2023/04/18 by Zinger, Elad, Joshi, Gandhali, Pillepich, Annalisa +2 · 1 citation
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2304.09202
We present the ``Cosmological Jellyfish'' project - a citizen-science classification program to identify jellyfish galaxies within the IllustrisTNG cosmological simulations. Jellyfish (JF) are satellite galaxies that exhibit long trailing gas features -- `tails' -- extending from their stellar body. Their distinctive morphology arises due to ram-pressure stripping (RPS) as they move through the background gaseous medium. Using the TNG50 and TNG100 simulations, we construct a sample of ∼ 80,000 satellite galaxies spanning an unprecedented range of stellar masses, 108.3-12.3 M_\odot, and host masses of M200,c=1010.4-14.6 M_\odot back to z=2 \citep[extending the work of][]yunjellyfish2019. Based on this sample, ∼ 90,000 galaxy images were presented to volunteers in a citizen-science project on the Zooniverse platform who were asked to determine if each galaxy image resembles a jellyfish. Based on volunteer votes, each galaxy was assigned a score determining if it is a JF or not. This paper describes the project, the inspected satellite sample, the methodology, and the classification process that resulted in a dataset of 5,307 visually-identified jellyfish galaxies. We find that JF galaxies are common in nearly all group- and cluster-sized systems, with the JF fraction increasing with host mass and decreasing with satellite stellar mass. We highlight JF galaxies in three relatively unexplored regimes: low-mass hosts of M200,c∼1011.5-13 M_\odot, radial positions within hosts exceeding the virial radius R200,c, and at high redshift up to z=2. The full dataset of our jellyfish scores is publicly available and can be used to select and study JF galaxies in the IllustrisTNG simulations.