Great Observatories donahue

Clusters of Galaxies: 

Clusters of Galaxies Megan Donahue Michigan State University Making the Most of the Great Observatories Workshop May 22-24, 2006 Pasadena,CA

Big Cluster Questions: 

Big Cluster Questions What is dark matter? What is accelerating the universe? How do galaxies form and evolve? What is the relationship between black holes and their galaxy and cluster hosts? Where are the baryons?

Dark Matters: 

Dark Matters 3 independent methods to estimate cluster masses: galaxy dynamics, hydrostatic X-ray gas, gravitational lensing. Nature of the dark matter may be revealed in M(r) (e.g. testing NFW M(r) predictions, constraints on self-interacting dark matter; MOND) Baryon/DM ratio if clusters are fair (or predictably biased) samples

Dark matter test: 

Dark matter test Bullet cluster 1E0657-56 Markevitch et al. 2004; Clowe et al. 2004 Difference between gravitational lensing and the main baryonic mass (the X-ray gas) contradicts MOND

Navarro-Frenk-White Profiles: 

Navarro-Frenk-White Profiles Clusters should be nearly self-similar throughout the cluster mass range. Concentration (rvirial/rscale) depends on formation epoch. Simulated clusters have c500~3 (2-6)

Abell 1689: 

Abell 1689 Broadhurst et al. 2004 30 galaxies, multiply lensed over 100 images NFW c=12.5-15.5 but cpred~ 3-4! (Be careful of how c is defined ...)

Slide7: 

Chandra:Scaled mass density profiles, 13 clusters Vikhlinin et al. 2006 Total Gas

Slide8: 

Concentration index from X-ray mass profiles (Vikhlinin et al 2006)

Lensing and X-rays: 

Lensing and X-rays X-rays reveal baryons responding to a dark matter potential well: method can only work for a (TBD) sub-sample of clusters. Lensing shows photons responding to matter along the line of sight, regardless of virialization state. Chandra and HST/ACS are ideal to provide the data for detailed comparisons.

Accelerating the universe: 

Accelerating the universe N(M,z) of clusters is extraordinarily sensitive to ΩM and σ8. Geometrical volume element z<0.5 Gravitational growth factor z>0.5 Evolution of the cluster mass function can distinguish “dark energy” models from modifications to gravity theory.

Cosmological simulations: the Millennium Run(Springel et al. 2005): 

Cosmological simulations: the Millennium Run (Springel et al. 2005)

dn/dM (from Millenium): 

dn/dM (from Millenium) Millennium Simulation Differential Halo Number Density

Cluster observables break parameter degeneracies multiple ways: 

Cluster observables break parameter degeneracies multiple ways Normalization and shape of the luminosity or temperature function. Evolution of the luminosity or temperature function. Cluster spatial correlation function

Cluster evolution is extremely sensitive to ΩM: 

Cluster evolution is extremely sensitive to ΩM Voit 2005

A large survey can distinguish w=-1 from w=-0.8: 

A large survey can distinguish w=-1 from w=-0.8 Voit 2005

Slide16: 

Reiprich 2006: HIFLUGCS 63 clusters. Concordance model (σ8=0.9, ΩM=0.3) predicted 200; WMAP 3 yr predicts 50 Recent WMAP result: σ8 and ΩM: Lx-M has small scatter & Mx may not need a fudge factor. σ8=0.74 ΩM=0.23

M-Tx Relation: 

M-Tx Relation 2006: Excellent agreement found between XMM (Arnaud et al. 2005) and Chandra (Vikhlinin et al. 2006)

Pratt et al. 2006 (points), grey band (ASCA) , Beppo/SAX (green), Chandra (red): 

Pratt et al. 2006 (points), grey band (ASCA) , Beppo/SAX (green), Chandra (red)

Cluster cosmology: 

Cluster cosmology Baryon fraction (Allen et al. 2002) N(M,z=0) (Reiprich, Bohringer, Henry) Evolution of N(T), N(Lx) (Eke, Cole, Frenk, Henry, Donahue) Cluster correlation function (Mohr) Cluster simulations (Evrard, Borgani)

Cluster cosmology: 

Cluster cosmology Baryon fraction (Allen et al. 2002) N(M,z=0) (Reiprich, Bohringer, Henry) Evolution of N(T), N(Lx) (Eke, Cole, Frenk, Henry, Donahue) Cluster correlation function (Mohr) Cluster simulations (Evrard, Borgani) Vikhlinin et al, 2005

Cluster cosmology: 

Cluster cosmology Baryon fraction (Allen et al. 2002) N(M,z=0) (Reiprich, Bohringer, Henry) Evolution of N(T), N(Lx) (Eke, Cole, Frenk, Henry, Donahue) Cluster correlation function (Mohr) Cluster simulations (Evrard, Borgani) Vikhlinin et al, 2005

Cluster Cosmology: 

Cluster Cosmology Multiple, independent observables constrain cosmological parameters: cross-calibration is an effective test of the validity of the approach. Limited by the accuracy of the mass-observable calibration. Limited by the small catalogs of clusters at z~0.5

Slide23: 

CCCP Clusters Hoekstra 160SD Clusters Donahue Weak Lensing (H0=70)

Spitzer spies high-z clusters in 90 second IRAC exposures: 

Spitzer spies high-z clusters in 90 second IRAC exposures Stanford et al.2005, z~1.4 1-2 micron peak, highly visible in near - mid IR

Cluster Cosmology: 

Cluster Cosmology The time for calibration is now, while Chandra and XMM still work. Key future cluster surveys: South Pole Telescope (4000 sq deg). HST: gravitational lensing Spitzer: high redshift cluster discovery.

Black holes and clusters: 

Black holes and clusters Bubbles and shocks in the IGM are allowing the total kinetic output and duty cycle of an AGN to be measured for the first time. (e.g. McNamara, Nulsen, Fabian) AGN feedback appears to play a crucial role in determining the high L cutoff in the galaxy luminosity function. (e.g. Springer, Kauffmann, Somerville) AGN feedback appears to play a crucial role in moderating the thermal properties of the gas in the “cooling flows.” (e.g. Donahue, Voit, Fabian) The biggest black holes in the universe are expected to reside in the biggest galaxies (e.g. Springer et al). Do they?

Radio sources & the ICM: 

Radio sources & the ICM Hydra A, McNamara et al. 2001

Slide28: 

Donahue et al. 2005, 2006

Slide29: 

Perseus (Fabian et al 2006) 900 ksec 0.3-1.2 keV red 1.2-2 keV green 2-7 keV blue

Slide30: 

M87 500 ksec Forman et al. 2006 0.5-1.0 keV 3.5-7.5 keV

Black hole masses: 

Black hole masses Gebhardt et al 2000

Brightest galaxies in clusters: 

Brightest galaxies in clusters Abell 1650 MI ~-24 Abell 2244

Brightest galaxies in clusters: 

Brightest galaxies in clusters Abell 1650 MI ~-24 Abell 2244 1010 solar masses?

Galaxy evolution and star formation: 

Galaxy evolution and star formation Ellipticals seem to have a very simple star formation history, and dominate the cores of clusters out to z>1. (Stanford, Postman, Lubin, Dressler) Ellipticals in clusters differ morphologically from those in the field. (Conselice, Donahue) Field ellipticals have bluer cores (Menanteau / Treu /Pasquali) But the bulk of star formation in ellipticals seems to happen before there is much of a cluster (Blakeslee et al.; Mei et al.) The highest redshift clusters observed seem well supplied with Fe (Rosati, Mullis).

Great Observatories: 

Great Observatories Quantify the star formation rate in cDs, cluster galaxies, groups, and infall regions (Spitzer, followup with NIR ground-based observations) Morphological classification in dense environments, z>0 (HST) Metal abundances in ICM (Chandra) Metal absorption in IGM/ICM (HST/SM4)

Three projects: 

Three projects Spitzer high-z cluster search (overlap Chandra & SZ/SPT fields) Chandra & HST cluster mass calibration (overlap SZ/SPT fields): Lx, Tx, optical richness, shear, gas mass, SZ decrement AGN feedback at Chandra resolution. Capture in situ AGN interaction between ICM & AGN: deep Chandra observations, Spitzer star formation rates (black hole masses using STIS?)

Where are the baryons?: 

Where are the baryons? Most of them are in the (dark) IGM. 0.5-1.0 million second observations of AGN in “high states” have not produced statistically significant detections of X-ray absorption with z>0. Needs Con-X. More detections have been made by HST and FUSE with OVI absorption features: HST/COS & HST/STIS (if SM4 happens)