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

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 non-homogeneous 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 inclusion 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 subhaloes through their gravitational wake, even for subhaloes closer to their host, with distances lower than 30 kpc.