On the origin of short GRBs with extended emission and long GRBs without associated SN

Maurice H.P.M. Van Putten*, Gyeong Min Lee, Massimo Della Valle, Lorenzo Amati, Amir Levinson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

The Burst and Transient Source Experiment classifies cosmological gamma-ray bursts (GRBs) into short (less than 2 s) and long (over 2 s) events, commonly attributed to mergers of compact objects and, respectively, peculiar core-collapse supernovae. This standard classification has recently been challenged by the Swift discovery of short GRBs showing extended emission (SGRBEE) and nearby long GRBs without an accompanying supernovae (LGRBN). Both show an initial hard pulse, characteristic of SGRBs, followed by a long duration soft tail. We here consider the spectral peak energy (Ep, i)-radiated energy (Eiso) correlation and the redshift distributions to probe the astronomical and physical origin of these different classes of GRBs. We consider Swift events of 15 SGRBs, 7 SGRBEEs, 3 LGRBNs and 230 LGRBs detected by Swift. The spectral-energy properties of the initial pulse of both SGRBEE and LGRBNs are found to coincide with those of SGRBs. A Monte Carlo simulation shows that the redshift distributions of SGRBs, SGRBEE and LGRBNs fall outside the distribution of LGRBs at 4.75σ, 4.67σ and 4.31σ, respectively. A distinct origin of SGRBEEs with respect to LGRBs is also supported by the elliptical host galaxies of the SGRBEE events 050509B and 050724. This combined evidence supports the hypothesis that SGRBEE and LGRBNs originate in mergers as SGRBs. Moreover, long/soft tail of SGRB and LGRBNs satisfy the same Ep,i-Eiso Amati correlation holding for normal LGRBs. This fact points to rapidly rotating black holes as a common long-lived inner engine produced by different astronomical progenitors (mergers and supernovae).

Original languageEnglish
Pages (from-to)L58-L62
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume444
Issue number1
DOIs
StatePublished - 11 Oct 2014

Keywords

  • Gamma-ray burst: general
  • Stars: black holes
  • Stars: neutron

Fingerprint

Dive into the research topics of 'On the origin of short GRBs with extended emission and long GRBs without associated SN'. Together they form a unique fingerprint.

Cite this