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

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

doi:10.1093/mnras/staf1875

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

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

Department of Astrophysics

Publications: Contribution to journal › Article › Peer Reviewed

Abstract

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.

Original language	English
Pages (from-to)	3290-3311
Number of pages	22
Journal	Monthly Notices of the Royal Astronomical Society
Volume	544
Issue number	4
DOIs	https://doi.org/10.1093/mnras/staf1875
Publication status	Published - 1 Dec 2025

Funding

Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. GECKOS is based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO program ID 110.24AS. We wish to thank the ESO staff, and in particular the staff at Paranal Observatory, for carrying out the GECKOS observations. This paper makes use of services that have been provided by AAO Data Central (datacentral.org.au) This paper makes use of the following ALMA data: ADS/JAO.ALMA#2019.1.01804.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC(Canada), NSTCand ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This scientific work uses data obtained from Inyarrimanha Ilgari Bundara/the Murchison Radio-astronomy Observatory. We acknowledge the Wajarri Yamaji People as the Traditional Owners and native title holders of the Observatory site. CSIRO’s ASKAP radio telescope is part of the Australia Telescope National Facility (https://ror.org/05qajvd42). Operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy. ASKAP uses the resources of the Pawsey Supercomputing Research Centre. Establishment of ASKAP, Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radioastronomy Observatory and the Pawsey Supercomputing Research Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. This research has made use of the NASA/IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. This work was supported by STFC grant ST/X001075/1. MM acknowledges support from the UK Science and Technology Facilities Council through grant ST/Y002490/1. LC acknowledges support from the Australian Research Council Discovery Project funding scheme (DP210100337). FP acknowledges support from the Horizon Europe research and innovation programme under the Maria Skłodowska-Curie grant ‘TraNSLate’ no. 101108180, and from the Agencia Estatal de Investigacion´ del Ministerio de Ciencia e Innovacion´ (MCIN/AEI/10.13039/501100011033) under grant (PID2021- 128131NB-I00) and the European Regional Development Fund (ERDF) ‘A way of making Europe’. THP gratefully acknowledges support from the National Agency for Research and Development (ANID) in form of the CATA-Basal FB210003 grant. LASL is supported by Coordenac¸ao˜ de Aperfeic¸oamento de Pessoal de N´ıvel Superior – Brasil (CAPES) – Finance Code 88887.637633/2021-0. LMV acknowledges support by the German Academic Scholarship Foundation (Studienstiftung des deutschen Volkes) and the Marianne-Plehn-Program of the Elite Network of Bavaria.

Austrian Fields of Science 2012

103003 Astronomy
103004 Astrophysics

Keywords

Astrophysics of Galaxies

Access to Document

10.1093/mnras/staf1875Licence: CC BY 4.0

http://adsabs.harvard.edu/abs/2025arXiv250917560M

Cite this

Mazzilli Ciraulo, B., Fisher, D. B., Elliott, R., Fraser-McKelvie, A., Hayden, M. R., Martig, M., van de Sande, J., Battisti, A. J., Bland-Hawthorn, J., Bolatto, A. D., Brown, T. H., Catinella, B., Combes, F., Cortese, L., Davis, T. A., Emsellem, E., Gadotti, D. A., Lagos, C. D. P., Lin, X., ... Wang, J. (2025). The GECKOS Survey: Resolved, multiphase observations of mass-loading and gas density in the galactic wind of NGC 4666. Monthly Notices of the Royal Astronomical Society, 544(4), 3290-3311. https://doi.org/10.1093/mnras/staf1875

@article{1c5a31208880483ebae8aa511762fdbe,

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

abstract = "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\textbackslash{}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 \$\textbackslash{}sim2\$ kpc, then rises again, remaining high (\$\textbackslash{}sim100-300\$ cm\$\textasciicircum{}\{-3\}\$) out to \$\textbackslash{}sim\$5 kpc. We find that HI dominates the mass loading. The total HI mass outflow rate (above \$z\textasciitilde{}>2\$ kpc) is between \$5-13\textasciitilde{}M\_\{\textbackslash{}odot\}\textasciitilde{}\textbackslash{}rm yr\textasciicircum{}\{-1\}\$, accounting for uncertainties from disk-blurring and group interactions. The total ionised mass outflow rate (traced by H\$α\$) is between \$0.5\textasciitilde{}M\_\{\textbackslash{}odot\}\textasciitilde{}\textbackslash{}rm yr\textasciicircum{}\{-1\}\$ and \$5\textasciitilde{}M\_\{\textbackslash{}odot\}\textasciitilde{}\textbackslash{}rm yr\textasciicircum{}\{-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 \$\textbackslash{}lesssim2.9\textasciitilde{}M\_\{\textbackslash{}odot\}\textasciitilde{}\textbackslash{}rm yr\textasciicircum{}\{-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.",

keywords = "Astrophysics of Galaxies",

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

note = "{\textcopyright} The Author(s) 2025. Published by Oxford University Press on behalf of Royal Astronomical Society",

year = "2025",

month = dec,

day = "1",

doi = "10.1093/mnras/staf1875",

language = "English",

volume = "544",

pages = "3290--3311",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "OXFORD UNIV PRESS INC",

number = "4",

}

Mazzilli Ciraulo, B, Fisher, DB, Elliott, R, Fraser-McKelvie, A, Hayden, MR, Martig, M, van de Sande, J, Battisti, AJ, Bland-Hawthorn, J, Bolatto, AD, Brown, TH, Catinella, B, Combes, F, Cortese, L, Davis, TA, Emsellem, E, Gadotti, DA, Lagos, CDP, Lin, X, Marasco, A, Peng, E, Pinna, F, Puzia, TH, Silva-Lima, LA, Valenzuela, LM, van de Ven, G & Wang, J 2025, 'The GECKOS Survey: Resolved, multiphase observations of mass-loading and gas density in the galactic wind of NGC 4666', Monthly Notices of the Royal Astronomical Society, vol. 544, no. 4, pp. 3290-3311. https://doi.org/10.1093/mnras/staf1875

TY - JOUR

T1 - The GECKOS Survey: Resolved, multiphase observations of mass-loading and gas density in the galactic wind of NGC 4666

AU - Mazzilli Ciraulo, Barbara

AU - Fisher, D. B.

AU - Elliott, R.

AU - Fraser-McKelvie, A.

AU - Hayden, M. R.

AU - Martig, M.

AU - van de Sande, J.

AU - Battisti, A. J.

AU - Bland-Hawthorn, J.

AU - Bolatto, A. D.

AU - Brown, T. H.

AU - Catinella, B.

AU - Combes, F.

AU - Cortese, L.

AU - Davis, T. A.

AU - Emsellem, E.

AU - Gadotti, D. A.

AU - Lagos, C. del P.

AU - Lin, X.

AU - Marasco, A.

AU - Peng, E.

AU - Pinna, F.

AU - Puzia, T. H.

AU - Silva-Lima, L. A.

AU - Valenzuela, L. M.

AU - van de Ven, G.

AU - Wang, J.

PY - 2025/12/1

Y1 - 2025/12/1

N2 - 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.

AB - 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.

KW - Astrophysics of Galaxies

U2 - 10.1093/mnras/staf1875

DO - 10.1093/mnras/staf1875

M3 - Article

SN - 0035-8711

VL - 544

SP - 3290

EP - 3311

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 4

ER -

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

Abstract

Funding

Austrian Fields of Science 2012

Keywords

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