# CO excitation in the Seyfert galaxy NGC7130

## TL;DR

This study models the CO spectral energy distribution of NGC7130, revealing how AGN activity influences molecular gas excitation through combined PDR and XDR processes, utilizing multi-band data including ALMA, Chandra, and NuSTAR.

## Contribution

It introduces a comprehensive multi-band modeling approach that combines PDR and XDR models to interpret CO emission in a Seyfert galaxy, highlighting the role of AGN X-ray heating.

## Key findings

- PDRs explain CO lines up to J~6
- X-ray heating accounts for higher J lines
- Composite models reveal molecular cloud properties

## Abstract

We present a coherent multi-band modelling of the CO Spectral Energy Distribution of the local Seyfert Galaxy NGC7130 to assess the impact of the AGN activity on the molecular gas. We take advantage of all the available data from X-ray to the sub-mm, including ALMA data. The high-resolution (~0.2") ALMA CO(6-5) data constrain the spatial extension of the CO emission down to ~70 pc scale. From the analysis of the archival CHANDRA and NuSTAR data, we infer the presence of a buried, Compton-thick AGN of moderate luminosity, L_2-10keV ~ 1.6x10^{43} ergs-1. We explore photodissociation and X-ray-dominated regions (PDRs and XDRs) models to reproduce the CO emission. We find that PDRs can reproduce the CO lines up to J~6, however, the higher rotational ladder requires the presence of a separate source of excitation. We consider X-ray heating by the AGN as a source of excitation, and find that it can reproduce the observed CO Spectral Energy Distribution. By adopting a composite PDR+XDR model, we derive molecular cloud properties. Our study clearly indicates the capabilities offered by current-generation of instruments to shed light on the properties of nearby galaxies adopting state-of-the art physical modelling.