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Astron. Astrophys. 348, L5-L8 (1999)

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Letter to the Editor

ESO deep observations of the optical afterglow of GRB 990510 *

Gian Luca Israel **  1, Gianni Marconi 1, Stefano Covino 2, Davide Lazzati 2,3, Gabriele Ghisellini 2, Sergio Campana[FORMULA]  2, Luigi Guzzo 2, Gianantonio Guerrero 2 and Luigi Stella[FORMULA]  1

1 Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monteporzio Catone (Roma), Italy
2 Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (Lecco), Italy
3 Universitá degli Studi, via Celoria 16, I-20133 Milano, Italy

Received 14 June 1999 / Accepted 25 June 1999


We present the results of optical observations of the GRB 990510 field carried out at different epochs from European Southern Observatory (ESO) telescopes. Deep observations, down to a limiting magnitude of about 27 and 24 in the Bessel-R and Gunn-I band, respectively, were obtained between May 16 and 18 from the ESO NTT-SUSI2 telescope and on May 20 from the ESO 3.6 m (EFOSC2) telescope. These observations, together with other published photometric data, allowed to monitor the faint tail of the decaying Optical Transient (OT) associated to the GRB 990510. We discuss the light curves in the different filters (V, R and I) in the light of the recently proposed decay laws. No obvious host associated to the GRB 990510 optical afterglow was found in the R and I band images. By comparing the light curves with respect to the theoretical colors of galaxies with different morphology we derived a lower limit of [FORMULA] for the host galaxy.

Key words: galaxies: general – galaxies: photometry – cosmology: observations – gamma rays: bursts

* Partially based on data collected at the ESO VLT-FORS1 (Paranal), NTT-SUSI2 and ESO 3.6 m EFOSC2 (La Silla) telescopes
** Affiliated to I.C.R.A.

Send offprint requests to: Gianluca.Israel@oar.mporzio.astro.it

© European Southern Observatory (ESO) 1999

Online publication: July 16, 1999