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We present 21-cm absorption measurements towards 12 radio continuum sources with previously identified thermally-unstable warm neutral medium (WNM). These observations were obtained with the Expanded Very Large Array (EVLA) and were…

Astrophysics of Galaxies · Physics 2015-05-20 Ayesha Begum , Snezana Stanimirovic , W. M. Goss , Carl Heiles , Anthony S. Pavkovich , Patrick Hennebelle

Interstellar ices are largely composed of frozen water. It is important to derive fundamental parameters for H$_2$O ice such as absorption and scattering opacities for which accurate complex refractive indexes are needed. The primary goal…

Instrumentation and Methods for Astrophysics · Physics 2023-12-20 W. R. M. Rocha , M. G. Rachid , M. K. McClure , J. He , H. Linnartz

Solid O2 has been proposed as a possible reservoir for oxygen in dense clouds through freeze-out processes. The aim of this work is to characterize quantitatively the physical processes that are involved in the desorption kinetics of CO-O2…

Astrophysics · Physics 2009-11-13 K. Acharyya , G. W. Fuchs , H. J. Fraser , E. F. van Dishoeck , H. Linnartz

We use spectroscopic data from HST and FUSE to study the wide range of ionization states of the "highly ionized high-velocity clouds". Studied extensively in OVI absorption, these clouds are usually assumed to be infalling gas in the…

Astrophysics · Physics 2009-11-10 J. A. Collins , J. M. Shull , M. L. Giroux

We present a simple, largely empirical but physically motivated model to interpret the mid- and far-infrared spectral energy distributions of galaxies consistently with the emission at ultraviolet, optical and near-infrared wavelengths. Our…

Astrophysics · Physics 2009-11-13 Elisabete da Cunha , Stephane Charlot , David Elbaz

The presence of a ``warm absorber'' was first suggested to explain spectral variability in an X-ray spectrum of the radio-quiet QSO MR2251-178. A unified picture, in which X-ray warm absorbers and ``intrinsic'' UV absorbers are the same,…

Astrophysics · Physics 2007-05-23 E. M. Monier , S. Mathur , B. Wilkes , M. Elvis

Using very high resolution (lambda / Dlambda ~ 95000) 4.7 micron fundamental and 2.3 micron overtone ro-vibrational CO absorption spectra obtained with the CRIRES infrared spectrometer on the Very Large Telescope (VLT), we report detections…

Earth and Planetary Astrophysics · Physics 2009-07-24 Rachel L. Smith , Klaus M. Pontoppidan , Edward D. Young , Mark R. Morris , Ewine F. van Dishoeck

Quasar absorption-line studies in the ultraviolet (UV) can uniquely probe the nature of the multiphase cool-warm (10^4 < T < 10^6 K) gas in and around galaxy clusters, promising to provide unprecedented insights into 1) interactions between…

Astrophysics of Galaxies · Physics 2019-10-23 Iryna S. Butsky , Joseph N. Burchett , Daisuke Nagai , Michael Tremmel , Thomas R. Quinn , Jessica K. Werk

The intensity of the far-ultraviolet (FUV; 6-13.6 eV) interstellar radiation field (ISRF) in galaxies determines the thermal and chemical evolution of the neutral interstellar gas and is key for interpreting extragalactic observations and…

Astrophysics of Galaxies · Physics 2020-11-11 Shmuel Bialy

We present the first localized detections of the cold neutral medium (CNM) in IC10, offering a rare view of dense atomic gas in a low-metallicity (0.27 solar metallicity) dwarf galaxy. As a low-metallicity starburst, IC10's interstellar…

We present measurements of the H I spin temperatures (T_s) of the Cold Neutral Medium (CNM) towards radio sources that are closely aligned with stars for which published H_2 ortho-para temperatures (T_{01}) are available from UV…

Astrophysics · Physics 2007-05-23 Nirupam Roy , Jayaram N. Chengalur , Raghunathan Srianand

H$_{\rm I}$ 21-cm and $^{12}$CO 2.6-mm line emissions respectively trace the atomic and molecular gas phases, but they miss most of the opaque H$_{\rm I}$ and diffuse H$_2$ present in the Dark Neutral Medium (DNM) at the transition between…

High Energy Astrophysical Phenomena · Physics 2018-03-28 Q. Remy , I. A. Grenier , D. J. Marshall , J. M. Casandjian

The standard model of cosmic ray heating-induced desorption of interstellar ices is based on a continuous representation of the sporadic desorption of ice mantle components from classical (0.1 micron) dust grains. This has been re-evaluated…

Solar and Stellar Astrophysics · Physics 2022-08-17 Jonathan M. C. Rawlings

Medium resolution (lambda/Delta lambda = 5000-10000) VLT-ISAAC M-band spectra are presented of 39 young stellar objects in nearby low-mass star forming clouds showing the 4.67 micron stretching vibration mode of solid CO. By taking…

Far-UV observations in and near the Hubble Deep Fields demonstrate that the Space Telescope Imaging Spectrograph (STIS) can potentially obtain unique and precise measurements of the diffuse far-ultraviolet background. Although STIS is not…

Using the statistics of pixel optical depths, we compare HI, CIV and CIII absorption in a set of six high quality z ~ 3-4 quasar absorption spectra to that in spectra drawn from two different state-of-the-art cosmological simulations that…

Astrophysics · Physics 2009-11-10 Anthony Aguirre , Joop Schaye , Lars Hernquist , Scott Kay , Volker Springel , Tom Theuns

Methanol is a common component of interstellar and circumstellar ice mantles and is often used as an evolution indicator in star-forming regions. The observations of gas-phase methanol in the interiors of dense molecular clouds at…

Instrumentation and Methods for Astrophysics · Physics 2016-07-27 Gustavo A. Cruz-Diaz , Rafael Martín-Doménech , Guillermo M. Muñoz Caro , Y. -J. Chen

We present observations of the UV absorption lines in the luminous Seyfert 1 galaxy Mrk 509, obtained with the medium resolution (lambda/Delta-lambda ~ 40,000) echelle gratings of the Space Telescope Imaging Spectrograph on the Hubble Space…

The need to characterize ices coating dust grains in dense interstellar clouds arises from the importance of ice morphology in facilitating the diffusion and storage of radicals and reaction products in ices, a well-known place for the…

Instrumentation and Methods for Astrophysics · Physics 2019-06-26 Jiao He , Aspen R. Clements , SM Emtiaz , Francis Toriello , Robin T. Garrod , Gianfranco Vidali

We report on the properties of LISM O VI absorption observed with 20 km/s resolution FUSE observations of 39 white dwarfs (WDs) ranging in distance from 37 to 230 pc with a median distance of 109 pc. LISM O VI is detected with >2sigma…

Astrophysics · Physics 2009-11-11 Blair D. Savage , Nicholas Lehner
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