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The HyGAL Stratospheric Observatory for Infrared Astronomy (SOFIA) legacy program aims at characterizing the interstellar medium in the Milky Way using hydrides, [C II], and [O I] absorption lines with the 2.7 m SOFIA telescope toward…

We study the distribution and dynamics of the circum- and intergalactic medium using a dense galaxy survey covering the field around the Q0107 system, a unique z~1 projected quasar triplet. With full Ly$\alpha$ coverage along all three…

The interstellar medium (ISM) consists of highly ionized and neutral atomic, as well as molecular, components. Knowledge of their distribution is important for tracing the structure and lifecycle of the ISM. Here we determine the properties…

Astrophysics of Galaxies · Physics 2016-05-25 W. D. Langer , P. F. Goldsmith , J. L. Pineda

We present a comparative analysis of interstellar hydrogen (HI) and potassium (KI) absorption from the radio and optical surveys, GASKAP and GALAH, to study the physical and kinematic properties of the cold interstellar medium (ISM) in the…

The physical conditions of the circumgalactic medium are probed by intervening absorption-line systems in the spectrum of background quasi-stellar objects out to the epoch of cosmic reionization. A correlation between the ionization state…

This investigation is aimed at clarifying the nature of the interstellar gas seen in absorption against bright O and B stars. Towards this end we have obtained for the first time HI absorption spectra towards radio sources very close to the…

Astrophysics · Physics 2007-05-23 Jayadev Rajagopal , G. Srinivasan , K. S. Dwarakanath

We present a study exploring the nature and properties of the Circum-Galactic Medium (CGM) and its connection to the atomic gas content in the interstellar medium (ISM) of galaxies as traced by the HI 21cm line. Our sample includes 45 low-z…

Until now the known sources in the Galactic center with sufficiently smooth spectra and of sufficient brightness to be suitable for high resolution infrared absorption spectroscopy of interstellar gas occupied a narrow range of longitudes,…

Astrophysics of Galaxies · Physics 2015-05-14 T. R. Geballe , T. Oka

We present ultra-high resolution (0.32 km/s) spectra obtained with the 3.9m Anglo-Australian Telescope (AAT) and Ultra-High-Resolution Facility (UHRF), of interstellar NaI D1, D2, Ca II K, K I and CH absorption toward two high galactic…

Astrophysics · Physics 2009-10-30 M. S. Sahu , J. C. Blades , L. He , D. Hartmann , M. J. Barlow , I. A. Crawford

A detailed study of the absorbing molecular clouds towards the radio source PKS1413+135, at a redshift z=0.247, is reported. Physical conditions are derived for the molecular gas in the frame work of two models: a homogeneous multicomponent…

Astrophysics · Physics 2007-05-23 Tommy Wiklind , Francoise Combes

The [CII] fine--structure line at 158um is an excellent tracer of the warm diffuse gas in the ISM and the interfaces between molecular clouds and their surrounding atomic and ionized envelopes. Here we present the initial results from…

We present a quantitative model for the infrared emission from dust in the diffuse interstellar medium. The model consists of a mixture of amorphous silicate grains and carbonaceous grains, each with a wide size distribution ranging from…

Astrophysics · Physics 2008-11-26 Aigen Li , B. T. Draine

A simple analytic model is presented to predict the near-IR H2 fluorescent line intensities emitted by diffuse interstellar clouds with a Plummer density profile. It is applicable to sightlines where (1) the column densities of H and H2…

Astrophysics of Galaxies · Physics 2024-10-15 David A. Neufeld

New optical spectra of Ca II and Na I toward HD 72127AB provide additional evidence for both spatial and temporal variations in the complex interstellar absorption along the two sight lines; archival UV spectra yield information on the…

Astrophysics · Physics 2009-11-13 Daniel E. Welty , Thuso Simon , L. M. Hobbs

Since molecules are ubiquitous in space, the study of the 'Molecular Universe' could unfold the mystery of the existing Interstellar medium. Star formation is linked to the chemical evolution processes. Thus, an analysis of the formation of…

Astrophysics of Galaxies · Physics 2024-05-29 Bratati Bhat

We report on the discovery of correlations between dust and CO gas tracers of the 0.1-10 au region in planet-forming disks around young intermediate-mass stars. The abundance of refractory elements on stellar photospheres decreases as the…

Earth and Planetary Astrophysics · Physics 2018-02-07 A. Banzatti , A. Garufi , M. Kama , M. Benisty , S. Brittain , K. M. Pontoppidan , J. T. Rayner

We wish to relate the degree scale structure of galactic diffuse clouds to sub-arcsecond atomic and molecular absorption spectra obtained against extragalactic continuum background sources. To do this, we used the ARO 12m telescope to map…

Astrophysics of Galaxies · Physics 2015-06-04 H. S. Liszt , J. Pety

We present high resolution (R ~ 4 km/s) absorption measurements of the interstellar NaI and CaII lines measured towards 14 early-type stars of distance 123 pc - 1650 pc, located in the direction of the Ara OB1 stellar cluster. The line…

Astrophysics · Physics 2009-06-23 Christopher D. Henderson , Barry Y. Welsh , John B. Hearnshaw

Molecules that trace the high-density regions of the interstellar medium have been observed in (ultra-)luminous (far-)infrared galaxies, in order to initiate multiple-molecule multiple-transition studies to evaluate the physical and…

Astrophysics · Physics 2009-11-13 W. A. Baan , C. Henkel , A. F. Loenen , A. Baudry , T. Wiklind

From new observations and literature data we investigate the presence of HI, dust, and optical cores in the central kiloparsec of low-power radio galaxies. The goal of this pilot study is to identify physical relations between these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Ilse M. van Bemmel , Raffaella Morganti , Tom Oosterloo , Gustaaf van Moorsel