Interacting galaxies on FIRE-2: the connection between enhanced star formation and interstellar gas content
2019; Oxford University Press; Volume: 485; Issue: 1 Linguagem: Inglês
10.1093/mnras/stz417
ISSN1365-2966
AutoresJorge Moreno, Paul Torrey, Sara L. Ellison, David R. Patton, Philip F. Hopkins, Michael Bueno, Christopher C. Hayward, Desika Narayanan, Dušan Kereš, Asa F. L. Bluck, Lars Hernquist,
Tópico(s)Stellar, planetary, and galactic studies
ResumoWe present a comprehensive suite of high-resolution (parsec-scale), idealized (non-cosmological) galaxy merger simulations (24 runs, stellar mass ratio ∼2.5:1) to investigate the connection between interaction-induced star formation and the evolution of the interstellar medium (ISM) in various temperature–density regimes. We use the gizmo code and the second version of the 'Feedback in Realistic Environments' model (FIRE-2), which captures the multiphase structure of the ISM. Our simulations are designed to represent galaxy mergers in the local Universe. In this work, we focus on the 'galaxy-pair period' between first and second pericentric passage. We split the ISM into four regimes: hot, warm, cool, and cold-dense, motivated by the hot, ionized, atomic and molecular gas phases observed in real galaxies. We find that, on average, interactions enhance the star formation rate of the pair (|${\sim }30{{\ \rm per\ cent}}$|, merger-suite sample average) and elevate their cold-dense gas content (|${\sim }18{{\ \rm per\ cent}}$|). This is accompanied by a decrease in warm gas (|${\sim }11{{\ \rm per\ cent}}$|), a negligible change in cool gas (|${\sim }4{{\ \rm per\ cent}}$| increase), and a substantial increase in hot gas (|${\sim }400{{\ \rm per\ cent}}$|). The amount of cold-dense gas with densities above 1000 cm−3 (the cold ultra-dense regime) is elevated significantly (|${\sim }240{{\ \rm per\ cent}}$|), but only accounts for |${\sim }0.15{{\ \rm per\ cent}}$| (on average) of the cold-dense gas budget.
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