Presentation is loading. Please wait.

Presentation is loading. Please wait.

The South Pole Telescope Galaxy Cluster Survey Joe Mohr Ludwig-Maximilians University Max Planck Insitute for Extraterrestrial Physics Munich SPT BCS e-ROSITA.

Similar presentations


Presentation on theme: "The South Pole Telescope Galaxy Cluster Survey Joe Mohr Ludwig-Maximilians University Max Planck Insitute for Extraterrestrial Physics Munich SPT BCS e-ROSITA."— Presentation transcript:

1 The South Pole Telescope Galaxy Cluster Survey Joe Mohr Ludwig-Maximilians University Max Planck Insitute for Extraterrestrial Physics Munich SPT BCS e-ROSITA z~1.3 kT~8.5keV

2  ( Sub) millimeter wavelength telescope:  At the South Pole  10 meter aperture  1’ FWHM beam at 150 GHz  20 micron RMS surface accuracy  5 arcsec astrometry  SZ Receiver:  1 sq. deg FOV  Observe in 3 bands between GHz simultaneously  Sensitivity ~ μ K- arcmin South Pole Telescope (SPT) 12 March 2012 Mohr - Moriond Cosmology

3 12 March 2012 Mohr - Moriond Cosmology John Carlstrom Steve Padin Stephan Meyer Clem Pryke Wayne Hu Andrey Kravtsov Brad Benson Clarence Chang Tom Crawford Will High Tom Plagge William Holzapfel Adrian Lee Martin White Sherry Cho Huan Tran Martin Lueker Jared Mehl Christian Reichart Dan Schwan Erik Shirokoff Oliver Zahn Joaquin Vieira Abbie Crites Ryan Keisler Lindsey Bleem Jonathan Stricker John Ruhl Tom Montroy Antony Stark Chris Stubbs Brian Stalder Mark Brodwin Jonathan Ruell Joe Mohr Gurvan Bazin Shantanu Desai Alex Saro Robert Suhada Sebastian Bocquet Jiayi Liu Alfredo Zenteno Matt Dobbs Gil Holder Jonathan Dudley Keith Vanderline Lloyd Knox Jason Dick Nils Halverson Erik Leitch Peter Ade Helmuth Spieler SPT Collaboration John Carlstrom, PI Jeff McMahon Jeeseon Song

4 And it actually works! Full Depth Solid Angle deg deg deg deg 2 Total Total 2491deg 2 12 March 2012 Mohr - Moriond Cosmology Candidates (21) (98) (146) (190) Total Total 777 (455) From: Keisler & Crawford 90GHz – 42  K-armin 150GHz – 18  K-armin 220GHz – 85  K-armin

5 SPT Optical Followup We examine DSS around each candidate We examine DSS around each candidate Image w/Medium aperture for z>0.5 Image w/Medium aperture for z>0.5 Blanco 4m, Magellan 6.5m, (SOAR, NTT) Image w/Small aperture for z<0.5 Image w/Small aperture for z<0.5 Swope 0.9m, ESO/MPG 2.2m We use multiband photometry to get red sequence cluster redshifts We use multiband photometry to get red sequence cluster redshifts We obtain Spitzer IRAC imaging for all candidates at S/N>4.8 We obtain Spitzer IRAC imaging for all candidates at S/N>4.8 NIR Imaging for any non- confirmation or z>0.9 NIR Imaging for any non- confirmation or z> March 2012 Mohr - Moriond Cosmology SPT-CL , z=1.08 SPT-CL , z=1.03 SPT-CL z=0.78 SPT-CL , z=0.61 SPT-CL , z=0.57 SPT-CL , z=0.39

6 Optical and IR Followup Team 0.3 – 4.5 μ m Harvard/CFA Chris Stubbs Matt Ashby Brian Stalder Ryan Foley Mark Brodwin (  U Missouri) Jonathan Ruel Armin Rest (  STScI) LMU Joe Mohr Gurvan Bazin Shantanu Desai Alfredo Zenteno Jiayi Liu Alex Saro Jeeseon Song (  U Michigan) Chile Alejandro Cocchliati Chicago Mike Gladders Lindsey Bleem Will High Davis Adam Stanford Florida Anthony Gonzalez Leiden Henk Hoekstra Tim Schrabback (  Bonn) Goals: confirmation, redshift measurement, mass measurement

7 Photometric Redshifts Two sub-teams work pseudo independently to provide a crosscheck Two sub-teams work pseudo independently to provide a crosscheck We calibrate photometry using the distribution of stars in color- color space (stellar locus) We calibrate photometry using the distribution of stars in color- color space (stellar locus) See High et al 2009 for overview See High et al 2009 for overview Spectroscopic followup program has allowed good cross-checks, and photo-z performance is good Spectroscopic followup program has allowed good cross-checks, and photo-z performance is good Characteristic accuracy is ~0.025(1+z) Characteristic accuracy is ~0.025(1+z) 12 March 2012 Mohr - Moriond Cosmology Song et al 2012

8 12 March 2012 Mohr - Moriond Cosmology 2012 SPT Cluster Sample – Followup Status At present we are followup limited At present we are followup limited We have observed ~500 clusters (out of full sample of 777 candidates) We have observed ~500 clusters (out of full sample of 777 candidates) Runs scheduled this summer at SOAR and the ESO/MPG 2.2m Runs scheduled this summer at SOAR and the ESO/MPG 2.2m We will submit proposals to complete the followup of the sample this fall We will submit proposals to complete the followup of the sample this fall Expect followup of full sample (~550 clusters) to be complete next year Expect followup of full sample (~550 clusters) to be complete next year Meanwhile, we have a subsample of 750 deg 2 where followup is complete Meanwhile, we have a subsample of 750 deg 2 where followup is complete SPT survey data SPT survey data 224 candidates at S/N> candidates at S/N>4.5 This allows us the first look at a large sample of SPT selected clusters This allows us the first look at a large sample of SPT selected clusters 8

9 12 March 2012 Mohr - Moriond Cosmology SPT Clusters in 750 deg 2 Followup-Complete Region: Contamination Contamination Contamination Filtered CMB maps exhibit Gaussian noise. Easy to calculate density of noise peaks at >4.5 , >5  Filtered CMB maps exhibit Gaussian noise. Easy to calculate density of noise peaks at >4.5 , >5  Together with cluster S/N distribution one can estimate contamination fraction Together with cluster S/N distribution one can estimate contamination fraction Sims: 5), ~25% (S/N>4.5) Sims: 5), ~25% (S/N>4.5) Measurements-> agree Measurements-> agree SPT-only selection produces >95% pure sample at S/N>5 SPT+optical followup produces ~100% pure sample at S/N>4.5 Song et al 2012

10 12 March 2012 Mohr - Moriond Cosmology SPT Clusters in 750 deg 2 Followup-Complete Region: BCG-SPT Positional Offsets Statistics of SPT and Brightest Red Cluster Galaxy positions Statistics of SPT and Brightest Red Cluster Galaxy positions 68% at  <34” 68% at  <34” 95% at  <78” 95% at  <78” 99% at  <132” 99% at  <132” The distribution of BCGs within the virial region is relatively broad The distribution of BCGs within the virial region is relatively broad Consistent with statistical uncertainties for SPT positions Consistent with statistical uncertainties for SPT positions BCG distribution for SPT clusters is consistent with that from nearby X-ray selected cluster sample BCG distribution for SPT clusters is consistent with that from nearby X-ray selected cluster sample (e.g. Lin & Mohr 2004 => 70% within 5% of r 200 ) No clear evidence of redshift evolution No clear evidence of redshift evolution (e.g. Fassbender et al 2011) Song et al 2012

11 12 March 2012 Mohr - Moriond Cosmology SPT Clusters in 750 deg 2 Followup-Complete Region: Redshift Distribution Statistics of 750 deg 2 sample Statistics of 750 deg 2 sample 224 candidates 224 candidates 158 with measured photo-z’s 158 with measured photo-z’s Median redshift is ~0.54 Median redshift is ~ % of sample at z>0.8 18% of sample at z>0.8 High-z massive SPT clusters are unique population High-z massive SPT clusters are unique population M 200 >4x10 14 M o even at highest z M 200 >4x10 14 M o even at highest z Large solid angle survey (2500 deg 2 ) allows us to find very rare objects Large solid angle survey (2500 deg 2 ) allows us to find very rare objects ~100 of these clusters over full survey ~100 of these clusters over full survey Song et al 2012

12 Rarest, Most Massive Clusters In late 2010 SPT finished shallow “preview” scans of the full 2500deg 2 In late 2010 SPT finished shallow “preview” scans of the full 2500deg 2 Adequate to select the 26 most massive clusters, independent of redshift Adequate to select the 26 most massive clusters, independent of redshift Mortonson analysis suggests no single cluster in tension with  CMD Mortonson analysis suggests no single cluster in tension with  CMD Constraints on non-Gaussianity parameter f NL =20+/-450 from Likelihood analysis over full sample Constraints on non-Gaussianity parameter f NL =20+/-450 from Likelihood analysis over full sample More precise statements require improved mass knowledge and analysis of the low mass/high-z portion of the sample More precise statements require improved mass knowledge and analysis of the low mass/high-z portion of the sample 12 March 2012 Mohr - Moriond Cosmology Williamson et al 2011

13 Cluster Mass Calibration To take advantage of the ~550 cluster sample, we need to push the mass calibration below the 5% level To take advantage of the ~550 cluster sample, we need to push the mass calibration below the 5% level Redshift evolution os mass-obs relation Redshift evolution os mass-obs relation Full S/N range Full S/N range Multi-wavelength, staged approach Multi-wavelength, staged approach First use X-ray to leverage existing calibrations First use X-ray to leverage existing calibrations Meanwhile bring in direct calibration from weak lensing (and velocity dispersions) Meanwhile bring in direct calibration from weak lensing (and velocity dispersions) Also, extend mass calibration to FULL sample (not just highest mass subset) Also, extend mass calibration to FULL sample (not just highest mass subset) 12 March 2012 Mohr - Moriond Cosmology Andersson et al 2011

14 Challenges with Mass Calibration X-ray Mass calibration X-ray Mass calibration Currently relies on hydrostatic mass assumption Currently relies on hydrostatic mass assumption Measurements at low z (risky for SPT) Measurements at low z (risky for SPT) Low scatter mass proxies useful Low scatter mass proxies useful Weak lensing mass calibration Weak lensing mass calibration Direct calibration in combination with sims Direct calibration in combination with sims SPT Program SPT Program Magellan Megacam, HST+VLT (14 clusters at z>0.6) Magellan Megacam, HST+VLT (14 clusters at z>0.6) DES dataset -> stacked lensing DES dataset -> stacked lensing Velocity dispersion mass calibration Velocity dispersion mass calibration Direct calibration in combination with sims Direct calibration in combination with sims Detailed study of merging, selection Detailed study of merging, selection SPT Program SPT Program ~80 clusters with Gemini at z<0.8 ~80 clusters with Gemini at z<0.8 ~40 clusters at higher redshift with VLT/FORS2 ~40 clusters at higher redshift with VLT/FORS2 12 March 2012 Mohr - Moriond Cosmology Saro et al 2012

15 Summary SPT cluster survey to 18  K-armin over 2500 deg 2 complete SPT cluster survey to 18  K-armin over 2500 deg 2 complete Optical/NIR followup effort to measure redshifts and remove contamination will finish over the next year Optical/NIR followup effort to measure redshifts and remove contamination will finish over the next year Final sample will be ~450 clusters at S/N>5, ~550 clusters at S/N>4.5 Final sample will be ~450 clusters at S/N>5, ~550 clusters at S/N>4.5 SPT-only selection has low contamination (~5% at S/N>5, ~25% at S/N>4.5) SPT-only selection has low contamination (~5% at S/N>5, ~25% at S/N>4.5) SPT+optical followup sample has extremely high purity (~100%) SPT+optical followup sample has extremely high purity (~100%) Rare, Massive Clusters at High Redshift Rare, Massive Clusters at High Redshift Uniform selection with mass (~independent of redshift) over large solid angle – opens new window on rare, massive clusters at high z Uniform selection with mass (~independent of redshift) over large solid angle – opens new window on rare, massive clusters at high z Expect ~100 clusters at z>0.8 with M 200 >4x10 14 M o Expect ~100 clusters at z>0.8 with M 200 >4x10 14 M o Bottom line: no cosmological surprises so far Bottom line: no cosmological surprises so far Thing to watch: Improving mass calibration, new very high z systems Thing to watch: Improving mass calibration, new very high z systems Mass calibration effort using X-ray, dispersions and weak lensing underway- will take a while! Mass calibration effort using X-ray, dispersions and weak lensing underway- will take a while! 12 March 2012 Mohr - Moriond Cosmology


Download ppt "The South Pole Telescope Galaxy Cluster Survey Joe Mohr Ludwig-Maximilians University Max Planck Insitute for Extraterrestrial Physics Munich SPT BCS e-ROSITA."

Similar presentations


Ads by Google