Exploring the supernova remnant G308.4–1.4

Max Planck Institute for extraterrestrial Physics, PO Box 1312, Giessenbachstr., 85741 Garching, Germany
e-mail: tprinz@mpe.mpg.de

Received: 21 February 2012
Accepted: 22 May 2012

Abstract

Aims. We present a detailed X-ray and radio wavelength study of G308.4–1.4, a candidate supernova remnant (SNR) in the ROSAT All Sky Survey and the MOST supernova remnant catalog to identify it as a SNR.

Methods. The SNR candidate and its central sources were studied using observations from the Chandra X-ray Observatory, Swift, the Australian Telescope Compact Array (ATCA) at 1.4 and 2.5 GHz and WISE infrared observation at 24 μm.

Results. We conclude that G308.4–1.4 is indeed a supernova remnant because its morphology matches at X-ray, radio- and infrared wavelengths, its spectral energy distribution in the X-ray band, and its emission characteristics in the radio band. G308.4–1.4 is a shell-type SNR. X-ray, radio- and infrared emission is seen only in the eastern part of the remnant. The X-ray emission can best be described by an absorbed non-equilibrium collisional plasma with a hydrogen density of n_H = (1.02 ± 0.04) × 10²² cm^-2, a plasma temperature of 6.3_-0.7^+1.2 million Kelvin, and an under-abundance of iron, neon and magnesium, as well as an overabundance in sulfur with respect to the solar values. The SNR has a spectral index in the radio band of α = −0.7 ± 0.2. A detailed analysis revealed that the remnant is at a distance of 6 to 12 kpc and the progenitor star exploded ~ 5000 to 7500 years ago. Two faint X-ray point sources located near to the remnant’s geometrical center are detected. Both sources have no counterpart at other wavelengths, leaving them as candidates for the compact remnant of the supernova explosion.