CaltechAUTHORS: Combined
https://feeds.library.caltech.edu/people/Padin-Stephen/combined.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 08 Oct 2024 19:22:29 -0700Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck. I. Construction of CMB lensing maps and modeling choices
https://authors.library.caltech.edu/records/j1h81-h9g43
Year: 2023
DOI: 10.1103/physrevd.107.023529
<p>Joint analyses of cross-correlations between measurements of galaxy positions, galaxy lensing, and lensing of the cosmic microwave background (CMB) offer powerful constraints on the large-scale structure of the Universe. In a forthcoming analysis, we will present cosmological constraints from the analysis of such cross-correlations measured using Year 3 data from the Dark Energy Survey (DES), and CMB data from the South Pole Telescope (SPT) and <em>Planck</em>. Here we present two key ingredients of this analysis: (1) an improved CMB lensing map in the SPT-SZ survey footprint and (2) the analysis methodology that will be used to extract cosmological information from the cross-correlation measurements. Relative to previous lensing maps made from the same CMB observations, we have implemented techniques to remove contamination from the thermal Sunyaev Zel’dovich effect, enabling the extraction of cosmological information from smaller angular scales of the cross-correlation measurements than in previous analyses with DES Year 1 data. We describe our model for the cross-correlations between these maps and DES data, and validate our modeling choices to demonstrate the robustness of our analysis. We then forecast the expected cosmological constraints from the galaxy survey-CMB lensing auto and cross-correlations. We find that the galaxy-CMB lensing and galaxy shear-CMB lensing correlations will on their own provide a constraint on 𝑆8=𝜎8√Ωm/0.3 at the few percent level, providing a powerful consistency check for the DES-only constraints. We explore scenarios where external priors on shear calibration are removed, finding that the joint analysis of CMB lensing cross-correlations can provide constraints on the shear calibration amplitude at the 5% to 10% level.</p>https://authors.library.caltech.edu/records/j1h81-h9g43Cryogenic focus measurement system for a wide-field infrared space telescope
https://authors.library.caltech.edu/records/phyqb-ba930
Year: 2024
DOI: 10.1364/ao.514784
<p>We describe a technique for measuring focus errors in a cryogenic, wide-field, near-infrared space telescope. The measurements are made with a collimator looking through a large vacuum window, with a reflective cold filter to reduce the background thermal infrared loading on the detectors and optics. The vacuum window and cold filter introduce a wavefront error that we characterize using an autocollimating microscope. For the 200 mm diameter aperture f/3 space telescope SPHEREx, we achieve a focus position measurement with a ∼15µm systematic and a ∼5µm statistical error.</p>https://authors.library.caltech.edu/records/phyqb-ba930Mass calibration of DES Year-3 clusters via SPT-3G CMB cluster lensing
https://authors.library.caltech.edu/records/r2h5j-9t632
Year: 2024
DOI: 10.1088/1475-7516/2024/07/024
<div class="article-text wd-jnl-art-abstract cf">
<p>We measure the stacked lensing signal in the direction of galaxy clusters in the Dark Energy Survey Year 3 (DES Y3) redMaPPer sample, using cosmic microwave background (CMB) temperature data from SPT-3G, the third-generation CMB camera on the South Pole Telescope (SPT). Here, we estimate the lensing signal using temperature maps constructed from the initial 2 years of data from the SPT-3G 'Main' survey, covering 1500 deg<sup>2</sup> of the Southern sky. We then use this lensing signal as a proxy for the mean cluster mass of the DES sample. The thermal Sunyaev-Zel'dovich (tSZ) signal, which can contaminate the lensing signal if not addressed, is isolated and removed from the data before obtaining the mass measurement. In this work, we employ three versions of the redMaPPer catalogue: a Flux-Limited sample containing 8865 clusters, a Volume-Limited sample with 5391 clusters, and a Volume&Redshift-Limited sample with 4450 clusters. For the three samples, we detect the CMB lensing signal at a significance of 12.4<em>σ</em>, 10.5<em>σ</em> and 10.2<em>σ</em> and find the mean cluster masses to be <em>M</em><sub>200m</sub> = 1.66±0.13 [stat.]± 0.03 [sys.], 1.97±0.18 [stat.]± 0.05 [sys.], and 2.11±0.20 [stat.]± 0.05 [sys.]<strong>×</strong>10<sup>14</sup> M<sub>⊙</sub>, respectively. This is a factor of ∼ 2 improvement relative to the precision of measurements with previous generations of SPT surveys and the most constraining cluster mass measurements using CMB cluster lensing to date. Overall, we find no significant tensions between our results and masses given by redMaPPer mass-richness scaling relations of previous works, which were calibrated using CMB cluster lensing, optical weak lensing, and velocity dispersion measurements from various combinations of DES, SDSS and Planck data. We then divide our sample into 3 redshift and 3 richness bins, finding no significant discrepancies with optical weak-lensing calibrated masses in these bins. We forecast a 5.7% constraint on the mean cluster mass of the DES Y3 sample with the complete SPT-3G surveys when using both temperature and polarization data and including an additional ∼ 1400 deg<sup>2</sup> of observations from the 'Extended' SPT-3G survey.</p>
</div>https://authors.library.caltech.edu/records/r2h5j-9t632