1. Precision Studies of Dark Energy with the Large Synoptic Survey Telescope David L. Burke SLAC for the LSST Collaboration Rencontres de Moriond Contents and Structures of the Universe

2. The LSST Collaboration Brookhaven National Laboratory Harvard-Smithsonian Center for Astrophysics Johns Hopkins University Las Cumbres Observatory Lawrence Livermore National Laboratory National Optical Astronomy Observatory Ohio State University Pennsylvania State University Research Corporation Stanford Linear Accelerator Center Stanford University University of Arizona University of California, Davis University of Illinois University of Pennsylvania University of Washington

3. Outline The LSST Mission The LSST Telescope and Camera Dark Energy Science Schedule and Plans

4. The LSST Mission Photometric survey of half the sky (  20,000 square degrees). Multi-epoch data set with return to each point on the sky approximately every 3 nights for up to 10 years. Prompt alerts (within 60 seconds of detection) of transients to observing community. Fully open source and data. Deliverables Archive 3 billion galaxies with photometric redshifts to z = 3. Detect 250,000 Type 1a supernovae per year (with photo-z < 1).

5. LSST Performance Specifications Cadence of two 15 second exposures with 2 second read-out followed by 5 second slew (open-loop active optics) to new (nearby) pointing. FOV = 3.5 degrees diameter. Single-exposure Depth = 24.5 AB mag. (r-band) Stacked (300-400 exposures) Depth = 27.8 AB mag. (r-band) Median Image PSF (FWHM) = 0.7 arc-sec. Broad-band (ugrizy; 350nm-1050nm) internal photometric accuracy of 0.010 mag (zero-point across the sky). Relative astrometric accuracy of 10 mas.  Fast, Wide, Deep, and Precise

6. Telescope and Camera 8.4m Primary-Tertiary Monolithic Mirror 3.5° Photometric Camera 3.4m Secondary Meniscus Mirror

7. Telescope Optics PSF controlled over full FOV. Paul-Baker Three-Mirror Optics 8.4 meter primary aperture. 3.5° FOV with f/1.23 beam and 0.20” plate scale.

8. Similar Optical Mirrors and Systems Large Binocular Telescope f/1.1 optics with two 8.4m primary mirrors. SOAR 4.2m meniscus primary mirror

9. Camera Filters and Shutter Refractive Optics Focal Plane Array (at 153 K) Cryostat ~ 2m

10. Focal Plane Array (FPA) Shack-Hartmann Wavefront Sensors and Fast Guide Sensors 3.5° Field of View (634 mm diameter) Pixels: 3.2  10 9 on 10  m pitch. Plate Scale: 0.200 arc-sec. FPA Flatness: 10  m peak-valley. “Raft” of nine 4k  4k CCDs

11. Survey Power

12. Multi-Epoch Data Archive Average down instrumental and atmospheric statistical variations. Large dataset allows systematic errors to be addressed by subdivision.

13. Multi-Epoch Data Archive Average down instrumental and atmospheric statistical variations. Large dataset allows systematic errors to be addressed by subdivision.

14. LSST Dark Energy Highlights o Weak lensing of galaxies to z = 3. Two and three-point shear correlations in linear and non-linear gravitational regimes. o Supernovae to z = 1. Discovery of lensed supernovae and measurement of time delays. o Galaxies and cluster number densities as function of z. Power spectra on very large scales k ~ 10 -3 h Mpc -1. o Baryon acoustic oscillations. Power spectra on scales k ~ 10 -1 h Mpc -1.

15. Disclosure and Agreement Unless stated otherwise, error forecasts are not marginalized over unspecified parameters. Generally, flat-space ΛCDM values are assumed for unspecified parameters. Do you accept the terms and conditions of this agreement? I accept. I do not accept. 

16. D LS DSDS  = 4GM/bc 2 Impact Parameter b   4GM/bc 2 Sheared Image Shear Gravity & Cosmology change the growth rate of mass structure. Cosmology changes geometric distance factors. D LS DSDS Weak Lensing Geometry

17. Shear Power Spectra Tomography  LSST expects well below 0.001 in residual shear error …. 0.01 0.001 Needed Shear Sensitivity Linear regime Non-linear regime ΛCDM Measure Shear spatial auto-correlation binned in z. Cross correlations between different bins in z. Differing sensitivities to cosmology and gravity.

18. <shear> = 0.07 = 0.07 = 0.000013 RawDe-trailedPSF Corrected 13 arcmin (l = 40) = 0.04 = 0.000007 Single 10 sec exposure in 0.65 arcsec seeing. Weak Lensing Through the Atmosphere Data from Prime-Cam on 8-m Subaru LSST Goal: Residual shear  0.0001. Train on random half of the stars; measure residual shear on other half.

19. Residual 2-Point Shear Correlations  CDM shear signal Typical separation of reference stars in LSST exposures. LSST multi-epoch survey provides sensitivity well below target signal.

20. Photometric Redshifts and Weak Lensing Contours of constant error in w and w a as functions of statistical and systematic photo-z errors. Ma, Hu, Huterer (2005) Need to know bias and resolution in z with good accuracy. LSST goal …  z bias  0.002  (1 + z)   Z  0.003  (1 + z) … will match systematic errors in cosmological parameters to statistical errors for z  3. 

21. Photo-z Calibration Campaign Together with angular correlations of galaxies, this training set enables LSST 6-band photo-z error calibration to better than required for LSST statistics limit precision cosmology Transfer fields - 200,000 galaxies with 12-band photo-z redshifts. Calibrate 12-band photo-z with subset of 20,000 spectroscopic redshifts. Simulation of 6-band photo-z distribution for LSST dataset. Simulation of 12-band photo-z calibration field at 26 AB mag. Need to calibrate transfer photo-z to 10% accuracy to reach desired precision  z  0.05 (1+z)  z  0.03 (1+z)

22. Simulated light curves from the LSST deep field survey. Simulated Hubble diagram from 30,000 supernovae detected over three years of observing in the LSST deep-field survey. Studies of Supernovae with LSST LSST Supernovae Data Sets Survey cadence will detect 250,000 supernovae per year (to z  0.8), and provide photometry every three days in rotating colors (primarily r, i, and z). Nightly deep-field survey will detect and follow supernovae to z  1.2. z = 0.8 photo-z

23. Weak Lensing and SNe-Ia Forecasts Combined JDEM SNe LSST WL Principal component analysis [Huterer and Starkman (2003)] of expected sensitivity to dark energy equation of state. Combination of distance measurements from SNe with parameters from weak lensing …. Complementary probes of cosmology and gravity. w w a

24. R S ~140 Mpc Standard Ruler Two Dimensions on the Sky Angular Diameter Distances Three Dimensions in Space-Time Hubble Parameter Baryon Acoustic Oscillations (BAO) CMBBAO Baryon-DM Gravitational Effects Mode Coupling Clustering In-Fall Velocity Dispersion along Line-of-Sight

25. BAO Power Spectra Two-dimensions on the sky. 3 billion galaxies. Combination yields accuracy 2 % on w 0. < ~

26. Three-Dimensional BAO and Hubble Suppression of line-of-sight modes by photo-z errors. P photo-z (k,μ) = P z (k,μ)  Present error on H. Accuracy needed for LSST WL and SNe. May do better. We will see.

27. LSST Project Milestones and Schedule 2006 Site Selection Construction Proposals (NSF and DOE). 2007-2008 Complete Engineering and Design Long-Lead Procurements 2009-2012Construction and First Light 2013Commissioning

28. LSST Site Selection – Two Proposals Final Selection – 14 April 2006 San Pedro Mártir Cerro Pachón

29. Summary The LSST will be a significant step in survey capability. Optical throughput ~ 100 times that of any existing facility. The LSST is designed to control systematic errors. We know how to make precise observations from the ground. We know how to accurately calibrate photo-z measurements. Multi-epoch with rapid return to each field on the sky – advantages likely not yet fully appreciated. The LSST will enable multiple simultaneous studies of dark energy. Complementary measurements to address degeneracy and theoretical uncertainty in a single survey. The LSST technology is ready.