X-ray Outburst of Aql X-1 indicated by the The Neil Gehrels Swift Observatory
ATel #15403; Devraj Pawar (R. J. College, Mumbai 400086, India)
on 30 May 2022; 12:01 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Devraj Pawar (devrajdp@gmail.com)
Subjects: Radio, Optical, Ultra-Violet, X-ray, Binary, Neutron Star, Transient
Referred to by ATel #: 16147
An optical brightening of Aql X-1 was reported by ATel #15401 on 27th May 2022. Following this we requested The Neil Gehrels Swift Observatory for monitoring observations of Aql X-1.
Quick look data analysis results following Evans et al. (2009, MNRAS, 397, 1177) indicate that the unabsorbed flux in the 0.3-10 keV band using the XRT shows an increase from 2.98(0.23,-0.19) X 10^-9 erg/cm2/s to 4.29(0.31,-0.26) X 10^-9 erg/cm2/s in ~20 hours. This rate of increase in the flux is consistent with the rapid increase characteristic of this source. A third observation on 30th May 2022 also shows an increase in the flux. A comparison with the light curve of its previous outbursts indicates that the count rate is indeed above quiescence level ( link to the light curve).
The optical brightening and increase of the X-ray flux indicates the beginning of a new outburst of Aql X-1. Multi-wavelength observations of this source are encouraged.
XRT observations of Aql X-1:
Date |
MJD |
Flux |
XRT c/s |
Photon Index |
Exposure |
|
|
(0.3-10keV) |
(0.3-10keV) |
|
(seconds) |
|
|
(10^-9 erg/s/cm2) |
|
|
|
2022/05/28 |
59727.19 |
2.98(+0.23, -0.19) |
35.69(0.68,-0.68) |
2.068(+0.100, -0.096) |
811 |
2022/05/29 |
59728.05 |
4.29(+0.31, -0.26) |
54.98(1.09,-1.09) |
1.956(+0.104, -0.099) |
890 |
2022/05/30 |
59729.24 |
5.89(+1.22, -0.79) |
78.24(3.97,-3.97) |
1.94(+0.25, -0.24) |
655 |
The above table updated with further approved XRT observations during this outburst will be updated here.
We thank the Neil Gehrels Swift Observatory team for quickly scheduling the observations. We acknowledge the use of public data from the Swift data archive.