The Giant X-ray Flare of Grb 050502b: Evidence for Late-time Internal Engine Activity
نویسندگان
چکیده
Until recently, X-ray flares during the afterglow of gamma-ray bursts (GRBs) were a rarely detected phenomenon; thus, their nature is unclear. During the afterglow of GRB 050502B, the largest X-ray flare ever recorded rose rapidly above the afterglow light curve detected by the SwiftX-Ray Telescope. The peak flux of the flare was >500 times that of the underlying afterglow, and it occurred >12 minutes after the nominal prompt burst emission. The fluence of this X-ray flare, (1:0 0:05) ; 10 6 ergs cm 2 in the 0.2–10.0 keVenergy band, exceeded the fluence of the nominal prompt burst. The spectra during the flare were significantly harder than those measured before and after the flare. Later in time, there were additional flux increases detected above the underlying afterglow, as well as a break in the afterglow light curve. All evidence presented below, including spectral and, particularly, timing information during and around the giant flare, suggests that this giant flare was the result of internal dissipation of energy due to late central engine activity, rather than an afterglow-related effect. We also find that the data are consistent with a second central engine activity episode, in which the ejecta is moving slower than that of the initial episode, causing the giant flare and then proceeding to overtake and refresh the afterglow shock, thus causing additional activity at even later times in the light curve. Subject headinggs: gamma rays: bursts — X-rays: bursts
منابع مشابه
5 The Giant X - ray Flare of GRB 050502 B : Evidence for Late - Time Internal Engine Activity
Until recently, X-ray flares during the afterglow of gamma ray bursts (GRBs) were a rarely detected phenomenon, thus their nature is unclear. During the afterglow of GRB 050502B, the largest X-ray flare ever recorded rose rapidly above the afterglow lightcurve detected by the Swift X-ray Telescope. The peak flux of the flare was > 500 times that of the underlying afterglow, and it occurred at >...
متن کاملOptical / infrared flares of GRB 080129 from late internal shocks
Strong optical and near-infrared (NIR) flares were discovered in the afterglow of GRB 080129. Their temporal behaviors, the sudden emergence and the quick disappearance, are rather similar to that of many X-ray flares (for instance, the giant flare of GRB 050502B). We argue that the optical/NIR flares following GRB 080129 are a low energy analogy of the X-ray flares and the most likely interpre...
متن کاملX-ray Flares: Late Internal and Late External Shocks
We analyze several recently detected gamma-ray bursts (GRBs) with late X-ray flares in the context of late internal shock and late external shock models. We find that the X-ray flares in GRB 050421 and GRB 050502B originate from late internal shocks, while the main X-ray flares in GRB 050406 and GRB 050607 may arise from late external shocks. Under the assumption that the central engine has two...
متن کاملLate internal shock model for bright X - ray flares in Gamma - ray Burst afterglows and GRB 011121
We explore two possible models which might give rise to bright X-ray flares in GRBs afterglows. One is an external forward-reverse shock model, in which the shock parameters of forward/reverse shocks are taken to be quite different. The other is a so called " late internal shock model " , which requires a refreshed unsteady relativistic outflow generated after the prompt γ−ray emission. In the ...
متن کاملLate internal shock model for the bright X-ray flares in GRB afterglows
We explore two possible models which might give rise to bright X-ray flares in GRB afterglows. One is an external forward-reverse shock model, in which the shock parameters of forward/reverse shocks are taken to be quite different. The other is a so called “late internal shock model”, which requires a refreshed unsteady relativistic outflow generated after the prompt γ−ray emission. In the forw...
متن کامل