The early optical afterglow and non-thermal components of GRB 060218

Emery S. W. K., Page M. J., Breeveld A. A., Brown P. J., Kuin N. P. M., Oates S. R., ...More

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol.484, no.4, pp.5484-5498, 2019 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 484 Issue: 4
  • Publication Date: 2019
  • Doi Number: 10.1093/mnras/stz373
  • Journal Name: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.5484-5498
  • Keywords: radiation mechanisms: non-thermal, radiation mechanisms: thermal, gamma-ray burst: general, gamma-ray burst: individual: GRB 060218, GAMMA-RAY BURST, SHOCK BREAKOUT, NEUTRON-STAR, SUPERNOVA, SPECTRA, SWIFT, LUMINOSITY, GRB-060218, POLARIZATION, CALIBRATION
  • Istanbul University Affiliated: Yes

Abstract

We re-examine the UV/optical and X-ray observations of GRB 060218 during the prompt and afterglow phases. We present evidence in the UV/optical spectra that there is a synchrotron component contributing to the observed flux in the initial 1350 s. This result suggests that GRB 060218 is produced from a low-luminosity jet, which penetrates through its progenitor envelope after core collapse. The jet interacts with the surrounding medium to generate the UV/optical external shock synchrotron emission. After 1350 s, the thermal radiation in the UV/optical and X-ray becomes the dominant contribution to the observed flux. The UV/optical and X-ray spectra at 1350-10 000 s can be fitted with a spherically outflowing blackbody model, with an additional power-law component to the model at X-ray energies.