An improved formalism for measuring the dark matter subhalos mass by its gravitational wake

TL;DR

This paper refines the method for estimating dark matter subhalo masses via gravitational wakes by incorporating nonhomogeneous backgrounds and host halo potentials, validated with Gaia data and simulations, enabling detection of smaller subhalos within 30 kpc.

Contribution

It introduces an improved formalism that accounts for background inhomogeneity and host potential, enhancing subhalo mass estimation accuracy using stellar data.

Findings

Including host halo potential improves mass estimates.

Method is effective for subhalos within 30 kpc.

Inclusion of cloud's circular velocity is crucial for analysis.

Abstract

We reexamined the framework used to determine the dark matter mass of a subhalo using the gravitational effects of its passage upon the stellar halo of a host. In particular, we aim to include different density distribution functions for the perturber and a non homogeneous background due to the host's halo gravitational potential. We have used a sample of K giant and RRLyrae stars based on Gaia DR3 data and two different set of simulations, to test the new formalism. From our analysis, we found that the inclusion of a nonhomogeneous background improves substantially the estimation of the subhalo dark matter mass. The methodology is not sufficiently sensitive to discriminate between different density distribution functions for the perturber, however, in the case of the observational data, the inclussion of the cloud's circular velocity is a fundamental tool to complement the analysis. The results obtained including the host halo potential agree with the independent previous measurements or with the reported value for the subhalo dark matter mass in the simulations. These results show that it is possible to measure the mass of smaller subhalos through their gravitational wake, even for subhalos closer to their host, with distances lower than 30 kpc.