GCN Circular 39553

Subject

EP250302a: Montarrenti Observatory optical detection

Event

EP250302a

Date

2025-03-02T23:05:33Z (8 months ago)

From

Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini@iol.it>

Via

Web form

S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy, part of UAI/SSV-GRB section), M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy) and K. Kalinowski (Aarhus University, Department of Physics and Astronomy) report:

we observed the field of the X-ray transient EP250302a (Einstein Probe mission, Trigger ID 01709132186) with the automated and remoted 0.53m Ritchey-Chretien telescope at Montarrenti Observatory (Siena, Italy, IAU code C88).
The observations were started at 2025-03-02 20:40:11 UT (approximately 5 hours after the EP-WXT trigger) stacking 50x40s calibrated Rc-band CCD images.
 
We detect an optical transient candidate at the position reported by Zhu et al. (GCN 39550Loading...
 
 ). Preliminary photometry was obtained using nearby PanSTARRS stars as follows: 

Observation Mid-Time  	T-T0 (hr)       Exposure        Filter      Mag.       Err.
2025-03-02 20:57:42 UT 	  5.35	   	 50x40s		 Rc        20.36     +/-0.08

consistent with other observation reported by Busmann et al., GCN 39551Loading...
 
 .

Magnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations. No correction for galactic dust extinction was applied.

Further observations are ongoing.