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The Growth of LSS in a Dark Energy Dominated Universe

The Growth of LSS in a Dark Energy Dominated Universe. Marc Davis UC Berkeley. The DEEP2 Galaxy Redshift Survey used the DEIMOS spectrograph at the Keck II telescope to study both galaxy properties and large-scale structure at z~ 1. The DEEP2 Collaboration. Other Institutions

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The Growth of LSS in a Dark Energy Dominated Universe

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  1. The Growth of LSS in a Dark Energy Dominated Universe Marc Davis UC Berkeley Texas A&M, May 2007

  2. The DEEP2 Galaxy Redshift Survey used the DEIMOS spectrograph at the Keck II telescope to study both galaxy properties and large-scale structure at z~1. The DEEP2 Collaboration Other Institutions J. Newman (LBNL) A. Coil (Arizona) C. Willmer (Arizona) B. Weiner (Arizona) R. Schiavon (UVA) C. Conroy (Princeton) N. Kaiser (Hawaii) D. Finkbeiner (Harvard) A. Connolly (Pitt.) U.C. Santa Cruz D. Phillips S. Kassin K. Noeske A. Metevier L. Lin N. Konidaris G. Graves J. Harker U.C. Berkeley M. Davis (PI) D. Croton M. Cooper B. Gerke R. Yan U.C. Santa Cruz S. Faber (Co-PI) D. Koo P. Guhathakurta

  3. DEEP2 has been made possible by DEIMOS, a new instrument on Keck II • DEIMOS: • PI: Faber • wide-field multiplexing (up to 160 slitlets over a 16’x4’ field) • high resolution (R~5000) • spectral range (~2600 Å at highest resolution) • CCD array of 8k x 8k Texas A&M, May 2007

  4. DEEP2 pre-selects high-z galaxies using observed colors Texas A&M, May 2007

  5. DEEP2 mask selection Targeted galaxies are enclosed with white curves Solid slits are objects selected on a given mask. dotted and dashed lines are galaxies from neighboring masks.

  6. DEEP2 slitmask spectroscopy l position Using custom-milled slitmasks with DEIMOS we obtained spectra of ~150 targets at a time. A total of 400 slitmasks was required for the survey; we tilted slits up to 30 degrees to obtain rotation curves. Texas A&M, May 2007

  7. DEEP2/CFHT B,R,I GALEX NUV+FUV Chandra & XMM: XMM Chandra (1.6Ms) AEGIS:the All-wavelength Extended Groth Strip International Survey Spitzer MIPS, IRAC DEEP2 spectra and Caltech/JPL Ks imaging HST/ACS V,I (Cycle 13) Plus VLA (6 & 21 cm), SCUBA, etc…. Texas A&M, May 2007

  8. X-ray analysis - detection and photometry • P.Nandra et al. • Each square has integration time of 200 ksec • Source selection and photometry by own method • Elliptical shaped PSFs • All data will be released in August, 2007 1.6 Ms Texas A&M, May 2007

  9. A Redshift Survey at z=1: • 3 sq. degrees • 4 fields (0.5o x <2o) • 80 Keck nights, one-hour exposures to RAB=24.1 • primarily z~0.75-1.4 (pre-selected using BRI photometry) • 46,585 unique redshifts, error ~30 km/s • ~5·106 h-3Mpc3 • 1200 l/mm: ~6500-9200 Å • 1.0” slit: FWHM 68 km/s • z=0.7-1.4 spans lookback time ~6.0 - 8.0 Gyr ago • Within DEEP2 we are surveying 2.5 Gyr or ~20% of the history of the Universe, and SDSS/2dF comparisons give ~3x this baseline Texas A&M, May 2007

  10. Redshift Distribution of DEEP2 Survey Texas A&M, May 2007

  11. DEEP2 Status Update • DEEP2 began observations in July 2002. • Observations are now >95% finished, with >49k spectra in hand and 3 of 4 fields completed. • Follow-up observations have begun. • First season’s data is already public: • http://deep.berkeley.edu/DR1 • Next data release (DR2) includes ~75% of the data and has also been released! http://deep.berkeley.edu/DR2 Texas A&M, May 2007

  12. Redshift Maps in 4 Fields: z=0.7-1.3 Cone diagram of 1/12 of the full DEEP2 sample Texas A&M, May 2007

  13. position l, z Galaxy groups in DEEP2 • Overdensities identified in redshift space. • Use the VDM algorithm of Marinoni et al. (2002). • Group in early DEEP2 data s~250 km/sec Texas A&M, May 2007

  14. DEEP2 Group Catalog Groups with >350 km/s Shown are groups for 3 fields --length of ellipse proportional to velocity dispersion Texas A&M, May 2007 Gerke et al. 2005,astro-ph/0410721

  15. Real Groups/Mock Groups galaxies shown in 3 projections x-r redshift plot y-r redshift plot Real or Mock??? X-y projected on sky Texas A&M, May 2007

  16. Apparent abundance of groups: dN(s,z)/dzds • Provides a useful test of dark energy eq. of state (Newman et al, 2002) • differences in the volume element varies by 3x between w=0 and w=-1 • For groups of modest-mass, the evolution of dispersion is 2nd order Why search for groups in DEEP2? • Heavy black curve is T=.3DEIMOS took ~7 years to build; at time of designing science expt. T was still undetermined, and DE was not discussed.

  17. Size of the Universe versus w

  18. Abundance versus Redshift Simulated Data!!

  19. Measured dispersion with galaxies compared to reality-- tremendous scatter!

  20. Dispersion with galaxies Texas A&M, May 2007

  21. Constraints expected on parameters w, 8, m Texas A&M, May 2007

  22. DEEP2 Cluster Counts DEEP2 survey counted ~300 groups Velocity dispersion measured in each case Counts of N(, z) is a strong test of w B. Gerke will have results out “soon”

  23. Conclusions on DEEP2 • DEEP2 observations are >96% done • DR2 has occurred in January:http://deep.berkeley.edu/DR2 • AEGIS ApJL special issue • Way too many new results to cover in one talk! Texas A&M, May 2007

  24. By combining area with depth, AEGIS allows us to study rare objects in detail… B. Gerke, JN et al. 2006, AEGIS ApJL, Accepted Texas A&M, May 2007

  25. Like a spectroscopically identified, dual AGN at z=0.7 Hb [OIII] 4959 [OIII] 5007 position l/ z Texas A&M, May 2007

  26. HST reveals a fairly-normal early-type host Texas A&M, May 2007

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