J. M. Kovac
A5043290359- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Superconducting and THz Device Technology
- Geophysics and Gravity Measurements
- Dark Matter and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Computational Physics and Python Applications
- Geomagnetism and Paleomagnetism Studies
- Material Dynamics and Properties
- Particle accelerators and beam dynamics
- Astrophysics and Star Formation Studies
- Coal and Coke Industries Research
- Superconducting Materials and Applications
- Rheology and Fluid Dynamics Studies
- Particle physics theoretical and experimental studies
- Particle Accelerators and Free-Electron Lasers
- Spacecraft Design and Technology
- Scientific Research and Discoveries
- Theoretical and Computational Physics
- Antenna Design and Optimization
- Microwave Engineering and Waveguides
- Stellar, planetary, and galactic studies
Harvard University Press
2010-2025
Center for Astrophysics Harvard & Smithsonian
2015-2024
Utrecht University
2024
Harvard University
2011-2023
California Institute of Technology
2004-2022
University of British Columbia
2022
University of Illinois Urbana-Champaign
2022
Institut Laue-Langevin
2020
Jet Propulsion Laboratory
2009-2020
Stanford University
2009-2018
(abridged for arXiv) We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search signal of inflationary gravitational waves in B-mode power spectrum around $\ell\sim80$. The telescope comprised 26 cm aperture all-cold refracting optical system equipped with focal plane 512 antenna coupled transition edge sensor 150 GHz bolometers each temperature sensitivity $\approx300\mu\mathrm{K}_\mathrm{CMB}\sqrt{s}$. observed South Pole...
We present measurements of anisotropy in the cosmic microwave background (CMB) from first season observations with Degree Angular Scale Interferometer (DASI). The instrument was deployed at South Pole austral summer 1999-2000, and we made throughout following winter. a measurement CMB angular power spectrum range 100 < l 900 nine bands fractional uncertainties 10%-20% dominated by sample variance. In this paper, review formalism used analysis, particular use constraint matrices to project...
We present results from an analysis of all data taken by the BICEP2, Keck Array, and BICEP3 CMB polarization experiments up to including 2018 observing season. add additional Array observations at 220 GHz 95 previous 95/150/220 dataset. The Q/U maps now reach depths 2.8, 8.8 μK_{CMB} arcmin 95, 150, GHz, respectively, over effective area ≈600 square degrees ≈400 150 GHz. achieve a signal-to-noise ratio on polarized dust emission exceeding that Planck 353 take auto- cross-spectra between...
We present results from an analysis of all data taken by the BICEP2 and Keck Array cosmic microwave background (CMB) polarization experiments up to including 2014 observing season. This includes first observations at 95 GHz. The maps reach a depth 50 nK deg in Stokes Q U 150 GHz band 127 band. take auto- cross-spectra between these publicly available WMAP Planck frequencies 23 353 An excess over lensed ΛCDM is detected modest significance 95×150 BB spectrum, consistent with dust contribution...
This book lays out the scientific goals to be addressed by next-generation ground-based cosmic microwave background experiment, CMB-S4, envisioned consist of dedicated telescopes at South Pole, high Chilean Atacama plateau and possibly a northern hemisphere site, all equipped with new superconducting cameras. CMB-S4 will dramatically advance cosmological studies crossing critical thresholds in search for B-mode polarization signature primordial gravitational waves, determination number...
We present results from an analysis of all data taken by the bicep2/Keck CMB polarization experiments up to and including 2015 observing season. This includes first Keck Array observations at 220 GHz additional 95 150 GHz. The Q U maps reach depths 5.2, 2.9, 26 μKCMB arcmin 95, 150, GHz, respectively, over effective area ≈400 square degrees. achieve a signal noise on polarized dust emission approximately equal that Planck 353 take auto cross spectra between these publicly available WMAP...
We report measurements of anisotropy in the cosmic microwave background radiation over multipole range l ~ 200-3500 with Cosmic Background Imager based on deep observations three fields. These results confirm drop power increasing first reported earlier this instrument and extend decline out to 2000. The is consistent predicted damping primary anisotropies. At larger multipoles, = 2000-3500, 3.1 σ greater than standard models for intrinsic 3.5 zero. This excess not expected levels residual...
The Degree Angular Scale Interferometer (DASI) has measured the power spectrum of cosmic microwave background anisotropy over range spherical harmonic multipoles 100 < l 900. We compare these data, in combination with COBE DMR results, to a seven-dimensional grid adiabatic cold dark matter (CDM) models. Adopting priors h > 0.45 and 0.0 ≤ τc 0.4, we find that total density universe Ωtot = 1.04 ± 0.06 spectral index initial scalar fluctuations ns 1.01 accordance predictions inflationary...
Using the Cosmic Background Imager (CBI), a 13-element interferometer array operating in 26-36 GHz frequency band, we have observed 40 deg2 of sky three pairs fields, each ~145' × 165', using overlapping pointings (mosaicking). We present images and power spectra cosmic microwave background radiation these mosaic fields. remove ground other low-level contaminating signals by differencing matched observations fields pair. The primary foreground contamination is due to point sources (radio...
Polarization observations of the cosmic microwave background with Cosmic Background Imager from September 2002 to May 2004 provide a significant detection E-mode polarization and reveal an angular power spectrum polarized emission showing peaks valleys that are shifted in phase by half cycle relative those total intensity spectrum. This key agreement between observed predicted on basis provides support for standard model cosmology, which dark matter energy dominant constituents, geometry is...
We present an improved analysis of the final dataset from QUaD experiment. Using technique to remove ground contamination, we double effective sky area and hence increase precision our CMB power spectrum measurements by ~30% versus that previously reported. In addition, have modeling instrument beams reduced absolute calibration uncertainty 5% 3.5% in temperature. The robustness results is confirmed through extensive jackknife tests way agreement find between two fully independent pipelines....
Several attempts have been made to account for polymer chain stiffness or excluded volume effects in non-Newtonian viscosity theory with the use of a modified Gaussian probability intrachain distances. This method is here tested freely rotating by an application equilibrium expectation end-to-end vector R presence external potential −R· f. The parameters are varied as f increases keep estimates bond length and angle constant. Numerical tests limits jointed worm chain, approach found work very well.
We report on the design and performance of BICEP2 instrument its three-year data set. was designed to measure polarization cosmic microwave background (CMB) angular scales 1 5 degrees ($\ell$=40-200), near expected peak B-mode signature primordial gravitational waves from inflation. Measuring B-modes requires dramatic improvements in sensitivity combined with exquisite control systematics. The telescope observed South Pole a 26~cm aperture cold, on-axis, refractive optics. also adopted new...
Background Imaging of Cosmic Extragalactic Polarization (Bicep) is a bolometric polarimeter designed to measure the inflationary B-mode polarization cosmic microwave background (CMB) at degree angular scales. During three seasons observing South Pole (2006 through 2008), Bicep mapped ∼2% sky chosen be uniquely clean polarized foreground emission. Here, we present initial results derived from subset data acquired during first two years. We maps temperature, Stokes Q and U, E B modes,...
The Keck Array is a system of cosmic microwave background polarimeters, each similar to the Bicep2 experiment. In this paper we report results from 2012 2013 observing seasons, during which consisted five receivers all operating in same (150 GHz) frequency band and field as Bicep2. We again find an excess B-mode power over lensed-ΛCDM expectation >5σ range 30 < ℓ 150 confirm that not due systematics using jackknife tests simulations based on detailed calibration measurements. map difference...
We report on the design and performance of BICEP3 instrument its first three-year data set collected from 2016 to 2018. is a 52cm aperture, refracting telescope designed observe polarization cosmic microwave background (CMB) degree angular scales at 95GHz. It started science observation South Pole in with 2400 antenna-coupled transition-edge sensor (TES) bolometers. The receiver demonstrated new technologies such as large-diameter alumina optics, Zotefoam infrared filters, flux-activated...
We present the analysis of complete 3 yr data set obtained with Degree Angular Scale Interferometer (DASI) polarization experiment, operating from Amundsen-Scott South Pole research station. New at end 2002 austral winter and throughout 2003 season were added to which first detection cosmic microwave background (CMB) radiation was reported. The combined supports, increased statistical power, all conclusions drawn initial set. In particular, E-mode is 6.3 σ confidence level, TE...
We report results from the second and third seasons of observation with QUaD experiment. Angular power spectra Cosmic Microwave Background are derived for both temperature polarization at 100 GHz 150 GHz, as cross frequency spectra. All subjected to an extensive set jackknife tests probe possible systematic contamination. For implemented data cuts processing technique such contamination is undetectable. analyze difference map formed between bands find no evidence foreground in polarization....
We constrain parity-violating interactions to the surface of last scattering using spectra from QUaD experiment's second and third seasons observations by searching for a possible systematic rotation polarization directions cosmic microwave background photons. measure angle due such "cosmological birefringence" be 0.55 degrees +/-0.82 (random) +/-0.5 (systematic) QUaD's 100 150 GHz temperature-curl gradient-curl over multipole range 200<l<2000, consistent with null, Lorentz-violating <2 x...
The nonlinear configurational diffusion equation is formulated with bond vector coordinates. Primarily the treatment focuses on low amplitude oscillatory shear flow of freely jointed chain, but high frequency limit also constraint constant angles, and calculable fairly readily for a rotating chain or rotational isomeric model. only numerical result given here concerns [η]N∞ chains N bonds. We find by perturbation theory that ≃ [η]1∞ N[1+(N−1)/(6N)+⋯] (for concentration measured in...
Bicep3 is a 550 mm-aperture refracting telescope for polarimetry of radiation in the cosmic microwave background at 95 GHz.It adopts methodology Bicep1, Bicep2 and Keck Array experiments -it possesses sufficient resolution to search signatures inflation-induced gravitational-wave while utilizing compact design ease construction facilitate characterization mitigation systematics.However, represents significant breakthrough per-receiver sensitivity, with focal plane area 5× larger than...