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GCN Circular 37667

Subject

GRB241001A: optical afterglow candidate

Date

2024-10-02T06:13:52Z (2 days ago)

Edited On

2024-10-03T14:25:12Z (5 hours ago)

From

Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>

Edited By

Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>

Via

Web form

Luca Izzo (INAF/OACn) and Daniele B. Malesani (DAWN/NBI and Radboud Univ.) report:

We observed the field of the SVOM/ECLAIRs GRB 241001A (Dagoneau et al., GCN #37655Not found
 
 
) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located in Sutherland, South Africa. Observations started on 2024 October 1st at 18:40:35 UT (1.53 hr after the GRB trigger). We obtained a series of 3x120 s images in the SDSS-r filter and 5x120s images in the PS1-z filter.

The stacked r-band image covers the entire statistical ECLAIRs error region and it is slightly affected by a bad telescope tracking. We notice the presence of a faint source within the error box of the Swift-XRT afterglow candidate source no. 2 (Evans, GCN #37659Not found
 
 
) at coordinates (J2000.0):

RA = 01:22:12.71
Dec = -43:28:31.8

No source is visible in archival images from the Legacy Survey DR10 at this location.

We measure a preliminary magnitude of r = 20.7 +/- 0.2 mag (AB), calibrated against nearby stars from the Legacy Survey DR10 catalog. Further analysis is on-going.

Coupled with some evidence of fading of the X-ray counterpart (https://www.swift.ac.uk/ToO_GRBs/00021719/Source2/curve), and given the lack of archival detection, we suggest this source to be the afterglow of GRB 241001A.
  
This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719.