BigBOSS. Mapping the Universe

Transcription

1 BigBOSS Mapping the Universe

2 BigBOSS Stage IV BigBOSS designed to measures dark energy from the BAO standard ruler 1. Spectroscopic survey of 20 million galaxies at 0 < z < Spectroscopic survey of 600k QSOs at 2.2 < z < 3.5 Definitive BAO experiment at 0 < z < 1.5 Inflation probe exceeding reach of Planck satellite Galaxies 10X volume of BOSS More linear modes; full power not yet explored QSOs 2

3 BOSS: Ground-Based Stage III BAO Experiment 2006 White paper 2007 Telescope proposal Construction Data! BigBOSS: Ground-Based Stage IV BAO Experiment 2009 White paper 2010 NOAO proposal R&D and Construction Data! Timeline = DES + 5 years 3

4 NOAO telescope call Nov 18, 2009 NOAO > KPNO Home Announcement of Opportunity for Large Science Programs Providing New Observing Capabilities for the Mayall 4m Telescope on Kitt Peak NOAO announces an opportunity to partner with NOAO and the National Science Foundation to pursue a large science program with the Mayall 4-meter telescope on Kitt Peak and to develop a major observing capability (instrument, software, and archival plans) for the Mayall 4-meter telescope of the Kitt Peak National Observatory for the purpose of enabling large, high impact science programs and improving the capabilities provided as part of the U.S. System of ground-based optical and near-ir telescopes. Projects that use a diverse range of observing requirements (e.g. time of year, lunar phase, etc.) are encouraged. The dual goals of the large science program, as discussed in a recent edition of NOAO Currents are to enable frontier science and to improve the U.S. system of ground-based ØIR facilities. Although there are no restrictions on the type or scale David Schlegel of instrument, NOAO encourages proposals that will build 4 on the Mayall telescope s strengths, utilizing its unique wide-field capabilities. NOAO has investigated potential

5 BigBOSS proposal submitted Oct 1, 2010 A Proposal to NOAO for the BigBOSS Experiment at Kitt Peak National Observatory October 1, 2010 D. Schlegel p, F. Abdalla z, C. Ahn g, C. Allende-Prieto j, J. Annis h, E. Aubourg a, M. Azzaro i, C. Baltay ii, C. Baugh f,c.bebek p,s.becerril i, M. Blanton s, A. Bolton gg, B. Bromley gg, R. Cahn p, P.-H. Carton c, Y. Chu ff, M. Cortês p,x, K. Dawson gg, A. Dey r, H. T. Diehl h,p.doel z, A. Ealet d,j.edelstein x,d.eppelle c,s.escoffier d, A. Evrard cc, L. Faccioli p,x,c.frenk f,m.geha ii,d.gerdes cc, P. Gondolo gg, A. Gonzolez-Arroyo m, B. Grossan x, T. Heckman n, H. Heetderks x, S. Ho p, K. Honscheid u, D. Huterer cc, O. Ilbert o, I. Ivans gg,p.jelinsky x, Y. Jing v,s.kent h,d.kieda gg,c.kim g,j.-p.kneib o, X. Kong ff, A. Kosowsky dd, K. Krishnan g, O. Lahav z, M. Lampton x, S. LeBohec gg, V. Le Brun o, M. Levi p, H. Lim g, E. Linder g,x, W. Lorenzon cc, Ch. Magneville c, R. Malina o, C. Marinoni e, V. Martinez t,s.majewski hh, P. McDonald p,t.mckay cc, J. McMahon cc, B. Menard n, J. Miralda-Escude l, M. Modjaz s, N. Mostek p,x, J. Newman dd, R. Nichol ee, P. Nugent p,x,k.olsen r, N. Padmanabhan ii, I. Park g, J. Peacock aa, W. Percival ee, S. Perlmutter p,x, C. Peroux o, P. Petitjean k, F. Prada i,e.prieto o, J. Prochaska y,k.reil w, C. Rockosi y, N. Roe p, E. Rollinde k, A. Roodman w, N. Ross p,g.rudnick bb, V. Ruhlmann-Kleider c,c.schimd o,m.schubnell cc, R. Scoccimaro s, U. Seljak g,p,x, H. Seo x, M. Sholl x, R. Shulte-Ladbeck dd, A. Slosar b, G. Smoot g,p,x, W. Springer gg, A. Stril p, A. Szalay n, C. Tao d, G. Tarlé cc, E. Taylor x, A. Tilquin d,j.tinker s, J. Wang ff, T. Wang ff, B. A. Weaver s,d.weinberg u,m.white p,x, M. Wood-Vasey dd, J. Yang g, Ch. Yèche c, N. Zakamska n, A. Zentner dd, C. Zhai ff, P. Zhang v a Astrophysique, Particules et Cosmologie Laboratoire (APC), Paris b Brookhaven National Laboratory c CEA/IRFU, Saclay d Centre de Physique des Particules de Marseille e Centre de Physique Theorique, Université de Marseille f Durham University g Ewha Womans University, Korea h Fermi National Accelerator Laboratory David Schlegel 5 i Full text at

6 Institutions on BigBOSS Proposal Brookhaven National Laboratory Ewha Womans University, Korea Fermi National Accelerator Laboratory French Participation Group APC, IAP- Paris; CPP, CPT, LAP Marseille; CEA, IRFU Saclay Johns Hopkins University Lawrence Berkeley National Laboratory National Optical Astronomy Observatory New York University The Ohio State University Shanghai Astronomical Observatory SLAC National Accelerator Laboratory Spanish Participation Group IAA, Granada; IAC, Tenerife; ICC, Barcelona; IFT, Madrid; U. Valencia UK Participation Group Durham, Edinburgh, UC London, Portsmouth University of California, Berkeley University of Kansas University of Michigan University of Pittsburgh University of Science and Technology of China University of California, Santa Cruz/Lick Observatory University of Utah Yale University David Schlegel 6

7 The proposal contains: Construct BigBOSS instrument: 3 deg diameter FOV prime focus corrector 5000 fiber positioner 10x3 spectrographs, ,600 Ang Conduct BigBOSS Key Project 500 nights at Mayall 4-m 14,000 deg 2 survey 50,000,000 spectra 20,000,000 galaxy redshifts Every QSO in the universe, incl. 600,000 at z>2.2 David Schlegel 7

8 BigBOSS Science Goals BAO z=0 3.5 near cosmic-variance limit (design req.) RSD (redshift-space distortions) z=0 3.5 Neutrino masses Galaxy density map for weak lensing Detect non-gaussianity, use low-b + high-b sources BigBOSS Design Philosophy Optimize for z s only Simple design high throughput Full-sky David Schlegel 8

9 BigBOSS target selection The easy target survey Luminous Red Galaxies (LRGs) at 0 < z < 0.9 Emission-Lines Galaxies (ELGs) at 0 < z < 1.7 QSOs at 0 < z < 3.5 with dense Ly-alpha absorption maps at z > 2.2 Detectable to z=1.7 9

10 BigBOSS Stage IV BOSS near cosmic-variance limit at z < 0.7 BigBOSS near cosmic-variance limit to z=1.5 BigBOSS galaxy P(k) BAO cosmic variance limit per Δz=0.2 over 10,000 deg H(z) da BOSS BigBOSS courtesy Nikhil Padmanabhan 10

11 BigBOSS science reach BigBOSS angular distance precision -- 24,000 deg 2 Better than space at z < 0.7 using LRGs Better than space at z > 2 using LyAF cosmic variance cosmic variance Pat McDonald and Bob Cahn 11

12 BigBOSS science reach BigBOSS growth rate precision -- 24,000 deg 2 Pat McDonald and Bob Cahn 12

13 Kitt Peak 4-m (Mayall) 5000 fiber positioners on 1-m focal plane, f/4.5 BigBOSS instrument Corrector lenses 3 FOV SDSS-inspired: simple, high-throughput bare fibers! 5000 fibers 10 spectrographs X 3 channels each

14 BigBOSS collaboration expertise Partners are experienced (Current commitments only to R&D) USTC (China): Fiber positioners LAMOST fiber positioners IAA (Spain): Focal plane GTC Nasmyth mount + positioner design Fermilab (U.S.): Telescope top-end + lens cell UCL (U.K.): Telescope optics Dark Energy Survey top-end + optics (at sister telescope!) Yale: fiber view camera /QUEST U Michigan: calibration hardware /JDEM SLAC, Ohio State: data acquisition + guiding BOSS, DES, LSST NOAO: telescope interface, operations IEU (Korea): Fiber testing Fibers for other physics exp ts LAM + CPPM (France): Spectrographs VIMOS spectrographs CEA (France): Cryo systems Megacam cryo Berkeley Lab (U.S.): CCDs + electronics, optical design, project management JDEM optical design DES, BOSS, JDEM detectors 14

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17 BigBOSS instrument: corrector Prime Focus Corrector has eight elements (four corrector, four ADC/corrector) Corrector elements are Corning fused silica ADC elements are Schott LLF1 and N-BK7 Telecentric Chief Ray Normal design to maximize fiber injection efficiency Largest element 1.13-m (current baseline) ADC not critical if fibers can be positioned at interesting lambda per object ADCs LLF1 N-BK7 Focal Surface C4 Fused Silica C3 Fused Silica Ask Peter Doel about details C2 Fused Silica C1 Fused Silica 17

18 Why a large focal plane? BigBOSS 1-m focal plane at f/4.5 Physical space for fibers: 5x larger than DES, 2.8x HyperSuprime Fibers are 120 micron -- smaller == worse Large fiber positioners easier, tolerances easier Focal ratio degradation not as significant at slow f/5 FRD data for BOSS 120 μ fibers at f/5 FRD at f/2.5 Some light degraded by ~0.5 deg Spectrographs designed to accept S.B. * r 2 Some light degraded by ~0.5 deg These photons either lost by internal reflection, or difficult to accept in spectrograph Angle [deg] 18

19 Instrument: Fiber positioners x 5000 R&D at 3 institutions for BigBOSS positioners Challenge to make them small enough (12-mm center-to-center) Reposition time < 60 sec UTSC, China BigBOSS prototypes at 15 mm, 13 mm Berkeley Lab, USA IAA/Granada, Spain David Schlegel

20 BigBOSS instrument: fiber positioners Collaboration with USTC in Hefei, China Experience building 4000 LAMOST fiber positioners 2 rotation axes, 25.4 mm center-to-center spacing Light from one galaxy enters fiber here Challenge is to make these small enough (12mm) Prototype #1: not yet small enough 20

21 Progress of fiber positioner for Bigboss 12mm positioner Prof. Zhai Chao (USTC) 27 21

22 BigBOSS instrument: spectrographs Conceptual design, Eric Prieto (LAM/France) Why 3 arms? Higher throughput because of gratings QSO Lyα channel Å at R~3000 e2v CCDs supernova/qso channel Å at R~3000 LBNL CCDs galaxy channel ,600 Å at R~4200 LBNL Extreme Silicon CCDs 22

23 Instrument: Spectrographs x 10 Instrument designed to be a BAO spectrograph Detect emission-line galaxies at z 1.7 This is why we have high resolution! Otherwise sky much brighter! The trick? At z~1 galaxies are forming stars + strong [O II] emission lines Detect these lines between the airglow Galaxy spectrum z~1 Night sky spectrum David Schlegel

24 Instrument: Spectrographs x 10 Instrument designed to be a BAO spectrograph Detect emission-line galaxies at z 1.7 Observed Spectrum Sky-Subtracted Spectrum λ [OII]λ3726, z=1.4 Resolution > 5000 Split [O II] line Work between sky lines Same as DEEP2 survey David Schlegel

25 Poisson-limit sky-subtraction w/fibers Mathematics developed for correct approach Spectro-Perfectionism - Bolton & Schlegel, astro-ph/ Simulated spectrum Best-fit spectrum PSF Simulated spectrum Best-fit Residuals 1-D resolution function If the 2-D PSF is asymmetric, you cannot have both a symmetric 1-D PSF and independent pixels David Schlegel 25

26 Poisson-limit sky-subtraction w/fibers PSF calibration with NIST tunable laser Collaboration with U. Utah (Adam Bolton) + NIST (Claire Kramer, Keith Lykke) PSF Best-fit Simulated spectrum Residuals David Schlegel 26

27 BigBOSS timeline Apr 2009 White paper Nov 2009 DOE Particle Astrophysics Science Advisory Group (PASAG) BigBOSS is in the early planning stages, but presents a legitimate possibility of achieving a significant fraction of the BAO science goals for JDEM at <$100M cost. Substantial immediate support is recommended for BigBOSS R&D so that ground BAO possibilities are known for timely planning of a coherent ground-space dark energy effort. Nov 2009 NOAO call Large Science Programs Providing New Observing Capabilities for the Mayall 4m Telescope on Kitt Peak Aug 2010 Astro2010 Decadal Survey BigBOSS highly recommended as 1 of 4 Projects Thought Compelling for the Mid-Scale Innovations Program in the cost range $US million. Oct 2010 Telescope proposal submitted Jan 2011 Telescope proposal accepted; begin partnership with NOAO 27

28 BigBOSS timeline Full-sky BAO survey possible by moving instrument south after Kitt Peak 4-m (Northern hemisphere) BigBOSS instrument deployable between sister telescopes Enables massive spectroscopic follow-up for LSST Cerro Tololo 4-m (Southern hemisphere) 28

29 Important decisions/lessons I. Design around BAO requirements (simple!) II. 3 deg diameter FOV allows single exposures on ELGs, double exposures on LRGs, quad exposures on LyAF III. Survey mode could cover 14,000 deg 2 footprint each year IV. R=5000 spectra to see ELGs within sky lines V. Reaching Poisson-limit in sky-subtraction of the data will be critical + computation challenge VI. Full Monte Carlo of the ELGs raw data necessary to understand completeness+contamination Mayall + Blanco telescopes are huge resources A * Ω LSST David Schlegel 29

30 BigBOSS BigBOSS DESpec Square Kilometer Array Conclusions: Mapping dark energy at 0<z<2 feasible + cost-effective for optical surveys Radio surveys not yet proven to compete 30