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21 cm Cosmology Workshop

August 30, 2022 to September 2, 2022
UW Madison
America/Chicago timezone
The workshop focuses on sharing recent progress and challenges from all the major 21 cm intensity mapping efforts, both EoR and post-EoR, to help this field reach its full potential. We will discuss important common challenges: calibration, sources of local correlated signals, foreground mitigation, cross-correlations, systematics from digital signal processing, validation, and software tools.

Scientific organizing Committee

Contribution List

24 out of 24 displayed
  1. 24. Welcome to Madison!
    Peter Timbie
    8/31/22, 7:00 AM
  2. 1. X-coupling, calibration in HERA
    Nick Kern (MIT)
    8/31/22, 7:15 AM

    Instrumental systematics pose a significant threat to 21 cm telescopes aiming to detect a weak cosmological signal behind bright foreground emission. I will discuss the kinds of instrumental coupling systematics seen in HERA data and the tools we are developing to mitigate these systematics in 21 cm power spectrum analyses, including extended calibration techniques and complex visibility...

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  3. 2. Achieving Precision Calibration for 21 cm Cosmology with DWCal
    Ruby Byrne (CalText)
    8/31/22, 7:40 AM

    One of the primary challenges of 21 cm cosmology analyses is overcoming calibration error. Established calibration approaches in the field require an exquisitely accurate sky model. Even low-level sky model errors introduce calibration errors that corrupt the cosmological signal and prevent a detection. We present a novel approach called Delay-Weighted Calibration, or DWCal. DWCal enables...

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  4. 16. Validation of Software Pipelines: the HERA Experience
    James Aguirre (UPenn / HERA)
    8/31/22, 8:05 AM

    The extraction of the desired signal from 21 cm cosmology experiments faces steep challenges: the combined issues of data size, weak signal, strong foregrounds, and complex instruments couple with sophisticated, constantly-evolving, multi-step software pipelines developed by large groups to produce a situation which undermines confidence in the final analysis. The challenges of producing...

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  5. 26. Practical Foreground Removal with CHIME
    Richard Shaw (UBC)
    8/31/22, 9:00 AM
  6. 14. H I constraints from the cross-correlation of eBOSS galaxies and Green Bank Telescope intensity maps
    Laura Wolz (Manchester)
    8/31/22, 9:25 AM

    I will present the joint analysis of HI Intensity Mapping observations with three galaxy samples: the Luminous Red Galaxy (LRG) and Emission Line Galaxy (ELG) samples from the eBOSS survey, and the WiggleZ Dark Energy Survey sample. The H I intensity maps are Green Bank Telescope observations of the redshifted 21cm emission on 100deg2 covering the redshift range 0.6 < z < 1.0. I will show...

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  7. 8. 21cm Intensity Mapping: opportunities and challenges on the road to the SKA Observatory
    Marta Spinelli (ETH)
    8/31/22, 9:50 AM

    A key point for 21cm Intensity Mapping studies in the post-reionization Universe is the subtraction of the bright foregrounds,orders of magnitude stronger than the pristine cosmological signal. In this talk, I will briefly describe the status of MeerKLASS, an Intensity Mapping survey with the MeerKAT telescope. Moreover, I will report the results of an effort, led by the SKA Intensity Mapping...

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  8. 7. MeerKAT HI intensity mapping cross-correlations with overlapping galaxy surveys at z~0.4
    Steve Cunnington (Manchester/ MeerKAT)
    8/31/22, 10:15 AM

    I will present details of the first detection of cosmological signal using HI intensity mapping with a multi-dish array. For this we used the 64 dish MeerKAT telescope, a pathfinder for the Square Kilometre Array Observatory (SKAO), operating in single-dish mode, whereby the array is used as a collection of scanning auto-correlation dishes rather than as an interferometer. The detection is...

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  9. 15. Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen from LOFAR
    Florent Mertens (LOFAR)
    8/31/22, 10:40 AM

    Direct detection of the Epoch of Reionization via the redshifted 21-cm line will have unprecedented implications on the study of structure formation in the early Universe. This exciting goal is challenged by the difficulty of extracting the feeble 21-cm signal buried under bright astrophysical foregrounds and contaminated by numerous systematics. The LOFAR-EoR project has recently made...

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  10. 4. Deep learning approach for identification of HII regions and 21-cm signal recovery from SKA reionisation observations
    Michele Bianco (EPFL LASTRO)
    8/31/22, 12:45 PM

    (SKA-Low) will map the distribution of neutral hydrogen during reionisation and produce a tremendous amount of 3D tomographic data. These image cubes will be subject to instrumental limitations, such as systematic noise, foreground contamination, radio frequency interference (RFI) and limited resolution. The challenge of this astronomy image is the undesired astronomical and instrumental noise...

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  11. 13. RFI removal with Neural Networks
    Ben Saliwanchik (BNL)
    8/31/22, 1:10 PM
  12. 17. Low frequency global sky model
    George Carter (Cambridge)
    8/31/22, 1:35 PM

    Accurate modelling of the Galactic radio foreground is essential for detecting the cosmological 21cm signal. Such a model can aid foreground mitigation in both ongoing searches for the global EoR signal and upcoming efforts by instruments such as HERA to detect the 21cm brightness temperature power spectrum. In this talk, we outline a new low frequency global sky model, the Bayesian Global Sky...

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  13. 6. FAST
    Yougang Wang (NAOC)
    9/1/22, 7:00 AM
  14. 9. Tianlai Cylinder Array
    Shifan Zuo (NAOC)
    9/1/22, 7:25 AM
  15. 3. Progress Toward Constraint of the Cosmic Dawn from 21 cm Measurements with the OVRO-LWA Stage III
    Ruby Byrne (CalTech)
    9/1/22, 7:50 AM

    The highly redshifted 21 cm emission line from neutral hydrogen has the potential to reveal the temperature, density, and ionization fraction of the IGM during the Cosmic Dawn, when the first stars and galaxies illuminated the universe. The Long Wavelength Array at the Owens Valley Radio Observatory (OVRO-LWA) is currently undergoing an upgrade that substantially improves its sensitivity to...

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  16. 23. Digital Systematics
    Miguel Morales (University of Washington), Miguel Morales
    9/1/22, 8:15 AM
  17. 18. Characterization of the LWA Antenna and Station Beam Pattern
    Chris DiLullo (NASA Goddard)
    9/1/22, 9:45 AM

    I will present ongoing work to better characterize the response of the Long Wavelength Array (LWA) antenna. Recent work has focused on directly measuring the impedance mismatch between the antenna and front end electronics (FEEs). Custom calibration and testing fixtures were created which allows for measurement of the antenna impedance at the feed points on the FEE boards. These measurements...

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  18. 19. Beam calibration using holography for CHIME
    Alex Reda (Yale)
    9/1/22, 10:10 AM
  19. 22. HIRAX Electromagnetic Design
    Ben Saliwanchik (Brookhaven National Lab)
    9/1/22, 10:35 AM
  20. 21. Capturing the shape and variations of beams with holography
    Julien Girard (Observatoire de Paris)
    9/1/22, 11:00 AM

    With unprecedented sensitivity and field of view, new generation radiotelescopes at low frequencies have to face new calibration challenges. One of the main drivers to cope with direction-dependent distortion (due to strong off-axis sources) is to develop a knowledge of beamshapes and how they vary in frequency and direction. I am going to present recent modelling work carried on VLA and...

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  21. 10. Tianlai Dish Array: Beam Calibration, Correlated Noise, Ground Pickup
    Albert Stebbins (Fermilab)
    9/1/22, 1:15 PM
  22. 11. PAON4 X-correlated noise, satellites for beam, status of electronics (IDROGEN)
    Olivier Perdereau (IJCLab)
    9/1/22, 1:40 PM
  23. 25. Conference Dinner - Memorial Union, Third Floor, Old Madison Room
    9/1/22, 7:00 PM
  24. 12. HIRAX EM design sims
    Kit Gerodias (McGill)