Cataclysmic Variables from Sloan Digital Sky Survey. IV. The Fourth Year (2003)

Abstract

This paper continues the series presenting cataclysmic variables identified during the fourth year (2003) of the Sloan Digital Sky Survey. We describe 44 close binary systems, of which 12 are the previously known systems EN Cet, EG Cnc, V844 Her, GG Leo, Leo 7, CY UMa, DV UMa, EK UMa, EV UMa, UMa 8, EUVE J0854+390, and RX J0859.1+0537 and 32 are new cataclysmic variables. As in the previous papers, the positions, colors, and spectra of all 44 systems are shown, along with follow-up spectroscopic, photometric, and/or polarimetric observations of 15 of the new systems. The new objects include one eclipsing system, eight with prominent He ii emission (of which two are confirmed new polars), and 12 systems showing features of the underlying stars. Our spectropolarimetry also confirms EUVE J0854+390 as a polar.

Orbital periods of cataclysmic variables identified by the SDSS

“…It is not clear why eclipses were not detected by Szkody et al (2005), although it must be remembered that the telescope available to these authors was much smaller (1.0 m versus 3.6 m). Dr. A. Henden (private communication) has kindly supplied the data from Szkody et al for a closer inspection.…”

“…SDSS J0924 is another new discovery from the SDSS survey, identified by Szkody et al (2005) due to a spectrum which shows strong and narrow Balmer emission and hints of the secondary star towards the red end. The presence of strong He ii is indicative of a magnetic system, but polarimetric observations revealed no polarisation.…”

“…We have a short sequence of spectroscopic observations from 2008 February which indicate a period of about 80 min and will be presented in a later paper. 6 See http://cbastro.org/ 7 vsnet-alert number 8239 8 vsnet-gcvs number 614 9 vsnet-alert number 11069 10 vsnet-outburst number 10022 11 vsnet-alert number 11075 SDSS J0906 was found to be a CV by Szkody et al (2005) from an SDSS spectrum which shows moderately weak Balmer line emission. Twelve outbursts, of amplitude roughly 3 mag, have been seen by the CSS (Drake et al 2009), which makes it a frequently-outbursting system.…”

1000 cataclysmic variables from the Catalina Real-time Transient Survey

“…Szkody et al (2002Szkody et al ( , 2003Szkody et al ( , 2004Szkody et al ( , 2005Szkody et al ( , 2006Szkody et al ( , 2007Szkody et al ( , 2009Szkody et al ( , 2011) produced a catalogue of 285 CVs identified in this way. The Quasar Survey is estimated to be 95 per cent complete down to i < 19.1 (Vanden Berk et al 2005;Richards et al 2006).…”

Orbital periods of cataclysmic variables identified by the SDSS

“…SDSS J0039 was discovered to be a CV by Szkody et al (2005) on the basis of an SDSS spectrum which shows Balmer and He I emission lines. Very broad absorption is visible around the higher-order Balmer lines, indicating that the WD emits a large fraction of the overall light of the system.…”