Rapid build-up of the stellar content in the protocluster core SPT2349$-$56 at $z=4.3$

Abstract

The protocluster SPT2349$-$56 at $z=4.3$ contains one of the most actively star-forming cores known, yet constraints on the total stellar mass of this system are highly uncertain. We have therefore carried out deep optical and infrared observations of this system, probing rest-frame ultraviolet to infrared wavelengths. Using the positions of the spectroscopically-confirmed protocluster members, we identify counterparts and perform detailed source deblending, allowing us to fit spectral energy distributions in order to estimate stellar masses. We show that the galaxies in SPT2349$-$56 have stellar masses proportional to their high star-formation rates, consistent with other protocluster galaxies and field submillimetre galaxies (SMGs) around redshift 4. The galaxies in SPT2349$-$56 have on average lower molecular gas-to-stellar mass fractions and depletion timescales than field SMGs, although with considerable scatter. We construct the stellar-mass function for SPT2349$-$56 and compare it to the stellar-mass function of $z=1$ galaxy clusters, finding consistent shapes between the two. We measure rest-frame galaxy ultraviolet half-light radii from our HST-F160W imaging, finding that on average the galaxies in our sample are similar in size to typical star-forming galaxies at these redshifts. However, the brightest HST-detected galaxy in our sample, found near the luminosity-weighted centre of the protocluster core, remains unresolved at this wavelength. Hydrodynamical simulations predict that the core galaxies will quickly merge into a brightest cluster galaxy, thus our observations provide a direct view of the early formation mechanisms of this class of object.

Submitted to MNRAS Sept. 3, 2021 Accepted by MNRAS Dec, 4, 2021

References in corpus (43)

• The hierarchical formation of the brightest cluster galaxies
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• The MUSE second-generation VLT instrument
• The Herschel view of the dominant mode of galaxy growth from z=4 to the present day
• Galaxy Clusters Discovered via the Sunyaev-Zel'dovich Effect in the 2500-square-degree SPT-SZ survey
• From rings to bulges: evidence for rapid secular galaxy evolution at z~2 from integral field spectroscopy in the SINS survey
• An ALMA survey of Sub-millimeter Galaxies in the Extended Chandra Deep Field South: Physical properties derived from ultraviolet-to-radio modelling
• The Detection of a Population of Submillimeter-Bright, Strongly-Lensed Galaxies
• The SCUBA HAlf Degree Extragalactic Survey (SHADES) - III. Identification of radio and mid-infrared counterparts to submillimetre galaxies
• The Large APEX Bolometer Camera LABOCA
• The SCUBA-2 Cosmology Legacy Survey: ALMA resolves the rest-frame far-infrared emission of sub-millimeter galaxies
• Submillimetre galaxies in a hierarchical universe: number counts, redshift distribution, and implications for the IMF
• An excess of dusty starbursts related to the Spiderweb galaxy
• Sub-kpc ALMA imaging of compact star-forming galaxies at z~2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies
• The Rest-Frame Submillimeter Spectrum of High-Redshift, Dusty, Star-Forming Galaxies
• ALMA observations of atomic carbon in z~4 dusty star-forming galaxies
• How to distinguish starbursts and quiescently star-forming galaxies: The `bimodal' submillimetre galaxy population as a case study
• An ALMA survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS field: High-resolution dust continuum morphologies and the link between sub-millimetre galaxies and spheroid formation
• Spatial correlation between submillimetre and Lyman-alpha galaxies in the SSA 22 protocluster
• An ALMA/NOEMA survey of the molecular gas properties of high-redshift star-forming galaxies
• The ALPINE-ALMA [CII] Survey: Obscured Star Formation Rate Density and Main Sequence of star-forming galaxies at z>4
• Predictions for the spatial distribution of the dust continuum emission in 1<z<5 star-forming galaxies
• ALMA Observations of Gas-Rich Galaxies in z~1.6 Galaxy Clusters: Evidence for Higher Gas Fractions in High-Density Environments
• T-PHOT version 2.0: improved algorithms for background subtraction, local convolution, kernel registration, and new options
• The evolution of submillimetre galaxies: two populations and a redshift cut-off
• Revealing the Stellar Mass and Dust Distributions of Submillimeter Galaxies at Redshift 2
• Environmental impacts on molecular gas in protocluster galaxies at z~2
• HST/WFC3 grism observations of $z\sim 1$ clusters: The cluster vs. field stellar mass-size relation and evidence for size growth of quiescent galaxies from minor mergers
• Comprehensive Gas Characterization of a $z=2.5$ Protocluster: A Cluster Core Caught in the Beginning of Virialization?
• Clocking the formation of today's largest galaxies: Wide field integral spectroscopy of Brightest Cluster Galaxies and their surroundings
• Candidate high-z proto-clusters among the Planck compact sources, as revealed by Herschel-SPIRE
• FLAMINGOS-2: The Facility Near-Infrared Wide-field Imager & Multi-Object Spectrograph for Gemini
• Is there enough star formation in simulated protoclusters?
• A Planck-selected dusty proto-cluster at z=2.16 associated with a strong over-density of massive H$\alpha$ emitting galaxies
• Overdensities of Submillimetre-Bright Sources around Candidate Protocluster Cores Selected from the South Pole Telescope Survey
• Unbiased Differential Size Evolution and the Inside-Out Growth of Galaxies in the Deep CANDELS GOODS Fields at $1\le z\le 7$
• Ongoing growth of the brightest cluster galaxies via major dry mergers in the last ~6 Gyr
• Optical and near-infrared observations of the SPT2349-56 proto-cluster core at z = 4.3
• CO interferometry of gas-rich spiral galaxies in the outskirts of an intermediate redshift cluster
• The Inside-out Growth of the Most Massive Galaxies at 0.3<z<0.9
• Measuring the total infrared light from galaxy clusters at z=0.5-1.6: connecting stellar populations to dusty star formation
• SEEDisCS I. Molecular gas in galaxy clusters and their large scale structure: the case of CL1411.1$-$1148 at $z\sim 0.5$

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• The VIMOS Ultra Deep Survey: The reversal of the star-formation rate $-$ density relation at $2<z<5$
• Fast SMBH growth in the SPT2349--56 protocluster at $z=4.3$
• Noema formIng Cluster survEy (NICE): Discovery of a starbursting galaxy group with a radio-luminous core at z=3.95
• The Manhattan Suite: Accelerated galaxy evolution in the early Universe
• JWST's first glimpse of a z > 2 forming cluster reveals a top-heavy stellar mass function
• Discovering Large-Scale Structure at $2<z<5$ in the C3VO Survey
• Kinematic analysis of $\mathbf{z}=4.3$ galaxies in the SPT2349$-$56 protocluster core
• COALAS III: The ATCA CO(1-0) look at the growth and death of H$\alpha$ emitters in the Spiderweb protocluster at z=2.16
• Revealing the hidden cosmic feast: A z=4.3 galaxy group hosting two optically dark, efficiently star-forming galaxies
• A Large Molecular Gas Reservoir in the Protocluster SPT2349$-$56 at $z=4.3$
• Evidence for environmental effects in the $z=4.3$ protocluster core SPT2349$-$56
• A large thermal energy reservoir in the nascent intracluster medium at a redshift of 4.3
• Tracing the Total Stellar Mass and Star Formation of High-Redshift Protoclusters
• Bright [CII]158$\mu$m Streamers as a Beacon for Giant Galaxy Formation in SPT2349$-$56 at $z=4.3$
• Noema formIng Cluster survEy (NICE): A Census of Star Formation and Cold Gas Properties in Massive protoclusters at 1.5<z<4