Jellyfish galaxies with the IllustrisTNG simulations - when, where, and for how long does ram pressure stripping of cold gas occur?

Eric Rohr*, Annalisa Pillepich, Dylan Nelson, Elad Zinger, Gandhali D. Joshi, Mohammadreza Ayromlou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Jellyfish galaxies are prototypical examples of satellite galaxies undergoing strong ram pressure stripping (RPS). We analyse the evolution of 512 unique, first-infalling jellyfish galaxies from the TNG50 cosmological simulation. These have been visually inspected to be undergoing RPS sometime in the past 5 Byr (since z = 0.5), have satellite stellar masses, and live in hosts with at z = 0. We quantify the cold gas (T ≤ 104.5 K) removal using the tracer particles, confirming that for these jellyfish, RPS is the dominant driver of cold gas loss after infall. Half of these jellyfish are completely gas-less by z = 0, and these galaxies have earlier infall times and smaller satellite-to-host mass ratios than their gaseous counterparts. RPS can act on jellyfish galaxies over long time-scales of ≈1.5-8 Gyr. Jellyfish in more massive hosts are impacted by RPS for a shorter time span and, at a fixed host mass, jellyfish with less cold gas at infall and lower stellar masses at z = 0 have shorter RPS time spans. While RPS may act for long periods of time, the peak RPS period - where at least 50 per cent of the total RPS occurs - begins within ≈1 Gyr of infall and lasts 2 Gyr. During this period, the jellyfish are at host-centric distances ∼0.2-2R200c, illustrating that much of RPS occurs at large distances from the host galaxy. Interestingly, jellyfish continue forming stars until they have lost ≈98 per cent of their cold gas. For groups and clusters in TNG50, jellyfish galaxies deposit more cold gas () into haloes than what exists in them at z = 0, demonstrating that jellyfish, and in general satellite galaxies, are a significant source of cold gas accretion.

Original languageAmerican English
Pages (from-to)3502-3525
Number of pages24
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - 1 Sep 2023

Bibliographical note

Publisher Copyright:
© 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.


  • galaxies: clusters: intracluster medium
  • galaxies: evolution
  • galaxies: formation
  • galaxies: haloes
  • galaxies: interactions
  • methods: numerical


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