A5025883011- Radio Astronomy Observations and Technology
- Superconducting and THz Device Technology
- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Physics of Superconductivity and Magnetism
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- Calibration and Measurement Techniques
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced MIMO Systems Optimization
- Precipitation Measurement and Analysis
- Soil Moisture and Remote Sensing
- Thermal Radiation and Cooling Technologies
- Solar and Space Plasma Dynamics
- Advanced Frequency and Time Standards
- Spectroscopy and Quantum Chemical Studies
- Remote Sensing and LiDAR Applications
- Antenna Design and Optimization
- Spectroscopy Techniques in Biomedical and Chemical Research
- Smart Agriculture and AI
- Particle accelerators and beam dynamics
- Scientific Measurement and Uncertainty Evaluation
Technical University of Darmstadt
2025
University of British Columbia
2006-2013
SCUBA-2 is an innovative 10000 pixel bolometer camera operating at submillimetre wavelengths on the James Clerk Maxwell Telescope (JCMT). The has capability to carry out wide-field surveys unprecedented depths, addressing key questions relating origins of galaxies, stars and planets. With two imaging arrays working simultaneously in atmospheric windows 450 850 microns, vast increase count means that maps sky 100-150 times faster than previous SCUBA instrument. In this paper we present...
We present constraints on cosmological and astrophysical parameters from high-resolution microwave background maps at 148 GHz 218 made by the Atacama Cosmology Telescope (ACT) in three seasons of observations 2008 to 2010. A model primary secondary foreground is fit map power spectra lensing deflection spectrum, including contributions both thermal Sunyaev-Zeldovich (tSZ) effect kinematic (kSZ) effect, Poisson correlated anisotropy unresolved infrared sources, radio correlation between tSZ...
We present cosmological parameters derived from the angular power spectrum of cosmic microwave background (CMB) radiation observed at 148 GHz and 218 over 296 deg2 with Atacama Cosmology Telescope (ACT) during its 2008 season. ACT measures fluctuations scales 500 < ℓ 10, 000. fit a model for lensed CMB, Sunyaev–Zel'dovich (SZ), foreground contribution to spectra, including thermal kinetic SZ, Poisson radio infrared point sources, clustered sources. At = 3000, about half comes primary CMB...
We report on 23 clusters detected blindly as Sunyaev–ZEL'DOVICH (SZ) decrements in a 148 GHz, 455 deg2 map of the southern sky made with data from Atacama Cosmology Telescope 2008 observing season. All SZ detections announced this work have confirmed optical counterparts. Ten are new discoveries. One newly discovered cluster, ACT-CL J0102−4915, redshift 0.75 (photometric), has an decrement comparable to most massive systems at lower redshifts. Simulations cluster recovery method reproduce...
We present measurements of the cosmic microwave background (CMB) power spectrum made by Atacama Cosmology Telescope at 148 GHz and 218 GHz, as well cross-frequency between two channels. Our results clearly show second through seventh acoustic peaks in CMB spectrum. The these higher-order provide an additional test {\Lambda}CDM cosmological model. At l > 3000, we detect excess primary anisotropy CMB. lower multipoles 500 < find evidence for gravitational lensing 2.8{\sigma} level. also a low...
We present constraints on cosmological parameters based a sample of Sunyaev-Zel'dovich-selected galaxy clusters detected in millimeter-wave survey by the Atacama Cosmology Telescope. The cluster used this analysis consists 9 optically-confirmed high-mass comprising high-significance end total identified 455 square degrees sky surveyed during 2008 at 148 GHz. focus most massive systems to reduce degeneracy between unknown astrophysics and cosmology derived from SZ surveys. describe scaling...
We present a measurement of the angular power spectrum cosmic microwave background (CMB) radiation observed at 148 GHz. The uses maps with 1.4' resolution made data from Atacama Cosmology Telescope (ACT). observations cover 228 square degrees southern sky, in 4.2-degree-wide strip centered on declination 53 South. CMB arcminute scales is particularly sensitive to Silk damping scale, Sunyaev-Zel'dovich (SZ) effect galaxy clusters, and emission by radio sources dusty galaxies. After masking...
We present a description of the data reduction and mapmaking pipeline used for 2008 observing season Atacama Cosmology Telescope (ACT). The presented here at 148 GHz represent 12% 90 TB collected by ACT from 2007 to 2010. In we observed 136 days, producing total 1423 hours (11 band only), with daily average 10.5 observation. From these, 1085 were devoted 850 deg^2 stripe (11.2 9.1 deg) centered on declination -52.7 deg, while 175 280 (4.5 4.8 celestial equator. discuss sources statistical...
The Atacama Cosmology Telescope (ACT) is currently observing the cosmic microwave background with arcminute resolution at 148 GHz, 218 and 277 GHz. In this paper, we present ACT's first results. Data have been analyzed using a maximum-likelihood map-making method which uses B-splines to model remove atmospheric signal. It has used make high-precision beam maps from determine experiment's window functions. This information directly impacts all subsequent analyses of data. We also map sample...
We report on extragalactic sources detected in a 455 square-degree map of the southern sky made with data at frequency 148 GHz from Atacama Cosmology Telescope 2008 observing season. provide catalog 157 flux densities spanning two orders magnitude: 15 to 1500 mJy. Comparison other catalogs shows that 98% ACT detections correspond lower radio frequencies. Three appear be associated brightest cluster galaxies low redshift X-ray selected galaxy clusters. Estimates mm-wave spectral indices and...
We describe SPIDER, a balloon-borne instrument to map the polarization of millimeter-wave sky with degree angular resolution. Spider consists six monochromatic refracting telescopes, each illuminating focal plane large-format antenna-coupled bolometer arrays. A total 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. cold half-wave plate aperture telescope modulates incoming light control systematics. SPIDER's first...
We experimentally demonstrated and thoroughly investigated the up-conversion of midinfrared signals from nonlinear spectroscopy in a molecular gas to regime shorter wavelength improve features applicability such sensitive techniques for detection species. In particular, we apply sum-frequency mixing (SFM) weak resonantly enhanced third-harmonic-generation (THG) with strong nanosecond pump pulses, implemented conventional bulk crystal. The conversion efficiency reaches 26%, i.e., substantial...
We present the results of characterization measurements on a 1280 pixel superconducting bolometer array designed for operation at wavelengths around 450 μm. The is prototype sub-arrays which will form focal plane SCUBA-2 sub-mm camera, being built James Clerk Maxwell Telescope (JCMT) in Hawaii. With over 10 000 pixels total, it provide huge improvement both sensitivity and mapping speed existing instruments. consists molybdenum-copper bi-layer TES (transition edge sensor) pixels, bonded to...
We present a new calibration method based on cross-correlations with WMAP and apply it to data from the Atacama Cosmology Telescope (ACT). ACT's observing strategy map making procedure allows an unbiased reconstruction of modes in maps over wide range multipoles. By directly matching ACT observations multipole 400 < ell 1000, we determine absolute uncertainty 2% temperature. The precise measurement error impacts uncertainties cosmological parameters estimated power spectra. also combined...
The Bicep2 and Keck Array experiments are designed to measure the polarization of cosmic microwave background (CMB) on angular scales 2-4 degrees (ℓ = 50–100). This is region in which <i>B</i>-mode signal, a signature prediction inflation, expected peak. was deployed South Pole at end 2009 middle its third year observing with 500 polarization-sensitive detectors 150 GHz. 2010, initially three receivers—each similar Bicep2. An additional two receivers have been added during 2011-12 summer. We...
The Atacama Cosmology Telescope observes the Cosmic Microwave Background with arcminute resolution from desert in Chile. For first observing season one array of 32 x Transition Edge Sensor (TES) bolometers was installed primary ACT receiver, Millimeter Bolometer Array Camera (MBAC). In next season, three independent arrays working at 145, 220 and 280 GHz will be MBAC. bolometer are each coupled to a time-domain multiplexer developed National Institute Standard Technology, Boulder, which...
Between the BICEP2 and Keck Array experiments, we have deployed over 1500 dual polarized antenna coupled bolometers to map Cosmic Microwave Background's polarization. We been able rapidly deploy these detectors because they are completely planar with an integrated phased-array antenna. Through our experience in learned of several challenges this technology- specifically beam synthesis antenna- paper report on how modified designs mitigate challenges. In particular, discus differential...
The Atacama Cosmology Telescope (ACT) aims to measure the Cosmic Microwave Background (CMB) temperature anisotropies on arcminute scales. primary receiver for ACT is Millimeter Bolometer Array Camera (MBAC). MBAC comprised of three 32×32 transition edge sensor (TES) bolometer arrays, each observing sky with an independent set band-defining filters. arrays will be largest pop-up detector fielded, and among TES built. Prior its assembly into array installation MBAC, a column 32 bolometers...
The Keck Array (SPUD) began observing the cosmic microwave background's polarization in winter of 2011 at South Pole.The follows success predecessor experiments Bicep and Bicep2, 1 using five on-axis refracting telescopes.These have a combined imaging array 2500 antenna-coupled TES bolometers read with SQUID-based time domain multiplexing system.We will discuss detector noise optimization readout.The achieved sensitivity is 11.5 µK CM B √ s 2012 configuration.
We report on the preliminary detector performance of Bicep2 mm-wave polarimeter, deployed in 2009 to South Pole. is currently imaging polarization cosmic microwave background at 150 GHz using an array 512 antenna-coupled superconducting bolometers. The antennas, band-defining filters and transition edge sensor (TES) bolometers are photolithographically fabricated 4 silicon tiles. Each tile consists 8×8 grid ~7 mm spatial pixels, for a total 256 pairs. A pixel contains 2 sets orthogonal...
The Millimeter Bolometer Array Camera (MBAC) was commissioned in the fall of 2007 on new 6-meterAtacama Cosmology Telescope (ACT). MBAC ACT will map temperature anisotropies theCosmic Microwave Background (CMB) with arc-minute resolution. For this first observing season, MBACcontained a diffraction-limited, 32 by element, focal plane array Transition Edge Sensor (TES) bolometersfor observations at 145 GHz. This coupled to telescope series cold, refractive, reimagingoptics. To meet...
Spider is a balloon-borne instrument designed to map the polarization of cosmic microwave background (CMB) with degree-scale resolution over large fraction sky. Spider's main goal measure amplitude primordial gravitational waves through their imprint on CMB if tensor-to-scalar ratio, r, greater than 0.03. To achieve this goal, instrumental systematic errors must be controlled unprecedented accuracy. Here, we build previous work use simulations observations examine impact several effects that...
SCUBA-2 is a state of the art 10,000 pixel submillimeter camera installed and being commissioned at James Clerk Maxwell Telescope (JCMT) providing wide-field simultaneous imaging wavelengths 450 850 microns. At each wavelength there are four 32 by 40 sub-arrays superconducting Transition Edge Sensor (TES) bolometers, packaged with inline SQUID multiplexed readout amplifier. In this paper we present results characterising individual 1280 bolometer science grade sub-arrays, both in dedicated...