Published July 1, 2008 | Version Published
Journal Article Open

SANEPIC: a mapmaking method for time stream data from large arrays

  • 1. ROR icon University of British Columbia
  • 2. ROR icon Astroparticle and Cosmology Laboratory
  • 3. ROR icon Cardiff University
  • 4. ROR icon Jet Propulsion Lab
  • 5. ROR icon California Institute of Technology
  • 6. ROR icon University of Pennsylvania
  • 7. ROR icon University of Miami
  • 8. ROR icon National Institute of Astrophysics, Optics and Electronics
  • 9. ROR icon Canadian Institute for Theoretical Astrophysics
  • 10. ROR icon University of Toronto
  • 11. ROR icon University of Puerto Rico System
  • 12. ROR icon Brown University

Abstract

We describe a mapmaking method that we have developed for the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) experiment, but which should have general application to data from other submillimeter arrays. Our method uses a maximum likelihood-based approach, with several approximations, which allows images to be constructed using large amounts of data with fairly modest computer memory and processing requirements. This new approach, Signal and Noise Estimation Procedure Including Correlations (SANEPIC), builds on several previous methods but focuses specifically on the regime where there are a large number of detectors sampling the same map of the sky, and explicitly allowing for the possibility of strong correlations between the detector time streams. We provide real and simulated examples of how well this method performs compared with more simplistic mapmakers based on filtering. We discuss two separate implementations of SANEPIC: a brute-force approach, in which the inverse pixel-pixel covariance matrix is computed, and an iterative approach, which is much more efficient for large maps. SANEPIC has been successfully used to produce maps using data from the 2005 BLAST flight.

Additional Information

© 2008 The American Astronomical Society. Received 2007 May 29; accepted 2007 November 27. The BLAST collaboration acknowledges the support of NASA through grants NAG5-12785, NAG5-13301, and NNGO-6GI11G, the Canadian Space Agency (CSA), Canada's Natural Sciences and Engineering Research Council (NSERC), and the UK Particle Physics and Astronomy Research Council (PPARC). We would also like to thank the Columbia Scientific Balloon Facility (CSBF) staff for their outstanding work. We are grateful to Matthew Hasselfield and DuncanHanson for valuable discussions that contributed to the development of SANEPIC. L. O. acknowledges partial support by the Puerto Rico Space Grant Consortium and by the Fondo Istitucional para la Investigacion of the University of Puerto Rico. C. B. N. acknowledges support from the Canadian Institute for Advanced Research. This research made use of WestGrid computing resources, which are funded in part by the Canada Foundation for Innovation, Alberta Innovation and Science, BC Advanced Education, and the participating research institutions.

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Additional details

Identifiers

Eprint ID
14245
Resolver ID
CaltechAUTHORS:20090517-205138563

Funding

NASA
NAG5-12785
NASA
NAG5-13301
NASA
NNGO-6G111G
Canadian Space Agency (CSA)
Natural Sciences and Engineering Research Council of Canada (NSERC)
Particle Physics and Astronomy Research Council (PPARC)
Puerto Rico Space Grant Consortium
University of Puerto Rico
Canadian Institute for Advanced Research (CIFAR)
Canada Foundation for Innovation
Innovation Alberta
British Columbia Ministry of Advanced Education

Dates

Created
2009-07-08
Created from EPrint's datestamp field
Updated
2021-11-08
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Physics Department