31 August 2022 to 2 September 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.

To advance progress in the practice of 21 cm intensity mapping we are organizing a community workshop on 21 cm cosmology instrumentation in Madison Wisconsin on August 31 through September 2, 2022 (Wed-Fri).  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. 

Wednesday Aug 31 2022  & Thursday Sept 1 2022 

Morning sessions : plenary presentations, Afternoon : working groups 

Friday morning Sept 2 2022 : report from working groups and workshop summary  

Preliminary program :

     Calibration : 
    1.   X-coupling and calibration in HERA  ( Nick Kern ) 
    2.   Achieving Precision Calibration for 21 cm Cosmology with DWCal (Ruby Byrne )    
  1.   Beams & EM simulations 
    1.  HIRAX EM design  ( Ben Saliwanchik ) 
    2.  Characterization of the LWA Antenna and Station Beam Pattern (Chris Di Lullo)
    3. Beam calibration using holography for CHIME (Alex Reda )  
    4. Capturing the shape and variations of beams with holography (Julien Girard) 
  2. 21cm & EoR 
    1. Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen from LOFAR ( Florent Mertens )  
    2. Progress Toward Constraint of the Cosmic Dawn from 21 cm Measurements with the OVRO-LWA Stage III ( Ruby Byrne )
  3.   Correlated Noise , Ground pickup, Digital systems 
    1. Tianlai dish beam calibration, correlated noise, ground pickup ( Albert Stebbins )  
    2. PAON4 X-correlated noise, satellites for beam, status of electronics (IDROGEN) (O. Perdereau )
    3. Digital systematics (Miguel Morales) 
      Foregrounds , Sky Model 
    1.   Low frequency global sky model ( George Carter ) 
    2.   HERA software validation (James Aguirre) 
    3.   Tianlai cylinder data processing (Shifan Zuo ) 
  4.   Cross-Correlations 
    1.   GBT data & optical surveys cross correlations ( Laura Wolz ) 
    2.   MeerKAT HI intensity mapping cross-correlations with overlapping galaxy surveys at z~0.4 ( Steve Cunnington ) 
  5.   Intensity mapping with single dishes
    1. Intensity Mapping with FAST ( Yougang Wang )  
    2. 21cm Intensity Mapping: opportunities and challenges on the road to the SKA Observatory ( M. Spinelli )
  6.   Application of machine learning and AI 
    1. RFI removal using neural network ( Ben Saliwanchick ) 
    2. Deep learning approach for identification of HII regions and 21-cm signal recovery from SKA reionisation observations (Michele Bianco)

Workshop topics:

Beam and gain calibration

  • the practice of calibration from the sky, redundant baselines and their combination
  • use of drones, holography and EM simulation
  • pass band structures
  • Sources of correlated signals (other than sky)
    • cross talk, feed cross coupling, ground pickup
  • Advances in mitigation of foregrounds
    • foreground wedge and its leakage in practice
    • identifying the 21 cm signal in the presence of foregrounds
  • Cross-correlations as a tool:
    • for identifying systematics
    • for validation
  • Systematics associated with digital signal processing
  • Validation- building confidence in the reality of an extracted 21 cm   signal;  use of independent simulations and analysis pipelines; blind analysis
  •  Software tools

The detailed schedule of talks will appear during the week of August 1.  Of course, not all of these topics can be fully covered in a few day workshop but we hope to make progress in some of these areas according to who is in attendance.   Expect to have frank discussions of issues encountered and solutions found or under development by practitioners of 21 cm hydrogen intensity mapping.

This will be a hybrid meeting.  The morning session will be broadcast over Zoom and consist mainly of scheduled talks.  The afternoon sessions will be less structured.  A synopsis of the afternoon sessions will be presented during the Friday morning broadcasts.  In-person talks will take precedence over virtual talks as this allows for more followup discussion, but participants are welcome to attend in-person or remotely.

We plan to divide up the task of writing a Workshop Summary.  We think this will be a useful planning document for the community and plan to post it on the arXiv.

We are sending this open invitation to all groups currently working in this field with the hope that they will identify their members best able to contribute to and benefit from such discussions; and encourage them to attend.  Feel free to pass this on to interested parties and to suggest topics which we have missed.  Those interested in contributing a talk should contact the SoC at soc21cm@lists.physics.wisc.edu along with a proposal for the presentation.  (The number of talks is limited due to time limitations.  For full consideration for a formal presentation please contact us by July 20, 2022.)  We also welcome attendance by those not planning to give a talk.  A registration page for all workshop attendees is on this website.

Unfortunately, we are unable to assist in funding travel expenses.  However, a block of rooms will be reserved at a discounted rate at the University of Wisconsin which operates a number of hotels.

There will be a modest registration fee for those attending in-person to pay for meals and refreshments.

We look forward to a fruitful workshop and to seeing some of you, in person or virtually.

The Scientific Organizing Committee

Reza Ansari
Xuelei Chen
Danny Jacobs
Miguel Morales
Laura Newburgh
Albert Stebbins
Peter Timbie

This workshop is hosted by the University of Wisconsin and the Tianlai collaboration. It will be preceded by the annual Tianlai collaboration meeting on August 29-30, (Mon-Tues), which is open to all.  Contact Peter Timbie (pttimbie@wisc.edu) if you would like to attend the collaboration meeting.

panoramic of Madison isthmus

UW Madison
B343 Sterling Hall
475 North Charter Street Madison, WI 53706
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