1. ASIAA NTU PHYS J.H.P.Wu & AMiBA Team To remove the ground pickup and electronic DC component in the data, we tracked the source- (P1) and tail- (P2) patches along the same (Az, El). A differencing (P1-P2) in the analysis successfully extracted out the cluster signal (see below). Platform was also rotated to obtain better u-v coverage (right). The Y.T. Lee Array for Microwave Background Anisotropy (previously known as Array for Microwave Background Anisotropy, AMiBA) is an interferometric experiment designed to study cosmology via the measurement of Cosmic Microwave Background (CMB). It is located at Mauna Loa, Big Island, Hawaii. In 2007, 6 galaxy clusters (z < 0.33) were observed through the Sunyaev-Zel'dovich effect. These are the first science results of AMiBA from which we have studied not only the cluster physics but also the cosmic origin.-= S-Z cluster by AMiBA zRADEC X-ray temp. [keV] β Θc [arcsec] Y2500 (30 GHz) [mJy] Y2500 (145 GHz) [mJy] Hours Integrated AMiBA (86-102 GHz) [mJy] notes A2142 0.08915:58:20.527:13:36.78.68±0.121.0±0.3221.4±8.4--4.57 310 merger; lensing data A2163 0.20216:15:34.1-6:07:26.012.2±1.00.674±0.01087.5±2.51435335.96 330 merger with shock; high-temp. regions A2261 0.22417:22:27.632:07:37.28.82±0.350.516±0.01315.7±1.1404408.22 140 lensing data A2390 0.23221:53:36.817:41:42.810.13±1.100.6752.078-11.22 150 relaxed; lensing data A1689 0.18313:14:39.5-1:20:28.19.66±0.200.609±0.00526.6±0.7574609.38 190 relaxed; almost isothermal ; lensing data A1995 0.32214:52:50.458:02:48.08.59±0.700.770±0.8038.9±5.0254.37 130 AMiBA Spec Dual-channel receiverMMIC; L and RPlatform6 m configurable; carbon fiber Operation frequency86-102 GHzCorrelatoranalog (bandwidth 16 GHz) SiteMauna Loa, Big Island, Hawaii (3400 m in elevation) Mounting systemHexapod ( in polarization; in elevation) 7-element (2006-2008) Antenna60-cm Cassegrain; carbon fiberSynthesized resolution6 arcmin FOV23 arcminObservation typetargeted 13-element (2009-) Antenna120-cm Cassegrain; carbon fiberSynthesized resolution2 arcmin FOV11 arcminObservation typetargeted and survey Based on the S-Z observations in 2007, we have successfully studied the following: 1. Hubble parameter (with X-ray) 2. Baryonic fraction (with lensing) 3. SZ spectrum 4. CMB foreground 5. Detailed methods for calibration and data processing 6. Test of data integrity such as non-Gaussianity test Below is the expected performance in measuring the CMB power spectrum, which is to be observed in 2008. Calibrated with Jupiter, Saturn, and Mars, the figure below shows the constructed images of the observed S-Z clusters. The evident temperature decrement at the centers is a theoretically expected feature for S-Z signals at around 94 GHz (see illustration at the top). These data have been further used to investigate the cluster physics and the origin of the Universe. (The circles indicate the resolution.) Two complementary data subsets were processed separately (see below, left and middle), and their differencing (right) shows no essential residual signal. This provides strong evidence that the observed signal is indeed from a cluster (A2142 in this case) rather than from our instrument. CMB photons S-Z effect CMB photons k ： Boltzmann constant (erg/K) h ： Planck constant T ： CMB temperature y ： Compton-y parameter σ T ： Thomson cross section c ： speed of light m e ： electron mass n e ： electron number density T e ： electron temperature Intensity Frequency (ν) AMiBA (86-102 GHz) SZ effect CMB photons SZ effect: S-Z clusters observed in 2007-= Science goals achieved in 2007 3 Observation Differencing test P1 P2