Detection of X-ray Emission from a Bright Long-Period Radio Transient

Abstract

Recently, a class of long-period radio transients (LPTs) has been discovered, exhibiting emission on timescales thousands of times longer than radio pulsars. Several models had been proposed implicating either a strong magnetic field neutron star, isolated white dwarf pulsar, or a white dwarf binary system with a low-mass companion. While several models for LPTs also predict X-ray emission, no LPTs have been detected in X-rays despite extensive searches. Here we report the discovery of an extremely bright LPT (10-20 Jy in radio), ASKAP J1832-0911, which has coincident radio and X-ray emission, both with a 44.2-minute period. The X-ray and radio luminosities are correlated and vary by several orders of magnitude. These properties are unique amongst known Galactic objects and require a new explanation. We consider a $\gtrsim 0.5$ Myr old magnetar with a $\gtrsim 10^{13}$ G crustal field, or an extremely magnetised white dwarf in a binary system with a dwarf companion, to be plausible explanations for ASKAP J1832-0911, although both explanations pose significant challenges to formation and emission theories. The X-ray detection also establishes a new class of hour-scale periodic X-ray transients of luminosity $\sim 10^{33}$ erg/s associated with exceptionally bright coherent radio emission.

52 pages, 17 figures, 3 tables

References in corpus (30)

• HI4PI: A full-sky HI survey based on EBHIS and GASS
• TEMPO2, a new pulsar timing package. I: Overview
• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• Transient pulsed radio emission from a magnetar
• Australian Square Kilometre Array Pathfinder: I. System Description
• The Rapid ASKAP Continuum Survey I: Design and First Results
• A radio pulsing white dwarf binary star
• The Rapid ASKAP Continuum Survey Paper II: First Stokes I Source Catalogue Data Release
• PINT: A Modern Software Package for Pulsar Timing
• The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime
• Discovery of a radio emitting neutron star with an ultra-long spin period of 76 seconds
• A radio transient with unusually slow periodic emission
• The Einstein Probe Mission
• Current challenges in the physics of white dwarf stars
• A long-period radio transient active for three decades
• An emission state switching radio transient with a 54 minute period
• Evidence for an abundant old population of Galactic ultra long period magnetars and implications for fast radio bursts
• Magneto-thermal evolution of neutron stars with coupled Ohmic, Hall and ambipolar effects via accurate finite-volume simulations
• The Thousand-Pulsar-Array programme on MeerKAT IV: Polarisation properties of young, energetic pulsars
• Sporadic radio pulses from a white dwarf binary at the orbital period
• GLEAM-X J16279.5-523504.3 as a White Dwarf Pulsar
• Constraining the nature of the 18-min periodic radio transient GLEAM-X J162759.5-523504.3 via multi-wavelength observations and magneto-thermal simulations
• 3D code for MAgneto-Thermal evolution in Isolated Neutron Stars, MATINS: The Magnetic Field Formalism
• X-ray properties of the white dwarf pulsar eRASSU J191213.9-441044
• The CRAFT Coherent (CRACO) upgrade I: System Description and Results of the 110-ms Radio Transient Pilot Survey
• A Measurement of Source Noise at Low Frequency: Implications for Modern Interferometers
• The ASKAP Variables and Slow Transients (VAST) Pilot Survey
• NIR spectral classification of the companion in the gamma-ray binary HESS J1832-093 as an O6 V star
• Constraints on the dense matter equation of state from young and cold isolated neutron stars

Cited by in corpus (7)

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• Modeling isolated magnetar spin-down evolution and implications for long-period radio transients
• A Falsifiable Timing Test for the Double-White-Dwarf Model of Long-Period Transients
• The X-ray emission of the long-period transient and accreting cataclysmic variable ASKAP J174508.9-505149