The redshift distribution of SWIFT Gamma-Ray Bursts: evidence for evolution

Abstract

We predict the redshift distribution of long Gamma-Ray Bursts (GRBs) with Monte Carlo simulations. Our improved analysis constrains free parameters with three kinds of observation: (i) the log(N)-log(P) diagram of BATSE bursts; (ii) the peak energy distribution of bright BATSE bursts; (iii) the HETE2 fraction of X-ray rich GRBs and X-ray flashes. The statistical analysis of the Monte Carlo simulation results allow us to carefully study the impact of the uncertainties in the GRB intrinsic properties on the redshift distribution. The comparison with SWIFT data then leads to the following conclusions. The Amati relation should be intrinsic, if observationally confirmed by SWIFT. The progenitor and/or the GRB properties have to evolve to reproduce the high mean redshift of SWIFT bursts. Our results favor an evolution of the efficiency of GRB production by massive stars, that would be ~6-7 times higher at z~7 than at z~2. We finally predict around 10 GRBs detected by SWIFT at redshift z>6 for a three year mission. These may be sufficient to open a new observational window over the high redshift Universe.

10 pages, 14 figures. To appear in MNRAS

References in corpus (1)

• The redshift distribution of gamma-ray bursts revisited

Cited by in corpus (22)

• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion
• Star Formation History up to z = 7.4: Implications for Gamma-Ray Bursts and the Cosmic Metallicity Evolution
• Low-Luminosity Gamma-Ray Bursts as a Distinct GRB Population:A Firmer Case from Multiple Criteria Constraints
• The Gamma Ray Burst Luminosity Function in the Light of the Swift 2-year Data
• Do long-duration GRBs follow star formation?
• Intrinsic properties of a complete sample of HETE-2 gamma-ray bursts. A measure of the GRB rate in the Local Universe
• Enhanced Cosmological GRB Rates and Implications for Cosmogenic Neutrinos
• Probing the Neutral Fraction of the IGM with GRBs during the Epoch of Reionization
• Using Spatial Distributions to Constrain Progenitors of Supernovae and Gamma Ray Bursts
• Selection effects shaping the Gamma Ray Burst redshift distributions
• Testing Reionization with Gamma Ray Burst Absorption Spectra
• The host of GRB 060206: kinematics of a distant galaxy
• The low-luminosity tail of the GRB distribution: the case of GRB 980425
• Open issues with the gamma-ray burst redshift distribution
• "Orphan" afterglows in the Universal Structured Jet Model for gamma-ray bursts
• An Observational Limit on the Earliest GRBs
• Long Gamma-Ray Bursts and Their Host Galaxies at High Redshift
• On the detection of very high redshift Gamma Ray Bursts with Swift
• Robust photometric redshift determinations of gamma-ray burst afterglows at z > 2
• Near real-time selection of high redshift GRBs with Swift
• Probing the low-luminosity GRB population with new generation satellite detectors