen, Mark J. E-mail: stephanie.m.capen@enc.ed

    2009-11-10

    We present Midcourse Space Experiment (MSX) two-color diagrams that can be used to characterize circumstellar environments of sources with good quality MSX colors in terms of IRAS color regions for oxygen-rich stars. With these diagrams, we aim to provide a new tool that can be used to study circumstellar environments and to improve detection rates for targeted surveys for circumstellar maser emission similar to the IRAS two-color diagram. This new tool is especially useful for regions in the sky where IRAS was confused, in particular in the Galactic plane and bulge region. Unfortunately, using MSX colors alone does not allow one to distinguish between carbon-rich and oxygen-rich objects. An application of this tool on 86 GHz SiO masers shows that for this type of masers an instantaneous detection rate of 60% to 80% can be achieved if target sources are selected according to MSX color (region). Our investigations may have revealed an error in the MSX point source catalog version 2.3. That is, the photometry of the 21.3 mum (MSX E filter) band for most weak 8.28 mum (or MSX A filter) band sources seems off by about a factor 2 (0.5-1 mag too bright).

  5. 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

  6. 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.

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

    SciTech Connect

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

    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.

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Deemed IRAs in qualified employer plans. 1.408(q)-1 Section 1.408(q)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY.... § 1.408(q)-1 Deemed IRAs in qualified employer plans. (a) In general. Under section 408(q),...

  9. IRAS: High-Throughput Identification of Novel Alternative Splicing Regulators.

    PubMed

    Zheng, S

    2016-01-01

    Alternative splicing is a fundamental regulatory process of gene expression. Defects in alternative splicing can lead to various diseases, and modification of disease-causing splicing events presents great therapeutic promise. Splicing outcome is commonly affected by extracellular stimuli and signaling cascades that converge on RNA-binding splicing regulators. These trans-acting factors recognize cis-elements in pre-mRNA transcripts to affect spliceosome assembly and splice site choices. Identification of these splicing regulators and/or upstream modulators has been difficult and traditionally done by piecemeal. High-throughput screening strategies to find multiple regulators of exon splicing have great potential to accelerate the discovery process, but typically confront low sensitivity and low specificity of screening assays. Here we describe a unique screening strategy, IRAS (identifying regulators of alternative splicing), using a pair of dual-output minigene reporters to allow for sensitive detection of exon splicing changes. Each dual-output reporter produces green fluorescent protein (GFP) and red fluorescent protein (RFP) fluorescent signals to assay the two spliced isoforms exclusively. The two complementary minigene reporters alter GFP/RFP output ratios in the opposite direction in response to splicing change. Applying IRAS in cell-based high-throughput screens allows sensitive and specific identification of splicing regulators and modulators for any alternative exons of interest. In comparison to previous high-throughput screening methods, IRAS substantially enhances the specificity of the screening assay. This strategy significantly eliminates false positives without sacrificing sensitive identification of true regulators of splicing. PMID:27241759

  10. 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.

  11. Radar observations of Comet IRAS-Araki-Alcock 1983d

    SciTech Connect

    Harmon, J.K.; Hine, A.A.; Campbell, D.B.; Shapiro, I.I.; Marsden, B.G.

    1989-03-01

    A detailed analysis and interpretation of the Arecibo S-band radar observations of Comet IRAS-Araki-Alcock 1983d are presented. The very high signal strengths are used to make an accurate determination of the shape of the echo spectrum in the two orthogonal senses of circular polarization. The narrow-band component is used to place constraints on the size, rotation, period, reflectivity, and roughness of the nucleus. Detailed analysis of the broadband component yields estimates of, or bounds on, the spatial extent, position, and mass of the particle cloud, as well as the effective size of the constituent particles. 41 references.

  12. Nucleus of Comet IRAS-Araki-Alcock (1983 VII)

    NASA Technical Reports Server (NTRS)

    Sekanina, Z.

    1988-01-01

    Optical, radar, infrared, UV, and microwave-continuum observations of Comet IRAS-Araki-Alcok were obtained in May 1983, the week of the comet's close approach to earth. The comet has a nucleus dimension and a rotation period which are similar to those of Comet Halley, but a different morphological signature (a persisting sunward fan-shaped coma). Time variations are noted in the projected nucleus cross section. Results suggest significant limb-darkening effects in the relevant domains of radio waves, and that the comet's interior must be extremely cold. It is found that the thermal-infrared fluxes from the inner coma of the comet are dominated by the nucleus.

  13. Design of infrared astronomical satellite /IRAS/ primary mirror mounts

    NASA Technical Reports Server (NTRS)

    Schreibman, M.; Young, P.

    1980-01-01

    The design of an operational mount to rigidly secure the primary mirror to its baseplate without the introduction of figure error always proves to be a major task on diffraction limited optical systems. A summary of the design of the Infrared Astronomical Satellite (IRAS) primary mirror mount is given. The mirror was designed to be alligned and tested at room temperature and operated in a zero 'g' field at temperatures of 2K. To minimize overstressing, a stiffness requirement of greater than 150 Hz was required for cold launch and room temperature vibration acceptance testing. Additional isolation was required to minimize strains, introduced via the mounting base, due to thermal and mechanical distortions.

  14. IRAS galaxies and the large-scale structure in the CfA slice

    SciTech Connect

    Babul, A.; Postman, M. Space Telescope Science Institute, Baltimore, MD )

    1990-08-01

    The spatial distributions of the IRAS and the optical galaxies in the first CfA slice are compared. The IRAS galaxies are generally less clustered than optical ones, but their distribution is essentially identical to that of late-type optical galaxies. The discrepancy between the clustering properties of the IRAS and optical samples in the CfA slice region is found to be entirely due to the paucity of IRAS galaxies in the core of the Coma cluster. The spatial distributions of the IRAS and the optical galaxies, both late and early types, outside the dense core of the Coma cluster are entirely consistent with each other. This conflicts with the prediction of the linear biasing scenario. 39 refs.

  15. IRAS galaxies and the large-scale structure in the CfA slice

    NASA Technical Reports Server (NTRS)

    Babul, Arif; Postman, Marc

    1990-01-01

    The spatial distributions of the IRAS and the optical galaxies in the first CfA slice are compared. The IRAS galaxies are generally less clustered than optical ones, but their distribution is essentially identical to that of late-type optical galaxies. The discrepancy between the clustering properties of the IRAS and optical samples in the CfA slice region is found to be entirely due to the paucity of IRAS galaxies in the core of the Coma cluster. The spatial distributions of the IRAS and the optical galaxies, both late and early types, outside the dense core of the Coma cluster are entirely consistent with each other. This conflicts with the prediction of the linear biasing scenario.

  16. The census of complex organic molecules in the solar-type protostar IRAS16293-2422

    SciTech Connect

    Jaber, Ali A.; Ceccarelli, C.; Kahane, C.; Caux, E.

    2014-08-10

    Complex organic molecules (COMs) are considered to be crucial molecules, since they are connected with organic chemistry, at the basis of terrestrial life. More pragmatically, they are molecules which in principle are difficult to synthesize in harsh interstellar environments and, therefore, are a crucial test for astrochemical models. Current models assume that several COMs are synthesized on lukewarm grain surfaces (≳30-40 K) and released in the gas phase at dust temperatures of ≳100 K. However, recent detections of COMs in ≲20 K gas demonstrate that we still need important pieces to complete the puzzle of COMs formation. Here, we present a complete census of the oxygen- and nitrogen-bearing COMs, previously detected in different Interstellar Medium (ISM) regions, toward the solar-type protostar IRAS16293-2422. The census was obtained from the millimeter-submillimeter unbiased spectral survey TIMASSS. Of the 29 COMs searched for, 6 were detected: methyl cyanide, ketene, acetaldehyde, formamide, dimethyl ether, and methyl formate. Multifrequency analysis of the last five COMs provides clear evidence that they are present in the cold (≲30 K) envelope of IRAS16293-2422, with abundances of 0.03-2 × 10{sup –10}. Our data do not allow us to support the hypothesis that the COMs abundance increases with increasing dust temperature in the cold envelope, as expected if COMs were predominately formed on lukewarm grain surfaces. Finally, when also considering other ISM sources, we find a strong correlation over five orders of magnitude between methyl formate and dimethyl ether, and methyl formate and formamide abundances, which may point to a link between these two couples of species in cold and warm gas.

  17. The Census of Complex Organic Molecules in the Solar-type Protostar IRAS16293-2422

    NASA Astrophysics Data System (ADS)

    Jaber, Ali A.; Ceccarelli, C.; Kahane, C.; Caux, E.

    2014-08-01

    Complex organic molecules (COMs) are considered to be crucial molecules, since they are connected with organic chemistry, at the basis of terrestrial life. More pragmatically, they are molecules which in principle are difficult to synthesize in harsh interstellar environments and, therefore, are a crucial test for astrochemical models. Current models assume that several COMs are synthesized on lukewarm grain surfaces (gsim30-40 K) and released in the gas phase at dust temperatures of gsim100 K. However, recent detections of COMs in lsim20 K gas demonstrate that we still need important pieces to complete the puzzle of COMs formation. Here, we present a complete census of the oxygen- and nitrogen-bearing COMs, previously detected in different Interstellar Medium (ISM) regions, toward the solar-type protostar IRAS16293-2422. The census was obtained from the millimeter-submillimeter unbiased spectral survey TIMASSS. Of the 29 COMs searched for, 6 were detected: methyl cyanide, ketene, acetaldehyde, formamide, dimethyl ether, and methyl formate. Multifrequency analysis of the last five COMs provides clear evidence that they are present in the cold (lsim30 K) envelope of IRAS16293-2422, with abundances of 0.03-2 × 10-10. Our data do not allow us to support the hypothesis that the COMs abundance increases with increasing dust temperature in the cold envelope, as expected if COMs were predominately formed on lukewarm grain surfaces. Finally, when also considering other ISM sources, we find a strong correlation over five orders of magnitude between methyl formate and dimethyl ether, and methyl formate and formamide abundances, which may point to a link between these two couples of species in cold and warm gas.

  18. IRAS 16293-2422: Evidence for Infall onto a Counter-Rotating Protostellar Accretion Disk

    NASA Technical Reports Server (NTRS)

    Remijan, Anthony J.; Hollis, J. M.

    2005-01-01

    We report high spatial resolution VLA observations of the low-mass star-forming region IRAS 16293-2422 using four molecular probes: ethyl cyanide (CH3CH2CN)) methyl formate (CH3OCHO), formic acid (HCOOH), and the ground vibrational state of silicon monoxide (SiO). Ethyl cyanide emission has a spatial scale of approx. 20" and encompasses binary cores A and B as determined by continuum emission peaks. Surrounded by formic acid emission, methyl formate emission has a spatial scale of approx. 6" and is confined to core B. SiO emission shows two velocity components with spatial scales less than 2" that map approx. 2" northeast of the A and B symmetry axis. The redshifted SiO is approx. 2" northwest of blueshifted SiO along a position angle of approx. 135deg which is approximately parallel to the A and B symmetry axis. We interpret the spatial position offset in red and blueshifted SiO emission as due to rotation of a protostellar accretion disk and we derive approx. 1.4 Solar Mass, interior to the SiO emission. In the same vicinity, Mundy et al. (1986) also concluded rotation of a nearly edge-on disk from OVRO observations of much stronger and ubiquitous CO-13 emission but the direction of rotation is opposite to the SiO emission findings. Taken together, SiO and CO-13 data suggest evidence for a counter-rotating disk. Moreover, archival BIMA array CO-12C data show an inverse P Cygni profile with the strongest absorption in close proximity to the SiO emission, indicating unambiguous material infall toward the counter-rotating protostellar disk at a new source location within the IRAS 16293-2422 complex. The details of these observations and our interpretations are discussed.

  19. Helical Magnetic Fields in the NGC 1333 IRAS 4A Protostellar Outflows

    NASA Astrophysics Data System (ADS)

    Ching, Tao-Chung; Lai, Shih-Ping; Zhang, Qizhou; Yang, Louis; Girart, Josep M.; Rao, Ramprasad

    2016-03-01

    We present Submillimeter Array polarization observations of the CO J = 3-2 line toward NGC 1333 IRAS 4A. The CO Stokes I maps at an angular resolution of ˜1″ reveal two bipolar outflows from the binary sources of NGC 1333 IRAS 4A. The kinematic features of the CO emission can be modeled by wind-driven outflows at ˜20° inclined from the plane of the sky. Close to the protostars the CO polarization, at an angular resolution of ˜2.″3, has a position angle approximately parallel to the magnetic field direction inferred from the dust polarizations. The CO polarization direction appears to vary smoothly from an hourglass field around the core to an arc-like morphology wrapping around the outflow, suggesting a helical structure of magnetic fields that inherits the poloidal fields at the launching point and consists of toroidal fields at a farther distance of outflow. The helical magnetic field is consistent with the theoretical expectations for launching and collimating outflows from a magnetized rotating disk. Considering that the CO polarized emission is mainly contributed from the low-velocity and low-resolution data, the helical magnetic field is likely a product of the wind-envelope interaction in the wind-driven outflows. The CO data reveal a PA of ˜30° deflection in the outflows. The variation in the CO polarization angle seems to correlate with the deflections. We speculate that the helical magnetic field contributes to ˜10° deflection of the outflows by means of Lorentz force.

  20. Water deuterium fractionation in the low-mass protostar NGC1333-IRAS2A

    NASA Astrophysics Data System (ADS)

    Liu, F.-C.; Parise, B.; Kristensen, L.; Visser, R.; van Dishoeck, E. F.; Güsten, R.

    2011-03-01

    Context. Although deuterium enrichment of water may provide an essential piece of information in the understanding of the formation of comets and protoplanetary systems, only a few studies up to now have aimed at deriving the HDO/H2O ratio in low-mass star forming regions. Previous studies of the molecular deuteration toward the solar-type class 0 protostar, IRAS 16293-2422, have shown that the D/H ratio of water is significantly lower than other grain-surface-formed molecules. It is not clear if this property is general or particular to this source. Aims: In order to see if the results toward IRAS 16293-2422 are particular, we aimed at studying water deuterium fractionation in a second low-mass solar-type protostar, NGC1333-IRAS2A. Methods: Using the 1-D radiative transfer code RATRAN, we analyzed five HDO transitions observed with the IRAM 30 m, JCMT, and APEX telescopes. We assumed that the abundance profile of HDO in the envelope is a step function, with two different values in the inner warm (T > 100 K) and outer cold (T < 100 K) regions of the protostellar envelope. Results: The inner and outer abundance of HDO is found to be well constrained at the 3σ level. The obtained HDO inner and outer fractional abundances are xHDO_in = 6.6 × 10-8-1.0 × 10-7(3σ) and x^{HDO}out=9×10-11= 9 × 10-11-1.0-1.8 × 10-9(3σ). These values are close to those in IRAS 16293-2422, which suggests that HDO may be formed by the same mechanisms in these two solar-type protostars. Taking into account the (rather poorly onstrained) H2O abundance profile deduced from Herschel observations, the derived HDO/H2O in the inner envelope is ≥1% and in the outer envelope it is 0.9%-18%. These values are more than one order of magnitude higher than what is measured in comets. If the same ratios apply to the protosolar nebula, this would imply that there is some efficient reprocessing of the material between the protostellar and cometary phases. Conclusions: The H2O inner fractional

  1. A quantitative analysis of IRAS maps of molecular clouds

    NASA Technical Reports Server (NTRS)

    Wiseman, Jennifer J.; Adams, Fred C.

    1994-01-01

    We present an analysis of IRAS maps of five molecular clouds: Orion, Ophiuchus, Perseus, Taurus, and Lupus. For the classification and description of these astrophysical maps, we use a newly developed technique which considers all maps of a given type to be elements of a pseudometric space. For each physical characteristic of interest, this formal system assigns a distance function (a pseudometric) to the space of all maps: this procedure allows us to measure quantitatively the difference between any two maps and to order the space of all maps. We thus obtain a quantitative classification scheme for molecular clouds. In this present study we use the IRAS continuum maps at 100 and 60 micrometer(s) to produce column density (or optical depth) maps for the five molecular cloud regions given above. For this sample of clouds, we compute the 'output' functions which measure the distribution of density, the distribution of topological components, the self-gravity, and the filamentary nature of the clouds. The results of this work provide a quantitative description of the structure in these molecular cloud regions. We then order the clouds according to the overall environmental 'complexity' of these star-forming regions. Finally, we compare our results with the observed populations of young stellar objects in these clouds and discuss the possible environmental effects on the star-formation process. Our results are consistent with the recently stated conjecture that more massive stars tend to form in more 'complex' environments.

  2. A quantitative analysis of IRAS maps of molecular clouds

    NASA Astrophysics Data System (ADS)

    Wiseman, Jennifer J.; Adams, Fred C.

    1994-11-01

    We present an analysis of IRAS maps of five molecular clouds: Orion, Ophiuchus, Perseus, Taurus, and Lupus. For the classification and description of these astrophysical maps, we use a newly developed technique which considers all maps of a given type to be elements of a pseudometric space. For each physical characteristic of interest, this formal system assigns a distance function (a pseudometric) to the space of all maps: this procedure allows us to measure quantitatively the difference between any two maps and to order the space of all maps. We thus obtain a quantitative classification scheme for molecular clouds. In this present study we use the IRAS continuum maps at 100 and 60 micrometer(s) to produce column density (or optical depth) maps for the five molecular cloud regions given above. For this sample of clouds, we compute the 'output' functions which measure the distribution of density, the distribution of topological components, the self-gravity, and the filamentary nature of the clouds. The results of this work provide a quantitative description of the structure in these molecular cloud regions. We then order the clouds according to the overall environmental 'complexity' of these star-forming regions. Finally, we compare our results with the observed populations of young stellar objects in these clouds and discuss the possible environmental effects on the star-formation process. Our results are consistent with the recently stated conjecture that more massive stars tend to form in more 'complex' environments.

  3. Analysis of interstellar cloud structure based on IRAS images

    NASA Technical Reports Server (NTRS)

    Scalo, John M.

    1992-01-01

    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 densely sampled column density maps of star-forming clouds, column density images of four nearby cloud complexes were constructed from IRAS data. The regions have various degrees of star formation activity, and most of them have probably not been affected much by the disruptive effects of young massive stars. The largest region, the Scorpius-Ophiuchus cloud complex, covers about 1000 square degrees (it was subdivided into a few smaller regions for analysis). Much of the work during the early part of the project focused on an 80 square degree region in the core of the Taurus complex, a well-studied region of low-mass star formation.

  4. Ira Maximilian Altshuler: psychiatrist and pioneer music therapist.

    PubMed

    Davis, William B

    2003-01-01

    The purpose of this study was to examine the life of Ira Maximilian Altshuler, psychiatrist and pioneer music therapist. In 1938, Dr. Altshuler initiated one of the first large-scale music therapy programs for mentally ill persons in the country at Detroit's Eloise Hospital. His innovative programs combined psychoanalytic techniques and music therapy methods specifically designed for use with large groups of clients. He later trained some of the first music therapy interns in the country, including Carol Collins, who served for many years as Professor of Music Therapy at Wayne State University, and Esther Goetz Gilliland, who later became President of NAMT. Dr. Altshuler promoted the practice and profession tirelessly, speaking to numerous audiences over the years and writing 19 articles about music therapy. Altshuler participated in the National Association for Music Therapy (NAMT) organizational meeting held in New York City in 1950. An active member of the organization for many years, he served on the Research Committee and hosted the 1955 national NAMT conference in Detroit. Even after Altshuler's retirement from Eloise Hospital in 1963, he remained active in numerous civic, music, and music therapy activities until his death 5 year later. Ira Altshuler should be remembered along with other music therapists from the time-Willem Van de Wall, Harriet Ayer Seymour and others-who vigorously embraced and advanced the status of the profession. PMID:14567731

  5. Ira at 80: The acronyms of a career in acoustics

    NASA Astrophysics Data System (ADS)

    Weisenberger, Janet M.

    2002-05-01

    In a career that spans some 54 years to date, the name of Ira J. Hirsh has been associated with significant scientific contributions to psychoacoustics, outstanding mentoring of research scientists, and dedicated service to the fields of acoustics, audiology, and psychology. It is a career that can be traced by acronyms that are part of the daily vocabulary of hearing scientists. These include acronyms of location: Early work at the Psychoacoustics Laboratory at Harvard (PAL), a long tenure in research at the Central Institute for the Deaf (CID), service as faculty member, chair, and dean at Washington University (WashU); acronyms of professional societies that have honored him: Acoustical Society of America (ASA), International Commission of Acoustics (ICA), American Psychological Association (APA), American Psychological Society (APS), American Speech-Language-Hearing Association (ASHA), American Association for the Advancement of Science (AAAS); acronyms of his service to the National Academy of Science: National Research Council (NRC), Commission on Behavioral and Social Science and Education (CBASSE); and acronyms of his contributions to psychoacoustics: Masking Level Difference (MLD), Temporal Order Judgments (TOJ). In large part, these acronyms are part of our vocabulary because of Ira's contributions, and tracing them over the past half-century yields a substantive look at the development of the field of hearing science.

  6. Luminous asymptotic giant branch stars in the Large Magellanic Cloud

    NASA Technical Reports Server (NTRS)

    Reid, Neill; Tinney, Chris; Mould, Jeremy

    1990-01-01

    A search has been conducted for optically obscured asymptotic giant branch (AGB) stars in the LMC. The results obtained are noted to rule out the presence of sufficient high-luminosity 'cocoon' stars to explain the observed deficit of several hundred luminous AGB stars between the predictions of standard AGB evolution models and the observed luminosity function. Bolometric magnitudes as low as -5 are inferred for these sources; it is suggested that this phase can be triggered at low luminosities, truncating AGB evolution and leading to the observed scarcity of AGBs with M(bol) greater than -6.0 mag.

  7. 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. PMID:19532196

  8. From the ashes: JVLA observations of water fountain nebula candidates show the rebirth of IRAS 18455+0448

    NASA Astrophysics Data System (ADS)

    Vlemmings, W. H. T.; Amiri, N.; van Langevelde, H. J.; Tafoya, D.

    2014-09-01

    Context. The class of water fountain nebulae is thought to represent the stage of the earliest onset of collimated bipolar outflows during the post-asymptotic giant branch phase. They thus play a crucial role in the study of the formation of bipolar planetary nebulae (PNe). To date, 14 water fountain nebulae have been identified. The identification of more sources in this unique stage of stellar evolution will enable us to study the origin of bipolar PNe morphologies in more detail. Aims: Water fountain candidates can be identified based on the often double peaked 22 GHz H2O maser spectrum with a large separation between the maser peaks (often >100 km s-1). However, even a fast bipolar outflow will only have a moderate velocity extent in its maser spectrum when located close to the plane of the sky. In this project we aim to enhance the water fountain sample by identifying objects whose jets are aligned close to the plane of the sky. Methods: We present the results of seven sources observed with the Jansky Very Large Array (JVLA) that were identified as water fountain candidates in an Effelsberg 100 m telescope survey of 74 AGB and early post-AGB stars. Results: We find that our sample of water fountain candidates displays strong variability in their 22 GHz H2O maser spectra. The JVLA observations show an extended bipolar H2O maser outflow for one source, the OH/IR star IRAS 18455+0448. This source was previously classified as a dying OH/IR star based on the exponential decrease of its 1612 MHz OH maser and the lack of H2O masers. We therefore also re-observed the 1612, 1665, and 1667 MHz OH masers. We confirm that the 1612 MHz masers have not reappeared and find that the1665/1667 MHz masers have decreased in strength by several orders of magnitude during the last decade. The JVLA observations also reveal a striking asymmetry in the red-shifted maser emission of IRAS 19422+3506. Conclusions: The OH/IR star IRAS 18455+0448 is confirmed to be a new addition to the

  9. ISO Detection of CO(+) toward the protostar IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Ceccarelli, C.; Caux, E.; Wolfire, M.; Rudolph, A.; Nisini, B.; Saraceno, P.; White, G. J.

    1998-03-01

    In this letter we report the detection of eight high-N rotational transitions of CO(+) towards a low mass protostar, IRAS 16293-2422. The source was observed with the Long Wavelength Spectrometer on board the Infrared Space Observatory. This is the first time that CO(+) has been detected in a low luminosity source and the first time that high-N lines have been detected in any source. The detection of these lines was not predicted by models and consequently, their interpretation is a challenge. We discuss the possibility that the observed CO(+) emission originates in the dense inner regions illuminated by the UV field created in the accretion shock (formed by infalling material), and conclude that this is an improbable explanation. We have also considered the possibility that a strong, dissociative J-shock at ~ 500 AU from the star is the origin of the CO(+) emission. This model predicts CO(+) column densities in rough agreement with the observations if the magnetic field is ~ 1 mG and the shock velocity is 100 km s(-1) . Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA.

  10. ISO Detection of CO(+) toward the Protostar IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Rudolph, A.; Ceccarelli, C.; Caux, E.; Wolfire, M.; Nisini, B.; Saraceno, P.; White, G. J.

    1997-12-01

    We report the detection of eight high-N rotational transitions of CO(+) towards a low mass protostar, IRAS 16293-2422. The source was observed with the Long Wavelength Spectrometer on board the Infrared Space Observatory. This is the first time that CO(+) has been detected in a low luminosity source and the first time that high-N lines have been detected in any source. The detection of these lines is totally unpredicted by models and, consequently, their interpretation is a challenge. We discuss the possibility that the observed CO(+) emission originates in the dense inner regions illuminated by the UV field created in the accretion shock (formed by the infalling material), and conclude that this is an improbable explanation. We have also considered the possibility that a strong, dissociative J-shock at ~ 500 AU from the star is the origin of the CO(+) emission. This model predicts CO(+) column densities in rough agreement with the observations if the magnetic field is ~ 1 mG and the shock velocity is 100 km s(-1) .

  11. Dosimetric comparison of four new design {sup 103}Pd brachytherapy sources: Optimal design using silver and copper rod cores

    SciTech Connect

    Hosseini, S. Hamed; Sadeghi, Mahdi; Ataeinia, Vahideh

    2009-07-15

    Four new brachytherapy sources, IRA1-{sup 103}Pd, IRA2-{sup 103}Pd, IRA3-{sup 103}Pd, and IRA4-{sup 103}Pd, have been developed at Agricultural, Medical, and Industrial Research School and are designed for permanent implant application. With the goal of determining an optimal design for a {sup 103}Pd source, this article compares the dosimetric properties of these sources with reference to the authors' earlier IRA-{sup 103}Pd source. The four new sources differ in end cap configuration and thickness and in the core material, silver or copper, that carries the adsorbed {sup 103}Pd. Dosimetric data derived from the authors' Monte Carlo simulation results are reported in accordance with the updated AAPM Task Group No. 43 report (TG-43U1). For each source, the authors obtained detailed results for the dose rate constant {Lambda}, the radial dose function g(r), the anisotropy function F(r,{theta}), and the anisotropy factor {phi}{sub an}(r). In this study, the optimal source IRA3-{sup 103}Pd provides the most isotropic dose distribution in water with the dose rate constant of 0.678({+-}0.1%) cGy h{sup -1} U{sup -1}. The IRA3-{sup 103}Pd design has a silver rod core combined with thin-wall, concave end caps. Finally, the authors compared the results for their optimal source with published results for those of other source manufacturers.

  12. A redshift survey of IRAS galaxies. V - The acceleration on the Local Group

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    The acceleration on the Local Group is calculated based on a full-sky redshift survey of 5288 galaxies detected by IRAS. A formalism is developed to compute the distribution function of the IRAS acceleration for a given power spectrum of initial perturbations. The computed acceleration on the Local Group points 18-28 deg from the direction of the Local Group peculiar velocity vector. The data suggest that the CMB dipole is indeed due to the motion of the Local Group, that this motion is gravitationally induced, and that the distribution of IRAS galaxies on large scales is related to that of dark matter by a simple linear biasing model.

  13. An Abundance Analysis of Two Carbon-Rich Proto-Planetary Nebulae: IRAS Z02229+6208 And IRAS 07430+1115

    NASA Technical Reports Server (NTRS)

    Reddy, Bacham E.; Bakker, Eric J.; Hrivnak, Bruce J.

    1999-01-01

    In this paper, we present an LTE abundance analysis of two new proto-planetary nebulae, IRAS Z02229 + 6208 and IRAS 07430 + 1115, based on high-resolution (R approximately equal 55,000) optical echelle spectra. Results show that both stars are metal-poor ([Fe/H] = -0.5) and overabundant in C, N, and s-process elements. The average elemental abundances are [C/Fe] = +0.8, [N/Fe] = +1.2, and [s-process/Fe] = +1.4 for IRAS Z02229 + 6208, and [C/Fe] = +0.6, [N/Fe] = +0.4, and [s-process/Fe] = +1.6 for IRAS 07430+ 1115. These abundances suggest that the stars have experienced nucleo-synthesis on the asymptotic giant branch (AGB), and the resultant products of CNO, 3alpha, and s-process reactions were brought to the photosphere during shell flashes and deep mixing episodes during the AGB phase of their evolution. Of major significance is the measurement of a high Li abundance in both stars, log epsilon(Li) approximately equal 2.3 and 2.4 for IRAS Z02229 + 6208 and IRAS 07430 + 1115, respectively. This may be the result of hot bottom burning, below the deep convective zone. We also present an analysis of the circumstellar molecular (C2 and CN) and atomic (Na I and K I) absorption spectra of both stars. We derive rotational temperatures, column densities, and envelope expansion velocities using molecular C2 Phillips and CN Red system bands. The values derived for expansion velocities, 8-14 km/s, are typical of the values found for post-AGB stars. IRAS 07430+ 1115 is unusual in that it shows P Cygni-shaped C2 emission profiles in the spectra of the circumstellar envelope. A minimum distance for IRAS Z02229+6208, determined from interstellar Na I lines, suggests that it is evolved from an intermediate-mass star. Including these two stars, the number of post-AGB stars for which clear C, N, and s-process elemental overabundances are found rises to eight. IRAS Z02229 + 6208 is known to possess the 21 micron emission feature in its mid-infrared spectrum; these results support the

  14. Circumstellar shells resolved in IRAS survey data. II - Analysis

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    IRAS survey data for 512 red giant stars and young planetary nebulae were processed using a computer program which fitted the data to an idealized model of a circumstellar shell. Seventy-six of these stars were found to have circumstellar shells resolved in the 60-micron survey data. Forty pct of the 76 stars are carbon stars. Thirteen are Mira variables. The evolution of these shells, involving the interaction of the expelled material with the ISM, is modeled, and the results suggest that the period during which Mira variables lose mass lasts for approximately 10 exp 5 yr. Carbon stars are found to shed mass for about 2 x 10 exp 5 yr. The expansion velocity of the outer shell for the largest shells will normally be lower by a factor of 3-5 than the expansion velocity obtained from CO observations.

  15. IRAS observations of a small sample of blue irregular galaxies

    NASA Technical Reports Server (NTRS)

    Hunter, D. A.; Gillett, F. C.; Gallagher, J. S., III; Rice, W. L.; Low, F. J.

    1986-01-01

    IRAS satellite IR observations are presently used to investigate the properties of the dust in a small sample of irregular galaxies chosen to cover a wide range in levels of star formation activity. The irregulars are found to have comparatively normal IR properties; the only exception is NGC 1569, an irregular galaxy with intense global star formation which seems to have a larger dust fraction at temperatures whose energies peak at 25-60 microns, by comparison with other irregulars. DDO 47, the system with lowest star formation activity, has the lowest far-IR color temperature and highest ratio of IR to H-alpha flux; this is suggested to be due to the decreased importance of radiation from young stars in heating the dust.

  16. IRAS observations of giant molecular clouds in the Milky Way

    NASA Technical Reports Server (NTRS)

    Mozurkewich, D.; Thronson, H. A., Jr.

    1986-01-01

    The IRAS data base has been used to study infrared radiation from molecular clouds in our galaxy. The sample of clouds was restricted to those with reliably determined molecular masses from large area, multi-isotope CO maps. They were normalized to X(CO-13)= 2x10 to the -6. Flux densities at 60 microns and 100 microns were determined by integrating the flux density within rectangles drawn on the sky flux plates after subtracting a suitable background. The rectangles were chosen to be coextensive with the areas mapped in CO. Color corrections were made and luminosites calculated by assuming the optical depths were proportional to frequency. The flux densities were converted to dust masses with a value for 4a rho/3Q = .04 g/cm at 100 microns.

  17. IRAS 04302+2247: Butterfly star in Taurus!

    NASA Astrophysics Data System (ADS)

    Lucas, Philip; Roche, Patrick F.

    1997-02-01

    We present near infrared observations of IRAS 04302+2247, a Class I protostar in the Taurus-Auriga molecular cloud complex whose equatorial plane is inclined precisely edge-on to the line of sight (i=90°+/-4°). This system displays a unique quadrupolar morphology, which had not been previously predicted in any simulations of a single protostar. We use the Monte Carlo method to tailor a model to our imaging and polarimetric data, and we explain the quadrupolar structure in terms of a dusty jet or outflow which lies perpendicular to the equatorial plane. We constrain the circumstellar structure to the form of an equatorially condensed envelope with a concave bipolar cavity. The circumstellar disk is not seen, which requires that it is physically thin. With its convenient orientation and proximity (d=140 pc) this system should yield many insights into the Class I phase of evolution.

  18. Near-infrared observations of IRAS minisurvey galaxies

    NASA Technical Reports Server (NTRS)

    Carico, D. P.; Soifer, B. T.; Elias, J. H.; Matthews, K.; Neugebauer, G.; Beichman, C.

    1986-01-01

    Near-infrared photometry was obtained for 82 galaxies from the Infrared Astronomy Satellite (IRAS) minisurvey, a sample of infrared selected galaxies. The near-infrared colors of these galaxies are similar to those of normal field spiral galaxies, but cover a larger range in J - H and H - K. There is evidence of a tighter correlation between the near and far infrared emission than exists between far-infrared and the visible emission. These results suggest that hot dust emission contributes to the 2.2 micron luminosity, and extinction by dust affects both the near-infrared colors and the visible luminosities. In addition, there is an indication that the far-infrared emission in many of the minisurvey galaxies is coming from a strong nuclear component.

  19. Radio occultation experiments with INAF-IRA radiotelescopes.

    NASA Astrophysics Data System (ADS)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.

    The Radio Occultation research program performed at the Medicina and Noto Radioastronomical Stations of the Istituto Nazionale di Astrofisica (INAF) - Istituto di Radioastronomia (IRA) includes observations of spacecraft by satellite and satellite by satellite events. The Lunar Radio Occultation (LRO) part of the program consists in collecting data of the lunar Total Electron Content (TEC), at different limb longitudes and at different time, in order to study long term variation of the Moon's ionosphere. The LRO program started at Medicina in September 2006 with the observation of the European probe SMART-1 during its impact on the lunar soil. It proceeded in 2007 with the observation of the lunar occultations of Saturn and Venus, and with the observation of Mars in 2008. On this occasion the probes Cassini, Venus Express, Mars Express, Mars Reconaissance Orbiter and Mars Odissey were respectively occulted by the moon. On Dec 1st 2008 a Venus lunar occultation occurred. On that occasion we performed the first Italian-VLBI (I-VLBI) tracking experiment by detecting the carrier signals coming from the Venus Express (VEX) spacecraft with both the IRA radiotelescopes together with the Matera antenna of the Italian Space Agency. The second part of the radio occultation program includes the observation of satellite by satellite occultation events, as well as mutual occultations of Jupiter satellites. These events are referred to as mutual phenomena (PHEMU). These observations are aimed to measure the radio flux variation during the occultation and to derive surface spatial characteristics such as Io's hot spots. In this work preliminary results of the Radio Occultation program will be presented.

  20. SPECTRAL VARIABILITY OF IRAS 18325-5926 AND CONSTRAINTS ON THE GEOMETRY OF THE SCATTERING MEDIUM

    SciTech Connect

    Tripathi, Shruti; Misra, R.; Dewangan, G. C.; Cheeran, J.; Abraham, S.; Philip, N. S.

    2013-08-20

    We analyze Suzaku and XMM-Newton data of the highly variable Seyfert 2, IRAS 18325-5926. The spectra of the source are well modeled as a primary component described as an absorbed power law and a secondary power-law component which is consistent with being scattered emission from an on-axis extended highly ionized medium. We show that while the primary component varies on a wide range of timescales from 10{sup 4}-10{sup 8} s, the scattered emission is variable only on timescales longer than 10{sup 5} s. This implies that the extent of the scattering medium is greater than 10{sup 16} cm. The ratio of the scattered to primary flux ({approx}0.03) implies a column density for the scattering medium to be {approx}10{sup 23} cm{sup -2}. We argue that for such a medium to be highly ionized it must be located less than 10{sup 17} cm from the X-ray source. Thus, we localize the position and extent of scattering region to be {approx}a few Multiplication-Sign 10{sup 16} cm, with an average particle density of {approx}10{sup 6} cm{sup -3}. We consider the physical interpretation of these results, and as an aside we confirm the presence of a broad iron line emission in both the XMM-Newton and Suzaku observations.

  1. Infrared and visible detector electronics for the Infrared Astronomical Satellite (IRAS)

    NASA Astrophysics Data System (ADS)

    Langford, D. L.; Simmonds, J. J.; Ozawa, T.; Long, E. C.; Paris, R.

    1984-01-01

    The paper describes the detectors, preamplifiers, and processing electronics; the system characterization test methods and results; and the performance of the detectors and electronics during the first month of on-orbit operation of the IRAS telescope. The Focal Plane Array (FPA) consists of 62 IR channels and 8 visible channels operating at 2.5 K. The IR detectors are grouped in eight 7 or 8 channel staggered linear subarrays with shared bias voltage; the visible detectors are grouped in two 4 channel skewed arrays, also with shared bias. Each channel detector is dc coupled to a TIA preamplifier through a very low power thermally isolated JFET source follower operating at about 65 K within the FPA housing. The visible channel detectors are ac coupled to TIA preamplifiers and signal chain electronics using MOSFET source followers operating at about 2.5 K within the FPA housing. The detectors, preamplifiers, analog electronics, and grounding are discussed as they evolved and were implemented during FPA retrofit, telescope integration, and preparation for launch.

  2. Multiple monopolar outflows driven by massive protostars in IRAS 18162-2048

    SciTech Connect

    Fernández-López, M.; Girart, J. M.; Curiel, S.; Fonfría, J. P.; Zapata, L. A.; Qiu, K. E-mail: girart@ieec.cat

    2013-11-20

    In this article, we present Combined Array for Research in Millimeter-wave Astronomy (CARMA) 3.5 mm observations and SubMillimeter Array (SMA) 870 μm observations toward the high-mass star-forming region IRAS 18162-2048, which is the core of the HH 80/81/80N system. Molecular emission from HCN, HCO{sup +}, and SiO traces two molecular outflows (the so-called northeast and northwest outflows). These outflows have their origin in a region close to the position of MM2, a millimeter source known to harbor two protostars. For the first time we estimate the physical characteristics of these molecular outflows, which are similar to those of 10{sup 3}-5 × 10{sup 3} L {sub ☉} protostars, and suggest that MM2 harbors high-mass protostars. High-angular resolution CO observations show an additional outflow due southeast. Also for the first time, we identify its driving source, MM2(E), and see evidence of precession. All three outflows have a monopolar appearance, but we link the NW and SE lobes, and explain their asymmetric shape as being a consequence of possible deflection.

  3. Prostate cancer stem cells: do they have a basal or luminal phenotype?

    PubMed

    Maitland, Norman J; Frame, Fiona M; Polson, Euan S; Lewis, John L; Collins, Anne T

    2011-02-01

    The prostate is a luminal secretory tissue whose function is regulated by male sex hormones. Castration produces involution of the prostate to a reversible basal state, and as the majority of prostate cancers also have a luminal phenotype, drug-induced castration is a front line therapy. It has therefore been assumed that the tumor arises from transformation of a luminal progenitor cell. Here, we demonstrate that a minority basal "cancer stem cell" (CSC) population persists in primary human prostate cancers, as in normal prostate, serving as a reservoir for tumor recurrence after castration therapy. While the CSCs exhibit a degree of phenotypic fluidity from different patients, the tumor-initiating cells in immunocompromised mice express basal markers (such as p63), but do not express androgen receptor (AR) or markers of luminal differentiation (PSA, PAP) when freshly fractionated from human tissues or following culture in vitro. Estrogen receptors α and β and AR are transcriptionally active in the transit amplifying (TA) cell (the progeny of SC). However, AR protein is consistently undetectable in TA cells. The prostate-specific TMPRSS2 gene, while upregulated by AR activity in luminal cells, is also transcribed in basal populations, confirming that AR acts as an expression modulator. Selected cells with basal phenotypes are tumor initiating, but the resultant tumors are phenotypically intermediate, with focal expression of AR, AMACR, and p63. In vitro differentiation experiments, employing lentivirally transduced SCs with a luminal (PSA-probasin) promoter regulating a fluorescent indicator gene, confirm that the basal SCs are the source of luminal progeny. PMID:21761340

  4. Adaptive Optics Imaging Survey of Luminous Infrared Galaxies

    SciTech Connect

    Laag, E A; Canalizo, G; van Breugel, W; Gates, E L; de Vries, W; Stanford, S A

    2006-03-13

    We present high resolution imaging observations of a sample of previously unidentified far-infrared galaxies at z < 0.3. The objects were selected by cross-correlating the IRAS Faint Source Catalog with the VLA FIRST catalog and the HST Guide Star Catalog to allow for adaptive optics observations. We found two new ULIGs (with L{sub FIR} {ge} 10{sup 12} L{sub {circle_dot}}) and 19 new LIGs (with L{sub FIR} {ge} 10{sup 11} L{sub {circle_dot}}). Twenty of the galaxies in the sample were imaged with either the Lick or Keck adaptive optics systems in H or K{prime}. Galaxy morphologies were determined using the two dimensional fitting program GALFIT and the residuals examined to look for interesting structure. The morphologies reveal that at least 30% are involved in tidal interactions, with 20% being clear mergers. An additional 50% show signs of possible interaction. Line ratios were used to determine powering mechanism; of the 17 objects in the sample showing clear emission lines--four are active galactic nuclei and seven are starburst galaxies. The rest exhibit a combination of both phenomena.

  5. Morphological classification of local luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Psychogyios, A.; Charmandaris, V.; Diaz-Santos, T.; Armus, L.; Haan, S.; Howell, J.; Le Floc'h, E.; Petty, S. M.; Evans, A. S.

    2016-06-01

    We present analysis of the morphological classification of 89 luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey (GOALS) sample, using non-parametric coefficients and compare their morphology as a function of wavelength. We rely on images that were obtained in the optical (B- and I-band) as well as in the infrared (H-band and 5.8 μm). Our classification is based on the calculation of Gini and the second order of light (M20) non-parametric coefficients, which we explore as a function of stellar mass (M⋆), infrared luminosity (LIR), and star formation rate (SFR). We investigate the relation between M20, the specific SFR (sSFR) and the dust temperature (Tdust) in our galaxy sample. We find that M20 is a better morphological tracer than Gini, as it allows us to distinguish systems that were formed by double systems from isolated and post-merger LIRGs. The effectiveness of M20 as a morphological tracer increases with increasing wavelength, from the B to H band. In fact, the multi-wavelength analysis allows us to identify a region in the Gini-M20 parameter space where ongoing mergers reside, regardless of the band used to calculate the coefficients. In particular, when measured in the H band, a region that can be used to identify ongoing mergers, with minimal contamination from LIRGs in other stages. We also find that, while the sSFR is positively correlated with M20 when measured in the mid-infrared, i.e. star-bursting galaxies show more compact emission, it is anti-correlated with the B-band-based M20. We interpret this as the spatial decoupling between obscured and unobscured star formation, whereby the ultraviolet/optical size of an LIRG experience an intense dust-enshrouded central starburst that is larger that in the mid-infrared since the contrast between the nuclear to the extended disk emission is smaller in the mid-infrared. This has important implications for high redshift surveys of dusty sources, where sizes of galaxies

  6. The structure of the nearby universe traced by theIRAS galaxies

    NASA Technical Reports Server (NTRS)

    Yahil, Amos

    1993-01-01

    One of the most important discoveries of the Infrared Astronomical Satellite (IRAS) has been the detection of about 20,000 galaxies with 60 microns fluxes above 0.5 Jy. From the observational point of view, the IRAS galaxies are ideal tracers of density, since they are homogeneously detected over most of the sky, and their fluxes are unaffected by galactic extinction. The nearby universe was mapped by the IRAS galaxies to a distance of approximately 200 h(exp -1) Mpc for the absolute value of b less than 5 deg. The ability to map down to such low galactic latitudes has proven to be particularly imporant, since some of the most important nearby large-scale structures, such as the Great Attractor, the Perseus-Pisces region, and the Shapley concentration, all lie there. Two major results of the U.S. IRAS redshift survey are discussed.

  7. Using the IRAS data to search in the asteroid belt for any potential evidence of galactic colonization

    NASA Technical Reports Server (NTRS)

    Papagiannis, M. D.

    1986-01-01

    The end product of the biological evolution seems to be the appearance of technological civilizations, which are characterized by superior technology that supercedes biological capabilities. The Search for Extraterrestrial Intelligence (SETI) has gained scientific recognition in recent years. The concept of galactic colonization is debated extensively, with opinions ranging from the impossible to the inevitable, but without a clear resolution. Answers can be obtained only with experimental tests and not with endless debates. A search for large space colonies in the asteroid belt, an ideal source of raw materials for a spaceborne civilization, is a test of the galactic colonization theory. The catalogue of solar system objects obtained form the Infrared Astronomy Satellite (IRAS) observations at 12, 25, 60, and 100 microns, is an ideal source for such a search. The catalog is expected to be ready at the end of 1985 and will contain more than 10,000 objects.

  8. Physical properties and evolutionary state of the Lyman alpha emitting starburst galaxy IRAS 08339+6517

    NASA Astrophysics Data System (ADS)

    Otí-Floranes, H.; Mas-Hesse, J. M.; Jiménez-Bailón, E.; Schaerer, D.; Hayes, M.; Östlin, G.; Atek, H.; Kunth, D.

    2014-06-01

    Context. Though Lyα emission is one of the most used tracers of massive star formation at high redshift, it is strongly affected by neutral gas radiation transfer effects. A correct understanding of these effects is required to properly quantify the star formation rate along the history of the Universe. Aims: We aim to parameterize the escape of Lyα photons as a function of the galaxy properties, in order to properly calibrate the Lyα luminosity as a tracer of star formation intensity at any age of the Universe. Methods: We have embarked on a program to study the properties of the Lyα emission (spectral profile, spatial distribution, relation to Balmer lines intensity,...) in a number of starburst galaxies in the Local Universe. The study is based on Hubble Space Telescope spectroscopic and imaging observations at various wavelengths, X-ray data, and ground-based spectroscopy, complemented with the use of evolutionary population synthesis models. Results: We present here the results obtained for one of those sources, IRAS 08339+6517, a strong Lyα emitter in the Local Universe, which is undergoing an intense episode of massive star formation. We have characterized the properties of the starburst, which transformed 1.4 × 108 M⊙ of gas into stars around 5-6 Myr ago. The mechanical energy released by the central super stellar cluster (SSC), located in the core of the starburst, has created a cavity devoid of gas and dust around it, leaving a clean path through which the UV continuum of the SSC is observed, with almost no extinction. While the average extinction affecting the stellar continuum is significantly larger out of the cavity, with E(B - V) = 0.15 on average, we have not found any evidence for regions with very large extinctions, which could be hiding some young, massive stars not contributing to the global UV continuum. The observed soft and hard X-ray emissions are consistent with this scenario, being originated by the interstellar medium heated by

  9. Rationale for the luminal provision of butyrate in intestinal diseases.

    PubMed

    Wächtershäuser, A; Stein, J

    2000-08-01

    Short chain fatty acids (SCFA), especially butyrate, play central metabolic roles in maintaining the mucosal barrier in the gut. A lack of SCFA, leading to endogenous starvation of enterocytes, may be the cause of ulcerative colitis and other inflammatory conditions. The main source of SCFA is dietary fibre, but they can also be derived from structured lipids, e. g. tributyrin. Once absorbed by non-ionic diffusion or carrier-mediated anion exchanges, SCFA are either used locally as fuel for the enterocytes or enter the portal bloodstream. Butyrate has been shown to increase wound healing and to reduce inflammation in the small intestine. In the colon, butyrate is the dominant energy source for epithelial cells and affects cellular proliferation and differentiation by yet unknown mechanisms. Recent data suggest that the luminal provision of butyrate may be an appropriate means to improve wound healing in intestinal surgery and to ameliorate symptoms of inflammatory bowel diseases. PMID:11079736

  10. High resolution spectroscopy of the hot post-AGB stars IRAS 13266-5551 (CPD-55 5588) and IRAS 17311-4924 (Hen3-1428)

    NASA Astrophysics Data System (ADS)

    Sarkar, G.; Parthasarathy, M.; Reddy, B. E.

    2005-03-01

    High resolution spectra covering the wavelength range 4900 Å to 8250 Å of the hot post-AGB stars IRAS 13266-5551 (CPD-55 5588) and IRAS 17311-4924 (Hen3-1428) reveal absorption lines of C II, N II, O II, Al III, Si III and Fe III and a rich emission line spectrum consisting of H I, He I, C II, N I, O I, Mg II, Al II, Si II, V I, Mn I, Fe III, [Fe II] and [Cr II]. The presence of [N II] and [O I] lines and absence of [O III] indicate low excitation nebulae around these stars. The components of Na I absorption lines indicate the presence of neutral circumstellar envelopes in addition to the low excitation nebulae around these two hot post-AGB stars. The Hα lines show P-Cygni profiles indicating ongoing post-AGB mass loss. From the absorption lines we derived heliocentric radial velocities of 65.31 ± 0.34 km s-1 and 27.55 ± 0.74 km s-1 for IRAS 13266-5551 and IRAS 17311-4924 respectively. The high Galactic latitude and large radial velocity of IRAS 13266-5551 indicate that it belongs to the old disk population. Preliminary estimates for the CNO abundances in IRAS 13266-5551 are obtained. Based on observations made with the Victor M. Blanco 4m telescope of the Cerro Tololo Inter-American Observatory, Chile. Appendices and Tables [see full text], [see full text], [see full text] and [see full text] are only available in electronic form at http://www.edpsciences.org

  11. TIMASSS: the IRAS16293-2422 millimeter and submillimeter spectral survey: tentative detection of deuterated methyl formate (DCOOCH3)

    NASA Astrophysics Data System (ADS)

    Demyk, K.; Bottinelli, S.; Caux, E.; Vastel, C.; Ceccarelli, C.; Kahane, C.; Castets, A.

    2010-07-01

    Context. High deuterium fractionation is observed in various types of environments such as prestellar cores, hot cores, and hot corinos. It has proven to be an efficient probe for studying the physical and chemical conditions of these environments. The study of the deuteration of different molecules helps us to understand their formation. This is especially interesting for complex molecules like methanol and bigger molecules for which it may allow differentiation of gas-phase and solid-state formation pathways. Aims: Methanol exhibits a high deuterium fractionation in hot corinos. Since CH3OH is thought to be a precursor of methyl formate we expect that deuterated methyl formate is produced in such environments. We searched for the singly-deuterated isotopologue of methyl formate, DCOOCH3, in IRAS 16293-2422, a hot corino well-known for its high degree of methanol deuteration. Methods: We used the IRAM/JCMT unbiased spectral survey of IRAS 16293-2422, which allowed us to search for the DCOOCH3 rotational transitions within the survey spectral range (80-280 GHz, 328-366 GHz). The expected emission of deuterated methyl formate is modelled at LTE and compared with the observations. Results: We have tentatively detected DCOOCH3 in the protostar IRAS 16293-2422. We assign eight lines detected in the IRAM survey to DCOOCH3. Three of these lines are affected by blending problems, and one is affected by calibration uncertainties; nevertheless, the LTE emission model is compatible with the observations. A simple LTE modelling of the two cores in IRAS 16293-2422, based on a previous interferometric study of HCOOCH3, allows us to estimate the amount of DCOOCH3 in IRAS 16293-2422. Adopting an excitation temperature of 100 K and a source size of 2" and 1.5 arcsec for the A and B cores, respectively, we find that NA, DCOOCH3 = NB, DCOOCH3 ~ 6 × 1014 cm-2. The derived deuterium fractionation is ~15%, consistent with values for other deuterated species in this source and much

  12. Characteristics of estrogen-induced peroxidase in mouse uterine luminal fluid

    SciTech Connect

    Jellinck, P.H.; Newbold, R.R.; McLachlan, J.A. )

    1991-04-01

    Peroxidase activity in the uterine luminal fluid of mice treated with diethylstilbestrol was measured by the guaiacol assay and also by the formation of 3H2O from (2-3H)estradiol. In the radiometric assay, the generation of 3H2O and 3H-labeled water-soluble products was dependent on H2O2 (25 to 100 microM), with higher concentrations being inhibitory. Tyrosine or 2,4-dichlorophenol strongly enhanced the reaction catalyzed either by the luminal fluid peroxidase or the enzyme in the CaCl2 extract of the uterus, but decreased the formation of 3H2O from (2-3H)estradiol by lactoperoxidase in the presence of H2O2 (80 microM). NADPH, ascorbate, and cytochrome c inhibited both luminal fluid and uterine tissue peroxidase activity to the same extent, while superoxide dismutase showed a marginal activating effect. Lactoferrin, a major protein component of uterine luminal fluid, was shown not to contribute to its peroxidative activity, and such an effect by prostaglandin synthase was also ruled out. However, it was not possible to exclude eosinophil peroxidase, brought to the uterus after estrogen stimulation, as being the source of peroxidase activity in uterine luminal fluid.

  13. Feasibility analysis on integration of luminous environment measuring and design based on exposure curve calibration

    NASA Astrophysics Data System (ADS)

    Zou, Yuan; Shen, Tianxing

    2013-03-01

    Besides illumination calculating during architecture and luminous environment design, to provide more varieties of photometric data, the paper presents combining relation between luminous environment design and SM light environment measuring system, which contains a set of experiment devices including light information collecting and processing modules, and can offer us various types of photometric data. During the research process, we introduced a simulation method for calibration, which mainly includes rebuilding experiment scenes in 3ds Max Design, calibrating this computer aid design software in simulated environment under conditions of various typical light sources, and fitting the exposure curves of rendered images. As analytical research went on, the operation sequence and points for attention during the simulated calibration were concluded, connections between Mental Ray renderer and SM light environment measuring system were established as well. From the paper, valuable reference conception for coordination between luminous environment design and SM light environment measuring system was pointed out.

  14. Microstructure optimization of the composite phase ceramic phosphor for white LEDs with excellent luminous efficacy.

    PubMed

    Tang, Yan Ru; Zhou, Sheng Ming; Yi, Xue Zhuan; Lin, Hui; Zhang, Shuai; Hao, De Ming

    2015-12-01

    The two-phase MgAl2O4-Ce:YAG ceramic phosphor was fabricated by the solid-state reaction in vacuum, and it presented a better luminous efficacy than the single-phase transparent ceramic phosphor when directly combined with the blue light-emitting diodes. The addition of MgAl2O4 implemented the control of the grain sizes and the variation of microstructure, and the microstructure optimization further improved the luminous efficacy of the composite phase ceramic phosphor. A maximum luminous efficacy attaining 99 lm/W at the correlated color temperature 5000 K was obtained. The composite phase ceramic phosphor is expected to be a promising candidate for use in the high-power light source. PMID:26625030

  15. Faint CO Line Wings in Four Star-forming (Ultra)luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Leroy, Adam K.; Walter, Fabian; Decarli, Roberto; Bolatto, Alberto; Zschaechner, Laura; Weiss, Axel

    2015-09-01

    We report the results of a search for large velocity width, low-intensity line wings—a commonly used signature of molecular outflows—in four low redshift (ultra)luminous infrared galaxies that appear to be dominated by star formation. The targets were drawn from a sample of fourteen targets presented in Chung et al., who showed the stacked CO spectrum of the sample to exhibit 1000 km s-1-wide line wings. We obtained sensitive, wide bandwidth imaging of our targets using the IRAM Plateau de Bure Interferometer. We detect each target at very high significance but do not find the claimed line wings in these four targets. Instead, we constrain the flux in the line wings to be only a few percent. Casting our results as mass outflow rates following Cicone et al. we show them to be consistent with a picture in which very high mass loading factors preferentially occur in systems with high active galactic nucleus contributions to their bolometric luminosity. We identify one of our targets, IRAS 05083 (VII Zw 31), as a candidate molecular outflow.

  16. Structural Properties and Evidence for Interactions in a Sample of Luminous Blue Compact Galaxies

    NASA Astrophysics Data System (ADS)

    Newton, Cassidy L.; Fanelli, M.; Marcum, P.

    2010-01-01

    Understanding the life cycles of galaxies over cosmic time is a primary effort in modern astrophysics. Here we explore the nature of luminous blue compact galaxies (LBCGs), a class of galaxy in the local (z < 0.05) universe exhibiting blue optical colors [(B-V) < 0.5], high luminosity (MB < -19), one or more high surface brightness regions, and moderate to high star formation rates [> 5 M(sun) per year]. LBCGs appear to be similar in their global properties to the early evolutionary phases of most galaxies, but are more amenable to detailed analysis due to their low redshifts. We describe an ultraviolet and optical investigation of a sample of 50 LBCGs using UBVR & Hα imagery obtained at McDonald Observatory, ultraviolet photometry from GALEX, and correlative data from IRAS, 2MASS, and SDSS. Using these data, we explore the evolutionary state of LBCGs. In particular, we determine the radial and azimuthal light distributions, explore the spatial extent of ionized gas (e.g., centrally- concentrated versus spatially diffuse), compare multiwavelength measures of the high-mass star formation rate, and quantify the interaction strength using a variety of merger diagnostics. Although selected independent of their environment, most systems display either a close companion or the signature of an interaction such as tails, bridges, and possible polar rings. Interpretation of the assembly history of LBCGs provides insight on massive galaxy evolution at earlier epochs.

  17. MN48: a new Galactic bona fide luminous blue variable revealed by Spitzer and SALT

    NASA Astrophysics Data System (ADS)

    Kniazev, A. Y.; Gvaramadze, V. V.; Berdnikov, L. N.

    2016-07-01

    In this paper, we report the results of spectroscopic and photometric observations of the candidate evolved massive star MN48 disclosed via detection of a mid-infrared circular shell around it with the Spitzer Space Telescope. Follow-up optical spectroscopy of MN48 with the Southern African Large Telescope (SALT) carried out in 2011-2015 revealed significant changes in the spectrum of this star, which are typical of luminous blue variables (LBVs). The LBV status of MN48 was further supported by photometric monitoring which shows that in 2009-2011 this star has brightened by ≈0.9 and 1 mag in the V and Ic bands, respectively, then faded by ≈1.1 and 1.6 mag during the next four years, and apparently started to brighten again recently. The detected changes in the spectrum and brightness of MN48 make this star the 18th known Galactic bona fide LBV and increase the percentage of LBVs associated with circumstellar nebulae to more than 70 per cent. We discuss the possible birth place of MN48 and suggest that this star might have been ejected either from a putative star cluster embedded in the H II region IRAS 16455-4531 or the young massive star cluster Westerlund 1.

  18. Genomic Profiling in Luminal Breast Cancer

    PubMed Central

    Gluz, Oleg; Hofmann, Daniel; Würstlein, Rachel; Liedtke, Cornelia; Nitz, Ulrike; Harbeck, Nadia

    2013-01-01

    Summary The developments in gene expression analysis have made it possible to sub-classify hormone receptor-positive (luminal) breast cancer in different prognostic subgroups. This sub-classification is currently used in clinical routine as prognostic signature (e.g. 21-gene Onoctype DX®, 70-gene Mammaprint®). As yet, the optimal method for sub-classification has not been defined. Moreover, there is no evidence from prospective trials. This review explores widely used genomic signatures in luminal breast cancer, making a critical appraisal of evidence from retrospective/prospective trials. It is based on systematic literature search performed using Medline (accessed September 2013) and abstracts presented at the Annual Meeting of American Society of Clinical Oncology and San Antonio Breast Cancer Symposium. PMID:24550749

  19. Achromatic Emission Velocity Measurements in Luminous Flows

    NASA Technical Reports Server (NTRS)

    Schneider, S. J.; Fulghum, S. F.; Rostler, P. S.

    1997-01-01

    A new velocity measurement instrument for luminous flows was developed by Science Research Laboratory for NASA. The SIEVE (Segmented Image Emission VElocimeter) instrument uses broadband light emitted by the flow for the velocity measurement. This differs from other velocimetry techniques in that it does not depend on laser illumination and/or light scattering from particles in the flow. The SIEVE is a passive, non-intrusive diagnostic. By moving and adjusting the imaging optics, the SIEVE can provide three-dimensional mapping of a flow field and determine turbulence scale size. A SIEVE instrument was demonstrated on an illuminated rotating disk to evaluate instrument response and noise and on an oxy-acetylene torch to measure flame velocities. The luminous flow in rocket combustors and plumes is an ideal subject for the SIEVE velocity measurement technique.

  20. White LEDs with limit luminous efficacy

    NASA Astrophysics Data System (ADS)

    Lisitsyn, V. M.; Lukash, V. S.; Stepanov, S. A.; Yangyang, Ju

    2016-01-01

    In most promising widespread gallium nitride based LEDs emission is generated in the blue spectral region with a maximum at about 450 nm which is converted to visible light with the desired spectrum by means of phosphor. The thermal energy in the conversion is determined by the difference in the energies of excitation and emission quanta and the phosphor quantum yield. Heat losses manifest themselves as decrease in the luminous efficacy. LED heating significantly reduces its efficiency and life. In addition, while heating, the emission generation output and the efficiency of the emission conversion decrease. Therefore, the reduction of the energy losses caused by heating is crucial for LED development. In this paper, heat losses in phosphor-converted LEDs (hereinafter chips) during spectrum conversion are estimated. The limit values of the luminous efficacy for white LEDs are evaluated.

  1. Orbital masses of nearby luminous galaxies

    SciTech Connect

    Karachentsev, Igor D.; Kudrya, Yuri N. E-mail: yukudrya@gmail.com

    2014-09-01

    We use observational properties of galaxies accumulated in the Updated Nearby Galaxy Catalog to derive a dark matter mass of luminous galaxies via motions of their companions. The data on orbital-to-stellar mass ratio are presented for 15 luminous galaxies situated within 11 Mpc from us: the Milky Way, M31, M81, NGC 5128, IC342, NGC 253, NGC 4736, NGC 5236, NGC 6946, M101, NGC 4258, NGC 4594, NGC 3115, NGC 3627, and NGC 3368, as well as for a composite suite around other nearby galaxies of moderate and low luminosity. The typical ratio for these galaxies is M {sub orb}/M {sub *} = 31, corresponding to the mean local density of matter Ω {sub m} = 0.09, i.e., one-third of the global cosmic density. This quantity seems to be rather an upper limit of dark matter density, since the peripheric population of the suites may suffer from the presence of fictitious unbound members. We note that the Milky Way and M31 halos have lower dimensions and lower stellar masses than those of the other 13 nearby luminous galaxies. However, the dark-to-stellar mass ratio for both the Milky Way and M31 is typical for other neighboring luminous galaxies. The distortion in the Hubble flow, observed around the Local Group and five other neighboring groups, yields their total masses within the radius of a zero velocity surface, R {sub 0}; these masses are slightly lower than the orbital and virial values. This difference may be due to the effect of dark energy producing a kind of 'mass defect' within R {sub 0}.

  2. Luminal Conversion and Immunoregulation by Probiotics

    PubMed Central

    Ganesh, Bhanu Priya; Versalovic, James

    2015-01-01

    Beneficial microbes are responsible for the synthesis of nutrients and metabolites that are likely important for the maintenance of mammalian health. Many nutrients and metabolites derived from the gut microbiota by luminal conversion have been implicated in the development, homeostasis and function of innate and adaptive immunity. These factors clearly suggest that intestinal microbiota may influence host immunity via microbial metabolite-dependent mechanisms. We describe how intestinal microbes including probiotics generate microbial metabolites that modulate mucosal and systemic immunity. PMID:26617521

  3. Pulsations and outbursts of luminous blue variables

    SciTech Connect

    Cox, A.N.; Guzik, J.A.; Soukup, M.S.; Despain, K.M.

    1997-06-01

    We propose an outburst mechanism for the most luminous stars in our and other galaxies. These million solar luminosity stars, with masses (after earlier mass loss) of between 20 and maybe 70 solar masses, are pulsationally unstable for both radial and low-degree nonradial modes. Some of these modes are ``strange,`` meaning mostly that the pulsations are concentrated near the stellar surface and have very rapid growth rates in linear theory. The pulsation driving is by both the high iron line opacity (near 150,000 K) and the helium opacity (near 30,000 K) kappa effects. Periods range from 5 to 40 days. Depending on the composition, pulsations periodically produce luminosities above the Eddington limit for deep layers. The radiative luminosity creates an outward push that readily eases the very low gamma envelope to very large outburst radii. A key point is that a super-Eddington luminosity cannot be taken up by the sluggish convection rapidly enough to prevent an outward acceleration of much of the envelope. As the helium abundance in the envelope stellar material increases by ordinary wind mass loss and the luminous blue variable outbursts, the opacity in the deep pulsation driving layers decreases. This makes the current Eddington luminosity even higher so that pulsations can then no longer give radiative luminosities exceeding the limit. For the lower mass and luminosity luminous blue variables there is considerably less iron line opacity driving, and pulsations are almost all caused by the helium ionization kappa effect.

  4. X-Ray and Radio Observations of the Massive Star-forming Region IRAS 20126+4104

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    We present results from Chandra ACIS-I and Karl G. Jansky Very Large Array 6 cm continuum observations of the IRAS 20126+4104 massive star-forming region. We detect 150 X-ray sources within the 17‧ × 17‧ ACIS-I field, and a total of 13 radio sources within the 9.‧2 primary beam at 4.9 GHz. Among these observtions are the first 6 cm detections of the central sources reported by Hofner et al., namely, I20N1, I20S, and I20var. A new variable radio source is also reported. Searching the 2MASS archive, we identified 88 near-infrared (NIR) counterparts to the X-ray sources. Only four of the X-ray sources had 6 cm counterparts. Based on an NIR color-color analysis and on the Besançon simulation of Galactic stellar populations, we estimate that approximately 80 X-ray sources are associated with this massive star-forming region. We detect an increasing surface density of X-ray sources toward the massive protostar and infer the presence of a cluster of at least 43 young stellar objects within a distance of 1.2 pc from the massive protostar.

  5. A RECENT ACCRETION BURST IN THE LOW-MASS PROTOSTAR IRAS 15398-3359: ALMA IMAGING OF ITS RELATED CHEMISTRY

    SciTech Connect

    Jørgensen, Jes K.; Brinch, Christian; Lindberg, Johan E.; Bisschop, Suzanne E.; Visser, Ruud; Bergin, Edwin A.; Sakai, Nami; Yamamoto, Satoshi; Harsono, Daniel; Van Dishoeck, Ewine F.; Persson, Magnus V.

    2013-12-20

    Low-mass protostars have been suggested to show highly variable accretion rates throughout their evolution. Such changes in accretion, and related heating of their ambient envelopes, may trigger significant chemical variations on different spatial scales and from source-to-source. We present images of emission from C{sup 17}O, H{sup 13}CO{sup +}, CH{sub 3}OH, C{sup 34}S and C{sub 2}H toward the low-mass protostar IRAS 15398-3359 on 0.''5 (75 AU diameter) scales with the Atacama Large Millimeter/submillimeter Array at 340 GHz. The resolved images show that the emission from H{sup 13}CO{sup +} is only present in a ring-like structure with a radius of about 1-1.''5 (150-200 AU) whereas the CO and other high dipole moment molecules are centrally condensed toward the location of the central protostar. We propose that HCO{sup +} is destroyed by water vapor present on small scales. The origin of this water vapor is likely an accretion burst during the last 100-1000 yr increasing the luminosity of IRAS 15398-3359 by a factor of 100 above its current luminosity. Such a burst in luminosity can also explain the centrally condensed CH{sub 3}OH and extended warm carbon-chain chemistry observed in this source and furthermore be reflected in the relative faintness of its compact continuum emission compared to other protostars.

  6. Variability of the soft X-ray excess in IRAS 13224-3809

    NASA Astrophysics Data System (ADS)

    Kammoun, E.; Papadakis, I.; Sabra, B.

    2016-06-01

    We study the soft excess variability of the narrow line Seyfert 1 galaxy IRAS 13224-3809. We applied the `flux-flux plot' (FFP) method to the five archival XMM-Newton observations. We found that the FFPs are highly affected by the choice of the light curves' time bin size, due to the fast and large amplitude variations, and the intrinsic non-linear flux-flux relations in this source. We constructed FFPs in 11 energy bands below 1.7 keV, and considered the 1.7-3 keV band, as representative of the primary emission. The FFPs are well fitted by a `power-law plus a constant' model. The constants are positive in three out of five observations, consistent with zero in one observation, and negative below 1 keV in another. The best-fit slopes are flatter than unity at energies below ˜ 0.9 keV, suggesting the presence of intrinsic spectral variability. A power-law-like primary component, variable in flux and spectral slope (Γ∝ N_{PL}^{0.1}) and a soft-excess component, varying with the primary continuum (F_{excess}∝ F_{primary}^{0.46}), can explain the FFPs. In fact, this can create positive `constants', even when a stable spectral component does not exist. The negative and null constants, unexplainable by spectral variability, may signify the presence of an intrinsic variable, warm absorber.

  7. High Velocity Precessing Jet from the Water Fountain IRAS 18286-0959 Revealed by VLBA Observations

    NASA Astrophysics Data System (ADS)

    Yung, Bosco; Nakashima, J.; Imai, H.; Deguchi, S.; Diamond, P. J.; Kwok, S.

    2011-05-01

    We report the multi-epoch VLBA observations of 22.2GHz water maser emission associated with the "water fountain" star IRAS 18286-0959. The detected maser emission are distributed in the velocity range from -50km/s to 150km/s. The spatial distribution of over 70% of the identified maser features is found to be highly collimated along a spiral jet (namely, jet 1) extended from southeast to northwest direction, and the rest of the features appear to trace another spiral jet (jet 2) with a different orientation. The two jets form a "double-helix" pattern which lies across 200 milliarcseconds (mas). The maser features are reasonably fit by a model consisting of two precessing jets. The velocities of jet 1 and jet 2 are derived to be 138km/s and 99km/s, respectively. The precession period of jet 1 is about 56 years, and for jet 2 it is about 73 years. We propose that the appearance of two jets observed are the result of a single driving source with a significant proper motion. This research was supported by grants from the Research Grants Council of the Hong Kong Special Administrative Region, China, the Seed Funding Programme for Basic Research of the University of Hong Kong, Grant-in-Aid for Young Scientists from the Ministry 9 of Education, Culture, Sports, Science, and Technology, and Grant-in-Aid for Scientific Research from Japan Society for Promotion Science.

  8. Variability of the soft X-ray excess in IRAS 13224--3809

    NASA Astrophysics Data System (ADS)

    Kammoun, E.; Papadakis, I.; Sabra, B.

    2016-06-01

    We study the soft excess variability of the narrow line Seyfert 1 galaxy IRAS 13224-3809. We applied the `flux-flux plot' (FFP) method to the five archival XMM-Newton observations. We found that the FFPs are highly affected by the choice of the light curves' time bin size, due to the fast and large amplitude variations, and the intrinsic non-linear flux-flux relations in this source. We constructed FFPs in 11 energy bands below 1.7 keV, and considered the 1.7-3 keV band, as representative of the primary emission. The FFPs are well fitted by a `power-law plus a constant' model. The constants are positive in three out of five observations, consistent with zero in one observation, and negative below 1 keV in another. The best-fit slopes are flatter than unity at energies below ˜ 0.9 keV, suggesting the presence of intrinsic spectral variability. A power-law-like primary component, variable in flux and spectral slope (Γ∝ N_{PL}^{0.1}) and a soft-excess component, varying with the primary continuum (F_{excess}∝ F_{primary}^{0.46}), can explain the FFPs. In fact, this can create positive `constants', even when a stable spectral component does not exist. The negative and null constants, unexplainable by spectral variability, may signify the presence of an intrinsic variable, warm absorber.

  9. ROTATION OF THE NGC 1333 IRAS 4A2 PROTOSTELLAR JET

    SciTech Connect

    Choi, Minho; Kang, Miju; Tatematsu, Ken'ichi

    2011-02-20

    The bipolar jet of the NGC 1333 IRAS 4A2 protostar shows a velocity gradient in the direction perpendicular to the jet axis. This lateral velocity gradient can be seen throughout the jet imaged in a silicon monoxide line, 2500-8700 AU from the driving source, and is consistent with the rotation of the accretion disk. If this gradient is caused by the rotation of the jet around its axis, the average specific angular momentum is about 1.5 x 10{sup 21} cm{sup 2} s{sup -1}. Comparison of the kinematics between the jet and the disk suggests that the jet-launching region on the disk has a radius of about 2 AU, which supports the disk-wind models. The angular momentum transported away by the jet seems to be large enough for the protostar to accrete matter from the disk, confirming the crucial role of jets in the early phase of the star formation process.

  10. A spectrum-adjusted white organic light-emitting diode for the optimization of luminous efficiency and color rendering index

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Chen, Shu-ming

    2015-01-01

    High luminous efficiency and high color rendering index (CRI) are both the foremost factors for white organic light-emitting diodes (WOLEDs) to serve as next generation solid-state lighting sources. In this paper, we show that both luminous efficiency and CRI can be improved by adjusting the green/red spectra of WOLEDs. With green emission spectra matching with the human photopic curve, the WOLEDs exhibit higher luminous efficiency and higher CRI. Theoretical calculation shows that by tuning the white emission spectra to maximally match with the human photopic curve, the luminous efficiency can be improved by 41.8% without altering the color coordinates, the color correlated temperature (CCT) and the external quantum efficiency (EQE) of the WOLEDs.

  11. Therapy of acute wounds with water-filtered infrared-A (wIRA)

    PubMed Central

    Hartel, Mark; Illing, Peter; Mercer, James B.; Lademann, Jürgen; Daeschlein, Georg; Hoffmann, Gerd

    2007-01-01

    Water-filtered infrared-A (wIRA) as a special form of heat radiation with a high tissue penetration and with a low thermal load to the skin surface acts both by thermal and thermic as well as by non-thermal and non-thermic effects. wIRA produces a therapeutically usable field of heat in the tissue and increases tissue temperature, tissue oxygen partial pressure, and tissue perfusion. These three factors are decisive for a sufficient tissue supply with energy and oxygen and consequently as well for wound healing and infection defense. wIRA can considerably alleviate the pain (with remarkably less need for analgesics) and diminish an elevated wound exudation and inflammation and can show positive immunomodulatory effects. wIRA can advance wound healing or improve an impaired wound healing both in acute and in chronic wounds including infected wounds. Even the normal wound healing process can be improved. A prospective, randomized, controlled, double-blind study with 111 patients after major abdominal surgery at the University Hospital Heidelberg, Germany, showed with 20 minutes irradiation twice a day (starting on the second postoperative day) in the group with wIRA and visible light VIS (wIRA(+VIS), approximately 75% wIRA, 25% VIS) compared to a control group with only VIS a significant and relevant pain reduction combined with a markedly decreased required dose of analgesics: during 230 single irradiations with wIRA(+VIS) the pain decreased without any exception (median of decrease of pain on postoperative days 2-6 was 13.4 on a 100 mm visual analog scale VAS 0-100), while pain remained unchanged in the control group (p<0.001). The required dose of analgesics was 57-70% lower in the subgroups with wIRA(+VIS) compared to the control subgroups with only VIS (median 598 versus 1398 ml ropivacaine, p<0.001, for peridural catheter analgesia; 31 versus 102 mg piritramide, p=0.001, for patient-controlled analgesia; 3.4 versus 10.2 g metamizole, p=0.005, for intravenous

  12. Therapy of acute wounds with water-filtered infrared-A (wIRA).

    PubMed

    Hartel, Mark; Illing, Peter; Mercer, James B; Lademann, Jürgen; Daeschlein, Georg; Hoffmann, Gerd

    2007-01-01

    Water-filtered infrared-A (wIRA) as a special form of heat radiation with a high tissue penetration and with a low thermal load to the skin surface acts both by thermal and thermic as well as by non-thermal and non-thermic effects. wIRA produces a therapeutically usable field of heat in the tissue and increases tissue temperature, tissue oxygen partial pressure, and tissue perfusion. These three factors are decisive for a sufficient tissue supply with energy and oxygen and consequently as well for wound healing and infection defense. wIRA can considerably alleviate the pain (with remarkably less need for analgesics) and diminish an elevated wound exudation and inflammation and can show positive immunomodulatory effects. wIRA can advance wound healing or improve an impaired wound healing both in acute and in chronic wounds including infected wounds. Even the normal wound healing process can be improved.A prospective, randomized, controlled, double-blind study with 111 patients after major abdominal surgery at the University Hospital Heidelberg, Germany, showed with 20 minutes irradiation twice a day (starting on the second postoperative day) in the group with wIRA and visible light VIS (wIRA(+VIS), approximately 75% wIRA, 25% VIS) compared to a control group with only VIS a significant and relevant pain reduction combined with a markedly decreased required dose of analgesics: during 230 single irradiations with wIRA(+VIS) the pain decreased without any exception (median of decrease of pain on postoperative days 2-6 was 13.4 on a 100 mm visual analog scale VAS 0-100), while pain remained unchanged in the control group (p<0.001). The required dose of analgesics was 57-70% lower in the subgroups with wIRA(+VIS) compared to the control subgroups with only VIS (median 598 versus 1398 ml ropivacaine, p<0.001, for peridural catheter analgesia; 31 versus 102 mg piritramide, p=0.001, for patient-controlled analgesia; 3.4 versus 10.2 g metamizole, p=0.005, for intravenous and

  13. The preferentially magnified active nucleus in IRAS F10214+4724 - III. VLBI observations of the radio core

    NASA Astrophysics Data System (ADS)

    Deane, R. P.; Rawlings, S.; Garrett, M. A.; Heywood, I.; Jarvis, M. J.; Klöckner, H.-R.; Marshall, P. J.; McKean, J. P.

    2013-10-01

    We report 1.7 GHz very long baseline interferometry (VLBI) observations of IRAS F10214+4724, a lensed z = 2.3 obscured quasar with prodigious star formation. We detect what we argue to be the obscured active nucleus with an effective angular resolution of <50 pc at z = 2.3. The S1.7 = 210 μJy (9σ) detection of this unresolved source is located within the Hubble Space Telescope rest-frame ultraviolet/optical arc, however, ≳100 mas northwards of the arc centre of curvature. This leads to a source-plane inversion that places the European VLBI Network detection to within milliarcseconds of the modelled cusp caustic, resulting in a very large magnification (μ ˜70), over an order of magnitude larger than the CO (1→0) derived magnification of a spatially resolved Jansky Very Large Array (JVLA) map, using the same lens model. We estimate the quasar bolometric luminosity from a number of independent techniques and with our X-ray modelling find evidence that the AGN may be close to Compton thick, with an intrinsic bolometric luminosity of log10(/L⊙) = 11.34 ± 0.27 dex. We make the first black hole mass estimate of IRAS F10214+4724 and find log10(MBH/M⊙) = 8.36 ± 0.56 which suggests a low black hole accretion rate (λ = dot{M} / dot{M}_Edd ˜ 3± ^7_2 per cent). We find evidence for an MBH/Mspheroid ratio that is one to two orders of magnitude larger than that of submillimetre galaxies (SMGs) at z ˜ 2. At face value, this suggests that IRAS F10214+4724 has undergone a different evolutionary path compared to SMGs at the same epoch. A primary result of this work is the demonstration that emission regions of different sizes and positions can undergo significantly different magnification boosts (>1 dex) and therefore distort our view of high-redshift, gravitationally lensed galaxies.

  14. A HERSCHEL SURVEY OF THE [N II] 205 {mu}m LINE IN LOCAL LUMINOUS INFRARED GALAXIES: THE [N II] 205 {mu}m EMISSION AS A STAR FORMATION RATE INDICATOR

    SciTech Connect

    Zhao Yinghe; Gao Yu; Lu, Nanyao; Xu, C. Kevin; Lord, S.; Howell, J.; Appleton, P.; Mazzarella, J.; Schulz, B.; Isaak, K. G.; Charmandaris, V.; Diaz-Santos, T.; Surace, J.; Evans, A.; Iwasawa, K.; Leech, J.; Petric, A. O.; Sanders, D. B.; Van der Werf, P. P.

    2013-03-01

    We present, for the first time, a statistical study of [N II] 205 {mu}m line emission for a large sample of local luminous infrared galaxies using Herschel Spectral and Photometric Imaging Receiver Fourier Transform Spectrometer (SPIRE FTS) data. For our sample of galaxies, we investigate the correlation between the [N II] luminosity (L{sub [N{sub II]}}) and the total infrared luminosity (L{sub IR}), as well as the dependence of L{sub [N{sub II]}}/L{sub IR} ratio on L{sub IR}, far-infrared colors (IRAS f{sub 60}/f{sub 100}), and the [O III] 88 {mu}m to [N II] luminosity ratio. We find that L{sub [N{sub II]}} correlates almost linearly with L{sub IR} for non-active galactic nucleus galaxies (all having L{sub IR} < 10{sup 12} L{sub Sun }) in our sample, which implies that L{sub [N{sub II]}} can serve as a star formation rate tracer which is particularly useful for high-redshift galaxies that will be observed with forthcoming submillimeter spectroscopic facilities such as the Atacama Large Millimeter/submillimeter Array. Our analysis shows that the deviation from the mean L{sub [N{sub II]}}-L{sub IR} relation correlates with tracers of the ionization parameter, which suggests that the scatter in this relation is mainly due to the variations in the hardness, and/or ionization parameter, of the ambient galactic UV field among the sources in our sample.

  15. IRAS observations of the Pluto-Charon system

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    High-signal-to-noise-ratio observations of the Pluto-Charon system at 25, 60, and 100 microns using IRAS are combined with visual-magnitude and mutual-eclipse constraints to evaluate thermal models of Pluto and Charon. These models are consistent with eclipse observation by Dunbar and Tedesco (1986) but not with Reinsch and Pakull (1987). The most likely model for Charon is the standard asteroid model, typical for the icy Galilean and Saturnian satellites. Charon models with a significant atmosphere can be ruled out. Based on currently available radius and albedo constraints, no significant numerical distinction is possible between Pluto models ranging from isothermal spheres with surface emissivity between 0.4 and 0.9. Concerns regarding the viability of an emissivity as low as 0.4 favor the higher-emissivity models. The globally uniform surface temperature of Pluto may thus at present be as low as 45 K, with a methane column abundance of 6.7 cm atm. The most likely models are centered on radii of 1180 and 747 km and albedos of 0.47 and 0.26 for Pluto and Charon, respectively.

  16. IRAS observations of the Pluto-Charon system

    SciTech Connect

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

    1987-10-01

    High-signal-to-noise-ratio observations of the Pluto-Charon system at 25, 60, and 100 microns using IRAS are combined with visual-magnitude and mutual-eclipse constraints to evaluate thermal models of Pluto and Charon. These models are consistent with eclipse observation by Dunbar and Tedesco (1986) but not with Reinsch and Pakull (1987). The most likely model for Charon is the standard asteroid model, typical for the icy Galilean and Saturnian satellites. Charon models with a significant atmosphere can be ruled out. Based on currently available radius and albedo constraints, no significant numerical distinction is possible between Pluto models ranging from isothermal spheres with surface emissivity between 0.4 and 0.9. Concerns regarding the viability of an emissivity as low as 0.4 favor the higher-emissivity models. The globally uniform surface temperature of Pluto may thus at present be as low as 45 K, with a methane column abundance of 6.7 cm atm. The most likely models are centered on radii of 1180 and 747 km and albedos of 0.47 and 0.26 for Pluto and Charon, respectively. 21 references.

  17. Image construction from the IRAS survey and data fusion

    NASA Technical Reports Server (NTRS)

    Bontekoe, Tj. R.

    1990-01-01

    The IRAS survey data can be used successfully to produce images of extended objects. The major difficulty, viz. non-uniform sampling, different response functions for each detector, and varying signal-to-noise levels for each detector for each scan, were resolved. The results of three different image construction techniques are compared: co-addition, constrained least squares, and maximum entropy. The maximum entropy result is superior. An image of the galaxy M51 with an average spatial resolution of 45 arc seconds, is presented using 60 micron survey data. This exceeds the telescope diffraction limit of 1 minute of arc, at this wavelength. Data fusion is a proposed method for combining data from different instruments, with different spatial resolutions, at different wavelengths. Direct estimates of the physical parameters, temperature, density and composition, can be made from the data without prior images (re-)construction. An increase in the accuracy of these parameters is expected as the result of this more systematic approach.

  18. It's about time: Presentation in honor of Ira Hirsh

    NASA Astrophysics Data System (ADS)

    Grant, Ken

    2002-05-01

    Over his long and illustrious career, Ira Hirsh has returned time and time again to his interest in the temporal aspects of pattern perception. Although Hirsh has studied and published articles and books pertaining to many aspects of the auditory system, such as sound conduction in the ear, cochlear mechanics, masking, auditory localization, psychoacoustic behavior in animals, speech perception, medical and audiological applications, coupling between psychophysics and physiology, and ecological acoustics, it is his work on auditory timing of simple and complex rhythmic patterns, the backbone of speech and music, that are at the heart of his more recent work. Here, we will focus on several aspects of temporal processing of simple and complex signals, both within and across sensory systems. Data will be reviewed on temporal order judgments of simple tones, and simultaneity judgments and intelligibility of unimodal and bimodal complex stimuli where stimulus components are presented either synchronously or asynchronously. Differences in the symmetry and shape of ``temporal windows'' derived from these data sets will be highlighted.

  19. The large-scale morphology of IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Babul, Arif; Starkman, Glenn D.; Strauss, Michael A.

    1993-01-01

    At present, visual inspection is the only method for comparing the large-scale morphologies in the distribution of galaxies to those in model universes generated by N-body simulations. To remedy the situation, we have developed a set of three structure functions (S1, S2, S3) that quantify the degree of large-scale prolateness, oblateness, and sphericity/uniformity of a 3-D particle distribution and have applied them to a volume-limited (less than = 4000 km/s) sample of 699 IRAS galaxies with f sub 60 greater than 1.2 Jy. To determine the structure functions, we randomly select 500 galaxies as origins of spherical windows of radius R sub w, locate the centroid of the galaxies in the window (assuming all galaxies have equal mass) and then, compute the principal moments of inertia (I sub 1, I sub 2, I sub 3) about the centroid. Each S sub i is a function of (I sub 2)/(I sub 1) and (I sub 3)/I sub 1). S1, S2, and S3 tend to unity for highly prolate, oblate, and uniform distributions, respectively and tend to zero otherwise. The resulting 500 values of S sub i at each scale R sub w are used to construct a histogram.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  1. NIST traceable measurements of radiance and luminance levels of night-vision-goggle test-instruments

    NASA Astrophysics Data System (ADS)

    Eppeldauer, G. P.; Podobedov, V. B.

    2014-05-01

    In order to perform radiance and luminance level measurements of night-vision-goggle (NVG) test instruments, NIST developed new-generation transfer-standard radiometers (TR). The new TRs can perform low-level radiance and luminance measurements with SI traceability and low uncertainty. The TRs were calibrated against NIST detector/radiometer standards holding the NIST photometric and radiometric scales. An 815 nm diode laser was used at NIST for the radiance responsivity calibrations. A spectrally flat (constant) filter correction was made for the TRs to correct the spectral responsivity change of the built-in Si photodiode for LEDs peaking at different wavelengths in the different test sets. The radiance responsivity transfer to the test instruments (test-sets) is discussed. The radiance values of the test instruments were measured with the TRs. The TRs propagate the traceablity to the NIST detector-based reference scales. The radiance uncertainty obtained from three TR measurements was 4.6 % (𝑘=2) at a luminance of 3.43 x 10-4 cd/m2. The output radiance of the previously used IR sphere source and the radiance responsivity of a previously used secondary standard detector unit, which was originally calibrated against an IR sphere source, were also measured with the TRs. The performances of the NVG test instruments were evaluated and the manufacturer produced radiance and luminance levels were calibrated with SI/NIST traceability.

  2. Characterization of butyrate transport across the luminal membranes of equine large intestine.

    PubMed

    Nedjadi, Taoufik; Moran, Andrew W; Al-Rammahi, Miran A; Shirazi-Beechey, Soraya P

    2014-10-01

    The diet of the horse, pasture forage (grass), is fermented by the equine colonic microbiota to short-chain fatty acids, notably acetate, propionate and butyrate. Short-chain fatty acids provide a major source of energy for the horse and contribute to many vital physiological processes. We aimed to determine both the mechanism of butyrate uptake across the luminal membrane of equine colon and the nature of the protein involved. To this end, we isolated equine colonic luminal membrane vesicles. The abundance and activity of cysteine-sensitive alkaline phosphatase and villin, intestinal luminal membrane markers, were significantly enriched in membrane vesicles compared with the original homogenates. In contrast, the abundance of GLUT2 protein and the activity of Na(+)-K(+)-ATPase, known markers of the intestinal basolateral membrane, were hardly detectable. We demonstrated, by immunohistochemistry, that monocarboxylate transporter 1 (MCT1) protein is expressed on the luminal membrane of equine colonocytes. We showed that butyrate transport into luminal membrane vesicles is energized by a pH gradient (out < in) and is not Na(+) dependent. Moreover, butyrate uptake is time and concentration dependent, with a Michaelis-Menten constant of 5.6 ± 0.45 mm and maximal velocity of 614 ± 55 pmol s(-1) (mg protein)(-1). Butyrate transport is significantly inhibited by p-chloromercuribenzoate, phloretin and α-cyano-4-hydroxycinnamic acid, all potent inhibitors of MCT1. Moreover, acetate and propionate, as well as the monocarboxylates pyruvate and lactate, also inhibit butyrate uptake. Data presented here support the conclusion that transport of butyrate across the equine colonic luminal membrane is predominantly accomplished by MCT1. PMID:25172888

  3. Luminal B breast cancer subtype displays a dicotomic epigenetic pattern.

    PubMed

    Bediaga, Naiara G; Beristain, Elena; Calvo, Borja; Viguri, María A; Gutierrez-Corres, Borja; Rezola, Ricardo; Ruiz-Diaz, Irune; Guerra, Isabel; de Pancorbo, Marian M

    2016-01-01

    Luminal B breast tumors have aggressive clinical and biological features, and constitute the most heterogeneous molecular subtype, both clinically and molecularly. Unfortunately, the immunohistochemistry correlate of the luminal B subtype remains still imprecise, and it has now become of paramount importance to define a classification scheme capable of segregating luminal tumors into clinically meaningful subgroups that may be used clinically to guide patient management. With the aim of unraveling the DNA methylation profiles of the luminal subtypes currently being most used in the clinical setting, we have quantified the DNA methylation level of 27,578 CpG sites in 17 luminal B (ER+, Ki67 ≥ 20 % or PgR < 20 % and HER2-), 8 luminal A (ER+ and Ki67 > 20 %) and 4 luminal B-HER2+ (ER+ and HER2+) breast cancer samples by using the Illumina Infinium methylation microarray approach. Unsupervised hierarchical clustering revealed that DNA methylation stratifies luminal B samples in two categories with differing epigenetic and clinical features. One subgroup of luminal B samples showed a methylator phenotype and clustered with the lumB-HER tumors, while the other showed less methylated events, clustered with the luminal A. A 3 CpG marker panel capable of discriminating methylator versus non-methylator luminal B samples was identified and further validated in an independent cohort of patients. Our results provide evidence that DNA methylation and, more specifically, a panel of 3 CpG markers, enables the stratification of luminal B samples in two categories with differing epigenetic and clinical features and support the utilization of this panel for therapeutic stratification of patients with luminal breast cancer. PMID:27330889

  4. Connecting low- and high-mass star formation: the intermediate-mass protostar IRAS 05373+2349 VLA 2

    NASA Astrophysics Data System (ADS)

    Brown, G. M.; Johnston, K. G.; Hoare, M. G.; Lumsden, S. L.

    2016-08-01

    Until recently, there have been few studies of the protostellar evolution of intermediate-mass (IM) stars, which may bridge the low-and high-mass regimes. This paper aims to investigate whether the properties of an IM protostar within the IRAS 05373+2349 embedded cluster are similar to that of low- and/or high-mass protostars. We carried out Very Large Array as well as Combined Array for Research in Millimeter Astronomy continuum and 12CO(J=1-0) observations, which uncover seven radio continuum sources (VLA 1-7). The spectral index of VLA 2, associated with the IM protostar is consistent with an ionised stellar wind or jet. The source VLA 3 is coincident with previously observed H2 emission line objects aligned in the north-south direction (P.A. -20 to -12°), which may be either an ionised jet emanating from VLA 2 or (shock-)ionised cavity walls in the large-scale outflow from VLA 2. The position angle between VLA 2 and 3 is slightly misaligned with the large-scale outflow we map at ˜5-arcsec resolution in 12CO (P.A. ˜30°), which in the case of a jet suggests precession. The emission from the mm core associated with VLA 2 is also detected; we estimate its mass to be 12-23 M⊙, depending on the contribution from ionised gas. Furthermore, the large-scale outflow has properties intermediate between outflows from low- and high-mass young stars. Therefore, we conclude that the IM protostar within IRAS 05373+2349 is phenomenologically as well as quantitatively intermediate between the low- and high-mass domains.

  5. Therapy of chronic wounds with water-filtered infrared-A (wIRA)

    PubMed Central

    von Felbert, Verena; Schumann, Hauke; Mercer, James B.; Strasser, Wolfgang; Daeschlein, Georg; Hoffmann, Gerd

    2008-01-01

    The central portion of chronic wounds is often hypoxic and relatively hypothermic, representing a deficient energy supply of the tissue, which impedes wound healing or even makes it impossible. Water-filtered infrared-A (wIRA) is a special form of heat radiation with a high tissue penetration and a low thermal load to the skin surface. wIRA produces a therapeutically usable field of heat and increases temperature, oxygen partial pressure and perfusion of the tissue. These three factors are decisive for a sufficient tissue supply with energy and oxygen and consequently as well for wound healing, especially in chronic wounds, and infection defense. wIRA acts both by thermal and thermic as well as by non-thermal and non-thermic effects. wIRA can advance wound healing or improve an impaired wound healing process and can especially enable wound healing in non-healing chronic wounds. wIRA can considerably alleviate the pain and diminish wound exudation and inflammation and can show positive immunomodulatory effects. In a prospective, randomized, controlled study of 40 patients with chronic venous stasis ulcers of the lower legs irradiation with wIRA and visible light (VIS) accelerated the wound healing process (on average 18 vs. 42 days until complete wound closure, residual ulcer area after 42 days 0.4 cm² vs. 2.8 cm²) and led to a reduction of the required dose of pain medication in comparison to the control group of patients treated with the same standard care (wound cleansing, wound dressing with antibacterial gauze, and compression garment therapy) without the concomitant irradiation. Another prospective study of 10 patients with non-healing chronic venous stasis ulcers of the lower legs included extensive thermographic investigation. Therapy with wIRA(+VIS) resulted in a complete or almost complete wound healing in 7 patients and a marked reduction of the ulcer size in another 2 of the 10 patients, a clear reduction of pain and required dose of pain medication

  6. Water-filtered infrared-A (wIRA) in acute and chronic wounds

    PubMed Central

    Hoffmann, Gerd

    2009-01-01

    Water-filtered infrared-A (wIRA), as a special form of heat radiation with a high tissue penetration and a low thermal load to the skin surface, can improve the healing of acute and chronic wounds both by thermal and thermic as well as by non-thermal and non-thermic effects. wIRA increases tissue temperature (+2.7°C at a tissue depth of 2 cm), tissue oxygen partial pressure (+32% at a tissue depth of 2 cm) and tissue perfusion. These three factors are decisive for a sufficient supply of tissue with energy and oxygen and consequently also for wound healing and infection defense. wIRA can considerably alleviate pain (without any exception during 230 irradiations) with substantially less need for analgesics (52–69% less in the groups with wIRA compared to the control groups). It also diminishes exudation and inflammation and can show positive immunomodulatory effects. The overall evaluation of the effect of irradiation as well as the wound healing and the cosmetic result (assessed on visual analogue scales) were markedly better in the group with wIRA compared to the control group. wIRA can advance wound healing (median reduction of wound size of 90% in severely burned children already after 9 days in the group with wIRA compared to 13 days in the control group; on average 18 versus 42 days until complete wound closure in chronic venous stasis ulcers) or improve an impaired wound healing (reaching wound closure and normalization of the thermographic image in otherwise recalcitrant chronic venous stasis ulcers) both in acute and in chronic wounds including infected wounds. After major abdominal surgery there was a trend in favor of the wIRA group to a lower rate of total wound infections (7% versus 15%) including late infections following discharge from hospital (0% versus 8%) and a trend towards a shorter postoperative hospital stay (9 versus 11 days). Even the normal wound healing process can be improved. The mentioned effects have been proven in six prospective

  7. Nonlinear Pulsation Modeling of Luminous Blue Variables

    SciTech Connect

    Despain, Kate M.; Guzik, Joyce A.; Cox, Arthur N.

    1997-12-31

    Using an updated version of the Ostlie and Cox (1993) nonlinear hydrodynamics code, we show the results of Luminous Blue Variable (LBV) envelope models based on evolution models of initial mass 50-80 M solar. including mass loss. The models use OPAL opacities, contain 60-120 Lagrangian zones, include time dependent convection, and are given an initial photospheric radial velocity amplitude of 1 km/sec. Our goal is to explain the reason for the LBV instability strip and suggest a cause for LBV outbursts observed in massive stars in our Galaxy as well as the LMC and SMC.

  8. Luminous variables in the Quintuplet cluster

    NASA Astrophysics Data System (ADS)

    Glass, I. S.; Matsumoto, S.; Carter, B. S.; Sekiguchi, K.

    1999-03-01

    We report observations of variability amongst the stars of the `Quintuplet' cluster located about 30 pc in projection from the centre of the Galaxy. Two of the five cocoon star members, which may be protostars or peculiar Wolf-Rayet stars, are seen to vary slowly with moderate amplitude (0.4-0.5 mag). The bright star within the `Pistol' H ii region, suspected of being a luminous blue variable (LBV), has in fact been found to show variability, confirming its tentative classification. A second nearby presumed LBV also varies. One of the apparent Quintuplet members is likely to be a Mira variable along the same line of sight.

  9. Outflows Driven by a Potential Proto-Brown Dwarf Binary System IRAS 16253-2429

    NASA Astrophysics Data System (ADS)

    Hsieh, Tien-Hao; Lai, Shih-Ping; Belloche, Arnaud; Wyrowski, Friedrich

    2015-08-01

    We have studied the molecular outflows driven by a potential proto-brown dwarf candidate IRAS 16253-2429 (hereafter IRAS 16253) with CO (2—1) using SMA and IRAM 30m telescope and CO (6—5) using APEX. Our SMA observations suggest that IRAS 16253 is hosting a binary system. The low mass of its envelope suggests that the central objects may eventually accrete only ~0.14 Msun of material (assuming the star formation efficiency is at most 0.3), which makes IRAS 16253 a potential proto brown dwarf binary system since the maximum mass of a brown dwarf is 0.08 Msun; one or two brown dwarfs may form depending on the current mass of the protostars and the future accretion process. The Position-Velocity diagrams of the outflows show sinusoidal structures which may be related to the outflow wiggling from the binary rotation. This allowed us to estimate the orbital period of the binary system. On the basis of Kepler's third law, we suggest that IRAS 16253 is very likely to contain at least one proto brown dwarf if the binary separation is less than ~0.5 arcsec. The large-scale outflows are further mapped with IRAM 30m telescope and APEX Champ+. We found that CO (6—5) traces high-excited gas around the precessing H2 jets and CO (2—1) likely probes the cold swept-up gas or entrained gas with cone-like structure.

  10. Peripheral visual response time and retinal luminance-area relations

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1975-01-01

    Experiments were undertaken to elucidate the stimulus luminance-retinal area relationship that underlies response time (RT) behavior. Mean RT was significantly faster to stimuli imaged beyond about 70 deg of arc from the fovea when their luminance was increased by an amount equal to the foveal stimulus luminance multiplied by the cosine of the angle between the peripheral stimuli and the line of sight. This and additional data are discussed in relation to previous psychophysical data and to possible response mechanisms.

  11. Dust around Mira variables: An analysis of IRAS LRS spectra

    NASA Technical Reports Server (NTRS)

    Slijkhuis, S.

    1989-01-01

    The spatial extent and spectral appearance of the thin dust shell around Mira variables is determined largely by the dust absorptivity, Q(sub abs)(lambda), and the dust condensation temperature T(sub cond). Both Q(sub abs)(lambda) and T(sub cond) are extracted from IRAS low-resolution spectra (LRS) spectra. In order to do this, the assumption that the ratio of total power in the 10 micron feature to that in the 20 micron feature should be equal to that measured in other amorphous silicates (e.g., synthesized amorphous Mg2SiO4). It was found that T(sub cond) decreases with decreasing strength of the 10 micron feature, from T(sub cond) = 1000 K to 500 K (estimated error 20 percent). A value for the near-infrared dust absorptivity could not be determined. Although this parameter strongly affects the condensation radius, it hardly affects the shape of the LRS spectrum (as long as the optically thin approximation is valid), because it scales the spatial distribution of the dust. Information on the magnitude of the near-infrared dust absorptivity may be deduced from the unique carbon star BM Gem. This star has a LRS spectrum with silicate features indication an inner dust shell temperature of at least 1000 K. However, on the basis of observations in the 1920s-30s one may infer an inner dust shell radius of at least 6x10(exp 12)m. To have this high temperature at such a large distance, the near-infrared absorptivity of the dust must be high.

  12. CH in absorption in IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Bottinelli, S.; Wakelam, V.; Caux, E.; Vastel, C.; Aikawa, Y.; Ceccarelli, C.

    2014-07-01

    While recent studies of the solar-mass protostar IRAS 16293-2422 have focused on its inner arcsecond, the wealth of Herschel/Heterodyne Instrument for the Far-Infrared (HIFI) data has shown that the structure of the outer envelope and of the transition region to the more diffuse interstellar medium is not clearly constrained. We use rotational ground-state transitions of CH (methylidyne), as a tracer of the lower density envelope. Assuming local thermodynamic equilibrium, we perform a χ2 minimization of the high spectral resolution HIFI observations of the CH transitions at ˜532 and ˜536 GHz in order to derive column densities in the envelope and in the foreground cloud. We obtain column densities of (7.7 ± 0.2) × 1013 cm-2 and (1.5 ± 0.3) × 1013 cm-2, respectively. The chemical modelling predicts column densities of (0.5 - 2) × 1013 cm-2 in the envelope (depending on the cosmic ray ionization rate), and 5 × 1011 to 2.5 × 1014 cm-2 in the foreground cloud (depending on time). Both observed abundances are reproduced by the model at a satisfactory level. The constraints set by these observations on the physical conditions in the foreground cloud are however weak. Furthermore, the CH abundance in the envelope is strongly affected by the rate coefficient of the reaction H+CH→C+H2; further investigation of its value at low temperature would be necessary to facilitate the comparison between the model and the observations.

  13. Luminous Stars in Galaxies Beyond 3 Mpc

    NASA Astrophysics Data System (ADS)

    Whitmore, B. C.; Wfc3 Science Oversight Committee

    2011-06-01

    I am mainly interested in the formation and destruction of young star clusters in nearby star forming galaxies such as the Antennae, M83, and M51. One of the first analysis steps is to throw out all those pesky stars that keep contaminating my young cluster samples. Recently, spurred on by our new Wide Field Camera 3 (WFC3) Early Release Science data of galaxies including M83, NGC 4214, M82, NGC 2841, and Cen A, we began taking a closer look at the stellar component. Questions we are addressing are: 1) what are the most luminous stars, 2) how can we use them to help study the destruction of star clusters and the population of the field, 3) what fraction of stars, at least the bright stars, are formed in the field, in associations, and in compact clusters. In this contribution we describe some of the beginning steps in this process. More specifically, we describe how we separate stars from clusters in our galaxies, and describe how candidate Luminous Blue Variables (LBVs) and "Single Star" HII (SSHII) regions have been identified.

  14. Night vision goggle luminance disparity and the Pulfrich phenomenon

    NASA Astrophysics Data System (ADS)

    Pinkus, Alan; Task, Harry L.

    2004-09-01

    When night vision goggle (NVG) image intensifier tubes (I2Ts) are replaced during maintenance, the output luminances of the two channels must not exceed a ratio of 1.5 (brighter channel luminance divided by the dimmer channel luminance) in order to meet the current allowed binocular luminance disparity specification. Two studies were performed to investigate the validity of this requirement. The first study estimated thresholds of binocular luminance disparity detection for observers looking through NVGs. For eight observers, the 25% corrected-for-chance probability of detecting an ocular luminance difference, yielded an average ratio of 1.43 indicating that the current 1.5 specification is perhaps too loose. The second study investigated the Pulfrich phenomenon, a pseudo-stereo effect that can be induced by presenting luminance imbalances to the eyes. This study created NVG luminance imbalances using neutral density (ND) filters and then investigated whether or not the various imbalance levels were sufficient to cause the Pulfrich phenomenon to be perceived. Results indicated an imbalance ratio of 1.10 was insufficient to cause the effect to be seen, but a ratio of 1.26 was sufficient (p <= 0.0003) for the effect to be seen, at least part of the time. Based on these results, it is apparent the allowed binocular luminance disparity ratio should probably be tightened to at least 1.3 with a goal of 1.2.

  15. Luminance-model-based DCT quantization for color image compression

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Peterson, Heidi A.

    1992-01-01

    A model is developed to approximate visibility thresholds for discrete cosine transform (DCT) coefficient quantization error based on the peak-to-peak luminance of the error image. Experimentally measured visibility thresholds for R, G, and B DCT basis functions can be predicted by a simple luminance-based detection model. This model allows DCT coefficient quantization matrices to be designed for display conditions other than those of the experimental measurements: other display luminances, other veiling luminances, and other spatial frequencies (different pixel spacings, viewing distances, and aspect ratios).

  16. The effect of radiation on the IRAS all-sky survey

    NASA Technical Reports Server (NTRS)

    Wolff, D. M.

    1984-01-01

    The Infrared Astronomical Satellite (IRAS) is in a sun synchronous, 'near' polar orbit at an altitude of 900 km. The primary objective of IRAS is related to the conduction of an all-sky survey in the wavelength range from 8 microns to 120 microns. The present investigation is concerned with three components of the radiation environment encountered by IRAS, taking into account the high energy protons in the South Atlantic Anomaly, high energy electrons in the horns of the Van Allen belts, and cosmic rays. The effect of radiation on the returned data stream is studied, and attention is given to the steps which were taken to minimize the impact of radiation on the completeness of the survey.

  17. Effect of Growth on Fatty Acid Composition of Total Intramuscular Lipid and Phospholipids in Ira Rabbits

    PubMed Central

    Lu, Jingzhi; Li, Hongjun

    2015-01-01

    The changes in fatty acid composition of total intramuscular lipid and phospholipids were investigated in the longissimus dorsi, left-hind leg muscle, and abdominal muscle of male Ira rabbits. Changes were monitored at 35, 45, 60, 75, and 90 d. Analysis using gas chromatography identified 21 types of fatty acids. Results showed that the intramuscular lipid increased and the intramuscular phospholipids (total intramuscular lipid %) decreased in all muscles with increasing age (p<0.05). An abundant amount of unsaturated fatty acids, especially polyunsaturated fatty acids, was distributed in male Ira rabbits at different ages and muscles. Palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and arachidonic acid (C20:4) were the major fatty acids, which account to the dynamic changes of the n-6/n-3 value in Ira rabbit meat. PMID:26761795

  18. A study of deuterated water in the low-mass protostar IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Coutens, A.; Vastel, C.; Caux, E.; Ceccarelli, C.; Bottinelli, S.; Wiesenfeld, L.; Faure, A.; Scribano, Y.; Kahane, C.

    2012-03-01

    Context. Water is a primordial species in the emergence of life, and comets may have brought a large fraction to Earth to form the oceans. To understand the evolution of water from the first stages of star formation to the formation of planets and comets, the HDO/H2O ratio is a powerful diagnostic. Aims: Our aim is to determine precisely the abundance distribution of HDO towards the low-mass protostar IRAS 16293-2422 and learn more about the water formation mechanisms by determining the HDO/H2O abundance ratio. Methods: A spectral survey of the source IRAS 16293-2422 was carried out in the framework of the CHESS (Chemical Herschel Surveys of Star forming regions) Herschel key program with the HIFI (Heterodyne Instrument for the Far-Infrared) instrument, allowing detection of numerous HDO lines. Other transitions have been observed previously with ground-based telescopes. The spherical Monte Carlo radiative transfer code RATRAN was used to reproduce the observed line profiles of HDO by assuming an abundance jump. To determine the H2O abundance throughout the envelope, a similar study was made of the H218O observed lines, as the H2O main isotope lines are contaminated by the outflows. Results: It is the first time that so many HDO and H218O transitions have been detected towards the same source with high spectral resolution. We derive an inner HDO abundance (T ≥ 100 K) of about 1.7 × 10-7 and an outer HDO abundance (T < 100 K) of about 8 × 10-11. To reproduce the HDO absorption lines observed at 894 and 465 GHz, it is necessary to add an absorbing layer in front of the envelope. It may correspond to a water-rich layer created by the photodesorption of the ices at the edges of the molecular cloud. At a 3σ uncertainty, the HDO/H2O ratio is 1.4-5.8% in the hot corino, whereas it is 0.2-2.2% in the outer envelope. It is estimated at ~4.8% in the added absorbing layer. Conclusions: Although it is clearly higher than the cosmic D/H abundance, the HDO/H2O ratio remains

  19. OBSCURATION BY GAS AND DUST IN LUMINOUS QUASARS

    SciTech Connect

    Usman, S. M.; Murray, S. S.; Hickox, R. C.; Brodwin, M.

    2014-06-10

    We explore the connection between absorption by neutral gas and extinction by dust in mid-infrared (IR) selected luminous quasars. We use a sample of 33 quasars at redshifts 0.7 < z ≲ 3 in the 9 deg{sup 2} Boötes multiwavelength survey field that are selected using Spitzer Space Telescope Infrared Array Camera colors and are well-detected as luminous X-ray sources (with >150 counts) in Chandra observations. We divide the quasars into dust-obscured and unobscured samples based on their optical to mid-IR color, and measure the neutral hydrogen column density N {sub H} through fitting of the X-ray spectra. We find that all subsets of quasars have consistent power law photon indices Γ ≈ 1.9 that are uncorrelated with N {sub H}. We classify the quasars as gas-absorbed or gas-unabsorbed if N {sub H} > 10{sup 22} cm{sup –2} or N {sub H} < 10{sup 22} cm{sup –2}, respectively. Of 24 dust-unobscured quasars in the sample, only one shows clear evidence for significant intrinsic N {sub H}, while 22 have column densities consistent with N {sub H} < 10{sup 22} cm{sup –2}. In contrast, of the nine dust-obscured quasars, six show evidence for intrinsic gas absorption, and three are consistent with N {sub H} < 10{sup 22} cm{sup –2}. We conclude that dust extinction in IR-selected quasars is strongly correlated with significant gas absorption as determined through X-ray spectral fitting. These results suggest that obscuring gas and dust in quasars are generally co-spatial, and confirm the reliability of simple mid-IR and optical photometric techniques for separating quasars based on obscuration.

  20. A CANDIDATE FOR THE MOST LUMINOUS OB ASSOCIATION IN THE GALAXY

    SciTech Connect

    Rahman, Mubdi; Matzner, Christopher; Moon, Dae-Sik

    2011-02-20

    The Milky Way harbors giant H II regions, which may be powered by star complexes more luminous than any known Galactic OB association. Being across the disk of the Galaxy, however, these brightest associations are severely extinguished and confused. We present a search for one such association toward the most luminous H II region in the recent catalog by Murray and Rahman, which, at {approx}9.7 kpc, has a recombination rate of {approx}7 x 10{sup 51} s{sup -1}. Prior searches have identified only small-scale clustering around the rim of this shell-like region, but the primary association has not previously been identified. We apply a near-infrared color selection and find an overdensity of point sources toward its southern central part. The colors and magnitudes of these excess sources are consistent with O- and early B-type stars at extinctions 0.96 < A{sub K} < 1.2, and they are sufficiently numerous (406 {+-} 102 after subtraction of field sources) to ionize the surrounding H II region, making this a candidate for the most luminous OB association in the Galaxy. We reject an alternate theory, in which the apparent excess is caused by localized extinction, as inconsistent with source demographics.

  1. A Candidate for the Most Luminous OB Association in the Galaxy

    NASA Astrophysics Data System (ADS)

    Rahman, Mubdi; Matzner, Christopher; Moon, Dae-Sik

    2011-02-01

    The Milky Way harbors giant H II regions, which may be powered by star complexes more luminous than any known Galactic OB association. Being across the disk of the Galaxy, however, these brightest associations are severely extinguished and confused. We present a search for one such association toward the most luminous H II region in the recent catalog by Murray & Rahman, which, at ~9.7 kpc, has a recombination rate of ~7 × 1051 s-1. Prior searches have identified only small-scale clustering around the rim of this shell-like region, but the primary association has not previously been identified. We apply a near-infrared color selection and find an overdensity of point sources toward its southern central part. The colors and magnitudes of these excess sources are consistent with O- and early B-type stars at extinctions 0.96 < AK < 1.2, and they are sufficiently numerous (406 ± 102 after subtraction of field sources) to ionize the surrounding H II region, making this a candidate for the most luminous OB association in the Galaxy. We reject an alternate theory, in which the apparent excess is caused by localized extinction, as inconsistent with source demographics.

  2. IRAS observations of the ISM in the gamma CAS reflection nebula

    NASA Technical Reports Server (NTRS)

    Buss, Richard H., Jr.; Werner, Michael W.

    1990-01-01

    Mid-infrared emission from other galaxies originates both from interstellar grains heated by diffuse starlight and local excitation of grains by hot OB stars. Thus, a detailed examination of the Infrared Astronomy Satellite (IRAS) data from a B star interacting with the interstellar medium (ISM) could provide insight into infrared (IR) emission processes in external galaxies. Researchers have therefore used IRAS data to study the B0 IVe star gamma Cas and its surroundings, which they find to exhibit evidence of grain heating, destruction, and possible star formation.

  3. IRAS16293E revisited: a new understanding of a prestellar core in interaction with an outflow

    NASA Astrophysics Data System (ADS)

    Pagani, L.; Lefèvre, C.; Belloche, A.; Menten, K.; Parise, B.; Güsten, R.

    2016-05-01

    The study of prestellar cores starts with establishing their density and temperature structures. To explore the densest part, deu-terated species, N-bearing molecules, or dust are usually considered. Among prestellar cores, IRAS16293E is a rare case of a core being perturbed by the outflow of a nearby protostar (IRAS16293-2422 A/B). A part of the outflow hits the core and heats it, introducing a temperature gradient that makes the analysis difficult. It is only after having gathered observations from Spitzer, Herschel, SCUBA, MAMBO, and of various molecular lines from CSO, APEX, JCMT and IRAM that a clearer picture of this core has finally arisen.

  4. The Swift BAT Survey Detects Two Optical Broad Line, X-Ray Heavily Obscured Active Galaxies: NVSS 193013+341047 and IRAS 05218-1212

    NASA Astrophysics Data System (ADS)

    Hogg, J. Drew; Winter, Lisa M.; Mushotzky, Richard F.; Reynolds, Christopher S.; Trippe, Margaret

    2012-06-01

    The Swift Burst Alert Telescope (BAT) is discovering interesting new objects while monitoring the sky in the 14-195 keV band. Here we present the X-ray properties and spectral energy distributions (SEDs) for two unusual active galactic nucleus sources. Both NVSS 193013+341047 and IRAS 05218-1212 are absorbed, Compton-thin, but heavily obscured (N H ~ 1023 cm-2), X-ray sources at redshifts <0.1. The SEDs reveal these galaxies to be very red, with high extinction in the optical and UV. A similar SED is seen for the extremely red objects (EROs) detected in the higher redshift universe. This suggests that these unusual BAT-detected sources are a low-redshift (z Lt 1) analog to EROs, which recent evidence suggests are a class of the elusive type II quasars. Studying the multi-wavelength properties of these sources may reveal the properties of their high-redshift counterparts.

  5. Warm water deuterium fractionation in IRAS 16293-2422. The high-resolution ALMA and SMA view

    NASA Astrophysics Data System (ADS)

    Persson, M. V.; Jørgensen, J. K.; van Dishoeck, E. F.

    2013-01-01

    Context. Measuring the water deuterium fractionation in the inner warm regions of low-mass protostars has so far been hampered by poor angular resolution obtainable with single-dish ground- and space-based telescopes. Observations of water isotopologues using (sub)millimeter wavelength interferometers have the potential to shed light on this matter. Aims: To measure the water deuterium fractionation in the warm gas of the deeply-embedded protostellar binary IRAS 16293-2422. Methods: Observations toward IRAS 16293-2422 of the 53,2 - 44,1 transition of H218O at 692.07914 GHz from Atacama Large Millimeter/submillimeter Array (ALMA) as well as the 31,3 - 22,0 of H218O at 203.40752 GHz and the 31,2 - 22,1 transition of HDO at 225.89672 GHz from the Submillimeter Array (SMA) are presented. Results: The 692 GHz H218O line is seen toward both components of the binary protostar. Toward one of the components, "source B", the line is seen in absorption toward the continuum, slightly red-shifted from the systemic velocity, whereas emission is seen off-source at the systemic velocity. Toward the other component, "source A", the two HDO and H218O lines are detected as well with the SMA. From the H218O transitions the excitation temperature is estimated at 124 ± 12 K. The calculated HDO/H2O ratio is (9.2 ± 2.6) × 10-4 - significantly lower than previous estimates in the warm gas close to the source. It is also lower by a factor of ~5 than the ratio deduced in the outer envelope. Conclusions: Our observations reveal the physical and chemical structure of water vapor close to the protostars on solar-system scales. The red-shifted absorption detected toward source B is indicative of infall. The excitation temperature is consistent with the picture of water ice evaporation close to the protostar. The low HDO/H2O ratio deduced here suggests that the differences between the inner regions of the protostars and the Earth's oceans and comets are smaller than previously thought

  6. The evolution of and starburst-agn connection in luminous and ultraluminous infrared galaxies and their link to globular cluster formation

    NASA Astrophysics Data System (ADS)

    Fiorenza, Stephanie Lynn

    The evolutionary connection between nuclear starbursts and active galactic nuclei (AGN) in luminous infrared galaxies (LIRGs; 1011 < LIR < 1012 L[special character omitted]) and ultraluminous infrared galaxies (ULIRGs; 1012 < LIR < 1013 L[special character omitted]), which result from galaxy interactions and mergers and produce the bulk of their radiation as infrared (IR) emission, is not well understood. To this effort, I first spectroscopically examine U/LIRGs (1011 < LIR < 1013 L[special character omitted]) within the IRAS 2 Jansky Redshift Survey with 0.05 < z < 0.16. Using new spectrophotometric data, I classify the primary source of IR radiation as being a nuclear starburst or a type of AGN by using the Baldwin-Phillips-Terlevich (BPT) diagrams. I show that for the U/LIRGs in my sample the properties that describe their nuclear starbursts and AGN (e.g. star formation rate (SFR), L[O III], optical D parameter, D4000, and EW(Hdelta)) are independent of one another, ensuring that no biases affect correlations between these properties and objects' locations on the BPT diagrams. I then derive evolutionary paths on the BPT diagram involving [N II]/Halpha that are based on how these properties vary between two U/LIRGs positioned at the end-points. The paths involve U/LIRGs that decrease in SFR and increase in AGN activity. Paths with U/LIRGs that evolve into high luminosity AGN likely do so due to recent, strong starbursts. Second, to study how the properties of the IR power sources in U/LIRGs vary, I use a combination of photometric data points that I carefully measure (using photometry from SDSS, 2MASS, WISE, and Spitzer) and that I retrieve from catalogues (IRAS, AKARI, and ISO) to perform UV to FIR SED-fitting with CIGALE (Code Investigating GALaxy Emission) for 34 U/LIRGs from the IRAS 2 Jy Redshift Survey with 0.01 < z < 0.16. I find evidence that the nuclear starburst forms first in U/LIRGs, and also find that U/LIRGs with relatively similar SFRs show

  7. 2MASS-IRAS Discovery of New Candidate Vega-type Systems

    NASA Astrophysics Data System (ADS)

    Fajardo-Acosta, S. B.; Beichman, C. A.; Cutri, R. M.

    2000-12-01

    We obtained J (1.25 μ m), H (1.65 μ m), and Ks (2.17 μ m) photometry from the 2-Micron All-Sky Survey (2MASS), and 12, 25, 60, and 100 μ m photometry from the IRAS Faint Source Catalog (FSC), of field stars with galactic latitude > 20o. We identified main-sequence (luminosity class IV, IV--V, or V) stars using 3 methods: from previously known classifications; from Hipparcos distances and spectral types or J-Ks colors; or estimated from J-Ks, H-Ks colors. We searched this sample of main-sequence stars for excess 12 μ m emission with respect to the J, H, and Ks photospheric emission. This work is an extension of our previous survey of 2834 field stars, wherein we discovered, out of 296 main-sequence stars, 8 new candidate Vega-type systems with 12 μ m excesses (Fajardo-Acosta et al. 2000, ApJ, 538, L155). That survey was based on ≈ 35 % of the sky, and our new survey covers ≈ 75 % of the sky. We modeled the 12 μ m excess emission of our new cadidate systems, likely to arise from dust at ``terrestrial material'' temperatures, ~ 200--500 K, located at ~ 1-10 AU from the stars. Colder dust, more distant from the stars, might also exist in Kuiper Belt-like regions. We comment on the likelihood of spatially resolving these systems with current ground-based imaging technology. A fuller understanding of this dust may require more sensitive observations at long wavelengths by SIRTF. We acknowledge the support of the SIRTF Science Center, California Institute of Technology, which is operated under contract with the National Aeronautics and Space Administration.

  8. Star formation towards the southern cometary H II region IRAS 17256-3631

    NASA Astrophysics Data System (ADS)

    Veena, V. S.; Vig, S.; Tej, A.; Varricatt, W. P.; Ghosh, S. K.; Chandrasekhar, T.; Ashok, N. M.

    2016-03-01

    IRAS 17256-3631 is a southern Galactic massive star-forming region located at a distance of 2 kpc. In this paper, we present a multiwavelength investigation of the embedded cluster, the H II region, as well as the parent cloud. Radio images at 325, 610 and 1372 MHz were obtained using Giant Metrewave Radio Telescope, India while the near-infrared imaging and spectroscopy were carried out using United Kingdom Infrared Telescope and Mt. Abu Infrared Telescope, India. The near-infrared K-band image reveals the presence of a partially embedded infrared cluster. The spectral features of the brightest star in the cluster, IRS-1, spectroscopically agree with a late O or early B star and could be the driving source of this region. Filamentary H2 emission detected towards the outer envelope indicates the presence of highly excited gas. The parent cloud is investigated at far-infrared to millimetre wavelengths and 18 dust clumps have been identified. The spectral energy distributions of these clumps have been fitted as modified blackbodies and the best-fitting peak temperatures are found to range from 14 to 33 K, while the column densities vary from 0.7 to 8.5 × 1022 cm-2. The radio maps show a cometary morphology for the distribution of ionized gas that is density bounded towards the north-west and ionization bounded towards the south-east. This morphology is better explained with the champagne flow model as compared to the bow-shock model. Using observations at near-, mid- and far-infrared, submillimetre and radio wavelengths, we examine the evolutionary stages of various clumps.

  9. Luminal pulse velocity in a superluminal medium

    NASA Astrophysics Data System (ADS)

    Amano, Heisuke; Tomita, Makoto

    2015-12-01

    To investigate the physical meaning of pulse peak in fast and slow light media, we investigated propagation of differently shaped pulses experimentally, controlling the sharpness of the pulse peak. Symmetric behavior with respect to fast and slow light was observed in traditional Gaussian pulses; that is, propagated pulses were advanced or delayed, respectively, whereas the pulse shape remained unchanged. This symmetry broke down when the pulse peak was sharpened; in the fast light medium, the sharp pulse peak propagated with luminal velocity, and the transmitted pulse deformed into a characteristic asymmetric profile. In contrast, in the slow light medium, a time-delayed smooth peak appeared with a bending point at t =0 . This symmetry breaking with respect to fast and slow light is a universal characteristic of pulse propagation in causal dispersive systems. The sharp pulse peak can be recognized as a bending nonanalytical point and may be capable of transferring information.

  10. Shell nebulae around luminous evolved stars

    NASA Technical Reports Server (NTRS)

    Dufour, Reginald J.

    1989-01-01

    Shell nebulae around luminous Population I Wolf-Rayet, Of, and P-Cygni stars are astrophysically interesting since they are indicators of pre-supernova mass loss and how such massive stars prepare their surrounding interstellar medium prior to explosion. Some twenty-odd such nebulae are known, for which detailed study of their morphological and spectroscopic characteristics have only begun in this decade. In this paper, some of these characteristics are reviewed in general, and new observations are reported. Emphasis has been placed on several 'prototype 'objects (NGC 7635, NGC 2359, NGC 6888, and the Eta Carinae condensations) to illustrate the varied massive-star mass-loss, the physics of their winds and shell ejecta, and related nucleosynthesis effects in the compositions of the winds and shells.

  11. The Milky Way's Most Luminous Star Clusters: Engines of Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Rahman, Mubdi; Matzner, C. D.; Moon, D.

    2012-01-01

    Massive young star clusters and OB associations (M > 104 Msun) dominate the energetic feedback from stars into the interstellar medium. They contain the most massive and luminous stars in the Galaxy, which shape their environments through winds, ionizing flux, radiation pressure, and eventually supernovae, destroying their natal molecular clouds and inflating superbubbles. Few such clusters have been identified in our Galaxy. We systematically investigate the most luminous H II regions, which we identify using the WMAP foreground maps. We find that the 13 most luminous sources produce one-third of the Galaxy's total ionizing luminosity, all with expected powering populations of M > 4×104 Msun. These populations are grouped in small numbers of clusters or associations for each WMAP source. The emission from these regions is dominated by the diffuse component at large radii ( 10-70 pc) indicating a high leaking fraction of ionizing photons. Using 8 micron maps from Spitzer GLIMPSE and published radio recombination line observations, we resolve the large (>1°) WMAP sources into 40 star forming complexes (SFCs) exhibiting shell morphology with evidence of expansion due to a central powering source. We develop a method, based on differential extinction of the galactic disk, to identify the SFC's powering cluster candidates with 2MASS. We identify 25 candidate clusters within the 40 SFCs having extinctions consistent with their distances. With near-infrared spectroscopy from the New Technology Telescope, we have confirmed the existence of the most massive of these associations, the Dragonfish Association, with M = 105 Msun. Of the 50 sampled stars, we identify 2 Luminous Blue Variable candidates, a Wolf-Rayet, and 15 O-type stars, consistent with the yield expected from the candidate contamination rate, verifying the candidate cluster identification method. This investigation produces the most complete picture of the upper-end of the Galaxy's cluster mass function to

  12. Production of ball-lightning-like luminous balls by electrical discharges in silicon.

    PubMed

    Paiva, Gerson Silva; Pavão, Antonio Carlos; Alpes de Vasconcelos, Elder; Mendes, Odim; da Silva, Eronides Felisberto

    2007-01-26

    We performed electric arc discharges in pure Si to generate luminous balls with lifetime in the order of seconds and several properties usually reported for natural ball lightning. This simple experiment does not rely on energy sources and excitation mechanisms that are improbable in the natural phenomenon and clearly demonstrates the role of vaporization and oxidation of Si, as proposed by the Abrahamson-Dinniss theory for ball-lightning formation. PMID:17358820

  13. Production of Ball-Lightning-Like Luminous Balls by Electrical Discharges in Silicon

    NASA Astrophysics Data System (ADS)

    Paiva, Gerson Silva; Pavão, Antonio Carlos; Alpes de Vasconcelos, Elder; Mendes, Odim, Jr.; Felisberto da Silva, Eronides, Jr.

    2007-01-01

    We performed electric arc discharges in pure Si to generate luminous balls with lifetime in the order of seconds and several properties usually reported for natural ball lightning. This simple experiment does not rely on energy sources and excitation mechanisms that are improbable in the natural phenomenon and clearly demonstrates the role of vaporization and oxidation of Si, as proposed by the Abrahamson-Dinniss theory for ball-lightning formation.

  14. Covariation of Color and Luminance Facilitate Object Individuation in Infancy

    ERIC Educational Resources Information Center

    Woods, Rebecca J.; Wilcox, Teresa

    2010-01-01

    The ability to individuate objects is one of our most fundamental cognitive capacities. Recent research has revealed that when objects vary in color or luminance alone, infants fail to individuate those objects until 11.5 months. However, color and luminance frequently covary in the natural environment, thus providing a more salient and reliable…

  15. Effects of luminance and spatial noise on interferometric contrast sensitivity

    NASA Astrophysics Data System (ADS)

    Coletta, Nancy J.; Sharma, Vineeta

    1995-10-01

    Optical properties of the eye contribute to the reduced visibility of spatial patterns at low luminance. To study the limits of spatial vision when optical factors are minimized, we measured contrast-sensitivity functions (CSF's) for 543.5-nm laser interference fringes imaged directly on the retina. Measurements were made in the fovea at four luminance levels, ranging from 0.3 to 300 photopic trolands (Td). At each luminance the fraction of coherent light in the stimulus pattern was varied to assess the masking effects of laser speckle, which is visible as spatial noise in fields of coherent light. Compared with published CSF's obtained under natural viewing conditions, interferometric CSF's were similar in height but broader, with the range of visibility being extended to higher spatial frequencies. The masking effects of speckle were greatest at the highest luminance and were negligible at the lowest luminance. For low coherent fractions, contrast sensitivity improved over the entire luminance range at a rate consistent with a square-root law; with purely coherent light, sensitivity tended to level off at approximately 30 Td because of speckle masking. The results indicate that the optical quality of the eye reduces the spatial bandwidth of vision even at luminances near the foveal threshold. The change in interference fringe visibility with luminance is consistent with noise-limited behavior, and the masking

  16. Source detection for the infrared astronomical satellite

    NASA Technical Reports Server (NTRS)

    Aumann, H. H.; Hibbard, T. N.; Moyd, K. I.

    1980-01-01

    A recursive algorithm is described which detects and characterizes point sources and extended sources in the data obtained from the Infrared Astronomical Satellite (IRAS) in the presence of non-stationary noise. The analysis of tests using simulated data indicates that the performance of the point source detector is very close to that expected from a matched filter with stationary gaussian noise. The false alarm rate of the extended source detector tends to be higher than expected at a given SNR.

  17. The First Hyper-Luminous Infrared Galaxy Discovered by WISE

    NASA Technical Reports Server (NTRS)

    Eisenhardt, Peter R.; Wu, Jingwen; Tsai, Chao-Wei; Assef, Roberto; Benford, Dominic; Blain, Andrew; Bridge, Carrie; Condon, J. J.; Cushing, Michael C.; Cutri, Roc; Evans, Neal J., III; Gelino, Chris; Griffith, Roger L.; Grillmair, Carl J.; Jarrett, Tom; Lonsdale, Carol J.; Masci, Frank J.; Mason, Brian S.; Petty, Sara; Sayers, Jack; Stanford, S. Adam; Stern, Daniel; Wright, Edward L.; Yan, Lin

    2012-01-01

    We report the discovery by the Wide-field Infrared Survey Explorer of the z = 2.452 source WISEJ181417.29+341224.9, the first hyperluminous source found in the WISE survey. WISE 1814+3412 is also the prototype for an all-sky sample of approximately 1000 extremely luminous "W1W2-dropouts" (sources faint or undetected by WISE at 3.4 and 4.6 micrometers and well detected at 12 or 22 micrometers). The WISE data and a 350 micrometers detection give a minimum bolometric luminosity of 3.7 x 10(exp 13) solar luminosity, with approximately 10(exp 14) solar luminosity plausible. Followup images reveal four nearby sources: a QSO and two Lyman Break Galaxies (LBGs) at z = 2.45, and an M dwarf star. The brighter LBG dominates the bolometric emission. Gravitational lensing is unlikely given the source locations and their different spectra and colors. The dominant LBG spectrum indicates a star formation rate approximately 300 solar mass yr(exp -1), accounting for less than or equal to 10 percent of the bolometric luminosity. Strong 22 micrometer emission relative to 350 micrometer implies that warm dust contributes significantly to the luminosity, while cooler dust normally associated with starbursts is constrained by an upper limit at 1.1 mm. Radio emission is approximately 10? above the far-infrared/radio correlation, indicating an active galactic nucleus is present. An obscured AGN combined with starburst and evolved stellar components can account for the observations. If the black hole mass follows the local MBH-bulge mass relation, the implied Eddington ratio is approximately greater than 4. WISE 1814+3412 may be a heavily obscured object where the peak AGN activity occurred prior to the peak era of star formation.

  18. (-)-Reboxetine inhibits muscle nicotinic acetylcholine receptors by interacting with luminal and non-luminal sites.

    PubMed

    Arias, Hugo R; Ortells, Marcelo O; Feuerbach, Dominik

    2013-11-01

    The interaction of (-)-reboxetine, a non-tricyclic norepinephrine selective reuptake inhibitor, with muscle-type nicotinic acetylcholine receptors (AChRs) in different conformational states was studied by functional and structural approaches. The results established that (-)-reboxetine: (a) inhibits (±)-epibatidine-induced Ca(2+) influx in human (h) muscle embryonic (hα1β1γδ) and adult (hα1β1εδ) AChRs in a non-competitive manner and with potencies IC50=3.86±0.49 and 1.92±0.48 μM, respectively, (b) binds to the [(3)H]TCP site with ~13-fold higher affinity when the Torpedo AChR is in the desensitized state compared to the resting state, (c) enhances [(3)H]cytisine binding to the resting but activatableTorpedo AChR but not to the desensitized AChR, suggesting desensitizing properties, (d) overlaps the PCP luminal site located between rings 6' and 13' in the Torpedo but not human muscle AChRs. In silico mutation results indicate that ring 9' is the minimum structural component for (-)-reboxetine binding, and (e) interacts to non-luminal sites located within the transmembrane segments from the Torpedo AChR γ subunit, and at the α1/ε transmembrane interface from the adult muscle AChR. In conclusion, (-)-reboxetine non-competitively inhibits muscle AChRs by binding to the TCP luminal site and by inducing receptor desensitization (maybe by interacting with non-luminal sites), a mechanism that is shared by tricyclic antidepressants. PMID:23917086

  19. Enhancement of Luminous Efficacy by Random Patterning of Phosphor Matrix

    NASA Astrophysics Data System (ADS)

    Fellows, Natalie; Masul, Hisashi; Diana, Frederic; Denbaars, Steven P.; Nakamura, Shuji

    We have demonstrated the ability to increase the luminous flux and luminous efficacy of white light-emitting diodes (LEDs) by randomly patterning the surface of the yellow phosphor matrix. The phosphor was moved away from the LED die by placing it on top of a silicone optic and then roughening the surface of the phosphor/resin mixture. It was found that the roughening increases the luminous flux and efficacy by 10% over the smooth, non-patterned phosphor mixture. The roughened sample’s operating voltage, luminous flux, luminous efficacy, CCT, color coordinates, and CRI were 3.2 V, 7.4 lm, 115.6 lm/W, 4244 K, (0.388, 0.448), and 61 at 20 mA, CW, and room temperature operation. A brief presentation on phosphor scattering is introduced to help explain the effect of the roughening.

  20. Starburst or AGN Dominance in Submillimetre-Luminous Candidate AGN?

    NASA Astrophysics Data System (ADS)

    Coppin, Kristen; Pope, Alexandra; Menéndez-Delmestre, Karín; Alexander, David M.; Dunlop, James

    2010-06-01

    It is widely believed that ultraluminous infrared (IR) galaxies and active galactic nuclei (AGN) activity are triggered by galaxy interactions and merging, with the peak of activity occurring at z~2, where submillimetre galaxies are thousands of times more numerous than local ULIRGs. In this evolutionary picture, submillimetre galaxies (SMGs) would host an AGN, which would eventually grow a black hole (BH) strong enough to blow off all of the gas and dust leaving an optically luminous QSO. To probe this evolutionary sequence we have focussed on the `missing link' sources, which demonstrate both strong starburst (SB) and AGN signatures, in order to determine if the SB is the main power source even in SMGs when we have evidence that an AGN is present from their IRAC colours. The best way to determine if a dominant AGN is present is to look for their signatures in the mid-infrared with the Spitzer IRS, since often even deep X-ray observations miss identifying the presence of AGN in heavily dust-obscured SMGs. We present the results of our audit of the energy balance between star-formation and AGN within this special sub-population of SMGs-where the BH has grown appreciably to begin heating the dust emission.

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Deemed IRAs in qualified employer plans. 1.408(q)-1 Section 1.408(q)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Pension, Profit-Sharing, Stock Bonus Plans, Etc. §...

  2. Just Footprints in the Sand? Questioning Sustainability of an IRA International Project

    ERIC Educational Resources Information Center

    Lewis-Spector, Jill; Richardson, Judy S.; Janusheva, Violeta

    2011-01-01

    Volunteers from the International Reading Association (IRA) participated in the teacher education component of Macedonia's Secondary Education Activity, an initiative to reform vocational/technical education (VET), funded from 2004 to 2008 by USAID. Volunteers offered professional development to VET teachers using a trainer-of-trainers model,…

  3. VizieR Online Data Catalog: IRAS 1Jy sample of ultraluminous galaxies. II. (Veilleux+, 2002)

    NASA Astrophysics Data System (ADS)

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

    2003-01-01

    An R and K' atlas of the IRAS 1 Jy sample of 118 ultraluminous infrared galaxies (ULIGs) was presented in a companion paper (our Paper I, Kim et al., 2002, Cat. ). The present paper discusses the results from the analysis of these images supplemented with new spectroscopic data obtained at Keck. (2 data files).

  4. Evolutionary Paths along the BPT Diagram for Luminous and Ultraluminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Fiorenza, Stephanie L.; Takeuchi, Tsutomu T.; Małek, Katarzyna E.; Liu, Charles T.

    2014-04-01

    The evolutionary connection between nuclear starbursts and active galactic nuclei (AGNs) in luminous infrared galaxies (LIRGs) and ultraluminous infrared galaxies (ULIRGs), which result from galaxy interactions and mergers and produce the bulk of their radiation as infrared (IR) emission, is not well understood. To this effort, we present and examine new spectrophotometric data for five U/LIRGs (1011 < L IR < 1013 L ⊙) within the IRAS 2 Jy Redshift Survey with 0.05 <~ z <~ 0.07. We show that our sample consists almost entirely of composite objects—thus hosting both a nuclear starburst and an AGN—using the BPT diagrams. We then show that for our sample of U/LIRGs the properties that describe their nuclear starbursts and AGNs (e.g., star formation rate, L[O III], optical D parameter, D4000, and EW(Hδ)) are independent of one another, ensuring that no biases affect correlations between these parameters and the object locations on the BPT diagrams. Finally, we derive evolutionary paths on the BPT diagram involving {[N\\,{\\scriptsize{II}}]/H\\alpha } that are based on how these parameters vary between two U/LIRGs positioned at the end-points of these paths. The U/LIRGs at the end-points of a given path represent the beginning and end states of a U/LIRG evolving along that path. These paths may be able to specifically explain how all local U/LIRGs evolve along the BPT diagram, and serve as a starting point for future quantitative analysis on the evolution of U/LIRGs.

  5. Evolutionary paths along the BPT diagram for luminous and ultraluminous infrared galaxies

    SciTech Connect

    Fiorenza, Stephanie L.; Takeuchi, Tsutomu T.; Małek, Katarzyna E.; Liu, Charles T.

    2014-04-01

    The evolutionary connection between nuclear starbursts and active galactic nuclei (AGNs) in luminous infrared galaxies (LIRGs) and ultraluminous infrared galaxies (ULIRGs), which result from galaxy interactions and mergers and produce the bulk of their radiation as infrared (IR) emission, is not well understood. To this effort, we present and examine new spectrophotometric data for five U/LIRGs (10{sup 11} < L {sub IR} < 10{sup 13} L {sub ☉}) within the IRAS 2 Jy Redshift Survey with 0.05 ≲ z ≲ 0.07. We show that our sample consists almost entirely of composite objects—thus hosting both a nuclear starburst and an AGN—using the BPT diagrams. We then show that for our sample of U/LIRGs the properties that describe their nuclear starbursts and AGNs (e.g., star formation rate, L[O III], optical D parameter, D4000, and EW(Hδ)) are independent of one another, ensuring that no biases affect correlations between these parameters and the object locations on the BPT diagrams. Finally, we derive evolutionary paths on the BPT diagram involving [N II]/Hα that are based on how these parameters vary between two U/LIRGs positioned at the end-points of these paths. The U/LIRGs at the end-points of a given path represent the beginning and end states of a U/LIRG evolving along that path. These paths may be able to specifically explain how all local U/LIRGs evolve along the BPT diagram, and serve as a starting point for future quantitative analysis on the evolution of U/LIRGs.

  6. ASAS-SN Discovery of Two Probable Luminous Supernovae in Mrk 0283a and 2MASX J14021617+3339415

    NASA Astrophysics Data System (ADS)

    Masi, G.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Danilet, A. B.; Simonian, G.; Basu, U.; Beacom, J. F.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Brimacombe, J.; Falco, E.; Wozniak, P. R.; Szczygiel, D.; Pojmanski, G.; Fernandez, J. M.; Kiyota, S.; Nicholls, B.; Nicolas, J.

    2015-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered two luminous new transient sources, most likely supernovae, in the galaxies Mrk 0283a and 2MASX J14021617+3339415.

  7. Exploratory X-ray monitoring of luminous radio-quiet quasars at high redshift: Initial results

    SciTech Connect

    Shemmer, Ohad; Stein, Matthew S.; Brandt, W. N.; Schneider, Donald P.; Paolillo, Maurizio; Kaspi, Shai; Vignali, Cristian; Lira, Paulina; Gibson, Robert R.

    2014-03-10

    We present initial results from an exploratory X-ray monitoring project of two groups of comparably luminous radio-quiet quasars (RQQs). The first consists of four sources at 4.10 ≤ z ≤ 4.35, monitored by Chandra, and the second is a comparison sample of three sources at 1.33 ≤ z ≤ 2.74, monitored by Swift. Together with archival X-ray data, the total rest-frame temporal baseline spans ∼2-4 yr and ∼5-13 yr for the first and second group, respectively. Six of these sources show significant X-ray variability over rest-frame timescales of ∼10{sup 2}-10{sup 3} days; three of these also show significant X-ray variability on rest-frame timescales of ∼1-10 days. The X-ray variability properties of our variable sources are similar to those exhibited by nearby and far less luminous active galactic nuclei (AGNs). While we do not directly detect a trend of increasing X-ray variability with redshift, we do confirm previous reports of luminous AGNs exhibiting X-ray variability above that expected from their luminosities, based on simplistic extrapolation from lower luminosity sources. This result may be attributed to luminous sources at the highest redshifts having relatively high accretion rates. Complementary UV-optical monitoring of our sources shows that variations in their optical-X-ray spectral energy distribution are dominated by the X-ray variations. We confirm previous reports of X-ray spectral variations in one of our sources, HS 1700+6416, but do not detect such variations in any of our other sources in spite of X-ray flux variations of up to a factor of ∼4. This project is designed to provide a basic assessment of the X-ray variability properties of RQQs at the highest accessible redshifts that will serve as a benchmark for more systematic monitoring of such sources with future X-ray missions.

  8. Photodynamic therapy (PDT) and waterfiltered infrared A (wIRA) in patients with recalcitrant common hand and foot warts

    PubMed Central

    Fuchs, Silke M.; Fluhr, Joachim W.; Bankova, Lora; Tittelbach, Jörg; Hoffmann, Gerd; Elsner, Peter

    2004-01-01

    Background: Common warts (verrucae vulgares) are human papilloma virus (HPV) infections with a high incidence and prevalence, most often affecting hands and feet, being able to impair quality of life. About 30 different therapeutic regimens described in literature reveal a lack of a single striking strategy. Recent publications showed positive results of photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) in the treatment of HPV-induced skin diseases, especially warts, using visible light (VIS) to stimulate an absorption band of endogenously formed protoporphyrin IX. Additional experiences adding waterfiltered infrared A (wIRA) during 5-ALA-PDT revealed positive effects. Aim of the study: First prospective randomised controlled blind study including PDT and wIRA in the treatment of recalcitrant common hand and foot warts. Comparison of "5-ALA cream (ALA) vs. placebo cream (PLC)" and "irradiation with visible light and wIRA (VIS+wIRA) vs. irradiation with visible light alone (VIS)". Methods: Pre-treatment with keratolysis (salicylic acid) and curettage. PDT treatment: topical application of 5-ALA (Medac) in "unguentum emulsificans aquosum" vs. placebo; irradiation: combination of VIS and a large amount of wIRA (Hydrosun® radiator type 501, 4 mm water cuvette, waterfiltered spectrum 590-1400 nm, contact-free, typically painless) vs. VIS alone. Post-treatment with retinoic acid ointment. One to three therapy cycles every 3 weeks. Main variable of interest: "Percent change of total wart area of each patient over the time" (18 weeks). Global judgement by patient and by physician and subjective rating of feeling/pain (visual analogue scales). 80 patients with therapy-resistant common hand and foot warts were assigned randomly into one of the four therapy groups with comparable numbers of warts at comparable sites in all groups. Results: The individual total wart area decreased during 18 weeks in group 1 (ALA+VIS+wIRA) and in group 2 (PLC+VIS+wIRA

  9. Effects of radiation characteristic and luminous efficiency for LED lampshade with cylindrical lens

    NASA Astrophysics Data System (ADS)

    Chen, Hsi-Chao; Lin, Jun-Yu; Yang, Chi-Hao; Lu, Yi-Xuan

    2010-08-01

    Light emitting diode (LED) is an environmental-friendly product and could be a main lighting source in future. The research was to design a suitable LED lampshade for the street lighting. The radiation characteristic was required to be a rectangular distribution at the divergence-angle ratio of 7:3 for the x and y directions. Hence a design of two cylindrical lenses on the lampshade was used for the lighting distribution. Then an optimal simulation of these curvatures was done for the luminous distribution and efficiency. Final we got a rectangular lighting of the divergence-angle ratio of 7:3 and the radiator characteristic of bat-wing. The tolerance analyses of LED source distances were done on the x, y and z directions. The z direction was more sensibility than x and y directions for luminous efficiency and its tolerance must be kept under +/-0.5mm for the illumination efficiency to be over 95%. Anyway, the similar extent could reach to 98.46% by Normalized Cross Correlation (NCC) between experimental and simulation and the error extent could reduce to 6.87% by Root Mean Square (RMS) error mode. The total luminance efficiency could reach to 92% without AR coating.

  10. Molecular jets driven by high-mass protostars: a detailed study of the IRAS 20126+4104 jet

    NASA Astrophysics Data System (ADS)

    Caratti o Garatti, A.; Froebrich, D.; Eislöffel, J.; Giannini, T.; Nisini, B.

    2008-07-01

    Context: Protostellar jets from intermediate- and high-mass protostars provide an excellent opportunity to understand the mechanisms responsible for intermediate- and high-mass star-formation. A crucial question is if they are scaled-up versions of their low-mass counterparts. Such high-mass jets are relatively rare and, usually, they are distant and highly embedded in their parental clouds. The IRAS 20126+4104 molecular jet, driven by a 10^4 L⊙ protostar, represents a suitable target to investigate. Aims: We present here an extensive analysis of this protostellar jet, deriving the kinematical, dynamical, and physical conditions of the H2 gas along the flow. Methods: The jet was investigated by means of near-IR H2 and [Fe II] narrow-band imaging, high-resolution spectroscopy of the 1-0 S(1) line (2.12 μm), NIR (0.9-2.5 μm) low-resolution spectroscopy, along with ISO-SWS and LWS spectra (from 2.4 to 200 μm). Results: The flow shows a complex morphology. In addition to the large-scale jet precession presented in previous studies, we detect a small-scale wiggling close to the source, which may indicate the presence of a multiple system. The peak radial velocities of the H2 knots range from -42 to -14 km s-1 in the blue lobe, and from -8 to 47 km s-1 in the red lobe. The low-resolution spectra are rich in H2 emission, and relatively faint [Fe II] (NIR), [O I] and [C II] (FIR) emission is observed in the region close to the source. A warm H2 gas component has an average excitation temperature that ranges between 2000 K and 2500 K. Additionally, the ISO-SWS spectrum reveals a cold component (520 K) that strongly contributes to the radiative cooling of the flow and plays a major role in the dynamics of the flow. The estimated L_H2 of the jet is 8.2 ± 0.7 L⊙, suggesting that IRAS 20126+4104 has a significantly increased accretion rate compared to low-mass YSOs. This is also supported by the derived mass flux rate from the H2 lines (dot{M}_out(H2)˜ 7.5× 10-4 M

  11. A Second Luminous Blue Variable in the Quintuplet Cluster

    NASA Astrophysics Data System (ADS)

    Geballe, T. R.; Najarro, F.; Figer, D. F.

    2000-02-01

    H- and K-band moderate-resolution and 4 μm high-resolution spectra have been obtained for FMM 362, a bright star in the Quintuplet Cluster near the Galactic center. The spectral features in these bands closely match those of the Pistol Star, a luminous blue variable and one of the most luminous stars known. The new spectra and previously obtained photometry imply a very high luminosity for FMM 362, L>=106 Lsolar, and a temperature of 10,000-13,000 K. Based on its luminosity, temperature, photometric variability, and similarities to the Pistol Star, we conclude that FMM 362 is a luminous blue variable.

  12. Marine transducing bacteriophage attacking a luminous bacterium.

    PubMed

    Keynan, A; Nealson, K; Sideropoulos, H; Hastings, J W

    1974-08-01

    The isolation and partial characterization of a marine bacteriophage attacking a strain of luminous bacteria is described, including some physical, biological, and genetic properties. It is a DNA phage of density of 1.52 with a long flexible tail and an apparently icosohedral head. With respect to stability in suspension, it has a rather specific requirement for the sodium ion in high concentration; it is further stabilized by the addition of calcium and magnesium ions. These same ions are likewise all required for both good plating efficiency and plaque uniformity. Although it goes through a typical lytic growth cycle (about 45 min), with a burst size of 100, and no stable lysogens have been isolated, it is nevertheless a transducing phage specifically for the tryptophan region, transducing several, but not all, independently isolated Trp(-) auxotrophs to protrophy. No other auxotrophs of a variety of amino acids were transduced by this phage to prototrophy. Phage infection does not change the normal expression of the luminescent system, and light remains at near normal levels until cell lysis occurs. PMID:16789143

  13. Galaxy Clustering Around Nearby Luminous Quasars

    NASA Technical Reports Server (NTRS)

    Fisher, Karl B.; Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.

    1996-01-01

    We examine the clustering of galaxies around a sample of 20 luminous low redshift (z approx. less than 0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope (HST). The HST resolution makes possible galaxy identification brighter than V = 24.5 and as close as 1 min or 2 min to the quasar. We find a significant enhancement of galaxies within a projected separation of approx. less than 100 1/h kpc of the quasars. If we model the QSO/galaxy correlation function as a power law with a slope given by the galaxy/galaxy correlation function, we find that the ratio of the QSO/galaxy to galaxy/galaxy correlation functions is 3.8 +/- 0.8. The galaxy counts within r less than 15 1/h kpc of the quasars are too high for the density profile to have an appreciable core radius (approx. greater than 100 1/h kpc). Our results reinforce the idea that low redshift quasars are located preferentially in groups of 10-20 galaxies rather than in rich clusters. We see no significant difference in the clustering amplitudes derived from radio-loud and radio-quiet subsamples.

  14. Variability of the soft X-ray excess in IRAS 13224-3809

    NASA Astrophysics Data System (ADS)

    Kammoun, E. S.; Papadakis, I. E.; Sabra, B. M.

    2015-10-01

    We study the soft excess variability of the narrow line Seyfert 1 galaxy IRAS 13224-3809. We considered all five archival XMM-Newton observations, and we applied the flux-flux plot (FFP) method. We found that the FFPs were highly affected by the choice of the light curves' time bin size, most probably because of the fast and large amplitude variations, and the intrinsic non-linear flux-flux relations in this source. Therefore, we recommend that the smallest bin-size should be used in such cases. Hence, We constructed FFPs in 11 energy bands below 1.7 keV, and we considered the 1.7-3 keV band, as being representative of the primary emission. The FFPs are reasonably well fitted by a "power-law plus a constant" model. We detected significant positive constants in three out of five observations. The best-fit slopes are flatter than unity at energies below ~0.9 keV, where the soft excess is strongest. This suggests the presence of intrinsic spectral variability. A power-law-like primary component, which is variable in flux and spectral slope (as Γ∝ N_PL0.1) and a soft-excess component, which varies with the primary continuum (as Fexcess∝ F_primary0.46), can broadly explain the FFPs. In fact, this can create positive "constants", even when a stable spectral component does not exist. Nevertheless, the possibility of a stable, soft-band constant component cannot be ruled out, but its contribution to the observed 0.2-1 keV band flux should be less than ~15%. The model constants in the FFPs were consistent with zero in one observation, and negative at energies below 1 keV in another. It is hard to explain these results in the context of any spectral variability scenario, but they may signify the presence of a variable, warm absorber in the source.

  15. THE EXCEPTIONALLY LUMINOUS TYPE Ia SUPERNOVA 2007if

    SciTech Connect

    Yuan, F.; Akerlof, C. W.; Miller, J. M.; McKay, T. A.; Quimby, R. M.; Kulkarni, S.; Wheeler, J. C.; Vinko, J.; Chatzopoulos, E.; Aharonian, F.

    2010-06-01

    SN 2007if was the third over-luminous Type Ia supernova (SN Ia) detected after 2003fg and 2006gz. We present the photometric and spectroscopic observations of the SN and its host by ROTSE-III, HET, and Keck. From the H{sub {alpha}} line identified in the host spectra, we determine a redshift of 0.0736. At this distance, the SN reached an absolute magnitude of -20.4, brighter than any other SNe Ia ever observed. If the source of luminosity is radioactive decay, a large amount of radioactive nickel ({approx}1.5 M {sub sun}) is required to power the peak luminosity, more than can be produced realistically in a Chandrasekhar mass progenitor. Low expansion velocity, similar to that of 2003fg, is also measured around the maximum light. The observations may suggest that SN 2007if was from a massive white dwarf progenitor, plausibly exploding with mass well beyond 1.4 M {sub sun}. Alternatively, we investigate circumstellar interaction that may contribute to the excess luminosity.

  16. A global mechanism creating low atmospheric luminous cold plasmas

    NASA Astrophysics Data System (ADS)

    Gitle Hauge, Bjørn; Petter Strand, Erling

    2014-05-01

    Red, white/yellow and blue balls of light have been observed in the low atmosphere over the Hessdalen valley , Norway, standing still and moving horizontally with random speed. Characteristics of these transient luminous phenomena in Hessdalen, and data from America, suggest that the process which creates these low atmospheric plasmas is a global mechanism, not only localized to the remote and desolated Hessdalen valley in Norway (62Deg.N - 11Deg.E). Transient luminous phenomena's has been observed in the low atmosphere over the Hessdalen valley for over 200 years. The first written documentation goes back to 1811 when the priest Jakob Tode Krogh wrote about it in his diary. Since 1982, inhabitants, tourists, journalists and scientists have done recurrent observations. E.P.Strand conducted the first scientific campaign in 1984, documenting over 50 observations in one month. 15 years later, Norwegian and Italian scientists installed the first permanent automated research base here. In 2010 French researchers joined this collaboration and installed two additional research bases. This transient luminous phenomenon, TLP, has been detected simultaneously on optical and radar devices, but electromagnetic radiation from this phenomenon has until now eluded detection. Smirnov (1994) and Zou(1994) was among the first scientist who used plasma physics trying to explain this phenomenon. Work done by Pavia & Taft (2010 and 2012) suggests that the TLP in Hessdalen probably is dusty or cold plasma, arranged as a cluster of Coulomb crystals. Optical spectrum data obtained by Strand (1984), Teodorani (2004) and Hauge (2007) showing a continuous optical spectrum support this hypothesis. Pictures of spiraling light rays obtained by Strand in 1984, and Hauge in 2004 and 2010 suggests that this plasma is moving in a strong magnetic field, and might be created by it. Radar reflections from the TLP in Hessdalen obtained by Strand in 1984 and Montebugnoli and Monari in 2007 points

  17. Single luminal epithelial progenitors can generate prostate organoids in culture

    PubMed Central

    Chua, Chee Wai; Shibata, Maho; Lei, Ming; Toivanen, Roxanne; Barlow, LaMont J.; Bergren, Sarah K.; Badani, Ketan K.; McKiernan, James M.; Benson, Mitchell C.; Hibshoosh, Hanina; Shen, Michael M.

    2014-01-01

    The intrinsic ability to display self-organizing morphogenetic properties in ex vivo culture may represent a general property of tissue stem cells. Here we show that single luminal stem/progenitor cells can generate prostate organoids in a three-dimensional culture system in the absence of stroma. Organoids generated from CARNs (castration-resistant Nkx3.1-expressing cells) or normal prostate epithelium exhibit tissue architecture containing luminal and basal cells, undergo long-term expansion in culture, and display functional androgen receptor signaling. Lineage-tracing demonstrates that luminal cells are favored for organoid formation, and generate basal cells in culture. Furthermore, tumor organoids can initiate from CARNs after oncogenic transformation, and from mouse models of prostate cancer, and can facilitate analyses of drug response. Finally, we provide evidence supporting the feasibility of organoid studies of human prostate tissue. Our studies underscore the progenitor properties of luminal cells, and identify in vitro approaches for studying prostate biology. PMID:25241035

  18. Cue Combination of Conflicting Color and Luminance Edges.

    PubMed

    Sharman, Rebecca J; McGraw, Paul V; Peirce, Jonathan W

    2015-12-01

    Abrupt changes in the color or luminance of a visual image potentially indicate object boundaries. Here, we consider how these cues to the visual "edge" location are combined when they conflict. We measured the extent to which localization of a compound edge can be predicted from a simple maximum likelihood estimation model using the reliability of chromatic (L-M) and luminance signals alone. Maximum likelihood estimation accurately predicted the pattern of results across a range of contrasts. Predictions consistently overestimated the relative influence of the luminance cue; although L-M is often considered a poor cue for localization, it was used more than expected. This need not indicate that the visual system is suboptimal but that its priors about which cue is more useful are not flat. This may be because, although strong changes in chromaticity typically represent object boundaries, changes in luminance can be caused by either a boundary or a shadow. PMID:27551364

  19. Cue Combination of Conflicting Color and Luminance Edges

    PubMed Central

    Sharman, Rebecca J; McGraw, Paul V

    2015-01-01

    Abrupt changes in the color or luminance of a visual image potentially indicate object boundaries. Here, we consider how these cues to the visual “edge” location are combined when they conflict. We measured the extent to which localization of a compound edge can be predicted from a simple maximum likelihood estimation model using the reliability of chromatic (L−M) and luminance signals alone. Maximum likelihood estimation accurately predicted the pattern of results across a range of contrasts. Predictions consistently overestimated the relative influence of the luminance cue; although L−M is often considered a poor cue for localization, it was used more than expected. This need not indicate that the visual system is suboptimal but that its priors about which cue is more useful are not flat. This may be because, although strong changes in chromaticity typically represent object boundaries, changes in luminance can be caused by either a boundary or a shadow. PMID:27551364

  20. VizieR Online Data Catalog: Luminous X-ray candidates within D25 of galaxies (Gong+, 2016)

    NASA Astrophysics Data System (ADS)

    Gong, H.; Liu, J.; Maccarone, T.

    2016-02-01

    Using Chandra archive data we conduct a thorough survey of luminous X-ray sources. We directly analyze about 9400 ACIS Observations and cross-correlate the X-ray sources with 77000 galaxies within 250Mpc. The final catalog includes 119 unique luminous X-ray source candidates with LX>3x1040erg/s from 93 galaxies or 41 HLX candidates with LX>1x1041erg/s from 35 galaxies. We derive a moderate contamination rate due to foreground or background sources. We also cross-correlate the catalog with FIRST, perform variability and periodicity tests, and analyze one HLX candidate in particular. Our catalog could be a starting point to perform follow-up observations. (2 data files).

  1. Spatially resolved chemistry in nearby galaxies. III. Dense molecular gas in the inner disk of the LIRG IRAS 04296+2923

    SciTech Connect

    Meier, David S.; Turner, Jean L.; Beck, Sara C. E-mail: turner@astro.ucla.edu

    2014-11-10

    We present a survey of 3 mm molecular lines in IRAS 04296+2923, one of the brightest known molecular-line emitting galaxies, and one of the closest luminous infrared galaxies (LIRGs). Data are from the Owens Valley and CARMA millimeter interferometers. Species detected at ≲ 4'' resolution include C{sup 18}O, HCN, HCO{sup +}, HNC, CN, CH{sub 3}OH, and, tentatively, HNCO. Along with existing CO, {sup 13}CO, and radio continuum data, these lines constrain the chemical properties of the inner disk. Dense molecular gas in the nucleus fuels a star formation rate ≳10 M {sub ☉} yr{sup –1} and is traced by lines of HCN, HCO{sup +}, HNC, and CN. A correlation between HCN and star formation rate is observed on sub-kiloparsec scales, consistent with global relations. Toward the nucleus, CN abundances are similar to those of HCN, indicating emission comes from a collection (∼40-50) of moderate visual extinction, photon-dominated-region clouds. The CO isotopic line ratios are unusual: CO(1-0)/{sup 13}CO(1-0) and CO(1-0)/C{sup 18}O(1-0) line ratios are large toward the starburst, as is commonly observed in LIRGs, but farther out in the disk these ratios are remarkably low (≲ 3). {sup 13}CO/C{sup 18}O abundance ratios are lower than in Galactic clouds, possibly because the C{sup 18}O is enriched by massive star ejecta from the starburst. {sup 13}CO is underabundant relative to CO. Extended emission from CH{sub 3}OH indicates that dynamical shocks pervade both the nucleus and the inner disk. The unusual CO isotopologue ratios, the CO/HCN intensity ratio versus L {sub IR}, the HCN/CN abundance ratio, and the gas consumption time versus inflow rate all indicate that the starburst in IRAS 04296+2923 is in an early stage of development.

  2. IrAE – an asparaginyl endopeptidase (legumain) in the gut of the hard tick Ixodes ricinus

    PubMed Central

    Sojka, Daniel; Hajdušek, Ondřej; Dvořák, Jan; Sajid, Mohammed; Franta, Zdeněk; Schneider, Eric L.; Craik, Charles S.; Vancová, Marie; Burešová, Veronika; Bogyo, Matthew; Sexton, Kelly B.; McKerrow, James H.; Caffrey, Conor R.; Kopáček, Petr

    2008-01-01

    Ticks are ectoparasitic blood-feeders and important vectors for pathogens including arboviruses, rickettsiae, spirochetes and protozoa. As obligate blood-feeders, one possible strategy to retard disease transmission is disruption of the parasite’s ability to digest host proteins. However, the constituent peptidases in the parasite gut and their potential interplay in the digestion of the blood meal are poorly understood. We have characterized a novel asparaginyl endopeptidase (legumain) from the hard tick Ixodes ricinus (termed IrAE), which is the first such characterization of a clan CD family C13 cysteine peptidase (protease) in arthropods. By RT-PCR of different tissues, IrAE mRNA was only expressed in the tick gut. Indirect immunofluorescence and electron microscopy localized IrAE in the digestive vesicles of gut cells and within the peritrophic matrix. IrAE was functionally expressed in Pichia pastoris and reacted with a specific peptidyl fluorogenic substrate, and acyloxymethyl ketone and aza-asparagine Michael acceptor inhibitors. IrAE activity was unstable at pH ≥ 6.0 and was shown to have a strict specificity for asparagine at P1 using a positional scanning synthetic combinatorial library. The enzyme hydrolyzed protein substrates with a pH optimum of 4.5, consistent with the pH of gut cell digestive vesicles. Thus, IrAE cleaved the major protein of the blood meal, hemoglobin, to a predominant peptide of 4 kDa. Also, IrAE trans-processed and activated the zymogen form of Schistosoma mansoni cathepsin B1 – an enzyme contributing to hemoglobin digestion in the gut of that bloodfluke. The possible functions of IrAE in the gut digestive processes of I. ricinus are compared with those suggested for other hematophagous parasites. PMID:17336985

  3. Luminal flow alteration in presence of the stent

    NASA Astrophysics Data System (ADS)

    Bernad, E. S.; Hudrea, C. I.; Bernad, S. I.; Totorean, A. F.; Bosioc, A. I.

    2015-12-01

    Luminally protruding struts alter blood flow, creating areas of recirculation, separation, and stagnation. The impact of flow alterations around struts vary as the strut geometrical parameters change. We quantified the influence of the luminal flow alterations due to the presence of the stent struts by performing two-dimensional numerical simulation. Idealized computer models can facilitate understanding of the in-stent restenosis that is impossible to achieve in vivo.

  4. Luminance controlled pupil size affects Landolt C task performance. Revision

    SciTech Connect

    Berman, S.M.; Fein, G.; Jewett, D.L.; Ashford, F.

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m{sup 2} and 73 cd/m{sup 2}. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  5. Luminance controlled pupil size affects Landolt C task performance

    SciTech Connect

    Berman, S.M. ); Fein, G. ); Jewett, D.L.; Ashford, F. )

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m[sup 2] and 73 cd/m[sup 2]. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  6. FUSE Observations of Luminous Cool Stars

    NASA Astrophysics Data System (ADS)

    Dupree, A. K.; Young, P. R.; Ake, T. B.

    2000-12-01

    Luminous cool stars can address the evolution of magnetic activity and the dynamics of stellar winds and mass loss. The region of yellow supergiants in the HR diagram contains stars of intermediate mass both with coronas and those possessing a hot outer atmosphere in the presence of a strong wind (the ``hybrid'' stars). These hybrid objects hold particular significance for evolution studies because they represent the physically important connection between solar-like stars (with coronas and fast winds of low-mass loss rate) and the cool supergiant stars (Alpha Ori-like) with cool outer atmospheres and massive winds. The Far Ultraviolet Spectroscopic Explorer (FUSE) measured the chromospheric and transition region emissions of the bright G2 Ib supergiant Beta Draconis (HD 159181) on 9 May 2000. Two exposures through the large aperture totaled 7695 s and were obtained in all channels covering the region λ λ 912-1180. Emission from chromospheric and transition region ions (C III, O VI, Si III, S IV, S VI) is detected along with a number of low ion stages. Profiles of strong lines are asymmetric suggesting the presence of a wind. A short exposure (3260 s) of Alpha Aquarii (HD 209750), a hybrid supergiant also of spectral type G2 Ib was obtained June 29, 2000. Dynamics of the atmospheres can be inferred from line profiles. The atmospheric temperature distribution, densities, and scale sizes can be evaluated from line fluxes to characterize the differences between a coronal star and a hybrid supergiant. FUSE is a NASA Origins mission operated by The Johns Hopkins University. Funding for this research is provided through NASA Contract NAS-532985.

  7. STAR FORMATION IN TWO LUMINOUS SPIRAL GALAXIES

    SciTech Connect

    Hunter, Deidre A.; Ashburn, Allison; Wright, Teresa; Elmegreen, Bruce G.; Rubin, Vera C.; Józsa, Gyula I. G.; Struve, Christian

    2013-10-01

    We examined star formation in two very luminous (M{sub V} = –22 to –23) Sc-type spiral galaxies, NGC 801 and UGC 2885, using ultra-deep Hα images. We combine these Hα images with UBV and Two-Micron All-Sky Survey JHK images and H I maps to explore the star formation characteristics of disk galaxies at high luminosity. Hα traces star formation in these galaxies to 4-6 disk scale lengths, but the lack of detection of Hα further out is likely due to the loss of Lyman continuum photons. Considering gravitational instabilities alone, we find that the gas and stars in the outer regions are marginally stable in an average sense, but considering dissipative gas and radial and azimuthal forcing, the outer regions are marginally unstable to forming spiral arms. Star formation is taking place in spiral arms, which are regions of locally higher gas densities. Furthermore, we have traced smooth exponential stellar disks over four magnitudes in V-band surface brightness and 4-6 disk scale lengths, in spite of a highly variable gravitational instability parameter. Thus, gravitational instability thresholds do not seem relevant to the stellar disk. One possibility for creating an exponential disk is that the molecular cloud densities and star formation rates have exponential profiles and this fact forces the stellar disk to build up such a profile. Another possibility is that the stellar disk is continuously adjusted to an exponential shape regardless of the star formation profile, for example, through global dynamical processes that scatter stars. However, such scattering processes are only known to operate in spiral systems, in which case they cannot explain the same dilemma of smooth exponential disks observed in dwarf irregular galaxies.

  8. Luminous red galaxies in hierarchical cosmologies

    NASA Astrophysics Data System (ADS)

    Almeida, C.; Baugh, C. M.; Wake, D. A.; Lacey, C. G.; Benson, A. J.; Bower, R. G.; Pimbblet, K.

    2008-06-01

    Luminous red galaxies (LRGs) are much rarer and more massive than L* galaxies. Coupled with their extreme colours, LRGs therefore provide a demanding testing ground for the physics of massive galaxy formation. We present the first self-consistent predictions for the abundance and properties of LRGs in hierarchical structure formation models. We test two published models which use quite different mechanisms to suppress the formation of massive galaxies: the Bower et al. model which invokes `active galactic nuclei (AGN) feedback' to prevent gas from cooling in massive haloes and the Baugh et al. model which relies upon a `superwind' to eject gas before it is turned into stars. Without adjusting any parameters, the Bower et al. model gives an excellent match to the observed luminosity function of LRGs in the Sloan Digital Sky Survey (with a median redshift of z = 0.24) and to their clustering; the Baugh et al. model is less successful in these respects. Both models fail to match the observed abundance of LRGs at z = 0.5 to better than a factor of ~2. In the models, LRGs are typically bulge-dominated systems with stellar masses of ~2 × 1011h-1Msolar and velocity dispersions of σ ~ 250kms-1. Around half of the stellar mass in the model LRGs is already formed by z ~ 2.2 and is assembled into one main progenitor by z ~ 1.5; on average, only 25 per cent of the mass of the main progenitor is added after z ~ 1. LRGs are predicted to be found in a wide range of halo masses, a conclusion which relies on properly taking into account the scatter in the formation histories of haloes. Remarkably, we find that the correlation function of LRGs is predicted to be a power law down to small pair separations, in excellent agreement with observational estimates. Neither the Bower et al. nor the Baugh et al. model is able to reproduce the observed radii of LRGs.

  9. Evolution of local luminous compact blue galaxies

    NASA Astrophysics Data System (ADS)

    Rabidoux, Katherine; Pisano, Daniel J.

    2015-01-01

    Luminous compact blue galaxies (LCBGs) are a type of very blue, very compact star-forming galaxy that was common at z~1 but is rare in the local universe. While it is clear from this discrepancy that LCBGs must be a rapidly-evolving class of galaxy, it is not clear what type(s) of galaxy they become. Fortunately, since they are bright and nearby, the rare examples of z~0 LCBGs are easily studied across a large range of wavelengths. We have conducted a study of z~0 analogs to the z~1 LCBGs to investigate their galaxy-wide internal properties in order to determine what is triggering their current episode of star formation, for how long the star formation can continue, and what the galaxies may become once their star formation rates decrease from current levels. We have taken resolved H I observations of nine LCBGs and unresolved radio continuum observations of 35 LCBGs and combined this data with archival broad-band data to probe their global properties. We conclude that LCBGs are rotationally-supported, star-forming disk galaxies that, while they may be forming small central bulges or bars, are highly unlikely to evolve into dwarf elliptical, dwarf spheroidal, or elliptical galaxies on their own due to their masses and rotation velocities. LCBGs will likely fade to be spiral galaxies with lower surface brightnesses once their current episodes of star formation conclude. In addition, we have modeled the SEDs of the LCBGs in our sample to determine whether LCBGs' star formation is ramping up or winding down, and for how much longer their current active phase of star formation will last. We have begun to put together a picture of the current evolutionary stage of this class of galaxies, and have better constrained their future evolutionary paths.

  10. The Luminous Convolution Model for Galaxy Rotation Curves

    NASA Astrophysics Data System (ADS)

    Rubin, Shanon; Mucci, Maria; Sophia Cisneros Collaboration; Kennard Chng Collaboration; Meagan Crowley Collaboration

    2016-03-01

    The LCM takes as input only the observed luminous matter profile from galaxies, and allows us to confirm these observed data by considering frame-dependent effects from the luminous mass profile of the Milky Way. The LCM is useful when looking at galaxies that have similar total enclosed mass, but varying distributions. For example, variations in luminous matter profiles from a diffuse galaxy correlate to the LCM's five different Milky Way models equally well, but LCM fits for a centrally condensed galaxy distinguish between Milky Way models. In this presentation, we show how the rotation curve data of such galaxies can be used to constrain the Milky Way luminous mass modeling, by the physical characteristics of each galaxy used to interpret the fitting. Current Investigations will be presented showing how the convolved parameters of Keplerian predictions with rotation curve observations can be extracted with respect to the crossing location of the relative curvature versus the assumption of the luminous mass profiles from photometry. Since there currently exists no direct constraint to photometric estimates of the luminous mass in these systems, the LCM gives the first constraint based on the orthogonal measurement of Doppler shifted spectra from characteristic emitters.

  11. Luminous-flux measurements by an absolute integrating sphere

    NASA Astrophysics Data System (ADS)

    Rastello, Maria Luisa; Miraldi, Elio; Pisoni, Paolo

    1996-08-01

    We present an original implementation of the absolute-sphere method recently proposed by Ohno. The luminous-flux unit, the lumen, is realized by means of an integrating sphere with an opening calibrated by a luminous-intensity standard placed outside. The adapted experimental setup permits one to measure luminous-flux values between 5 and 2500 lm with a significant improvement with respect to the simulated performances reported in the literature. Traditionally, the luminous-flux unit, the lumen, is realized by goniophotometric techniques in which the luminous-intensity distribution is measured and integrated over the whole solid angle. Thus sphere results are compared with those obtained with the Istituto Elettrotecnico Nazionale goniophotometer. In particular, a set of standards, characterized by luminous-flux values of approximately 2000 lm, has been calibrated with both techniques. We highlight some of the problems encountered. Experimental results show that the agreement between the two methods is within the estimated uncertainty and suggest promising areas for future research.

  12. Dynamics of backlight luminance for using smartphone in dark environment

    NASA Astrophysics Data System (ADS)

    Na, Nooree; Jang, Jiho; Suk, Hyeon-Jeong

    2014-02-01

    This study developed dynamic backlight luminance, which gradually changes as time passes for comfortable use of a smartphone display in a dark environment. The study was carried out in two stages. In the first stage, a user test was conducted to identify the optimal luminance by assessing the facial squint level, subjective glare evaluation, eye blink frequency and users' subjective preferences. Based on the results of the user test, the dynamics of backlight luminance was designed. It has two levels of luminance: the optimal level for initial viewing to avoid sudden glare or fatigue to users' eyes, and the optimal level for constant viewing, which is comfortable, but also bright enough for constant reading of the displayed material. The luminance for initial viewing starts from 10 cd/m2, and it gradually increases to 40 cd/m2 for users' visual comfort at constant viewing for 20 seconds; In the second stage, a validation test on dynamics of backlight luminance was conducted to verify the effectiveness of the developed dynamics. It involving users' subjective preferences, eye blink frequency, and brainwave analysis using the electroencephalogram (EEG) to confirm that the proposed dynamic backlighting enhances users' visual comfort and visual cognition, particularly for using smartphones in a dark environment.

  13. Effects of Narrow-band IR-A and of Water-Filtered Infrared A on Fibroblasts.

    PubMed

    Knels, Lilla; Valtink, Monika; Piazena, Helmut; de la Vega Marin, Jamlec; Gommel, Kerstin; Lupp, Amelie; Roehlecke, Cora; Mehner, Mirko; Funk, Richard H W

    2016-05-01

    Exposures of the skin with electromagnetic radiation of wavelengths between 670 nm and 1400 nm are often used as a general treatment to improve wound healing and reduce pain, for example, in chronic diabetic skin lesions. We investigated the effects of water-filtered infrared A (wIRA) and of narrow-band IR-A provided by a light-emitting diode LED (LED-IR-A) irradiation in vitro on 3T3 fibroblast cultures under defined conditions with and without glyoxal administration. Glyoxal triggers the formation of advanced glycation end products, thereby mimicking a diabetic metabolic state. Cell viability and apoptotic changes were determined by flow cytometry after vital staining with Annexin V, YO-PRO-1 and propidium iodide (PI), and by SubG1 assay. Mitochondrial function and oxidative stress were examined by vital staining for radical production, mitochondrial membrane potential (MMP) and the ratio of reduced-to-oxidized glutathione (GSH/GSSG). The metabolic state was monitored by a resazurin conversion assay. The numbers of apoptotic cells were reduced in cultures irradiated with wIRA or LED-IR-A. More mitochondria showed a well-polarized MMP after wIRA irradiation in glyoxal damaged cells. LED-IR-A treatment specifically restored the GSH/GSSG ratio. The immediate positive effects of wIRA and LED-IR-A observed in living cells, particularly on mitochondria, reflect the therapeutic benefits of wIRA and LED-IR-A. PMID:26876482

  14. Starburst or AGN dominance in submm-luminous candidate AGN

    NASA Astrophysics Data System (ADS)

    Coppin, Kristen; Alexander, Dave; Aretxaga, Itziar; Blain, Andrew; Chapman, Scott; Clements, Dave; Dunlop, James; Dunne, Loretta; Dye, Simon; Farrah, Duncan; Hughes, David; Ivison, Rob; Kim, Sungeun; Menendez-Delmestre, Karin; Oliver, Sebastian; Page, Mat; Pope, Alexandra; Rowan-Robinson, Michael; Scott, Douglas; Smail, Ian; Swinbank, Mark; Vaccari, Mattia; van Kampen, Eelco

    2008-03-01

    It is widely believed that starbursts/ULIRGs and AGN activity are triggered by galaxy interactions and merging; and sub-mm selected galaxies (SMGs) seem to be simply high redshift ULIRGs, observed near the peak of activity. In this evolutionary picture every SMG would host an AGN, which would eventually grow a black hole strong enough to blow off all of the gas and dust leaving an optically luminous QSO. In order to probe this evolutionary sequence, a crucial sub-sample to focus on would be the 'missing link' sources, which demonstrate both strong starburst and AGN signatures and to determine if the starburst is the main power source even in SMGs when we have evidence that an AGN is present. The best way to determine if a dominant AGN is present is to look in the mid-IR for their signatures, since often even deep X-ray observations miss identifying the presence of AGN in heavily dust-obscured SMGs. We have selected a sample of SMGs which are good candidates for harboring powerful AGN on the basis of their IRAC colours (S8um/S4.5um>2). Once we confirm these SMGs are AGN-dominated, we can then perform an audit of the energy balance between star-formation and AGN within this special sub-population of SMGs where the BH has grown appreciably to begin heating the dust emission. The proposed observations with IRS will probe the physics of how SMGs evolve from a cold-dust starburst-dominated ULIRG to an AGN/QSO by measuring the level of the mid-IR continuum, PAH luminosity, and Si absorption in these intermediate `transitory' AGN/SMGs.

  15. Imaging Polarimetry of Scattered Light from the Buried QSO in IRAS F15307+3252

    NASA Astrophysics Data System (ADS)

    Gerber, Jeffrey; Hines, D. C.

    2013-01-01

    We present new imaging polarimetry observations of the Hyperluminous Infrared Galaxy and Type 2 QSO IRAS F15307+3252 (z = 0.9257). The observations were obtained with the High-Resolution Camera (HRC) of the Advance Camera for Surveys (ACS) aboard the Hubble Space Telescope (HST). The images show strongly polarized (p ≥ 20%) light extending ~8 kpc southwest from the center of the galaxy. The overall shape suggests that the extended emission has a single-sided, conical structure of apparent half-opening angle ~16 degrees and apex centered at the galaxy nucleus. The polarization position angle (at each resolution element) is perpendicular to the axis of the extended emission, implying that the structure is illuminated by a central source in the galaxy nucleus that is not seen directly. F15307+3252 is known to harbor a buried QSO that was revealed in a polarized spectrum by Hines et al. (1995); the degree of polarization and position angle of this polarized spectrum match those of the extended structure seen in our new HST/ACS data. We thus conclude that this extended emission is light from the buried QSO that is scattered (thus polarized) into our line of sight, and importantly, this object would be classified optically as a Type 1 QSO if viewed from the vantage point of the scattering material. The conical structure of the scattered light suggests that the material blocking our direct line of sight to the QSO has a spatial distribution similar to the dusty torus in lower redshift Active Galactic Nuclei (AGNs). Assuming that the scattered-light-cone half-opening angle is the same as the dusty torus half-opening angle, we derive a dust-covering fraction of ≥ 95%. This, and comparison between the observed spectral energy distribution of F15307+3252 and that of a composite Type 1 QSO, suggests that the majority of the luminosity in F15307+3252 is powered by the central QSO. Deep HST/ACS images in total light also show clearly that F15307+3252 sits at the center of a

  16. Spectral and luminous efficacy change of high-power LEDs under different dimming methods

    NASA Astrophysics Data System (ADS)

    Gu, Yimin; Narendran, Nadarajah; Dong, Tianming; Wu, Huiying

    2006-08-01

    Dimming is an important and necessary feature for light sources used in general lighting applications. An experimental study was conducted to quantify the spectral and luminous efficacy change of high-power colored and pc-white LEDs under continuous current reduction (CCR) and pulse-width modulation (PWM) dimming schemes. For InGaN-based blue, green, and pc-white LEDs, the peak wavelength shifts were in opposite directions for the two dimming schemes. The peak wavelength showed a blue shift with increased current, most likely due to band filling and QCSE dominated effects. InGaN LEDs exhibited red shifts with increased duty cycle, which is dominated by junction heat. AlInGaP red LEDs show mainly thermal-induced red shift with increased current or duty cycle. In addition, the luminous efficacy was always higher for the CCR dimming scheme at dimmed levels, irrespective of the LED type. Keywords: Light-emitting diodes (LEDs), white LEDs, mixed-color white LEDs, pulse-width modulation (PWM), continuous current reduction (CCR), peak wavelength shift, luminous efficacy

  17. Radiation properties of two types of luminous textile devices containing plastic optical fibers

    NASA Astrophysics Data System (ADS)

    Selm, Bärbel; Rothmaier, Markus

    2007-05-01

    Luminous textiles have the potential to satisfy a need for thin and flexible light diffusers for treatment of intraoral cancerous tissue. Plastic optical fibers (POF) with diameters of 250 microns and smaller are used to make the textiles luminous. Usually light is supplied to the optical fiber at both ends. On the textile surface light emission occurs in a woven structure via damaged straight POFs, whereas the embroidered structure radiates the light out of macroscopically bent POFs. We compared the optical properties of these two types of textile diffusers using red light laser for the embroidery and light emitting diode (LED) for the woven structure as light sources, and found efficiencies for the luminous areas of the two samples of 19 % (woven) and 32 % (embroidery), respectively. It was shown that the efficiency can be greatly improved using an aluminium backing. Additional scattering layers lower the fluence rate by around 30 %. To analyse the homogeneity we took a photo of the illuminated surface using a 3CCD camera and found, for both textiles, a slightly skewed distribution of the dark and bright pixels. The interquartile range of brightness distribution of the embroidery is more than double as the woven structure.

  18. DISCOVERY OF 6.035 GHz HYDROXYL MASER FLARES IN IRAS 18566+0408

    SciTech Connect

    Al-Marzouk, A. A.; Araya, E. D.; Hofner, P.; Kurtz, S.; Linz, H.; Olmi, L.

    2012-05-10

    We report the discovery of 6.035 GHz hydroxyl (OH) maser flares toward the massive star-forming region IRAS 18566+0408 (G37.55+0.20), which is the only region known to show periodic formaldehyde (4.8 GHz H{sub 2}CO) and methanol (6.7 GHz CH{sub 3}OH) maser flares. The observations were conducted between 2008 October and 2010 January with the 305 m Arecibo Telescope in Puerto Rico. We detected two flare events, one in 2009 March and one in 2009 September to November. The OH maser flares are not simultaneous with the H{sub 2}CO flares, but may be correlated with CH{sub 3}OH flares from a component at corresponding velocities. A possible correlated variability of OH and CH{sub 3}OH masers in IRAS 18566+0408 is consistent with a common excitation mechanism (IR pumping) as predicted by theory.

  19. OH prompt emission in Comet IRAS-Araki-Alcock (1983 VII)

    NASA Technical Reports Server (NTRS)

    Budzien, S. A.; Feldman, P. D.

    1991-01-01

    Following Bertaux's (1986) suggestion that photodissociative OH fluorescence can furnish a direct measure of water-density distribution within about 100 km of the cometary nucleus, if sufficiently high spatial resolution is available, attention is presently given to IUE-obtained UV spectra of two comets which differ only as to effective spatial resolution, in order to search for OH prompt emission. IRAS-Araki-Alcock (1983 VII) and Tuttle (1980 XIII) spectra are compared at comparable heliocentric, but differing geocentric, distances; evidence is thereby obtained for OH prompt emission in Comet IRAS-Araki-Alcock, whose implied water-production rate reflects an instantaneous value which may be compared with that derived from OH solar resonance fluorescence.

  20. Herschel/HIFI-HRS observation of CH absorption in IRAS16293-2422

    NASA Astrophysics Data System (ADS)

    Bottinelli, S.; Caux, C.; Wakelam, V.; Ceccarelli, C.; Kahane, C.

    2011-05-01

    We present high spectral resolution observations of CH absorption towards the low-mass protostar IRAS16293-2422. The data were obtained with the High Resolution Spectrometer (HRS) module of the Heterodyne Instrument for the Far-Infrared (HIFI) on-board Herschel, as part of the CHESS (Chemical HErschel Surveys of Star-forming regions) guaranteed time key program. CH is well known for having column densities correlated with those of H_2 and for its role as a product in the ion-molecule gas-phase chemistry. We derive CH column densities in the envelope of IRAS16293-2422, and investigate the implications when comparing with column densities of H_2 and of other carbon species such as CN or CCH. We also discuss the non-detections of CD and CH^+.