Oxford Index Search Results

You are looking at 1-20 of 139 items for:

quasar absorption systems x clear all

Show only full text

Refine by type

Refine by product

 

quasar absorption systems

Overview page. Subjects: Astronomy and Astrophysics.

The name ‘quasar absorption system’ (sometimes called QSO absorption line system, or QSOALS for short) is a bit of a misnomer, since these are clouds of gas that lie between ...

See overview in Oxford Index

quasar absorption systems

Andrew Liddle and Jon Loveday.

in The Oxford Companion to Cosmology

January 2008; p ublished online January 2008 .

Reference Entry. Subjects: Astronomy and Astrophysics. 116 words.

The name ‘quasar absorption system’ (sometimes called QSO absorption line system, or QSOALS for short) is a bit of a

Go to Oxford Reference »  home page

quasar absorption systems

Overview page. Subjects: Astronomy and Astrophysics.

The name ‘quasar absorption system’ (sometimes called QSO absorption line system, or QSOALS for short) is a bit of a misnomer, since these are clouds of gas that lie between ...

See overview in Oxford Index

Circumgalactic medium of quasars: C iv absorption systems

M. Landoni, R. Falomo, A. Treves, R. Scarpa and E. P. Farina.

in Monthly Notices of the Royal Astronomical Society

P ublished online January 2016 .

Journal Article. Subjects: Astronomy and Astrophysics. 2949 words.

We investigate the properties of circumgalactic gas in the halo of quasar (QSO) host galaxies from C iv absorption-line systems. We use the optical spectroscopy of closely aligned pairs of...

Go to Oxford Journals »  full text

Nature and statistical properties of quasar associated absorption systems in the XQ-100 Legacy Survey

S. Perrotta, V. D'Odorico, J. X. Prochaska, S. Cristiani, G. Cupani, S. Ellison, S. López, G. D. Becker, T. A. M. Berg, L. Christensen, K. D. Denney, F. Hamann, I. Pâris, M. Vestergaard and G. Worseck.

in Monthly Notices of the Royal Astronomical Society

P ublished online July 2016 .

Journal Article. Subjects: Astronomy and Astrophysics. 14114 words.

We statistically study the physical properties of a sample of narrow absorption line (NAL) systems looking for empirical evidences to distinguish between intrinsic and intervening NALs...

Go to Oxford Journals »  full text

The host galaxies of strong Ca ii quasar absorption systems at z < 0.5

Berkeley J. Zych, Michael T. Murphy, Max Pettini, Paul C. Hewett, Emma V. Ryan-Weber and Sara L. Ellison.

in Monthly Notices of the Royal Astronomical Society

August 2007; p ublished online July 2007 .

Journal Article. Subjects: Astronomy and Astrophysics. 11275 words.

We present new imaging and spectroscopic observations of the fields of five quasars with very strong intervening Ca ii absorption systems at redshifts z abs < 0.5 selected from...

Go to Oxford Journals »  full text   » abstract

Quasars as the formation sites of high-redshift ellipticals: a signature in the ‘associated’ absorption-line systems?

A. Franceschini and R. Gratton.

in Monthly Notices of the Royal Astronomical Society

March 1997; p ublished online March 1997 .

Journal Article. Subjects: Astronomy and Astrophysics. 0 words.

Published data on the average metallicities and abundance ratios for absorption-line systems in high-redshift quasars suggest that a dichotomy may exist between the chemical composition of...

Go to Oxford Journals »  full text   » abstract

A ground-based imaging study of galaxies causing damped Lyman α (DLA), sub-DLA and Lyman limit system absorption in quasar spectra*

Sandhya M. Rao, Michèle Belfort-Mihalyi, David A. Turnshek, Eric M. Monier, Daniel B. Nestor and Anna Quider.

in Monthly Notices of the Royal Astronomical Society

September 2011; p ublished online September 2011 .

Journal Article. Subjects: Astronomy and Astrophysics. 18516 words.

We present results from a search for galaxies that give rise to damped Lyman α (DLA), sub-DLA and Lyman limit system (LLS) absorption at redshifts 0.1 ≲z≲ 1 in the spectra of background...

Go to Oxford Journals »  full text   » abstract

A robust deuterium abundance; re-measurement of the z = 3.256 absorption system towards the quasar PKS 1937−101

S. Riemer-Sørensen, J. K. Webb, N. Crighton, V. Dumont, K. Ali, S. Kotuš, M. Bainbridge, M. T. Murphy and R. Carswell.

in Monthly Notices of the Royal Astronomical Society

P ublished online January 2015 .

Journal Article. Subjects: Astronomy and Astrophysics. 6300 words.

The primordial deuterium abundance is an important tracer of the fundamental physics taking place during big bang nucleosynthesis. It can be determined from absorption features along the...

Go to Oxford Journals »  full text   » abstract

A precise deuterium abundance: remeasurement of the z = 3.572 absorption system towards the quasar PKS1937–101

S. Riemer-Sørensen, S. Kotuš, J. K. Webb, K. Ali, V. Dumont, M. T. Murphy and R. F. Carswell.

in Monthly Notices of the Royal Astronomical Society

P ublished online March 2017 .

Journal Article. Subjects: Astronomy and Astrophysics. 7146 words.

Abstract

The primordial deuterium abundance probes fundamental physics during the big bang nucleosynthesis and can be used to infer cosmological parameters....

Go to Oxford Journals »  full text

damped Lyman alpha systems

Overview page. Subjects: Astronomy and Astrophysics.

Damped Lyman alpha systems are dense clouds of neutral hydrogen gas that absorb all Lyman alpha (Lyα) photons incident upon them. They are thus an extreme form of quasar absorption system.

null...

See overview in Oxford Index

Narrow absorption line variability in repeat quasar observations from the Sloan Digital Sky Survey

Troy L. Hacker, Robert J. Brunner, Britt F. Lundgren and Donald G. York.

in Monthly Notices of the Royal Astronomical Society

September 2013; p ublished online July 2013 .

Journal Article. Subjects: Astronomy and Astrophysics. 16796 words.

We present the results from a time domain study of absorption lines detected in quasar spectra with repeat observations from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7)....

Go to Oxford Journals »  full text   » abstract

Narrow absorption lines with two observations from the Sloan Digital Sky Survey

Zhi-Fu Chen, Qiu-Sheng Gu, Yan-Mei Chen and Yue Cao.

in Monthly Notices of the Royal Astronomical Society

P ublished online May 2015 .

Journal Article. Subjects: Astronomy and Astrophysics. 7964 words.

We assemble 3524 quasars from the Sloan Digital Sky Survey (SDSS) with repeated observations to search for variations of the narrow [math] and [math] absorption doublets in spectral regions...

Go to Oxford Journals »  full text   » abstract

Directly imaging damped Lyα galaxies at z > 2 – II. Imaging and spectroscopic observations of 32 quasar fields

Michele Fumagalli, John M. O'Meara, J. Xavier Prochaska, Nissim Kanekar and Arthur M. Wolfe.

in Monthly Notices of the Royal Astronomical Society

P ublished online August 2014 .

Journal Article. Subjects: Astronomy and Astrophysics. 8538 words.

Damped Lyα absorbers (DLAs) are a well-studied class of absorption line systems, and yet the properties of their host galaxies remain largely unknown. To investigate the origin of these...

Go to Oxford Journals »  full text   » abstract

Catalog of SDSS Quasar Absorption Redshifts Measured from Mg II Absorption Lines. I. For Sources with z em ≤ 0.8

Yi-Ping Qin, Zhi-Fu Chen, Lian-Zhong LÜ, Wei-Rong Huang, Mu-Sheng Li, Guo-Qiang Li, Mei-Ping Wang, Yu-Qing Zhong, Sai-Qin Wen, Rong-Hua Liao and Feng Ye.

in Publications of the Astronomical Society of Japan

February 2013; p ublished online February 2013 .

Journal Article. Subjects: Galaxies; Astrometry and Celestial Mechanics. 5948 words.

We are going to analyze the whole Sloan Digital Sky Survey (SDSS) quasar spectra by visually identifying Mg II absorption line systems one by one. In this paper, we limit our analysis to...

Go to Oxford Journals »  full text

The large area KX quasar catalogue - I. Analysis of the photometric redshift selection and the complete quasar catalogue†‡

Natasha Maddox, Paul C. Hewett, Céline Péroux, Daniel B. Nestor and Lutz Wisotzki.

in Monthly Notices of the Royal Astronomical Society

August 2012; p ublished online August 2012 .

Journal Article. Subjects: Astronomy and Astrophysics. 14936 words.

ABSTRACT

The results of a large area, ∼600 deg2, K-band flux-limited spectroscopic survey for luminous quasars are presented. The survey utilizes the UKIRT...

Go to Oxford Journals »  full text   » abstract

Molecular hydrogen absorption systems in Sloan Digital Sky Survey

S. A. Balashev, V. V. Klimenko, A. V. Ivanchik, D. A. Varshalovich, P. Petitjean and P. Noterdaeme.

in Monthly Notices of the Royal Astronomical Society

P ublished online March 2014 .

Journal Article. Subjects: Astronomy and Astrophysics. 9832 words.

We present a systematic search for molecular hydrogen absorption systems at high redshift in quasar spectra from the Sloan Digital Sky Survey (SDSS)-II Data Release 7 and SDSS-III Data...

Go to Oxford Journals »  full text   » abstract

A ghostly damped Ly α system revealed by metal absorption lines

H. Fathivavsari, P. Petitjean, S. Zou, P. Noterdaeme, C. Ledoux, T. Krühler and R. Srianand.

in Monthly Notices of the Royal Astronomical Society: Letters

P ublished online November 2016 .

Journal Article. Subjects: Astronomy and Astrophysics. 3974 words.

Abstract

We report the discovery of the first ‘ghostly’ damped Ly α absorption system (DLA), which is identified by the presence of absorption from strong...

Go to Oxford Journals »  full text

Narrow associated quasi-stellar object absorbers: clustering, outflows and the line-of-sight proximity effect

Vivienne Wild, Guinevere Kauffmann, Simon White, Donald York, Matthew Lehnert, Timothy Heckman, Patrick B. Hall, Pushpa Khare, Britt Lundgren, Donald P. Schneider and Daniel Vanden Berk.

in Monthly Notices of the Royal Astronomical Society

July 2008; p ublished online July 2008 .

Journal Article. Subjects: Astronomy and Astrophysics. 12383 words.

Using data from the Sloan Digital Sky Survey data release 3 (SDSS DR3), we investigate how narrow (<700 km s−1) C iv and Mg ii quasar absorption-line systems are distributed around quasars....

Go to Oxford Journals »  full text   » abstract

The quasar-frame velocity distribution of narrow C iv absorbers

D. Nestor, F. Hamann and P. Rodriguez Hidalgo.

in Monthly Notices of the Royal Astronomical Society

June 2008; p ublished online April 2008 .

Journal Article. Subjects: Astronomy and Astrophysics. 8668 words.

We report on a survey for narrow (full widths at half-minimum <600 km s−1) C iv absorption lines in a sample of bright quasars at redshifts 1.8 ≤z < 2.25 in the Sloan Digital Sky Survey....

Go to Oxford Journals »  full text   » abstract

Dust obscuration studies along quasar sight-lines using simulated galaxies

D. K. Churches, A. H. Nelson and M. G. Edmunds.

in Monthly Notices of the Royal Astronomical Society

February 2004; p ublished online February 2004 .

Journal Article. Subjects: Astronomy and Astrophysics. 4639 words.

Abstract

We use the results of a set of three-dimensional SPH-treecode simulations which model the formation and early evolution of disc galaxies, including...

Go to Oxford Journals »  full text   » abstract