Back
GCN Circular 31870

Subject
GRB 220408A: RATIR Optical and NIR Observations
Date
2022-04-10T17:38:55Z (2 years ago)
From
Alan M Watson at UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Eleonora Troja (GSFC), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), Rosa L. Becerra (UNAM), Simone Dichiara (UMD), and Oc��lotl L��pez (UNAM) report:

We observed the field of GRB 220408A (Caputo et al., GCN Circ. 31848Not found
 
 
) with the Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir from 2022/04 9.13 to 2022/04 9.49 UTC (20.98 to 29.45 hours after the BAT trigger), obtaining a total of 3.27 hours exposure in the r and i bands and 2.10 hours exposure in the Z, Y, J, and H bands.

For a source within the Swift-XRT error circle, in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following weak detection and 3-sigma upper limits:

  r	> 23.76
  i	> 23.45
  Z	> 21.36
  Y	> 22.04
  J	> 21.79
  H	= 21.27 +/- 0.23

These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We note that while we have a formal detection in H, the large errors call it into doubt.

Our limit in r is consistent with the fainter and slightly earlier detection at r = 24.1 reported by Zhu et al. (GCN Circ. 31864Not found
 
 
).

We thank the staff of the Observatorio Astron��mico Nacional in San Pedro M��rtir.