Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 25657

GRB 190829A: Liverpool Telescope observations of a slow supernova rise
2019-09-04T16:36:59Z (5 years ago)
Daniel Perley at Liverpool JMU <>
D. A. Perley and A. M. Cockeram (LJMU) report:

We obtained another epoch of r/i/z imaging of the optical counterpart of 
GRB 190829A (Dichiara et al., GCN 25552; Lesage et al., GCN 25575; Xu et 
al., GCN 25555) with IO:O on the Liverpool Telescope Telescope on 
2019-09-04 between 04:43 and 05:32 UT.  Image subtraction was performed 
using PS1 imaging as a template.  We report the following photometry:

  t-t0    filt   mag        unc
  ------  ----   -----     ----
  5.3707  i      21.32 +/- 0.09
  5.3941  z      20.61 +/- 0.10

This is consistent with a continued, slight rise compared to our 
previous two LT epochs (e.g., i = 21.45 at t = 4.29 days; GCN 25623) and 
with our earlier interpretation of the light curve flattening as the 
appearance of an associated supernova.  Spectroscopic confirmation is 
still necessary to solidify this interpretation.

We note that our z-band measurement is 1 magnitude fainter than that 
reported by Bolmer et al. (GCN 25651) at a similar epoch, and we do not 
confirm the sharp, short-timescale rise that they report.  It is 
possible that the difference arises due to lack of host galaxy 
subtraction in the GROND photometry.

Looking for U.S. government information and services? Visit