Finding Dwarf Galaxies From Their Tidal Imprints

TL;DR

This paper introduces Tidal Analysis, a new method to determine the mass and position of galactic companions from gas disk disturbances, validated on local spiral galaxies with known companions.

Contribution

The paper presents a novel, validated technique for inferring galactic companion properties solely from gas disk disturbance analysis.

Findings

Successfully applied to M51 and NGC 1512

Can detect low-mass companions (~1% of primary)

Broad implications for dark matter detection and galaxy evolution

Abstract

We describe ongoing work on a new method that allows one to determine the mass and relative position (in galactocentric radius and azimuth) of galactic companions purely from analysis of observed disturbances in gas disks. Here, we demonstrate the validity of this method, which we call Tidal Analysis, by applying it to local spirals with known optical companions, namely M51 and NGC 1512. These galaxies span the range from having a very low mass companion ($\sim$ one-hundredth the mass of the primary galaxy) to a fairly massive companion ($\sim$ one-third the mass of the primary galaxy). This approach has broad implications for many areas of astrophysics -- for the indirect detection of dark matter (or dark-matter dominated dwarf galaxies), and for galaxy evolution in its use as a decipher for the dynamical impact of satellites on galactic disks. Here, we provide a proof of principle of the method by applying it to infer and quantitatively characterize optically visible galactic companions of local spirals, from the analysis of observed disturbances in outer gas disks.