CLASS Angular Power Spectra and Map-component Analysis for 40 GHz Observations through 2022

Eimer, Joseph R.; Li 李, Yunyang 云炀; Brewer, Michael K.; Shi 时, Rui 瑞; Ali, Aamir; Appel, John W.; Bennett, Charles L.; Bruno, Sarah Marie; Bustos, Ricardo; Chuss, David T.; Cleary, Joseph; Dahal, Sumit; Datta, Rahul; Denes Couto, Jullianna; Denis, Kevin L.; Dünner, Rolando; Essinger-Hileman, Thomas; Fluxá, Pedro; Hubmayer, Johannes; Harrington, Kathleen; Iuliano, Jeffrey; Karakla, John; Marriage, Tobias A.; Núñez, Carolina; Parker, Lucas; Petroff, Matthew A.; Reeves, Rodrigo A.; Rostem, Karwan; Valle, Deniz A. N.; Watts, Duncan J.; Weiland, Janet L.; Wollack, Edward J.; Xu 徐, Zhilei 智磊; Zeng, Lingzhen

doi:10.3847/1538-4357/ad1abf

Cited by 7 publications

(16 citation statements)

References 107 publications

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“…Much remains to be learned about characterizing low-frequency foregrounds' spectral and spatial behaviors (Planck Collaboration et al 2016). WMAP has observed substantial amounts of polarized foreground emission due to synchrotron radiation, even at high Galactic latitudes (Page et al 2007), and this has been confirmed by other experiments (Krachmalnicoff et al 2018;Eimer et al 2024). Kogut et al (2007) have observed a flattening of the synchrotron spectral index closer to the Galactic plane; however, Choi & Page (2015) have attributed this effect to the spatial correlation of dust and synchrotron.…”

Section: Introductionmentioning

confidence: 53%

Design and Performance of a 30/40 GHz Diplexed Focal Plane for the BICEP Array

Shiu,

Soliman,

O’Brient

et al. 2024

ApJS

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We demonstrate a wideband diplexed focal plane suitable for observing low-frequency foregrounds that are important for cosmic microwave background polarimetry. The antenna elements are composed of slotted bowtie antennas with 60% bandwidth that can be partitioned into two bands. Each pixel is composed of two interleaved 12 × 12 pairs of linearly polarized antenna elements forming a phased array, designed to synthesize a symmetric beam with no need for focusing optics. The signal from each antenna element is captured in-phase and uniformly weighted by a microstrip summing tree. The antenna signal is diplexed into two bands through the use of two complementary, six-pole Butterworth filters. This filter architecture ensures a contiguous impedance match at all frequencies, and thereby achieves minimal reflection loss between both bands. Subsequently, out-of-band rejection is increased with a bandpass filter and the signal is then deposited on a transition-edge sensor bolometer island. We demonstrate the performance of this focal plane with two distinct bands, 30 and 40 GHz, each with a bandwidth of ∼20 and 15 GHz, respectively. The unequal bandwidths between the two bands are caused by an unintentional shift in diplexer frequency from its design values. The end-to-end optical efficiency of these detectors is relatively modest, at 20%–30%, with an efficiency loss due to an unknown impedance mismatch in the summing tree. Far-field beam maps show good optical characteristics, with edge pixels having no more than ∼5% ellipticity and ∼10%–15% peak-to-peak differences for A–B polarization pairs.

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Section: Introductionmentioning

confidence: 53%

Design and Performance of a 30/40 GHz Diplexed Focal Plane for the BICEP Array

Shiu,

Soliman,

O’Brient

et al. 2024

ApJS

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“…Full sky implementations have been explored previously (e.g., Wright et al 1996;Tegmark 1997). More recently there are examples of implementations at smaller angular scales (Aiola et al 2020;Li et al 2023;Eimer et al 2024;Qu et al 2024).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

SOFIA/HAWC+ Far-infrared Polarimetric Large-area CMZ Exploration Survey. III. Full Survey Data Set

Paré,

Butterfield,

Chuss

et al. 2024

ApJ

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We present the second data release (DR2) of the Far-InfraREd Polarimetric Large-Area CMZ Exploration (FIREPLACE) survey. This survey utilized the Stratospheric Observatory for Infrared Astronomy High-resolution Airborne Wideband Camera plus instrument at 214 μm (E band) at a resolution of 19.″6 to observe thermal polarized dust emission throughout the Central Molecular Zone (CMZ). DR2 consists of observations obtained in 2022 covering the region of the CMZ extending from the Brick to the Sgr C molecular clouds (corresponding to a 1° × 0.°75 region of the sky). We combine DR2 with the first FIREPLACE data release (DR1) to obtain full coverage of the CMZ (a 1.°5 × 0.°75 region of the sky). After applying total and polarized intensity significance cuts on the full FIREPLACE data set, we obtain ∼64,000 Nyquist-sampled polarization pseudovectors. The distribution of polarization pseudovectors confirms a bimodal distribution in the CMZ magnetic field orientations, recovering field components that are oriented predominantly parallel or perpendicular to the Galactic plane. This distribution of orientations is similar to what was observed in DR1 and other studies. We also inspect the magnetic fields toward a set of prominent CMZ molecular clouds (the Brick, Three Little Pigs, 50 and 20 km s−1 clouds, circumnuclear disk, CO 0.02-0.02, and Sgr C), revealing spatially varying magnetic fields having orientations that generally trace the total intensity morphologies of the clouds. We find evidence that compression from stellar winds and shear from tidal forces are prominent mechanisms influencing the structure of the magnetic fields.

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“…Other Era 1 papers address telescope calibration, efficiency, and sensitivity (Appel et al 2019(Appel et al , 2022; circular polarization (Padilla et al 2020;Petroff et al 2020); and polarization modulation and long-timescale instrument stability (Harrington et al 2021). The CLASS data reduction pipeline and polarization maps at 40 GHz are presented in Li et al (2023); angular power spectra and map-based results are presented in Eimer et al (2024). Measurements of the disk-averaged absolute Venus brightness temperature using CLASS have been reported in Dahal et al (2021) and Dahal et al (2023).…”

Section: Introductionmentioning

confidence: 99%

Cosmology Large Angular Scale Surveyor (CLASS): 90 GHz Telescope Pointing, Beam Profile, Window Function, and Polarization Performance

Datta,

Brewer,

Couto

et al. 2024

ApJS

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The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background (CMB) over ∼75% of the sky from the Atacama Desert, Chile, at frequency bands centered near 40, 90, 150, and 220 GHz. CLASS measures the large angular scale CMB polarization to constrain the tensor-to-scalar ratio and the optical depth to last scattering. This paper presents the optical characterization of the 90 GHz telescope. Observations of the Moon establish the pointing while dedicated observations of Jupiter are used for beam calibration. The standard deviations of the pointing error in azimuth, elevation, and boresight angle are 1.′3, 2.′1, and 2.′0, respectively, over the first 3 yr of observations. This corresponds to a pointing uncertainty ∼7% of the beam’s full width at half-maximum (FWHM). The effective azimuthally symmetrized instrument 1D beam estimated at 90 GHz has an FWHM of 0.°620 ± 0.°003 and a solid angle of 138.7 ± 0.6(stats.) ± 1.1(sys.) μsr integrated to a radius of 4°. The corresponding beam window function drops to b ℓ 2 = 0.93 , 0.71 , 0.14 at ℓ = 30, 100, 300, respectively. Far-sidelobes are studied using detector-centered intensity maps of the Moon and measured to be at a level of 10−3 or below relative to the peak. The polarization angle of Tau A estimated from preliminary survey maps is 149°.6 ± 0°.2(stats.) in equatorial coordinates. The instrumental temperature-to-polarization (T → P) leakage fraction, inferred from per-detector demodulated Jupiter scan data, has a monopole component at the level of 1.7 × 10−3, a dipole component with an amplitude of 4.3 × 10−3, with no evidence of quadrupolar leakage.

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CLASS Angular Power Spectra and Map-component Analysis for 40 GHz Observations through 2022

Cited by 7 publications

References 107 publications

Design and Performance of a 30/40 GHz Diplexed Focal Plane for the BICEP Array

Design and Performance of a 30/40 GHz Diplexed Focal Plane for the BICEP Array

SOFIA/HAWC+ Far-infrared Polarimetric Large-area CMZ Exploration Survey. III. Full Survey Data Set

Cosmology Large Angular Scale Surveyor (CLASS): 90 GHz Telescope Pointing, Beam Profile, Window Function, and Polarization Performance

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