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The NSFs Karl G. Jansky Very Large Array (VLA) is used to observe 122 magnetic cataclysmic variables (MCVs) during three observing semesters (13B, 15A, and 18A). We report radio detections of 33 stars with fluxes in the range 6--8031 uJy. Twenty-eight stars are new radio sources, increasing the number of radio detected MCVs to more that 40. A surprising result is that about three-quarters (24 of 33 stars) of the detections show highly circularly polarized radio emission of short duration, which is characteristic of electron cyclotron maser emission. We argue that this emission originates from the lower corona of the donor star, and not from a region between the two stars. Maser emission enables a more direct estimate of the mean coronal magnetic field of the donor star, which we estimate to be 1--4 kG assuming a magnetic filling factor of 50%. A two-sample Kolmogorov-Smirnov test supports the conclusion that the distribution function of radio detected MCVs with orbital periods between 1.5-5 hours is similar to that of all MCVs. This result implies that rapidly-rotating (Pspin < 10 days), fully convective stars can sustain strong magnetic dynamos. These results support the model of Taam & Spruit (1989) that the change in angular momentum loss across the fully convective boundary at Porb = ~3 hours is due to a change in the magnetic field structure of the donor star from a low-order to high-order multipolar field.
We use the complete, X-ray flux-limited ROSAT Bright Survey (RBS) to measure the space density of magnetic cataclysmic variables (mCVs). The survey provides complete optical identification of all sources with count rate >0.2/s over half the sky ($|b|
In a series of recent papers, it has been proposed that high field magnetic white dwarfs are the result of close binary interaction and merging. Population synthesis calculations have shown that the origin of isolated highly magnetic white dwarfs is
The origin of magnetic fields in isolated and binary white dwarfs has been investigated in a series of recent papers. One proposal is that magnetic fields are generated through an alpha-omega dynamo during common envelope evolution. Here we present p
We report on XMM-Newton and optical results for 6 cataclysmic variables that were selected from Sloan Digital Sky Survey spectra because they showed strong HeII emission lines, indicative of being candidates for containing white dwarfs with strong ma
Spectra of 38 candidate or known cataclysmic variables are presented. Most are candidate dwarf novae or systems containing possible highly magnetic white dwarfs, while a few (KR Aur, LS Peg, V380 Oph and V694 Mon) are previously known objects caught