A Sagittarius-like simulated dwarf spheroidal galaxy from TNG50

Abstract

The Sagittarius dwarf spheroidal (Sgr dSph) galaxy provides one of the most convincing examples of tidal interaction between satellite galaxies and the Milky Way (MW). The main body of the dwarf was recently demonstrated to have an elongated, prolate, bar-like shape and to possess some internal rotation. Whether these features are temporary results of the strong tidal interaction at the recent pericenter passage or are due to a disky progenitor is a matter of debate. I present an analog of Sgr selected among bar-like galaxies from the TNG50 simulation of the IllustrisTNG project. The simulated dwarf is initially a disky galaxy with mass exceeding $10^{11}$ M${}_{\odot }$ and evolves around a MW-like host on a tight orbit with seven pericenter passages and a period of about 1 Gyr. At the second pericenter passage, the disk transforms into a bar and the bar-like shape of the stellar component is preserved until the end of the evolution. The morphological transformation is accompanied by strong mass loss, leaving a dwarf with a final mass of below $10^9$ M${}_{\odot }$. The gas is lost completely and the star formation ceases at the third pericenter passage. At the last pericenters, the dwarf possesses a bar-like shape, a little remnant rotation, and the metallicity gradient, which are consistent with observations. The more concentrated metal-rich stellar population rotates faster and has a lower velocity dispersion than the more extended metal-poor one. The metallicity distribution evolves so that the most metal-poor stars are stripped first, which explains the metallicity gradient detected in the Sgr stream. This study demonstrates that a dSph galaxy with properties akin to the Sgr dwarf can form from a disky progenitor with a mass of above $10^{11}$ M${}_{\odot }$ by tidal evolution around the MW in the cosmological context.

arXiv comment10 pages, 11 figures, accepted for publication in A&A

References in corpus (48)

• 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
• First results from the IllustrisTNG simulations: the galaxy color bimodality
• First results from the IllustrisTNG simulations: A tale of two elements -- chemical evolution of magnesium and europium
• A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: I. Morphology of the Sagittarius Core and Tidal Arms
• 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
• The Ghost of Sagittarius and Lumps in the Halo of the Milky Way
• Morphology, photometry and kinematics of N-body bars. I Three models with different halo central concentrations
• Great Circle tidal streams: evidence for a nearly spherical massive dark halo around the Milky Way
• The optical morphologies of galaxies in the IllustrisTNG simulation: a comparison to Pan-STARRS observations
• Bar formation and evolution in disc galaxies with gas and a triaxial halo: Morphology, bar strength and halo properties
• The Kinematics, Orbit, and Survival of the Sagittarius Dwarf Spheroidal Galaxy
• The Size Evolution of Star-forming and Quenched Galaxies in the IllustrisTNG simulation
• The Disruption of the Sagittarius Dwarf Galaxy.
• The ACS Survey of Galactic Globular Clusters: M54 and Young Populations in the Sagittarius Dwarf Spheroidal Galaxy
• Galactic Angular Momentum in the Illustris Simulation: Feedback and the Hubble Sequence
• Precession of the Sagittarius stream
• Tidal tails in CDM cosmologies
• Sagittarius Tidal Debris 90 kpc from the Galactic Center
• The Sagittarius Streams in the Southern Galactic Hemisphere
• Tracing out the Northern Tidal Stream of the Sagittarius Dwarf Spheoridal Galaxy
• Was the Progenitor of the Sagittarius Stream a Disc Galaxy?
• Simple dynamical models of the Sagittarius dwarf galaxy
• The Overdensity in Virgo, Sagittarius Debris, and the Asymmetric Spheroid
• The last breath of the Sagittarius dSph
• A Tail of Two Populations: Chemo-dynamics of the Sagittarius Stream and Implications for its Original Mass
• Adventures of a tidally induced bar
• The Orbit and Mass of the Sagittarius Dwarf Galaxy
• Metallicity and $\alpha$-element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE
• The fate of disk galaxies in IllustrisTNG clusters
• The inner structure and kinematics of the Sagittarius dwarf galaxy as a product of tidal stirring
• The orientation and kinematics of inner tidal tails around dwarf galaxies orbiting the Milky Way
• Formation of tidally induced bars in galactic flybys: prograde versus retrograde encounters
• The Geometry of Sagittarius Stream from Pan-STARRS1 3$\pi$ RR Lyrae
• An all-sky proper motion map of the Sagittarius stream using Gaia DR2
• No evidence for internal rotation in the remnant core of the Sagittarius dwarf
• A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: VII. Kinematics of the Main Body of the Sagittarius dSph
• The stellar metallicity gradients of Local Group dwarf galaxies
• Discovery of a Dynamical Cold Point in the Heart of the Sagittarius dSph Galaxy with Observations from the APOGEE Project
• The resonant nature of tidal stirring of disky dwarf galaxies orbiting the Milky Way
• Revealing the Structure and Internal Rotation of the Sagittarius Dwarf Spheroidal Galaxy with Gaia and Machine Learning
• Tidally induced bars in dwarf galaxies on different orbits around a Milky Way-like host
• Bar-like galaxies in IllustrisTNG
• Phase-space Properties and Chemistry of the Sagittarius Stellar Stream Down to the Extremely Metal-poor ($[Fe/H]\lesssim -3$) Regime
• Tidally induced bars in gas-rich dwarf galaxies orbiting the Milky Way
• The metallicity distribution in the core of the Sagittarus dwarf spheroidal: minimising the metallicity biases
• The Pristine Inner Galaxy Survey (PIGS) IV: A photometric metallicity analysis of the Sagittarius dwarf spheroidal galaxy

Cited by in corpus (4)

• Looking into the faintEst WIth MUSE (LEWIS): Exploring the nature of ultra-diffuse galaxies in the Hydra-I cluster II. Stellar kinematics and dynamical masses
• The Pristine Inner Galaxy Survey (PIGS) X. Probing the early chemical evolution of the Sagittarius dwarf galaxy with carbon abundances
• The oldest tidally induced bar-like galaxy in the IllustrisTNG cluster
• Kinematics of the Sagittarius Dwarf Spheroidal core: A 5D Analysis for a 6D Methodology with Gaia DR3