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Broad absorption lines (BALs) in quasar spectra are prominent signatures of high-velocity outflows, which might be present in all quasars and could be a major contributor to feedback to galaxy evolution. Studying the variability in these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Daniel M. Capellupo , Fred Hamann , Joseph C. Shields , Jules P. Halpern , Tom A. Barlow

We constrain gas inflow speeds in star-forming galaxies with color gradients consistent with inside-out disk growth. Our method combines new measurements of disk orientation with previously described circumgalactic absorption in background…

Astrophysics of Galaxies · Physics 2020-04-15 Stephanie H. Ho , Crystal L. Martin

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

We determined C, N and alpha-element relative abundances in the gas surrounding six QSOs at an average redshift of < z > ~ 2.4, by studying six narrow associated absorption systems in UVES high-resolution spectra. We found five systems with…

(Abridged) This paper presents the first connections made between two local features in velocity-space found in a survey of M giant stars and stellar spatial inhomogeneities on global scales. Comparison to cosmological, chemodynamical…

Astrophysics of Galaxies · Physics 2015-06-04 Kathryn V. Johnston , Allyson A. Sheffield , Steven R. Majewski , Sanjib Sharma

Based on long baseline (5-7 years) multi-epoch HST/ACS photometry, used previously to measure the proper motion of M31, we present the proper motions (PMs) of 13 main-sequence Milky Way halo stars. The sample lies at an average distance of…

Astrophysics of Galaxies · Physics 2015-06-15 A. J. Deason , R. P. Van der Marel , P. Guhathakurta , S. T. Sohn , T. M. Brown

We model the fastest moving (v_tot > 300 km/s) local (D < 3 kpc) halo stars using cosmological simulations and 6-dimensional Gaia data. Our approach is to use our knowledge of the assembly history and phase-space distribution of halo stars…

Astrophysics of Galaxies · Physics 2019-03-13 Alis J. Deason , Azadeh Fattahi , Vasily Belokurov , Wyn Evans , Robert J. Grand , Federico Marinacci , Rudiger Pakmor

The median observed velocity width v_90 of low-ionization species in damped Ly-alpha systems is close to 90 km/s, with approximately 10% of all systems showing v_90 > 210 km/s at z=3. We show that a relative shortage of such high-velocity…

Based on the first Gaia data release and spectroscopy from the LAMOST Data Release 4, we study the kinematics and chemistry of the local halo stars. The halo stars are identified kinematically with a relative speed of at least 220 km…

Astrophysics of Galaxies · Physics 2018-08-22 Cuihua Du , Hefan Li , Shuai Liu , Thomas Donlon , Heidi Jo Newberg

We study the kinematics of the gaseous cosmic web at high redshift with Lyman alpha forest absorption in multiple QSO sightlines. Using a simple analytic model and a cosmological hydrodynamic simulation we constrain the underlying…

Previous observations of quasar host halos at z=2 have uncovered large quantities of cool gas that exceed what is found around inactive galaxies of both lower and higher masses. To better understand the source of this excess cool gas, we…

Astrophysics of Galaxies · Physics 2015-08-06 Sean D. Johnson , Hsiao-Wen Chen , John S. Mulchaey

We report the detection of OVI 1031,1037 and NV 1238,1242 absorption in a system of "mini-broad" absorption lines (mini-BALs) previously reported to have variable CIV 1548,1550 in the quasar PG0935+417. The formation of these lines in an…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Paola Rodríguez Hidalgo , Fred Hamann , Patrick Hall

HIRES/Keck spectra of Mg II (2796) absorption arising in the "halos" of 15 identified 0.4 < z < 0.9 galaxies are presented. Comparison of the galaxy and absorbing gas properties reveal that the spatial distribution of galactic/halo gas does…

Astrophysics · Physics 2007-05-23 Christopher W. Churchill

We present a detailed analysis of a large-scale galactic outflow in the CGM of a massive (M_h ~ 10^12.5 Msun), star-forming (6.9 Msun/yr), sub-L* (0.5 L_B*) galaxy at z=0.39853 that exhibits a wealth of metal-line absorption in the spectra…

In hierarchical clustering, galaxy clusters accrete mass through the aggregation of smaller systems. Thus, the velocity field of the infall regions of clusters contains significant random motion superimposed on radial infall. Because the…

Astrophysics · Physics 2009-12-15 Antonaldo Diaferio , Margaret J. Geller

This chapter presents a review of the current state of knowledge on the cool (T ~ 1e4 K) halo gas content around massive galaxies at z ~ 0.2-2. Over the last decade, significant progress has been made in characterizing the cool…

Astrophysics of Galaxies · Physics 2017-05-31 Hsiao-Wen Chen

We use cosmological SPH simulations to study the kinematic signatures of cool gas accretion onto a pair of well-resolved galaxy halos. Cold-flow streams and gas-rich mergers produce a circum-galactic component of cool gas that generally…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-30 Kyle R. Stewart , Tobias Kaufmann , James S. Bullock , Elizabeth J. Barton , Ariyeh H. Maller , Jürg Diemand , James Wadsley

We report ultraviolet spectra of Galactic high-velocity clouds (HVCs) in Complex C, taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), together with new 21-cm spectra from the Green Bank Telescope. The wide…

Astrophysics of Galaxies · Physics 2015-05-28 Michael Shull , Matthew Stevans , Charles Danforth , Steven Penton , Felix J. Lockman , Nahum Arav

The Owens Valley Radio Observatory (OVRO) millimeter array was used to make observations of the CS(2-1) line (at 97.981 GHz) arising from the G0.07+0.04 region of the ``-30 km/s'' molecular cloud near the Galactic center with a spatial…

Astrophysics · Physics 2009-11-07 Cornelia C. Lang , W. M. Goss , Mark Morris

High velocity (HV) outflows are an important but poorly understood aspect of quasar/SMBH evolution. Outflows during the luminous accretion phase might play a critical role in "unveiling" young dusty AGN and regulating star formation in the…

Astrophysics · Physics 2007-05-23 Paola Rodriguez Hidalgo , Fred Hamann , Daniel Nestor , Joseph Shields
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