LORENTZ-FACTOR-ISOTROPIC-LUMINOSITY/ENERGY CORRELATIONS OF GAMMA-RAY BURSTS AND THEIR INTERPRETATION

• Published in: The Astrophysical journal Vol. 751; no. 1; pp. 1 - 6
• Main Authors: JING LÜ, ZOU, Yuan-Chuan, LEI, Wei-Hua, BING ZHANG, QINGWEN WU, WANG, Ding-Xiong, LIANG, En-Wei, LÜ, Hou-Jun
• Format: Journal Article
• Language: English
• Published: Bristol IOP 20-05-2012
• Subjects: ANNIHILATION; Astronomy; ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Asymptotic properties; BARYONS; BLACK HOLES; Black holes (astronomy); CORRECTIONS; Correlation; CORRELATIONS; COSMIC GAMMA BURSTS; COSMIC NEUTRINOS; Disks; Earth, ocean, space; Engines; Exact sciences and technology; Gamma ray bursts; JETS; Lorentz factor; LORENTZ TRANSFORMATIONS; LUMINOSITY; MASS; RELATIVISTIC RANGE; STELLAR WINDS; gamma-ray burst: general; Correlation energy; Cosmic gamma sources; Black holes; Luminosity; Gamma ray burst; Baryons; relativistic processes; Stellar mass; black hole physics; Correlations; Neutrinos; Elementary particles; Cosmology; Jets; Massless particles; Corrections
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/751/1/49

The bulk Lorentz factor of the gamma-ray burst (GRB) ejecta ([Gamma] sub(0)) is a key parameter to understanding GRB physics. Liang et al. have discovered a correlation between [Gamma] sub(0) and isotropic gamma -ray energy: [Gamma] sub(0) [is proportional to] E super(0.25) gamma ,iso,52. By including more GRBs with updated data and more methods to derive [Gamma] sub(0), we confirm this correlation and obtain [Gamma] sub(0) [Asymptotically = to] 91E super(0.29) gamma ,iso,52. Evaluating the mean isotropic gamma -ray luminosities L gamma ,iso of the GRBs in the same sample, we discover an even tighter correlation [Gamma] sub(0) [Asymptotically = to] 249L super(0.30) gamma ,iso,52. We propose an interpretation to this later correlation. Invoking a neutrino-cooled hyperaccretion disk around a stellar mass black hole as the central engine of GRBs, we derive jet luminosity powered by neutrino annihilation and baryon loading from a neutrino-driven wind. Applying beaming correction, we finally derive [Gamma] sub(0) [is proportional to] L super(0.22) gamma ,iso, which is consistent with the data. This suggests that the central engine of long GRBs is likely a stellar mass black hole surrounded by a hyper-accreting disk.