Low Luminosity Gamma Ray Burst

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Low Luminosity Gamma Ray Bursts (llGRB for short) are astronomical gamma ray bursts with an unusually low luminosity of 10 46 to 10 49 erg / s and thus at least a hundred times weaker than other long GRBs. Furthermore, their brightness curve and the spectral development are atypical for gamma ray bursts, which is why they are probably generated by a different mechanism.

properties

The low luminosity gamma ray bursts observed so far show the following properties:

  • The duration T 90 , in which 90 percent of the emitted radiation is received, is more than 10 seconds and less than a few hours. It is therefore in the range of the long GRBs
  • The luminosity is in the range from 10 46 to 10 49 erg / s and thus at least two orders of magnitude below the normal gamma ray bursts. Accordingly, this subspecies of GRBs can only be observed in the local universe
  • In contrast to the light curves of normal gamma ray bursts, IIGRB shows a smooth curve with only one maximum
  • The spectrum of gamma rays is unusually soft (low energy gamma rays)
  • The llGRBs occur frequently, but not always, together with a supernova at the location of the explosion
  • All IIGRBs show an afterglow in the area of ​​radio radiation after a few days to weeks

Interpretations

Normal gamma ray bursts are interpreted in connection with stellar jets as strongly directed outflows of matter and electromagnetic radiation. The frequency of the llGRBs per volume is so great that they cannot be jets, as this would exceed the observed rate of stripped-envelope supernova at the location of the GRBs. Thus, the low luminosity gamma ray bursts do not arise according to the Kollapsar model, which is the leading hypothesis for long GRBs. A failed jet in combination with a supernova shock breakout is discussed as an alternative model . llGRBs could be a source of high energy cosmic rays in the range up to 10-20 electron volts .

Examples

  • GRB 980425
  • GRB 031203
  • GRB 060218
  • GRB 100316D

literature

  • Rodolfo Barniol Duran, Ehud Nakar, Tsvi Piran, Re'em Sari: The afterglow of a relativistic shock breakout and low luminosity GRBs . In: Astrophysics. Solar and Stellar Astrophysics . 2014, arxiv : 1407.4475v1 .
  • Tsvi Piran, Omer Bromberg, Ehud Nakar, Re'em Sari: The Long, the Short and the Weak - the origin of GRBs . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1206.0700v2 .
  • Bin-Bin Zhang, Yi-Zhong Fan, Rong-Feng Shen, Dong Xu, Fu-Wen Zhang, Da-Ming Wei, David N. Burrows, Bing Zhang, Neil Gehrels: GRB 120422A: A Low-luminosity Gamma-ray Burst Driven by Central Engine . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1206.0298v2 .
  • Ruo-Yu Liu, Xiang-Yu Wang, Zi-Gao Dai: Nearby low-luminosity GRBs as the sources of ultra-high energy cosmic rays revisited . In: Astrophysics. Solar and Stellar Astrophysics . 2011, arxiv : 1108.1551v1 .
  • Omer Bromberg, Ehud Nakar, Tsvi Piran: Are low luminosity GRBs generated by relativistic jets? In: Astrophysics. Solar and Stellar Astrophysics . 2011, arxiv : 1107.1346v1 .