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Published January 1, 2018 | Published + Submitted
Journal Article Open

The SAMI Galaxy Survey: understanding observations of large-scale outflows at low redshift with EAGLE simulations

Abstract

This work presents a study of galactic outflows driven by stellar feedback. We extract main-sequence disc galaxies with stellar mass 10^9 ≤ M⋆/ M⊙ ≤ 5.7 × 10^(10) at redshift z = 0 from the highest resolution cosmological simulation of the Evolution and Assembly of GaLaxies and their Environments (EAGLE) set. Synthetic gas rotation velocity and velocity dispersion (σ) maps are created and compared to observations of disc galaxies obtained with the Sydney-AAO (Australian Astronomical Observatory) Multi-object Integral field spectrograph (SAMI), where σ-values greater than 150 km s^(−1) are most naturally explained by bipolar outflows powered by starburst activity. We find that the extension of the simulated edge-on (pixelated) velocity dispersion probability distribution depends on stellar mass and star formation rate surface density (Σ_(SFR)), with low-M⋆/low-Σ_(SFR) galaxies showing a narrow peak at low σ (∼30 km s^(−1)) and more active, high-M⋆/high-Σ_(SFR) galaxies reaching σ > 150 km s^(−1). Although supernova-driven galactic winds in the EAGLE simulations may not entrain enough gas with T <10^5 K compared to observed galaxies, we find that gas temperature is a good proxy for the presence of outflows. There is a direct correlation between the thermal state of the gas and its state of motion as described by the σ-distribution. The following equivalence relations hold in EAGLE: (i) low-σ peak  ⇔ disc of the galaxy  ⇔ gas with T <10^5 K; (ii) high-σ tail  ⇔ galactic winds  ⇔ gas with T ≥10^5 K.

Additional Information

© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 September 5. Received 2017 September 4; in original form 2016 December 5. Published: 09 September 2017. ET would like to thank Lemmy Kilmister for constant inspiration during the writing of this paper and Jeremy Mould & Paul Geil for many insightful discussions. RAC is a Royal Society University Research Fellow. SMC acknowledges the support of an Australian Research Council Future Fellowship (FT100100457). Support for AMM is provided by NASA through Hubble Fellowship grant #HST-HF2-51377 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. The SAMI Galaxy Survey is based on observations made at the Anglo-Australian Telescope. The Sydney-AAO Multi-object Integral field spectrograph (SAMI) was developed jointly by the University of Sydney and the AAO. The SAMI input catalogue is based on data taken from the Sloan Digital Sky Survey, the GAMA Survey and the VST ATLAS Survey. The SAMI Galaxy Survey is funded by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020, and other participating institutions. The SAMI Galaxy Survey website is http://sami-survey.org/. Part of this research was done using the National Computational Infrastructure (NCI) Raijin-distributed memory cluster and supported by the Flagship Allocation Scheme of the NCI National Facility at the Australian National University (ANU). For the post-processing, we used the Edward and Spartan High Performance Computing (HPC) clusters at the University of Melbourne. This work also used the DiRAC Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (http://dirac.ac.uk). The DiRAC system was funded by BIS National E-Infrastructure capital grant ST/K00042X/1, STFC capital grants ST/H008519/1 and ST/K00087X/1, STFC DiRAC Operations grant ST/K003267/1 and Durham University. DiRAC is part of the National E-Infrastructure. This work was supported by STFC grant ST/L00075X/1.

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Additional details

Created:
August 19, 2023
Modified:
October 17, 2023