We investigate the formation of jellyfish galaxies using radiation-hydrodynamic simulations of gas-rich dwarf galaxies with a multiphase 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 owing to the ISM-ICM mixing (≲10 Myr). The tail region exhibits a star formation rate of 0.001-0.01 M ⊙ yr-1, and most of the tail stars are born in the stripped wake within 10 kpc from the galactic plane. These stars induce bright Hα blobs in the tail, while Hα tails fainter than 6 × 1038 erg s-1 kpc-2 are mostly formed via collisional radiation and heating due to mixing. We also find that the stripped tails have intermediate X-ray-to-Hα surface brightness ratios (1.5 ≲ F X/F Hα ≲ 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.
|Publication status||Published - 2022 Apr 1|
Bibliographical noteFunding Information:
The authors would like to thank the anonymous referee for their constructive review of this manuscript. The authors also thank Ming Sun for helpful comments on the comparison of X-ray luminosities. J.L. is supported by the National Research Foundation of Korea (grant No. NRF-2021R1C1C2011626). T.K. is supported by the National Research Foundation of Korea (grant No. NRF-2020R1C1C1007079) and acted as the corresponding author. Y.-K.S. acknowledges support from the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT (grant No. NRF-2019R1C1C1010279). The supercomputing time for numerical simulations was kindly provided by KISTI (grant No. KSC-2020-CRE-0278), and large data transfer was supported by KREONET, which is managed and operated by KISTI. This work is supported by the Center for Advanced Computation at Korea Institute for Advanced Study. This work was also performed using the DiRAC Data Intensive service at Leicester, operated by the University of Leicester IT Services, which forms part of the STFC DiRAC HPC Facility ( www.dirac.ac.uk ). The equipment was funded by BEIS capital funding via STFC capital grants ST/K000373/1 and ST/R002363/1 and STFC DiRAC Operations grant ST/R001014/1. DiRAC is part of the National e-Infrastructure.
© 2022. The Author(s). Published by the American Astronomical Society.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science