Two Channels of Metal-Rich Compact Stellar System Formation: Starbursts under High Ram Pressure versus Tidal Stripping

Abstract

Most galaxies follow well-defined scaling relations of metallicity and stellar mass; however, some outliers at the low mass end of the observed galaxy population exhibit unusually high metallicity for their mass. Understanding how these objects get to be so metal-rich is vital for understanding the role of feedback in galaxy formation. Using the TNG50 simulation, we explore the origins of this phenomenon. We identify 227 metal-rich, compact stellar systems (CSSs) that deviate significantly from this scaling relation. These CSSs are satellites located in the vicinity of massive host galaxies, with stellar masses ranging from $10^8{M}_{\odot }$ to $10^{10}{M}_{\odot }$ (including six systems that are close analogs of the M31-M32 system). Contrary to the previously assumed scenario that such objects are predominantly products of tidal stripping, our results suggest a more prevalent role for ram pressure in their formation. Indeed, 76% (173) of these CSSs are formed through a burst of star formation occurring around the time of the first pericentric passage, typically at redshifts $z\lesssim 1$, aided by strong ram pressure and tidal forces. The high ram pressure, resulting from the CSSs' rapid motion near the halo center, facilitates metal enrichment, producing high-metallicity CSSs by confining the metal-rich gas from bursty star formation, which leads to distinct stellar populations characterized by enhanced metallicity as well as high $\alpha$-abundance. Only the remaining 24% (54) of metal-rich CSSs are generated through the tidal stripping of massive progenitors. Our results further indicate that M32 is more likely to have formed through intense star formation events rather than through gradual, tidal stripping, thereby providing crucial insights into the nature of low mass, compact galaxy formation.

arXiv comment20 pages, 12 figures, published in ApJ Letters

References in corpus (91)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Planck 2015 results. XIII. Cosmological parameters
• The chemical composition of the Sun
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• Populating a cluster of galaxies - I. Results at z=0
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Cosmological SPH simulations: A hybrid multi-phase model for star formation
• Simulating Galaxy Formation with the IllustrisTNG Model
• First results from the IllustrisTNG simulations: matter and galaxy clustering
• First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies
• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• First results from the IllustrisTNG simulations: A tale of two elements -- chemical evolution of magnesium and europium
• Simulating galaxy formation with black hole driven thermal and kinetic feedback
• A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
• The ages and metallicities of galaxies in the local universe
• First results from the IllustrisTNG simulations: radio haloes and magnetic fields
• First Results from the TNG50 Simulation: Galactic outflows driven by supernovae and black hole feedback
• First Results from the TNG50 Simulation: The evolution of stellar and gaseous disks across cosmic time
• How supernova feedback turns dark matter cusps into cores
• The Universal Stellar Mass-Stellar Metallicity Relation for Dwarf Galaxies
• The merger rate of galaxies in the Illustris Simulation: a comparison with observations and semi-empirical models
• The Cores of Dwarf Galaxy Halos
• Strangulation as the primary mechanism for shutting down star formation in galaxies
• A giant stream of metal-rich stars in the halo of the galaxy M31
• The Atlas3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies
• Evidence for Stellar Substructure in the Halo and Outer Disk of M31
• Mass loss from dwarf spheroidal galaxies: the origins of shallow dark matter cores and exponential surface brightness profiles
• The Haunted Halos of Andromeda and Triangulum: A panorama of galaxy formation in action
• The ACS Virgo Cluster Survey. VII. Resolving the Connection Between Globular Clusters and Ultra-Compact Dwarf Galaxies
• (Star)bursts of FIRE: observational signatures of bursty star formation in galaxies
• Global Relationships Among the Physical Properties of Stellar Systems
• The long bar as seen by the VVV survey: I. Colour-magnitude diagrams
• Stellar mass map and dark matter distribution in M31
• The Luminosity Profile and Structural Parameters of the Andromeda Galaxy
• SDSSJ150634.27+013331.6: the second compact elliptical galaxy in the NGC5846 group
• The Relationships Among Compact Stellar Systems: A Fresh View of Ultra Compact Dwarfs
• Simulating galaxies in the reionization era with FIRE-2: galaxy scaling relations, stellar mass functions, and luminosity functions
• The abundance, distribution, and physical nature of highly ionized oxygen OVI, OVII, and OVIII in IllustrisTNG
• The AIMSS Project I: Bridging the Star Cluster - Galaxy Divide
• Galaxy threshing and the formation of ultra-compact dwarf galaxies
• Multi-stage Three Dimensional Sweeping and Annealing of Disc Galaxies in Clusters
• Families of dynamically hot stellar systems over ten orders of magnitude in mass
• On the influence of ram-pressure stripping on the star formation of simulated spiral galaxies
• Jellyfish galaxies with the IllustrisTNG simulations: I. Gas-stripping phenomena in the full cosmological context
• Local Group Dwarf Spheroidals: Correlated Deviations from the Baryonic Tully-Fisher Relation
• The Andromeda galaxy's most important merger about 2 billion years ago as M32's likely progenitor
• Evidence for an outer disk in the Prototype `Compact Elliptical' Galaxy M32
• Global Properties of M31's Stellar Halo from the SPLASH Survey. I. Surface Brightness Profile
• A Population of Compact Elliptical Galaxies Detected with the Virtual Observatory
• Efficient early stellar feedback can suppress galactic outflows by reducing supernova clustering
• Colours, Star formation Rates, and Environments of Star forming and Quiescent Galaxies at the Cosmic Noon
• Discovery of Ultra-Compact Dwarf Galaxies in the Virgo Cluster
• The early-type dwarf galaxy population of the Hydra I cluster
• On DDO154 and Cold Dark Matter halo profiles
• The HST/ACS Coma Cluster Survey: V - Compact Stellar Systems in the Coma Cluster
• Galaxy evolution across environments as probed by the ages, stellar metallicities and [alpha/Fe] of central and satellite galaxies
• The AIMSS Project III: The Stellar Populations of Compact Stellar Systems
• Interaction between the Intergalactic Medium and Galactic Outflows from Dwarf Galaxies
• The Next Generation Virgo Cluster Survey. XII. Stellar Populations and Kinematics of Compact, Low-Mass Early-Type Galaxies from Gemini GMOS-IFU Spectroscopy
• A New Giant Stellar Structure in the Outer Halo of M31
• The Gas-Phase Metallicity of Central and Satellite Galaxies in the SDSS
• Barred Galaxies in the IllustrisTNG Simulation
• Environmental mechanisms shaping the nature of dwarf spheroidal galaxies; the view of computer simulations
• GASP XXX. The spatially resolved SFR-Mass relation in stripping galaxies in the local universe
• Jellyfish galaxies with the IllustrisTNG simulations -- When, where, and for how long does ram pressure stripping of cold gas occur?
• Tidal streams in newly discovered M32 analogues: evidence for the stripping scenario
• GASP XXVI. HI Gas in Jellyfish Galaxies: The case of JO201 and JO206
• Isolated compact elliptical galaxies: Stellar systems that ran away
• Ultra-Compact Dwarfs in the Core of the Coma Cluster
• Dual Effects of Ram Pressure on Star Formation in Multi-phase Disk Galaxies with Strong Stellar Feedback
• Environmental Effects on the Metal Enrichment of Low Mass Galaxies in Nearby Clusters
• Orbital evidences for dark-matter-free Milky Way dwarf spheroidal galaxies
• Tidal Distortions in NGC1052-DF2 and NGC1052-DF4: Independent Evidence for a Lack of Dark Matter
• An evolutionary continuum from nucleated dwarf galaxies to star clusters
• UCD Candidates in the Hydra Cluster
• The Formation of Compact Elliptical Galaxies in The Vicinity of A Massive Galaxy: The Role of Ram-pressure Confinement
• On the formation mechanisms of compact elliptical galaxies
• Stellar Systems in the direction of the Hickson Compact Group 44 - I. Low Surface Brightness Galaxies
• The Panchromatic Hubble Andromeda Treasury II. Tracing the Inner M31 Halo with Blue Horizontal Branch Stars
• Compact elliptical galaxies in different local environments: a mixture of galaxies with different origins?
• Ram pressure stripping of the multiphase ISM: a detailed view from TIGRESS simulations
• A search for massive UCDs in the Centaurus Galaxy Cluster
• The Origin of Stars in the Inner 500 Parsecs in TNG50 Galaxies
• Andromeda Optical and Infrared Disk Survey I. New Insights in Wide-Field Near-IR Surface Photometry
• The formation pathways of compact elliptical galaxies
• Discovery of a Bimodal Environmental Distribution of Compact Ellipticals in the Local Universe
• Testing the tidal stripping scenario of ultra-compact dwarf galaxy formation by using internal properties
• Chemodynamics of dwarf galaxies under ram-pressure
• What drives the corpulence of galaxies? I. The formation of central compact dwarf galaxies in TNG50
• Quantifying Bursty Star Formation in Dwarf Galaxies

Cited by in corpus (2)

• Accreted stars and stellar haloes of simulated galaxies in TNG50
• Tidal Grinding of Dwarf Galaxies in Cluster Environments