Statistical properties of substructures around Milky Way-sized haloes and their implications for the formation of stellar streams

Abstract

Stellar streams originating in disrupted dwarf galaxies and star clusters are observed around the Milky Way and nearby galaxies. Such substructures are the important tracers that record how the host haloes have accreted progenitor galaxies. Based on the cosmological context, we investigate the relationship between structural properties of substructures such as length and thinness at $z=0$, and orbits of their progenitors. We model stellar components of a large sample of substructures around Milky Way-sized haloes by combining semi-analytic models with a high-resolution cosmological $N$-body simulation. Using the Particle Tagging method, we embed stellar components in progenitor haloes and trace phase-space distributions of the substructures down to $z=0$. We find that the length and thinness of substructures vary smoothly as the redshift when the host haloes accrete their progenitors. For substructures observed like streams at $z=0$, a large part of the progenitors is accreted by their host haloes at redshift $0.5\lesssim z\lesssim 2.5$. Substructures with progenitors out of this accretion redshift range are entirely or less disrupted by $z=0$ and cannot be observed as streams. We also find that the distributions of length and thinness of substructures vary smoothly as pericenter and apocenter of the progenitors. Substructures observed like streams tend to have the specific range of $10\mathrm{kpc}\lesssim r_{\mathrm{peri}}\lesssim 100\mathrm{kpc}$ and $50\mathrm{kpc}\lesssim r_{\mathrm{apo}}\lesssim 300\mathrm{kpc}$.

Accepted for publication in MNRAS, 13 pages, 10 figures, 1 table

References in corpus (20)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from the WMAP data
• Massloss of galaxies due to a UV-background
• Tracing Galaxy Formation with Stellar Halos II: Relating Substructure in Phase- and Abundance-Space to Accretion Histories
• An Orphan in the "Field of Streams"
• The Galaxy and its stellar halo: insights on their formation from a hybrid cosmological approach
• The ghost of a dwarf galaxy: fossils of the hierarchical formation of the nearby spiral galaxy NGC 5907
• Substructure in Tidal Streams; Tributaries in the Anticenter Ring
• Investigating the Andromeda Stream: III. A Young Shell System in M31
• Shaken and Stirred: The Milky Way's Dark Substructures
• Satellites of Simulated Galaxies: survival, merging, and their relation to the dark and stellar halos
• Dynamics of the Magellanic Clouds in a LCDM Universe
• On the formation of extended galactic disks by tidally disrupted dwarf galaxies
• A New Milky Way Satellite Discovered In The Subaru/Hyper Suprime-Cam Survey
• Was the Andromeda Stream Produced by a Disk Galaxy?
• Kinematics and simulations of the stellar stream in the halo of the Umbrella Galaxy
• The Tidal Streams of Disrupting Subhaloes in Cosmological Dark Matter Haloes
• On the dust content of galaxy clusters
• Development of multiple tidal tails around globular clusters and dwarf satellite galaxies
• The course of the Orphan Stream in the Northern Galactic Hemisphere traced with Gaia DR2
• Quantifying tidal stream disruption in a simulated Milky Way

Cited by in corpus (4)

• Reconstructing the Disrupted Dwarf Galaxy $Gaia$-Sausage/Enceladus Using its Stars and Globular Clusters
• Phase-space Properties and Chemistry of the Sagittarius Stellar Stream Down to the Extremely Metal-poor ($[Fe/H]\lesssim -3$) Regime
• Possibilities and Limitations of Kinematically Identifying Stars from Accreted Ultra-Faint Dwarf Galaxies
• Extending the Chemical Reach of the H3 Survey: Detailed Abundances of the Dwarf-galaxy Stellar Stream Wukong/LMS-1