We use the Random Forest (RF) algorithm to develop a tool for automated activity classification of galaxies into 5 different classes: Star-forming (SF), AGN, LINER, Composite, and Passive. We train the algorithm on a combination of mid-IR (WISE) and optical photometric data while the true labels (activity classes) are based on emission line ratios. Our classifier is built to be redshift-agnostic and it is applicable to objects up to z ∼0.1. It reaches a completeness >80 % for SF and Passive galaxies, and ∼60 % for AGN. Applying it to an all-sky galaxy catalog (HECATE) reveals a large population of low-luminosity AGNs outside the AGN locus in the standard mid-IR diagnostics.
@article{arxiv.2303.11691,
title = {A versatile classification tool for galactic activity using optical and infrared colors},
author = {Elias Kyritsis and Charalampos Daoutis and Andreas Zezas and Konstantinos Kouroumpatzakis},
journal= {arXiv preprint arXiv:2303.11691},
year = {2023}
}
Comments
3 pages, 3 figures, the manuscript will be published on Memorie della SAIt