NGC 2419 does not challenge MOND, Part 2

TL;DR

This paper argues that NGC 2419 does not challenge MOND, presenting a new polytropic model that better fits observational data while discussing the limitations of such tests.

Contribution

It introduces a novel polytropic model with a running index that improves the fit to NGC 2419 data within the MOND framework.

Findings

New polytropic model fits surface brightness and velocity dispersion data

Systematic effects undermine the significance of observational discrepancies

Pressure-supported objects have intrinsic limitations as gravity tests

Abstract

I argue that, despite repeated claims of Ibata et al., the globular cluster NGC 2419 does not pose a problem for modified Newtonian dynamics (MOND). I present a new polytropic model with a running polytropic index. This model provides an improved representation of the radial distribution of surface brightness while maintaining a reasonable fit to the velocity dispersion profile. Although it may be argued that the differences with these observations remain large compared to the reported random errors, there are several undetectable systematic effects which render a formal likelihood analysis irrelevant. I comment generally upon these effects and upon the intrinsic limitations of pressure supported objects as tests of gravity.