High Resolution Observations of the CMB with the CBI Interferometer
XVIIIth IAP Colloquium - July 1 2002
Carlo Contaldi
CITA
T. Readhead (Caltech)
T. Pearson (Caltech)
S. Myers (NRAO)
B. Mason (Caltech/NRAO)
J. Sievers (Caltech)
J. Cartwright (Caltech)
P. Udompraesert (Caltech)
M. Shepherd (Caltech)
A. Farmer (Caltech)
S. Padin (Caltech)
J. R. Bond (CITA)
C. Contaldi (CITA)
D. Pogosyan (U of Alberta)
U.-L. Pen (CITA)
M. Ruetalo (CITA/UofT)
P. Zhang (CITA/UofT)
J. Wadsley (McMaster)
S. Prunet (IAP)
•13 elements
•0.90 m dishes
•45’ FWHM
•78 baselines
•10 frequency channels 26-36 GHz
l~200
The Cosmic Background Imager
> 5000m Atacama Plateau Chile
10-channel single pointing uv-coverage 26-36 GHz
single pointing uv-coverage
mosaic pointings
CBI Power spectrum extraction
•Visibilities ‘gridded’ in uv plane [Myers at al. 2002].
•Quadratic estimator solves for the ML band powers
•6x7 field mosaic; ~10 hrs. 16 processor GS320 cluster @ CITA
•Foreground templates projected out using known positions
Sj = QijVi Cij = hSiS?j i
CB =P
` `W`
BC̀
C Tot = C N+C CMB+C src+C res
CBI Mosaic Power Spectrum
•3 6x7 field mosaics
•~ 145’x165’ each
•~ 40 sq. deg.
[Pearson et al. 2002]
“Silk” damping
eà (`=̀D)mD
Mosaic Window Functions
! c ! b ÒË Òtot ns üc
Weak
Weak + Flat +LSS
Flat + LSS + HST-h
0:17+0:08à0:06 0:022+0:015à0:009 0:40+0:25à0:27 0:99+0:12à0:12 1:05+0:09à0:08 0:24+0:18à0:17
0:13+0:02à0:01 0:025+0:010à0:008 0:64+0:10à0:13 1:01+0:10à0:07 0:15+0:17à0:11
0:13+0:02à0:01 0:027+0:009à0:008 0:68+0:05à0:07 1:04+0:08à0:07 0:19+0:15à0:13
CBI+DMR[Sievers et al. 2002]
CBI Deep Field
Power Spectrum
BOOMERanG2001
[Mason et al. 2002]
CBI High-l Excess
Significant power above l=2000. 3.5 inconsistent with zero and 3.1 inconsistent with best-fit model.
Secondary Anisotropies from Sunyaev-Zeldovich Effect?
Amplitude ~ 4.5 higher than expected signal from residual low-flux sources
Estimate includes 50% error in residual source flux.
Raw map
Total Signal
CMB + ?
OVRO & NVSS Source residuals
SZE Angular Power Spectrum
•Smooth Particle Hydrodynamics (5123) [Wadsley et al. 2002]
•Moving Mesh Hydrodynamics (5123) [Pen 1998]
•143 Mpc 8=1.0
•200 Mpc 8=1.0
•200 Mpc 8=0.9
•400 Mpc 8=0.9
[Bond et al. 2002]
Dawson et al. 2002
Simulation of Deep Observations by the CBI
Input SZ map Reconstructed Signal
Bandpower Estimation with a SZ Foreground
CBI Pipeline recovers input SZE signal at observed amplitudes
Non-Gaussian scatter from the SZ signal is significant in the high-l band given the small areas observed
Single Deep Field (08h) simulated observation
Flat
HST-h
Priors
LSS parameters from CMB and other
Cosmological Surveys
•The CBI observations l<2000 give consistent parameters with those of previous experiments on larger angular scales
•Measurement of the damping tail at l>1000
•6’ scales probing ~1014MO seeds of clusters
•High-l excess; Simulations show the Sunyaev-Zeldovich Effect fits the observed power for 8~1.0. This is in the high-end of the range allowed by CMB and LSS surveys
•SZE: high-accuracy determination of 8. Break 8-ΩM degeneracy ΩΛ
•Follow-up on excess
•Extended mosaic data ~ 80 sq. deg.
•Improved hydrodynamical simulations
Summary
•Optimally configured for resolution of peaks
•Polarization upgrade nearly complete
•Calibration runs in August
Polarization Observations
2002/3