Cataclysmic Variables Are Radio Sources

cataclysmic_variables.jpgRadio emission from non-magnetic cataclysmic variables (CVs, accreting white dwarfs) could allow detailed studies of outflows and possibly accretion flows in these nearby, numerous and non-relativistic compact accretors. Until recently, however, very few CVs have been detected in the radio. Coppejans et al. have conducted a VLA pilot survey of four close and optically bright nova-like CVs at 6 GHz, detecting three, and thereby doubling the number of radio detections of these systems. These observations clearly show that the sensitivity of previous surveys was typically too low to detect these objects and that non-magnetic CVs can indeed be significant radio emitters. The three detected sources show a range of properties, including flaring and variability on both short (∼200 s) and longer-term (days) time-scales, as well as circular polarization levels of up to 100%. The spectral indices range from steep to inverted. This range of properties suggests that more than one emission process can be responsible for the radio emission in non-magnetic CVs. In this sample, the athors find that individual systems are consistent with optically thick synchrotron emission, gyrosynchrotron emission or cyclotron maser emission.

View Paper: Novalike Cataclysmic Variables are Signicant Radio Emitters, Deanne L. Coppejans (Radboud), Elmar G. Körding (Radboud), James C. A. Miller-Jones (Curtin), Michael P. Rupen (NRC-Herzberg), Christian Knigge (Southampton), Gregory R. Sivakoff (Alberta), and Paul J. Groot (Radboud), 2015 MNRAS, 451, 3801 (published online 29 June 2015).

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