Burst Properties of the Most Recurring Transient Magnetar SGR J1935+2154
Abstract
We present timing and time-integrated spectral analysis of 127 bursts from SGR J1935+2154. These bursts were observed with the Gamma-ray Burst Monitor on the Fermi Gamma-ray Space Telescope and the Burst Alert Telescope on the Neil Gehrels Swift Observatory during the source's four active episodes from 2014 to 2016. This activation frequency makes SGR J1935+2154 the most burst prolific transient magnetar. We find the average duration of all the detected bursts to be much shorter than the typical, anticipated value. We fit the burst time-integrated spectra with two blackbody functions, a Comptonized model and three other simpler models. Bursts from SGR J1935+2154 exhibit similar spectral properties to other magnetars, with the exception of the power-law index from the Comptonized model, which correlates with burst fluence. We find that the durations and both blackbody temperatures of the bursts have significantly evolved across the four active episodes. We also find that the burst time history exhibits two trends, which are strongly correlated with the decay of the persistent emission in each outburst.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2020
- DOI:
- 10.3847/1538-4357/ab818f
- arXiv:
- arXiv:2003.10582
- Bibcode:
- 2020ApJ...893..156L
- Keywords:
-
- Magnetars;
- Soft gamma-ray repeaters;
- Neutron stars;
- Transient sources;
- Gamma-ray transient sources;
- X-ray transient sources;
- 992;
- 1471;
- 1108;
- 1851;
- 1853;
- 1852;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- A mistake has been corrected when calculating the burst isotropic energy from fluence. We updated the total burst energies in the rightmost column of Table 2 and the energy ratio between burst and persistent outburst for each episode in Section 4.2. All discussions and conclusions remain the same after these changes. An erratum has been accepted by ApJ. We are truly sorry for this mistake