English
Related papers

Related papers: A cold component and the complex velocity structur…

200 papers

We report results from our mini-survey for molecular hydrogen in eight high redshift damped Lyman-alpha (DLA) systems using the ESO Ultra-violet and Visible Spectrograph on the VLT. In addition, we investigate two systems using ESO public…

Astrophysics · Physics 2007-05-23 Patrick Petitjean , R. Srianand , Cédric Ledoux

We have obtained a moderate resolution spectrum of the quasar PKS 0528-250 with the Red Channel Spectrograph on the Multiple Mirror Telescope (MMT) in order to study a damped Lyman alpha absorption line system at z = 2.8115. We obtain a new…

Astrophysics · Physics 2016-08-30 Jian Ge , Jill Bechtold , Constance Walker , John , H. Black

We analyse high-resolution VLT+UVES spectra of the low-ionization intrinsic absorber observed in the BAL QSO SDSS J001130.56+005550.7. Two narrow absorption systems at velocities -600 km/s and -22000 km/s are detected. The low-velocity…

Astrophysics · Physics 2009-11-10 D. Hutsemekers , P. B. Hall , J. Brinkmann

We present a detailed analysis of chemical abundances in a sub-damped Lyman alpha absorber at z=1.839 towards the quasar B1101-26, based on a very-high-resolution (R ~ 75,000) and high-signal-to-noise (S/N >100) spectrum observed with the…

Astrophysics of Galaxies · Physics 2014-12-10 Anne Fox , Philipp Richter , Cora Fechner

We present high resolution echelle spectra of 7 proximate damped Lyman alpha (PDLA) systems whose relative velocity separation from the background quasar is Delta V < 3000 km/s. Combining our sample with a further 9 PDLAs from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Sara L. Ellison , J. Xavier Prochaska , Joseph Hennawi , Sebastian Lopez , Chris R. Benn , Chris G. Usher , Arthur M. Wolfe , David R. Russell

We used HST/STIS to obtain the spectrum of molecular hydrogen associated with the damped Ly$\alpha$ system at $z_{\rm abs}=1.7765$ toward the quasar Q1331+170 at $z_{\rm em}=2.084$. Strong ${\rm H}_2$ absorption was detected, with a total…

Astrophysics · Physics 2009-11-13 Jun Cui , Jill Bechtold , Jian Ge , David M. Meyer

We study the physical properties of a homogeneous sample of 157 optically-thick absorption line systems at redshifts ~1.8-4.4, selected from a high-dispersion spectroscopic survey of Lyman limit systems (LLSs). By means of multiple…

Astrophysics of Galaxies · Physics 2015-12-09 Michele Fumagalli , John M. O'Meara , J. Xavier Prochaska

We present a study of dense molecular gas kinematics in seventeen nearby protostellar systems using single-dish and interferometric molecular line observations. The non-axisymmetric envelopes around a sample of Class 0/I protostars were…

Physical properties of Damped Lyman-alpha absorbers and their evolution are closely related to galaxy formation and evolution theories, and have important cosmological implications. H I 21 cm absorption study is one useful way of measuring…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-30 Nirupam Roy , Smita Mathur , Vishal Gajjar , Narendra Nath Patra

We report the detection of H_2, CI, CI*, CI** and Cl I lines in a near Solar-metallicity ([Zn/H]=-0.13) damped Lyman-alpha (DLA) system at z_abs=1.962 observed on the line of sight to the quasar Q 0551-366. The iron-peak elements, X=Fe, Cr…

Astrophysics · Physics 2009-11-07 C. Ledoux , R. Srianand , P. Petitjean

By analyzing the X-ray spectra of NGC 3516 from 2001 and 2006 obtained with the HETGS spectrometer on board the Chandra observatory, we find that the kinematic structure of the outflow can be well represented by four outflow components…

Astrophysics of Galaxies · Physics 2015-06-03 Tomer Holczer , Ehud Behar

We present high-resolution observations of interstellar CN, CH, CH^{+}, \ion{Ca}{1}, and \ion{Ca}{2} absorption lines toward the multiple star systems HD206267 and HD217035. Substantial variations in CN absorption are observed among three…

Astrophysics · Physics 2009-11-07 K. Pan , S. R. Federman , D. E. Welty

Neutral hydrogen traces gravitational potentials. In the nearby universe, 21cm emission-line surveys show that the bulk of the HI resides in well-formed, optically-luminous galaxies. At high redshift, 21cm line absorption against background…

Astrophysics · Physics 2007-05-23 F. H. Briggs

We have used the Westerbork Synthesis Radio Telescope to detect HI 21cm absorption at $z \sim 0.7645$ in the gravitational lens system towards PMN J0134-0931. The 21cm profile has two broad components, with peak optical depths of $0.047 \pm…

Astrophysics · Physics 2009-11-10 N. Kanekar , F. H. Briggs

Detailed analysis of the spectral lines from two low redshift damped Lyman alpha absorbers (DLA) confirms that they are a heterogeneous population. Both systems have low metal abundances of approximately 0.05 to 0.1 solar. The abundance…

Astrophysics · Physics 2007-05-23 A. de la Varga , D. Reimers , D. Tytler , T. Barlow , S. Burles

Radio recombination lines at a wavelength of 20 cm reveals the presence of an extended component of ionized gas of lower density in the Sgr A complex. This component extends well beyond the thermal `mini-spiral' SgrA-West, which seem to be…

Astrophysics · Physics 2007-05-23 K. R. Anantharamaiah , A. Pedlar , W. M. Goss

The bright radio structure of the LINER elliptical galaxy NGC1052 is dominated by bi-symmetric jets on parsec scales. Features move outward on both sides of the core at v_{app}~0.26c. We have established the occurrence of free-free…

[Abridged] With VLT/X-shooter, we obtain optical and NIR spectra of six Ly-alpha blobs at z~2.3. Using three measures --- the velocity offset between the Lya line and the non-resonant [OIII] or H-alpha line (Dv_Lya), the offset of stacked…

Astrophysics of Galaxies · Physics 2015-06-22 Yujin Yang , Ann Zabludoff , Knud Jahnke , Romeel Davé

We present a detailed analysis of a very unusual sub-damped Lyman alpha (sub-DLA) system at redshift z=2.304 towards the quasar Q0453-423, based on high signal-to-noise (S/N), high-resolution spectral data obtained with VLT/UVES. With a…

Astrophysics of Galaxies · Physics 2016-03-23 Anne Fox , Philipp Richter

Radio spectroscopy at 323 MHz using the Arecibo Telescope and the VLA has produced a tentative detection of the 21cm line of neutral hydrogen at Z_abs=3.38716+-0.00007 in absorption against the radio continuum of the QSO MG0201+113 (Z_em =…

Astrophysics · Physics 2009-10-30 F. H. Briggs , E. Brinks , A. M. Wolfe