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Evidence for an eclipse in SWIFT J052522.48+241331.8

ATel #2093; Gavin Ramsay (Armagh Observatory) on behalf of the RATS collaboration
on 22 Jun 2009; 18:25 UT
Credential Certification: Gavin Ramsay (gar@arm.ac.uk)

Subjects: Optical, X-ray, Request for Observations, Binary, Cataclysmic Variable, Variables

On 6th Oct 2008 we obtained 4 optical spectra of SWIFT J052522.48+241331.8 (cf Page, Tueller & Beardmore 2007, ATEL #1279 and Torres et al 2007, ATEL #1286) using ISIS on the 4.2m William Herschel Telescope in La Palma. In 3 of the spectra (each had an exposure of 240 sec), emission lines were detected, the most prominent being Halpha (consistent with observations reported by Torres et al). However, in one spectrum, the source was much fainter and no prominent emission lines were seen. Torres et al identify SWIFT J052522.48+241331.8 as a cataclysmic variable. Further, they suggest it is either a magnetic or a high accretion rate system. Our WHT observations suggest it is an eclipsing cataclysmic variable. If the emission seen during the eclipse largely originates from the secondary (mass donating) star then its spectral type is likely to be earlier than ~M2. As well as the SWIFT source being consistent with the location of a ROSAT source, (1RX J052523.2+241331), it is also appears consistent with the position of a bright (~2.4 ct/s) X-ray source (XMMSL1 J052522.5+241341) reported in the XMM-Newton slew survey catalogue (Saxton et al 2008, A&A, 480, 611). Observations are encouraged to confirm the presence of the eclipse and to determine the orbital period.