Post on 05-Jan-2016
description
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu
Large-Scale Large-Scale Structure with Structure with
Interacting Interacting Dark Matter Dark Matter
and Dark Energyand Dark Energy
Paul Matthew SutterUniversity of Illinois at Urbana-Champaign
With:Paul Ricker, Ben Wandelt, and Greg Huey
(Sutter and Ricker, 2006)
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu2
Completely Unknown
75%
Somewhat unknown
4%
Largely Unknown
21%
The Conundrum of ConcordanceThe Conundrum of Concordance
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu3
PlaybillPlaybill
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 growthOpen up parameter space and explore large-scale consequences
“Are the various models distinguishable?”“If so, where should we look?”
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu4
Introducing the Players…Introducing the Players…
•A scalar field responsible for the dark energy:
•A dark matter particle family with field-dependent mass:
•Doing usual perturbation theory:
)(2
1 ,,
4 VgxdSDE
i
DM
dsy
yigxdSi
*
*4 )(
)(),(
),()(
1
1
ttx
txt
b
b
(Farrar & Peebles, 2004)
0let
1
*
DMv
Taking classical limit
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu5
The Major Story ArcsThe Major Story Arcs
Get the following Equations of Motion:
•DM particle:
•DE background field:
•DE perturbation field:
)(
1 1
taa
a
bb
b
vv
0)(
1
8
3)(3 3
0
20 a
tGH
d
dV
a
am
bbb
byna 21
2 /
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu6
Interactions & DialoguesInteractions & Dialogues
Modifications to standard cosmology:
)(
1 1
taa
a
bb
b
vv
A new Friedmann equation:
)(
2
1
3
82
3
0
20
2
Vdt
dGaH
a
am
An additional term in DM EoM
A time-dependent DM particle mass
A fifth force!
25 )(
1
tF th
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu8
Backstage…Backstage…
Using a customized version of FLASH, an Adaptive Mesh Refinement (AMR) tool for astrophysics and cosmology.
FLASH uses a multigrid particle-mesh algorithm.
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 halos71.0,7.0,0.0,3.0 hbm
(Fryxell et al., 2000)
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu9
Potential for a HitPotential for a Hit
Example: a power-law potential: /)( KV
PASCOS '06 at OSUApril 20, 2023
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The Finale: A Comedy?...The Finale: A Comedy?...
PASCOS '06 at OSUApril 20, 2023
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……Or Tragedy?Or Tragedy?
Attempt to fit our radial density profiles to the
NFW profile:
21
)(
ss
s
crit rrrr
r
(Navarro, Frenk, White, 1997)
Happens in all models…
YIKES!!Need more resolution…
PASCOS '06 at OSUApril 20, 2023
psutter2@uiuc.edu12
The SequelsThe Sequels
These results are preliminary, but suggestive!Good: get mass functions consistent with standard
cosmologiesBad: 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!