Swift confirms outburst of transient in M15
ATel #15589; J. A. Kennea (PSU), A. Bahramian (Curtin), P. A. Evans (Leicester) and H. Negoro (Nihon U)
on 5 Sep 2022; 15:14 UT
Credential Certification: Jamie A. Kennea (kennea@astro.psu.edu)
Subjects: X-ray, Globular Cluster, Neutron Star
Negoro et al (ATel #15586) report the MAXI detection of an outbursting source in M15. On September 3rd, 2022 at 13:09UT, Swift performed a target-of-opportunity observation of the source, with a 1ks observation taken with XRT in Photon Counting (PC) mode. We find a bright source at the following location: RA/Dec(J2000) = 322.49242, 12.16698 which is equivalent to:
RA(J2000) = 21h 29m 58.18s,
Dec(J2000) = +12d 10m 01.1s,
with an error radius of 2.4 arc-seconds (90% confidence). We note that this position lies 2.3 arc-seconds from M15 X-2, consistent with its location, AC211 lies 2.6 arc-seconds from this position just outside of the error circle (positions from White and Angelini, 2001). Therefore, we cannot from these data alone identify which of these sources are in outburst.
The spectrum of is well fit by an absorbed power-law model with absorption N_H = 2.0 +/- 0.3 x 10^21 cm^-2 and photon index 1.89 +/- 0.1. The flux, corrected for pile-up and absorption is 1.54 +/- 0.08 x 10^-9 erg/s/cm^2 (0.3 - 10 keV , which is equivalent to a luminosity of ~2 x 10^37 erg/s (0.3 - 10 keV) assuming an 10.9 kpc distance to M15.
