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A Primer on SZ Surveys

A Primer on SZ Surveys. Gil Holder. Institute for Advanced Study. Outline. Sunyaev-Zel’dovich effect Upcoming surveys What’s next?. Optical Image of Cl 0016+16 (Clowe et al. 2000). ~ 7’. ~ 2 h -1 Mpc. Hot Gas in Cl 0016+16. (Reese). kT ~ 7.5 keV. Sunyaev-Zel’dovich Effect. I.

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A Primer on SZ Surveys

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  1. A Primer on SZ Surveys Gil Holder Institute for Advanced Study

  2. Outline • Sunyaev-Zel’dovich effect • Upcoming surveys • What’s next?

  3. Optical Image of Cl 0016+16(Clowe et al. 2000) ~ 7’ ~ 2 h-1 Mpc

  4. Hot Gas in Cl 0016+16 (Reese) kT ~ 7.5 keV

  5. Sunyaev-Zel’dovich Effect I Hot electrons CMB+ CMB  Optical depth: τ ~ 0.01 Fractional energy gain per scatter: ~ 0.01

  6. SZ Observables I Along a line of sight: DEPENDS ONLY ON CLUSTER PROPERTIES !!!! Independent of redshift Temperature weighted electron column density Unique spectral signature

  7. Non-Thermal Spectrum Abell 2163 Data from 3 experiments

  8. SZ Observables II Integrated effect from cluster: • proportional to total thermal energy of electrons • Temperature weighted electron inventory • angular diameter distance, not luminosity distance

  9. SZ Observables III In reasonable units ( i.e., 1/h): Assume a virial relation: uncertainties come in mass limit as ^(0.6)

  10. SZE Regularity Metzler ; astro-ph/9812295 dTo <dT> Average SZ flux vs Mass – 10% scatter Central decrement vs Mass – 40% scatter

  11. Searching for Galaxy Clusters Small area; very deep - AMI, AMIBA, BOLOCAM, SZA Large area; relatively shallow - ACBAR, PLANCK Large area; very deep - ACT, SPT

  12. Mass Limits Fluxes at 30 GHz PLANCK SZA

  13. Foregrounds • CMB – need good angular resolution and/or good spectral resolution; problem at all SZ frequencies • Radio point sources – need good angular resolution for frequencies <90 GHz • Dusty point sources – need good angular resolution and/or spectral resolution at frequencies >200 GHz • Radio halos and ghosts – could be a problem at frequencies < 15 GHz

  14. SZA • Survey 10 square degrees to a few uK at resolution of 2-3 arcminutes at 30 GHz • Expected mass limit ~ • Follow up catalog at 90 GHz for high resolution (<20”) • 100 – 500 clusters expected

  15. Example: RXJ1347-1145 Reese X-ray (colours) SZ only SZ (contours)

  16. CMB contamination?? • clusters are clearly at a different spatial scale • close amplitudes means beam dilution catches up fast !!! Roughly 1 deg x 1deg – labels are uK

  17. Cosmology With the SZA Holder, Haiman & Mohr 2001

  18. Dark Energy With the SZA • 12 square degrees • assume NO systematic errors • assume redshifts measured to z=2

  19. PLANCK • Survey the full sky to a few uK at resolution of 5-10 arcminutes at many frequencies • Expected mass limit ~ • Cluster detections will be unresolved – point sources with SZE-like spectra • 1000 – 50000 clusters expected

  20. Cosmology With Planck Black: all z Red: z<0.5 only Holder, Haiman & Mohr 2001

  21. SPT/ACT/??? • Survey ~1000 square degrees to a few uK at resolution of 1-2 arcminutes at several frequencies • Expected mass limit ~ • Most powerful for cosmology • 5000 – 200000 clusters expected

  22. Cosmology with the SPT Holder, Haiman & Mohr 2001

  23. dN/dz for SPT

  24. Dark Energy With the SPT Also sensitive to time dependent equation of state (Weller, Battye & Kneissl 2001)

  25. Possible Plan of Action • Use AMI/AMIBA/BOLOCAM/SZA to define a significant SZE-selected sample • Follow up at many wavelengths: optical, X-ray, radio, cm, mm (including SZA!) • Do a very large, deep survey for precise measurements of cosmological parameters

  26. On the Horizon uK imaging between 30-400 GHz with arcminute resolution -- SPT, ACT, dedicated interferometers, ALMA, etc. New science opportunities & challenges -- peculiar velocities, -- spectral SZ -- CMB lensing

  27. Peculiar Velocities (Kinetic SZ) • Pure redshift, blueshift => thermal spectrum Arcminutes scales => CMB ~ 1 uK -- CMB noise contribution = 10 km/s (0.01/τ) Other contamination: 50 km/s ? (Fischer & Lange 1993)

  28. Relativistic Corrections

  29. Lensing of the CMB Typical CMB gradient -- 15 uK/arcmin Typical deflection angle -- ~ 0.1-1 arcmin (Seljak and Zaldarriaga )

  30. Summary • New cluster surveys coming soon • Detailed follow-up will be required of some sample of SZE-selected clusters • Ambitious survey machines in proposal stages could be extremely powerful

  31. Gallery of SZ Images Z=0.83 Z=0.14

  32. Green: shift in matter density by 10% Holder & Carlstrom 2001

  33. Counting Galaxy Clusters Mass limit Mass function Volume element (Jenkins, Press-Schechter)

  34. Self-Similar Evolution Holder & Carlstrom 2001

  35. Effects of Gas Evolution Holder & Carlstrom 2001

  36. Angular Power Spectrum of SZ Sources Holder & Carlstrom 2001

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