[vsnet-grb-info 27227] ZTF21aaeyldq: GROND observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29330
SUBJECT: ZTF21aaeyldq: GROND observations
DATE:    21/01/19 16:38:42 GMT
FROM:    Ana Nicuesa at TLS Tautenburg  <ana at tls-tautenburg.de>

A. Nicuesa Guelbenzu (TLS Tautenburg), A. Rau (MPE Garching),
and S. Klose (TLS Tautenburg) report:

We observed the field of ZTF21aaeyldq/AT2021any (Ho et al., GCN 29305)
with GROND mounted at the 2.2m MPG telescope at the ESO La Silla
Observatory (Chile).

Observations were performed during three epochs. The data were
calibrated against SDSS stars in the field.

In the g' band we measure the following AB magnitudes:

dt/days         mag
1.82415   23.39 +/- 0.11
2.02104   23.47 +/- 0.06
2.87115   23.84 +/- 0.09.

Following Kann et al. (GCN 29321), here we assumed a GRB trigger time
22 minutes before the discovery image (Ho et al., GCN 29305), i.e., at
JD 2459230.77622.

Based on these three epochs, we measure a decay slope of  0.94 +/-
0.05, in agreement with Kann et al. (GCN 29321). There is no evidence
for an underlying host galaxy.

The transient was not detected in the NIR bands.

We thank Sam Kim (PUC) for performing the observations and all people,
in particular P. Eigenthaler, R. Lechaume, A. Hempel, M. Hempel,
T. Schweyer, A. González, involved in bringing GROND back online after
its shutdown due to the Covid 19 pandemia in early 2020.