Testable predictions to distinguish between MOND and dark matter theories are valuable.
Multiple studies on radial migration in disc galaxies have proven the importance of the effect of resonances with non-axisymmetric components on the evolution of galactic discs. However, the dynamical effects of classic Newtonian dynamics with dark matter (DM) differ from MOdified Newtonian Dynamics (MOND) and might trigger different radial migration. A thorough analysis of radial migration considering these two gravitational regimes might shed some light on different predictions of DM and MOND theories. We aim to quantitatively and qualitatively compare the effects of resonances and stellar radial migration (churning) in a Milky Way-like (MW-like) galaxy in the DM and MOND regimes. We performed simulations of a MW-like galaxy to analyse the effect of non-axisymmetric structures (galactic bar and spiral arms) considering various parameters of the spiral structure. We conducted a two-dimensional numerical simulation consisting of the integration of 2⋅10^6 stars in a static rotating galactic potential for 6 Gyr. We analysed the change in the star's position, the guiding radius, as well as the frequency phase space. We investigated DM and MOND approaches. The outcome of the simulation shows that the radial migration is much more pronounced in the MOND regime compared to the DM one. Compared to the DM approach, in the MOND regime, we observe up to five times as many stars with a maximum change in the guiding radius of more than 1.5 kpc during the time interval from 2−6 Gyr. Analysis of the frequency phase space reveals that the most prominent resonances in all DM and MOND configurations are the co-rotation resonance with the spiral arms (m=p=1), outer Lindblad resonance with the galactic bar and spiral arms, and the co-rotation resonance (m=2, p=1) with the superposition of the galactic bar and spiral arms, 2Ω=Ωb+Ωsp.
R. Nagy, F. Janák, M. Šturc, M. Jurčík, E. Puha, "Comparing radial migration in dark matter and MOND regimes" arXiv:2501.05924 (January 10, 2025).
5 comments:
what fits the data and observation better ?
It is an ex ante prediction. There aren't observations sufficient to assess it yet, but such observations will probably be possible in the near future.
FYI. There was a recent X17 paper which I didn't blog because it was a speculative effort to fit a different kind of hypothetical particle to the claimed anomaly rather than adding new experimental data or conducting an even handed analysis. https://arxiv.org/abs/2501.05507
Our analysis shows that a spin-2 state is highly disfavoured by the SINDRUM constraint while a scalar boson could explain the Helium and Carbon anomalies while being compatible with other experimental constraints.
thanks and events for X17
https://indico.cern.ch/event/1454048/contributions/6289379/
UCLA Dark Matter 2025
Searching for dark sectors and X17 with PADME
Mar 26, 2025, 3:00 PM
Andre Frankenthal (Princeton University (US))
Description
PADME is a fixed-target, missing-mass experiment originally designed to search for dark photons using a beam of positrons with energy up to 500 MeV. The detector, located at the Laboratori Nazionali di Frascati, in Italy, has already collected initial physics data over the last few years. More recently, the experiment has been adapted to perform a direct search for on-shell X17 production. PADME will be able to provide independent confirmation of the anomalies observed in the ATOMKI spectroscopic measurements with Beryllium, Helium, and Carbon atoms. The new experimental setup and the prospects for the observation of X17 production will be discussed, and new upgrades to the detector that will greatly expand the physics program of PADME will be introduced.
The date for that paper seems problematic to me as it comes from a couple of months in the future, but maybe you are prescient.
Post a Comment