The analysis of the possible thermal emission at radio frequencies from an evolved supernova remnant HB 3 (G132.7+1.3): Revisited

Abstract

It has recently been reported that some of the flux density values for an evolved supernova remnant (SNR) HB 3 (G132.7+1.3) are not accurate enough. In this work we therefore revised the analysis of the possible thermal emission at radio frequencies from this SNR using the recently published, corrected flux density values. A model including the sum of non-thermal (purely synchrotron) and thermal (bremsstrahlung) components is applied to fit the integrated radio spectrum of this SNR. The contribution of thermal component to the total volume emissivity at 1 GHz is estimated to be ≈ 37%. The ambient density is also estimated to be n ≈ 9 cm-3 for T = 104 K. Again we obtained a relatively significant presence of thermal emission at radio frequencies from the SNR, which can support interaction between SNR HB 3 and adjacent molecular cloud associated with the H II region W3. Our model estimates for thermal component contribution to total volume emissivity at 1 GHz and ambient density are similar to those obtained earlier (≈ 40 %, ≈ 10 cm-3). It is thus obvious that the corrected flux density values do not affect the basic conclusions.