Browsing by Author "Nunez, Carolina"

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    CLASS Angular Power Spectra and Map-component Analysis for 40 GHz Observations through 2022
    (2024) Eimer, Joseph R.; Li, Yuyang; Brewer, Michael K.; Shi, Rui; 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.; Dunner, Rolando; Essinger-Hileman, Thomas; Fluxa, Pedro; Hubmayer, Johannes; Harrington, Kathleen; Iuliano, Jeffrey; Karakla, John; Marriage, Tobias A.; Nunez, 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, Zhilei; Zeng, Lingzhen
    Measurement of the largest angular scale (l < 30) features of the cosmic microwave background (CMB) polarization is a powerful way to constrain the optical depth to reionization and search for the signature of inflation through the detection of primordial B-modes. We present an analysis of maps covering 73.6% of the sky made from the 40 GHz channel of the Cosmology Large Angular Scale Surveyor (CLASS) from 2016 August to 2022 May. Taking advantage of the measurement stability enabled by front-end polarization modulation and excellent conditions from the Atacama Desert, we show this channel achieves higher sensitivity than the analogous frequencies from satellite measurements in the range 10 < l < 100. Simulations show the CLASS linear (circular) polarization maps have a white noise level of 125(130)mu Karcmin . We measure the Galaxy-masked EE and BB spectra of diffuse synchrotron radiation and compare to space-based measurements at similar frequencies. In combination with external data, we expand measurements of the spatial variations of the synchrotron spectral energy density (SED) to include new sky regions and measure the diffuse SED in the harmonic domain. We place a new upper limit on a background of circular polarization in the range 5 < l < 125 with the first bin showing D- l < 0.023 mu K-CMB(2) at 95% confidence. These results establish a new standard for recovery of the largest-scale CMB polarization from the ground and signal exciting possibilities when the higher sensitivity and higher-frequency CLASS channels are included in the analysis.
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    CLASS Data Pipeline and Maps for 40 GHz Observations through 2022
    (2023) Li, Yunyang; Eimer, Joseph R.; Osumi, Keisuke; Appel, John W.; Brewer, Michael K.; Ali, Aamir; Bennett, Charles L.; Bruno, Sarah Marie; Bustos, Ricardo; Chuss, David T.; Cleary, Joseph; Couto, Jullianna Denes; Dahal, Sumit; Datta, Rahul; Denis, Kevin L.; Dunner, Rolando; Espinoza, Francisco; Essinger-Hileman, Thomas; Rojas, Pedro Fluxa; Harrington, Kathleen; Iuliano, Jeffrey; Karakla, John; Marriage, Tobias A.; Miller, Nathan J.; Novack, Sasha; Nunez, Carolina; Petroff, Matthew A.; Reeves, Rodrigo A.; Rostem, Karwan; Shi, Rui; Valle, Deniz A. N.; Watts, Duncan J.; Weiland, Janet L.; Wollack, Edward J.; Xu, Zhilei; Zeng, Lingzhen; CLASS Collaboration
    The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background over 75% of the sky from the Atacama Desert, Chile, at frequency bands centered near 40, 90, 150, and 220 GHz. This paper describes the CLASS data pipeline and maps for 40 GHz observations conducted from 2016 August to 2022 May. We demonstrate how well the CLASS survey strategy, with rapid (similar to 10 Hz) front-end modulation, recovers the large-scale Galactic polarization signal from the ground: the mapping transfer function recovers similar to 67% (85%) of EE and BB (VV) power at l = 20 and similar to 35% (47%) at l = 10. We present linear and circular polarization maps over 75% of the sky. Simulations based on the data imply the maps have a white noise level of 110 mu Karcmin and correlated noise component rising at low-l as l -2.4. The transfer-function-corrected low-l component is comparable to the white noise at the angular knee frequencies of l approximate to 18 (linear polarization) and l approximate to 12 (circular polarization). Finally, we present simulations of the level at which expected sources of systematic error bias the measurements, finding subpercent bias for the Lambda cold dark matter EE power spectra. Bias from E-to-B leakage due to the data reduction pipeline and polarization angle uncertainty approaches the expected level for an r = 0.01 BB power spectrum. Improvements to the instrument calibration and the data pipeline will decrease this bias.
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    Cosmology Large Angular Scale Surveyor (CLASS): 90 GHz Telescope Pointing, Beam Profile, Window Function, and Polarization Performance
    (2024) Datta, Rahul; Brewer, Michael K.; Couto, Jullianna Denes; Eimer, Joseph; Li, Yunyang; Xu, Zhilei; Ali, Aamir; Appel, John W.; Bennett, Charles L.; Bustos, Ricardo; Chuss, David T.; Cleary, Joseph; Dahal, Sumit; Inostroza, Francisco Raul Javier Espinoza; Essinger-Hileman, Thomas; Fluxa, Pedro; Harrington, Kathleen; Helson, Kyle; Iuliano, Jeffrey; Karakla, John; Marriage, Tobias A.; Novack, Sasha; Nunez, Carolina; Padilla, Ivan L.; Parker, Lucas; Petroff, Matthew A.; Reeves, Rodrigo; Rostem, Karwan; Shi, Rui; Valle, Deniz A. N.; Watts, Duncan J.; Weiland, Janet L.; Wollack, Edward J.; Zeng, Lingzhen
    The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background (CMB) over similar to 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 similar to 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.degrees 620 +/- 0.degrees 003 and a solid angle of 138.7 +/- 0.6(stats.) +/- 1.1(sys.) mu sr integrated to a radius of 4 degrees. The corresponding beam window function drops to b & ell;2=0.93,0.71,0.14 at & ell; = 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 degrees.6 +/- 0 degrees.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 x 10-3, a dipole component with an amplitude of 4.3 x 10-3, with no evidence of quadrupolar leakage.
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    COVID-19-Associated Mold Infection in Critically Ill Patients, Chile
    (2021) Rabagliati, Ricardo; Rodriguez, Nicolas; Nunez, Carolina; Huete, Alvaro; Bravo, Sebastian; Garcia, Patricia
    Patients with severe coronavirus disease (COVID-19) may have COVID-19-associated invasive mold infection (CAIMI) develop. We report 16 cases of CAIMI among 146 nonimmunocompromised patients with severe COVID-19 at an academic hospital in Santiago, Chile. These rates correspond to a CAIMI incidence of 11%; the mortality rate for these patients was 31.2%.
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    Four-year Cosmology Large Angular Scale Surveyor (CLASS) Observations: On-sky Receiver Performance at 40, 90, 150, and 220 GHz Frequency Bands
    (2022) Dahal, Sumit; Appel, John W.; Datta, Rahul; Brewer, Michael K.; Ali, Aamir; Bennett, Charles L.; Bustos, Ricardo; Chan, Manwei; Chuss, David T.; Cleary, Joseph; Couto, Jullianna D.; Denis, Kevin L.; Dunner, Rolando; Eimer, Joseph; Espinoza, Francisco; Essinger-Hileman, Thomas; Golec, Joseph E.; Harrington, Kathleen; Helson, Kyle; Iuliano, Jeffrey; Karakla, John; Li, Yunyang; Marriage, Tobias A.; McMahon, Jeffrey J.; Miller, Nathan J.; Novack, Sasha; Nunez, Carolina; Osumi, Keisuke; Padilla, Ivan L.; Palma, Gonzalo A.; Parker, Lucas; Petroff, Matthew A.; Reeves, Rodrigo; Rhoades, Gary; Rostem, Karwan; Valle, Deniz A. N.; Watts, Duncan J.; Weiland, Janet L.; Wollack, Edward J.; Xu, Zhilei
    The Cosmology Large Angular Scale Surveyor (CLASS) observes the polarized cosmic microwave background (CMB) over the angular scales of 1 degrees less than or similar to theta <= 90 degrees with the aim of characterizing primordial gravitational waves and cosmic reionization. We report on the on-sky performance of the CLASS Q-band (40 GHz), W-band (90 GHz), and dichroic G-band (150/220 GHz) receivers that have been operational at the CLASS site in the Atacama desert since 2016 June, 2018 May, and 2019 September, respectively. We show that the noise-equivalent power measured by the detectors matches the expected noise model based on on-sky optical loading and lab-measured detector parameters. Using Moon, Venus, and Jupiter observations, we obtain power to antenna temperature calibrations and optical efficiencies for the telescopes. From the CMB survey data, we compute instantaneous array noise-equivalent-temperature sensitivities of 22, 19, 23, and 71 mu K-cmp root s for the 40, 90, 150, and 220 GHz frequency bands, respectively. These noise temperatures refer to white noise amplitudes, which contribute to sky maps at all angular scales. Future papers will assess additional noise sources impacting larger angular scales.
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    PHOTOMETRIC SELECTION OF A MASSIVE GALAXY CATALOG WITH z >= 0.55
    (IOP PUBLISHING LTD, 2017) Nunez, Carolina; Spergel, David N.; Ho, Shirley
    We present the development of a photometrically selected massive galaxy catalog, targeting Luminous Red Galaxies (LRGs) and massive blue galaxies at redshifts of z. >= 0.55. Massive galaxy candidates are selected using infrared/optical color-color cuts, with optical data from the. Sloan Digital Sky Survey (SDSS) and infrared data from "unWISE" forced photometry derived from the Wide-field Infrared Survey Explorer (WISE). The selection method is based on previously developed techniques to select LRGs with z > 0.5, and is optimized using receiver operating characteristic curves. The catalog contains 16,191,145 objects, selected over the full SDSS DR10 footprint. The redshift distribution of the resulting catalog is estimated using spectroscopic redshifts from the DEEP2 Galaxy Redshift Survey and photometric redshifts from COSMOS. Restframe U - B colors from DEEP2 are used to estimate LRG selection efficiency. Using DEEP2, the resulting catalog has an. average redshift of z - 0.65, with a. standard deviation of sigma = 2.0, and an. average restframe of. U - B = 1.0, with a. standard deviation of sigma = 0.27. Using COSMOS, the resulting catalog has an. average redshift of z = 0.60, with a standard deviation of sigma = 1.8. We estimate 34% of the catalog to be blue galaxies with z >= 0.55. An estimated 9.6% of selected objects are blue sources with redshift z < 0.55. Stellar contamination is estimated to be 1.8%.
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    Two Year Cosmology Large Angular Scale Surveyor (CLASS) Observations: Long Timescale Stability Achieved with a Front-end Variable-delay Polarization Modulator at 40 GHz
    (2021) Harrington, Kathleen; Datta, Rahul; Osumi, Keisuke; Ali, Aamir; Appel, John W.; Bennett, Charles L.; Brewer, Michael K.; Bustos, Ricardo; Chan, Manwei; Chuss, David T.; Cleary, Joseph; Couto, Jullianna Denes; Dahal, Sumit; Dunner, Rolando; Eimer, Joseph R.; Essinger-Hileman, Thomas; Hubmayr, Johannes; Espinoza Inostroza, Francisco Raul; Iuliano, Jeffrey; Karakla, John; Li, Yunyang; Marriage, Tobias A.; Miller, Nathan J.; Nunez, Carolina; Padilla, Ivan L.; Parker, Lucas; Petroff, Matthew A.; Pradenas Marquez, Bastian; Reeves, Rodrigo; Fluxa Rojas, Pedro; Rostem, Karwan; Valle, Deniz Augusto Nunes; Watts, Duncan J.; Weiland, Janet L.; Wollack, Edward J.; Xu, Zhilei
    The Cosmology Large Angular Scale Surveyor (CLASS) is a four-telescope array observing the largest angular scales (2 less than or similar to l less than or similar to 200) of the cosmic microwave background (CMB) polarization. These scales encode information about reionization and inflation during the early universe. The instrument stability necessary to observe these angular scales from the ground is achieved through the use of a variable-delay polarization modulator as the first optical element in each of the CLASS telescopes. Here, we develop a demodulation scheme used to extract the polarization timestreams from the CLASS data and apply this method to selected data from the first 2 yr of observations by the 40GHz CLASS telescope. These timestreams are used to measure the 1/f noise and temperature-to-polarization (T -> P) leakage present in the CLASS data. We find a median knee frequency for the pair-differenced demodulated linear polarization of 15.12 mHz and a T -> P leakage of <3.8 x 10(-4) (95% confidence) across the focal plane. We examine the sources of 1/f noise present in the data and find the component of 1/f due to atmospheric precipitable water vapor (PWV) has an amplitude of 203 +/- 12 mu K-RJ root s for 1 mm of PWV when evaluated at 10 mHz; accounting for similar to 17% of the 1/f noise in the central pixels of the focal plane. The low levels of T -> P leakage and 1/f noise achieved through the use of a front-end polarization modulator are requirements for observing of the largest angular scales of the CMB polarization by the CLASS telescopes.