MOND provides an alternative explanation to dark matter for the dynamics of spiral galaxies. We take spiral galaxies from MONDian simulations and construct the dark matter halos needed to explain the stellar accelerations in the disk. We then look at the differences between the MONDian and dark matter predictions for stars out of the plane and show that these might be within reach of next-generation measurements of stellar spectra.
Abstract
We quantify the differences between stellar accelerations in disk galaxies formed in a MONDian universe relative to galaxies with the identical baryonic matter distributions and afitted cold dark matter halo. In a Milky Way-like galaxy the maximal transverse acceleration is 𝒪(10) arcseconds per year per decade, well beyond even the most optimistic extrapolations of current capabilities. Conversely, the maximum difference in the line-of-sightacceleration is 𝒪(1) centimetre per second per decade at solar distances from thegalactic centre. This level of precision is within reach of plausible future instruments.
- Finan-Jenkin and Easther
- Inside MOND: testing gravity with stellar accelerations
- JCAP 11 (2023) 035 or ArXiV:2306.15939
Difference in line-of-sight acceleration for observers 7 (upper) and 9 (lower) kpc from the centre of a large MONDian spiral galaxy and the equivalent dark matter halo.