subgrid modelsof

active galactic nuclei

inclusters of

galaxies

Paul Matthew Sutter Paul M. Ricker

Univ. of Illinois at Urbana-Champaign

Frontiers in Computational AstrophysicsLyon, France 10/14/2010

clusters and cosmology

why bother?

next-gen surveys will get ~10,000 clusters

significance will be reduced by systematics

must understand cluster astrophysics to constrain these systematics

magnetic fields play large role in cluster physics, but are poorly understood...

DES 500 Megapixel

camera at Blanco 4-meter telescope

5000 square-degree survey

radio halos

Abell 2163

1.4Ghz Radio Contours (GMRT, India)

and ROSAT X-ray emission

(Feretti et al. 2001)

radio mini-halos

(Burns et al. 1992, Sibring 1993)

(Fabian et al. 2000)

Perseus Cluster

radio relics

Abell 2163

1.4Ghz Radio Contours (GMRT, India)

and ROSAT X-ray emission

(Bagchi et al. 2006)

seeding magnetic fields

seeds via Biermann battery

amplification via stellar or AGN accretion disks

ejection via winds or AGN

agn

jet injection

Cattaneo & Teyssier (2007)

jet energy linked to accretion rate

assume entrainment factor

cylindrical feedback region

kinetic, thermal, and mass injection

jets point along axis

magnetic field injection

Li et al. (2006)

appropriate for jets and bubbles

poloidal and toroidal components

assumes underlying dynamo-like system

free to choose scale radius, magnetic field strength

FLASH

oct-tree adaptive mesh refinement

Gravity: N-body particle-mesh multigrid+pFFT

Hydro: PPM MHD: Constrained-

Transport SM sutherland & dopita

radiative cooling fast on-the-fly halo finding scales well to >200,000

processors

(Fryxell et al. 2000)

test setup

mock 1014 Mʘ halo fixed NFW potential

(rs = 165 kpc)

rcool core = 40kpc

tcool ~ 6 Gyr

Mbh = 107 Mʘ

~0.5 kpc resolution

injected magnetic field

accretion rate

magnetized cluster

preliminary conclusions

magnetizing jets severely lowers accretion rates

magnetic energy much less than Liu et al. (2007), Xu et al. (2008)

can weakly magnetize entire cluster with jets, strong fields in cores (mini-halos?)

outro

clusters offer unique window on universe

must understand astrophysics to understand cosmology

magnetic fields impact cluster physics

simulations can help us understand magnetic fields