Process data for the SONS project


This is the recipe for processing data taken for the SCUBA-2 Survey of Nearby Stars (SONS).

This recipe processes SCAN data, making a map from files that meet a given noise criterion, and uses a jack-knife method to remove residual low-spatial frequency noise and create an optimal matched-filtered output map. The recipe proceeds as follows:

The outcome (the match-filtered whitened signal map) should be the optimal map with white noise properties. This is the map to be used for science goals.

This recipe generates a large number of output files. There will be two for each observation (the signal map and the effective PSF map), a total signal coadd, an effective PSF coadded from all the individual effective PSF maps, a jackknife map, a whitened signal map, a calibrated whitened signal map, a matched-filtered calibrated whitened signal map and a signal-to-noise ratio map created from it.


Available Parameters :

The following parameters can be set via the -recpars option:
A flag to scale the gaussian in amplitude by the square-root of the number of maps to be created by the recipe so that the signal-to-noise ratio of the final map-filtered PSF is independent of the number of observations. Default is 1.
FWHM (in arcsec) of a gaussian to add to the timeseries. Default is to use the appropriate telescope main beam FWHM.
The offsets (in arcsec) to apply to the fake source added to the timeseries. If one value is given, it will be used for both axes. Default is to apply no shift.
Amplitude of the fake source (in Jy/beam) added to the timeseries to assess the map-making response to a point source. Default is 10/50 Jy/beam at 850/450 um respectively.
Name of a config file for use with the SMURF makemap task. The file must exist in the current working directory, $MAKEMAP_CONFIG_DIR, $ORAC_DATA_OUT, $ORAC_DATA_CAL or $STARLINK_DIR/share/smurf.
Pixel size in arcsec for the output map. Default is wavelength dependent (4 arcsec at 850 um, 2 arcsec at 450 um). Note that the timeseries will be downsampled to match this scale during the map-making process.
Size of square region (in pixels) use to define effective PSF.
Estimator for calculating the noise properties of each subscan. Supported values are WTNEP (not for METHOD=MAP), MEAN, MEDIAN and SIGMA (METHOD=MAP only). Default is SIGMA (or MEDIAN if METHOD is not MAP).
Method for determining the noise properties. Supported values are FREQHI, FREQLO and MAP. Default is MAP.
Size of the region used to calculate the angular power spectrum for removing residual low-frequency noise in the data. Default is a square region bounded by the noise being less than twice the minimum value.