English
Related papers

Related papers: Are Compact High-Velocity Clouds Extragalactic Obj…

200 papers

A set of HI sources extracted from the north Galactic polar region by the ongoing ALFALFA survey has properties that are consistent with the interpretation that they are associated with isolated minihalos in the outskirts of the Local Group…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Riccardo Giovanelli , Martha P. Haynes , Brian R. Kent , Elizabeth K. Adams

High-velocity atomic clouds in the Galactic center have attracted significant attention due to their enigmatic formation process, which is potentially linked to the starburst or supermassive black hole activities in the region. Further, the…

Astrophysics of Galaxies · Physics 2023-12-27 Mengfei Zhang , Miao Li

(Abridged) We present a new high-resolution (7 km/s FWHM) echelle spectrum of 3C 351 obtained with STIS. 3C 351 lies behind the low-latitude edge of high-velocity cloud Complex C, and the new spectrum provides accurate measurements of O I,…

We report the results of a photometric search for giant stars associated with the cores of four high velocity clouds (HVCs) -- two of which are compact HVCs -- using the Las Campanas Du Pont 2.5 meter and Cerro Tololo Blanco 4 meter…

Astrophysics · Physics 2009-11-10 M. H. Siegel , S. R. Majewski , C. Gallart , S. Sohn , W. E. Kunkel , R. Braun

The Magellanic Stream (MS) is a well-resolved gaseous tail originating from the Magellanic Clouds. Studies of its physical properties and chemical composition are needed to understand its role in Galactic evolution. We investigate the…

Astrophysics of Galaxies · Physics 2015-06-23 Nimisha Kumari , Andrew J. Fox , Jason Tumlinson , Christopher Thom , Tobias Westmeier , Justin Ely

We have observed a 3 degree x 3 degree area centered on the M81/M82 group of galaxies using the Robert C. Byrd Green Bank Telescope (GBT) in a search for analogs to the High Velocity Clouds (HVCs) of neutral hydrogen found around our…

We study the physical conditions, elemental abundances, and kinematics of the high-velocity clouds (HVCs) along the sight lines toward active galaxies HE0226-4110 and PG0953+414 using Hubble Space Telescope Imaging Spectrograph and Far…

In this paper we use a number of observations to construct an integrated picture of the ionisation in the interiors of quiescent warm opaque interstellar clouds and in the intercloud medium (ICM) outside dense HII regions and hot dilute…

Astrophysics · Physics 2009-10-30 D. W. Sciama

We report the first determination of a distance bracket for the high-velocity cloud (HVC) complex C. Combined with previous measurements showing that this cloud has a metallicity of 0.15 times solar, these results provide ample evidence…

A population of molecular clouds with a significantly greater scale height than that of Giant Molecular Clouds has been identified by examining maps of the latitude distribution of the $^{12}CO(1-0)$ emission in the first quadrant of the…

Astrophysics · Physics 2009-10-22 Sangeeta Malhotra

We present high resolution (R = 114,000) ultraviolet measurements of the interstellar absorption line profiles of the CIV (1550 A) high ionization doublet recorded towards the nearby B2Ve star HD 158427 (d~74pc). These data, which were…

Astrophysics of Galaxies · Physics 2015-05-18 Barry Y. Welsh , Jonathan Wheatley , Oswald H. W. Siegmund , Rosine Lallement

We develop a new method to constrain the physical conditions in the cool (~10^4 K) circumgalactic medium (CGM) from measurements of ionic column densities, by assuming that the cool CGM spans a large range of gas densities and that small…

Astrophysics of Galaxies · Physics 2016-10-26 Jonathan Stern , Joseph F. Hennawi , J. Xavier Prochaska , Jessica K. Werk

The circumgalactic medium (CGM) remains one of the least constrained components of galaxies and as such has significant potential for advancing galaxy formation theories. In this work, we vary the extragalactic ultraviolet background for a…

Astrophysics of Galaxies · Physics 2016-08-31 Lauren Corlies , David Schiminovich

We analyze circumgalactic medium (CGM) in a suite of high-resolution cosmological re-simulations of a Milky-Way size galaxy and show that CGM properties are quite sensitive to details of star formation--feedback loop modelling. The…

Astrophysics of Galaxies · Physics 2016-03-09 Cameron J. Liang , Andrey V. Kravtsov , Oscar Agertz

High-Velocity Clouds (HVCs) are a major fuel reservoir for star formation in the Galactic disk. Determining their origin and kinematics is thus crucial for understanding Galactic evolution. In this paper, we employ simple test-particle…

Astrophysics of Galaxies · Physics 2026-04-28 Izumi Seno , Shu-ichiro Inutsuka , Jiro Shimoda

The evidence for locating the High Velocity Clouds in the Local Group is summarized and evaluated. Recent measurements of the H$\alpha$ surface brightness and metallicity of a number of HVCs appear to be fatal to the Galactic fountain as a…

Astrophysics · Physics 2007-05-23 Leo Blitz

We report the detection of a peculiar molecular cloud, CO 0.02-0.02, lying about 5' Galactic-east from the center of the Galaxy. (12)CO images taken with NRO 45 m telescope showed that it is relatively compact (about 3x4 pc^2) as well as…

Astrophysics · Physics 2009-10-31 T. Oka , G. J. White , T. Hasegawa , F. Sato , M. Tsuboi , A. Miyazaki

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…

Using the IRAM 30m telescope two molecular structures have been detected which cover very small areas, FWHM<1'. The clouds have velocities of v_lsr~5kms and linewidth of dv~0.8km/s; thus they belong most likely to the Milky Way. Applying…

Astrophysics · Physics 2009-11-07 Andreas Heithausen

Hypervelocity stars (HVS) traverse the Galaxy from the central black hole to the outer halo. We show that the Galactic potential within 200 pc acts as a high pass filter preventing low velocity HVS from reaching the halo. To trace the…

Astrophysics · Physics 2009-11-13 S. J. Kenyon , B. C. Bromley , M. J. Geller , W. R. Brown