N. Masetti, E. Palazzi (ITeSRE, CNR, Bologna), E. Pian (Oss. Astron. Trieste),
S. Desidera, E. Giro, A. Frigo (Oss. Astron. Asiago), R. Falomo (Oss.
Astron. Padova), A. Zacchei, A. Magazzu, F. Ghinassi, and M. Pedani (TNG),
on behalf of a larger collaboration, report:
"We acquired optical R-band images of the BeppoSAX NFI error box
(Frontera et al., GCN #950) of GRB010214 (Guidorzi et al., GCN #951)
with the 1.8m "Copernicus" telescope (+AFOSC) located at Cima Ekar in
Asiago (Italy). We also observed this field in B, V and R at the
Canary Islands with TNG+Dolores.
Total exposure times, limiting magnitudes and seeing for each of these
observations are reported in the table below.
telescope date band exptime 3-sigma seeing
(UT) (min) limit (")
Asiago 2001 Feb 16.19 R 30 ~22.5 2.0
TNG " " 16.23 R 10 ~23.5 1.2
TNG " " 16.24 V 10 ~24 1.2
TNG " " 16.25 B 15 ~24 1.2
Asiago " " 21.11 R 35 ~21.5 4.0
Photometric calibration was performed using the USNO-A2.0 catalog star
U1350_09300715, which has magnitudes R = 18.3 and B = 19.3 and coordinates
(J2000) RA = 17 40 53.13; Dec = +48 34 08.8. Using those magnitudes and
assuming a starlike blackbody spectrum for this object, we estimated
its V magnitude to be 18.7.
We could not tie our photometry to the USNO star used by Zhu & Xue
(GCN #938) because it was saturated in all of our images.
The comparison between the two Asiago images does not reveal any object
with significant brightness variation down to a 3-sigma limiting
magnitude R ~ 21.5 inside the NFI error box.
The IR object reported by Di Paola et al. (GCN #939) is detected in TNG V
and R images at magnitudes V = 23.8 +- 0.3 and R = 22.02 +- 0.05
(excluding zero-point calibration uncertainties), while it is
not detected in the B band down to the frame limit (B > 24).
The object is also detected in the first Asiago image at an R magnitude
consistent with that measured at TNG.
This very red object is not present on the DSS-II as its R magnitude
is below the limit of this survey.
Based on our data we cannot confirm that it does not vary. But, given its
constancy in the J band reported by Antonelli et al. (GCN #945), and the
fact that it lies ~2.4 arcmin from the NFI error box, we can confidently
say that this object is unlikely the counterpart of GRB010214.
Also, we do not detect any object down to the frame limits in all images
at the position reported by Zhu & Xue (GCN #938).".
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