Abstract for Proposal 094084

XMM-NuSTAR observations of the most Extreme Mass Loss events from Massive Stars

Contrary to expectations from current stellar evolutionary models, recent observations uncovered the ejection of shells of material by massive stars in the years before the supernova (SN) explosion. The physical mechanism behind the impulsive mass ejection synchronized with the stellar core-collapse is unclear. Building on our recent success with SN2023ixf, here we propose a coordinated XMM-NuSTAR effort to map the evolution of the broad-band X-ray spectrum of 1 nearby (d< 50 Mpc) or X-ray bright (Fx>3 x 10^-13 erg/s/cm2) strongly interacting SN and enable progress. Our program has the immediate goal to characterize the medium around strongly interacting SNe, which originate from stellar progenitors with the most extreme mass loss before explosion.



Details on Observing Strategy and Trigger Criteria
Triggering Criteria: (i) SN at d<50 Mpc or with bright X-ray emission (Fx>3e-13 erg/s/cm2 as determined for example with Swift-XRT observations), (ii) that shows clear signatures of interaction in the optical spectra (i.e. narrow emission lines). Trigger Response Window: 2 weeks Follow-up Observation: +100 days from the first observation. Each of the two epochs will consist of 10 ks XMM + 50 ks NuSTAR