Delensing CMB B-modes: results from SPT. E mode B mode With: K.Story, K.Wu and SPT Alessandro Manzotti (KICP-U. Chicago) arxiv:1612. BCCP talk 25th Oct
not in this talk: LSS and CMB ISW map reconstruction Future surveys forecast LargeScaleStructure effective field theory LSS CosmoSIS: modular parameter estimation Super sample effect S Dodelson W, Hu M. Pietroni Let s talk!!
e-b decomposition, decompose polarized cmb to highlight inflation E mode: produced by scalar anisotropies when CMB photons scatter (recombination and reionization) B mode: produced by tensor (gravity waves) anisotropies when CMB photons scatter (recombination and reionization) B mode: produced by lensing. Turning E mode into B mode Kamionkowski, Kosowsky, Stebbins (1997) Zaldarriaga & Seljak (1997)
T(ˆn) (±350µK) Unlensed E(ˆn) (±25µK) B(ˆn) (±2.5µK) (no primordial B-modes)
T(n ) (±350µK) Lensed E(n ) (±25µK) B(n ) (±2.5µK) (no primordial B-modes)
b-mode lensing spectrum Angular scale P o w e r
delensing is crucial
Crucial In 10 years (CMB Stage 4) it could be the main source of noise for primordial B mode signal. It can be seen as a white noise component at ~5 uk-arcmin. Not cleanable with multi frequencies. Well modeled, but cosmic variance would be a problem Abazajian, K.N. et al.
no surprise: it will limit inflationary constraints and more Our constraint on the inflationary tensor perturbation and tilt will depend on it It will limit lensing reconstruction (a.k.a as iterative delensing) Sherwin Schmittfull. It will limit parameter that depends on peak position and damping tail information like N_eff Simard
and more Green, Meyers, van Engelen
what can we do? build a template and remove! B-mode data B-mode template 23 h 0 h ˆB lens ( - DEC (J2000) 51 54 ) 2 57 60 ±1.5µK RA (J2000)
TEMPLATE: what modes do we need? = Integral of structures along the line of sigh B-mode multiple you want to delens Mainly from large scale potential l>100 E_mode from scales slightly smaller than B_lens Simard,Hanson,Holder 2014
How can we get those modes? Your favorite CMB experiment We want Kernel overlap Low Noise CIB CMB Galaxies Cosmic Infrared Background The best method right now. Already used on data by SPT (Hanson B-modes paper). CIB model uncertainties not limiting now, you can marginalize over it (Sherwin Schmittfull.) In the future it will be the best source of phi reconstruction. Not there yet but already powerful if combined with the CIB Low redshift. They do not probe well the sources that lens the CMB. Maybe useful to check for systematics. SKA?
optimal source for a lensing map? Where the lenses are How much are they correlated with lensing considering noise Redshift Angular Scale
delensing is crucial, feasible but hard.
However a new phase is beginning: we are now delensing
a (quite local) success in temperature Real space CIB delensing of Planck TT data. Patricia Larsen, Anthony Challinor, Blake D. Sherwin, Daisy Mak
the south pole telescope story, delensing the B-modes
the spt story, the data CIB map, from Herschel 500μm map. 23 h 0 h Internal CMB slightly worse ˆCIB 51 Dec (J2000) 54 57 60 ±3 10 6 RA (J2000) E mode (Crites, SPT 2015) B mode (Keisler, SPT 2015)
B template: the pipeline Construct a lensing template from the CIB map ˆ = C CIB CIB CIB ` (C` C` ) 1 T` CIB Filter the E-mode map with a C-inv Wiener filter: `xmin `max Build a B template Make it as similar as possible to the data. Apply Transfer function B lens Note: This is a signal to noise filtered template
Bb power: the pipeline Convolutional clean each bundles. Split map into bundles. Cross spectrum-pseudo Cl Apply Wiener filter Remove additional and multiplicative bias C BB `
putting them together : delensing pipeline E mode Cinv filter CIB Phi Template B-template Apply transfer function Note: The subtraction happen in Fourier space Bundled Bmode Cleaning TE Delens Cross Spectrum power B res (`) =B lens (`) ˆBlens (`)
DATA
spt 15-20% delensing: the maps 23h 0h ˆCIB Dec (J2000) 51 23h 0h B lens 54 51 60 ±3 10 6 RA (J2000) 23h 0h 150 E proj DEC (J2000) 57 54 57 DEC (J2000) 51 54 60 RA (J2000) 57 60 ±1.5µK ±15µK RA (J2000)
Work 2 years on simulations, filtering
spt 15-20% delensing: the band powers 1.2 1.0 Combined `C BB [10 3 µk 2 ] ` 0.8 0.6 0.4 0.2 0.0 0.2 Old Analysis 0.4 0 500 1000 1500 2000 2500 `
spt 15-20% delensing: the band powers 1.2 1.0 Combined `C BB [10 3 µk 2 ] ` 0.8 0.6 0.4 0.2 0.0 0.2 Delens 0.4 0 500 1000 1500 2000 2500 ` slides at:
spt 15-20% delensing: the band powers 1.2 Original Bandpowers 1.0 0.8 Combined A lens =1.34 ± 0.31 A delens =1.02 ± 0.30 `C BB [10 3 µk 2 ] ` 0.6 0.4 0.2 0.0 Delensed Bandpowers P 1.0 0.8 0.6 0.4 Lensed Delensed 0.2 0.4 0.2 0 500 1000 1500 2000 2500 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 A BBlens ` slides at:
spt 10% delensing: the systematic tests Run and passed so far Low-ell cut in E mode: important push as low as possible High-ell cut in E mode CIB model assumed Curl Estimator Noise only maps slides at:
And the future will be even brighter, delensing will improve slides at:
SIMS Note: we have filtering, foregrounds (gaussian), CIB from model. slides at:
delensing: long (exciting) way to go. This analysis slides at:
delensing efficiency: big picture B template power spectrum 10 3 C template 10 4 better iterative? 10 3 ` ` E unfiltered noiseless E noisy CIB E noiseless BB Theory noiseless E unfiltered E noisy CIB noiseless slides at:
delensing efficiency: big picture Lensing Clbb residuals 1.0 } CIB 0.8 C delensed /C B 0.6 0.4 } true 0.2 } Ē true true iterative? 0.0 500 1000 1500 2000 ` better (less residual power) E unfiltered E noiseless BB Theory noiseless noiseless E noisy E unfiltered E noisy CIB CIB noiseless slides at:
C delensed /C B 1.0 0.8 0.6 0.4 } } delensing efficiency: maps 0.2 }Ētrue true 0.0 500 1000 1500 2000 ` iterative? slides at:
1.0 C /C 0.8 0.6 0.4 0.2 0.0 iter 500 1000 1500 2000 ` } Ētrue true delensing efficiency: Perfect input iterative? slides at:
1.0 C /C 0.8 0.6 0.4 delensing efficiency: noiseless filtered E } true 0.2 0.0 iter 500 1000 1500 2000 ` slides at:
1.0 C /C 0.8 0.6 0.4 } true delensing efficiency: noisy filtered e 0.2 0.0 500 1000 1500 2000 ` At least for SPT at this scales. E modes are not the problem slides at:
1.0 0.8 } CIB C delensed /C B 0.6 0.4 delensing efficiency: maps 0.2 0.0 500 1000 1500 2000 ` iter Indeed perfect E but lensing from CIB.. Better
1.0 0.8 } CIB C delensed /C B 0.6 0.4 delensing efficiency: maps 0.2 0.0 500 1000 1500 2000 ` slides at:
the challenges The B mode map and the B mode template we want to subtract are coming from different analysis. They have different filtering, missing modes, different point sources threshold. We are testing the technique for the first time on data. Using this to improve r constraint required an unprecedented control of systematics. Analyze delensed data. Covariances? Estimate systematics contamination: dust. slides at:
the future Reasonable goals by end of 2017 Lensing Potential from CIB v.s. CMB reconstruction On the 500deg^2 SPT combine Planck CIB and CMB lensing reconstruction. CMB S4 SPT 3G Now 23 h 0 h ˆCIB 51 Dec (J2000) 54 57 60 ±3 10 6 RA (J2000) Delens BICEP-KECK with the help of BICEP data. Sherwin & Schmittfull 2015 slides at:
advertisement: 2dx3d formalism in galaxy surveys With Sam Passaglia 1st year We know how to get cosmology from 2D samples Expand in Ylm(θ) Compute almal m For 3D, we usually expand in eikx... but if we want to cross-correlate with 2D: Expand in Ylm(θ) AND jl(kr) Compute almbl m (k) and blm(k)bl m (k ) Retains diagonality in l and m
Application: Photo-z Galaxies and Clusters Photometric surveys produce tomographic galaxy bins Each bin essentially a 2D sample We can use our framework to make optimal use of overlapping 3D samples Ex: redmapper Clusters, Spectroscopic galaxies For DES clustering analyses, clusters are lumped with galaxies What if we treat clusters as a true 3D sample?
Results: Fisher Analysis for a DES-like survey 0.3 1 error ellipse for 8 and b 1 error ellipse for z 0 and phot 0.2 0.12 0.11 0.1 b phot 0.10 0.0 0.09 0.1 0.08 0.2 1.0 0.5 0.0 0.5 1.0 1.5 2.0 2.5 8 0.40 0.45 0.50 0.55 0.60 z 0
conclusion Delensing is crucial and it is working. Results in agreement with sims. Right now all the collaborations and the CMB Stage 4 community are working hard. Happy to chat about: - 2Dx3D formalism - dark matter perturbation theory - LIGO early localization of electromagnetic counterparts, - modular software for parameters constraints, - CMB Stage 4 and galaxies forecast, - optimal map reconstruction: ISW - effect of long wave modes on deep CMB experiments. Alessandro Manzotti, KICP Chicago slides at: