High School More Evidence for MOND -- Globular cluster galactic acceleration imprint

[ohwilleke]

Not about wide binary stars, but another new paper with evidence for MOND or a MOND-like theory:

[Submitted on 16 Aug 2023]

The galactic acceleration scale is imprinted on globular cluster systems of early-type galaxies of most masses and on red and blue globular cluster subpopulations​

Michal Bílek, Michael Hilker, Florent Renaud, Tom Richtler, Avinash Chaturvedi, Srdjan Samurović

Context. Globular clusters carry information about the formation histories and gravitational fields of their host galaxies. Bílek et al. (2019, BSR19 hereafter) reported that the radial profiles of volume number density of GCs in GC systems (GCS) follow broken power laws, while the breaks occur approximately at the a0 radii. These are the radii at which the gravitational fields of the galaxies equal the galactic acceleration scale a0=1.2×10−10ms−2 known from the radial acceleration relation or the MOND theory of modified dynamics.

Aims. Our main goals here are to explore whether the results of BSR19 hold true for galaxies of a wider mass range and for the red and blue GCs sub-populations.

Methods. We exploited catalogs of photometric GC candidates in the Fornax galaxy cluster based on ground and space observations and a new catalog of spectroscopic GCs of NGC 1399, the central galaxy of the cluster. For every galaxy, we obtained the parameters of the broken power law density by fitting the on-sky distribution of the GC candidates, while allowing for a constant density of contaminants. The logarithmic stellar masses of our galaxy sample span 8.0-11.4 M⊙.

Results. All investigated GCSs with a sufficient number of members show broken power-law density profiles. This holds true for the total GC population and the blue and red subpopulations. The inner and outer slopes and the break radii agree well for the different GC populations. The break radii agree with the a0 radii typically within a factor of two for all GC color subpopulations. The outer slopes correlate better with the a0 radii than with the galactic stellar masses. The break radii of NGC 1399 vary in azimuth, such that they are greater toward and against the neighboring galaxy NGC 1404.

Comments:	39 pages, ~15 pages main text, 33 figures, 12 tables. Accepted for publication in A&A
Subjects:	Astrophysics of Galaxies (astro-ph.GA)
Cite as:	arXiv:2308.08629 [astro-ph.GA]

 

[member38644]

(or arXiv:2308.08629v1 [astro-ph.GA] for this version)This new paper by Bílek et al. provides further evidence for MOND or a MOND-like theory by examining the distribution of globular clusters in galaxies of various masses and subpopulations. The results show that the density profiles of globular clusters follow broken power laws, with the breaks occurring at the a0 radii, which is consistent with the predictions of MOND. This is an important confirmation of previous studies and expands the evidence for MOND to a wider range of galaxies.

One interesting finding is the variation in azimuth of the break radii of NGC 1399, which suggests that the gravitational fields of neighboring galaxies may also play a role in the distribution of globular clusters. This adds another layer of complexity to the understanding of MOND and the role of gravity in galaxy formation and evolution.

Overall, this paper provides strong support for MOND or a MOND-like theory, and further research in this area will continue to shed light on the nature of gravity and its effects on galaxy dynamics.