UChicago-2020: JuniorScientistTalks
Junior Scientist Talks Organized by the CMB-S4 Junior Scientist Advancement Committee
These talks are highlighting the recent work of graduate students and postdocs in cosmology.
Connection Details
Zoom: https://fnal.zoom.us/j/97391022720?pwd=QTE4ZzBzcml4MmlZQ1crWjZib0R1dz09 One-tap: +13126266799,,97391022720#,,,,,,0#,,695564# US (Chicago)
Time/Date: 8:00am - 12:15pm Pacific Time / Friday August 14, 2020
Organizers: Darcy Barron for the CMB-S4 Junior Scientist Advancement Committee
Agenda
Session 1: 8:00am - 10:15am PDT
- Yuto Minami - Simultaneous determination of the cosmic birefringence and miscalibrated polarization angles
- Dongwon 'DW' Han - The Atacama Cosmology Telescope: Delensed Power Spectra and Parameters
- Suvodip Mukherjee - Peering into patchy reionization using kSZ and B-mode polarization
- Omar Darwish - ACTPol lensing maps and foreground-cleaned galaxy correlations
- Heather McCarrick - The Simons Observatory uMux detector modules
- Benjamin Beringue - Cosmology with Rayleigh scattering
- Max Abitbol - Robust B-mode analysis for ground-based experiments
- Jahmour J. Givans - Lyman-alpha forest perturbative modeling and improved CMB constraining power
- Lindsay Ng Lowry - Development and Characterization of the POLARBEAR-2b Receiver for the Simons Array
- Shouvik Roy Choudhury - Neutrino Mass and Mass Hierarchy from Cosmology
- Marcel Schmittfull - Future cosmology with CMB lensing and galaxy clustering
- Ruby Byrne - Enabling Precision EoR Calibration
BREAK 10:15am - 10:30am PDT
Session 2: 10:30am - 12:15pm
- Anna Ho - The Landscape of Relativistic Stellar Explosions
- Charles Hill - A cryogenic half-wave plate for POLARBEAR-2b
- Tucker Elleflot - Characterization of Multiplexed Transition Edge Sensor Bolometers for the POLARBEAR-2 Cosmic Microwave Background Experiment
- Zachary Martinot - Interferometric Visibililty Simulations for HERA Data Analysis
- Kirit Karkare - Cosmology with Next-Generation Millimeter-Wave Spectrometers
- Theodore Macioce - Realistic Mock kSZ Observations to Forecast Constraints on Structure Formation and Cosmic Acceleration
- John Groh - Development and deployment of the Simons Array CMB polarization experiment
- Tyler St Germaine - Beam Systematics in BICEP3 and the Keck Array CMB Polarimeters
- Tashalee Billings - Extracting Optical Depth from Simulated 21cm Data
Speaker Information (in order of talks)
Name | Short Bio | Talk Title | Abstract |
Yuto Minami | I'm postdoc fellow of High Energy Accelerator Research Organization (KEK) in Japan. I'm members of LiteBIRD and Simons Array. My research history is here: https://inspirehep.net/authors/1238534. | Simultaneous determination of the cosmic birefringence and miscalibrated polarization angles | We show that the cosmic birefringence and miscalibrated polarization angles can be determined simultaneously by cosmic microwave background (CMB) experiments using the cross-correlation between E- and B-mode polarization data. This is possible because the polarization angles of the CMB are rotated by both the cosmic birefringence and miscalibration effects, whereas those of the Galactic foreground emission are rotated only by the latter. Our method does not require prior knowledge of the E- and B-mode power spectra of the foreground emission, but uses only the knowledge of the CMB polarization spectra. Specifically, we relate the observed EB correlation to the difference between the observed E- and B-mode spectra in the sky, and use different multipole dependences of the CMB (given by theory) and foreground spectra (given by data) to derive the likelihood for the miscalibration angle α and the birefringence angle β. We show that a future satellite mission similar to LiteBIRD can determine β with a precision of 6 arcmin. |
Dongwon 'DW' Han | A PhD student at Stony Brook University studying CMB data analysis with Dr. Neelima Sehgal | The Atacama Cosmology Telescope: Delensed Power Spectra and Parameters | "We present LCDM cosmological parameter constraints obtained from delensed microwave background power spectra. Lensing maps from a subset of DR4 data from the Atacama Cosmology Telescope (ACT) are used to undo the lensing effect in ACT spectra observed at 150 and 98 GHz. At 150 GHz, we remove the lensing
distortion with an effective efficiency of 30% (TT), 30% (EE), 26% (TE) and 20% (BB); this results in detections of the delensing effect at 8.7 sigma (TT), 5.1 sigma (EE), 2.6 sigma (TE), and 2.4 sigma (BB) significance. The combination of 150 and 98 GHz TT, EE, and TE delensed spectra is well fit by a standard LCDM model. We also measure the shift in best-fit parameters when fitting delensed versus lensed spectra; while this shift does not inform our ability to measure cosmological parameters, it does provide a three-way consistency check among the lensing inferred from the best-fit parameters, the lensing in the CMB power spectrum, and the reconstructed lensing map. This shift is predicted to be zero when fitting with the correct model since both lensed and delensed spectra originate from the same region of sky. Fitting with a LCDM model and marginalizing over foregrounds, we find that the shift in cosmological parameters is consistent with zero. Our results show that gravitational lensing of the microwave background is internally consistent within the framework of the standard cosmological model." |
Suvodip Mukherjee | University of Amsterdam, GRAPPA postdoctoral fellow, https://staff.fnwi.uva.nl/s.mukherjee/ | Peering into patchy reionization using kSZ and B-mode polarization | The epoch of cosmic reionization can be probed using the secondary anisotropies induced in the cosmic microwave background (CMB) temperature and polarization field. I will discuss the impact of patchy reionization on CMB temperature and polarization anisotropies using the results obtained from semi-numerical simulations. I will introduce two new scaling relations to connect the kSZ power spectrum and secondary B-mode power spectrum with the scenarios of patchy reionization and is going to discuss its utility for the ongoing/upcoming CMB experiments. By using a physically motivated model of reionization, I will show the first constraints on patchiness during reionization from the current kSZ measurement and will present the corresponding upper bound on the amplitude of secondary B-mode polarization. I will also discuss the advantage of a joint study of the kSZ signal and secondary B-mode polarization from the upcoming CMB experiments to unveil the reionization history. |
Omar Darwish | University of Cambridge, Blake Sherwin, PhD, CMB Lensing cross correlations, LSS reconstruction, https://www.maths.cam.ac.uk/person/od261 | ACTPol lensing maps and foreground-cleaned galaxy correlations | We construct cosmic microwave background lensing mass maps using data from the 2014 and 2015 seasons of observations with the Atacama Cosmology Telescope (ACT). These maps cover 2100 square degrees of sky and overlap with a wide variety of optical surveys. The maps are signal dominated on large scales and have fidelity such that their correlation with the cosmic infrared background is clearly visible by eye. We also create lensing maps with thermal Sunyaev-Zel’dovich contamination removed using a novel cleaning procedure that only slightly degrades the lensing signal-to-noise ratio. The cross-spectrum between the cleaned lensing map and the BOSS CMASS galaxy sample is detected at 10-σ significance, with an amplitude of A = 1.02±0.10 relative to the Planck best-fit LCDM cosmological model with fiducial linear galaxy bias. Our measurement lays the foundation for lensing cross-correlation science with current ACT data and beyond. |
Heather McCarrick | I am a postdoc at Princeton, advised by Suzanne Staggs. I primarily work on the Simons Observatory with a focus on the readout, detectors, and focal plane module design. | The Simons Observatory uMux detector modules | The Simons Observatory (SO) will be a cosmic microwave background (CMB) survey experiment with four small-aperture telescopes and one large-aperture telescope, which will observe from the Atacama Desert. In total, SO will field over 60,000 transition-edge sensor (TES) bolometers in six spectral bands centered between 27 and 280 GHz in order to achieve the sensitivity necessary to measure or constrain numerous cosmological quantities, as outlined in The Simons Observatory Collaboration et al. (2019). SO will use a microwave SQUID multiplexing (uMux) readout with an initial multiplexing factor of 1000. Comparatively, current CMB experiments use a multiplexing factor of ~64. The focal plane modules contain the uMUX readout, TES bias circuitry and detectors. The focal plane module design is both critical to the readout performance and allows for close-packing of the modules within the focal plane. In this talk, I will discuss the evolved SO focal plane module design and status. |
Benjamin Beringue | My name is Benjamin Beringue, I am a third year PhD student at the University of Cambridge under the supervision of Dr Daan Meerburg. I have been working on several aspects of CMB data analysis from forecasting detectability of Rayleigh scattering of the CMB to implementing component separation methods for SO. | Cosmology with Rayleigh scattering | "The cosmic microwave background (CMB) has been a treasure trove for cosmology. Over the next decade, current and planned CMB experiments are expected to exhaust nearly all primary CMB information. However, CMB photons can be affected after recombination, which can be a nuisance in extracting the primary modes, but will also provide valuable cosmological information. Well-studied examples include deflection of CMB photons by gravitational lensing and the Sunyaev-Zel'dovich effects describing scattering by free electrons in collapsed objects. Several of these effects have been detected and have been, or will be, used for cosmological inference.
Among these secondaries, Rayleigh scattering of the CMB is a less studied yet potentially powerful probe of the recombination history. Scattering of CMB photons off neutral species right after recombination presents a distinctive $\nu^4$ scaling with frequency as well as a strong correlation with the primary CMB. These unique features should guarantee its detection by the next generation of CMB experiments. We will present detectability forecasts combining the Simons Observatory and CCAT-prime telescopes as well as more futuristic space missions. Finally, we will present potential cosmological implications of the detection of this signal by studying improvement of parameter constrains." |