The UV window on counter rotating ETGs: insight from SPH simulations with chemo-photometric implementation

TL;DR

This paper uses SPH simulations with chemo-photometric modeling to study the UV evolution of counter rotating early-type galaxies, revealing insights into their rejuvenation episodes and complex formation history.

Contribution

It introduces a detailed simulation approach combining chemo-photometric data to analyze the UV evolution and rejuvenation in counter rotating ETGs.

Findings

Simulations successfully fit observed properties of NGC 3593 and NGC 5173.

Rejuvenation episodes are identified through UV and color-magnitude diagram analysis.

The study provides a predictive framework for understanding counter rotating ETG evolution.

Abstract

The Galaxy Evolution Explorer (GALEX) detected ultraviolet emission in about 50% of multi-spin early-type galaxies (ETGs), suggesting the occurrence of a recent rejuvenation episode connected to the formation of these kinematical features. With the aim at investigating the complex evolutionary scenario leading to the formation of counter rotating ETGs (CR-ETGs) we use our Smooth Particle Hydrodynamic (SPH) code with chemo-photometric implementation. We discuss here the UV evolutionary path of two CR-ETGs, NGC 3593 and NGC 5173, concurrently best fitting their global observed properties, i.e., morphology, dynamics, as well as their total B-band absolute magnitude and spectral energy distribution (SED) extended over three orders of magnitude in wavelength. These simulations correspond to our predictions about the target evolution which we follow in the color-magnitude diagram (CMD), near-UV (NUV) versus r-band absolute magnitude, as a powerful diagnostic tool to emphasize rejuvenation episodes.