CHANG-ES VI: Probing Supernova Energy Deposition in Spiral Galaxies Through Multi-Wavelength Relationships


الملخص بالإنكليزية

How a galaxy regulates its SNe energy into different interstellar/circumgalactic medium components strongly affects galaxy evolution. Based on the JVLA D-configuration C- (6 GHz) and L-band (1.6 GHz) continuum observations, we perform statistical analysis comparing multi-wavelength properties of the CHANG-ES galaxies. The high-quality JVLA data and edge-on orientation enable us for the first time to include the halo into the energy budget for a complete radio-flux-limited sample. We find tight correlations of $L_{rm radio}$ with the mid-IR-based SFR. The normalization of our $I_{rm 1.6GHz}/{rm W~Hz^{-1}}-{rm SFR}$ relation is $sim$2-3 times of those obtained for face-on galaxies, probably a result of enhanced IR extinction at high inclination. We also find tight correlations between $L_{rm radio}$ and the SNe energy injection rate $dot{E}_{rm SN(Ia+CC)}$, indicating the energy loss via synchrotron radio continuum accounts for $sim0.1%$ of $dot{E}_{rm SN}$, comparable to the energy contained in CR electrons. The integrated C-to-L-band spectral index is $alphasim0.5-1.1$ for non-AGN galaxies, indicating a dominance by the diffuse synchrotron component. The low-scatter $L_{rm radio}-{rm SFR}$/$L_{rm radio}-dot{E}_{rm SN (Ia+CC)}$ relationships have super-linear logarithmic slopes at $sim2~sigma$ in L-band ($1.132pm0.067$/$1.175pm0.102$) while consistent with linear in C-band ($1.057pm0.075$/$1.100pm0.123$). The super-linearity could be naturally reproduced with non-calorimeter models for galaxy disks. Using Chandra halo X-ray measurements, we find sub-linear $L_{rm X}-L_{rm radio}$ relations. These results indicate that the observed radio halo of a starburst galaxy is close to electron calorimeter, and a galaxy with higher SFR tends to distribute an increased fraction of SNe energy into radio emission (than X-ray).

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