[vsnet-grb-info 4334] GRB 070220: ART-3 Optical and NIR limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6122
SUBJECT: GRB 070220: ART-3 Optical and NIR limits
DATE:    07/02/21 07:53:10 GMT
FROM:    Ken ichi Torii at Osaka U  <torii at ess.sci.osaka-u.ac.jp>

K. Torii, S. Tanaka, and H. Tsunemi (Osaka U.) report:

 The error region of GRB 070220 (Stamatikos et al. GCN 6114;
Beardmore et al. GCN 6118) was observed with the 14 inch
ART-3a and 0.35 m ART-3b, both located in Toyonaka, Osaka.

 The imaging started at 2007 Feb. 20, 09:27:03 UT (4.7 hours
after the burst) in Ic band (ART-3a), and at 09:55:44 UT in
J band (ART-3b equipped with thermoelectrically cooled
InGaAs array). We do not detect neither optical nor near
infrared counterpart for the X-ray afterglow (GCN 6114,
6118), and derive the following 3 sigma upper limits
relative to USNO-B1.0 I2 and 2MASS J magnitudes.

-----------------------------------------
StartUT		Filter	Limit	Exposure
=========================================
09:53:18	Ic	19.4	60s x 75
09:55:44        J	14.4	20s x 200
11:12:03	Ic	19.4	60s x 100
=========================================