Predicting the Properties of the Remnants of Dissipative Galaxy Mergers

TL;DR

This paper introduces a physically motivated model to predict the properties of galaxy merger remnants, accounting for dissipative effects and calibrated with simulations, useful for semi-analytic galaxy formation models.

Contribution

The paper presents a new model that accurately predicts galaxy merger remnants' properties using initial conditions and orbital parameters, incorporating dissipative effects.

Findings

Predicts remnant stellar mass, radius, velocity dispersion with 25% accuracy

Valid for both major and minor galaxy mergers

Provides a practical recipe for semi-analytic galaxy formation models

Abstract

We construct a physically motivated model for predicting the properties of the remnants of gaseous galaxy mergers, given the properties of the progenitors and the orbit. The model is calibrated using a large suite of SPH merger simulations. It implements generalized energy conservation while accounting for dissipative energy losses and star formation. The dissipative effects are evaluated from the initial gas fractions and from the orbital parameters via an "impulse" parameter, which characterizes the strength of the encounter. Given the progenitor properties, the model predicts the remnant stellar mass, half-mass radius, and velocity dispersion to an accuracy of 25%. The model is valid for both major and minor mergers. We provide an explicit recipe for semi-analytic models of galaxy formation.