# Integral Field Spectroscopy of the inner kpc of the elliptical galaxy NGC 5044

## TL;DR

This study uses integral field spectroscopy to analyze the stellar populations, gas kinematics, and ionization mechanisms in the inner kiloparsec of NGC 5044, revealing a weak AGN, a rotating gas disk, and filamentary inflows.

## Contribution

First detailed integral field spectroscopic analysis of NGC 5044's nuclear region, identifying a broad Hα component and gas inflows fueling the AGN.

## Key findings

- Presence of a broad Hα emission line in the nucleus.
- Detection of a rotating gas disk with a velocity of ~240 km/s.
- Mass inflow rate of ~0.4 solar masses per year sufficient to power the AGN.

## Abstract

We used Gemini Multi-Object Spectrograph (GMOS) in the Integral Field Unit mode to map the stellar population, emission line flux distributions and gas kinematics in the inner kpc of NGC 5044. From the stellar populations synthesis we found that the continuum emission is dominated by old high metallicity stars ($\sim$13 Gyr, 2.5Z$\odot$). Also, its nuclear emission is diluted by a non thermal emission, which we attribute to the presence of a weak active galactic nuclei (AGN). In addition, we report for the first time a broad component (FWHM$\sim$ 3000km$s^{-1}$) in the H$\alpha$ emission line in the nuclear region of NGC 5044. By using emission line ratio diagnostic diagrams we found that two dominant ionization processes coexist, while the nuclear region (inner 200 pc) is ionized by a low luminosity AGN, the filamentary structures are consistent with being excited by shocks. The H$\alpha$ velocity field shows evidence of a rotating disk, which has a velocity amplitude of $\sim$240kms$^{-1}$ at $\sim$ 136 pc from the nucleus. Assuming a Keplerian approach we estimated that the mass inside this radius is $1.9\times10^9$ $M_{\odot}$, which is in agreement with the value obtained through the M-$\sigma$ relation, $ M_{SMBH}=1.8\pm1.6\times10^{9}M_{\odot}$. Modelling the ionized gas velocity field by a rotating disk component plus inflows towards the nucleus along filamentary structures, we obtain a mass inflow rate of $\sim$0.4 M$_\odot$. This inflow rate is enough to power the central AGN in NGC 5044.