Spikes in the SED and Ripples in the Outskirts of Galaxies

TL;DR

The paper introduces Tidal Analysis, a new method to detect and characterize galactic satellites through disturbances in gas disks, with implications for dark matter detection and galaxy evolution studies.

Contribution

A novel quantitative method, Tidal Analysis, is developed and validated for identifying galactic satellites via gas disk disturbances without optical data.

Findings

Validated method on local spirals with known companions.

Demonstrated applicability across a range of satellite masses.

Explored SEDs and images to link interaction history with observable properties.

Abstract

We describe a new method that allows us to quantitatively characterize galactic satellites from analysis of disturbances in outer gas disks, without requiring knowledge of their optical light. We have demonstrated the validity of this method, which we call Tidal Analysis, by applying it to local spirals with known optical companions, including M51 and NGC 1512. These galaxies span the range from having a low mass companion (~ one-hundredth the mass of the primary galaxy) to a fairly massive companion (~ 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 of the dynamical impact of satellites on galactic disks. Here, we present some preliminary results on the emergent SEDs and images, calculated along the time sequence of these dynamical simulations using the 3-D self-consistent Monte Carlo radiative transfer code RADISHE. We explore star formation prescriptions and how they affect the emergent SEDs and images. Our goal is to identify SED colors that are primarily affected by the galaxy's interaction history, and not significantly affected by the choice of star formation prescription. If successful, we may be able to utilize the emergent UV-IR SED of the primary galaxy to understand its recent interaction history.