Search Publications
The Spitzer Ice Legacy: Ice Evolution from Cores to Protostars
Öberg, Karin I.; van Dishoeck, Ewine F.; Pontoppidan, Klaus M. +5 more
Ices regulate much of the chemistry during star formation and account for up to 80% of the available oxygen and carbon. In this paper, we use the Spitzer c2d Legacy ice survey, complimented with data sets on ices in cloud cores and high-mass protostars, to determine standard ice abundances and to present a coherent picture of the evolution of ices…
Observations of Arp 220 Using Herschel-SPIRE: An Unprecedented View of the Molecular Gas in an Extreme Star Formation Environment
Clements, D. L.; Wilson, Christine D.; Baes, Maarten +20 more
We present Herschel Spectral and Photometric Imaging Receiver Fourier Transform Spectrometer (Herschel SPIRE-FTS) observations of Arp 220, a nearby ultra-luminous infrared galaxy. The FTS provides continuous spectral coverage from 190 to 670 µm, a wavelength region that is either very difficult to observe or completely inaccessible from the …
Line Derived Infrared Extinction toward the Galactic Center
Lutz, D.; Genzel, R.; Gillessen, S. +7 more
We derive the extinction curve toward the Galactic center (GC) from 1 to 19 µm. We use hydrogen emission lines of the minispiral observed by ISO-SWS and SINFONI. The extinction-free flux reference is the 2 cm continuum emission observed by the Very Large Array. Toward the inner 14'' × 20'', we find an extinction of A 2.166 µm
Far-infrared Line Deficits in Galaxies with Extreme L_{FIR}/M_{H_{2}} Ratios
Lutz, D.; Genzel, R.; Poglitsch, A. +13 more
We report initial results from the far-infrared fine structure line observations of a sample of 44 local starbursts, Seyfert galaxies, and infrared luminous galaxies obtained with the PACS spectrometer on board Herschel. We show that the ratio between the far-infrared luminosity and the molecular gas mass, {L_{FIR}/{M_{H_{2}}, is a much better pro…
Ice and Dust in the Quiescent Medium of Isolated Dense Cores
van Dishoeck, E. F.; Blake, G. A.; Decin, L. +6 more
The relation between ices in the envelopes and disks surrounding young stellar objects (YSOs) and those in the quiescent interstellar medium (ISM) is investigated. For a sample of 31 stars behind isolated dense cores, ground-based and Spitzer spectra and photometry in the 1-25 µm wavelength range are combined. The baseline for the broad and …
Are C60 Molecules Detectable in Circumstellar Shells of R Coronae Borealis Stars?
Lambert, D. L.; García-Hernández, D. A.; Kameswara Rao, N.
The hydrogen-poor, helium-rich, and carbon-rich character of the gas around R Coronae Borealis (RCB) stars has been suggested to be a site for formation of C60 molecules. This suggestion is not supported by observations reported here showing that infrared transitions of C60 are not seen in a large sample of RCB stars observed…
Detection of the Cosmic Far-infrared Background in AKARI Deep Field South
Clements, D. L.; White, G. J.; Burgarella, D. +14 more
We report new limits on the absolute brightness and spatial fluctuations of the cosmic infrared background (CIB) via the AKARI satellite. We carried out observations at 65, 90, 140, and 160 µm as a cosmological survey in AKARI Deep Field South, which is one of the lowest cirrus regions with a contiguous area of the sky. After removing bright…
The Mass-loss Return from Evolved Stars to the Large Magellanic Cloud. IV. Construction and Validation of a Grid of Models for Oxygen-rich AGB Stars, Red Supergiants, and Extreme AGB Stars
Meixner, M.; Sargent, Benjamin A.; Srinivasan, S.
To measure the mass loss from dusty oxygen-rich (O-rich) evolved stars in the Large Magellanic Cloud (LMC), we have constructed a grid of models of spherically symmetric dust shells around stars with constant mass-loss rates using 2Dust. These models will constitute the O-rich model part of the "Grid of Red supergiant and Asymptotic giant branch s…
A Submillimeter Mapping Survey of Herbig AeBe Stars
Sandell, Göran; Weintraub, David A.; Hamidouche, Murad
We have acquired submillimeter observations of 33 fields containing 37 Herbig Ae/Be (HAEBE) stars or potential HAEBE stars, including SCUBA maps of all but two of these stars. Nine target stars show extended dust emission. The other 18 are unresolved, suggesting that the dust envelopes or disks around these stars are less than a few arcseconds in …
A 205 µm [N II] Map of the Carina Nebula
Stark, A. A.; Stacey, G. J.; Kamenetzky, J. +5 more
We present the results of a ~250 arcmin2 mapping of the 205 µm [N II] fine-structure emission over the northern Carina Nebula, including the Car I and Car II H II regions. Spectra were obtained using the South Pole Imaging Fabry-Perot Interferometer (SPIFI) at the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) a…