TITLE:   GCN CIRCULAR
NUMBER:  17698
SUBJECT: GRB 150413A: optical observations
DATE:    15/04/14 12:12:40 GMT
FROM:    Klaas Wiersema at U Leicester  <kw113@leicester.ac.uk>

I. van de Stadt (AWSV Metius, Alkmaar, The Netherlands) and
K. Wiersema (U. of Leicester) report:

We observed the field of GRB 150413A (Markwardt  et al. GCN 17688;
Ivanov et al., GCN 17689) using the ABT, a 10-inch remote controlled
observatory in Alkmaar, The Netherlands. In a series of I band exposures,
with midpoint 0.55 days after burst, the afterglow is not detected, with
a 5-sigma upper limit of 18.7 mag (calibrated using APASS field stars and
the Jordi et al. (2005) conversions). This limit is in agreement with the
light curve break seen by Schmalz et al. (GCN 17695).