The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
TLDR
In this article, an orbital model for the gas stream observed in the Central Molecular Zone (CMZ) is presented by integrating orbits in the empirically constrained gravitational potential and represents a good fit to the observed position-velocity distribution of dense (n > several 103 cm-3) gas, reproducing all of its key properties.Abstract:
We recently proposed that the star-forming potential of dense molecular clouds in the Central Molecular Zone (CMZ, i.e. the central few 100 pc) of the Milky Way is intimately linked to their orbital dynamics, potentially giving rise to an absolute-time sequence of star-forming clouds. In this paper, we present an orbital model for the gas stream(s) observed in the CMZ. The model is obtained by integrating orbits in the empirically constrained gravitational potential and represents a good fit (χ2red=2.0) to the observed position–velocity distribution of dense (n > several 103 cm-3) gas, reproducing all of its key properties. The orbit is also consistent with observational constraints not included in the fitting process, such as the 3D space velocities of Sgr B2 and the Arches and Quintuplet clusters. It differs from previous, parametric models in several respects: (1) the orbit is open rather than closed due to the extended mass distribution in the CMZ, (2) its orbital velocity (100–200 km s-1) is twice as high as in previous models, and (3) Sgr A* coincides with the focus of the (eccentric) orbit rather than being offset. Our orbital solution supports the recently proposed scenario in which the dust ridge between G0.253+0.016 (‘the Brick’) and Sgr B2 represents an absolute-time sequence of star-forming clouds, of which the condensation was triggered by the tidal compression during their most recent pericentre passage. We position the clouds on a common timeline and find that their pericentre passages occurred 0.30–0.74 Myr ago. Given their short free-fall times (tff ∼ 0.34 Myr), the quiescent cloud G0.253+0.016 and the vigorously star-forming complex Sgr B2 are separated by a single free-fall time of evolution, implying that star formation proceeds rapidly once collapse has been initiated. We provide the complete orbital solution, as well as several quantitative predictions of our model (e.g. proper motions and the positions of star formation ‘hotspots’). The paper is concluded with a discussion of the assumptions and possible caveats, as well as the position of the model in the Galactic context, highlighting its relation to large-scale gas accretion, the dynamics of the bar, the x2 orbital family, and the origin of the Arches and Quintuplet clusters.read more
Citations
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Journal ArticleDOI
Dense gas in the Galactic central molecular zone is warm and heated by turbulence
Adam Ginsburg,Christian Henkel,Christian Henkel,Yiping Ao,Denise Riquelme,Jens Kauffmann,Thushara Pillai,Elisabeth A. C. Mills,Miguel Angel Requena-Torres,K. Immer,Leonardo Testi,Juergen Ott,John Bally,Cara Battersby,Jeremy Darling,Susanne Aalto,Thomas Stanke,Sarah Kendrew,J. M. Diederik Kruijssen,Steven N. Longmore,James E. Dale,Rolf Guesten,Karl M. Menten +22 more
TL;DR: In this paper, the authors measured the temperature of the dense gas in the central molecular zone (CMZ) and examined what drives it, finding that the gas temperature is uniformly higher than the dust temperature, confirming that dust is a coolant in the densities.
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The lifecycle of molecular clouds in nearby star-forming disc galaxies
Mélanie Chevance,J. M. Diederik Kruijssen,Alexander P. S. Hygate,Alexander P. S. Hygate,Andreas Schruba,Steven N. Longmore,Brent Groves,Jonathan D. Henshaw,Cinthya N. Herrera,Annie Hughes,Annie Hughes,Sarah M R Jeffreson,Philipp Lang,Adam K. Leroy,Sharon Meidt,Jérôme Pety,Alessandro Razza,Alessandro Razza,Erik Rosolowsky,Eva Schinnerer,Frank Bigiel,Guillermo A. Blanc,Guillermo A. Blanc,Eric Emsellem,Eric Emsellem,Christopher M Faesi,Simon C. O. Glover,Daniel T. Haydon,I-Ting Ho,Kathryn Kreckel,Kathryn Kreckel,Janice C. Lee,Daizhong Liu,Miguel Querejeta,Miguel Querejeta,Toshiki Saito,Jiayi Sun,A. Usero,Dyas Utomo +38 more
TL;DR: German Research Foundation (DFG) and the European Research Council (ERC) as mentioned in this paper proposed a joint research cooperation scheme with the French National Cosmology et Galaxies (PNCG) of the Centre national de la recherche scientifique/Institut national de physique nucleaire et de physique des particules (IN2P3) of France.
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Molecular gas kinematics within the central 250 pc of the Milky Way
Jonathan D. Henshaw,Steven N. Longmore,J. M. D. Kruijssen,Ben Davies,John Bally,Ashley T. Barnes,Cara Battersby,Michael G. Burton,Maria Cunningham,James E. Dale,Adam Ginsburg,K. Immer,Paul A. Jones,Sarah Kendrew,Elisabeth A. C. Mills,Sergio Molinari,Toby J. T. Moore,J. Ott,Thushara Pillai,Jill Rathborne,Peter Schilke,Anika Schmiedeke,Leonardo Testi,Daniel Walker,Andrew Walsh,Qizhou Zhang +25 more
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Star formation rates and efficiencies in the Galactic Centre
Ashley T. Barnes,Steven N. Longmore,Cara Battersby,John Bally,J. M. D. Kruijssen,J. M. D. Kruijssen,Jonathan D. Henshaw,Daniel Walker +7 more
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Journal ArticleDOI
Fast and inefficient star formation due to short-lived molecular clouds and rapid feedback.
J. M. Diederik Kruijssen,J. M. Diederik Kruijssen,Andreas Schruba,Mélanie Chevance,Steven N. Longmore,Alexander P. S. Hygate,Alexander P. S. Hygate,Daniel T. Haydon,A. F. McLeod,A. F. McLeod,Julianne J. Dalcanton,Linda J. Tacconi,Ewine F. van Dishoeck,Ewine F. van Dishoeck +13 more
TL;DR: The findings reveal that galaxies consist of building blocks undergoing vigorous, feedback-driven life cycles that vary with the galactic environment and collectively define how galaxies form stars.
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