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Related papers: An Accurate Distance to High-Velocity Cloud Comple…

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We discuss the interstellar absorption from many atomic and molecular species seen in high-resolution $HST$/STIS UV and high-S/N optical spectra of the moderately reddened B3-5~V star HD~62542. This remarkable sight line exhibits both very…

Astrophysics of Galaxies · Physics 2020-07-08 Daniel E. Welty , Paule Sonnentrucker , Theodore P. Snow , Donald G. York

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

High-velocity clouds (HVCs) are neutral or ionised gas clouds in the vicinity of the Milky Way that are characterised by high radial velocities inconsistent with participation in the regular rotation of the Galactic disc. Previous attempts…

Astrophysics of Galaxies · Physics 2017-12-05 Tobias Westmeier

We present new high resolution (R>50,000) absorption measurements of the NaI doublet (5889 - 5895A) along 482 nearby sight-lines, in addition to 807 new measurements of the CaII K (3933A) absorption line. We have combined these new data…

Astrophysics of Galaxies · Physics 2015-05-14 Barry Y. Welsh , Rosine Lallement , Jean-Luc Vergely , Severine Raimond

The Complex of Local Interstellar Clouds (CLIC) is a relatively tight grouping of low density, warm, partially ionized clouds within about 15 pc of the Solar System. The Local Interstellar Cloud (LIC) is the cloud observed on most lines of…

Astrophysics · Physics 2009-06-23 Jonathan D. Slavin

We searched for 21-cm absorption associated with the z_abs = 1.3647 absorption system toward PKS 0237-233 using the GMRT. A high quality UVES spectrum shows that C I and C I* are detected at this redshift together with C II*, Mg I, Mg II,…

Astrophysics · Physics 2008-11-26 Raghunathan Srianand , Neeraj Gupta , Patrick Petitjean

We used multi-band observations by the Herschel Space Observatory to study the dust emission properties of the nearby spiral galaxy NGC 300. We compiled a first catalogue of the population of giant dust clouds (GDCs) in NGC 300 and give an…

Astrophysics of Galaxies · Physics 2018-05-02 M. Riener , C. M. Faesi , J. Forbrich , C. J. Lada

We have obtained Keck HIRES spectra of three images of the gravitationally lensed QSO 2237+0305 to study low ionization absorption systems and their differences in terms of projected velocity and column density across the lines of sight. We…

Astrophysics · Physics 2009-11-07 M. Rauch , W. L. W. Sargent , T. A. Barlow , R. A. Simcoe

The vertical distribution of cold neutral hydrogen (HI) clouds is a constraint on models of the structure, dynamics, and hydrostatic balance of the interstellar medium. In 1978, Crovisier pioneered a method to infer the vertical…

Astrophysics of Galaxies · Physics 2024-03-29 Trey V. Wenger , Daniel R. Rybarczyk , Snežana Stanimirović

The cold neutral medium (CNM) is where neutral atomic hydrogen (HI) is converted into molecular clouds, so the structure and kinematics of the CNM are key drivers of galaxy evolution. Here we provide new constraints on the vertical…

Astrophysics of Galaxies · Physics 2024-09-30 Daniel R. Rybarczyk , Trey V. Wenger , Snezana Stanimirović

We present deep HI observations of the compact high-velocity cloud HVC125+41-207 using the 100-m Effelsberg telescope. Our goal was in particular to study the warm neutral medium (WNM) in detail. The Effelsberg data reveal a two phase…

Astrophysics · Physics 2009-11-06 C. Bruens , J. Kerp , A. Pagels

High-velocity clouds (HVCs), which are gas clouds moving at high velocity relative to the galactic disk, may play a critical role in galaxy evolution, potentially supplying gas to the disk and triggering star formation. In this study, we…

Astrophysics of Galaxies · Physics 2025-07-02 Maki Nagata , Fumi Egusa , Fumiya Maeda , Kazuki Tokuda , Kotaro Kohno , Kana Morokuma-Matsui , Jin Koda

Francis & Hewett (1993) identified two 10-Mpc scale regions of the high redshift universe that were seemingly very overdense in neutral hydrogen. Subsequent observations showed that at least one of these gas-rich regions enveloped a cluster…

Astrophysics · Physics 2009-10-31 Paul J. Francis , Greg M. Wilson , Bruce E. Woodgate

In the preceding paper (paper I), we presented HI absorption spectra towards radio sources very close to the lines of sight towards 25 bright stars against which optical absorption spectra had been obtained earlier. In this paper we analyse…

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

On its journey through the Galaxy, the Sun passes through diverse regions of the interstellar medium. High-resolution spectroscopic measurements of interstellar absorption lines in spectra of nearby stars show absorption components from…

A catalog of Southern anomalous-velocity HI clouds at Decl. < +2 deg is presented, based on data from the HI Parkes All-Sky Survey (HIPASS). The improved sensitivity (5sigma: T_B = 0.04 K) and resolution (15.5') of the HIPASS data results…

We investigate the dynamical effects of a molecular cloud complex with a mass of about 10**7 M_sun and a size of a few 100 pc on the vertical distribution of stars and atomic hydrogen gas in a spiral galactic disc. Such massive complexes…

Astrophysics · Physics 2009-11-07 Chanda J. Jog , Chaitra A. Narayan

A recent discovery of two stellar clusters associated with the diffuse high-latitude cloud HRK 81.4-77.8 has important implications for star formation in the Galactic halo. We derive a plausible distance estimate to HRK 81.4-77.8 primarily…

Astrophysics of Galaxies · Physics 2016-05-04 J. Kerp , D. Lenz , T. Roehser

We present a census of neutral gas in the Milky Way disk and halo down to limiting column densities of $N$(HI)$\sim10^{14}$ cm$^{-2}$ using measurements of HI Lyman-series absorption from the Far Ultraviolet Spectroscopic Explorer (FUSE).…

We have studied HI absorption towards three non-thermal filaments (NTFs) Sgr-C, G359.54+0.18 and G359.79+0.17 using the Giant Metrewave Radio Telescope (GMRT). Our study, for the first time, constrains the distance of the Sgr C NTF and the…

Astrophysics · Physics 2009-11-07 Subhashis Roy