THE BOLSHOI COSMOLOGICAL SIMULATIONS AND THEIR IMPLICATIONS JOEL - PowerPoint PPT Presentation

THE BOLSHOI COSMOLOGICAL SIMULATIONS AND THEIR IMPLICATIONS JOEL PRIMACK , UCSC Λ CDM Cosmological Parameters for Bolshoi and BigBolshoi Halo Mass Function is 10x Below Sheth-Tormen at z=10 Cluster Concentrations Agree with Λ CDM Predictions Improved Halo Finding and Merger Trees Predicted LMC/SMC Likelihood Agrees with Observations HAM Galaxy Correlations Agree with Observations HAM Galaxy Luminosity-Velocity Relations OK Galaxy Velocity Function OK for V circ > 80 km/s First Bolshoi and BigBolshoi data release in September 2011 Friday, August 12, 2011

The Millennium Run • void statistics , The Millennium Run • properties of including sizes and halos (radial was a landmark shapes and their profile, simulation, and it has evolution, and the concentration, orientation of halo been the basis for shapes) spins around voids ~400 papers. • evolution of the • quantitative number density descriptions of the of halos , essential evolving cosmic for normalization of web , including Press-Schechter- applications to weak type models gravitational lensing • evolution of the • preparation of distribution and mock catalogs , clustering of essential for halos in real and analyzing SDSS redshift space, for and other survey comparison with data, and for observations preparing for new • accretion large surveys for history of halos , dark energy etc. assembly bias • merger trees , (variation of large- essential for semi- scale clustering with analytic as- sembly history), modeling of the and correlation with halo properties evolving galaxy including angular population, including momenta and models for the shapes galaxy merger rate, • halo statistics the history of star including the mass formation and and velocity galaxy colors and functions, angular morphology, the momentum and evolving AGN shapes, subhalo luminosity function, numbers and stellar and AGN distribution, and feedback, recycling correlation with of gas and metals, environment Springel et al. 2005 etc. Friday, August 12, 2011

WMAP-only Determination of σ 8 and Ω M ● WMAP1 2003 T ext T ext T ext Text Text T ext T ext T ext T ext Text Text T ext T ext Text WMAP7 2010 ● ● WMAP5 2008 WMAP3 2006 ● Friday, August 12, 2011

WMAP+SN+Clusters Determination of σ 8 and Ω M Friday, August 12, 2011

WMAP+SN+Clusters Determination of σ 8 and Ω M Millennium is now about 4 σ away from observations WMAP7 ● WMAP5 ● Friday, August 12, 2011

σ 8 = 0.82 Cosmological parameters are consistent with the latest observations h = 0.70 Force and Mass Resolution are nearly an order of magnitude better than Millennium-I Force resolution is the same as Millennium-II, in a volume 16x larger Halo finding is complete to V circ > 50 km/s, using both BDM and ROCKSTAR halo finders Bolshoi and MultiDark halo catalogs will be released September 2011 at Astro Inst Potsdam and Stanford; Merger Trees will also soon be available Friday, August 12, 2011

1000 Mpc/h 8G particles BigBolshoi / MultiDark Same cosmology as Bolshoi: h=0.70, σ 8 =0.82, n=0.95, Ω m =0.27 7 kpc/h resolution, complete to V circ > 170 km/s Friday, August 12, 2011

Halos and galaxies: results from the Bolshoi simulation The Millennium Run (Springel+05) was a landmark simulation, and it has been the basis for ~400 papers. However, it and the new Millennium-II and XXL were run using WMAP1 (2003) parameters, and the Millennium-I resolution was inadequate to see many subhalos. The new Bolshoi simulation (Klypin, Trujillo & Primack 2011) used the WMAP5 parameters (consistent with WMAP7) and has nearly an order of magnitude better mass and force resolution than Millennium-I. We have now found halos in all 180 stored timesteps, and we have complete merger trees based on Bolshoi. Cosmological Parameters Klypin, Trujillo-Gomez, & Primack, arXiv:1002.3660 ApJ in press Subhalos follow the Velocity Function of dark matter distribution Distinct Halos at z = 6.5, 5, 3, 2, 0 Millennium Clusters Bolshoi old BDM halo finder Power Spectrum z = 6.5 5 3 2 0 Galaxies Friday, August 12, 2011

Sheth-Tormen Fails at High Redshifts Curve: Sheth- Tormen approx. FOF halos SO halos link = 0.20 z = 8.8 The Sheth-Tormen approximation with the same WMAP5 parameters used for the Bolshoi simulation very accurately agrees with abundance of halos at low redshifts, but increasingly overpredicts bound spherical overdensity halo abundance at higher redshifts. ST agrees well with FOF halo abundances, but FOF halos have unrealistically large masses at high z . Klypin, Trujillo-Gomez, & Primack, arXiv: 1002.3660 ApJ in press Friday, August 12, 2011

= ratio of FOF mass / SO mass FOF linked together a chain of halos that formed in long and dense filaments (also in panels b, d, f, h; e = major merger) Each panel shows 1/2 of the dark matter particles in cubes of 1 h -1 Mpc size. The center of each cube is the exact position of the center of mass of the corresponding FOF halo. The effective radius of each FOF halo in the plots is 150 − 200 h -1 kpc. Circles indicate virial radii of distinct halos and subhalos identified by the spherical overdensity algorithm BDM. Klypin, Trujillo-Gomez, & Primack, arXiv: 1002.3660 ApJ in press Friday, August 12, 2011

Bolshoi Simulation Analyzed by Various Halo Finders Halo Number Halo Correlations Density V max > 150 km/s 6 1 0 B D M 5 B D M N e w 1 0 s t a r R o c k 4 0 1 3 1 0 ! 2 1 0 1 1 0 0 1 0 All Halo V max Sub-Halo V max 1 0 1 0 . 1 . 0 1 0 -1 ] h r [ M p c Function Function Behroozi et al. in prep. Friday, August 12, 2011

Halo concentrations in the standard CDM cosmology Francisco Prada, Anatoly A. Klypin, Antonio J. Cuesta, Juan E. Betancort-Rijo , and Joel Primack Cluster Concentrations Note the upturn at high M and z 90%ile median Maccio 10%ile Comparison of observed cluster concentrations (data points with error Halo mass–concentration relation of distinct halos at bars) with the prediction of our model for median halo concentration of different redshifts in the Bolshoi (open symbols) and cluster-size halos (full curve). Dotted lines show 10% and 90% percentiles. Open circles show results for X-ray luminous galaxy clusters MultiDark (filled symbols) simulations is compared with observed with XMMNewton in the redshift range 0.1-0.3 (Ettori et al. an analytical approximation. 2010). The pentagon presents galaxy kinematic estimate for relaxed clusters by Wojtak & Lokas (2010). The dashed curve shows prediction by Macci`o, Dutton, & van den Bosch (2008), which significantly underestimates the concentrations of clusters. Friday, August 12, 2011

Halo concentrations in the standard CDM cosmology Francisco Prada, Anatoly A. Klypin, Antonio J. Cuesta, Juan E. Betancort-Rijo , and Joel Primack for Millennium-1,II and Bolshoi/MultiDark consistent consistent high z not consistent! consistent Friday, August 12, 2011

y r a n i m i l e r P 400 400 Fraction of z = 0 Fraction of z = 0 km/s 200 Halos Tracked to Halos Tracked to Given Redshift -- 200 Given Redshift -- New Method 100 Original Method 100 50 50 Friday, August 12, 2011

Behroozi et al. in prep. Friday, August 12, 2011

BOLSHOI Merger Tree Peter Behroozi, et al. Friday, August 12, 2011

The Milky Way has two large satellite galaxies, the small and large Magellanic Clouds The Bolshoi simulation + halo abundance matching predicts the likelihood of this Friday, August 12, 2011

0 1 2 0 1 2 Friday, August 12, 2011

Apply the same absolute magnitude and isolation cuts Statistics of MW bright satellites: to Bolshoi+SHAM galaxies as SDSS data vs. Bolshoi simulation to SDSS: Identify all objects with 1.000 absolute 0.1 M r = -20.73±0.2 M r,host = -20.73±0.2 and observed m r < 17.6 Probe out to z = 0.15, a M r,sat = M r,host + (2 − 4) volume of roughly 500 (Mpc/ h) 3 0.100 leaves us with 3,200 objects. Probability Comparison of Bolshoi with SDSS observations is in 0.010 close agreement, well within Every case agrees within observed statistical error observational errors! bars. SDSS Busha et al 2010 # of Subs Prob (obs) Prob (sim) Simulation 0.001 0 60% 61% 0 1 2 3 4 5 # of Satellites 1 22% 25% Risa Wechsler 2 13% 8.1% 3 4% 3.2% Similarly good agreement with SDSS for brighter satellites with 4 1% 1.4% spectroscopic redshifts compared with Millennium-II using abundance matching -- T olorud, Boylan-Kolchin, et al. 5 0% 0.58% Friday, August 12, 2011

Similarly good agreement with SDSS for brighter satellites with spectroscopic redshifts compared with Millennium-II using abundance matching. Real Pairs Good agreement between simulated and observed pairwise velocities: see James Bullock’s talk False Pairs Friday, August 12, 2011

Bolshoi z=0 Dark Matter Wechsler et al. Friday, August 12, 2011

Bolshoi z=0 SHAM Galaxies Wechsler et al. Friday, August 12, 2011

Bolshoi z=0 Dark Matter Bolshoi z=0 SHAM Galaxies Wechsler et al. Friday, August 12, 2011