The Kennicutt-Schmidt law and the main sequence of galaxies in Newtonian and milgromian dynamics

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F21%3A10438794" target="_blank" >RIV/00216208:11320/21:10438794 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=VBqNm.tVx2" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=VBqNm.tVx2</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/mnras/stab2068" target="_blank" >10.1093/mnras/stab2068</a>

Result language

angličtina

Original language name

The Kennicutt-Schmidt law and the main sequence of galaxies in Newtonian and milgromian dynamics

Original language description

The Kennicutt-Schmidt law is an empirical relation between the star formation rate surface density (Sigma(SFR)) and the gas surface density (Sigma(gas)) in disc galaxies. The relation has a power-law form Sigma(SFR) proportional to Sigma(n)(gas). Assuming that star formation results from gravitational collapse of the interstellar medium, Sigma(SFR) can be determined by dividing Sigma(gas) by the local free-fall time t(ff). The formulation of t(ff) yields the relation between Sigma(SFR) and Sigma(gas), assuming that a constant fraction (epsilon(SFE)) of gas is converted into stars every t(ff). This is done here for the first time using Milgromian dynamics (MOND). Using linear stability analysis of a uniformly rotating thin disc, it is possible to determine the size of a collapsing perturbation within it. This lets us evaluate the sizes and masses of clouds (and their t(ff)) as a function of Sigma(gas) and the rotation curve. We analytically derive the relation Sigma(SFR) proportional to Sigma(n)(gas) both in Newtonian and Milgromian dynamics, finding that n = 1.4. The difference between the two cases is a change only to the constant pre-factor, resulting in increased Sigma(SFR) of up to 25 percent using MOND in the central regions of dwarf galaxies. Due to the enhanced role of disc self-gravity, star formation extends out to larger galactocentric radii than in Newtonian gravity, with the clouds being larger. In MOND, a nearly exact representation of the present-day main sequence of galaxies is obtained if epsilon(SFE) = constant approximate to 1.1 per cent. We also show that empirically found correction terms to the Kennicutt-Schmidt law are included in the here presented relations. Furthermore, we determine that if star formation is possible, then the temperature only affects Sigma(SFR) by at most a factor of root 2.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GA20-21855S" target="_blank" >GA20-21855S: The dynamics of dense star clusters with primordial binaries and massive black holes</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

e-ISSN

—

Volume of the periodical

506

Issue of the periodical within the volume

4

Country of publishing house

GB - UNITED KINGDOM

Number of pages

11

Pages from-to

5468-5478

UT code for WoS article

000705339100055

EID of the result in the Scopus database

2-s2.0-85114454708