Simulations of star forming main sequence galaxies in Milgromian gravity
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We conduct hydrodynamical MOND simulations of isolated disc galaxies over the stellar mass range M∗/M⊙ = 107 - 1011 using the adaptive mesh refinement code PHANTOM OF RAMSES (POR), an adaptation of the RAMSES code with a Milgromian gravity solver. The scale lengths and gas fractions are based on observed galaxies, and the simulations are run for 5 Gyr. The main aim is to see whether existing sub-grid physics prescriptions for star formation and stellar feedback reproduce the observed main sequence and reasonably match the Kennicutt-Schmidt relation that captures how the local and global star formation rates relate to other properties. Star formation in the models starts soon after initialisation and continues as the models evolve. The initialized galaxies indeed evolve to a state which is on the observed main sequence, and reasonably matches the Kennicutt-Schmidt relation. The available formulation of sub-grid physics is therefore adequate and leads to galaxies that largely behave like observed galaxies, grow in radius, and have flat rotation curves - provided we use Milgromian gravitation. Furthermore, the strength of the bars tends to be inversely correlated with the stellar mass of the galaxy, whereas the bar length strongly correlates with the stellar mass. Irrespective of the mass, the bar pattern speed stays constant with time, indicating that dynamical friction does not affect the bar dynamics. The models demonstrate Renzo's rule and form structures at large radii, much as in real galaxies. In this framework, baryonic physics is thus sufficiently understood to not pose major uncertainties in our modelling of global galaxy properties.
Nagesh , S T , Kroupa , P , Banik , I , Famaey , B , Ghafourian , N , Roshan , M , Thies , I , Zhao , H & Wittenburg , N 2023 , ' Simulations of star forming main sequence galaxies in Milgromian gravity ' , Monthly Notices of the Royal Astronomical Society , vol. 519 , no. 4 , stac3645 , pp. 5128–5148 . https://doi.org/10.1093/mnras/stac3645
Monthly Notices of the Royal Astronomical Society
Copyright © 2022 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the final published version of the work, which was originally published at https://doi.org/10.1093/mnras/stac3645.
DescriptionFunding: This work was performed as an MSc thesis project at the University of Bonn. IB is supported by Science and Technology Facilities Council grant ST/V000861/1, which also partially supports HZ. IB acknowledges support from a ‘Pathways to Research’ fellowship from the University of Bonn. IT acknowledges support through the Stellar Populations and Dynamics research (SPODYR) group at the University of Bonn. PK thanks the DAAD-Eastern Europe exchange program for support.
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