TITLE:   GCN CIRCULAR
NUMBER:  20549
SUBJECT: GRB 170127B: NOT r-band upper limits
DATE:    17/01/27 21:08:30 GMT
FROM:    Zach Cano at U of Iceland  <zewcano@gmail.com>

​Z. Cano (IAA-CSIC), K. E. Heintz (Univ. Iceland & DARK/NBI), D. Malesani
(​DARK/NBI and DTU Space​)​ & R. Tronsgaard (NOT) report on behalf of a
larger collaboration:

We observed the field of short-duration GRB 170127B (Cannizzo et al.; GCN
Circ. 20540) with the 2.5-m Nordic Optical Telescope equipped with ALFOSC,
starting at 19:48:56 UT on 27 January 2017 (4.59 hrs from detection).  We
obtained 3x300 s in the r-band.  In our co-added image no new object is
detected in the XRT error circle to the following limit:

Filter    t-t0 (hr)     magnitude (AB)
-------------------------------------------
  r        4.73           >23.4

The r-band upper limit is for an isolated point source in the GRB field,
which is calibrated to local Pan-STARRS standards in the field.  This upper
limit is not corrected for foreground extinction (E(B-V) = 0.02 mag,
Schlegel et al. 1998).