Transcript clkuo_ACBAR_Linde_mar2008

ACBAR
Chao-Lin Kuo
Stanford Physics/SLAC
CMB power spectrum, as of 03/04/08
mK2
ACBAR – power spectrum final results
On the preprint arxiv: 01/10/08 (astro-ph 08011491)
For this data release, esp.:
Christian Reichardt
(Caltech→Berkeley)
Bill Holzapfel
Chao-Lin Kuo
(Caltech→Stanford)
Andrew Lange
Carlo Contaldi
Dick Bond
Planning/
operation
Cosmological
parameters
Arcminute Cosmology Bolometer Array Receiver (2001-2005)
Cooled to 240mK
He3/He3/He4
Fridge
South pole
corrugated
feed horns
2 meter Telescope
@ South Pole
Bolometers
2 meter mirror
+ 150 GHz =
High resolution (4.8’)
• Map = 11x2.5 deg
sum
•The largest scale structures
(>1 deg) have been filtered
•All structures are real,
larger than the beam size
diff
The CMB damping tail
The damping scale measures the
angular scale of Silk length at recombination:
Silk length ~ 3.5 Mpc (m/ b)1/2 (mh2) -3/4
Dunkley et al, today
Sky Coverage
2001
Year observed: 2002
2005
Kuo, 2004; 16.8 khours ; 63 deg2
Kuo, 2007; 23.0 khours ; 137 deg2
Reichardt 2008; 85.4 khours ; 710
2
ACBAR PS Releases
R08
ACBAR 2004; differenced; 63 deg2; 10.% calibration (Temperature)
ACBAR 2007; undifferenced; 137 deg2; 6.0% calibration
Reichardt 2008; undifferenced ; 710 deg2; 2.3% calibration
Foregrounds
Calibration
(1) Galactic dust
CMB Dipole
FDS
(done by
WMAP)
0.5%
ACBAR favors a lower amplitude: 0.1±0.5
Good news for future polarization exp.
(2) Radio point sources
Estimated residual:
(done by C Reichardt)
ACBAR
2.3%
2.2 (/2600)2 mK2
(3) High-z galaxies
Estimated residual::
9-16 (/2600)2 mK2
Cosmological implications
• The most important result: WMAP-3 model spectrum
is a very good fit (flatness, L, CDM, …) This seriously
limits non standard ingredients.
•Important note:
•Beam uncertainty (published function)
•Calibration uncertainty (2.3% in T)
High-l
CBI/BIMA:
355  103 mK2
at 30 GHz*
ACBAR
34  20 mK2
at 150 GHz
CBI excess is not primordial*
1D
likelihoods
WMAP3
WMAP3+
ACBAR
CMBall
No major surprises.
(Very consistent with
WMAP3 model!)
Adding ACBAR’s
small scale
information shifts c
&  by 1 .
More details:
astro-ph/08011491
Where the constraining power is coming fromThe
3rd
ACBAR
WMAP
BOOM
peak..
500
1000
A. Slosar
1500
2000
2-D parameter contours

ns
Lensing with ACBAR
Lensed
Unlensed
Method 1: Power spectrum:
* ACBAR’s band-power’s are consistent with
a 6-parameter LCDM model.
* Lensed models are favored (~3.1) when
ACBAR is added to WMAP3.
Method 2: Higher order statistics – lens reconstruction
* Generalize Hu’s quadratic estimator for a map with spatial
filters and non-uniform coverage
* ACBAR’s pixel-based maximum likelihood algorithm easy to
generalize for lensing work.
(CK, Dan Babich,..)
* Maximum likelihood analysis by Hirata&Seljak
serves as an important guide line
The Quest for “B”
BICEP & future
QUAD/DASI/SPUD
BICEP
ACBAR
CMB polarization and current measurements
Re-ionization
E
E-mode
B-mode
(lensing)
r = 0.05
B
B-mode
→
(gravity waves)
•
The re-ionization bump (early re-ionization )
•
The E-mode polarization – adiabatic vs
isocurvature modes
•
The lensing B-mode – a probe of the large scale
structure
–
–
–
Dark Energy – equation of state, evolution
Absolute neutrino mass (down to ~0.05 eV)
Geometry
Ongoing @ South Pole: the BICEP Experiment
•Small telescope
•Cold, stable refractive optics
H. Chiang
Bolometric Polarimeters
The state-of-the-art (QUAD, BICEP):
•Co-locating dual-polarization polarimeter
•High optical efficiency, wide band
•Extremely stable
•Nice beam/band
•Low polarization artifacts
•Discrete elements: feeds, filters, detectors
30 cm
BICEP focal plane (98 detectors)
The future:
•To integrate all these components on a Si
wafer → mass production
•Higher packing density
•TES enables SQUID multiplexed read-out
8 cm
Antenna-coupled TES array
(64 detector pairs)
Enabling Technology: lithographic detectors
Al
Load resistor
Ti
Dual-Tc TES bolometer
7.5 mm
(150 GHz)
Dual-polarization
antenna/summing network
25 % Bandwidth Compact LC Filter
0.8 mm
2008
2009-2010