PISCO Progress. Antony A. Stark, Christopher Stubbs Smithsonian Astrophysical Observatory 20 March 2009

Transcription

1 PISCO Progress Antony A. Stark, Christopher Stubbs Smithsonian Astrophysical Observatory 20 March 2009

2 PISCO Overview South Pole Telescope Survey is underway: 200 square degrees observed so far, 1000 square degrees by end of previously-unknown clusters of galaxies have been detected at a level > 5σ Of these, 16 have been optically confirmed, 12 by LDSS3 and IMACS, 4 in Blanco Cluster Survey All attempted optical confirmations have so far been positive. PISCO on-track for completion by 1 October 2009 (assuming all goes well)

3 South Pole 10m Telescope (SPT) A Brief Progress Report

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6 Slide: Kathryn Miknaitis

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8 The South Pole Telescope, January 2007

9 Sunyaev-Zel dovich Effect Adapted from L. Van Speybroeck

10 Spectrum of S-Z effect South Pole Telescope has bands at 90 GHz, 150 GHz, and 220 GHz. Cluster signature: negative feature at 90 GHz and 150 GHz, and null detection at 220 GHz. Spurious cluster detections should be < 1% of all cluster detections. Black = non-relativistic Blue = relativistic Cluster detection efficiency is essentially independent of redshift.

11 Sunyaev-Zel dovich Effect signature is independent of redshift Powerful and Unique Cosmological Probe SZE SURVEYS SZE contours 75 uk for each panel; X-ray insets with same intensity scale

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13 SPT-SZ Survey SPT will find thousands of clusters of galaxies Most will have core radius ~ 1 arcminute Richness information from depth of SZ signature No redshift information Timescale: 200 square degrees finished so far 1000 square degrees to be finished by September 2010 Additional 4000 square degrees at higher sensitivity proposed Clusters approach to Dark Energy is complementary to Supernovae method SZ, X-ray data from clusters may be comprehensible from first principles, and strongly constrain cosmological parameters in ways that are orthogonal to other methods

14 100 square degrees Surveyed at 150 GHz by South Pole Telescope to an rms noise level of about 25 µk. This map required about 2 weeks of observing time. Note presence of point sources (quasars), cosmic microwave background anisotropy, and small negative features (clusters). The South Pole Telescope is working to proposed specifications.

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16 2008 data 100 sq. deg. 5h30m field 22 detected cluster Positions shown

17 Data from previous slide With 1 arcmin cluster-finding filter applied

18 Examples of Magellan Confirmation of SPT-detected Clusters Magellan g, r, i, z images with contours of Sunyaev-Zel dovich σ from SPT

19 Parallel Imager for Southern Cosmology Observations (PISCO): A Multiband Imager for Magellan Antony Stark Christopher Stubbs Matt Holman John Geary Andy Szentgyorgyi Steve Amato Michael Wood-Vasey Will High Andrea Loehr Brian Stalder James Battat Armin Rest Steve Sansone Smithsonian PI Harvard PI Smithsonian Planets, exoplanets CCD electronics Design consultant CCD electronics Astronomer Observing Thesis project, Harvard Physics Astronomer Observing algorithm PostDoc,, Harvard Physics grad student, SAO PostDoc Photo-z z Software LPPC machine shop

20 PISCO System Characteristics Optical Passbands g, r, i, z simultaneous imaging Plate Scale Field of View Detectors Readout time 0.16 arcsec per 10 micron pixel 9 arcmin across diagonal (corresponds to 2.4 Mpc at z=0.3) One MIT Lincoln Labs 3K x 6K CCD per focal plane Read noise < 4 e rms (cf. Stubbs talk) Optimal AR coating for each passband Deep depletion CCDs for i, z bands < 25 seconds 80% encircled energy radius < 0.2 arcseconds (seeing limited) Optical surfaces All spherical, 8 inch diameter or smaller lenses.

21 PISCO Design Concept Small Guider Housing Cable Wrap Shutter ADC Dewar Wall Lenses Dichroics & CCDs Electronics mounted here

22 Construction Progress Dichroic cubes are finished, meet specs All glass blanks have been delivered RFQ for lens grinding in progress Electronics, CCDs are finished, tested Dewar, instrument mechanics are in progress, some parts already made Data reduction pipeline trial run has been successfully completed on LDSS3

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24 Potential Constraints on Dark Energy South Pole 10m cluster survey M lim =4.9x10 14 M o over 4x10 3 deg 2 ~17,000 clusters detected Statistical uncertainties on w and Ω E Ω E to 0.01 <w> to 0.05 Marginalized over σ 8 Important factors not included: Non-flat geometries 10% uncertainty in H o (20% broadening) Cosmic variance Systematic uncertainties

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