Mass inflow rate into the Central Molecular Zone: observational determination and evidence of episodic accretion

Sormani, Mattia C.; Barnes, Ashley

doi:10.1093/mnras/stz046

Cited by 80 publications

(101 citation statements)

References 67 publications

(93 reference statements)

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“…Since it is a transient feature, we prefer not to use it as an indicator to constrain the possible existence of the soliton core. The observed ∞-shape of the CMZ might be caused by a recent inflow, as suggested in Sormani & Barnes (2019).…”

Section: The 3d Structure Of the Cmzmentioning

confidence: 74%

Testing the Prediction of Fuzzy Dark Matter Theory in the Milky Way Center

Shen

Schive

2020

ApJ

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The fuzzy dark matter model (FDM, also known as quantum wave dark matter model) argues that light bosons with a mass of ∼ 10 −22 eV are a possible candidate for dark matter in the Universe. One of the most important predictions of FDM is the formation of a soliton core instead of a density cusp at the center of galaxies. If FDM is the correct theory of dark matter, then the predicted soliton core can help to form the Central Molecular Zone (CMZ) in the Milky Way. We present high-resolution hydrodynamical simulations of gas flow patterns to constrain the properties of the soliton core based on a realistic Milky Way potential. We find that a dense center is required to form a reasonable CMZ. The size and kinematics of the CMZ offer a relatively strong constraint on the inner enclosed mass profile of the Galaxy. If a soliton core is not considered, a compact nuclear bulge alone with a radially varying mass-to-light ratio can match the observed size and kinematics of the CMZ. A soliton core model with a mass of ≈ 4.0 × 10 8 M and a core radius of ≈ 0.05 kpc, together with a less massive nuclear bulge with a constant mass-to-light ratio, also agrees nicely with the current data. Such a FDM soliton core corresponds to a boson mass of ∼ 2 − 7 × 10 −22 eV, which could be further constrained by the improved determination of the mass-to-light ratio in the Galactic center.

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Section: The 3d Structure Of the Cmzmentioning

confidence: 74%

Testing the Prediction of Fuzzy Dark Matter Theory in the Milky Way Center

Shen

Schive

2020

ApJ

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“…Beuther et al 2017), they induce strong radial transport and suppress star formation (e.g. Khoperskov et al 2018;Sormani & Barnes 2019), and they drive nuclear starbursts (e.g. Peeples & Martini 2006).…”

Section: Influence Of the Barmentioning

confidence: 99%

The lifecycle of molecular clouds in nearby star-forming disc galaxies

Chevance

Kruijssen

Hygate

et al. 2019

Monthly Notices of the Royal Astronomical Society

255

300

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It remains a major challenge to derive a theory of cloud-scale ( 100 pc) star formation and feedback, describing how galaxies convert gas into stars as a function of the galactic environment. Progress has been hampered by a lack of robust empirical constraints on the giant molecular cloud (GMC) lifecycle. We address this problem by systematically applying a new statistical method for measuring the evolutionary timeline of the GMC lifecycle, star formation, and feedback to a sample of nine nearby disc galaxies, observed as part of the PHANGS-ALMA survey. We measure the spatially-resolved (∼ 100 pc) CO-to-Hα flux ratio and find a universal de-correlation between molecular gas and young stars on GMC scales, allowing us to quantify the underlying evolutionary timeline. GMC lifetimes are short, typically 10−30 Myr, and exhibit environmental variation, between and within galaxies. At kpc-scale molecular gas surface densities Σ H 2 8 M pc −2 , the GMC lifetime correlates with time-scales for galactic dynamical processes, whereas at Σ H 2 8 M pc −2 GMCs decouple from galactic dynamics and live for an internal dynamical time-scale. After a long inert phase without massive star formation traced by Hα (75−90 per cent of the cloud lifetime), GMCs disperse within just 1−5 Myr once massive stars emerge. The dispersal is most likely due to early stellar feedback, causing GMCs to achieve integrated star formation efficiencies of 4−10 per cent. These results show that galactic star formation is governed by cloud-scale, environmentally-dependent, dynamical processes driving rapid evolutionary cycling. GMCs and HII regions are the fundamental units undergoing these lifecycles, with mean separations of 100−300 pc in star-forming discs. Future work should characterise the multi-scale physics and mass flows driving these lifecycles.

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“…The transition happens through dust lanes that carry gas from the x 1 orbits to the x 2 orbits. Recently, Sormani & Barnes (2019) have modelled 12 CO data of the inner Galaxy to determine the mass inflow rate along the dust lanes towards the CMZ. They estimated a total inflow of ∼ 2.7 M yr −1 , thus showing that only a few percent of inflowing gas is converted into stars.…”

Section: Introductionmentioning

confidence: 99%

The life cycle of the Central Molecular Zone – I. Inflow, star formation, and winds

Armillotta

Krumholz

Teodoro

et al. 2019

Monthly Notices of the Royal Astronomical Society

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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, characterised 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% of the gas mass converted into stars. However, most of this gas goes into a fountain and falls back onto 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% of the supernova energy budget.

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Mass inflow rate into the Central Molecular Zone: observational determination and evidence of episodic accretion

Cited by 80 publications

References 67 publications

Testing the Prediction of Fuzzy Dark Matter Theory in the Milky Way Center

Testing the Prediction of Fuzzy Dark Matter Theory in the Milky Way Center

The lifecycle of molecular clouds in nearby star-forming disc galaxies

The life cycle of the Central Molecular Zone – I. Inflow, star formation, and winds

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