Average power density spectrum of long GRBs detected with BeppoSAX/GRBM and with Fermi/GBM
Abstract
From past experiments the average power density spectrum (PDS) of gamma-ray bursts (GRBs) with unknown redshift was found to be modelled from 0.01 to 1 Hz with a power law, f-α, with α broadly consistent with 5/3. Recent analysis of the Swift/Burst Alert Telescope (BAT) catalogue showed analogous results in the 15-150 keV band. We carried out the same analysis on the bright GRBs detected by BeppoSAX/Gamma-ray Burst Monitor (GRBM) and Fermi/Gamma-ray Burst Monitor (GBM). The BeppoSAX/GRBM data, in the energy range 40-700 keV and with 7.8 and 0.5 ms time resolutions, allowed us to explore for the first time the average PDS at very high frequencies (up to 1 kHz) and reveal a break around 1-2 Hz, previously found in Compton Gamma Ray Observatory/Burst and Transient Source Experiment data. The Fermi/GBM data, in the energy band 8-1000 keV, allowed us to explore for the first time the average PDS within a broad energy range. Our results confirm and extend the energy dependence of the PDS slope, according to which harder photons have shallower PDS.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2013
- DOI:
- 10.1093/mnras/stt445
- arXiv:
- arXiv:1303.2584
- Bibcode:
- 2013MNRAS.431.3608D
- Keywords:
-
- accretion;
- accretion discs;
- turbulence;
- time;
- gamma-ray burst:general;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 13 pages, 9 figures, accepted to MNRAS