[vsnet-grb-info 3072] GRB 060323: BVRI observations at Tautenburg, aftreglow candidate

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4909
SUBJECT: GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
DATE:    06/03/23 23:17:25 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann at tls-tautenburg.de>

D. A. Kann,  B. Stecklum (TLS Tautenburg) report:

The field of GRB 060323 (Vetere et al., GCN 4904) was observed with the 1.34m 
Tautenburg Schmidt telescope under excellent conditions in BVRcIc.

The observation log is the following:

Midtime	Exp		Filter	lim. Mag

0.1948		6 * 600 s	Ic	21.8
0.2227		1 * 600 s	Rc	22.5
0.2309		1 * 600 s	V	22.5
0.2385		1 * 600 s	B	22.5

Limiting magnitudes were derived via comparison with SDSS pre-burst observations 
(Cool et al., GCN 4905).

For the star at

RA= 174.38742 (11:37:32.98)
Dec = +50.02251 (+50:01:21.04)

I derive via the transformation equations of Lupton (2005) and the SDSS 
photometry:

B = 19.187
V = 18.848
Rc = 18.654
Ic = 18.002

with typical erros of 0.03 mags. Aperature photometry instrumental magnitudes are 
then compared with the magnitudes of sources near the detection limit. The limiting 
magnitudes may be improved with further analysis.

There is no source detected at the position of the possible UVOT afterglow (Vetere 
et al., GCN 4904).

At the position of the X-ray afterglow (Kennea et al., GCN 4908), we detect a faint 
source (Rc ~ 21) at

RA= 11:37:44.56
Dec = +49:58:59.8

that is not visible in the SDSS (limiting mag ~ r = 23).

We suggest this source as the possible afterglow of GRB 060323.

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