Astron. Astrophys. 336, L95-L99 (1998)

Letter to the Editor

Optical and near-infrared follow-up observations of GRB980329

E. Palazzi ¹, E. Pian ¹, N. Masetti ¹, L. Nicastro ², P. Vreeswijk ³, T.J. Galama ³, P. Groot ³, F. Frontera ^{1, 4}, M. Della Valle ⁵, C. Lidman ⁶, C. Kouveliotou ⁷, G. Pizzichini ¹, J. van Paradijs ^{3, 8}, H. Pedersen ⁹, F. Mannucci ¹⁰, M. Di Martino ¹¹, A.H. Diercks ¹², E.W. Deutsch ¹², L. Amati ¹³, S. Benetti ¹⁴, A.J. Castro-Tirado ^{15, 16}, J. Clasen ¹⁷, E. Costa ¹³, D. Dal Fiume ¹, R. Falomo ¹⁸, M. Feroci ¹³, J. Fynbo ¹⁹, J. Heise ²⁰, J.J.M. in 't Zand ²⁰, L. Piro ¹³, C. Robinson ⁷, M. Tornikoski ²¹, E. Valtaoja ²², M.R. Zapatero-Osorio ²³, D. Lamb ²⁴, J. Quashnock ²⁴ and D. Van den Berk <sup>25

1</sup> Istituto Tecnologie e Studio Radiazioni Extraterrestri, CNR, Via Gobetti 101, I-40129 Bologna, Italy
² Istituto di Fisica Cosmica con Applicazioni all'Informatica, CNR, Via U. La Malfa 153, I-90146 Palermo, Italy
³ University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
⁴ Department of Physics, University of Ferrara, Via Paradiso 11, I-44100 Ferrara, Italy
⁵ Department of Astronomy, University of Padova, V. Dell'Osservatorio 5, I-35122 Padova, Italy
⁶ European Southern Observatory, Casilla 19000, Santiago, Chile
⁷ Universities Space Research Association, Huntsville, AL, USA
⁸ University of Alabama in Huntsville, 35899 AL, USA
⁹ Copenhagen University Observatory, Juliane Maries Vej 30, DK 2100 Copenhagen, Denmark
¹⁰ Centro per l'Astronomia Infrarossa e lo Studio del Mezzo Interstellare, CNR, Largo E. Fermi 5, I-50125 Arcetri, Italy
¹¹ Torino Astronomical Observatory, Pino Torinese, Italy
¹² Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195
¹³ Istituto di Astrofisica Spaziale CNR, Via del Fosso del Cavaliere, I-00131 Roma, Italy
¹⁴ Telescopio Nazionale Galileo, La Palma, Canary Islands, Spain
¹⁵ Laboratorio de Astrofisica Espacial y Fisica Fundamental (LAEFF-INTA), P.O. Box 50727, E-28080, Madrid, Spain
¹⁶ Instituto de Astrofisica de Andalucia (IAA-CSIC), P.O. Box 03004, E-18080, Granada, Spain
¹⁷ Nordic Optical Telescope, La Palma, Canary Island, Spain
¹⁸ Astronomical Observatory of Padova, V. Dell'Osservatorio 5, I-35122 Padova, Italy
¹⁹ Institute of Physics and Astronomy, Aarhus, Denmark
²⁰ Space Research Organization in the Netherlands, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
²¹ Metsähovi Radio Observatory, Helsinki, Finland
²² Tuorla Observatory, Turku, Finland
²³ Instituto de Astrofisica de Canarias, Via Lactea, La Laguna, Tenerife, Spain
²⁴ Department of Astronomy & Astrophysics, University of Chicago, 5640 South Ellis Av., Chicago, IL 60637, USA
²⁵ Mc Donald Observatory, University of Texas, RLM 15.308, Austin, TX 78712-1083, USA

Received 15 June 1998 / Accepted 2 July 1998

Abstract

We imaged the field of GRB980329 in the optical and in the near-infrared starting 20 hours after the event, at the ESO NTT, at the NOT, at the APO and at the TIRGO. In the first night we detect an object of within the BeppoSAX NFI error box at the same position as a transient VLA source proposed as the radio afterglow of this GRB. The source faded by magnitudes in 2.1 days, similarly to the decays of previous GRB optical afterglows. This transient is likely the optical counterpart of GRB980329. In the near-infrared we detect signal at 2- significance, whose position is only marginally consistent with that of the VLA source. The spectrum of the transient bears the signatures of substantial absorption within the GRB host galaxy. The afterglow energetics are interpreted as synchrotron radiation from an expanding blast wave.

Key words: gamma-rays: bursts radiation mechanisms: non thermal

Send offprint requests to: eliana@tesre.bo.cnr.it

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations and Results
  • 2.1. Optical
  • 2.2. Near-infrared
• 3. Discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: July 27, 1998
helpdesk.link@springer.de