`
Mark Devlin – University of PennsylvaniaFor the ACT Collaboration
Probing Fundamental Physics Through Measurements of Cosmic Structure
ACT: The Atacama Cosmology Telescope
1
ACT SiteALMA
PolarBearACT
(CLASS)
• 5200 m• Latitude -23o
• 0.5 mm PWV -> 150GHz = 0.02
ACT Site
Generators
15,000 liter Diesel Tank
High bay and Workshop
ABSSupplies
Control and Equipment Room
Telescope
Radio Linkto San Pedro
3
ACT Optics
4
6m
400 kg
1.3 arcmin at 150 GHz
2m
ACTPolOMT TES
Silicon arrays
Feedhorn array
• 3 Optics Tubes• 1 deg FOV• 80 mK DR• 100 µW
1.8 m
30cm
A typical SZE observation with ACT• ACT has 1.3’ resolution at 148 GHz.• ACT images are typically smoothed to 2.4’ for
display purposes (see Hincks et al. 2010).
Hincks et al. 2010
ACT taken by the light of a full Moon(30 second exposure)
6
ACT Results2013• Cosmological parameters from three seasons of data
Sievers et al.• Sunyaev-Zel'dovich Selected Galaxy Clusters at 148 GHz
Hasselfield et al.• The stellar content of galaxy clusters selected using the Sunyaev-Zel'dovich effect
Hilton et al.• Likelihood for small-scale CMB data - Dunkley et al.
2012• Evidence of Galaxy Cluster Motions with the Kinematic Sunyaev-Zel'dovich Effect
Hand et al. - PHYSICS WORLD “Top Ten” Breakthrough for 2012• The Atacama Cosmology Telescope: ACT-CL J0102-4915 "El Gordo,"
a Massive Merging Cluster at Redshift 0.87Menanteau et al. – DISCOVER Magazine #64 Science News 2012
2011• Detection of the Power Spectrum of Cosmic Microwave Background Lensing
Das et al. - PHYSICS TODAY Top Search and Discovery result of 2011
El Gordo
• 11 Sept 2013 – 24 Dec 2013 (500 hrs)• One 150 GHz array installed• Four ~ 70 deg2 patches• Overlap with other surveys for cross-correlation
ACTPol First Season Observations(Naess et al, JCAP(2014))
• One of the 4 ACTPol fields: D6• (Area ~ 60 deg2)
ACTPol First Season Observations(Naess et al, JCAP(2014))
Circa – Just before this meeting(November 2014)
10
• BICEP2• ACTPol hi-res data• Planck data read off plots • POLARBEAR & ACTPol are
direct BB• SPT & “preliminary”
ACTPol are indirect lensing BB
Compilation by L. Page
We detect halo lensing from 12,000 stacked CMASS galaxies at S/N of 3.2 sigma
Best-fit of M200 = 2.0+-1.0 1013 Msolar and C200 = 5.4+-0.8
● Excess seen in all three observing regions
● Signal consistent with Optical Weak Lensing measurement from Miyatakeet. al. 2013
Thermal SZ One-Point PDF at 148 GHzHill et al. (2014) arXiv:1411.8004 — see poster session!
tSZ decrements
148 GHz Tfilt
BinnedHistogram(negative Tfilt only)
• Simple observable: histogram of pixel temperature values• Use info from all clusters in the map, including SNR<5• Optimal one-halo term tSZ statistic: very sensitive to σ8
• Build on earlier ACT tSZ skewness measurement (Wilson++ 2012)
Thermal SZ One-Point PDF at 148 GHzHill et al. (2014) arXiv:1411.8004 — see poster session!
σ8
likelihood
~2x smaller than stat. error from tSZ skewness alone (Wilson++12)
Errors assume 3 seasons of AdvACTPol observations
• Cosmic variance‐limited EE measurement out to ell=2000
• 5x better resolution than Planck with 5x the Plancksensitivity
• 3x more polarization modes than Planck
• New constraints on the CDM cosmology
Advanced ACTPol (AdvACT)
Complete overlap with DES, LSST & DESI survey regions
AdvACT Survey Plans
16
South Pole
ChileD56
BOSS
D7
BICEP2
r=1r=0.01
Planck Foreground Level in Effective r
17
AdvACT Specifications
18
Detector Array Center[GHz]
Width [GHz]
# TES NETCMB[ ]
Map Noisearcmin]
Beamarcmin
Low Frequency (LF) 28 6 80 35 78 7.1
Low Frequency (LF) 41 19 80 32 71 4.8
Medium Frequency (MF) 90 38.5 1760 5.8 7.8 2.2
MF/HF 150 41 2816 5.4 6.9 1.3
High Frequency (HF) 230 100 1056 20 25 0.9
20,000 deg2
Half the sky ‐> r=0.01 at 3‐4 ‐> Subdivide to check isotropy
detector passbands
Advanced ACTPol (AdvACT)
19
• New dichroic polarimeters
• Datta et al., JLTP (2014)
• Array to be deployed on ACT in Jan 2015
Detector wafer
Horn array
Assembled Array
Rotating HWP Provides Stability
• 2Hz rotation ‐> • 8 Hz Modulation ‐>• 800 sec Stability!
Three 30 cm HWPs installed directly in front of the AdvACT receiver
AdvACT Will Test Large‐Field Inflation
Can detect r = 0.01 signal
• Can clean synch and dust• Cleaned maps at both 90
and 150• Can confirm signal is
isotropic and that result is independent of foregrounds
• Measure B mode spectrum
Advanced ACTPol (AdvACT)
22
Projected to improve Planck limit on m
Projected to improve LSST’s DE FOM by 20x!
Big Telescope for Big B‐Modes
23
Antarctica December 2010
BLAST‐Pol 500 μm Inferred B‐Field
Direction in Vela C
Background image: 500 μm polarized intensityContours: 500 μm Total Intensity
4400 Nyquist sampled vectors when smoothed to 2.5 arcmin resolution
Coming Soon – BLAST-TNG
• 2.5 meter Carbon Fiber Mirror• 2200 detectors at 250, 350 and 500 m• 22 arcsec resolution at 250 m• 16 times the speed of BLAST-Pol
• First flight December 2016 with Shared Risk Observing
THE END
28
Top Related