Fermi/GBM detection of the Be/XRB GRO J2058+42
ATel #12614; C. Malacaria (NASA-MSFC/USRA), P. Jenke (UAH-SPA/CSPAR), C. A. Wilson-Hodge (NASA/MSFC),O. J. Roberts (USRA/MSFC)
on 28 Mar 2019; 21:58 UT
Credential Certification: Christian Malacaria (christian.malacaria@nasa.gov)
We report on recent observations with Fermi/GBM of the transient Be/X-ray binary system GRO J2058+42.
Swift/BAT reported renewed activity from this source starting on 2019 March 22 (GCN #23985) and then on March 27 (GCN #24021). GBM also detected pulsations from the source starting on March 14 (MJD 58556) and then from March 17 (MJD 58559).
The source was previously undetected in GBM and is now undergoing a bright X-ray outburst. The current X-ray luminosity is Lx ~ 3x10^37 ergs/s (2-100 keV), estimated from the Swift/BAT lightcurve for a GAIA distance of 8.0 kpc. This is approaching the peak luminosity of Lx ~ 9.4x10^37 ergs/s (2-100 keV) from the 1995 giant outburst observed by BATSE (Wilson et al. 1998). BATSE initially detected pulsations at 5.04903(9) mHz on Sep 16, 1995. Pulsations are initially (MJD 58556.5266) detected by GBM at 5.111(1) mHz and spin-up is observed at an average rate of 1.396(6)x10^-11 Hz/s between MJD 58559.529 and 58569.534 (given values are not binary modulated).
The GBM pulse history of this source can be found at: http://gammaray.nsstc.nasa.gov/gbm/science/pulsars/lightcurves/groj2058.html
The Fermi/GBM Pulsar Project
