An Halpha-selected sample of cataclysmic variables -- I. Observations of newly discovered systems

Abstract

Strong selection effects are present in observational samples of cataclysmic variables (CVs), complicating comparisons to theoretical predictions. The selection criteria used to define most CV samples discriminate heavily against the discovery of short-period, intrinsically faint systems. The situation can be improved by selecting CVs for the presence of emission lines. For this reason, we have constructed a homogeneous sample of CVs selected on the basis of Halpha emission. We present discovery observations of the 14 CVs and 2 additional CV candidates found in this search. The orbital periods of 11 of the new CVs were measured; all are above 3 h. There are two eclipsing systems in the sample, and one in which we observed a quasi-periodic modulation on a \sim 1000 s time-scale. We also detect the secondary star in the spectrum of one system, and measure its spectral type. Several of the new CVs have the spectroscopic appearance of nova-like variables (NLs), and a few display what may be SW Sex star behaviour. In a companion paper, we discuss the implications of this new sample for CV evolution.

15 pages, 8 figures, accepted for publication in MNRAS

References in corpus (26)

• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• Color Transformations for the 2MASS Second Incremental Data Release
• The Indo-U.S. Library of Coude Feed Stellar Spectra
• A three-dimensional Galactic extinction model
• The Donor Stars of Cataclysmic Variables
• The Aao/Ukst Supercosmos H-alpha Survey (SHS)
• Cataclysmic Variables from SDSS II. The Second Year
• Cataclysmic Variables from SDSS I. The First Results
• Extinction with 2MASS: star counts and reddening toward the North America and the Pelican Nebulae
• Rapid Oscillations in Cataclysmic Variables
• On the late spectral types of cataclysmic variable secondaries
• SW Sextantis stars: the dominant population of CVs with orbital periods between 3-4 hours
• The census of cataclysmic variables in the ROSAT Bright Survey
• The mass of the white dwarf in the old nova BT Mon
• The space density of cataclysmic variables: constraints from the ROSAT North Ecliptic Pole Survey
• A Self-Occulting Accretion Disk in the SW Sex Star DW UMa
• The influence of selection effects on the observed cataclysmic variable population: modelling and application to the Palomar-Green sample
• Spectroscopic search for new SW Sextantis stars in the 3-4 hour orbital period range -- I
• Newly Discovered Cataclysmic Variables from the INT/WFC Photometric H alpha Survey of the Northern Galactic Plane
• Dwarf novae in the Hamburg Quasar Survey: Rarer than expected
• Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables -- V. Results from an extensive survey
• The Properties of Cataclysmic Variables In Photometric Halpha Surveys
• Cataclysmic variables from the Calan-Tololo-Survey -- I. Photometric periods
• Mapping quasi-periodic oscillations from the outbursting intermediate polar GK Persei
• An Halpha-selected sample of cataclysmic variables -- II. Implications for CV evolution
• Discovery of Two New Faint Cataclysmic Variables

Cited by in corpus (12)

• The Evolution of Cataclysmic Variables as Revealed by their Donor Stars
• Constraints on the space density of intermediate polars from the Swift-BAT survey
• The space density and X-ray luminosity function of non-magnetic cataclysmic variables
• The orbital period and system parameters of the recurrent nova T Pyx
• Photometric determination of the mass accretion rate of pre-main sequence stars. IV. Recent star formation in NGC 602
• TESS light curves of cataclysmic variables -- III -- More superhump systems among old novae and novalike variables
• Flux calibration of the AAO/UKST SuperCOSMOS H-alpha Survey
• A search for variable subdwarf B stars in TESS Full Frame Images -- I. Variable objects in the southern ecliptic hemisphere
• Hα photometry of low mass stars in 47 Tucanae: chromospheric activity and exotica
• On the absence of nova shells
• High speed photometry of faint cataclysmic variables - VI. Car2, V1040 Cen, Ha 075648, IL Nor (Nova Nor 1893), HS Pup (Nova Pup 1963), SDSS J2048-06, CSS 081419-005022 and CSS 112634-100210
• Tilted discs in six poorly studied cataclysmic variables