'The Brick' is not a brick: A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016

Abstract

In this paper we provide a comprehensive description of the internal dynamics of G0.253+0.016 (a.k.a. 'the Brick'); one of the most massive and dense molecular clouds in the Galaxy to lack signatures of widespread star formation. As a potential host to a future generation of high-mass stars, understanding largely quiescent molecular clouds like G0.253+0.016 is of critical importance. In this paper, we reanalyse Atacama Large Millimeter Array cycle 0 HNCO $J=4(0,4)-3(0,3)$ data at 3 mm, using two new pieces of software which we make available to the community. First, scousepy, a Python implementation of the spectral line fitting algorithm scouse. Secondly, acorns (Agglomerative Clustering for ORganising Nested Structures), a hierarchical n-dimensional clustering algorithm designed for use with discrete spectroscopic data. Together, these tools provide an unbiased measurement of the line of sight velocity dispersion in this cloud, ${\sigma }_{v_{los},1D}=4.4\pm 2.1$ kms${}^{-1}$, which is somewhat larger than predicted by velocity dispersion-size relations for the Central Molecular Zone (CMZ). The dispersion of centroid velocities in the plane of the sky are comparable, yielding ${\sigma }_{v_{los},1D}/{\sigma }_{v_{pos},1D}\sim 1.2\pm 0.3$. This isotropy may indicate that the line-of-sight extent of the cloud is approximately equivalent to that in the plane of the sky. Combining our kinematic decomposition with radiative transfer modelling we conclude that G0.253+0.016 is not a single, coherent, and centrally-condensed molecular cloud; 'the Brick' is not a \emph{brick}. Instead, G0.253+0.016 is a dynamically complex and hierarchically-structured molecular cloud whose morphology is consistent with the influence of the orbital dynamics and shear in the CMZ.

arXiv comment29 pages, 19 figures, 1 table (including appendix). Accepted for publication in MNRAS (February 4, 2019). Scousepy is available here: https://github.com/jdhenshaw/scousepy. Acorns is available here: https://github.com/jdhenshaw/acorns

References in corpus (103)

• Scikit-learn: Machine Learning in Python
• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• Cosmic Star Formation History
• A computer program for fast non-LTE analysis of interstellar line spectra
• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• A General Theory of Turbulence-Regulated Star Formation, From Spirals to ULIRGs
• Cold Dark Clouds: The Initial Conditions for Star Formation
• The Star Formation Rate of Turbulent Magnetized Clouds: Comparing Theory, Simulations, and Observations
• On the Star Formation Rates in Molecular Clouds
• The persistent cosmic web and its filamentary structure I: Theory and implementation
• Physical Conditions in Regions of Star Formation
• Structural Analysis of Molecular Clouds: Dendrograms
• The Star Formation Rate of Supersonic MHD Turbulence
• Cores, filaments, and bundles: hierarchical core formation in the L1495/B213 Taurus region
• HST/NICMOS Observations of Massive Stellar Clusters Near the Galactic Center
• Physical properties of molecular clouds for the entire Milky Way disk
• A 100-parsec elliptical and twisted ring of cold and dense molecular clouds revealed by Herschel around the Galactic Center
• Variations in the Galactic star formation rate and density thresholds for star formation
• Bias-free Measurement of Giant Molecular Cloud Properties
• One-Point Probability Distribution Functions of Supersonic Turbulent Flows in Self-Gravitating Media
• Star Formation Rates in Molecular Clouds and the Nature of the Extragalactic Scaling Relations
• On the universality of supersonic turbulence
• What controls star formation in the central 500 pc of the Galaxy?
• The persistent cosmic web and its filamentary structure II: Illustrations
• Analytical star formation rate from gravoturbulent fragmentation
• The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
• ATLASGAL --- towards a complete sample of massive star forming clumps
• Dense gas in the Galactic central molecular zone is warm and heated by turbulence
• Molecular gas kinematics within the central 250 pc of the Milky Way
• Formation of Massive Molecular Cloud Cores by Cloud-cloud Collision
• Star Formation in the Central 400 pc of the Milky Way: Evidence for a Population of Massive YSOs
• An uncertainty principle for star formation. I. Why galactic star formation relations break down below a certain spatial scale
• Spatially Resolved Chemistry in Nearby Galaxies I. The Center of IC 342
• The link between turbulence, magnetic fields, filaments, and star formation in the Central Molecular Zone cloud G0.253+0.016
• Hot and Diffuse Clouds near the Galactic Center Probed by Metastable H3+
• Star formation rates and efficiencies in the Galactic Centre
• Spectral imaging of the Central Molecular Zone in multiple 3-mm molecular lines
• MALT90: The Millimetre Astronomy Legacy Team 90 GHz Survey
• The thermal state of molecular clouds in the Galactic Center: evidence for non-photon-driven heating
• The Millimeter Astronomy Legacy Team 90 GHz (MALT90) Pilot Survey
• The interplay between a galactic bar and a supermassive black hole: nuclear fueling in a sub-parsec resolution galaxy simulation
• FellWalker - a Clump Identification Algorithm
• G0.253+0.016: a molecular cloud progenitor of an Arches-like cluster
• Candidate super star cluster progenitor gas clouds possibly triggered by close passage to Sgr A*
• A Dynamical Model for the Formation of Gas Rings and Episodic Starbursts Near Galactic Centres
• Comparing molecular gas across cosmic time-scales: the Milky Way as both a typical spiral galaxy and a high-redshift galaxy analogue
• Isolating signatures of major cloud-cloud collisions using position-velocity diagrams
• The linewidth-size relationship in the dense ISM of the Central Molecular Zone
• The Galactic Center Molecular Cloud Survey. I. A Steep Linewidth-Size Relation & Suppression of Star Formation
• The Origin of Diffuse X-ray and $\gamma$-ray Emission from the Galactic Center Region: Cosmic Ray Particles
• The XMM-Newton view of the central degrees of the Milky Way
• A Molecular Face-on View of the Galactic Centre Region
• A cluster in the making: ALMA reveals the initial conditions for high-mass cluster formation
• Turbulence sets the initial conditions for star formation in high-pressure environments
• Quantifying Observational Projection Effects Using Molecular Cloud Simulations
• A Dynamical Model for Gas Flows, Star Formation, and Nuclear Winds in Galactic Centres
• The Galactic Center Cloud G0.253+0.016: A Massive Dense Cloud with low Star Formation Potential
• Graph-based interpretation of the Molecular Interstellar Medium Segmentation
• Distributed star formation throughout the Galactic Center cloud Sgr B2
• Isolating signatures of major cloud-cloud collisions II: The lifetimes of broad bridge features
• HST Paschen-alpha Survey of the Galactic Center: Data Reduction and Products
• The Survey of Water and Ammonia in the Galactic Center (SWAG): Molecular Cloud Evolution in the Central Molecular Zone
• Mass inflow rate into the Central Molecular Zone: observational determination and evidence of episodic accretion
• Near-infrared counterparts to Chandra X-ray sources toward the Galactic Center. II. Discovery of Wolf-Rayet stars and O supergiants
• The dynamical evolution of molecular clouds near the Galactic Centre - II. Spatial structure and kinematics of simulated clouds
• A theoretical explanation for the Central Molecular Zone asymmetry
• Infall Signatures in a Prestellar Core embedded in the High-Mass 70 $\mu$m Dark IRDC G331.372-00.116
• There are no starless massive proto-clusters in the first quadrant of the Galaxy
• Search for starless clumps in the ATLASGAL survey
• Synthetic C${}^{18}$O observations of fibrous filaments: the problems of mapping from PPV to PPP
• G0.253+0.016: A centrally condensed, high-mass protocluster
• A general theory for the lifetimes of giant molecular clouds under the influence of galactic dynamics
• Detection of Widespread Hot Ammonia in the Galactic Center
• Velocity Field Statistics in Star-Forming Regions. I. Centroid Velocity Observations
• Line Profiles of Cores within Clusters: I. The Anatomy of a Filament
• Seeding the Galactic Centre gas stream: gravitational instabilities set the initial conditions for the formation of protocluster clouds
• The dynamics and star-forming potential of the massive Galactic centre cloud G0.253+0.016
• On the temperature structure of the Galactic Centre cloud G0.253+0.016
• A multi-wavelength view of the Galactic center dust ridge reveals little star formation
• Nuclear Spirals in the inner Milky Way
• Abundant Methanol Masers but no New Evidence for Star Formation in GCM0.253+0.016
• The Dense Gas Fraction in Galactic Center Clouds
• Star Formation Rates of Massive Molecular Clouds in the Central Molecular Zone
• ATCA Survey of Ammonia in the Galactic Center: The Temperatures of Dense Gas Clumps between SgrA* and SgrB2
• Star formation in a high-pressure environment: An SMA view of the Galactic centre dust ridge
• G11.92-0.61-MM2: A Bonafide Massive Prestellar Core?
• The Galactic Center Molecular Cloud Survey. II. A Lack of Dense Gas & Cloud Evolution along Galactic Center Orbits
• Main-sequence stars masquerading as Young Stellar Objects in the central molecular zone
• Early stage massive star formation near the Galactic Center: Sgr C
• H2O Southern Galactic Plane Survey (HOPS): Paper III - Properties of Dense Molecular Gas across the Inner Milky Way
• Three-dimensional molecular line transfer: A simulated star-forming region
• On the physical mechanisms governing the cloud lifecycle in the Central Molecular Zone of the Milky Way
• ALMA view of G0.253+0.016: Can cloud-cloud collision form the cloud?
• Star formation in the massive "starless" infrared dark cloud G0.253$+$0.016
• XMM-Newton study of the persistent X-ray source 1E1743.1-2843 located in the Galactic Center direction
• A Catalog of 24um Sources Toward the Galactic Center
• The Carina Flare: What can fragments in the wall tell us?
• Spitzer Infrared Spectrograph Observations of the Galactic Center: Quantifying the Extreme Ultraviolet/so ft X-ray fluxes
• Evidence that widespread star formation may be underway in G0.253+016, "The Brick"
• Absorption Filaments Towards the Massive Clump G0.253+0.016
• The CARMA 3mm Survey of the Inner $0.7^{\circ }\times 0.4^{\circ }$ of the Central Molecular Zone
• A Brief Update on the CMZoom Survey

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• WISDOM Project -- IX Giant Molecular Clouds in the Lenticular Galaxy NGC4429: Effects of Shear and Tidal Forces on Clouds
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• Star formation in 'the Brick': ALMA reveals an active proto-cluster in the Galactic centre cloud G0.253+0.016
• The core population and kinematics of a massive clump at early stages: an ALMA view
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• ALMA Observations of Massive Clouds in the Central Molecular Zone: Ubiquitous Protostellar Outflows
• The Atacama Cosmology Telescope: Microwave Intensity and Polarization Maps of the Galactic Center
• CMZoom II: Catalog of Compact Submillimeter Dust Continuum Sources in the Milky Way's Central Molecular Zone
• The centres of M83 and the Milky Way: opposite extremes of a common star formation cycle
• Autonomous Gaussian decomposition of the Galactic Ring Survey. I. Global statistics and properties of the 13CO emission data
• Hierarchical Clustering in Astronomy
• PHANGS-JWST First Results: Stellar Feedback-Driven Excitation and Dissociation of Molecular Gas in the Starburst Ring of NGC 1365?
• SOFIA/HAWC+ Far-Infrared Polarimetric Large-Area CMZ Exploration (FIREPLACE) Survey III: Full Survey Data Set
• GMC Collisions as Triggers of Star Formation. VII. The Effect of Magnetic Field Strength on Star Formation
• A global view on star formation: The GLOSTAR Galactic plane survey IV. Radio continuum detections of young stellar objects in the Galactic Centre region
• Velocity Gradients: Magnetic Field Tomography towards the Supernova Remnant W44
• Decomposing Magnetic Fields in Three Dimensions over the Central Molecular Zone
• ALMA-IMF XIII: N${}_2$H${}^{+}$ kinematic analysis on the intermediate protocluster G353.41
• WISDOM Project XII. Clump properties and turbulence regulated by clump-clump collisions in the dwarf galaxy NGC404
• Formation of hub-filament structure triggered by cloud-cloud collision in W33 complex
• A wind-blown bubble in the Central Molecular Zone cloud G0.253+0.016
• Fiery Cores: Bursty and Smooth Star Formation Distributions across Galaxy Centers in Cosmological Zoom-in Simulations
• Virial Clumps in Central Molecular Zone Clouds
• Atacama Large Aperture Submillimeter Telescope (AtLAST) Science: Our Galaxy
• SRG/eROSITA view of X-ray reflection in the Central Molecular Zone: a snapshot in September-October 2019
• Distance to the Brick cloud using stellar kinematics
• A new distance to the Brick, the dense molecular cloud G0.253+0.016
• JWST reveals widespread CO ice and gas absorption in the Galactic Center cloud G0.253+0.016
• Revealing Gas Inflows towards the Galactic Central Molecular Zone
• Kinematics of Galactic Centre clouds shaped by shear-seeded solenoidal turbulence
• The initial conditions for young massive cluster formation in the Galactic Centre: convergence of large-scale gas flows
• AMOEBA: Automated Molecular Excitation Bayesian Line-Fitting Algorithm
• JWST-ALMA Study of a Hub-Filament System in the Nascent Phase
• CMZoom III: Spectral Line Data Release
• A probable Keplerian disk feeding an optically revealed massive young star
• HCN $J$=4-3, HNC $J$=1-0, ${\mathrm{H}}^{13}\mathrm{CN}$ $J$=1-0, and $\mathrm{H}{\mathrm{C}}_3\mathrm{N}$ $J$=10-9 Maps of Galactic Center Region II.: Physical Properties of Dense Gas Clumps and Probability of Star Formation
• Interaction between the Supernova Remnant W44 and the Infrared Dark Cloud G034.77-00.55: shock induced star formation?
• Autonomous Gaussian decomposition of the Galactic Ring Survey. II. The Galactic distribution of 13CO
• The magnetic field in the Flame nebula
• Turbulent Pressure Heats Gas and Suppresses Star Formation in Galactic Bar Molecular Clouds
• Gas Transfer Between the Inner 3-kpc Disk and the Galactic Central Molecular Zone
• The complex multi-scale structure in simulated and observed emission maps of the proto-cluster cloud G0.253+0.016 (`the Brick')
• ArTéMiS imaging of the filamentary infrared dark clouds G1.75-0.08 and G11.36+0.80: Dust-based physical properties of the clouds and their clumps
• Molecular cloud matching in CO and dust in M33 II. Physical properties of giant molecular clouds
• CO Structures with Narrow Lines in Nearby Quiescent Regions
• The Complex Magnetic Field of the Extreme Galactic Center: PRIMA Science Potential
• Self-consistent modelling of the Milky Way's Nuclear Stellar Disc