GALEX and Optical Light Curves of EF Eridanus During a Low State: the Puzzling Source of UV Light

Abstract

Low state optical photometry of EF Eri during an extended low accretion state combined with GALEX near and far UV time-resolved photometry reveals a source of UV flux that is much larger than the underlying 9500K white dwarf, and that is highly modulated on the orbital period. The near UV and optical light curves can be modeled with a 20,000K spot but no spot model can explain both the large amplitude FUV variations and the SED. The limitations of limb darkening, cyclotron and magnetic white dwarf models in explaining the observations are discussed.

arXiv comment10 pages, 4 figures to be published in ApJ Letters

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Cited by in corpus (12)

• Cataclysmic Variable Primary Effective Temperatures: Constraints on Binary Angular Momentum Loss
• Zeeman tomography of magnetic white dwarfs IV. The complex field structure of the polars EF Eri, BL Hyi, and CP Tuc
• The nature of the close magnetic white dwarf + probable brown dwarf binary SDSS J121209.31+013627.7
• Mass Determination and Detection of the Onset of Chromospheric Activity for the Sub-Stellar Object in EF Eridani
• Cyclotron modeling phase-resolved infrared spectroscopy of polars I: EF Eridani
• XMM-Newton observations of EF Eridani: the textbook example of low-accretion rate polars
• The Mid-Infrared Spectrum of the Short Orbital Period Polar EF Eridani from the Spitzer Space Telescope
• X-Shooting EF Eridani: further evidence for a massive white dwarf and a sub-stellar secondary
• GALEX, Optical and IR Light Curves of MQ Dra: UV Excesses at Low Accretion Rates
• Analyzing the Low State of EF Eridani with Hubble Space Telescope Ultraviolet Spectra
• Multiwavelength observations of V479 Andromedae: a close compact binary with an identity crisis
• GALEX and Optical Light Curves of WX LMi, SDSSJ103100.5+202832.2 and SDSSJ121209.31+013627.7