Abstract for Proposal 086286

XMM-Newton Observations of Jets in Short Gamma-ray Bursts

With the first discovery of a NS merger detected with gravitational wave facilities, and ongoing detections of SGRBs detected with gamma-ray satellites, it is a golden era to make significant progress in merger studies. A critical link between these populations is the production of relativistic jets, and the fraction of mergers that produce relativistic SGRB-like outflows. Deep X-ray observations have played an important role in constraining the collimation of SGRBs, as our current knowledge of the opening angle distribution comes almost exclusively from X-ray observations at >1 day after the burst. Here, we propose for XMM-Newton TOO observations to monitor a SGRB afterglow and constrain its opening angle, which will have significant implications for the energy scales and event rates.

Details on Observing Strategy and Trigger Criteria
We will trigger a pair of observations of a short GRB with a detected X-ray afterglow, to occur at 4-7 and 17-25 days after the burst if (i) FX,XRT>8e-14 erg s^-1 cm^-2 (0.3-10 keV) and (ii) The extrapolated 0.3-10 keV FX at 4 days is >10^-14 erg s^-1 cm^-2. We will trigger within 1 day of the burst for a minimum response time of 3 days.