Radio, millimeter and optical monitoring of GRB 030329 afterglow: constraining the double jet model

¹ Raman Research Institute, Bangalore 560080, India e-mail: resmi@rri.res.in
² Joint Astronomy Programme, Indian Institute of Science, Bangalore 560012, India
³ National Center for Radio Astrophysics, Post Bag 3, Ganeshkhind, Pune 411007, India
⁴ Instituto de Astrofísica de Andalucía, Apartado de Correos, 3.004, 18080 Granada, Spain
⁵ IRAM – Institut de Radio Astronomie Millimétrique, 300 rue de la Piscine, 38406 Saint-Martin d'Hères, France
⁶ Aryabhatta Research Institute of Observational Sciences, Manora Peak, Naini Tal 263129, India
⁷ Indian Institute of Astrophysics, Bangalore 560034, India
⁸ Center for Research & Education in Science & Technology, Hosakote, Bangalore 562114, India
⁹ European Southern Observatory, Alonso de Córdova, Casilla 19001, Chile
¹⁰ Stockholm Observatory, 106 91 Stockholm, Sweden
¹¹ Astronomical Observatory, Nikolaev State University, Nikolskaja, 24, Nikolaev 54030, Ukraine
¹² Space Telescope Science Institute, 3.700 San Martín Dr., Baltimore, MD 21.218-2.463, USA

Received: 12 July 2004
Accepted: 12 April 2005

Abstract

We present radio, millimeter and optical observations of the afterglow of GRB 030329. photometry is presented for a period of 3 h to 34 days after the burst. Radio monitoring at 1280 MHz has been carried out using the GMRT for more than a year. Simultaneous millimeter observations at 90 GHz and 230 GHz have been obtained from the Swedish-ESO Submillimeter Telescope (SEST) and the IRAM-PdB interferometer over more than a month following the burst. We use these data to constrain the double jet model proposed by Berger et al. (2003) for this afterglow. We also examine whether instead of the two jets being simultaneously present, the wider jet could result from the initially narrow jet, due to a fresh supply of energy from the central engine after the “jet break”.