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

GCN Circular 22029

Subject
GRB 171020A: NOT optical afterglow detection
Date
2017-10-21T00:19:15Z (7 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
D. Malesani (DARK/NBI), M. Stone (Turku Univ.), K. Karhunen (Turku 
Univ.), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), and D. Xu 
(NAOC/CAS), report on behalf of a larger collaboration:

We observed the field of GRB 171020A (Page et al., GCN 22028) with the 
Nordic Optical Telescope equipped with the AlFOSC imager and 
spectrograph. Observations were carried out in the r and z filters, 
starting on 2017 Oct 20.979 UT (22.9 min after the trigger).

Within the XRT error circle, we detect an uncatalogued source at 
coordinates (J2000):

RA = 02:36:59.62
Dec = +15:12:16.0

By comparison with nearby stars from the Pan-STARRS catalog, we measure 
r = 20.98 +- 0.03 AB. As this object is not visible in the deeper, 
archival Pan-STARRS images, and given the coincidence with the X-ray 
counterpart, we suggest this object to be the optical afterglow of GRB 
171020A.
Looking for U.S. government information and services? Visit USA.gov