Abstract for Proposal 096394

Accretion physics in the textbook polar EF Eri

The spectral components of polars - strongly magnetic CVs - were barely disentangled by previous X-ray missions. The physics of accretion in a strongly magnetic, non-relativistic environment is therefore still puzzling. Recently, the second brightest member of the class, EF Eri, awoke from an extended low state lasting 26 years. We propose a TOO-like XMM-Newton observation of EF Eri in its high state. We will investigate the physics of the hard X-ray emitting shock, the heated accretion pole cap, the atmosphere of the white dwarf, the absorption in the shock and in the flow, the lines in the accretion flow and the reflection from the white dwarf by phase-resolved spectroscopy and high-speed OM-photometry.

Details on Observing Strategy and Trigger Criteria
The source shall be in a stable high state. Stable means for at least 10 days. A high state is indicated if the optical brightness lies between 13 and 15 mag (orbital variability). The AAVSO observers will provide dense photometric coverage. Reaction time requested is 5 days. Prime instrument is EPIC-pn, which will be used in small window mode with the thick filter. Total time on target is 30 ksec.