[vsnet-grb-info 15262] GRB 140709A: BOOTES-2 and OSN optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16554
SUBJECT: GRB 140709A: BOOTES-2 and OSN optical observations
DATE:    14/07/09 16:51:28 GMT
FROM:    Juan Carlos Tello at IAA-CSIC  <jtello at iaa.es>

A.J. Castro-Tirado (IAA-CSIC, ISA-UMA), J. Gorosabel (IAA-CSIC, UPV-EHU),
J. C. Tello, R. Cunniffe, A. Gonzalez-Rodriguez, A. Sota, M. Jelinek, S.
Jeong, O. Lara-Gil, S. R. Oates, R. Sanchez-Ramirez (IAA-CSIC, Granada), P.
Kubanek (IP-ASCR, Prague) and S. Pandey (ARIES) report:

Following the detection of GRB 140709A by Swift (Hagen et al., GCNC 16546),
the 0.6m TELMA robotic telescope at the BOOTES-2 astronomical station
Malaga (Spain), responded to the GRB location starting at 01:14:41 UT (i.e.
60s postburst, in the clear filter, 5s integrations), with an upper limit
of R > 16.5. Further optical observations were carried out at the 1.5m OSN
telescope starting on July 9.06-9.12 UT (i.e. 0.37--1.72 hours post GRB). A
source coincident with the enhanced XRT position is found (Evans et al. GCN
16548) at coordinates RA(J2000) = 20:18:38.95,  DEC(J2000) = 51:13:29.6
(+/-0.5") when the 78x60s frames are co-added.  Using USNO-B1.0 as
reference, we measure a Vega magnitude of I = 20.8 (uncorrected for
Galactic reddening), which is the potential optical afterglow. At the
present stage we do not know is the source is fading or not. We also detect
the object reported by RATIR (Butler et al. GCN 16547), which is not
consistent with the position of our candidate. Further observations are
planned.