A5086303870- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Superconducting and THz Device Technology
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Satellite Image Processing and Photogrammetry
- Advanced Differential Geometry Research
- Statistical and numerical algorithms
- Dark Matter and Cosmic Phenomena
Johns Hopkins University
2018-2023
Carnegie Mellon University
2015
The Cosmology Large Angular Scale Surveyor (CLASS) observes the polarized cosmic microwave background (CMB) over angular scales of 1$^\circ \lesssim \theta \leq$ 90$^\circ$ with aim characterizing primordial gravitational waves and reionization. We report on on-sky performance CLASS Q-band (40 GHz), W-band (90 dichroic G-band (150/220 GHz) receivers that have been operational at site in Atacama desert since June 2016, May 2018, September 2019, respectively. show noise-equivalent power...
Abstract The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background (CMB) over 75% of sky from Atacama Desert, Chile, at frequency bands centered near 40, 90, 150, and 220 GHz. CLASS measures large angular scale (1° ≲ θ 90°) CMB polarization to constrain tensor-to-scalar ratio r ∼ 0.01 level optical depth last scattering sample variance limit. This paper presents characterization 40 GHz during its first observation era, 2016...
The current and future cosmic microwave background (CMB) experiments fielding kilo-pixel arrays of transition-edge sensor (TES) bolometers require accurate robust gain calibration methods. We simplify refactor the standard TES model to directly relate detector responsivity optical time constant measured $I$ applied bias $I_{\mathrm{b}}$. method developed for Cosmology Large Angular Scale Surveyor (CLASS) bolometer relies on versus voltage ($I$-$V$) measurements acquired daily prior CMB...
Abstract The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background over 75% of sky from Atacama Desert, Chile, at frequency bands centered near 40, 90, 150, and 220 GHz. This paper describes CLASS data pipeline maps for 40 GHz observations conducted 2016 August to 2022 May. We demonstrate how well survey strategy, with rapid (∼10 Hz) front-end modulation, recovers large-scale Galactic polarization signal ground: mapping transfer...
The reionization optical depth is the most poorly determined of six $\Lambda$CDM parameters fit to CMB anisotropy data. Instrumental noise and systematics have prevented uncertainties from reaching their cosmic variance limit. At present, datasets providing statistical constraining power are WMAP, Planck LFI, HFI full-sky polarization maps. As reprocessed data with reduced not yet publicly unavailable, we examine determinations $\tau$ using 9-year WMAP 2015 LFI data, an emphasis on...
The Cosmology Large Angular Scale Surveyor (CLASS) is a four-telescope array observing the largest angular scales ($2 \lesssim \ell 200$) of cosmic microwave background (CMB) polarization. These encode information about reionization and inflation during early universe. instrument stability necessary to observe these from ground achieved through use variable-delay polarization modulator (VPM) as first optical element in each CLASS telescopes. Here we develop demodulation scheme used extract...
We investigate the utility and robustness of a new statistic, $\omega_{\ell}\left(r_{c}\right)$, for analyzing Baryon Acoustic Oscillations (BAO). apply introduced in Xu et al. (2010), to mocks data from Sloan Digital Sky Survey (SDSS)-III Oscillation Spectroscopic (BOSS) included SDSS Data Release Eleven (DR11). fit anisotropic clustering using monopole quadrupole $\omega_{\ell}\left(r_{c}\right)$ statistic manner similar conventional multipole fitting methods correlation function as...
The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background over 75\% of sky from Atacama Desert, Chile, at frequency bands centered near 40, 90, 150, and 220~GHz. This paper describes CLASS data pipeline maps for 40~GHz observations conducted August 2016 to May 2022. We demonstrate how well survey strategy, with rapid ($\sim10\,\mathrm{Hz}$) front-end modulation, recovers large-scale Galactic polarization signal ground: mapping...
Abstract Using Planck polarization data, we search for and constrain spatial variations of the polarized dust foreground cosmic microwave background (CMB) observations, specifically in its spectral index, β d . Failure to account such will cause errors cleaning that propagate into on cosmological parameter recovery from cleaned CMB map. It is unclear how robust prior studies data constrained are due challenges with noise modeling, residual systematics, priors. To clarify constraints...