Simulating Jellyfish Galaxies: A Case Study for a Gas-Rich Dwarf Galaxy

Jaehyun Lee; Taysun Kimm; Jérémy Blaizot; Harley Katz; Wonki Lee; Yun-Kyeong Sheen; Julien Devriendt; Adrianne Slyz

doi:10.3847/1538-4357/ac5595

paper

Simulating Jellyfish Galaxies: A Case Study for a Gas-Rich Dwarf Galaxy

arXiv:2201.01316 · doi:10.3847/1538-4357/ac5595

Abstract

We investigate the formation of jellyfish galaxies using radiation-hydrodynamic simulations of gas-rich dwarf galaxies with a multi-phase interstellar medium (ISM). We find that the ram-pressure-stripped (RPS) ISM is the dominant source of molecular clumps in the near wake within 10 kpc from the galactic plane, while in-situ formation is the major channel for dense gas in the distant tail of the gas-rich galaxy. Only 20% of the molecular clumps in the near wake originate from the intracluster medium (ICM); however, the fraction reaches 50% in the clumps located at $80 kpc$ from the galactic center since the cooling time of the RPS gas tends to be short due to the ISM--ICM mixing ( $≲$ 10 Myr). The tail region exhibits a star formation rate of $0.001 - 0.01 M_{⊙} y r^{- 1}$ , and most of the tail stars are born in the stripped wake within 10 kpc from the galactic plane. These stars induce bright H $α$ blobs in the tail, while H $α$ tails fainter than $6 \times 1 0^{38} erg s^{- 1} kp c^{- 2}$ are mostly formed via collisional radiation and heating due to mixing. We also find that the stripped tails have intermediate X-ray to H $α$ surface brightness ratios (1.5 $≲ F_{X} / F_{H α} ≲$ 20), compared to the ISM ( $≲$ 1.5) or pure ICM ( $≫$ 20). Our results suggest that jellyfish features emerge when the ISM from gas-rich galaxies is stripped by strong ram pressure, mixes with the ICM, and enhances the cooling in the tail.

arXiv comment19 pages, 15 figures; Accepted for publication in ApJ

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