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Related papers: High-Velocity Cloud Complex C: Galactic Fuel or ga…

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Many high velocity HI clouds (HVCs) are now believed to be scattered throughout the Galactic halo on scales of tens of kiloparsecs. Some of these clouds appear to contain substantial HI masses (>10^6 Msun). It has been suggested that these…

Astrophysics · Physics 2009-10-31 Geraint F. Lewis , Joss Bland-Hawthorn , Brad C. Gibson , Mary E. Putman

Very sensitive HI 21cm observations have been made in 860 directions at dec >= -43deg in search of weak, Galactic, high-velocity HI emission lines at moderate and high Galactic latitudes. One-third of the observations were made toward…

Astrophysics · Physics 2009-11-07 Felix J. Lockman , Edward M. Murphy , Sara Petty-Powell , Vincent J. Urick

Infrared absorption lines of H3+, including the metastable R(3,3)l line, have been observed toward eight bright infrared sources associated with hot and massive stars located in and between the Galactic Center Cluster and the Quintuplet…

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

We address the spatial scale, ionization structure, mass and metal content of gas at the Milky Way disk-halo interface detected as absorption in the foreground of seven closely-spaced, high-latitude halo blue horizontal branch stars (BHBs)…

To understand the impact of low metallicities on giant molecular cloud (GMC) structure, we compare far infrared dust emission, CO emission, and dynamics in the star-forming complex N83 in the Wing of the Small Magellanic Cloud. Dust…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-12 A. K. Leroy , A. Bolatto , C. Bot , C. W. Engelbracht , K. Gordon , F. P. Israel , M. Rubio , K. Sandstrom , S. Stanimirović

Archival Goddard High Resolution Spectrograph low-resolution spectra of NGC 1705, with wavelength ranges 1170.3 to 1461.7 A and 1453.5 to 1740.1 A and a velocity resolution of about 100 km\s, have been used to derive the velocity structure…

Astrophysics · Physics 2009-10-30 M. S. Sahu , J. Chris Blades

Ams: We study the 12C/13C isotopic ratio in the disk of the central molecular zone and in the halo to trace gas accretion toward the Galactic center region in the Milky Way. Methods: Using the IRAM 30m telescope, we observe the J=1-0…

Astrophysics of Galaxies · Physics 2015-05-19 D. Riquelme , M. A. Amo-Baladron , J. Martin-Pintado , R. Mauersberger , S. Martin , L. Bronfman

We present the results of a galaxy-wide study of molecular gas and star formation in a sample of 76 HII regions in the nearby spiral galaxy NGC 300. We have measured the molecular gas at 250 pc scales using pointed CO(J=2-1) observations…

Astrophysics of Galaxies · Physics 2015-06-19 Christopher M. Faesi , Charles J. Lada , Jan Forbrich , Karl Menten , Herve Bouy

In the Galactic halo, metal-bearing Galactic halo material mixes into high velocity clouds (HVCs) as they hydrodynamically interact. This interaction begins long before the clouds completely dissipate and long before they slow to the…

Astrophysics of Galaxies · Physics 2014-11-19 Jeffrey A. Gritton , Robin L. Shelton , Kyujin Kwak

Neutral atomic hydrogen (HI) gas in interstellar space is largely organized into filaments, loops, and shells, the most prominent of which are "supershells". These gigantic structures requiring $\gtrsim 3 \times 10^{52}$ erg to form are…

Hot, million degree gas appears to pervade the Milky way halo, containing a large fraction of the Galactic missing baryons. This circumgalactic medium (CGM) is probed effectively in X-rays, both in absorption and in emission. The CGM also…

Astrophysics of Galaxies · Physics 2017-03-08 Anjali Gupta , Smita Mathur , Yair Krongold

We now have mounting evidences that the circumgalactic medium (CGM) of galaxies is polluted with metals processed through stars. The fate of these metals is however still an open question and several findings indicate that they remain…

Astrophysics of Galaxies · Physics 2018-07-31 Celine Peroux , Hadi Rahmani , Fabrizio Arrigoni Battaia , Ramona Augustin

Optical emission lines provide an important new window on the HVCs. Recent studies of the H-alpha line reveal that ionized gas is pervasively associated with the neutral hydrogen in HVCs. The Wisconsin H-Alpha Mapper (WHAM) instrument has…

Astrophysics · Physics 2007-05-23 S. L. Tufte , R. J. Reynolds , L. M. Haffner

Compact high-velocity clouds (CHVCs) are the most distant of the HVCs in the Local Group model and would have HI volume densities of order 0.0003/cm^3. Clouds with these volume densities and the observed neutral hydrogen column densities…

Astrophysics · Physics 2009-11-07 Philip R. Maloney , Mary E. Putman

We report on the discovery of cool gas inflow toward six star-forming galaxies with redshifts z ~ 0.35 - 1. Analysis of MgII and FeII resonance-line absorption in Keck/LRIS spectroscopy of this sample reveals velocity shifts of 80 - 200…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Kate H. R. Rubin , J. Xavier Prochaska , David C. Koo , Andrew C. Phillips

We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We…

Astrophysics · Physics 2009-11-10 Rekhesh Mohan , K. S. Dwarakanath , G. Srinivasan

A model is proposed for determining the distances to falling interstellar clouds in the galactic halo by measuring the cloud velocity and column density and assuming a model for the vertical density distribution of the Galactic interstellar…

Astrophysics · Physics 2009-10-28 Robert A. Benjamin , Laura Danly

Aims. We aim to investigate the ionisation conditions and distances of Galactic high-velocity clouds (HVCs) in the Galactic halo and beyond in the direction of the Local Group (LG) barycentre and anti-barycentre, by studying spectral data…

Astrophysics of Galaxies · Physics 2019-06-26 Sietske J. D. Bouma , Philipp Richter , Cora Fechner

We detect high-velocity absorbing gas using Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer medium resolution spectroscopy along two high-latitude AGN sight lines (Mrk 1383 and PKS 2005-489) above and below the Galactic…