AMiBA 90GHz SZ Observations
Lin, Kai-Yang (林凱揚 ) ASIAA
2013-06-14 K.Y. Lin, CMB2013, Okinawa 1 The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA)
Academia Sinica National Taiwan University With collaborators from ATNF, CMU, JPL, NRAO
Dr. Yuan-Tseh Lee is former President of Academia Sinica and strongly supported the funding and development of AMiBA. He is also the 1986 Nobel laureate in Chemistry (with Dr. Dudley Herschbach) for developing the “crossed molecular beam” method.
2013-06-14 K.Y. Lin, CMB2013, Okinawa 2 AMiBA-13 (2010 - now)
AMiBA-7
(2006 - 2009) 2-element Prototype (2002 - 2004)
2013-06-14 K.Y. Lin, CMB2013, Okinawa 3 AMiBA in one slide …
• Short description – 86-102GHz (3mm), dual polarization (XX, YY) • GaAs HEMT LNA (Trx ~ 65 – 70 K) • Analog lag-correlator with 4 lags (2 spectral channels) • effective bandwidth 11GHz – 3400m above sea level (within Mauna Loa Observatory) – Designed to study CMB and galaxy cluster (via the Sunyaev- Zel’dovich Effect, SZE) in few arcminute scale
• 2006-2009 – 7 element, 0.6m antenna – Primary beam = 23’, Synthesized beam = 6’ – Observed 6 clusters (published 13 papers so far) • 2010- – 13 element, 1.2m antenna – Primary beam = 11.5’, Synthesized beam = 3’ – Observed 24 clusters so far, on-going
2013-06-14 K.Y. Lin, CMB2013, Okinawa 4 Merit of Cluster SZ Sciences
• Integrated total SZ flux (Ysz) or its X-ray proxy Yx=MgasTx is robust against non-gravitational processes – Unlike X-ray luminosity (Lx) or temperature Tx – Good mass proxy with small intrinsic scatter à useful for studying cosmology with cluster mass function • Unresolved SZ signal is a strong component of high-l power in CMB power spectrum (l>3000)
– Can be used to constrain σ8 if we understand gas pressure profile – SPT (Leuker+10) and ACT (Fowler+10) both show deficit high-l power for
WMAP σ8 – Stacked WMAP clusters show weaker SZ signal than model (Komatsh +11) • Planck found SZ-selected clusters have shallower pressure profile than X-ray selected clusters (Planck early results IX, 2011) • Possibly lower SZ signal from stacked Planck data on optically selected cluster candidates (Planck early results XII, 2011)
2013-06-14 K.Y. Lin, CMB2013, Okinawa 5 AMiBA-7 Results
Weak lensing mass map (white contours) on AMiBA-7 SZ iamge The 6 clusters observed by AMiBA-7 (color) for Abell 2142 (z=0.09)
AMiBA-7 (2007-2008)
2013-06-14 Wu et al. 2009 K.Y. Lin, CMB2013, Okinawa Ho et al. 2009 6 Baryon Frac ons in Galaxy Clusters
Distribu on of (hot) baryons with respect to Dark Ma er
AMiBA-7 tSZE + WL + X-ray X-ray and WMAP7 tSZE constraints
Komatsu et al. 10 (WMAP-7yr) 2013-06-14 K.Y. Lin, CMB2013, Okinawa 7 Umetsu et al. 2009 Cluster Scaling Rela ons with Different X-ray Priors
(↓) Y-M rela on ( (↑) AMiBA-7 tSZE-derived cluster parameters Liao et al. 2010 2013-06-14 K.Y. Lin, CMB2013, Okinawa 8 AMiBA-7 expanded to AMiBA-13 2007 2010 - - 2009 now AMiBA7 AMiBA13 Comment Point source 8 mJy/ 4x larger dish 63 mJy/beam sqrt(4)x more correlations sensitivity (1 hr) beam → 8x more sensitive Extended brightness Higher resolution negates the 70 uK 50 uK larger dish size (and more) sensitivity (1 hr) → less than 2x improvement Angular Resolution 6' 2.5' more than 2x longer baselines 2013-06-14 K.Y. Lin, CMB2013, Okinawa 9 Platform Deformation (Liao et al. 2012, submitted) Saddle pattern amplitude and phase change with Az Elevation dependence determined from two optical telescopes 2 2 dz = A1(ε )r cos(2φ + 2α + P1(ε ))+ A2 (ε )r cos(2φ −α + P2 (ε )) (r,φ) = platform plar coordinates (α,ε ) = azimuth, elevation Photogrammetry Results2013-06-14 K.Y. Lin, CMB2013, Okinawa 10 Mass Limit (typical) • Typical integration 100 hr – = 50 hr on-source – ~ 16 hr after flagging + weighting • Model: – gNFW pressure profile (Arnad+10) – C-M relation (Comford & Natarajan 07) 2013-06-14 K.Y. Lin, CMB2013, Okinawa 11 Science Targets • Study cluster gas properties combining AMiBA SZE data with other wavelengths (X-ray, weak-lensing, strong- lensing, SZE at other frequencies and resolutions) • Main sample: – 25 clusters in the CLASH collaboration – 6 clusters with AMiBA-7 measurements – Massive clusters from other X-ray selected samples – Follow-up of high richness cluster candidates from optical surveys (RCS1/2, PS1, HSC, … etc.) • Proceeding at approximately 1.5 clusters per month since June 2011 (down to ~ 6 x 10^14 Msun) 2013-06-14 K.Y. Lin, CMB2013, Okinawa 12 Cluster Images from 2012 2013-06-14 K.Y. Lin, CMB2013, Okinawa 13 AMiBA13 / Bolocam Comparison (II) SZ model converted from 150GHz MACSJ0717 observation by Bolocam/CSO AMiBA-13 Observation (90GHz) • AMiBA flux 25% lower than model. (8σ detection in 13 hour) • 10% loss from band-smearing of delay • Broadly consistent within the error bars. 2013-06-14 K.Y. Lin, CMB2013, Okinawa 14 AMiBA13 / Bolocam Comparison (II) SZ model converted from 150GHz MACSJ0717 observation by Bolocam/CSO AMiBA-13 Observation (90GHz) WL X-Ray (Medeziski+13) • AMiBA flux 25% lower than model. (8σ detection in 13 hour) • 10% loss from band-smearing of delay • Broadly consistent within the error bars. 2013-06-14 K.Y. Lin, CMB2013, Okinawa 15 Combining with AMiBA-7 (figure by Keiichi Umetsu) 2013-06-14 K.Y. Lin, CMB2013, Okinawa 16 What happens next? • mm-level deformation is severe for 3mm obs, but is much less a problem for longer wavelength • A prototype for DACOTA (Dense Array for COsmology and Transient Astrophysics, P-I: Geoff Bower) – Intensity mapping of galaxies coherent on scales of 10s of Mpc through CO(J=1-0) and CO(J=2-1). – 15GHz and 30GHz receivers to map z~7 – Closely related to HI intensity mapping experiments – Not yet funded L • Even if we stay with 90GHz rx, having higher spectral resolution helps remove the continuum band-smearing effect 2013-06-14 K.Y. Lin, CMB2013, Okinawa 17 Digital Correlator Development • Using the CASPER architecture (Collaboration for Radio Astronomy Signal Processing and Electronics Research) • Adopted the packetized correlator design (packetize data and transmit through high-speed network switch) Or by regular Ethernet to every ROACH board 2013-06-14 K.Y. Lin, CMB2013, Okinawa 18 Development • Built 5Gsps ADC (8-bit) board • A one-baseline prototype is tested on site • Next goal is to build a 10Gsps ADC (4-bit) board • Current receiver support RF: 86 – 102 GHz – IF: 2 – 18 GHz • Spectral resolution is configurable (FPGA based) 2013-06-14 K.Y. Lin, CMB2013, Okinawa 19 Prototype Digital Correlator • 8-bit 5Gsps ADC success (next goal is 10Gsps) • Prototype: – Clock only running at 3.2Gsps (1.6GHz bandwidth) / 1024 channels – Single baseline on-site tes ng Bandpass measured with Jupiter HCN and HCO+ (and con nuum) from Orion KL amplitude (linear scale) 2013-06-14 phase K.Y. Lin, CMB2013, Okinawa 20 Summary • Solved the major problem of mm-level deformation. – Band-smearing effect remains and reduces our efficiency ~ 5-10% (depending on obs.) • Probe intermediate scale – Mustang, ALMA will probe ~ 10” – 1’ – Planck probes > 5’ – AMiBA fills with ~ 2.5‘ – 6’ • Targeting a few tens of clusters to study gas content – 6 AMiBA-7 targets: good pressure profile constraint – 24 CLASH targets: combined SL/WL/X-Ray/SZE study – Follow up of other interesting targets: • Optically selected candidates (e.g. RCS2, Pan-STARRS, …) • Rare interacting clusters (e.g. Bullet-like cluster) • Moving on to higher spectral resolution and/or lower frequency 2013-06-14 K.Y. Lin, CMB2013, Okinawa 21 THANK YOU 2013-06-14 K.Y. Lin, CMB2013, Okinawa 22