LSST Cosmology and LSSTxCMB-S4 Synergies. Elisabeth Krause, Stanford

Transcription

1 LSST Cosmology and LSSTxCMB-S4 Synergies Elisabeth Krause, Stanford

2 LSST Dark Energy Science Collaboration Lots of cross-wg discussions and Task Force hacks Junior involvement in talks and discussion Three new milestones! First meeting outside the UK Largest DE School attendance to date First collaboration photo Prepare for, and carry out, cosmology analyses with LSST data Science Working Groups: five key cosmological probes Clusters, Large Scale Structure, Strong Lensing, Supernovae, Weak Lensing Enabling Analyses Working Groups: understand LSST system + systematics Cosmological Simulations, Survey Simulations, Sensor Anomalies, Photometric Calibration, Photometric Redshift Estimation, Computing and Infrastructure

3 1.3 LSST Cosmology Forecasts: SL+SN P(w) Photo-z Spec -z Strong Lensing ~0.5% distances from time delays, 1% on H0 by 2027 Time Delay Cosmography Supernovae Ω Μ -0.2 σ(w0) ~ 0.1, σ(wa) ~ Figure 11.12: Forecasted constraints on a constant equation of state w in a flat cosmolog supernovae. The left panel shows the joint posterior distribution on m and w, assuming an in the distance indicator of 0.12 mag. The green and cyan contours show the 68% and 95% constrai redshifts are used, while the red and after blue contours LSSY showyear1 the same constraints with spectroscopi panel shows the constraints on w marginalized over M. Results are shown separately as spectroscopic redshifts for all supernova hosts, and the more realistic case of photometric red priors were used. w w a 1 2 Treu & Marshall LSST Science Book, Fig w 0

4 LSST DE Equation of State Forecasts w a arxiv: clustering cosmic shear clustern 3x2pt 3x2pt+clusterN+clusterWL w 0 w a Cluster x LSS x WL σ(w0) ~ 0.03, σ(wa) ~ 0.1 transformational improvement from joint analysis conservative budget for included systematics only z < 1 clusters; does not include SL, SN

5 LSST Cosmology Forecasts: LSSxWL Modified Gravity constrain relation between curvature, Newtonian potential =G light /G 1 µ =G matter /G 1 generic parameterization, can be mapped onto MG models work in progress, expect <5% constraints on Σ, optimization for μ ongoing Simpson CFHTLenS LSST LSSxWL preliminary 0.00 Hironao Miyatake (JPL), priv. comm. 0.06

6 Forecasting Details LSSxWL CLxLSSxWL statistics statistics +systematics model

7 LSST Survey Specifications Forecast comparisons require comparable assumptions LSST-DESC working groups converged on LSST-like specifications galaxy, cluster, SN, SL samples redshift distributions, photo-zs key systematics models, model priors default angular, redshift binning Specifications + theory covariances available of DESC wiki How should DESC interface & iterate with CMB-S4 forecasts?

8 LSSTxCMB-S4 Synergies CMB-S4 and LSST are highly complementary in measurements, astrophysics, cosmology uncorrelated obs. systematics different techniques for derived measurements cross-correlate measurements calibrate observational & astrophysical systematics do experiments agree? multi-wavelength studies of clusters, galaxies, feedback joint analysis of consistent measurements maximize constraining power different parameter sensitivities, redshift dependencies [Each example requires specialized forecasts.]

9 LSSTxCMB-S4 Synergies Worked Example Galaxy weak lensing, CMB lensing probe same lensing effect, use different techniques to estimate shear/convergence Use CMB-S4xLSST crosscorrelation to self-calibrate LSST shear bias CMB-S4xLSST validates high-z shear calibration to LSST requirement Shear bias 68% constraints Mean redshift LSST shear: gal gal LSST full: gg, g gal, gal Combi2: gg, g CMB,g gal gal Combi1: CMB CMB, CMB gal, gal gal LSST full & CMB S4 lensing LSST requirement Schaan m 0 m 1 m 2 m 3 m 4 m 5 m 6 m 7 m 8 m 9

10 Summary LSST will image galaxies & transients with excellent accuracy LSST Cosmology constraints depend on systematics mitigation current, incomplete forecasts: σ(w0) ~ 0.03, σ(wa) ~ 0.1 CMB-S4 and LSST highly complementary in measurements, astrophysics, cosmology Complementarity enables systematics calibration through cross-correlations consistency tests optimal cosmology constraints through joint analysis Synergies between forecasting in DESC and CMB-S4?