ALMA-IMF XVIII: The assembly of a star cluster: Dense N${}_2$H${}^{+}$ (1-0) kinematics in the massive G351.77 protocluster

Abstract

ALMA-IMF observed 15 massive protoclusters capturing multiple spectral lines and the continuum emission. We focus on the G351.77 protocluster ($\sim$ 2500 M${}_{\odot }$, estimated from single-dish continuum observations) located at 2 kpc. We trace the dense gas emission and kinematics with N${}_2$H${}^{+}$ (1-0) at $\sim$ 4 kau resolution. We estimate an N${}_2$H${}^{+}$ relative abundance $\sim (1.7\pm 0.5)\times 10^{-10}$. We decompose the N${}_2$H${}^{+}$ emission into up to two velocity components, highlighting the kinematic complexity in the dense gas. By examining the position-velocity (PV) diagrams on small scales, we observe clear inflow signatures (V-shapes) associated with dense cores. The most prominent V-shape has a mass inflow rate of $\sim 13.5\times 10^{-4}$ M${}_{\odot }$ yr${}^{-1}$ and a short timescale of $\sim$ 11.4 kyr. We also observe V-shapes without associated cores. This suggests both that cores or centers of accretion exist below the 1.3 mm detection limit, and that the V-shapes may be viable tracers of very early accretion and star formation on $\sim$ 4 kau scales. The large-scale PV diagram shows that the protocluster is separated into 2 principal velocity structures. Combined with smaller scale DCN and H${}_2$CO emission, we propose a scenario of larger scale slow contraction with rotation in the center based on simple toy models. This scenario leads the suggestion of outside-in evolution of the protocluster as it collapses. The gas depletion times implied by the V-shapes are short ($\sim$ 0.3 Myr), requiring either very fast cluster formation, and/or continuous mass feeding of the protocluster. The latter is possible via the Mother Filament G351.77 is forming out of. The similarities in the properties of G351.77 and the recently published work in G353.41 indicate that many of the physical conditions inferred via the ALMA-IMF N${}_2$H${}^{+}$ observations may be generic to protoclusters.

arXiv commentAccepted for A&A, 29 pages, 31 figures, 4 interactive figures, 7 tables

References in corpus (96)

• Embedded Clusters in Molecular Clouds
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• High-Mass Star and Massive Cluster Formation in the Milky Way
• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• Molecular ions in L1544. II. The ionization degree
• Global Hierarchical Collapse In Molecular Clouds. Towards a Comprehensive Scenario
• Dynamic star formation in the massive DR21 filament
• The initial conditions of stellar protocluster formation. I. A catalogue of Spitzer dark clouds
• Molecular Inventories and Chemical Evolution of Low-mass Protostellar Envelopes
• Before the first supernova: combined effects of HII regions and winds on molecular clouds
• Chemistry in Infrared Dark Cloud Clumps: a Molecular Line Survey at 3 mm
• The anatomy of the Orion B Giant Molecular Cloud: A local template for studies of nearby galaxies
• Dense core formation by fragmentation of velocity-coherent filaments in L1517
• Molecular ions in L1544. I. Kinematics
• Molecular Excitation and Differential Gas-Phase Depletions in the IC 5146 Dark Cloud
• The H2CO abundance in the inner warm regions of low mass protostellar envelopes
• The dynamical properties of dense filaments in the infrared dark cloud G035.39-00.33
• Evolution of column density distributions within Orion~A
• Slingshot Mechanism in Orion: Kinematic Evidence For Ejection of Protostars by Filaments
• Filamentary Fragmentation and Accretion in High-Mass Star-Forming Molecular Clouds
• Gravitational collapse of the OMC-1 region
• From the Convergence of Filaments to Disk-Outflow Accretion: Massive-Star Formation in W33A
• CARMA Large Area Star Formation Survey: Observational Analysis of Filaments in the Serpens South Molecular Cloud
• Robustness of N2H+ as tracer of the CO snowline
• Isolating signatures of major cloud-cloud collisions II: The lifetimes of broad bridge features
• Filamentary Accretion Flows in the Infrared Dark Cloud G14.225-0.506 Revealed by ALMA
• Gravity Driven Magnetic Field at ~1000 au Scales in High-mass Star Formation
• pyspeckit: A spectroscopic analysis and plotting package
• ALMA-IMF I -- Investigating the origin of stellar masses: Introduction to the Large Program and first results
• Complex Structure in Class 0 Protostellar Envelopes III: Velocity Gradients in Non-Axisymmetric Envelopes, Infall or Rotation?
• Searching for massive pre--stellar cores through observations of N2H+ and N2D+
• ALMA resolves the spiraling accretion flow in the luminous OB cluster forming region G33.92+0.11
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XI. From inflow to infall in hub-filament systems
• Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N
• Multiscale, multiwavelength extraction of sources and filaments using separation of the structural components: getsf
• High sensitivity maps of molecular ions in L1544: I. Deuteration of N2H+ and HCO+ and first evidence of N2D+ depletion
• Distribution of Serpens South protostars revealed with ALMA
• The role of molecular filaments in the origin of the prestellar core mass function and stellar initial mass function
• CARMA Large Area Star Formation Survey: Structure and Kinematics of Dense Gas in Serpens Main
• N2H+ and HC3N Observations of the Orion A Cloud
• Gas-phase CO depletion and N2H+ abundances in starless cores
• Resolved Depletion Zones and Spatial Differentiation of N2H+ and N2D+
• Formation of proto-cluster: a virialized structure from gravo-turbulent collapse I. Simulation of cluster formation in collapsing molecular cloud
• Tracing extended low-velocity shocks through SiO emission - Case study of the W43-MM1 ridge
• Evidence of high-mass star formation through multi-scale mass accretion in hub-filament-system clouds
• Radiative transfer modelling of W33A MM1: 3-D structure and dynamics of a complex massive star forming region
• ALMA-IMF. V. Prestellar and protostellar core populations in the W43 cloud complex
• Formation of the Musca filament: Evidence for asymmetries in the accretion flow due to a cloud-cloud collision
• N2H+ depletion in the massive protostellar cluster AFGL 5142
• Large-scale periodic velocity oscillation in the filamentary cloud G350.54+0.69
• Properties and rotation of molecular clouds in M 33
• CARMA Large Area Star Formation Survey: Project Overview with Analysis of Dense Gas Structure and Kinematics in Barnard 1
• Slingshot Mechanism for Clusters: Gas Density Regulates Star Density in the Orion Nebula Cluster (M42)
• ALMA-IMF VI -- Investigating the origin of stellar masses: Core mass function evolution in the W43-MM2&MM3 mini-starburst
• On the kinematics of massive star forming regions: the case of IRAS 17233-3606
• Fragmentation and disk formation in high-mass star formation: The ALMA view of G351.77-0.54 at 0.06" resolution
• Direct observational evidence of the multi-scale, dynamical mass accretion toward a high-mass star forming hub-filament system
• ALMA-IMF II -- investigating the origin of stellar masses: Continuum Images and Data Processing
• The core population and kinematics of a massive clump at early stages: an ALMA view
• Evidence of a SiO collimated outflow from a massive YSO in IRAS 17233-3606
• ALMA-IMF XV: The core mass function in the high-mass star-formation regime
• Multi-scale analysis of the Monoceros OB 1 star-forming region: II. Colliding filaments in the Monoceros OB1 molecular cloud
• On the size of the CO-depletion radius in the IRDC G351.77-0.51
• Rotation of molecular clouds in M~51
• Gas velocity structure of the Orion A Integral Shaped Filament
• Unveiling a Compact Cluster of Massive and Young Stars in IRAS 17233-3606
• Filament rotation in the California L1482 cloud
• ALMA-IMF XI: The sample of hot core candidates A rich population of young high-mass proto-stars unveiled by the emission of methyl formate
• The molecular distribution of the IRDC G351.77-0.51
• Non-adiabatic turbulence driving during gravitational collapse
• ALMA-IMF. VII. First release of the full spectral line cubes: Core kinematics traced by DCN J=(3-2)
• High mass star formation in the IRAS 17233-3606 region: a new nearby and bright hot core in the southern sky
• ALMA-IMF IV -- A comparative study of the main hot cores in W43-MM1: detection, temperature and molecular composition
• Water emission from the high-mass star-forming region IRAS 17233-3606. High water abundances at high velocities
• ALMA-IMF X -- The core population in the evolved W33-Main (G012.80) protocluster
• Insights on the Sun birth environment in the context of star-cluster formation in hub-filament systems
• ALMA-IMF XIII: N${}_2$H${}^{+}$ kinematic analysis on the intermediate protocluster G353.41
• Multiscale Dynamical Scenario of High-mass Star Formation in an IRDC Filament G34
• Characterising the high-mass star forming filament G351.776--0.527 with Herschel and APEX dust continuum and gas observations
• Emergence of high-mass stars in complex fiber networks (EMERGE). I. Early ALMA Survey: observations and massive data reduction
• Role of Filamentary Structures in the Formation of Two Dense Cores, L1544 and L694-2
• ALMA-IMF XVI: Mass-averaged temperature of cores and protostellar luminosities in the ALMA-IMF protoclusters
• The SiO outflow from IRAS 17233-3603 at high resolution
• ALMA-IMF XVII -- Census and lifetime of high-mass prestellar cores in 14 massive protoclusters
• G133.50+9.01: A likely cloud-cloud collision complex triggering the formation of filaments, cores and a stellar cluster
• Properties of the dense cores and filamentary structures in the Vela C molecular cloud
• Benchmarking the IRDC G351.77-0.53: Gaia DR3 distance, mass distribution, and star formation content
• Chemical evolution of N2H+ in six massive star-forming regions
• Line Ratios Reveal N2H+ Emission Originates Above the Midplane in TW Hydrae
• Synthetic Observations of the Infalling Rotating Envelope: Links between the Physical Structure and Observational Features
• Assessing the accuracy of the star formation rate measurements by direct star count in molecular clouds
• Filament Formation via Collision-induced Magnetic Reconnection -- Formation of a Star Cluster
• Physical Properties and Kinematics of Dense Cores Associated with Regions of Massive Star Formation from the Southern Sky
• The role of magnetic fields in the fragmentation of the Taurus B213 filament into Sun-type star-forming cores