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SZ Surveys Are Coming: What should we do?

This article discusses the importance of SZ effect and the need for large, homogeneous catalogs of galaxy clusters at high redshifts. It explores various survey methods such as optical/IR imaging, X-ray imaging, and weak lensing, and highlights ongoing SZ surveying projects. The article also emphasizes the efficiency and unique properties of SZ cluster surveys for studying cluster evolution and cosmological parameters.

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SZ Surveys Are Coming: What should we do?

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  1. SZ Surveys Are Coming:What should we do? James G. Bartlett APC - Université Paris 7 Collabs: J.-B. Melin (CEA), J. Delabrouille (APC), S. Mei (JHU)

  2. Aims • Coming breakthrough at z~1: hundred-fold increase in galaxy cluster numbers • Taste for the science with clusters • Importance of SZ effect • Some catalog construction issues • More studies needed Rencontres de Moriond J. Bartlett

  3. SZ Surveying Projects • Interferometers: ~10-100 sq. deg. • Arcminute MicroKelvin Imager(AMI) (in operation) first image: astro-ph/0509215 • 10 antennas (3.7m), 15 GHz, + Ryle Telescope • Array for Microwave Background Anisotropy (AMIBA) • 19 antennas (0.3m), 90 GHz, Hawaii • SZ Array (in operation) • 8 antennas (3.5m), 30 GHz + 90GHz follow-up, + OVRO/BIMA • Bolometer arrays: ~100-4000 sq. deg. • ACBAR:4 band-4element array at South Pole (in operation) • BOLOCAM: 150 element array (in operation) • APEX: ALMA prototype, 300 element array (2006) • ACT: Atacama plateau, 1000 element array (2006) • SPT: 10m dish, 1000 element array (2007/2008) • Planck: launch 2007/2008, all-sky • ~10,000 clusters Rencontres de Moriond J. Bartlett

  4. Galaxy Clusters Galaxies: Early types 10 - 1000 poor groups - rich clusters POSS Gas: Heated by infall Chandra Dark Matter: Rencontres de Moriond J. Bartlett

  5. Cosmology with Clusters • Environment for galaxy formation studies Interplay between stars, galaxies, gas & dark matter • Stellar mass build-up; Hubble sequence transformations • Feedback/cooling effects (over a large range of masses) • Efficient tracers of large-scale structure good sampling, simple bias • Baryon acoustic oscillations • Properties and evolution are sensitive to cosmology & density perturbations • Cosmological parameters; e.g., dark energy • Gaussianity of the perturbations • Hubble diagram (SZ + Xrays) Rencontres de Moriond J. Bartlett

  6. Efficient Tracers of LSS • Good sampling: • Simple bias: (Mo & White 1996) • cluster = halo Clusters M>1014 SDSS LRGs Clusters M>2x1014 Eisenstein et al. 2005, ApJ 633, 560 Sheth & Tormen 1999 Rencontres de Moriond J. Bartlett

  7. Abundance & Evolution Cluster evolution constrains cosmological parameters M M M Rencontres de Moriond J. Bartlett

  8. Cluster Surveys Need large, homogeneous (in mass) catalogs to z>1 Current list of spectroscopically confirmed z>1 clusters from optical/NIR imaging & X-ray surveying X-ray Today: ~ 10 at z>1 Rencontres de Moriond J. Bartlett

  9. Cluster SurveysMethods • Optical/IR imaging: Early type galaxy colors (e.g., darkCAM, DES, ISCS, LSST, Pan-starrs, RCS1&2 ,…) • Good contrast • Relation to mass • X-ray imaging:Lx from hot gas (e.g., review by Rosati et al. 2002, XCS) • Good contrast • T tightly correlated to mass • All-sky surveys - shallow • Deeper serendipitous - limited area, inhomogeneous • Weak lensing:shear/aperture mass (e.g., DUNE, JDEM) • Direct relation to mass • Projection effects Rencontres de Moriond J. Bartlett

  10. Sunyaev-Zel’dovich Effect(s) T~5keV (CL0016 Carlstrom et al.) Rencontres de Moriond J. Bartlett

  11. Thermal SZ Effect For y << 1 and Tg/Te << 1 (Ok for clusters) x+ = 6.51 x- = 2.26 2.28 104mJy/arcmin2 Compton y parameter xo = 3.83 ~10-4 d For Tcmb =2.726K - o + - = 128 GHz - = 2.34 mm o = 1.38 mm o = 218 GHz + = 0.80 mm + = 370 GHz Rencontres de Moriond J. Bartlett

  12. SZ Cluster Surveys (Korolov et al, 1986, JGB & Silk 1994, Barbosa et al. 1996, Eke et al. 1996…) A SZ `flux’-limited survey Important properties (Bartlett 2001) • Efficient at high z i = const, SszDang-2 • Spectral signature unique, no k-correction • Ssz  gas thermal energy robust, independent of spatial/ thermal structure Rencontres de Moriond J. Bartlett

  13. SZ Cluster Surveys Y Intrinsic scatter Insensitive to mergers, thermal structure, etc M Motl et al. 2005, ApJ 623, L63 Planck 3 Close to a mass selected catalog, uniform in redshift Detection mass Ground 5 Important for evolutionary studies - same kind of object observed at different epochs Rencontres de Moriond J. Bartlett

  14. SZ Surveying Projects • Interferometers: ~10-100 sq. deg. • Arcminute MicroKelvin Imager(AMI) (in operation) first image: astro-ph/0509215 • 10 antennas (3.7m), 15 GHz, + Ryle Telescope • Array for Microwave Background Anisotropy (AMIBA) • 19 antennas (0.3m), 90 GHz, Hawaii • SZ Array (in operation) • 8 antennas (3.5m), 30 GHz + 90GHz follow-up, + OVRO/BIMA • Bolometer arrays: ~100-4000 sq. deg. • ACBAR:4 band-4element array at South Pole (in operation) • BOLOCAM: 150 element array (in operation) • APEX: ALMA prototype, 300 element array (2006) • ACT: Atacama plateau, 1000 element array (2006) • SPT: 10m dish, 1000 element array (2007/2008) • Planck: launch 2007/2008, all-sky • ~10,000 clusters Rencontres de Moriond J. Bartlett

  15. (Great) Expectations • Cluster detection & catalog construction method Spectro-spatial matched filter (Melin, JGB, Delabrouille 2005, 2006) • Expected cluster numbers and redshift distributions • Examine cluster catalog construction & observational uncertainties • Selection criteria • Photometry Rencontres de Moriond J. Bartlett

  16. Catalog Extraction Melin, JGB, Delabrouille Simulated observation Input clusters • 15 GHz simulation with • primary CMB • point sources < 100 Jy • fwhm=2 arcmin • noise = 5 K/lobe • Selection criteria • Photometry Rencontres de Moriond APC U. Paris 7

  17. Case Studies 3 deg 3 deg Many simulations of each experimental setup Rencontres de Moriond J. Bartlett

  18. Completeness Primary CMB confusion Not a pure flux limit Rencontres de Moriond J. Bartlett

  19. Numbers at high z Bartlett 2001 SPT: 4000 deg2 ~100s of Planck clusters at z>1 (unresolved) ~1000s of SPT clusters at z>1 Planck: 30000 deg2 Rencontres de Moriond J. Bartlett

  20. Photometry - SPTRelation Yrec - Ytrue • Small bias • Scatter: • Much larger than instrumental noise • Cluster-cluster confusion • Significantly larger than predicted intrinsic scatter Rencontres de Moriond APC U. Paris 7

  21. Photometry - AMIRelation Yrec - Ytrue Problem caused by inability to determine cluster core radius … … due to confusion with primary CMB anisotropy Requires follow-up in other wavebands Rencontres de Moriond APC U. Paris 7

  22. Conclusions - I Breakthrough at z>1: 10 --> 1000s • These new, large cluster catalogs will address key cosmological questions • Galaxy formation • Dark energy(e.g., Lima & Hu 2005, Wang et al. 2004) • SZ effect ideally suited for cluster surveying • Efficient at high z • Roughly uniform mass selection out to z>1 • Expectations 2006-2010: 10s => 1000s @ z>1 • Interferometers ~ 100 (~10% at z>1) • Bolometer cameras ~ 1,000 - 10,000 (~10% at z>1) • Planck ~10,000 all sky (~1% at z>1) Rencontres de Moriond J. Bartlett

  23. Conclusions - II • Studying catalog construction (Vale & White 2005, Pierpaoli et al. 2005, Melin et al. 2005, 2006) • Selection function • Point source confusion • Calibration • Simulations using rapid matched filter algorithm • Catalog selection criteria: Not Flux Limited • Photometry • Significant scatter • Single frequency compromised - need follow-up (e.g., 90GHz) Rencontres de Moriond J. Bartlett

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