Swift/XRT follow-up observations of IGRJ12341-6143
ATel #15670; L. Sidoli (INAF-IASF Milano, Italy), V. Sguera (INAF-OAS Bologna, Italy) and P. Esposito (IUSS Pavia, Italy)
on 12 Oct 2022; 15:13 UT
Credential Certification: Lara Sidoli (sidoli@lambrate.inaf.it)
Subjects: X-ray, Binary, Neutron Star, Transient
Following the INTEGRAL/JEM-X detection of a new outburst from the candidate Supergiant Fast X-ray Transient IGR J12341-6143 (ATel #15643), we have asked for a Swift/XRT monitoring of its activity. Four XRT observations were performed from 2022-10-08 to 2022-10-12 (after about 5.6 days from the JEM-X detection), with a daily cadence and an average, nominal, exposure time of about 900 seconds per observation.
The analysis of the Swift quick-look data revealed no X-ray source at the transient position (ATel #14039), with a 3sigma upper limit of about 0.016 c/s (0.3-10 keV; XRT/PC) per each single observation. The source remains undetected also in the combined image of the four observations.
Using WebPIMMS with a power law model (photon index = 2) and an absorbing column density of 9E21 cm^-2, the upper limit translates into X-ray fluxes corrected for the absorption of 1.5E-12 erg/cm^2/s (0.3-10 keV) and 5.1E-13 erg/cm^2/s (3-10 keV). This latter value implies a dynamic range > 170 when compared with the flux reported in outburst about 5 days earlier (ATel #15643). Assuming a source distance of 6.9 kpc (ATel #14039), the Swift upper limit translates into an X-ray luminosity below 8.5E33 erg/s (0.3-10 keV), consistent with a Supergiant Fast X-ray Transient nature (Sguera et al. 2020, MNRAS 491, 4543).
We thank the Swift PI, Brad Cenko, for approving these ToO observations, and the Swift Team and Observatory Duty Scientists who made these observations possible.
