Near-infrared detection and optical follow-up of the GRB990705 afterglow

• Main Authors: Masetti, N., Palazzi, E., Pian, E., Hunt, L. K., Méndez, M., Frontera, F., Amati, L., Vreeswijk, P. M., Rol, E., Galama, T. J., van Paradijs, J., Antonelli, L. A., Nicastro, L., Feroci, M., Marconi, G., Piro, L., Costa, E., Kouveliotou, C., Castro-Tirado, A. J., Falomo, R., Augusteijn, T., Böhnhardt, H., Lidman, C., Vanzi, L., Merrill, K. M., Kaminsky, C. D., van der Klis, M., Heemskerk, M. H. M., van der Hooft, F., Kuulkers, E., Pedersen, H., Benetti, S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2000
• Subjects: GAMMA RAYS: BURSTS; RADIATION MECHANISMS: NON-THERMAL; GALAXIES: GENERAL; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/11370/57a3fca1-d278-452b-bb74-6ff70b3c1bca; https://research.rug.nl/en/publications/57a3fca1-d278-452b-bb74-6ff70b3c1bca; http://adsabs.harvard.edu/abs/2000A%26A.354.473M

Optical and near-infrared observations of the GRB990705 error box were carried out with ESO telescopes at La Silla and Paranal in Chile and with the NOAO SPIREX 0.6-meter telescope in Antarctica. We detected the counterpart of this GRB in the near-infrared H band and optical V band. The power-law decline of the near-infrared lightcurve is rather steep with a decay index alpha =~ 1.7 in the first hours, and a possible steepening after one day. Broadband spectral analysis of the optical/near-infrared afterglow suggests that this GRB took place in a high density environment. A deep optical image obtained at Antu (VLT-UT1) about 5 days after the GRB trigger shows at the position of the transient an extended object which might be the host galaxy of GRB990705. Based on observations collected at the European Southern Observatory, La Silla and Paranal, ChileBased on observations collected with NOAO facilities