High-Temperature Chemistry in External Galaxies

TL;DR

This paper reviews chemical models of heating mechanisms in the interstellar medium of external galaxies and presents recent ALMA observations revealing chemical compositions influenced by star formation and black hole activity.

Contribution

It provides a comprehensive overview of chemical models related to various heating mechanisms and shares new ALMA observational results in specific galaxies.

Findings

Detection of molecular species in external galaxies with ALMA

Chemical signatures indicative of different heating processes

Insights into star formation and black hole influence on interstellar chemistry

Abstract

In external galaxies, some galaxies have higher activities of star formation and central supermassive black holes. The interstellar medium in those galaxies can be heated by different mechanisms such as UV-heating, X-ray heating, cosmic-ray heating, and shock/mechanical heating. Chemical compositions can also be affected by those heating mechanisms. Observations of many molecular species in those nearby galaxies are now possible with the high sensitivity of Atacama Large Millimeter/sub-millimeter Array (ALMA). Here I cover different chemical models for those heating mechanisms. In addition, I present recent ALMA results of extragalactic astrochemistry including our results of a face-on galaxy M83 and an infrared-luminous merger NGC 3256.