Creating mock catalogues of stellar haloes from cosmological simulations

Abstract

We present a new technique for creating mock catalogues of the individual stars that make up the accreted component of stellar haloes in cosmological simulations and show how the catalogues can be used to test and interpret observational data. The catalogues are constructed from a combination of methods. A semi-analytic galaxy formation model is used to calculate the star formation history in haloes in an N-body simulation and dark matter particles are tagged with this stellar mass. The tags are converted into individual stars using a stellar population synthesis model to obtain the number density and evolutionary stage of the stars, together with a phase-space sampling method that distributes the stars while ensuring that the phase-space structure of the original N-body simulation is maintained. A set of catalogues based on the $\Lambda$CDM Aquarius simulations of Milky Way mass haloes have been created and made publicly available on a website. Two example applications are discussed that demonstrate the power and flexibility of the mock catalogues. We show how the rich stellar substructure that survives in the stellar halo precludes a simple measurement of its density profile and demonstrate explicitly how pencil-beam surveys can return almost any value for the slope of the profile. We also show that localized variations in the abundance of particular types of stars, a signature of differences in the composition of stellar populations, allow streams to be easily identified.

19 pages, 13 figures, accepted by MNRAS

References in corpus (15)

• A primer on hierarchical galaxy formation: the semi-analytical approach
• The redshift dependence of the structure of massive LCDM halos
• The Haunted Halos of Andromeda and Triangulum: A panorama of galaxy formation in action
• Tracing Galaxy Formation with Stellar Halos II: Relating Substructure in Phase- and Abundance-Space to Accretion Histories
• Velocity Dispersion Profiles of Seven Dwarf Spheroidal Galaxies
• A blueprint for detecting supersymmetric dark matter in the Galactic halo
• The Galaxy and its stellar halo: insights on their formation from a hybrid cosmological approach
• Halo Mass and Assembly History Exposed in the Faint Outskirts: the Stellar and Dark Matter Haloes of Illustris Galaxies
• The abundance of (not just) dark matter haloes
• A 2MASS All-Sky View of the Sagittarius Dwarf Galaxy: Variation of the Metallicity Distribution Function Along the Sagittarius Stream
• Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey
• Revealing Substructure in the Galactic Halo - The SEKBO RR Lyrae Survey
• Metallicity Bias in the Kinematics of the Milky Way Stellar Halo
• Does SEGUE/SDSS indicate a dual Galactic halo?
• Surface photometry of BCGs and intracluster stars in Lambda-CDM

Cited by in corpus (14)

• A box full of chocolates: The rich structure of the nearby stellar halo revealed by Gaia and RAVE
• The information content of stellar halos: Stellar population gradients and accretion histories in early-type Illustris galaxies
• The Stellar Halo of the Galaxy is Tilted & Doubly Broken
• The stellar kinematics of co-rotating spiral arms in Gaia mock observations
• On the Galactic rotation curve inferred from the Jeans equations Assessing its robustness using Gaia DR3 and cosmological simulations
• The shapes and alignments of the satellites of the Milky Way and Andromeda
• An observational testbed for cosmological zoom-in simulations: constraining stellar migration in the solar cylinder using asteroseismology
• GalaxyFlow: Upsampling Hydrodynamical Simulations for Realistic Mock Stellar Catalogs
• AuriDESI: Mock Catalogues for the DESI Milky Way Survey
• Building Blocks of the Milky Way's Accreted Spheroid
• Glow in the Dark Matter: Observing galactic halos with scattered light
• Machine Learning the Dark Matter Halo Mass of Milky Way-Like Systems
• Stellar halo striations from assumptions of axisymmetry
• Probing the spatial and velocity anisotropies in stellar halos from the Aquarius simulations