Inside MOND: Testing Gravity with Stellar Accelerations

TL;DR

This paper compares stellar accelerations in galaxies under MOND and dark matter models, finding differences in line-of-sight accelerations that could be detectable with future instruments, aiding in testing gravity theories.

Contribution

It provides a quantitative analysis of stellar acceleration differences between MOND and dark matter models, highlighting observable signatures for future experiments.

Findings

Maximum transverse acceleration difference is negligible (~10^{-9}) arcseconds per year per decade.

Maximum line-of-sight acceleration difference is about 1 cm/sec per decade at solar distances.

Future instruments could detect these acceleration differences, enabling tests of gravity models.

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 a fitted cold dark matter halo. In a Milky Way-like galaxy the maximal transverse acceleration is ${\cal {O}}(10^{-9})$ arcseconds per year per decade, well beyond even the most optimistic extrapolations of current capabilities. Conversely, the maximum difference in the line-of-sight acceleration is ${\cal {O}}(1)$ centimetre per second per decade at solar distances from the galactic centre. This level of precision is within reach of plausible future instruments.