Swift confirms outburst of SAX J1747.0-2853 (AKA MAXI J1746-287)
ATel #15347; J. A. Kennea (PSU), A. Bahramian (ICRAR), P. A. Evans, A. P. Beardmore (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), P. Romano (INAF-IASFPA), K. Yamaoka (Nagoya U.), M. Serino (RIKEN), H. Negoro (Nihon U.)
on 25 Apr 2022; 10:59 UT
Credential Certification: Jamie A. Kennea (kennea@astro.psu.edu)
Subjects: X-ray, Binary, Transient
Referred to by ATel #: 15368
Iwakiri et al (ATEL #15346) reported transient activity near the galactic center, tentatively naming the source MAXI J1746-287. This source lies close to the known source SAX J1747.0-2853 and 1E1743.1-2843, however MAXI could not resolve which source the outburst was from.
Therefore we requested a Swift TOO request to observe the MAXI error circle. The observation consisted of 3 pointings, with a total exposure of 1ks for all three, taken in PC mode, which began at 05:44UT on April 25, 2022. In these observations, we detect two X-ray sources, 1E1743.1-2843 and SAX J1747.0-2853, however, SAX J1747.0-2853 dominates the flux, being highly piled up in PC mode. We therefore conclude that MAXI J1746-287 is indeed SAX J1747.0-2853 in outburst. Analyzing the Swift data we find a position of RA/Dec(J2000) = 266.76035, -28.88333, equivalent to:
RA(J2000) = 17h 47m 02.48s
Dec(J2000) = -28d 52m 60.0s
with an error radius 2.6 arcseconds (90% confidence). The pile-up correct PC mode spectrum is well fit by an absorbed power-law model with photon index 2.8 (+0.6, -0.5) and absorption N_H = 1.8 (+0.4, -0.3) x 10^23 cm^-2. The observed flux was 4.1 (+0.5, -0.5) x 10^-9 erg cm^-2 s^-1 (0.3 - 10 keV).
We thank the Swift team for their prompt action to follow-up this TOO request.
This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.
