Short versus long gamma-ray bursts: a comprehensive study of energetics and prompt gamma-ray correlations

Abstract

We present the results of a comprehensive study of the luminosity function, energetics, prompt gamma-ray correlations, and classification methodology of short-hard and long-soft GRBs (SGRBs & LGRBs), based on observational data in the largest catalog of GRBs available to this date: BATSE catalog of 2702 GRBs. We find that: 1. The least-biased classification method of GRBs into short and long, solely based on prompt-emission properties, appears to be the ratio of the observed spectral peak energy to the observed duration (R = E p /T 90 ) with the dividing line at R 50[keV s −1 ]. 2. Once data is carefully corrected for the effects of the detection threshold of gammaray instruments, the population distribution of SGRBs and LGRBs can be individually well described as multivariate log-normal distribution in the 4-dimensional space of the isotropic peak gamma-ray luminosity, total isotropic gamma-ray emission, the intrinsic spectral peak energy, and the intrinsic duration. 3. Relatively large fractions of SGRBs and LGRBs with moderate-to-low spectral peak energies have been missed by BATSE detectors. 4. Relatively strong and highly significant intrinsic hardnessbrightness and duration-brightness correlations likely exist in both populations of SGRBs and LGRBs, once data is corrected for selection effects. The strengths of these correlations are very similar in both populations, implying similar mechanisms at work in both GRB classes, leading to the emergence of these prompt gamma-ray correlations.

The Ep,i–Eiso correlation: type I gamma-ray bursts and the new classification method

“…Attempts of using the combination of E p , E iso , T 90,i parameters and Amati relation as classification discriminators were made in several papers (e.g. Lü et al 2010;Qin & Chen 2013;Zhang et al 2018b;Shahmoradi & Nemiroff 2015;Zou et al 2018;Pozanenko et al 2018). Below we briefly compare the several classification schemes.…”

“…In Shahmoradi & Nemiroff (2015) the classification parameter R = E p /T 90 was proposed as least affected parameter by the detection threshold of gamma-ray detectors. It was also suggested, that the two GRB types are most distinctively separated in the E p -T 90 plane.…”

“…Type I bursts were found to be outliers of the E p,i -E iso correlation for type II bursts, so the correlation could also be used for the classification of GRBs (e.g. Lü et al 2010;Zhang et al 2012;Qin & Chen 2013;Zhang et al 2018b;Shahmoradi & Nemiroff 2015;Zou et al 2018;Pozanenko et al 2018). More over, in Pozanenko et al (2019b) the Amati relation was used to estimate the E p,i value for the second LIGO/Virgo event S190425z connected with binary neutron star merger, which was observed in gamma-ray domain by SPI-ACS/INTEGRAL experiment.…”

Diffuse emission of high-energy neutrinos from gamma-ray burst fireballs

“…3.19). However, we know from observations that the low-energy component (i.e., for E γ < E γ,b ) is harder for sGRBs than for the long-duration GRBs (see the values for α γ in Table 1) and the peak energy is slightly higher [61][62][63].…”

Analysis of the observed and intrinsic durations of gamma-ray bursts with known redshift

“…Kouveliotou et al (1993) also found a bimodal structure in the log T 90 distribution of 222 events from CGRO/BATSE, based on which GRBs are commonly divided into short (T 90 < 2 s) and long (T 90 > 2 s) classes, where T 90 is the time interval from 5 % to 95 % of the accumulated fluence. While generally short GRBs are of merger origin (Nakar 2007) and long ones come from collapsars (Woosley and Bloom 2006), this classification is imperfect due to a large overlap in duration distributions of the two populations (Lü et al 2010;Bromberg et al 2011Bromberg et al , 2013Shahmoradi 2013;Shahmoradi and Nemiroff 2015;Tarnopolski 2015c). Horváth (1998) and Mukherjee et al (1998) independently discovered a third peak in the duration distribution in the BATSE 3B catalog, located between the short and long groups, and the statistical existence of this intermediate class was claimed to be supported (Horváth 2002) with the use of BATSE 4B data.…”