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VLT observations of GRB 990510 and its environment

K. Beuermann·F. V. Hessman·K. Reinsch·H. Nicklas·P. M. Vreeswijk·T. J. Galama·E. Rol·J. van Paradijs·C. Kouveliotou·F. Frontera·N. Masetti·E. Palazzi·E. Pian
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Abstract

We present BVRI photometry and spectrophotometry of GRB990510 obtained with the ESO VLT/Antu telescope during the late decline phase. Between days 8 and 29 after the burst, the afterglow faded from R=24.2 to ~26.4. The spectral flux distribution and the light curve support the interpretation of the afterglow as synchrotron emission from a jet. The light curve is consistent with the optical transient alone but an underlying SN with maximum brightness R>27.4 or a galaxy with R>27.6 (3-sigma upper limits) cannot be ruled out. To a 5-sigma detection threshold of R=26.1, no galaxy is found within 6'' of the transient. A very blue V~24.5 extended object which may qualify as a starburst galaxy is located 12'' SE, but at unknown redshift.

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K. Beuermann, F. V. Hessman, K. Reinsch, H. Nicklas, P. M. Vreeswijk, T. J. Galama, E. Rol, J. van Paradijs, C. Kouveliotou, F. Frontera, N. Masetti, E. Palazzi, E. Pian. 1999-09-02. VLT observations of GRB 990510 and its environment. https://arxiv.org/abs/astro-ph/9909043

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