SC/19.3

Starlink Project
Starlink Cookbook 19.3

Edward Chapin, Jessica Dempsey, Tim Jenness, Douglas Scott, Holly Thomas & Remo Tilanus

3 August 2010

Copyright © 2009-2010 University of British Columbia
Copyright © 2009-2010 Science & Technology Facilities Council

The SCUBA-2 SRO Data Reduction Cookbook

1.1

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Abstract

This cookbook provides a short introduction to Starlink facilities, especially Smurf, the Sub-Millimetre User Reduction Facility, for reducing and displaying SCUBA-2 SRO data. We describe some of the data artefacts present in SCUBA-2 time series and methods we employ to mitigate them. In particular, we illustrate the various steps required to reduce the data, and the Dynamic Iterative Map-Maker, which carries out all of these steps using a single command.

For information on SCUBA-2 data reduction since SRO, please see SC/21.

Contents

1 Introduction
2 SCUBA-2 Data Files
3 Visualising data
 3.1 Concatenating data
 3.2 Displaying scan patterns
 3.3 Displaying data cubes
 3.4 Regridding data into a map
 3.5 Cleaning data
  3.5.1 Removing bolometer averages and DC Steps
  3.5.2 Watching a movie
  3.5.3 Frequency-domain filtering
 3.6 Bolometer power-spectra
 3.7 Data quality flagging
4 Dynamic Iterative Map-Making
 4.1 Configuration Files
5 Calibrating SCUBA-2 Data
 5.1 Extinction Correction
 5.2 Flux conversion factors
6 Examples of different reductions
 6.1 Deep point source maps
 6.2 Extended Galactic Sources
  6.2.1 Standard DIMM configuration + Picard
  6.2.2 Bright / extended DIMM configuration
7 Cheat sheet for checking data quality
 7.1 Using sc2clean to help inspect time-series
 7.2 Looking at calibration data
References
A Data Characteristics and Issues
 A.1 Introduction data issues
 A.2 Telescope tracking
 A.3 Flat field
 A.4 Spikes and Steps
 A.5 Common Mode Signal
  A.5.1 Method 1
  A.5.2 Method 2
 A.6 Maps
 A.7 Sample Common-mode script
B Notes on Shared Risk Observing
 B.1 S2SRO FCFs
 B.2 Method for calibrating your data
 B.3 Significant Events
  B.3.1 Data Files
  B.3.2 Flatfields
  B.3.3 Setup
  B.3.4 Electronics
  B.3.5 Weather
  B.3.6 Telescope
C List of acronyms

References

[1]   Chapin E. L., et al., 2009, SMURF – Sub-Millimetre User Reduction Facility, Starlink User Note 258

[2]   Currie M. J., Wallace P. T., Warren-Smith R. F., 1989, Starlink Standard Data Structures, Starlink General Paper 38.2

[3]   Currie M. J., 1997, KAPPA — Kernel Application Package, Starlink User Note 95

[4]   Draper P. W., 1997, GAIA – Graphical Astronomy and Image Analysis Tool, Starlink User Note 214

[5]   Scott D., Van Engelen A., 2005, Scan Mode Strategies for SCUBA-2, SCUBA-2 Data Reduction document SC2/ANA/S210/005

[6]   Dempsey J. T., Friberg P., Jenness T., Bintley D., Holland W. S., 2010 Extinction correction and on-sky calibration of SCUBA-2, Proc. SPIE, 7741 (DOI:10.1117/12.856476)

[7]   Archibald, E. N., et al, 2002, On the atmospheric limitations of ground-based submillimetre astronomy using array receivers, MNRAS, 336, 1-13

[8]   Jenness T., et al, 2002, Towards the automated reduction and calibration of SCUBA data from the James Clerk Maxwell Telescope, MNRAS, 336, 14-21

[9]   Barnard, V. E., 2005,A summary of the search for new Submillimetre Secondary Calibrators, Tech. Rep. SCD/SN/011, Joint Astronomy Centre