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GCN Circular 39446

Subject

GRB 250221A: TNOT detection of the optical counterpart

Date

2025-02-24T09:24:45Z (19 days ago)

Edited On

2025-02-24T14:15:51Z (19 days ago)

From

Xiaofeng Wang at Tsinghua University <wang_xf@mail.tsinghua.edu.cn>

Edited By

Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Xiaofeng Wang at Tsinghua University <wang_xf@mail.tsinghua.edu.cn>

Via

Web form

A. Iskandar（XAO), H.-C. Zhu (THU)，X.-F. Wang（THU), L.-T. Wang (XAO), and Shengyu Yan(THU) report the optical detection of the afterglow of GRB 250221A (Francile et al., GCN 39395

; Caputo et al., GCN ; Watson et al., GCN ; Melandri et al., GCN ; Shilling et al., GCN ; Guo et al., GCN ; Muenter et al., GCN ; Palmerio et al., GCN ; Pankov et al., GCNs ,,,; Ghosh et al., GCN ).

We obtained the r-band images (about 2.40 days after the burst) with the 80~cm Tsinghua-Nanshan Optical Telescope (TNOT) located at Nanshan Station of Xinjiang Astronomy Observatory, starting on 2025-02-23 (UT) 13:05:49. The afterglow is clearly detected on the stacked images, with the following magnitude:

r = 20.46 +- 0.17 mag (MJD =60698.5457)

The above photometric result is calibrated against the Pan-STARRS catalog without a correction for the Galactic extinction.