Investigating Galactic Supernova Remnant Candidates Using LOFAR

• Published in: The Astrophysical journal 2018-06, Vol.860 (2), p.133
• Main Authors: Driessen, Laura N., Dom ek, Vladimír, Vink, Jacco, Hessels, Jason W. T., Arias, Maria, Gelfand, Joseph D.
• Format: Article
• Language: English
• Subjects: Antenna arrays; Astrophysics; Emission lines; Flux density; Investigations; Ionization; ISM: supernova remnants; LOFAR; Morphology; Mosaics; Nebulae; Nonequilibrium ionization; Pulsar winds; Pulsars; radio continuum: ISM; Radio telescopes; regions; Stellar winds; Supernova; Supernova remnants; X ray analysis; X ray spectra; X-rays: ISM; XMM (spacecraft)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aac32e

We investigate six supernova remnant (SNR) candidates-G51.21+0.11, G52.37-0.70, G53.07+0.49, G53.41+0.03, G53.84-0.75, and the possible shell around G54.1+0.3-in the Galactic plane using newly acquired Low-Frequency Array High-band Antenna observations, as well as archival Westerbork Synthesis Radio Telescope and Very Large Array Galactic Plane Survey mosaics. We find that G52.37-0.70, G53.84-0.75, and the possible shell around pulsar wind nebula G54.1+0.3 are unlikely to be SNRs, while G53.07+0.49 remains a candidate SNR. G51.21+0.11 has a spectral index of = − 0.7 0.21, but lacks X-ray observations and as such requires further investigation to confirm its nature. We confirm one candidate, G53.41+0.03, as a new SNR because it has a shell-like morphology, a radio spectral index of = − 0.6 0.2 and it has the X-ray spectral characteristics of a 1000-8000 year old SNR. The X-ray analysis was performed using archival XMM-Newton observations, which show that G53.41+0.03 has strong emission lines and is best characterized by a nonequilibrium ionization model, consistent with an SNR interpretation. Deep Arecibo radio telescope searches for a pulsar associated with G53.41+0.03 resulted in no detection, but placed stringent upper limits on the flux density of such a source if it was beamed toward Earth.