Radio detections of IR-selected runaway stellar bow shocks

Abstract

Massive stars moving at supersonic peculiar velocities through the interstellar medium (ISM) can create bow shocks, arc-like structures at the interface between the stellar wind and the ISM. Many such bow shocks have been detected and catalogued at IR wavelengths, but detections in other wavebands remain rare. Strikingly, while electrons are expected to be accelerated in the bow shock and their non-thermal emission may include synchrotron emission at low frequencies, only two massive runaway stellar bow shocks have to date been detected in the radio band. Here, we examine a sample of fifty IR-detected bow shocks from the E-BOSS catalogues in recently released radio images from the Rapid ASKAP Continuum Survey (RACS). We identify three confident and three likely counterparts, as well as three inconclusive candidates requiring confirmation via follow-up observations. These detections significantly increase the number of known radio massive stellar bow shocks and highlight the advantage of dedicated searches with current and next-generation radio telescopes. We investigate the underlying radio emission mechanism for these radio sources, finding a mix of free-free-dominated and synchrotron-dominated systems. We also discuss the non-detected targets by putting constraints on their emission properties and investigating their detectability with future observations. Finally, we propose several future avenues of research to advance the study and understanding of bow shocks at radio frequencies.

17 pages, 12 figures, 3 tables. Resubmitted to MNRAS after final round of very minor referee comments

References in corpus (15)

• Australian Square Kilometre Array Pathfinder: I. System Description
• The Rapid ASKAP Continuum Survey I: Design and First Results
• Measuring the cosmic ray acceleration efficiency of a supernova remnant
• The Australian Square Kilometre Array Pathfinder: System Architecture and Specifications of the Boolardy Engineering Test Array
• The Australian Square Kilometre Array Pathfinder: Performance of the Boolardy Engineering Test Array
• A comprehensive search for stellar bowshock nebulae in the Milky Way: a catalog of 709 mid-infrared selected candidates
• Interstellar Weather Vanes: GLIMPSE Mid-Infrared Stellar-Wind Bowshocks in M17 and RCW49
• E-BOSS: An Extensive stellar BOw Shock Survey. II. Catalogue second release
• Systematic search for high-energy gamma-ray emission from bow shocks of runaway stars
• X-ray study of bow shocks in runaway stars
• Modelling interstellar structures around Vela X-1
• The massive multiple system HD 64315
• MeerKAT discovery of radio emission from the Vela X-1 bow shock
• High-sensitivity radio study of the non-thermal stellar bow shock EB27
• The non-thermal emission from the colliding-wind binary Apep

Cited by in corpus (4)

• The Rapid ASKAP Continuum Survey IV: continuum imaging at 1367.5 MHz and the first data release of RACS-mid
• Thermal emission from bow shocks II: 3D magnetohydrodynamic models of Zeta Ophiuchi
• Probing the non-thermal physics of stellar bow shocks using radio observations
• Radio polarization from runaway star bowshocks-I. The general case