EP-FXT observation of the optical transient AT2024fkm: no X-ray signal detected
ATel #16582; C. K. Li (IHEP, CAS), H. Y. Liu (NAOC, CAS), S. M. Jia , Y. Chen, W. W. Cui, H. Feng, J. Guan, D. W. Han, W. Li, C. Z. Liu, F. J. Lu, L. M. Song, J. Wang, J. J. Xu, J. Zhang, S. N. Zhang, H. S. Zhao, X. F. Zhao (IHEP, CAS), D. Y. Li, Z. X. Ling, Y. Liu, Z. Z. Lv, H. Sun, Q. Y. Wu, W. Yuan (NAOC, CAS), K. Nandra, A. Rau, P. Friedrich, N. Meidinger, V. Burwitz (MPE), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (UoL) and B. Cordier (CEA), Y. Z. Fan, X. F. Wu (PMO, CAS), X. F. Wang (THU), J. R. Mao (YNAO, CAS) on behalf of the Einstein Probe team
on 11 Apr 2024; 15:02 UT
Credential Certification: Yuan Liu (liuyuan@bao.ac.cn)
Subjects: X-ray, Supernovae
Following the detection of the rapidly fading optical transient AT2024fkm (Brennan et al., AstroNote 2024-92; Smartt et al., AstroNote 2024-93; Karambelkar et al., AstroNote 2024-94), we performed an X-ray observation of AT2024fkm with the Follow-up X-ray Telescope (FXT) on board Einstein Probe (EP).
The observation began on 2024-04-07 13:40:01 UT, about 5 days after the first detection of AT2024fkm, with a total exposure time of about 20 ks. No X-ray source was detected associated with AT2024fkm. We set an upper limit to the X-ray flux as 6.2E-15 erg/s/cm^2 (90% C.L.) in the 0.5-2keV band, assuming an absorbed power-law spectral shape with a photon index of 2 and the Galactic absorption N_H of 1.16E20cm^-2 in the source direction.
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE, and CNES, aimed at enhancing our understanding of transient phenomena across the electromagnetic spectrum.
