subgrid models of active galactic nuclei in clusters of galaxies Paul Matthew Sutter Paul M. Ricker Univ. of Illinois at Urbana-Champaign Frontiers in Computational Astrophysics Lyon, 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 Ghz 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 Ghz 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 M ʘ halo  fixed NFW potential (r s = 165 kpc)  r cool core = 40kpc  t cool ~ 6 Gyr  M bh = 10 7 M ʘ  ~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