TITLE:   GCN CIRCULAR
NUMBER:  44356
SUBJECT: GRB 260412A: LCOGT Optical Upper Limits
DATE:    26/04/20 17:36:58 GMT
FROM:    Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>

R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:

We observed the GRB260412A field (Fermi GBM Team, GCN 44275; Wang et al., GCN 44276) with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory, South Africa site, on April 12, from 17:13 to 17:26 UT (corresponding to 11.0 to 11.2 hours after the trigger time) and with the LCOGT 1-meter Sinistro instrument at the Cerro Tololo Interamerican Observatory, Chile site, from 23:20 to 23:52 (17.1 to 17.7 hours after the trigger time) with the Bessel I and R filters.

We performed a series of 3x300s exposures in I-band and 1x100s exposure in R-band due to a scheduling interruption, and then 3x300s in I-band and R-band for the second epoch.  We do not detect an uncatalogued source within the SVOM error region (Wang et al., GCN 44276), consistent with other optical upper limits (Lipunov et al., 44280).

The following 5-sigma upper limits are calculated using the USNO-B1.0 catalog as reference:

Epoch 1:
I>20.7
R>17.3

Epoch 2:
I>21.0
R>22.6

These magnitudes are not corrected for galactic extinction.