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Short hard bursts. S. R. Kulkarni. References. This is a tutorial Primary reference: E. Berger (2013) Annual Review GW perspective: Kalsiwal & Nissanke (2013) . Properties. Defined primary by duration (T<2 s ) and further refined by hardness ratio
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Short hard bursts S. R. Kulkarni
References • This is a tutorial • Primary reference: E. Berger (2013) Annual Review • GW perspective: Kalsiwal & Nissanke (2013)
Properties • Defined primary by duration (T<2 s) and further refined by hardness ratio • In the BATSE sample the rate of short hard bursts (SHBs) is one quarter that of the total population (the remaining are Long Soft bursts). • Less fluence relative to long duration GRBs
Host Galaxies • Found in all types of environments • Clusters of galaxies • Elliptical galaxies • Field star forming galaxies • Interesting Clue: Association with ULRGs • GRB 100206A (dusty ULIRG, z=0.407) • GRB 120804A (dusty ULIRG, z=1.3) • But only 1% of mass is in ULIRGs
Comparing to other samples • Long duration GRBs are primarily found in low mass star-forming galaxies • SHBs appear to trace the field population of star forming galaxies • Just like SN of type Ia, SHBs arise infield galaxies of both old population and young star forming field galaxies • However the SN rate is higher in star-forming galaxies