The GECKOS Survey: Resolved, multiphase observations of mass-loading and gas density in the galactic wind of NGC 4666

Autor(en)
Barbara Mazzilli Ciraulo, D. B. Fisher, R. Elliott, A. Fraser-McKelvie, M. R. Hayden, M. Martig, J. van de Sande, A. J. Battisti, J. Bland-Hawthorn, A. D. Bolatto, T. H. Brown, B. Catinella, F. Combes, L. Cortese, T. A. Davis, E. Emsellem, D. A. Gadotti, C. del P. Lagos, X. Lin, A. Marasco, E. Peng, F. Pinna, T. H. Puzia, L. A. Silva-Lima, L. M. Valenzuela, G. van de Ven, J. Wang
Abstrakt

We present a multiphase, resolved study of the galactic wind extending from the nearby starburst galaxy NGC 4666. For this we use VLT/MUSE observations from the GECKOS program and HI data from the WALLABY survey. We identify both ionised and HI gas in a biconical structure extending to at least $z\sim$8 kpc from the galaxy disk, with increasing velocity offsets above the midplane in both phases, consistent with a multiphase wind. The measured electron density, using [SII], differs significantly from standard expectations of galactic winds. We find electron density declines from the galaxy centre to $\sim2$ kpc, then rises again, remaining high ($\sim100-300$ cm$^{-3}$) out to $\sim$5 kpc. We find that HI dominates the mass loading. The total HI mass outflow rate (above $z~>2$ kpc) is between $5-13~M_{\odot}~\rm yr^{-1}$, accounting for uncertainties from disk-blurring and group interactions. The total ionised mass outflow rate (traced by H$α$) is between $0.5~M_{\odot}~\rm yr^{-1}$ and $5~M_{\odot}~\rm yr^{-1}$, depending on $n_e(z)$ assumptions. From ALMA/ACA observations, we place an upper-limit on CO flux in the outflow which correlates to $\lesssim2.9~M_{\odot}~\rm yr^{-1}$. We also show that the entire outflow is not limited to the bicone, but a secondary starburst at the edge generates a more widespread outflow, which should be included in simulations. The cool gas in NGC 4666 wind has insufficient velocity to escape the halo of a galaxy of its mass, especially because most of the mass is present in the slower atomic phase. This strong biconical wind contributes to gas cycling around the galaxy.

Organisation(en)
Institut für Astrophysik
Externe Organisation(en)
Swinburne University of Technology, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), European Southern Observatory (Germany), University of Oklahoma, Liverpool John Moores University (LJMU), University of New South Wales, University of Western Australia, Australian National University, The University of Sydney, University of Maryland, College Park, Herzberg Astronomy and Astrophysics Research Centre, Université de recherche Paris Sciences et Lettres, Collège de France, Cardiff University, Durham University, University of Copenhagen, Peking University, INAF - Osservatorio Astronomico di Padova, NSF’s NOIRLab, Instituto de Astrofísica de Canarias (IAC), Universidad de La Laguna, Pontificia Universidad Católica de Chile, Universidade de São Paulo, Ludwig-Maximilians-Universität München
Journal
Monthly Notices of the Royal Astronomical Society
Band
544
Seiten
3290-3311
Anzahl der Seiten
22
ISSN
0035-8711
DOI
https://doi.org/10.1093/mnras/staf1875
Publikationsdatum
12-2025
Peer-reviewed
Ja
ÖFOS 2012
103003 Astronomie, 103004 Astrophysik
Schlagwörter
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/1c5a3120-8880-483e-bae8-aa511762fdbe