0000000000807250
AUTHOR
Hans A. Krimm
Swift Observations of GRB 070110: An Extraordinary X-Ray Afterglow Powered by the Central Engine
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 s…
The Mouse That Roared: A Superflare from the dMe Flare Star EV Lac Detected by Swift and Konus-Wind
We report on a large stellar flare from the nearby dMe flare star EV Lac observed by the Swift and Konus-Wind satellites and the Liverpool Telescope. It is the first large stellar flare from a dMe flare star to result in a Swift trigger based on its hard X-ray intensity. Its peak f_X from 0.3--100 keV of 5.3x10^-8 erg/cm2/s is nearly 7000 times larger than the star's quiescent coronal flux, and the change in magnitude in the white filter is >4.7. This flare also caused a transient increase in EV Lac's bolometric luminosity (L_bol) during the early stages of the flare, with a peak estimated L_X/L_bol ~3.1. We apply flare loop hydrodynamic modeling to the plasma parameter temporal changes …