The multi-phase ISM in the nearby composite AGN-SB galaxy NGC 4945: large (parsecs) scale mechanical heating
Abstract
We carry out a comprehensive study of the nearby composite AGN-SB galaxy, NGC 4945, using spectroscopic and photometric data from the Herschel satellite. In particular, we characterize the thermal structure in this galaxy by a multi-transitions analysis of the spatial distribution of the 12CO emission at different spatial scales. We also establish the dominant heating mechanism at work in the inner region of this object at smaller spatial scales (200 pc). Indeed, the thermal structure derived from the 12CO multi-transition analysis suggests that mechanical heating, like shocks or turbulence, dominates the heating of the ISM in the nucleus of NGC 4945 located beyond 100 pc (>5") from the center of the galaxy. Shocks and/or turbulence are likely produced by the barred potential and the outflow, observed in X-rays. This result is confirmed by the mechanical heating models, which suggest the existence of PDRs but mainly dominated by mechanical heating (i.e., feedback from SNe) in the inner regions of NGC 4945.
- Publication:
-
XIV.0 Scientific Meeting (virtual) of the Spanish Astronomical Society
- Pub Date:
- July 2020
- Bibcode:
- 2020sea..confE..10B