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Abstract Recent observations of long period radio transients, such as GLEAM-X J0704–37 and ILT J1101+5521, have revealed a previously unrecognized population of Galactic radio transient sources associated with white dwarf (WD)–M dwarf (MD) binaries. It is an open question how to produce coherent radio emission in these systems, though a model driven by binary interaction seems likely given the nature and correlation of the emission with the binaries’ orbital period. Using kinetic plasma simulations, we demonstrate that the relativistic electron cyclotron maser instability (ECMI) is a viable mechanism for generating radio pulses in WD–MD systems, akin to planetary radio emission, such as that from the Jupiter–Io system. We quantify the relativistic ECMI in the nonlinear regime under conditions relevant for WD radio emission for the first time. Our simulations demonstrate that the ECMI can intrinsically produce partially linearly polarized emission relevant to explaining the observed emission spectra of two Galactic sources, though the precise details will depend on the plasma composition. Our work paves the way for a systematic and fully nonlinear computational modeling of radio emission from interacting WD sources.
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This content will become publicly available on May 18, 2027
A Sample of Short-lived Galactic Radio Transients from ASKAP VAST
Abstract Galactic radio transients (GRTs) are mysterious short-lived (∼days to months) radio transients that are quiet at all other wavelengths. Until now, roughly half a dozen such sources have been reported, predominantly towards the Galactic center. However, no unifying properties have been identified among these, leaving their nature, emission mechanism, and even classification poorly understood. Due to the lack of periodic and uniform radio observations over wide areas of the Galactic plane until now, the sample size of such transients remained limited. Here, we use radio observations from the Australian SKA Pathfinder’s Variables and Slow Transients survey to discover six new radio transients along the Galactic plane that resemble GRTs. Detailed investigation of archival data suggests that these sources may be divided into two classes: sources that exhibit sporadic, pulse-like (minutes) radio emission, and sources that exhibit long-term (weeks) flaring-type radio emission. For the short-time variable sources, we draw similarities between optically bright long-period radio transients and our sample to propose wide-orbit (∼days) white dwarf binaries as underlying sources. For sources that show long-term outbursts, we draw comparisons between dust-obscured outbursts from WD binaries and our sample. These results could imply that the ongoing wide-field radio surveys are uncovering radio emission from subpopulations of WD binaries that were previously unexplored.
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- PAR ID:
- 10697967
- Publisher / Repository:
- AAS
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 1003
- Issue:
- 1
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 91
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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