Peak energy-isotropic energy relation in the off-axis gamma-ray burst model

Using a simple uniform jet model of prompt emissions of gamma-ray bursts (GRBs), we reproduce the observed peak energy-isotropic energy relation. A Monte Carlo simulation shows that the low isotropic energy part of the relation is dominated by events viewed from off-axis directions, and the number of the off-axis events is about one-third of the on-axis emissions. We also compute the observed event rates of the GRBs, the X-ray-rich GRBs, and the X-ray flashes detected by High Energy Transient Explorer 2, and we find that they are similar.

[1]  W. Priedhorsky,et al.  Fast X-Ray Transients and Their Connection to Gamma-Ray Bursts , 2003, astro-ph/0304347.

[2]  Xinyu Dai,et al.  Quasi-universal Gaussian Jets: A Unified Picture for Gamma-Ray Bursts and X-Ray Flashes , 2004 .

[3]  Z. Dai,et al.  Failed gamma-ray bursts and orphan afterglows , 2001, astro-ph/0112469.

[4]  W. S. Paciesas,et al.  The BATSE Gamma-Ray Burst Spectral Catalog. I. High Time Resolution Spectroscopy of Bright Bursts Using High Energy Resolution Data , 2000 .

[5]  S. R. Kulkarni,et al.  BEAMING IN GAMMA-RAY BURSTS: EVIDENCE FOR A STANDARD ENERGY RESERVOIR , 2001 .

[6]  S. G. Djorgovski,et al.  The First Two Host Galaxies of X-Ray Flashes: XRF 011030 and XRF 020427 , 2003, astro-ph/0303514.

[7]  T. Totani,et al.  Orphan Afterglows of Collimated Gamma-Ray Bursts: Rate Predictions and Prospects for Detection , 2002, astro-ph/0204258.

[8]  Ryo Yamazaki,et al.  X-Ray Flashes from Off-Axis Gamma-Ray Bursts , 2002 .

[9]  J. Atteia,et al.  A simple empirical redshift indicator for gamma-ray bursts , 2003, astro-ph/0304327.

[10]  Gregory Y. Prigozhin,et al.  High Energy Transient Explorer 2 Observations of the Extremely Soft X-Ray Flash XRF 020903 , 2004 .

[11]  Jay D. Salmonson,et al.  Discovery of a Tight Correlation between Pulse Lag/Luminosity and Jet-Break Times: A Connection between Gamma-Ray Bursts and Afterglow Properties , 2001, astro-ph/0112298.

[12]  Takashi S. Nakamura,et al.  Peak Luminosity-Spectral Lag Relation Caused by the Viewing Angle of the Collimated Gamma-Ray Bursts , 2001, astro-ph/0105321.

[13]  J. G. Jernigan,et al.  Spectral analysis of 35 GRBs/XRFs observed with HETE-2/FREGATE , 2002 .

[14]  Bing Zhang,et al.  An Analysis of Gamma-Ray Burst Spectral Break Models , 2002 .

[15]  Cristiano Porciani,et al.  On the Association of Gamma-Ray Bursts with Massive Stars: Implications for Number Counts and Lensing Statistics , 2001 .

[16]  J. Hjorth,et al.  Gamma-Ray Bursts in the Afterglow Era , 2001 .

[17]  Usra,et al.  X-ray flashes and X-ray rich Gamma Ray Bursts , 2001, astro-ph/0111246.

[18]  M. Feroci,et al.  Intrinsic spectra and energetics of BeppoSAX Gamma-Ray Bursts with known redshifts , 2002, astro-ph/0205230.

[19]  S. E. Woosley,et al.  The propagation and eruption of relativistic jets from the stellar progenitors of gamma-ray bursts , 2004 .

[20]  A. Panaitescu,et al.  Properties of Relativistic Jets in Gamma-Ray Burst Afterglows , 2001, astro-ph/0109124.

[21]  Ryo Yamazaki,et al.  Cosmological X-Ray Flashes in the Off-Axis Jet Model , 2003 .

[22]  P. Kumar,et al.  Off-Axis Afterglow Emission from Jetted Gamma-Ray Bursts , 2002 .

[23]  K. Ioka,et al.  Delayed Flashes from Counterjets of Gamma-Ray Bursts , 2002, astro-ph/0207606.

[24]  D. J. Helfand,et al.  The Einstein Observatory Detection of Faint X-Ray Flashes , 1996 .

[25]  D. Yonetoku,et al.  An off-axis jet model for GRB 980425 and low-energy gamma-ray bursts , 2003, astro-ph/0306615.

[26]  Enrico Ramirez-Ruiz,et al.  Beam models for gamma-ray bursts sources: outflow structure, kinematics and emission mechanisms , 2002 .

[27]  S. R. Kulkarni,et al.  Gamma-Ray Burst Energetics and the Gamma-Ray Burst Hubble Diagram: Promises and Limitations , 2003 .

[28]  D. Palmer,et al.  BATSE observations of gamma-ray burst spectra. I: Spectral diversity , 1993 .

[29]  F. Daigne,et al.  The physics of pulses in gamma‐ray bursts: emission processes, temporal profiles and time‐lags , 2003 .

[30]  H. C. Spruit,et al.  Efficient acceleration and radiation in Poynting flux powered GRB outflows , 2002, astro-ph/0202387.

[31]  J. Chiang,et al.  Fireball Loading and the Blast-Wave Model of Gamma-Ray Bursts , 1998, astro-ph/9804174.

[32]  E. Ramirez-Ruiz,et al.  X-Ray-rich Gamma-Ray Bursts, Photospheres, and Variability , 2002, astro-ph/0205144.

[33]  Possible Origin of Lognormal Distributions in Gamma-Ray Bursts , 2002, astro-ph/0202053.