Intervening Metal Systems in GRB and QSO sight-lines: The Mgii and Civ Question

Abstract

Prochter et al. 2006 recently found that the number density of strong intervening 0.5<z<2 MgII absorbers detected in gamma-ray burst (GRB) afterglow spectra is nearly 4 times larger than in QSO spectra. We have conducted a similar study using CIV absorbers. Our CIV sample, consisting of a total of 20 systems, is drawn from 3 high resolution and high to moderate S/N VLT/UVES spectra of 3 long-duration GRB afterglows, covering the redshift interval 1.6< z<3.1. The column density distribution and number density of this sample do not show any statistical difference with the same quantities measured in QSO spectra. We discuss several possibilities for the discrepancy between CIV and MgII absorbers and conclude that a higher dust extinction in the MgII QSO samples studied up to now would give the most straightforward solution. However, this effect is only important for the strong MgII absorbers. Regardless of the reasons for this discrepancy, this result confirms once more that GRBs can be used to detect a side of the universe that was unknown before, not necessarily connected with GRBs themselves, providing an alternative and fundamental investigative tool of the cosmic evolution of the universe.

arXiv comment21 pages, 4 figures, ApJ accepted, Revised after Referee Report

References in corpus (35)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Damped Lyman Alpha Systems at z<1.65: The Expanded SDSS HST Sample
• Signatures of Extragalactic Dust in pre-Swift GRB Afterglows
• The Enrichment History of the Intergalactic Medium: Measuring the CIV/HI Ratio in the Lyman Alpha Forest
• Average Extinction Curves and Relative Abundances for QSO Absorption Line Systems at 1 <= z_abs < 2
• Probing Cosmic Chemical Evolution with Gamma-Ray Bursts: GRB060206 at z=4.048
• GRBs as Cosmological Probes - Cosmic Chemical Evolution
• Heavy Element Abundances and Dust Depletions in the Host Galaxies of Three Gamma-Ray Bursts
• HI column densities of z > 2 Swift gamma-ray bursts
• The Gaseous Extent of Galaxies and the Origin of Lya Absorption Systems. V. Optical and Near-Infrared Photometry of Lya-absorbing Galaxies at z < 1
• Echelle Spectroscopy of a GRB Afterglow at z=3.969: A New Probe of the Interstellar and Intergalactic Media in the Young Universe
• Rapid-Response Mode VLT/UVES spectroscopy of GRB060418: Conclusive evidence for UV pumping from the time evolution of FeII and NiII excited- and metastable-level populations
• Dust Depletion and Extinction in a Gamma-Ray Burst Afterglow
• Spectroscopy of GRB 050505 at z=4.275: A logN(HI)=22.1 DLA Host Galaxy and the Nature of the Progenitor
• Selecting damped Lyman-alpha systems through CaII absorption. I: Dust depletions and reddening at z~1
• The Properties of Intergalactic C IV and Si IV Absorption, I: Optimal Analysis of an Extremely High S/N Quasar Sample
• On the Incidence of Strong MgII Absorbers Along GRB Sightlines
• The dust obscuration bias in Damped Lyman alpha systems
• Microlensing of $\gamma$-Ray Burst Afterglows
• The clustering of the luminosities of optical afterglows of long Gamma Ray Bursts
• The Interstellar Medium of GRB Host Galaxies I. Echelle Spectra of Swift GRB Afterglows
• Evidence for dust reddening in DLAs identified through CaII H&K absorption
• UVES/VLT high resolution spectroscopy of GRB 050730 afterglow: probing the features of the GRB environment
• The Number Density of 0.6 < z < 1.7 MgII Systems from CORALS: Observational Biases at Intermediate Redshift
• Three intervening galaxy absorbers towards GRB060418: faint and dusty?
• Strong MgII systems in quasar and gamma-ray burst spectra
• Strongly Variable z=1.48 FeII and MgII Absorption in the Spectra of z=4.05 GRB 060206
• The Properties of Intergalactic CIV Absorption II: Which Systems Are Associated With Galaxy Outflows?
• Disparate MgII Absorption Statistics towards Quasars and Gamma-Ray Bursts : A Possible Explanation
• MMT Survey for Intervening MgII Absorption
• Evidence for a magnitude-dependent bias in the Hamburg/ESO Survey for Damped Lyman-alpha Systems
• Microlensing induced absorption line variability
• Dust obscuration of DLA galaxies
• UVES - VLT High Resolution Spectroscopy of GRB Afterglows

Cited by in corpus (29)

• Low-Resolution Spectroscopy of Gamma-ray Burst Optical Afterglows: Biases in the Swift Sample and Characterization of the Absorbers
• The Afterglows of Swift-era Gamma-Ray Bursts. I. Comparing pre-Swift and Swift era Long/Soft (Type II) GRB Optical Afterglows
• The Host Galaxies of Swift Dark Gamma-Ray Bursts: Observational Constraints on Highly Obscured and Very High-Redshift GRBs
• Star Formation History up to z = 7.4: Implications for Gamma-Ray Bursts and the Cosmic Metallicity Evolution
• Dust and Metal Column Densities in Gamma-Ray Burst Host Galaxies
• GRB 100219A with X-shooter - abundances in a galaxy at z = 4.7
• High-Redshift Starbursting Dwarf Galaxies Revealed by GRB Afterglows
• X-ray absorption evolution in Gamma-Ray Bursts: intergalactic medium or evolutionary signature of their host galaxies?
• VLT/X-shooter spectroscopy of the GRB 120327A afterglow
• Statistics and characteristics of MgII absorbers along GRB lines of sight observed with VLT-UVES
• VLT/X-shooter spectroscopy of the GRB 090926A afterglow
• The host of GRB 060206: kinematics of a distant galaxy
• UVES/VLT high resolution absorption spectroscopy of the GRB080330 afterglow: a study of the GRB host galaxy and intervening absorbers
• Dusty MgII absorbers: population statistics, extinction curves and gamma-ray burst sightlines
• Casting light on the 'anomalous' statistics of Mg II absorbers toward Gamma-Ray Burst afterglows: the incidence of weak systems
• Incidence of MgII absorbers towards Blazars and the GRB/QSO puzzle
• Testing the Possible Intrinsic Origin of the Excess of Very Strong MgII Absorbers Along GRB Lines-of-Sight
• Dusty MgII Absorbers: Implications for the GRB/Quasar Incidence Discrepancy
• Solving the conundrum of intervening strong MgII absorbers towards GRBs and quasars
• Direct Observational Test Rules Out Small MgII Absorbers
• A gravitational lensing explanation for the excess of strong Mg-II absorbers in GRB afterglow spectra
• The Redshift Distribution of Intervening Weak MgII Quasar Absorbers and a Curious Dependence on Quasar Luminosity
• Constraints on the relative sizes of intervening Mg II-absorbing clouds and quasar emitting regions
• Non variability of intervening absorbers observed in the UVES spectra of the "naked-eye" GRB080319
• Incidence of Mg II absorption systems towards flat-spectrum radio quasars
• On the incidence of MgII absorbers along the blazar sightlines
• Signature of outflows in strong MgII absorbers in quasar sightlines
• Clustering of galaxies around GRB sight-lines
• GRBs as Probes of the IGM