Back to the Green Valley: How to Rejuvenate an S0 Galaxy through Minor Mergers

Galaxies

Michela Mapelli¹  Alexei Moiseev¹  José Alfonso López Aguerri¹ 

[1] INAF—Astronomical Observatory of Padova, Vicolo dell’Osservatorio 5, Padova 35122, Italy; E-Mail

关键词: galaxies: interactions;    methods: numerical;    galaxies: kinematics and dynamics;    galaxies: ISM;    galaxies: star formation;   

DOI  :  10.3390/galaxies3040192

来源: mdpi

【 摘 要 】

About half of the S0 galaxies in the nearby Universe show signatures of recent or ongoing star formation. Whether these S0 galaxies were rejuvenated by the accretion of fresh gas is still controversial. We study minor mergers of a gas-rich dwarf galaxy with an S0 galaxy, by means of N-body smoothed-particle hydrodynamics simulations. We find that minor mergers trigger episodes of star formation in the S0 galaxy, lasting for ∼10 Gyr. One of the most important fingerprints of the merger is the formation of a gas ring in the S0 galaxy. The ring is reminiscent of the orbit of the satellite galaxy, and its lifetime depends on the merger properties: polar and counter-rotating satellite galaxies induce the formation of long-lived smooth gas rings.

【 授权许可】

CC BY   
© 2015 by the author; licensee MDPI, Basel, Switzerland.