Stellar cluster formation in a Milky Way-sized galaxy at z>4 -- I. The proto-globular cluster population and the imposter amongst us

Abstract

The formation history of globular clusters (GCs) at redshift $z>4$ remains an unsolved problem. In this work, we use the cosmological, $N$-body hydrodynamical ``zoom-in'' simulation GigaEris to study the properties and formation of proto-GC candidates in the region surrounding the progenitor of a Milky Way-sized galaxy. The simulation employs a modern implementation of smoothed-particle hydrodynamics, including metal-line cooling and metal and thermal diffusion and allows to resolve systems at the scale of star clusters. We define proto-GC candidate systems as gravitationally bound stellar systems with baryonic mass fraction $F_{\mathrm{b}}\ge 0.75$ and stellar velocity dispersion ${\sigma }_{\star }<20$ km s${}^{-1}$. At $z=4.4$ we identify 9 systems which satisfy our criteria, all of which form between 10 kpc to 30 kpc from the centre of the main host. Their baryonic masses are in the range $10^5$- $10^7$ M${}_{\odot }$. By the end of the simulation, they still have a relatively low stellar mass ($M_{\star }\sim 10^4$--$10^5$ M${}_{\odot }$) and a metallicity ($-1.8\lesssim [Fe/H]\lesssim -0.8$) similar to the blue Galactic GCs. All of the identified systems except one appear to be associated with gas filaments accreting onto the main galaxy in the circum-galactic region, and formed at $z=5-4$. The exception is the oldest object, which appears to be a stripped compact dwarf galaxy that has interacted with the main halo between $z=5.8$ and $z=5.2$ and has lost its entire dark matter content due to tidal mass loss.

11 pages, 8 figures, accepted for publication in MNRAS

References in corpus (28)

• Star Formation and Feedback in Smoothed Particle Hydrodynamic Simulations--I. Isolated Galaxies
• Gaia EDR3 view on Galactic globular clusters
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• Paving the way for the JWST: witnessing globular cluster formation at z>3
• STARFORGE: Toward a comprehensive numerical model of star cluster formation and feedback
• VINTERGATAN I: The origins of chemically, kinematically and structurally distinct discs in a simulated Milky Way-mass galaxy
• Resolved spectroscopy of gravitationally lensed galaxies: global dynamics and star-forming clumps on ~100pc scales
• The Nature of UCDs: Internal Dynamics from an Expanded Sample and Homogeneous Database
• Star cluster formation in cosmological simulations. I. Properties of young clusters
• The origin of the Milky Way globular clusters
• High star cluster formation efficiency in the strongly lensed Sunburst Lyman-continuum galaxy at z=2.37
• A Common Origin for Globular Clusters and Ultra-faint Dwarfs in Simulations of the First Galaxies
• Early results from GLASS-JWST. VII: evidence for lensed, gravitationally bound proto-globular clusters at z=4 in the Hubble Frontier Field A2744
• Co-formation of the thin and thick discs revealed by APOGEE-DR16 and Gaia-DR2
• Introducing EMP-Pathfinder: modelling the simultaneous formation and evolution of stellar clusters in their host galaxies
• Formation and evolution of young massive clusters in galaxy mergers: the SMUGGLE view
• On the origin of surprisingly cold gas discs in galaxies at high redshift
• Great Balls of FIRE I: The formation of star clusters across cosmic time in a Milky Way-mass galaxy
• Globular cluster systems and galaxy formation
• Where did the globular clusters of the Milky Way form? Insights from the E-MOSAICS simulations
• From giant clumps to clouds -- II. The emergence of thick disc kinematics from the conditions of star formation in high redshift gas rich galaxies
• The effect of non-equilibrium metal cooling on the interstellar medium
• Star Formation at z=2.481 in the Lensed Galaxy SDSS J1110+6459, II: What is missed at the normal resolution of the Hubble Space Telescope?
• The Dawn of Disk Formation in a Milky Way-sized Galaxy Halo: Thin Stellar Disks at $z>4$
• Search Instructions for Globular Clusters in Formation at High Redshifts
• Constraints on the [CII] luminosity of a proto-globular cluster at z~6 obtained with ALMA
• Little Blue Dots in the Hubble Space Telescope Frontier Fields: Precursors to Globular Clusters?
• Stellar cluster formation in a Milky Way-sized galaxy at z>4 -- II. A hybrid formation scenario for the nuclear star cluster and its connection to the nuclear stellar ring

Cited by in corpus (7)

• Gravitational waves from mergers of Population III binary black holes: roles played by two evolution channels
• Smooth kinematic and metallicity gradients reveal that the Milky Way's nuclear star cluster and disc might be part of the same structure
• Globular cluster ages and their relation to high-redshift stellar cluster formation times from different globular cluster models
• MOCCA: Effects of pristine gas accretion and cluster migration on globular cluster evolution, global parameters, and multiple stellar populations
• Cosmological insights into the early accretion of r-process-enhanced stars II. Dynamical identification of lost members of Reticulum II
• Cosmic wallflowers: the circumgalactic origins of isolated ultra-compact star clusters at $z>7$
• On the Jeans criterion for hydrostatic and infalling gas