Faint dwarfs as a test of DM models: WDM vs. CDM

Abstract

We use high resolution Hydro$+$N-Body cosmological simulations to compare the assembly and evolution of a small field dwarf (stellar mass ~ 10${}^{6-7}$ M$\odot$, total mass 10${}^{10}$ M$\odot$ in $\Lambda$ dominated CDM and 2keV WDM cosmologies. We find that star formation (SF) in the WDM model is reduced and delayed by 1-2 Gyr relative to the CDM model, independently of the details of SF and feedback. Independent of the DM model, but proportionally to the SF efficiency, gas outflows lower the central mass density through `dynamical heating', such that all realizations have circular velocities $<$ 20kms at 500 pc, in agreement with local kinematic constraints. As a result of dynamical heating, older stars are less centrally concentrated than younger stars, similar to stellar population gradients observed in nearby dwarf galaxies. Introducing an important diagnostic of SF and feedback models, we translate our simulations into artificial color-magnitude diagrams and star formation histories in order to directly compare to available observations. The simulated galaxies formed most of their stars in many $\sim$10 Myr long bursts. The CDM galaxy has a global SFH, HI abundance and Fe/H and alpha-elements distribution well matched to current observations of dwarf galaxies. These results highlight the importance of directly including `baryon physics' in simulations when 1) comparing predictions of galaxy formation models with the kinematics and number density of local dwarf galaxies and 2) differentiating between CDM and non-standard models with different DM or power spectra.

13 pages including Appendix on Color Magnitude Diagrams. Accepted by MNRAS. Added one plot and details on ChaNGa implementation. Reduced number of citations after editorial request

References in corpus (20)

• Star Formation in AEGIS Field Galaxies since z=1.1 : The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-Forming Galaxies
• Star Formation and Feedback in Smoothed Particle Hydrodynamic Simulations--I. Isolated Galaxies
• The ACS Nearby Galaxy Survey Treasury
• Dark matter and cosmic structure
• Stellar Feedback in Dwarf Galaxy Formation
• The ACS Nearby Galaxy Survey Treasury IX. Constraining asymptotic giant branch evolution with old metal-poor galaxies
• The Baryon Content of Extremely Low Mass Dwarf Galaxies
• Too Big to Fail in the Local Group
• Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter
• A Superbubble Feedback Model for Galaxy Simulations
• Leo A: A Late-Blooming Survivor of the Epoch of Reionization in the Local Group
• The Star Formation Histories of Local Group Dwarf Galaxies II. Searching For Signatures of Reionization
• The Impact of Feedback on Disk Galaxy Scaling Relations
• Dark Matter Heating and Early Core Formation in Dwarf Galaxies
• Hubble Space Telescope Grism Spectroscopy of Extreme Starbursts Across Cosmic Time: The Role of Dwarf Galaxies in the Star Formation History of the Universe
• Kinematic Evolution of Simulated Star-Forming Galaxies
• Building the Stellar Halo Through Feedback in Dwarf Galaxies
• Running with BICEP2: Implications for Small-Scale Problems in CDM
• The main sequence of star-forming galaxies at z~0.6: reinstating major mergers
• Reversal of Fortune: Increased Star Formation Efficiencies in the Early Histories of Dwarf Galaxies?

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• When the Jeans don't fit: How stellar feedback drives stellar kinematics and complicates dynamical modeling in low-mass galaxies
• Fundamental physics with the Hubble Frontier Fields: constraining Dark Matter models with the abundance of extremely faint and distant galaxies
• The edge of galaxy formation I: formation and evolution of MW-satellites analogues before accretion
• A unified solution to the small scale problems of the $\Lambda$CDM model II: introducing parent-satellite interaction
• Simulations of galaxies formed in warm dark matter halos of masses at the filtering scale
• The edge of galaxy formation III: The effects of warm dark matter on Milky Way satellites and field dwarfs
• Beacons In the Dark: Using Novae and Supernovae to Detect Dwarf Galaxies in the Local Universe