New supernova remnant candidates in the LOFAR Two Metre Sky Survey

Abstract

In spite of their key role in galaxy evolution and several decades of observational efforts, the census of supernova remnants (SNRs) in our Galaxy remains incomplete. Theoretical predictions based on the local supernova rate estimate the expected number of SNRs in the Galaxy to be $\gtrsim$ 1000. By contrast, the number of detected SNRs amounts to about 300. High-resolution, wide-area radio surveys at low frequencies are ideal tools with which to find missing SNRs, given the prominence of these sources at low radio frequencies. We aim to find missing SNRs using proprietary data from the LOFAR Two-Metre Sky Survey (LoTSS) at 144~MHz. We used LoTSS total intensity maps of two Galactic regions, one with $39^{\mathrm{o}}<l<66^{\mathrm{o}}$ and $|b|<2.5^{\mathrm{o}}$, and the other with $145^{\mathrm{o}}<l<150^{\mathrm{o}}$ and $|b|<3^{\mathrm{o}}$, in addition to mid-infrared (MIR) data from the Wide-field Infrared Survey Explorer (WISE) all-sky survey to search for SNR candidates. We report the discovery of 14 new SNR candidates selected on the basis of their morphology at 144 MHz and a lack of MIR emission. We also follow up on 24 previously reported SNR candidates, inferring their spectral index between the LoTSS frequency (144 MHz) and the frequency at which they were reported. The high resolution and sensitivity of LoTSS observations has resulted in the detection of 14 new SNR candidates. In order to unambiguously confirm the SNR nature of these candidates, follow-up X-ray observations are required with facilities such as eROSITA.

Accepted in A&A

References in corpus (23)

• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• The LOFAR Two-metre Sky Survey -- V. Second data release
• The VLA Galactic Plane Survey
• The SRG X-ray orbital observatory, its telescopes and first scientific results
• Australian Square Kilometre Array Pathfinder: I. System Description
• The Very Large Array Low-frequency Sky Survey Redux (VLSSr)
• Global cosmic-ray related luminosity and energy budget of the Milky Way
• Discovery of 35 New Supernova Remnants in the Inner Galaxy
• LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North Galactic Pole field
• Galactic Supernova Remnant Candidates Discovered by THOR
• The Planck clusters in the LOFAR sky. I. LoTSS-DR2: new detections and sample overview
• A global view on star formation: The GLOSTAR Galactic Plane Survey. I. Overview and first results for the Galactic longitude range 28° < l < 36°
• Distances, Radial Distribution and Total Number of Galactic Supernova Remnants
• Supernova feedback and the energy deposition in molecular clouds
• A global view on star formation: The GLOSTAR Galactic plane survey. II. Supernova Remnants in the first quadrant of the Milky Way
• Star formation triggered by SN explosions: an application to the stellar association of $\beta$ Pictoris
• Candidate radio supernova remnants observed by the GLEAM survey over $345^{\circ }<l<60^{\circ }$ and $180^{\circ }<l<240^{\circ }$
• A Catalogue of Radio Supernova Remnants and Candidate Supernova Remnants in the EMU/POSSUM Galactic Pilot Field
• New candidate radio supernova remnants detected in the GLEAM survey over $345^{\circ }<l<60^{\circ }$, $180^{\circ }<l<240^{\circ }$
• Study of 72 pulsars discovered in the PALFA survey: Timing analysis, glitch activity, emission variability, and a pulsar in an eccentric binary
• Diffuse radio emission from non-Planck galaxy clusters in the LoTSS-DR2 fields
• Search for and Identification of Young Compact Galactic Supernova Remnants Using THOR

Cited by in corpus (1)

• NuSTAR and XMM-Newton Observations of PSR J1930+1852 and Its Pulsar Wind Nebula