Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 30385

GRB 210704A: TNG detection of the optical afterglow candidate
2021-07-05T23:15:32Z (3 years ago)
Paolo D'Avanzo at INAF-OAB <>
P. D'Avanzo (INAF-OAB), V. D'Elia (ASI-SSDC), A. Fiorenzano, C. Padilla (INAF-TNG) on behalf of the CIBO collaboration report:

We observed the field of GRB 210704A (Kunzweiler et al., GCN Circ. 30369; Ursi et al., GCN Circ. 30372; Berretta et al., GCN Circ. 30375; 
Prasad et al., GCN 30378; Malacaria et al. GCN 30380), covering the position of the X-ray afterglow reported by D'Ai et al. (GCN Circ. 30379) 
with the Italian 3.6m TNG telescope equipped with the optical camera DOLORES. A series of images were obtained with the r-sdss filter on 
2021-07-05 from 21:13:11 UT to 21:39:50 UT (i.e. about 1.08 days after the burst).  

The optical afterglow candidate reported by Kim et al. (GCN Circ. 30384) is clearly detected at the following position (J2000): 
RA: 10:36:04.92
Dec: +57:12:59.3
(+/- 0.5"). 

With preliminary photometry we derive the following magnitude:
r = 22.13  +/- 0.13 

(AB; calibrated against the SDSS catalogue). 

As noted by  Kim et al. (GCN Circ. 30384), this source is not visible in archival SDSS and Pan-STARRS images.
Looking for U.S. government information and services? Visit