4U 1630-47 flux dropping, but still in the soft state
ATel #12083; Emrah Kalemci (Sabanci University)
on 7 Oct 2018; 18:50 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Emrah Kalemci (ekalemci@sabanciuniv.edu)
Subjects: X-ray, Black Hole, Transient
Black hole X-ray transient 4U1630-47 is in outburst since June 6, 2018 (MJD 58275) according to MAXI monitoring. The count rate dropped sharply after September 26, 2018 (MJD 58387), dropping to 0.2 photons s-1 cm-2 from 0.9 photons s-1 cm-2 in 8 days. After this sharp drop we triggered a target of opportunity observation with the Neil Gehrels Swift Observatory. The observation taken on October 06, 2018 shows a soft spectrum that can be fitted with a diskbb. The disk temperature is 1.06±0.02 keV, the NH is 1.22E23 and 1-10 keV flux is 2.2 10-9 ergs cm-2 s-1.
The source will be monitored further for possible signs of state change.
