The life cycle of the Central Molecular Zone - I. Inflow, star formation, and winds
Date
2019
Authors
Armillotta, Lucia
Krumholz, Mark
Di Teodoro, Enrico Maria
McClure-Griffiths, Naomi
Journal Title
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Volume Title
Publisher
Royal Astronomical Society
Abstract
We present a study of the gas cycle and star formation history in the central 500 pc of the
Milky Way, known as Central Molecular Zone (CMZ). Through hydrodynamical simulations
of the inner 4.5 kpc of our Galaxy, we follow the gas cycle in a completely self-consistent
way, starting from gas radial inflow due to the Galactic bar, the channelling of this gas into a
dense, star-forming ring/stream at ≈200–300 pc from the Galactic centre, and the launching
of galactic outflows powered by stellar feedback. We find that star formation activity in the
CMZ goes through oscillatory burst/quench cycles, with a period of tens to hundreds of
Myr, characterized by roughly constant gas mass but order-of-magnitude level variations in
the star formation rate. Comparison with the observed present-day star formation rate of the
CMZ suggests that we are currently near a minimum of this cycle. Stellar feedback drives a
mainly two-phase wind off the Galactic disc. The warm phase dominates the mass flux, and
carries 100–200 per cent of the gas mass converted into stars. However, most of this gas goes
into a fountain and falls back on to the disc rather than escaping the Galaxy. The hot phase
carries most of the energy, with a time-averaged energy outflow rate of 10–20 per cent of the
supernova energy budget.
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Source
Monthly Notices of the Royal Astronomical Society
Type
Journal article
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Open Access
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DOI
10.1093/mnras/stz2880