Molecular gas and dust in spiral galaxies

Wilson, C. D.

doi:10.1017/s174392131300077x

Cited by 2 publications

(1 citation statement)

References 30 publications

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“…In particular, it is a cooling time of < 1 Gyr within 10 kpc that allows for the formation of molecular gas; this is the 'cooling time threshold' (Cavagnolo et al, 2008Rafferty et al, 2008Hogan et al, 2017 which has been observed to be a reasonably sharp cut-off in the presence of molecular gas in early-types and brightest cluster galaxies (BCGs). In early-types, it is only possible to get molecular gas if you are below this cooling time threshold -but in spiral galaxies molecular gas is present regardless (e.g., Wilson, 2013). This points to the conclusion that in early-types it is the simple condensation of the hot corona that gives rise to molecular gas, but in spiral galaxies such as the MW there is an additional mechanism occurring that does the job.…”

Section: Introductionmentioning

confidence: 99%

Positive feedback at the disc-halo interface

Hobbs,

Feldmann

2020

Preprint

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The flat star formation (SF) history of the Milky Way (MW) requires gas in the Galactic disc to be replenished, most likely from a reservoir outside the Galaxy. Such a replenishment may be achieved by a form of 'positive' feedback, whereby SF feedback creates a Galactic fountain cycle that collects and cools additional gas from the hot halo surrounding the Galaxy. In this paper we present a model of this process for the MW. A section of the Galactic disc is allowed to form stars which subsequently explode as supernovae (SNe) and send gas out into the hot halo. The gas that is sent out is colder than the hot halo gas and, as it mixes, the halo gas is cooled, providing fuel for further SF as the mixture falls back onto the Galactic disc. We find that this process can be sufficient to maintain a roughly-constant cold gas mass in the MW over at least 3 Gyr. Our results further suggest that there is a positive feedback trend whereby increasing SF leads to an increase in the cold gas budget at average SF rates below 0.5 M yr −1 but above which becomes negative, where further increasing the SFR causes the cold gas budget to decrease. We have constructed an analytical model for this that reproduces the data well and could have profound implications for galaxy evolution in feedback-dominated regimes.

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Section: Introductionmentioning

confidence: 99%

Positive feedback at the disc-halo interface

Hobbs,

Feldmann

2020

Preprint

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Positive feedback at the disc–halo interface

Hobbs

Feldmann

2020

Monthly Notices of the Royal Astronomical Society

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The flat star formation (SF) history of the Milky Way (MW) requires gas in the Galactic disc to be replenished, most likely from a reservoir outside the Galaxy. Such a replenishment may be achieved by a form of ‘positive’ feedback, whereby SF feedback creates a Galactic fountain cycle that collects and cools additional gas from the hot halo surrounding the Galaxy. In this paper we present a model of this process for the MW. A section of the Galactic disc is allowed to form stars which subsequently explode as supernovae (SNe) and send gas out into the hot halo. The gas that is sent out is colder than the hot halo gas and, as it mixes, the halo gas is cooled, providing fuel for further SF as the mixture falls back onto the Galactic disc. We find that this process can be sufficient to maintain a roughly-constant cold gas mass in the MW over at least 3 Gyr. Our results further suggest that there is a positive feedback trend whereby increasing SF leads to an increase in the cold gas budget at average SF rates below 0.5 M⊙yr−1 and a negative feedback trend above this where further increasing the SFR leads to a decrease in the cold gas budget. We have constructed an analytical model for this that reproduces the data well and could have profound implications for galaxy evolution in feedback-dominated regimes.

show abstract

Molecular gas and dust in spiral galaxies

Cited by 2 publications

References 30 publications

Positive feedback at the disc-halo interface

Positive feedback at the disc-halo interface

Positive feedback at the disc–halo interface

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