Search Publications
The Spitzer c2d Legacy Results: Star-Formation Rates and Efficiencies; Evolution and Lifetimes
Myers, Philip C.; Dunham, Michael M.; Alcalá, Juan M. +15 more
The c2d Spitzer Legacy project obtained images and photometry with both IRAC and MIPS instruments for five large, nearby molecular clouds. Three of the clouds were also mapped in dust continuum emission at 1.1 mm, and optical spectroscopy has been obtained for some clouds. This paper combines information drawn from studies of individual clouds int…
Spitzer Quasar and Ulirg Evolution Study (QUEST). IV. Comparison of 1 Jy Ultraluminous Infrared Galaxies with Palomar-Green Quasars
Lutz, D.; Genzel, R.; Sturm, E. +16 more
We report the results from a comprehensive study of 74 ultraluminous infrared galaxies (ULIRGs) and 34 Palomar-Green (PG) quasars within z ~ 0.3 observed with the Spitzer Infrared Spectrograph (IRS). The contribution of nuclear activity to the bolometric luminosity in these systems is quantified using six independent methods that span a range in w…
Resolving the mid-infrared cores of local Seyferts
Vignali, C.; Gilli, R.; Comastri, A. +5 more
We present new photometry of 16 local Seyferts including 6 Compton-thick sources in N-band filters around 12-µm, obtained with the VISIR instrument on the 8-m Very Large Telescope. The near-diffraction-limited imaging provides the least-contaminated core fluxes for these sources to date. Augmenting these with our previous observations and wi…
The Infrared Spectra of Very Large Irregular Polycyclic Aromatic Hydrocarbons (PAHs): Observational Probes of Astronomical PAH Geometry, Size, and Charge
Peeters, Els; Bauschlicher, Charles W., Jr.; Allamandola, Louis J.
The mid-infrared (IR) spectra of six large, irregular polycyclic aromatic hydrocarbons (PAHs) with formulae (C84H24-C120H36) have been computed using density functional theory (DFT). Trends in the dominant band positions and intensities are compared to those of large, compact PAHs as a function of geomet…
Methane and its isotopologues on Saturn from Cassini/CIRS observations
Fletcher, L. N.; Irwin, P. G. J.; Teanby, N. A. +2 more
High spectral resolution observations from the Cassini Composite Infrared Spectrometer [Flasar, F.M., and 44 colleagues, 2004. Space Sci. Rev. 115, 169-297] are analysed to derive new estimates for the mole fractions of CH 4, CH 3D and 13CH 4 of (4.7±0.2)×10, (3.0±0.2)×10 and (5.1±0.2)×10 respectively. T…
Abundant Circumstellar Silica Dust and SiO Gas Created by a Giant Hypervelocity Collision in the ~12 Myr HD172555 System
Bryden, G.; Wyatt, M. C.; Chen, C. H. +4 more
The fine dust detected by infrared (IR) emission around the nearby β Pic analog star HD172555 is very peculiar. The dust mineralogy is composed primarily of highly refractory, nonequilibrium materials, with approximately three quarters of the Si atoms in silica (SiO2) species. Tektite and obsidian lab thermal emission spectra (nonequili…
The dust condensation sequence in red supergiant stars
Eriksson, K.; Hony, S.; Decin, L. +3 more
Context: Red supergiant (RSG) stars exhibit significant mass loss by means of a slow, dense wind. They are often considered to be the more massive counterparts of Asymptotic Giant Branch (AGB) stars. While AGB mass loss is related to their strong pulsations, the RSG are often only weakly variable. This raises the question of whether their wind-dri…
The Extended Environment of M17: A Star Formation History
Bieging, John H.; Kang, Miju; Indebetouw, Rémy +9 more
M17 is one of the youngest and most massive nearby star-formation regions in the Galaxy. It features a bright H II region erupting as a blister from the side of a giant molecular cloud (GMC). Combining photometry from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) with complementary infrared (IR) surveys, we identif…
Strong [CII] emission at high redshift
Maiolino, R.; Meneghetti, M.; De Breuck, C. +3 more
We report the detection of the [Cii]157.74 µm fine-structure line in the lensed galaxy BRI 0952-0115 at z=4.43, using the APEX telescope. This is the first detection of the [Cii] line in a source with L_FIR < 1013~L_⊙ at high redshift. The line is much stronger than previous [Cii] detections at high-z (a factor of 5-8 higher in…
Dust-Bounded Ultraluminous Infrared Galaxies: Model Predictions for Infrared Spectroscopic Surveys
Abel, N. P.; van Hoof, P. A. M.; Satyapal, S. +2 more
The observed faintness of infrared fine-structure line emission along with the warm far-infrared (FIR) colors of ultraluminous infrared galaxies (ULIRGs) is a long-standing problem. In this work, we calculate the line and continuum properties of a cloud exposed to an active galactic nucleus (AGN) and starburst spectral energy distribution. We use …