Stellar feedback in M83 as observed with MUSE

I. Overview, an unprecedented view of the stellar and gas kinematics and evidence of outflowing gas

¹ The Oskar Klein Center, Department of Astronomy, Stockholm University, AlbaNova, 10691 Stockholm, Sweden
e-mail: lorenza.dellabruna@astro.su.se
² Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France
³ Department of Physics, University of Alberta, Edmonton AB T6G 2E1, Canada
⁴ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße 1, 85748 Garching, Germany
⁵ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
⁶ Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, 69230 Saint-Genis-Laval, France
⁷ Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, Ohio 43210, USA
⁸ The William H. Miller III Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore 21218, USA
⁹ Centre for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham DH1 3LE, UK
¹⁰ Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK
¹¹ Department of Astronomy and Theoretical Physics, Lund Observatory, Box 43 221 00 Lund, Sweden
¹² Département de physique, de génie physique et d’optique, Université Laval, Quebec, Canada
¹³ Canada-France-Hawaii Telescope, Kamuela 96743, USA
¹⁴ Department of Physics and Astronomy, University of Hawaii, Hilo 96720-4091, USA
¹⁵ European Space Agency (ESA), ESA Office, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore 21218, USA

Received: 27 September 2021
Accepted: 1 February 2022

Abstract

Context. Young massive stars inject energy and momentum into the surrounding gas, creating a multi-phase interstellar medium (ISM) and regulating further star formation. The main challenge of studying stellar feedback proves to be the variety of scales spanned by this phenomenon, ranging from the immediate surrounding of the stars (H II regions, 10s pc scales) to galactic-wide kiloparsec scales.

Aims. We present a large mosaic (3.8 × 3.8 kpc) of the nearby spiral galaxy M83, obtained with the MUSE instrument at ESO Very Large Telescope. The integral field spectroscopy data cover a large portion of the optical disk at a resolution of ∼20 pc, allowing the characterisation of single H II regions while sampling diverse dynamical regions in the galaxy.

Methods. We obtained the kinematics of the stars and ionised gas, and compared them with molecular gas kinematics observed in CO(2-1) with the ALMA telescope array. We separated the ionised gas into H II regions and diffuse ionised gas (DIG) and investigated how the fraction of Hα luminosity originating from the DIG (f_DIG) varies with galactic radius.

Results. We observe that both stars and gas trace the galactic disk rotation, as well as a fast-rotating nuclear component (30″ ≃ 700 pc in diameter), likely connected to secular processes driven by the galactic bar. In the gas kinematics, we observe a stream east of the nucleus (50″ ≃ 1250 pc in size), redshifted with respect to the disk. The stream is surrounded by an extended ionised gas region (1000 × 1600 pc) with enhanced velocity dispersion and a high ionisation state, which is largely consistent with being ionised by slow shocks. We interpret this feature as either the superposition of the disk and an extraplanar layer of DIG, or as a bar-driven inflow of shocked gas. A double Gaussian component fit to the Hα line also reveals the presence of a nuclear biconic structure whose axis of symmetry is perpendicular to the bar. The two cones (20″ ≃ 500 pc in size) appear blue- and redshifted along the line of sight. The cones stand out for having an Hα emission separated by up to 200 km s⁻¹ from that of the disk, and a high velocity dispersion ∼80–200 km s⁻¹. At the far end of the cones, we observe that the gas is consistent with being ionised by shocks. These features had never been observed before in M83; we postulate that they are tracing a starburst-driven outflow shocking into the surrounding ISM. Finally, we obtain f_DIG ∼ 13% in our field of view, and observe that the DIG contribution varies radially between 0.8 and 46%, peaking in the interarm region. We inspect the emission of the H II regions and DIG in ‘BPT’ diagrams, finding that in H II regions photoionisation accounts for 99.8% of the Hα flux, whereas the DIG has a mixed contribution from photoionisation (94.9%) and shocks (5.1%).