CAHA/PPAK Integral-field Spectroscopic Observations of M81. I. Circumnuclear Ionized Gas

DOI: 
10.3847/1538-4357/ac56d9
Publication date: 
08/04/2022
Main author: 
Li, Zongnan
IAA authors: 
García-Benito, Rubén
Authors: 
Li, Zongnan;Li, Zhiyuan;García-Benito, Rubén;Feng, Shuai
Journal: 
The Astrophysical Journal
Refereed: 
Yes
Publication type: 
Article
Volume: 
928
Pages: 
111
Abstract: 
Galactic circumnuclear environments of nearby galaxies provide unique opportunities for our understanding of the coevolution between supermassive black holes and their host galaxies. Here, we present a detailed study of ionized gas in the central kiloparsec region of M81, which hosts the closest prototype low-luminosity active galactic nucleus, based on optical integral-field spectroscopic observations taken with the CAHA 3.5 m telescope. It is found that much of the circumnuclear ionized gas is concentrated within a bright core of ~200 pc in extent and a surrounding spiral-like structure known as the nuclear spiral. The total mass of the ionized gas is estimated to be ~2 × 10<SUP>5</SUP> M <SUB>⊙</SUB>, which corresponds to a few percent of the cold gas mass in this region, as traced by co-spatial dust extinction features. Plausible signature of a biconical outflow along the disk plane is suggested by a pair of blueshifted/redshifted low-velocity features, symmetrically located at ~120-250 pc from the nucleus. The spatially resolved line ratios of [N II]/Hα and [O III]/Hβ demonstrate that much of the circumnuclear region can be classified as a LINER. However, substantial spatial variations in the line intensities and line ratios strongly suggest that different ionization/excitation mechanisms, rather than just a central dominant source of photoionization, are simultaneously at work to produce the observed line signatures.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2022ApJ...928..111L/abstract
ADS Bibcode: 
2022ApJ...928..111L
Keywords: 
LINER galaxies;Galaxy nuclei;Warm ionized medium;925;609;1788;Astrophysics - Astrophysics of Galaxies