Swift observations of GRB 070110: an extraordinary X-ray afterglow powered by the central engine
Abstract
We present a detailed analysis of Swift multi-wavelength observations of GRB 070110 and its remarkable afterglow. The early X-ray light curve, interpreted as the tail of the prompt emission, displays a spectral evolution already seen in other gamma-ray bursts. The optical afterglow shows a shallow decay up to ~2 d after the burst, which is not consistent with standard afterglow models. The most intriguing feature is a very steep decay in the X-ray flux at ~20 ks after the burst, ending an apparent plateau. The abrupt drop of the X-ray light curve rules out an external shock as the origin of the plateau in this burst and implies long-lasting activity of the central engine. The temporal and spectral properties of the plateau phase point towards a continuous central engine emission rather than the episodic emission of X-ray flares. We suggest that the observed X-ray plateau is powered by a spinning down central engine, possibly a millisecond pulsar, which dissipates energy at an internal radius before depositing energy into the external shock.
Cite
@article{arxiv.astro-ph/0702220,
title = {Swift observations of GRB 070110: an extraordinary X-ray afterglow powered by the central engine},
author = {E. Troja and G. Cusumano and P. O'Brien and B. Zhang and B. Sbarufatti and V. Mangano and R. Willingale and G. Chincarini and J. P. Osborne and F. E. Marshall and D. N. Burrows and S. Campana and N. Gehrels and C. Guidorzi and H. A. Krimm and V. La Parola and E. W. Liang and T. Mineo and A. Moretti and K. L. Page and P. Romano and G. Tagliaferri and B. B. Zhang and M. J. Page and P. Schady},
journal= {arXiv preprint arXiv:astro-ph/0702220},
year = {2010}
}
Comments
10 pages, 5 figures, accepted for publication in ApJ. Main change: refined analysis of optical data