[vsnet-grb-info 1833] GRB 050724: optical and near-IR observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3673
SUBJECT: GRB 050724: optical and near-IR observations
DATE:    05/07/25 02:38:16 GMT
FROM:    Javier Gorosabel at LAEFF-INTA, Madrid  <jgu at laeff.esa.es>

A.J. Castro-Tirado, J. Gorosabel, A. de Ugarte Postigo,
S. Guziy and M. Jelínek (IAA-CSIC),  M. Karrer (Obs. 
de Geneve), H.-J. Roeser (MPI Heidelberg), N. Elías-Rosa 
(Obs. Astr. di Padova), O. Bogdanov (Nikolaev State Univ.)
and A. Aguirre (CAHA Almería) 

report:

"We have imaged a 6' x 6' region centred on the SWIFT/BAT 
error box for the short/hard GRB 050724 (Covino et al. 
GCNC 3665) with the  1.2-m Mercator telescope (+ Merope) at 
the Observatorio del Roque de los Muchachos on La Palma 
starting on July 24.890 UT (i.e. 8.8 hours after the
GRB) under good meteorological conditions. Within 
the refined SWIFT/XRT position (Romano et al. GCNC 3669), 
the co-added R-band image (5400 s exposure time) shows a 
source close to the center of the 6.3 arcsec radius error 
box, labelled as A by Bloom et al. (GCN Circ. 3672). 
Coordinates yield:  RA(2000) = 16 24 44.96, Dec(2000) 
= -27 32 23.6 (+/- 0.5"). We measure R = 22.40 +/- 0.13
using the USNO-A2.0 star at RA(2000) = 16 24 44.55, Dec(2000)
= -27 32 59.9.  This source is blue, since it is barely 
detected in contemporaneous J- and K-band images obtained 
at the 3.5-m telescope (+ Omega2000) at the German-Spanish 
Calar Alto Observatory and in H-band frames obtained at the 
3.5-m Telescope Nazionale Galileo (+ NICS) on La Palma. The 
colours of objects B and C are also consistent with being 
blue, in contrast to the redder galaxy labelled D. Further 
observations are needed to confirm whether any of these 
objects has any relationship to GRB 050724."  

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