Swift XRT follow-up observation of LXT 221107A


Following the new X-ray transient LXT 221107A detected by LEIA on November 7 2022 (ATel #15748), we performed a Swift target of opportunity observation. The XRT onboard Swift began the observation at 15:10:49 UT on November 9, 2022, with an exposure time of 1.49 ks in Photon Counting mode. The XRT ground-calculated position is RA (J2000) = 06:04:14.7, Dec (J2000) = 12:45:48.2, with an uncertainty of 3.5 arcsec (radius, 90% C.L. statistical and systematic), which is most likely associated with a rotating variable star (HD 251108) with an angular separation of only 3 arcsec. 

The XRT spectrum can be well fitted by an absorbed plasma model (thabs*mekal) with a temperature of 5.4 (+0.6/-0.7) keV. The corresponding flux in 0.5 - 4.0 keV is 1.05 (+/-0.02) x 10-10 erg cm-2 s-1, which seems to show a tendency of decline compared with the previous LEIA observations. The source is bright with a peak 0.5 - 4.0 keV flux of 5.0 (+/-1.3) x 10-10 erg cm-2 s-1, and it has been in a high state for at least three days, which is much longer than normal stellar flares. More follow-up observations are encouraged to identify this peculiar transient. 

We thank the Neil Gehrels Swift Observatory team for making the X-ray observation possible. 

The preliminary results have been posted at Astronomer's Telegram as ATel 15754. Click here for more EP/LEIA Astronomer's Telegrams.