Abstract for Proposal 095179
Tracing Shock Development in a Nova
We propose 3x50ks observations of a new bright (V<7.5) nova likely to
be detected in gamma-rays. The observations will trace the development
of shocks within the nova ejecta, constrain the non-thermal particle acceleration and gamma-ray production mechanisms. We’ll put an upper
limit on the particle acceleration efficiency by comparing thermal X-ray and optical to GeV luminosity and search for predicted non-thermal X-rays.
Understanding nova shocks is relevant for other shock-powered transients: interacting supernovae, tidal disruption events, stellar mergers.
NuSTAR is the only instrument capable of detecting hard X-rays from novae simultaneously with the GeV emission.
The observations should be conducted now to take advantage of the simultaneous operations with Fermi, Swift and XMM.
Details on Observing Strategy and Trigger Criteria
Trigger criteria:
- A newly discovered nova reaching magnitude <7.5 in any of the standard optical photometry bands.
Required reaction time:
- The XMM-Newton exposure will be taken a few weeks after the NuSTAR observation
Observing strategy:
- NuSTAR observations will be conducted during the γ-ray peak (3 observations, the first about 48 hours after the trigger; the second observation is requested 2–3 days after the completion of the first observation; the third observation should be conducted 3–4 days after the second one).
A weekly Swift monitoring, starting a week after the latest NuSTAR epoch, will monitor the temperature, luminosity, and absorption of the shocked plasma. Swift data will determine the best timing for XMM spectroscopy.
The XMM observation should be conducted a few weeks after the NuSTAR trigger when the nova ejecta will become transparent to soft X-rays (known from Swift monitoring).