SSM on AstroSat detects neutron star X-ray transient, Aql_X-1 in its outburst
ATel #10452; Ramadevi M. C. (ISAC), Ravishankar, B. T. (ISAC), Abhilash R. Sarwade (ISAC), Vaishali, S. (ISAC), Mohammed Hasan (ISAC), Vivek Kumar Agarwal (ISAC), Blessy Elizabeth Baby (ISAC), Dipankar Bhattacharya (IUCAA), Seetha S. (ISRO), Anil Agarwal (ISAC)
on 2 Jun 2017; 13:28 UT
Credential Certification: M. C. Ramadevi (firstname.lastname@example.org)
Subjects: X-ray, Binary, Neutron Star, Transient
We report on the X-ray outburst of the neutron star X-ray source Aql X-1 as observed by SSM onboard AstroSat. Flux reported by SSM on its first observation of the source during this outburst on 01 June 2017 at 08:55 UT is about 820 milliCrab (2.24 +/- 0.02 photons/s-cm^2). SSM observed an increase in the flux in this source by about 50 milliCrab in its subsequent scans within a duration of 2 hours. Hardness ratio for the source (energy bands: 4-6 keV/ 2.5-4 keV) is estimated to be 0.8, which indicates the source to be in its softer state during its rising phase of its outburst.
Our observations are consistent with the reported onset of an optical/IR outburst (ATel#10441 & #10450) and enhanced hard X-ray activity (ATel 10450). Further multi-wavelength observations are encouraged.