High-speed photometry of faint cataclysmic variables - VII. Targets selected from the Sloan Digital Sky Survey and the Catalina Real-time Transient Survey

Abstract

We present high‐speed photometric observations of 20 faint cataclysmic variables (CVs) selected from the Sloan Digital Sky Survey (SDSS) and Catalina catalogues. Measurements are given of 15 new directly measured orbital periods, including four eclipsing dwarf novae (SDSS 0904+03, CSS 0826−00, CSS 1404−10 and CSS 1626−12), two new polars (CSS 0810+00 and CSS 1503−22) and two dwarf novae with superhumps in quiescence (CSS 0322+02 and CSS 0826−00). Whilst most of the dwarf novae presented here have periods below 2 h, SDSS 0805+07 and SSS 0617−36 have relatively long orbital periods of 5.489 and 3.440 h, respectively. The double‐humped orbital modulations observed in SSS 0221−26, CSS 0345−01, CSS 1300+11 and CSS 1443−17 are typical of low‐mass transfer rate dwarf novae. The white dwarf primary of SDSS 0919+08 is confirmed to have non‐radial oscillations, and quasi‐periodic oscillations were observed in the short‐period dwarf nova CSS 1028−08 during outburst. We further report the detection of a new nova‐like variable (SDSS 1519+06). The frequency distribution of orbital periods of CVs in the Catalina Real‐time Transient Survey (CRTS) has a high peak near ∼80 min orbital period, independently confirming that found by Gänsicke et al. from SDSS sources. We also observe a marked correlation between the median in the orbital period distribution and the outburst class, in the sense that dwarf novae with a single observed outburst (over the 5‐year baseline of the CRTS coverage) occur predominantly at shortest orbital period.

1000 cataclysmic variables from the Catalina Real-time Transient Survey

“…Three of these have already been confirmed as eclipsers: CRTS J043829.1+004016 was found to be a deeply eclipsing CV (∼1 mag) by Coppejans et al (2014), who measured an orbital period of 94.306 min. The same group also reported CRTS J082654.7−000733 and CRTS J140454.0−102702 to be eclipsing CVs, with orbital periods of 85.794 and 86.05 min, respectively (Woudt et al 2012). Consistent with the short orbital periods, our spectra of these two CVs show clear absorption from the white dwarf in the Balmer lines (see Section 3.2), and in the case of CRTS J140454.0−102702, the spectrum is strongly dominated by the white dwarf emission.…”

“…Only 174 (17 per cent) of these CVs were known prior to the start of CRTS, 869 are new discoveries. The results from various follow-up programmes (Section 3 of this paper; Kato et al 2009Kato et al , 2010Kato et al , 2012Kato et al , 2013Thorstensen & Skinner 2012;Woudt et al 2012;Coppejans et al 2014) show that the identification process is highly accurate. Between 97 and 100 per cent of individual samples of CV candidates which were followed up were confirmed as CVs.…”

“…The spectrum of this system also displays broad Ca II emission, likely from the accretion disc. Woudt et al (2012) found a strong double-humped modulation in the quiescent light curve of CRTS J130030.3+115101 and measured an orbital period of 90.24 min. They also report CRTS J140454.0−102702 to be an eclipsing CV with a period of 86.05 min.…”

“…They also report CRTS J140454.0−102702 to be an eclipsing CV with a period of 86.05 min. CRTS J132103.2+015329, also known as HV Vir, has an orbital period of 82.18 min (Patterson et al 2003;Woudt et al 2012). …”

“…Thorstensen & Skinner 2012;Woudt et al 2012;Coppejans et al 2014). The transient selection criteria, CV identification process, spatial distribution and photometric properties of the overall sample were presented by Drake et al (2014).…”