Abstract for Proposal 090338
The collimation and energetics of short GRBs: searching for jet-breaks with XMM
At the dawn of gravitational wave astronomy, the degree of collimation
of short GRBs is a key issue, bearing critical information on the true
energy release and event rate of neutron star mergers. The geometry of
the GRB outflow can be constrained through afterglow observations, and,
in particular, through the measurement of the so-called "jet-breaks". The
intrinsic faintness of short GRB afterglows prevents jet-breaks to be
detected with Swift/XRT observations. We propose to overcome this limit by
triggering deep XMM-Newton ToOs observations of short GRB afterglows. We
will leverage the X-ray observations with an intense follow-up campaign,
including several ground-based and request to complement it with JVLA
radio observations.
Details on Observing Strategy and Trigger Criteria
Trigger Criteria: short GRB with X-ray afterglow brighter than 2E-14
erg/cm2/s at 4 d. Reaction time: 4-6 days Observing Strategy: A first
X-ray observation (30 ks) is requested a few days after the burst
to detect an early jet-break. If no jet-break is present, a second
observation (70 ks) is requested a few weeks after the burst to detect
a possible late-time jet-break.