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Using JVLA data obtained from high-resolution observations at 5.5 GHz at multiple epochs in 2014 and 2019, we have detected a population of radio variables and transients in the radio bright zone at the Galactic center. With observations…

High Energy Astrophysical Phenomena · Physics 2021-01-06 Jun-Hui Zhao , Mark R. Morris , W. M. Goss

M dwarfs are known to flare on timescales from minutes to hours, with flux increases of several magnitudes in the blue/near-UV. These frequent, powerful events, which are caused by magnetic reconnection, will have a strong observational…

Solar and Stellar Astrophysics · Physics 2015-03-17 Eric J. Hilton , Suzanne L. Hawley , Adam F. Kowalski , Jon Holtzman

Radio 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. Up to now, however,…

AM CVn systems are ultra-compact, helium-rich, accreting binaries with degenerate or semi-degenerate donors. We report the discovery of five new eclipsing AM CVn systems with orbital periods of 61.5, 55.5, 53.3, 37.4, and 35.4 minutes.…

Double Periodic Variables (DPV) are among the new enigmas of semi-detached eclipsing binaries. These are intermediate-mass binaries characterized by a long photometric period lasting on average 33 times the orbital period. We present a…

Solar and Stellar Astrophysics · Physics 2021-03-08 J. A. Rosales , R. E. Mennickent , G. Djurašević , I. Araya , M. Curé

Active M-dwarfs are known to produce bursty radio emission, and multi-wavelength studies have shown that Solar-like magnetic activity occurs in these stars. However, coherent bursts from active M-dwarfs have often been difficult to…

The population of radio-loud stars has to date been studied primarily through either targeted observations of a small number of highly active stars or widefield, single-epoch surveys that cannot easily distinguish stellar emission from…

Solar and Stellar Astrophysics · Physics 2023-12-19 Joshua Pritchard , Tara Murphy , George Heald , Michael S. Wheatland , David L. Kaplan , Emil Lenc , Andrew O'Brien , Ziteng Wang

We present results of our analysis of up to 15 years of photometric data from eight AM CVn systems with orbital periods between 22.5 and 26.8 min. Our data has been collected from the GOTO, ZTF, Pan-STARRS, ASAS-SN and Catalina all-sky…

AR Scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. Here we aim to investigate the multi-frequency radio emission of AR Sco in detail, in order to constrain its origin and…

Solar and Stellar Astrophysics · Physics 2018-03-28 E. R. Stanway , T. R. Marsh , P. Chote , B. T. Gaensicke , D. Steeghs , P. J. Wheatley

One of the most important problems in the context of cataclysmic variables (CVs) is the lack of observations of systems with periods between 2 and 3.12 hours, known as the period gap. The orbital evolution of CVs with periods shorter than…

Solar and Stellar Astrophysics · Physics 2018-11-28 C. Garraffo , J. J. Drake , J. D. Alvarado-Gomez , S. P. Moschou , O. Cohen

Recent observations of long period radio transients, such as GLEAM-X J0704-37 and ILTJ1101 + 5521, have revealed a previously unrecognized population of galactic radio transient sources associated with white dwarf - M dwarf binaries. It is…

High Energy Astrophysical Phenomena · Physics 2025-09-12 Yici Zhong , Elias R. Most

Short time-scale radio variations of compact extragalactic radio quasars and blazars known as IntraDay Variability (IDV) can be explained in at least some sources as a propagation effect; the variations are interpreted as scintillation of…

Coherent radio emission with properties similar to planetary auroral signals has been reported from GJ 1151, a quiescent, slow-rotating mid-M star, by the LOFAR Two-metre (120-170 MHz) Sky Survey (LoTSS). The observed {LOFAR} emission is…

The variable star AR Sco was recently discovered to pulse in brightness every 1.97 min from ultraviolet wavelengths into the radio regime. The system is composed of a cool, low-mass star in a tight, 3.55 hr orbit with a more massive white…

High Energy Astrophysical Phenomena · Physics 2017-01-26 D. A. H. Buckley , P. J. Meintjes , S. B. Potter , T. R. Marsh , B. T Gänsicke

We present the serendipitous discovery of 8 distant ($>$ 50 pc) late M dwarfs with plausible associated radio emission at 144 MHz. The M dwarf nature of our sources has been confirmed with optical spectroscopy performed using HET/LRS2 and…

We report our discovery of an extremely rare, low mass, quadruple-lined spectroscopic binary BD-22 5866 (=NLTT 53279, integrated spectral type = M0 V), found during an ongoing search for the youngest M dwarfs in the solar neighborhood. From…

We present the discovery and subarcsecond localization of a new Fast Radio Burst with the Karl G. Jansky Very Large Array and realfast search system. The FRB was discovered on 2019 June 14 with a dispersion measure of 959 pc/cm3. This is…

The accelerated electrons during solar flares produce radio bursts and nonthermal X-ray signatures. The quasi-periodic pulsations (QPPs) and fine structures in spatial-spectral-temporal space in radio bursts depend on the emission mechanism…

Solar and Stellar Astrophysics · Physics 2024-05-08 Rohit Sharma , Marina Battaglia , Sijie Yu , Bin Chen , Yingjie Luo , Sam Krucker

The connection between accretion and jet production in accreting white dwarf binary systems, especially dwarf novae, is not well understood. Radio wavelengths provide key insights into the mechanisms responsible for accelerating electrons,…

We report on the discovery of one of the most extreme cases of high-frequency radio variability ever measured in active galactic nuclei (AGN), observed on timescales of days and exhibiting variability amplitudes of three to four orders of…