[vsnet-grb-info 24878] GRB 200131A: Further RATIR Optical Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26977
SUBJECT: GRB 200131A: Further RATIR Optical Observations
DATE:    20/02/03 19:22:08 GMT
FROM:    Nat Butler at Az State U  <natbutler at asu.edu>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:

We observed the field of GRB 200131A (Sbarufatti et al., GCN 26953) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)
on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico
Nacional on Sierra San Pedro Mártir from 2020/02 2.10 to 2020/02 2.17
UTC (27.70 to 29.45 hours after the BAT trigger), obtaining a total of
1.42 hours exposure in the r and i bands, and from 2020/02 3.10 to
2020/02 3.12 UTC (51.69 to 52.28 hours after the BAT trigger), obtaining
a total of 0.49 hours exposure in the r and i bands.

The optical transient (Lipunov et al., GCN Circ. 26954, Butler et al.,
GCN Circ. 26957, Strausbaugh et al., GCN Circ. 26959, Gokuldass et al.,
GCN Circ. 26960, Pozanenko et al., GCN Circ. 26964 & 26965) is detected
on 2020/02/02 with:

  r = 21.39 +/- 0.11
  i = 21.39 +/- 0.07

and on 2020/02/03 with:

  r = 22.26 +/- 0.29
  i = 22.45 +/- 0.35

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.