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Large-Scale Structure with Interacting Dark Matter and Dark Energy. Paul Matthew Sutter University of Illinois at Urbana-Champaign. (Sutter and Ricker, 2006). With: Paul Ricker, Ben Wandelt, and Greg Huey. The Conundrum of Concordance. Playbill. Essential Problem:
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Large-Scale Structure with Interacting Dark Matter and Dark Energy Paul Matthew Sutter University of Illinois at Urbana-Champaign (Sutter and Ricker, 2006) With: Paul Ricker, Ben Wandelt, and Greg Huey PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
The Conundrum of Concordance PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
Playbill • Essential Problem: • Explain “coincidence” of dark matter (DM) and dark energy (DE) • Essential Solution: • Coincidence? Anthropic selection? Or allow DM and DE to interact! • Previous Work: • Farrar & Peebles (2004) develop theoretical model (summarized soon) • F&P examine H(t), linear effects, etc.; able to reject some models • Nusser et al. (2005) do limited simulations involving screened potential • What we’re after: • Fully realize F&P’s dynamics in N-body simulations of cluster growth • Open up parameter space and explore large-scale consequences • “Are the various models distinguishable?” • “If so, where should we look?” PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
Introducing the Players… • A scalar field responsible for the dark energy: • A dark matter particle family with field-dependent mass: • Doing usual perturbation theory: (Farrar & Peebles, 2004) Taking classical limit PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
The Major Story Arcs • Get the following Equations of Motion: • DE background field: • DE perturbation field: • DM particle: PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
Interactions & Dialogues • An additional term in DM EoM • A fifth force! • A time-dependent DM particle mass • Modifications to standard cosmology: • A new Friedmann equation: PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
Backstage… • Using a customized version of FLASH, an Adaptive Mesh Refinement (AMR) tool for astrophysics and cosmology. • FLASH uses a multigrid particle-mesh algorithm. (Fryxell et al., 2000) • Simulation parameters: • 64 Mpc/h cubic box • 256^3 particles • 256^3 mesh • No AMR • z=50 to z=0 • Halos are found with • FoF method: • 1/5 grid maximum linking distance • 3000 particle minimum in halos PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
Potential for a Hit • Example: a power-law potential: PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
The Finale: A Comedy?... PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
…Or Tragedy? • Attempt to fit our radial • density profiles to the • NFW profile: (Navarro, Frenk, White, 1997) • Happens in all models… • YIKES!! • Need more resolution… PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu
The Sequels • These results are preliminary, but suggestive! • Good: get mass functions consistent with standard cosmologies • Bad: get mass functions consistent with standard cosmologies • Ugly: resolution too poor to resolve cores • What we’re working on: • Larger grids with AMR (currently queued at NCSA) • More detailed statistical analysis • Time-evolution of halo structure • Other linear potentials • Multiple DM particle families • Non-perturbative methods • Paper coming soon! PASCOS '06 at OSU 21 October 2014 psutter2@uiuc.edu