Radio observations and spectrum of the SNR G127.1+0.5 and its central source 0125+628

¹ Department of Physics & Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada e-mail: wtian@ucalgary.ca; leahy@iras.ucalgary.ca
² National Astronomical Observatories, CAS, Beijing 100012, PR China

Received: 7 December 2005
Accepted: 23 January 2006

Abstract

We present new images of the Supernova Remnant (SNR) G127.1+0.5 (R5), based on the 408 MHz and 1420 MHz continuum emission and the HI-line emission data of the Canadian Galactic Plane Survey (CGPS). The radio spectrum of the central compact source (0125+628) is analyzed in the range 178 MHz–8.7 GHz, indicating a flat spectrum with synchrotron self-absorption below 800 MHz. The SNR's flux density at 408 MHz is 17.1 ± 1.7 Jy and at 1420 MHz is 10.0 ± 0.8 Jy, corrected for flux densities from compact sources within the SNR. The SNR's integrated flux density based spectral index (  ν) is 0.43 ± 0.10. The respective T-T plot spectral index (derived from the relative size of brightness temperature variations between two frequencies, see text for details) is 0.46 ± 0.01. There is no evidence at 1σ for spatial variations in spectral index within G127.1+0.5. In particular, we compared the northern shell, southern shell and central diffuse region. HI observations show structures associated with the SNR in the radial velocity range of -12 to -16 km s^-1, suggesting G127.1+0.5's distance is 1.15 kpc. The estimated Sedov age is 2–3  10⁴ yr.