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ONE MILLION GALAXIES

ONE MILLION GALAXIES. Cosmography and Cosmology. Michael S. Vogeley Department of Physics Drexel University. Quantitative Large-Scale Structure: Lick Survey. 1 million galaxies! Lick observatory plates Counts by eye (Shane-Wirtanen), map by Seldner et al. 1977

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ONE MILLION GALAXIES

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  1. ONE MILLION GALAXIES Cosmography and Cosmology Michael S. Vogeley Department of Physics Drexel University XXXVth Recontres de Moriond, Energy Densities in the Universe

  2. Quantitative Large-Scale Structure: Lick Survey 1 million galaxies! Lick observatory plates Counts by eye (Shane-Wirtanen), map by Seldner et al. 1977 Analyses by Peebles, Groth, and Fry, et al. Angular correlation functions: 2, 3, 4-pt Groth & Peebles (1977) Michael S. Vogeley, Drexel University

  3. Hints of Greatness: The Shift to 3D The Photon-Counting Cowboys KOSS (1981): 50 Mpc/h Void in Bootes Anomalous? Truly empty? Formation mechanism? Center for Astrophysics (1982): Power-law 3D correlations Pairwise velocity dispersion Predict gravity field Comparison with N-body sim’s “Frothy…filamentary superclusters” Kirshner et al. (1981) Davis & Peebles (1983) Michael S. Vogeley, Drexel University

  4. Voids, Walls, and Peaks: Death to CDM? CfA slice(1986), CfA2, SSRS: Structures as large as survey Voids fill space P(k) rules out SCDM APM galaxy catalog (1990): Too much large-scale power for SCDM BEKS pencil-beams (1990): 128 Mpc/hPeaks in 1D P(k) Characteristic scales in LSS? Geller & Huchra (1988) Maddox et al. (1990) Michael S. Vogeley, Drexel University

  5. All-Sky: The IRAS z Surveys IRAS 2Jy (1989), 1.2Jy (1993) QDOT (1991), PSCz 0.6Jy (1999) Selection of galaxies independent of photo plates, Galactic extinction IR-selected trace same structures with lower density in clusters Similar statistics, but lower clustering amplitude Clear evidence for biasing on all scales All-sky benefits: spherical window density-velocity study Saunders et al. (2000) Michael S. Vogeley, Drexel University

  6. CCD-Based Surveys and the Era of Multiplexing Shectman et al. (1996) Las Campanas Redshift Survey: R-band CCD driftscan photometry 100 Fiber-fed spectrograph Ubiquitous voids and walls - the end of “greatness”? Peak in the 2D power spectrum near same scale as BEKS Limited by geometry What if we survey the whole sky? Landy et al. (1996) Michael S. Vogeley, Drexel University

  7. Current Status on Large-Scale Structure • What drives structure formation? • Gravity! • Cosmological parameters? • Components of mass-energy density? • Baryon fraction (?), CDM, HDM?, what else? • Is the cosmological “constant” constant? • Galaxy formation: connecting mass to light • Gastrophysics and biasing Michael S. Vogeley, Drexel University

  8. Critical Issues for Large-Scale Structure • Features in P(k) at peak scale and beyond • Is the peak too sharp? • Wiggles in the spectrum? • Structure on Gpc scales? • Messy details about galaxies • Galaxy segregation (“biasing”) • Galaxy evolution (purely local?) • Voids: Are they too empty? Vogeley (1999) Blanton et al. (1999) Michael S. Vogeley, Drexel University

  9. Features in the 3D Power Spectrum Baryonic Wiggles Eisenstein & Hu (1998) LSS+CMB Gawiser & Silk (1998) Slope agreement at small scale Linear to non-linear transition Feature at 0.1-0.2h/Mpc Peak at 0.03-0.04h/Mpc Slope, ampl <0.03? Physics on peak scale? LSS vs. CMB Michael S. Vogeley, Drexel University

  10. Voids and Void Galaxies De Lapparent, Geller, & Huchra (1986) Cen & Ostriker (1998) Data vs. N-body+hydro: sim voids too empty? Data vs. N-body+SAMs: sim void edges not sharp? Galaxy evolution at Need color, spectra, low SB, mag range Diaferio et al. (1999) Michael S. Vogeley, Drexel University

  11. Photometry Large area Consistent, accurate calibration Galactic extinction Spectroscopy Large depth Complete sampling Careful target selection Multi-wavelength Surface-brightness Resolve features Wavelength range Desiderata for New Galaxy Surveys Observational Systematics Measured Galaxy Properties Michael S. Vogeley, Drexel University

  12. A Survey of Surveys Colless (1999) Vogeley (1999) Michael S. Vogeley, Drexel University

  13. Volume and Number Surveyed Michael S. Vogeley, Drexel University

  14. www.sdss.org Michael S. Vogeley, Drexel University

  15. Features of the SDSS Unique 2.5m telescope, located at Apache Point, NM 3 degree diameter field of view Two surveys in one: Photometric survey in 5 bands Spectroscopic redshift survey CCD Mosaic Camera 30 CCDs 2K x 2K (imaging) 22 CCDs 2K x 400 (astrometry) Two double spectrographs 2 x 320 fibers (3 arcsec diameter) resolution  / =2000 Spectral coverage from 3900Å to 9200Å Automated data reduction Over 70 man-years of development effort (Fermilab + collaboration scientists) Very high data volume 40 TB of raw data About 1 TB of catalog data Data made available to the public Michael S. Vogeley, Drexel University

  16. SDSS: The Photometric Survey Northern Galactic Cap drift-scan imaging of 10,000 square degrees 5 broad-band filters pixel size is 0.4 arcsec > 800 billion pixels x 5 filters 20 TB raw imaging data  pipeline 100,000,000 galaxies 50,000,000 stars Southern Galactic Cap multiple scans (> 30 times) of one stripe another 20 TB of raw imaging data detect fainter, variable, and moving objects Continuous data rate of 8 Mbytes/sec Michael S. Vogeley, Drexel University

  17. The First Stripes: 600 sq.deg. done, 9400 to go! Camera: 5 color imaging of 600 square degrees Multiple scans across the same fields Photometric limits as expected PSF variations taken out in software Michael S. Vogeley, Drexel University

  18. SDSS: The Spectroscopic Survey Spectroscopic targets: 1 million galaxies (main + BRG) 100,000 quasars 100,000 stars selected objects from other catalogs Two high-throughput spectrographs spectral range 3900-9200 Å 640 spectra simultaneously resolution  / =2000 Automated reduction of spectra redshift spectral features classification The result: A redshift map to z=0.2 and beyond Michael S. Vogeley, Drexel University

  19. Status Report on SDSS Spectroscopy 12 plug-plate fields Both spectrographs fully operational >7,000 test spectra at survey spec. Measured throughput: 15%,20% Redshift completeness: 98% r’=18 galaxy z=0.19 Michael S. Vogeley, Drexel University

  20. Discovery of the Highest-Redshift Quasars Eight of the ten highest redshift quasars have been found in the first SDSS test data Michael S. Vogeley, Drexel University

  21. Finding Rare Objects Distant QSO’s are outliers in color-color space The SDSS analysis pipeline automatically discovers candidate objects for spectroscopic followup Michael S. Vogeley, Drexel University

  22. SDSS Commissioning-Data Science High-z quasars Methane, L dwarfs Structure of Galactic halo with RR Lyrae Galaxy-galaxy weak lensing Magnification bias from lensing Clusters of galaxies, X-ray sources Compact groups of galaxies and correlations Angular correlations of galaxies IR, FIRST sources Quasar-galaxy cross-correlations Carbon stars QSO absorption line systems Galaxy-galaxy lensing detected in 1/44 of SDSS Fischer et al. (1999) Michael S. Vogeley, Drexel University

  23. SDSS 2.5m Observation Schedule May 1998 - March 1999 First light imaging - equatorial only Camera and software commissioning April 1999 Telescope pointing model Great circle scan tests Spectrograph flexure tests May 1999 Spectrograph testing Great circle driftscan imaging June 1999 First astronomical spectroscopy Fall 1999 Spectroscopic commissioning Target selection tests March 2000 Survey proper begins Michael S. Vogeley, Drexel University

  24. Outlook: A Golden Age for Structure Formation* Independent probes of structure out to 1Gpc High-resolution power spectra Sampling the same wavelength scales at z=0, 1000 Multi-variate distribution of galaxies Photometric, spectroscopic properties Evolution of populations Segregation and “biasing” Multi-wavelength data bases Integration of X-ray, UV, Optical, IR, Radio surveys On-line digital data access Data mining methods * “You fool, there were no good old days. You’ve simply romanticized the agony of freezing all night in the prime-focus cage.” - F. Zwicky (perhaps) Michael S. Vogeley, Drexel University

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