University of Hertfordshire

From the same journal

From the same journal

By the same authors

Galactic 26Al traces metal loss through hot chimneys

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  • staa3612

    Final published version, 5.62 MB, PDF document

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Original languageEnglish
Pages (from-to)210-218
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume501
Issue1
Early online date24 Nov 2020
DOIs
Publication statusPublished - 1 Feb 2021

Abstract

Radioactive 26Al is an excellent tracer for metal ejection in the Milky Way, and can provide a direct constraint on the modelling of supernova feedback in galaxy evolution. Gamma-ray observations of the 26Al decay line have found high velocities and hence require a significant fraction of the Galactic 26Al in the hot component. At the same time, meteoritic data combined with simulation results suggest that a significant amount of 26Al makes its way into stars before decay. We investigated the distribution into hot and cold channels with a simulation of a Milky-Way-like galaxy with massive-star feedback in superbubbles and with ejecta traced by 26Al. About 30-40 per cent of the ejecta remain hot, with typical cooling times of the order Gyr. 26Al traces the footpoints of a chimney-fed outflow that mixes metals turbulently into the halo of the model galaxy on a scale of at least 50 kpc. The rest diffuses into cold gas 104 K, and may therefore be quickly available for star formation. We discuss the robustness of the result by comparison to a simulation with a different global flow pattern. The branching ratio into hot and cold components is comparable to that of longer term average results from chemical evolution modelling of galaxies, clusters, and the intracluster medium.

Notes

© 2020 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is the accepted manuscript version of an article which has been published in final form at https://dx.doi.org/10.1093/mnras/staa3612

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