LSST + BigBOSS 3.5 deg 3 deg Natalie Roe LSST Dark Energy Science Collaboration Workshop U. Penn, June 12, 2012
Outline BigBOSS Overview BigBOSS-N Science Goals BigBOSS-S + LSST Summary 3.5 deg 3 deg Natalie Roe LSST Dark Energy Science Collaboration Workshop U. Penn, June 12, 2012
BigBOSS Overview KPNO Mayall Telescope 3 FOV corrector Ten 3-arm spectrographs Focal plane 35m Fiber run CCD Image with spectra 5000 Fiber positioners
BigBOSS Collaboration US Groups: Brookhaven National Laboratory Fermi National Accelerator Laboratory Johns Hopkins University Lawrence Berkeley National Laboratory National Optical Astronomy Observatory New York University The Ohio State University SLAC National Accelerator Laboratory University of California, Berkeley University of California, Santa Cruz/Lick Observatory University of Kansas, University of Michigan University of Pittsburgh, University of Utah Yale University, Carnegie Mellon Univ 4 US Nat l Labs 11 US Universities France, Spain, UK Korea, China International Groups: French Participation Group: APC, IAP- Paris; CPP, CPT, LAP Marseille; CEA, IRFU Saclay Spanish Participation Group: IAA, Granada; IAC, Tenerife; ICC, Barcelona; IFT, Madrid; U. Valencia UK Participation Group: Durham, Edinburgh, UC London, Portsmouth Shanghai Astronomical Observatory IEU / Ewha Womans University, Korea University of Science and Technology of China
BigBOSS Status BigBOSS first described in a 2009 white paper Reviewed in 2009 by HEPAP/PASAG Substantial immediate support for BigBOSS R&D is recommended Reviewed by Astro2010 (decadal survey) One of three compelling mid-scale projects in HEP (+HAWC, CMB) BigBOSS proposal submitted October 2010 to NOAO Large Science Programs call (following DES model) Reviewed by Schmidt committee and accepted by NOAO; awarded 500 nights on Mayall Telescope Successful review by DOE in December 2011 state-of-the art in BAO measurements competitive with the BAO components of proposed space-based stage IV missions. BigBOSS is currently in a funded R&D phase. Requested a 2014 construction start; on sky by end of 2017 Possible move to CTIO in 2022 after completion of 5-year survey 5
BigBOSS Science Goals The Stage IV dark energy experiment for BAO and RSD 14,000 sq degree northern hemisphere survey 10X larger than SDSS + SDSS-II + BOSS 2.5 million QSOs 18 million ELGs 4 million LRGs 6 6
BigBOSS Science Goals BOSS will complete BAO+RSD stage III in 2014 1.5 million galaxies + 160,000 QSOs 1% measure of expansion at z ~ 0.3 and 0.5 (LRGs) 2% measure at z=2.5 (Ly-alpha forest) BigBOSS is the Stage IV BAO + RSD experiment 20 million galaxies + 2.5 million QSOs BAO: Geometry, sub-percent precision from z=0.5 1.6 and z=2 3 RSD: Gravitational growth, 2% precision @ 5 redshifts Sum of Neutrino masses to 0.024 ev rms Inflation probe using more modes than Planck BigBOSS science is complementary to LSST science; potential for great synergy if combined 7
V /V BigBOSS Sub-percent precision on standard ruler, plus separation into transverse (distance d A ) and radial (H(z)) modes.
z BigBOSS 1-2% precision on growth rate. Important for distinguishing models, testing gravity.
BigBOSS-N survey from Kitt Peak Redshift map covering ~4000 deg2 of LSST BigBOSS proposal, Section 6
1 BigBOSS-N => BigBOSS-S Full-sky survey possible by moving instrument south after 2017-2022 Synergy with LSST imaging survey Kitt Peak 4-m (Northern hemisphere) BigBOSS instrument deployable between sister telescopes (cf NEWFIRM instrument) Cerro Tololo 4-m (Southern hemisphere)
BigBOSS-S from CTIO Redshift map covering remainder of LSST footprint Could begin ~2022 (requires 1st year LSST imaging for South targets) LSST Science Book, Chap. 2
Advantages of LSST + BigBOSS SDSS has shown that imaging + spectroscopy is far more powerful than either alone BigBOSS-N provides ~7M redshifts in LSST footprint BigBOSS-S could provide full overlap for LSST footprint More accessible to US community for broad survey program than either PFS/Subaru or JWST Spectrograph line-sensitivity is 5x10-17 ergs/cm 2 /sec into a R~4000 resolution element in a 15 minute exposure (S/N~5). Can work at the continuum, eg. all night exposures to R AB =23.5mag per Angstrom (S/N=1) DES-BigBOSS Joint Working Group has already explored some potential imaging/spectroscopic synergy
LSST+BigBOSS Supernova Survey BigBOSS proposal, bigboss.lbl.gov section 3.7 300 square degrees... with host magnitudes reaching r~23-24... to obtain redshifts of all 300,000 LSST SN Ia, requiring ~60 nights total. This is well within the range of past NOAO survey programs.
LSST+BigBOSS Supernova Survey BigBOSS proposal, bigboss.lbl.gov section 3.7 Proof of concept with AAOmega 392-fibers on AAT 4-m Follow-up of SNLS SN host galaxies to z~1 in 3-15 hr exposures Worse site+seeing, lower throughput than BigBOSS
LSST+BigBOSS Supernova Survey Proof of concept with AAOmega 392-fibers on AAT 4-m Follow-up of SNLS SN host galaxies to z~1 in 3-15 hr exposures Worse site+seeing, lower throughput than BigBOSS The AAT 4-m with 392 fibers was more efficient than comparable time on the VLT 8-m with FORS1 and FORS2
DES-BigBOSS JWG Report James Annis, Gary Bernstein, Patrick McDonald, Jeffrey Newman, Nikhil Padmanabhan, Will Percival, David Weinberg Considered 500-3000 sq deg overlap for DES WL + BigBOSS RSD, and cross-correlation calibration technique to improve DES photo-z s Found that galaxy bias determination from DES WL did not significantly improve growth constraints from BigBOSS RSD the internal calibration of bias parameters from BigBOSS RSD is already so powerful that the WL calibration cannot improve it much gains are largest when the imaging and spectroscopic data sets are effectively matched in depth Improvement in BigBOSS galaxy bias parameters through overlap with DES WL map Solid = 3000 sq deg overlap Dashed = no overlap Upper curve, kmax=0.05 h/mpc Lower curve, kmax=0.10 h/mpc LRG ELG
DES-BigBOSS JWG Report James Annis, Gary Bernstein, Patrick McDonald, Jeffrey Newman, Nikhil Padmanabhan, Will Percival, David Weinberg Improvement to DES WL growth constraint using cross-correlation calibration technique (Newman et al) was significant Compared cross-correlation to conventional calibration assuming complete training set of 100,000 redshifts to full DES depth with 0 and 5% redshift failures DES WL improvement equivalent to 44-78% increase in DES area solid=cross correlation for 500 and 3000 sq deg overlap dash = 100,000 spectro training set for 0 and 5% redshift failure rates error on <z> vs z error on σ z vs z
DES-BigBOSS JWG Report James Annis, Gary Bernstein, Patrick McDonald, Jeffrey Newman, Nikhil Padmanabhan, Will Percival, David Weinberg Other potential benefits for systematic studies and other science cases identified but not quantified; taken together, at least as important as prior considerations velocity dispersions as a cluster mass indicator, assessment of intrinsic alignment contrib to WL signals, galaxy-galaxy lensing measurements of the halo profiles and environments of BigBOSS galaxies, detailed constraints on the non-linear bias between galaxies and dark matter improved measurements of the evolution and clustering of quasars and AGN It would seem natural to extend this analysis to quantify the benefits of LSST-BigBOSS overlap, considering both BigBOSS-N and BigBOSS-S
Summary: BigBOSS + LSST LSST will be the centerpiece of the US Dark Energy Program in the next decade with world-leading DE program in weak lensing, SNe and galaxy clusters BigBOSS is a complementary program that could also leverage the LSST investment in the future a world-leading experiment in BAO and RSD with a 2017-2022 northern survey from the Mayall that provides a bridge between DES and LSST extend to full sky with BigBOSS-S and provide dedicated, wide-field multi-object spectroscopy for LSST follow-up and calibration from the Blanco starting in 2022 Further study of the quantitative benefits of BigBOSS- LSST overlap may be warranted