GRB020405 field photometry

GRB020405 BVRI field calibration

1.54Danish + DFOSC

1.54Danish+DFOSC R image

The field of GRB020405 imaged in the R band on 2002 April 5. The OT is at the centre of the image. North is at top, East is to the left; the field size is about 3 x 3 arcmin. Numbers indicate the reference stars whose magnitudes are reported in the table below.

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 #  RA(J2000)    Dec(J2000)    USNO-A2.0    Bmag  Error  Vmag  Error  Rmag  Error   Imag  Error
                 
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 1 13 57 56.916 -31 21 30.79 0525-16811816  19.57  0.01  18.69  0.01  18.17  0.01  17.55  0.01 
 2 13 58 00.214 -31 22 28.86 0525-16813005  19.84  0.01  19.01  0.01  18.48  0.01  17.87  0.01
 3 13 58 05.128 -31 20 52.81 0525-16814757  19.34  0.01  18.85  0.01  18.50  0.02  18.12  0.01
 4 13 58 07.165 -31 22 00.04 0525-16815458  20.09  0.02  19.49  0.01  19.14  0.02  18.72  0.01
 5 13 58 07.212 -31 22 57.50 0525-16815468  18.18  0.01  17.92  0.01  17.72  0.01  17.45  0.01
 6 13 58 07.374 -31 22 50.74 0525-16815530  20.45  0.02  19.35  0.01  18.67  0.01  18.00  0.01
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GCN Circular no. 1388

GRB020405 field photometry at ESO

A. Simoncelli, E. Maiorano (U. Bologna), E. Palazzi, N. Masetti (IASF/CNR, Bologna), E. Pian (INAF, OA Trieste), J. Hjorth (U. Copenhagen), A. Castro-Tirado (IAA-CSIC, Granada), A. Fruchter (STScI, Baltimore), J. Greiner (MPE Garching and AI Potsdam), L. Kaper, E. van den Heuvel (U. Amsterdam), A. Delsanti, M. Billeres (ESO), on behalf of the GRACE Collaboration, report:

"We have acquired BVRcIc photometry for the field of GRB020405 with the Danish 1.54m and NTT 3.58m ESO telescopes at La Silla, Chile.

We placed the photometric data of 6 selected stars, together with an R-band image of the field on which the stars are marked, at the URL:

http://tonno.tesre.bo.cnr.it/~masetti/grb020405_phot.html

The current photometry has a potential external zero-point error of about three percent that needs to be added in quadrature to the Poisson errors given for the magnitudes of the selected stars.

Specifically, the magnitudes of the USNO-A2.0 stars 0525-16813005 and 0525-16815468 (Palazzi et al., GCN #1328; Hjorth et al., GCN #1329), which are labeled as stars #2 and #5 of our sample, are V = 19.01 +- 0.01, R = 18.48 +- 0.01 for the first one and V = 17.92 +- 0.01 for the second.".

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