EP260417b
GCN Circular 44342
V. Vijaykumar (IITB), T. Mohan (IITB), V. Swain (IITB), D. Eappachen (IIA), S. Patil (IITB), A.P. Saikia (IITB), V. Bhalerao (IITB), G.C. Anupama (IIA), S. Barway (IIA) and R. Norbu (IAO) report on behalf of the GIT team:
We observed the field of EP260417b detected by Einstein Probe (Ni et al., GCN 44323), with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2026-04-18 19:04:51 (UTC), i.e., 1.74 days after the trigger, and obtained a single exposure in the r' filter. We did not detect any transient in our image within the uncertainty region of source position reported by EP. The photometric upper limit is as follows:
| MJD (mid) | Filter | tmid-t0 (hours) | Exposure Time (sec) | Upper limit (AB) |
|---|---|---|---|---|
| 61148.797 | r' | 41.78 | 420 | 19.3 |
The measurement is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular 44323
K. R. Ni (CCNU), Y. Q. Zhao (USTC; PRIC), Y. L. Wang (NAO, CAS; ICE, CSIC) and Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team:
We report on the detection of a fast X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260417b. The ground analysis of the WXT data shows that the event started at T0 = 2026-04-17T01:21:04 (UTC) and lasted for around 230 s. The WXT position of the source is R.A. = 151.114 deg, DEC = 51.964 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic).
A follow-up observation with the Follow-up X-ray Telescope (FXT) on board EP has been scheduled. Further information will be updated when the telemetry data is received.
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).