GCN Circular 39569
Subject
EP250302a: NUTTelA-TAO Early Measurments
Date
2025-03-03T12:18:23Z (12 days ago)
From
Toktarkhan Komesh at Nazarbayev University <toktarkhan.komesh@nu.edu.kz>
Via
Web form
T. Komesh (NU), Z. Abdullayev (NU), Z. Maksut (NU), D. Berdikhan (NU), B. Grossan (UCB, NU), M. Krugov (FAI) and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory:
The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at EP250302a on receipt of an automated GCN / EP position alert, observing in Sloan g' and r' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).
We started observations at 15:42:43 UT on 2025-03-02, 399 seconds after the Einstein Probe trigger (Dai et al., GCN 39556). Observations were made in partially cloudy conditions. A new and changing source consistent with the XRT position (Page et al., GCN 38761) was detected. We report the following photometric values for the optical transient:
tc-t0(s) g'(mag) err r'(mag) err exposure_time (s)
--------------------------------------------------------------
424 - 18.36 0.08 50
628 - 18.35 0.08 300
928 - 18.80 0.13 300
1273 - 18.76 0.07 240
1513 - 18.55 0.06 240
1753 - 18.12 0.04 240
1993 - 17.71 0.03 240
2233 - 17.58 0.02 240
2686 - 17.48 0.03 240
2926 - 17.54 0.02 240
3166 - 17.58 0.02 240
3406 - 17.65 0.02 240
3646 - 17.68 0.03 240
3886 - 17.73 0.03 240
4126 - 17.85 0.03 240
4366 - 17.88 0.04 240
4606 - 17.95 0.03 240
4846 - 18.08 0.04 240
5086 - 18.11 0.03 240
5326 - 18.18 0.04 240
5566 - 18.32 0.04 240
5806 - 18.47 0.04 240
6046 - 18.56 0.04 240
6348 18.93 0.05 18.56 0.04 240
6588 18.99 0.06 18.76 0.04 240
6828 19.01 0.05 18.86 0.05 240
7068 19.05 0.05 18.86 0.05 240
7308 19.06 0.05 18.90 0.05 240
7548 19.12 0.05 18.94 0.05 240
7788 19.28 0.07 19.01 0.06 240
8028 19.43 0.08 19.01 0.06 240
8269 19.53 0.08 19.19 0.07 240
8509 19.34 0.06 19.19 0.06 240
tc-t0 = trigger time minus image center time. Calibration was done with 4 bright Pan-STARRS catalog stars on our images.
Our results are in agreement with those reported in previously published circulars (Zhu et. al, GCN 39550; Wu et. al, GCN 39555; Xin et. al, GCN 39558; Pankov et al., GCN 39565).
We caution the reader that these are preliminary results, without color or other corrections, and will likely change in small measure. Please also note that times are approximate.
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NU = Nazarbayev University, Astana, Kazakhstan
UCB = University of California, Berkeley, USA
FAI = Fesenkov Astrophysical Institute, Kazakhstan
This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP26103591). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan.