B. Westbrook
A5008108917- Radio Astronomy Observations and Technology
- Superconducting and THz Device Technology
- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Particle Detector Development and Performance
- Adaptive optics and wavefront sensing
- Astrophysics and Star Formation Studies
- Spacecraft Design and Technology
- Dark Matter and Cosmic Phenomena
- Precipitation Measurement and Analysis
- Spacecraft and Cryogenic Technologies
- Microwave Engineering and Waveguides
- Computational Physics and Python Applications
- Antenna Design and Optimization
- Thermal Radiation and Cooling Technologies
- Soil Moisture and Remote Sensing
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Particle physics theoretical and experimental studies
- Physics of Superconductivity and Magnetism
- Gamma-ray bursts and supernovae
- Radio, Podcasts, and Digital Media
University of California, Berkeley
2014-2024
Lawrence Berkeley National Laboratory
2009-2016
Cardiff University
2009-2016
University of Colorado Boulder
2009
National Institute of Standards and Technology
2009
McGill University
2009
Laboratory for Atmospheric and Space Physics
2009
We present a measurement of the $B$-mode polarization power spectrum cosmic microwave background (CMB) using taken from July 2014 to December 2016 with POLARBEAR experiment. The CMB spectra are measured observations at 150 GHz an instantaneous array sensitivity $\mathrm{NET}_\mathrm{array}=23\, \mu \mathrm{K} \sqrt{\mathrm{s}}$ on 670 square degree patch sky centered (RA, Dec)=($+0^\mathrm{h}12^\mathrm{m}0^\mathrm{s},-59^\circ18^\prime$). A continuously rotating half-wave plate is used...
<i>Aims. <i/>We aim to demonstrate the usability of mm-wavelength imaging data obtained from APEX-SZ bolometer array derive radial temperature profile hot intra-cluster gas out radius <i>r<i/><sub>500<sub/> and beyond. The goal is study physical properties by using a non-parametric de-projection method that is, aside assumption spherical symmetry, free modeling bias.<i>Methods. use publicly available X-ray spectroscopic-imaging in 0.7-2 keV energy band <i>XMM-Newton<i/> observatory our...
The Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument is a millimeter-wave cryogenic receiver designed to observe galaxy clusters via the effect from 12 m APEX telescope on plateau in Chile. contains focal plane of 280 superconducting transition-edge sensor (TES) bolometers instrumented with frequency-domain multiplexed readout system. are cooled mK three-stage helium sorption refrigerator and mechanical pulse-tube cooler. Three warm mirrors, two 4 K lenses, horn array...
The Simons Array is a next generation cosmic microwave background (CMB) polarization experiment whose science target precision measurement of the B-mode pattern produced both by inflation and gravitational lensing. As continuation extension successful POLARBEAR experimental program, will consist three cryogenic receivers each featuring multichroic bolometer arrays mounted onto separate 3.5m telescopes. first these, also called POLARBEAR-2A, be to deploy in late 2016 has large diameter focal...
We present the first measurement of cross-correlation between lensing potential, reconstructed from cosmic microwave background (CMB) polarization data, and shear field galaxy shapes. This is made using data Polarbear CMB experiment Subaru Hyper Suprime-Cam (HSC) survey. By analyzing an 11 deg2 overlapping region, we reject null hypothesis at 3.5σ constrain amplitude cross-spectrum to , where normalized with respect Planck 2018 prediction, based on flat Λ cold dark matter cosmology. The this...
ABSTRACT The use of galaxy clusters as precision cosmological probes relies on an accurate determination their masses. However, inferring the relationship between cluster mass and observables from direct observations is difficult prone to sample selection biases. In this work, we weak lensing best possible proxy for calibrate Sunyaev–Zel’dovich (SZ) effect measurements APEX-SZ experiment. For a well-defined (ROSAT) X-ray complete sample, integrated Comptonization parameter, YSZ, weak-lensing...
We present measurements of the angular power spectrum millimeter wave anisotropies with APEX-SZ instrument. has mapped 0.8 deg2 sky at a frequency 150 GHz an resolution 1'. These new significantly improve constraints on anisotropy over range multipoles 3000 < ℓ 10, 000, limiting total astronomical signal in flat band to be less than 105 μK2 95% CL. expect both submillimeter-bright, dusty galaxies and lesser extent secondary cosmic microwave background from Sunyaev–Zel'dovich effect (SZE)...
EBEX is a balloon-borne telescope designed to measure the polarization of cosmic microwave background radiation. During its eleven day science flight in Austral Summer 2012, it operated 955 spider-web transition edge sensor (TES) bolometers separated into bands at 150, 250 and 410 GHz. This first time that an array TES has been used on balloon platform conduct observations. Polarization sensitivity was provided by wire grid continuously rotating half-wave plate. The implementation bolometer...
We present thermal Sunyaev–Zel'dovich effect (SZE) measurements for 42 galaxy clusters observed at 150 GHz with the APEX-SZ experiment. For each cluster, we model pressure profile and calculate integrated Comptonization Y to estimate total energy of intracluster medium (ICM). compare measured values X-ray observables ICM from literature (cluster gas mass Mgas, temperature TX, YX = MgasTX) that relate cluster mass. measure power-law scaling relations, including an intrinsic scatter, between...
We describe the Fourier Transform Spectrometer (FTS) used for in-field testing of POLARBEAR receiver, an experiment located in Atacama Desert Chile which measures cosmic microwave background (CMB) polarization. The POLARBEAR-FTS (PB-FTS) is a Martin-Puplett interferometer designed to couple Huan Tran Telescope (HTT) on receiver installed. PB-FTS measured spectral response with signal-to-noise ratio >20 ∼69% focal plane detectors due three features: high throughput 15.1 sr cm2, optimized...
We are developing transition edge sensor (TES) bolometer arrays for a new multicolor millimeter-submillimeter camera the Atacama Submillimeter Telescope Experiment located at an altitude of 4860 m in desert. Our goal is to sensitive multi-color observations estimating photometric redshift dusty star-forming distant galaxies and precise measurements properties galaxy clusters through Sunyaev-Zel'dovich effect. will have three bands with center wavelengths 1.1, 0.85, 0.45 mm, respectively. As...
We report a measurement of the E-mode polarization power spectrum cosmic microwave background (CMB) using 150 GHz data taken from July 2014 to December 2016 with POLARBEAR experiment. reach an effective map noise level $32\,\mu\mathrm{K}$-$\mathrm{arcmin}$ across observation area 670 square degrees. measure EE over angular multipole range $500 \leq \ell <3000$, tracing third seventh acoustic peaks high sensitivity. The statistical uncertainty on bandpowers is $\sim 2.3 \mu {\rm K}^2$ at...
POLARBEAR-2 is a new receiver system, which will be deployed on the Simons Array telescope platform, for measurement of Cosmic Microwave Background (CMB) polarization. The science goals with are to characterize B-mode signal both at degree and sub-degree angular-scales. degree-scale polarization data can used quantitative studies inflation, such as reconstruction energy scale inflation. an excellent tracer large-scale structure in universe, lead precise constraints sum neutrino masses. In...
We describe the recent reoptimization of detector array in APEX‐SZ receiver, which is currently operating at APEX telescope Chile. designed to image Sunyaev Zel'dovich effect (SZE). Observations are made a single spectral band centered on 150 GHz, where decrement SZE peaks. The transition‐edge sensor bolometers micro‐fabricated six 55‐element sub arrays, combine form full 330‐element focal plane 280 mK. report newest generation sub‐arrays that use λ/4 silicon‐filled backshort. Compared first...
The E and B Experiment (EBEX) is a balloon-borne polarimeter designed to measure the polarization of cosmic microwave background radiation characterize galactic dust.EBEX was launched December 29, 2012 circumnavigated Antarctica observing ∼6,000 square degrees sky during 11 days at three frequency bands centered around 150, 250 410 GHz.EBEX first experiment operate kilo-pixel array transition-edge sensor bolometers continuously rotating achromatic half-wave plate aboard balloon platform.It...
The E and B Experiment (EBEX) is a balloon-borne polarimeter designed to measure the polarization of cosmic microwave background radiation characterize galactic dust. EBEX was launched December 29, 2012 circumnavigated Antarctica observing $\sim$6,000 square degrees sky during 11 days at three frequency bands centered around 150, 250 410 GHz. first experiment operate kilo-pixel array transition-edge sensor bolometers continuously rotating achromatic half-wave plate aboard balloon platform....
POLARBEAR-2A is the first receiver for Simons Array cosmic microwave background polarization experiment. has transition-edge sensor bolometers on focal plane. Signals from are multiplexed and read out by a single SQUID. The was deployed in late 2018 Atacama, Chile, operation started 2019, where rapid confirmation of correspondence between readout channels important as an initial step performance validation. For this purpose, we devised method using coherent source that allows us to identify...
Abstract P OLARBEAR is a Cosmic Microwave Background radiation (CMB) polarization experiment that located in the Atacama Desert Chile. The scientific goals of are to characterize B -mode signal from gravitational lensing, as well search for signals created by primordial waves (PGWs). Polarbear started observations 2012 and has published series results. These include first measurement nonzero angular auto-power spectrum at sub-degree scales where dominant lensing CMB. In addition, we have...
We report on the development of commercially fabricated multi-chroic antenna coupled Transition Edge Sensor (TES) bolometer arrays for Cosmic Microwave Background (CMB) polarimetry experiments. The orders magnitude increase in detector count next generation CMB experiments require a new approach wafer production to fabrication throughput. We describe collaborative efforts with commercial superconductor electronics facility (SeeQC Inc.) fabricate application. have successfully...