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We present a systematic study of deuterated molecular hydrogen (HD) at high redshift, detected in absorption in the spectra of quasars. We present four new identifications of HD lines associated with known $\rm H_2$-bearing Damped…

Astrophysics of Galaxies · Physics 2021-06-30 D. N. Kosenko , S. A. Balashev , P. Noterdaeme , J. -K. Krogager , R. Srianand , C. Ledoux

We report an accurate distance of d = 10+/-2.5kpc to the high-velocity cloud Complex C. Using high signal-to-noise Keck/HIRES spectra of two horizontal-branch stars, we have detected CaII K absorption lines from the cloud. Significant…

Astrophysics · Physics 2009-11-13 C. Thom , J. E. G. Peek , M. E. Putman , Carl Heiles , K. M. G. Peek , R. Wilhelm

The source of fluorine is not well understood, although core-collapse supernovae, Wolf-Rayet stars, and asymptotic giant branch stars have been suggested. A search for evidence of the nu process during Type II supernovae is presented.…

Astrophysics · Physics 2009-11-10 S. R. Federman , Yaron Sheffer , David L. Lambert , V. V. Smith

We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. We explore various galactic interstellar medium environments, including cosmic-ray ionization…

Astrophysics of Galaxies · Physics 2021-01-20 Thomas G. Bisbas , Jonathan C. Tan , Kei E. I. Tanaka

Many recent models consider the structure of individual interstellar medium (ISM) clouds as a way to explain observations of large parts of galaxies. To compare such models to observations, one must understand how to translate between…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Adam K. Leroy , Cheoljong Lee , Andreas Schruba , Alberto Bolatto , Annie Hughes , Jerome Pety , Karin Sandstrom , Eva Schinnerer , Fabian Walter

We investigate interstellar absorption from molecular hydrogen (H_2) and metals in an intermediate-velocity cloud (IVC) in the direction of the LMC star Sk -68 80 (HD 36521), based on data from the Far Ultraviolet Spectroscopic Explorer…

Astrophysics · Physics 2011-05-23 P. Richter , K. R. Sembach , J. C. Howk

This paper provides a general reference for deriving the ionizations and metal abundances for absorption-line clouds in photoionization equilibrium with a QSO spectrum. The results include a quantitative assessment of the theoretical…

Astrophysics · Physics 2009-10-30 Fred Hamann

We present measurements of interstellar H_2 absorption lines in the continuum spectra of seven early-type stars in the Galactic disk at distances between 1 and 4 kpc. Five of these stars provide lines of sight through the Sagittarius spiral…

Astrophysics · Physics 2009-10-30 W. Van Dyke Dixon , Mark Hurwitz , Stuart Bowyer

We have recently identified several high velocity (V < -100 km/s) clouds in the directions of Mrk 509 and PKS 2155-304 that have unusual ionization properties. The clouds exhibit strong C IV absorption with little or no detectable low ion…

Astrophysics · Physics 2009-10-30 Kenneth R. Sembach , Blair D. Savage , Limin Lu , Edward M. Murphy

A numerical calculation of properties of finite absorbers and of intergalactic medium based on photoionization equilibrium is performed to confront alternative UV sources in addition to quasars. It is seen that a spectrum including a large…

Astrophysics · Physics 2010-11-30 L. Masperi , S. Savaglio

We perform a homogeneous analysis of the Fe/Ni abundance ratio in eight Galactic planetary nebulae (PNe) and three Galactic H II regions that include the Orion nebula, where we study four nebular zones and one shocked region. We use [Fe…

Solar and Stellar Astrophysics · Physics 2016-01-20 Gloria Delgado-Inglada , Adal Mesa-Delgado , Jorge García-Rojas , Mónica Rodríguez , César Esteban

We present a new model to compute the effects of dust on the integrated spectral properties of galaxies, based on an idealized prescription of the main features of the interstellar medium (ISM). The model includes the ionization of HII…

Astrophysics · Physics 2009-10-31 S. Charlot , S. Michael Fall

We present Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope observations of high, intermediate, and low ion absorption in high-velocity cloud Complex C along the lines of sight toward five active galaxies. Our purpose is to…

We present high-resolution spectroscopy of the neon K-shell and iron L-shell interstellar absorption edges in nine X-ray binaries using the High Energy Transmission Grating Spectrometer (HETGS) onboard the Chandra X-ray Observatory. We…

We have obtained high resolution (FWHM = 4.4 km/s) Keck spectra of images A and C of the gravitationally lensed QSO Q1422+231. The images are separated by 1.3" on the sky. In an absorption system at z = 3.538 gas column density variations…

Astrophysics · Physics 2007-05-23 Michael Rauch , Wallace L. W. Sargent , Thomas A. Barlow

We use very deep spectra obtained with the Ultraviolet-Visual Echelle Spectrograph in the Very Large Telescope in order to determine the physical conditions, the chemical abundances and the iron depletion factors of four H II regions of the…

Astrophysics of Galaxies · Physics 2017-01-11 G. Domínguez-Guzmán , M. Rodríguez , C. Esteban , J. García-Rojas

We present an extended analysis of the high dispersion IUE spectra of SN 1993J in M81, based on the improved data in the IUE final archive. Eight interstellar absorption components can be identified in the velocity range from -200 km/s to…

Astrophysics · Physics 2007-05-23 Ole Marggraf , Klaas S. de Boer

We show 21-cm line profiles in the direction of stars and extragalactic objects, lying projected on high- and intermediate-velocity clouds (HVCs and IVCs). About half of these are from new data obtained with the Effelsberg 100-m telescope,…

Astrophysics · Physics 2009-11-06 B. P. Wakker , P. M. W. Kalberla , H. van Woerden , K. S. de Boer , M. E. Putman

We study the dust present in 56 Galactic planetary nebulae (PNe) through their iron depletion factors, their C/O abundance ratios (in 51 objects), and the dust features that appear in their infrared spectra (for 33 objects). Our sample…

Solar and Stellar Astrophysics · Physics 2015-06-18 Gloria Delgado-Inglada , Mónica Rodríguez

We have obtained spectra of 102 red giant branch (RGB) stars in the Leo I dwarf spheroidal galaxy (dSph) and 74 RGB stars in the Leo II dSph using LRIS on the Keck I 10-meter Telescope. We report on the calcium abundances [Ca/H] derived…

Astrophysics · Physics 2008-11-26 Tammy L. Bosler , Tammy A. Smecker-Hane , Peter B. Stetson
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