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The Iκεα model of feedback-regulated galaxy formation

Sharma, Mahavir; Theuns, Tom

The Iκεα model of feedback-regulated galaxy formation Thumbnail


Mahavir Sharma


We present the Iκεα model of galaxy formation, in which a galaxy’s star formation rate is set by the balance between energy injected by feedback from massive stars and energy lost by the deepening of the potential of its host dark matter halo due to cosmological accretion. Such a balance is secularly stable provided that the star formation rate increases with the pressure in the star forming gas. The Iκεα model has four parameters that together control the feedback from star formation and the cosmological accretion rate onto a halo. Iκεα reproduces accurately the star formation rate as a function of halo mass and redshift in the EAGLE hydrodynamical simulation, even when all four parameters are held constant. It predicts the emergence of a star forming main sequence along which the specific star formation rate depends weakly on stellar mass with an amplitude that increases rapidly with redshift. We briefly discuss the emerging mass-metallicity relation, the evolution of the galaxy stellar mass function, and an extension of the model that includes feedback from active galactic nuclei (AGN). These self-regulation results are independent of the star formation law and the galaxy’s gas content. Instead, star forming galaxies are shaped by the balance between stellar feedback and cosmological accretion, with accurately accounting for energy losses associated with feedback a crucial ingredient.


Sharma, M., & Theuns, T. (2020). The Iκεα model of feedback-regulated galaxy formation. Monthly Notices of the Royal Astronomical Society, 492(2), 2418-2436.

Journal Article Type Article
Acceptance Date Oct 7, 2019
Online Publication Date Nov 14, 2019
Publication Date Feb 28, 2020
Deposit Date Dec 12, 2019
Publicly Available Date Dec 13, 2019
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 492
Issue 2
Pages 2418-2436


Accepted Journal Article (1.1 Mb)

Copyright Statement
This article has been accepted for publication in the Monthly notices of the Royal Astronomical Society ©: 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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