Two Radio Supernova Remnants Discovered in the Outer Galaxy

Abstract

We report on the discovery of two supernova remnants (SNRs) designated G152.4-2.1 and G190.9-2.2, using Canadian Galactic Plane Survey data. The aims of this paper are, first, to present evidence that favours the classification of both sources as SNRs, and, second, to describe basic parameters (integrated flux density, spectrum, and polarization) as well as properties (morphology, line-of-sight velocity, distance and physical size) to facilitate and motivate future observations. Spectral and polarization parameters are derived from multiwavelength data from existing radio surveys carried out at wavelengths between 6 and 92cm. In particular for the source G152.4-2.1 we also use new observations at 11cm done with the Effelsberg 100m telescope. The interstellar medium around the discovered sources is analyzed using 1-arcminute line data from neutral hydrogen (HI) and 45-arcsecond 12CO(J=1-0). G152.4-2.1 is a barrel shaped SNR with two opposed radio-bright polarized flanks on the North and South. The remnant, which is elongated along the Galactic plane is evolving in a more-or-less uniform medium. G190.9-2.2 is also a shell-type remnant with East and West halves elongated perpendicular to the plane, and is evolving within a low-density region bounded by dense neutral hydrogen in the North and South, and molecular (12CO) clouds in the East and West. The integrated radio continuum spectral indices are -0.65+/-0.05 and -0.66+/-0.05 for G152.4-2.1 and G190.9-2.2 respectively. Both SNRs are approximately 1 kpc distant, with G152.4-2.1 being larger (32x30 pc in diameter) than G190.9-2.2 (18x16 pc). These two remnants are the lowest surface brightness SNRs yet catalogued at 5x10^-23 W m^-2 Hz^-1 sr^-1.

Published in Astronomy & Astrophysics, January 2013 Vol. 549, Article No. A107, 9 pages

References in corpus (5)

• Discovery of 35 New Supernova Remnants in the Inner Galaxy
• A Sino-German lambda6 cm polarization survey of the Galactic plane I. Survey strategy and results for the first survey region
• A sharper view of the outer Galaxy at 1420 and 408 MHz from the Canadian Galactic Plane Survey II: The catalogue of extended radio sources
• Discovery of A New Faint Radio SNR G108.2-0.6
• A "Missing" Supernova Remnant revealed by the 21-cm Line of Atomic Hydrogen

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• The Search for Faint Radio Supernova Remnants in the Outer Galaxy: Five New Discoveries
• Discovery of a new supernova remnant G150.3+4.5
• Peering into the Milky Way by FAST: IV. Identification of two new Galactic supernova remnants G203.1+6.6 and G206.7+5.9
• A High Resolution Survey of the Galactic Plane at 408 MHz
• XMM-Newton and Canadian Galactic Plane Survey Observations of the Supernova Remnant G107.5-1.5
• Radio properties of the optically identified supernova remnant G107.0+9.0