***Instant Email Notice***: Transients ------------------------------------------------------------------------------ The Astronomer's Telegram is free to read, free to publish, free to use.  Thanks to the support of our patrons, we can continue to keep it free. https://www.patreon.com/astronomerstel ------------------------------------------------------------------------------ The Astronomer's Telegram                   http://www.astronomerstelegram.org ============================================================================== ATEL #15754     ATEL #15754 Title: Swift XRT follow-up observation of the newly discovered X-ray transient LXT 221107A Author: D. Y. Li, Z. X. Ling, Y. Liu, C. Zhang, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, M. H. Huang, C. C. Jin, J. Q. Li, H. Y. Liu, M. J. Liu, H. Sun, H. W. Pan, W. X. Wang, Y. L. Wang, Q. Y. Wu, X. P. Xu, Y. F. Xu, H. N. Yang, M. Zhang, W. D. Zhang, D. H. Zhao and W. Yuan (NAOC, CAS), on behalf of the LEIA and Einstein Probe team Queries: ep_ta@bao.ac.cn Posted: 11 Nov 2022; 12:51 UT Subjects:X-ray, Star, Transient 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 keV is 1.05(+/-0.02)e-10 erg/s/cm2, which seems to show a tendency of decline compared with the previous LEIA observations. The source is bright with a peak 0.5-4 keV flux of 5.0 (+/-1.3) e-10 erg/s/cm2, 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. LEIA (Lobster Eye Imager for Astronomy, Zhang et al, ApJL submitted) is a soft X-ray Lobster-eye imager (0.5 - 4.0 keV) with a FoV of 340 square degrees aboard the SATech-01 satellite of the CAS, launched on July 27, 2022. The above result is preliminary and the final result will be published elsewhere. ------------------------------------------------------------------------------ Password Certification: Yuan Liu (liuyuan@bao.ac.cn) https://www.astronomerstelegram.org/?read=15754 ============================================================================== ============================================================================== This is an automatically-generated notice.  You can remove yourself permanently from receiving both the Daily Email Digest and Instant Email Notices from The Astronomer's Telegram by following this link: https://www.astronomerstelegram.org?unsubscribe&confirmation=8a5aa7be0259856f83db9aed05783e4c&address=hsun@nao.cas.cn