MaNGA AGN dwarf galaxies (MAD)

II. AGN outflows in dwarf galaxies

¹ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Magrans, 08193 Barcelona, Spain
² Institut d’Estudis Espacials de Catalunya (IEEC), Edifici RDIT, Campus UPC, 08860 Castelldefels, (Barcelona), Spain
³ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan, 1, 44001 Teruel, Spain
⁴ Instituto de Física de Cantabria, Avenida de los Castros, s/n, 39005 Santander, Cantabria, Spain
⁵ Instituto de Astrofísica de Canarias, Calle Vía Láctea, s/n, E-38205 La Laguna, Tenerife, Spain
⁶ Departamento de Astrofísica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
⁷ Department of Physics and Materials Science, The University of Memphis, 3720 Alumni Avenue, Memphis, TN 38152, USA

^⋆ Corresponding author: victorproyecto98@gmail.com

Received: 17 December 2024
Accepted: 10 March 2025

Abstract

Context. Feedback from an active galactic nucleus (AGN) is one of the most important mechanisms in galaxy evolution. This phenomenon is usually found in massive galaxies and is known to regulate star formation. Although dwarf galaxies are assumed to be regulated by supernova feedback, recent studies have offered evidence to support the presence of AGN outflows and feedback in dwarf galaxies.

Aims. We investigate the presence of AGN outflows in a sample of 2292 dwarf galaxies with AGN signatures drawn from the MaNGA survey. Thanks to the integral field unit data from MaNGA, we are able to spatially resolve these outflows and study their kinematics and energetics.

Methods. Using the Galaxy/AGN Emission Line Analysis TOol (GELATO) Python code, we fit the AGN-stacked spectrum of each galaxy. This is the stack of all the spaxels classified as AGNs or composites based on their emission line diagnostic diagrams and, in particular, the [OIII]λ5007 Å emission line. If the galaxies exhibited a broad [OIII] emission line component in the stacked spectrum, we ran GELATO through all the spaxels classified as AGNs and composites in the emission line diagnostic diagrams.

Results. We found 13 new dwarf galaxies that present outflow signatures based on the presence of a broad [OIII] emission line component. Their velocity measurement W₈₀ (width containing 80% of the flux of the [OIII]λ5007 Å emission line) ranges from 205 to 566 km s⁻¹ and the kinetic energy rate ranges from ∼10³⁵ to ∼10³⁹ erg s⁻¹. Stellar processes are unlikely to explain these outflow kinetic energy rates in the case of nine dwarf galaxies. We found a correlation between the W₈₀ velocity and the [OIII] luminosity as well as between the kinetic energy rate of the outflow and the bolometric luminosity spanning from massive to dwarf galaxies. This suggests a similar behaviour between the AGN outflows in the dwarf galaxy population and those in massive galaxies.