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We have complemented existing observations of HI absorption with new observations of HCO$^+$, C$_2$H, HCN, and HNC absorption from the Atacama Large Millimeter/submillimeter Array (ALMA) and the Northern Extended Millimeter Array (NOEMA) in…

Molecular hydrogen clouds are a key component of the interstellar medium because they are the birthplaces for stars. They are embedded in atomic gas that pervades the interstellar space. However, the details of how molecular clouds assemble…

We have measured the profiles of the Ca II H and K chromospheric emission lines in 147 main sequence stars of spectral type M5-K7 (0.30-0.55 solar masses) using multiple high resolution spectra obtained during six years with the HIRES…

Astrophysics · Physics 2009-11-11 Emily Rauscher , Geoffrey W. Marcy

We have determined column densities of H I and/or H_2 for sight lines in the Magellanic Clouds from archival HST and FUSE spectra of H I Lyman-alpha and H_2 Lyman-band absorption. Together with some similar data from the literature, we now…

Astrophysics of Galaxies · Physics 2015-06-03 Daniel E. Welty , Rui Xue , Tony Wong

We investigate the environment of the infrared dust bubble S51 and search for evidence of triggered star formation in its surroundings. We performed a multiwavelength study of the region around S51 with data taken from large-scale surveys:…

Astrophysics of Galaxies · Physics 2012-07-03 Chuan Peng Zhang , Jun Jie Wang

The cycling of carbon between its ionized, atomic, and molecular phases shapes the chemical compositions and physical conditions of the interstellar medium (ISM). However, ground-based studies of the full carbon cycle have been limited by…

The spatial distribution of neutral hydrogen (H I) emission is a powerful probe of interstellar medium physics. The small-scale structure in H I channel maps is often assumed to probe the velocity field rather than real density structures.…

Astrophysics of Galaxies · Physics 2020-01-08 J. E. G. Peek , S. E. Clark

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

We discuss the absorption due to various constituents of the interstellar medium of M82 seen in moderately high resolution, high signal-to-noise ratio optical spectra of SN 2014J. Complex absorption from M82 is seen, at velocities 45 $\le$…

Astrophysics of Galaxies · Physics 2015-06-19 Daniel E. Welty , Adam M. Ritchey , Julie A. Dahlstrom , Donald G. York

This paper investigates small-scale structures of dense gas and dust around the low-mass protostellar binary NGC1333-IRAS2 using millimeter-wavelength aperture-synthesis observations from the OVRO and BIMA interferometers. The detected 3 mm…

In studying the interstellar medium (ISM) and Galactic cosmic rays (CRs), uncertainty of the interstellar gas density has always been an issue. To overcome this difficulty, we used a component decomposition of the 21-cm HI line emission and…

High Energy Astrophysical Phenomena · Physics 2022-08-31 T. Mizuno , K. Hayashi , J. Metzger , I. V. Moskalenko , E. Orlando , A. W. Strong , H. Yamamoto

An extensive modelling of CO line emission from the circumstellar envelopes around a number of carbon stars is performed. By combining radio observations and infrared observations obtained by ISO the circumstellar envelope characteristics…

Astrophysics · Physics 2009-11-07 F. L. Schoeier , N. Ryde , H. Olofsson

We present a study of the detectability of CO molecules in the Galactic interstellar medium using high-resolution X-ray spectra obtained with the XMM-Newton Reflection Grating Spectrometer. We analyzed 10 bright low mass X-ray binaries…

High Energy Astrophysical Phenomena · Physics 2016-07-27 Katerine Joachimi , Efraín Gatuzz , Javier A. García , Timothy R. Kallman

Recent studies of the molecular medium in nearby galaxies have provided mounting evidence that the molecular gas can exist in two phases: one that is clumpy and organized as molecular clouds and another one that is more diffuse. This last…

Astrophysics of Galaxies · Physics 2015-06-23 Anahi Caldu-Primo , Andreas Schruba , Fabian Walter , Adam Leroy , Alberto D. Bolatto , Stuart Vogel

The intergalactic medium at redshifts 2--6 can be studied observationally through the absorption features it produces in the spectra of background quasars. Most of the UV-absorption lines arise in mildly overdense regions, which can be…

Astrophysics · Physics 2007-05-23 Tom Theuns

With the recent discovery of transiting planetary material around WD 1145+017, a critical target has been identified that links the evolution of planetary systems with debris disks and their accretion onto the star. We present a series of…

Earth and Planetary Astrophysics · Physics 2017-04-19 Seth Redfield , Jay Farihi , P. Wilson Cauley , Steven G. Parsons , Boris T. Gaensicke , Girish Duvvuri

We present an analysis of interstellar absorption lines in high-resolution optical echelle spectra of SS Cyg obtained during an outburst in 2013 June and in archival Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer data.…

Astrophysics of Galaxies · Physics 2018-06-07 Adam M. Ritchey , George Wallerstein , Jean McKeever

We map the distribution and properties of the Milky Way's interstellar medium as traced by diffuse interstellar bands (DIBs) detected in near-infrared stellar spectra from the SDSS-III/APOGEE survey. Focusing exclusively on the strongest…

The HI line at 21 cm is a tracer of circumstellar matter around AGB stars, and especially of the matter located at large distances (0.1-1 pc) from the central stars. It can give unique information on the kinematics and on the physical…

Solar and Stellar Astrophysics · Physics 2011-09-27 E. Gerard , T. Le Bertre , Y. Libert

We report on the detection with the Infrared Space Observatory (ISO) of a molecular band at 57.5 microns (174 cm^{-1}) in carbon-rich evolved stars and in Sgr B2. Taking into account the chemistry of these objects the most likelihood…

Astrophysics · Physics 2009-11-07 J. Cernicharo , J. R. Goicoechea , Y. Benilan