LoSiTo scripts

LoSiTo includes a number of convenience scripts to help with constructing simple sky models and FITS TEC screens. They are located in the bin/ directory of the LoSiTo source tree.

Sky model script

The sky model script, called skymodel, can be used to generate a variety of simple sky models for use with LoSiTo.

usage: skymodel [-h] [--output OUTPUT] [--kind KIND] [--radius RADIUS]
                [--nptsrc NPTSRC] [--ngauss NGAUSS] [--minflux MINFLUX]
                [--maxflux MAXFLUX] [--minmaj MINMAJ] [--maxmaj MAXMAJ]
                [--maxell MAXELL] [--minspidx MINSPIDX] [--maxspidx MAXSPIDX]
                [--logsi LOGSI]
                msfile

skymodel - generate simple sky models

positional arguments:
  msfile               Input MS filename.

optional arguments:
  -h, --help           show this help message and exit
  --output OUTPUT      Ouput sky model filename.
  --kind KIND          Kind of sky model: cross, spiral, tree, cat or random.
  --radius RADIUS      Radius in degrees within which sources are added.
  --nptsrc NPTSRC      Number of point sources to generate.
  --ngauss NGAUSS      Number of Gaussians to generate (kind=random only).
  --minflux MINFLUX    Minimum peak flux density in Jy (kind=random only).
  --maxflux MAXFLUX    Maximum peak flux density in Jy (kind=random only).
  --minmaj MINMAJ      Minimum major axis in arcsec of Gaussian sources.
  --maxmaj MAXMAJ      Maximum major axis in arcsec of Gaussian sources.
  --maxell MAXELL      Maximum ellipticity (1 - maj/min) of Gaussian sources.
  --minspidx MINSPIDX  Minimum spectral index of sources (kind=random only).
  --maxspidx MAXSPIDX  Maximum spectral index of sources (kind=random only).
  --logsi LOGSI        Value for LogarithmicSI: true or false (kind=random
                       only).

Synthms script

The synthms script can be used to create artificial LOFAR measurement sets from scratch. Freely choose the spectral windows, source direction and observation time. You also can select whether to simulate an LBA or HBA observation.

The sub-bands both for LBA and HBA start at SB150, the highest sub-band is SB393.

The script also features the generation of LOFAR2.0 simultaneous LBA + HBA measurements. In this case, the full 96 LBA of all stations will be used.

usage: synthms [-h] [--name NAME] [--start START] [--tobs TOBS]
                [--ra RA] [--dec DEC] [--station STATION]
                [--lofarversion LOFARVERSION] [--minsb MINSB] [--maxsb MAXSB]

synthms - synthesize input ms files


optional arguments:
  -h, --help           show this help message and exit
  --name NAME          MS file prefix
  --start START        Start of the obervation in MJD seconds.
  --tobs TOBS          Observation time in hours.
  --ra RA              Target right ascension in rad
  --dec DEC            Target declination in rad
  --station            >LBA<, >HBA< or >both<
  --lofarversion LOFARVERSION   >1< for the current instrument, >2< for LOFAR2.0
  --minsb MINSB        Specify the lowest sub band of the observation. The lowest possible subband is defined as SB150
  --maxsb MAXSB        Highest sub band

TEC screen script

This script is currently not maintained, you might want to use another TEC-method, see :ref:`tec` The TEC screen script, called tecscreen, can be used to generate a TEC screen FITS cube for use with LoSiTo (and WSClean). The output FITS cube conforms to format accepted by WSClean (see https://sourceforge.net/p/wsclean/wiki/ImageDomainGridder/#tec-correction).

Note

Other TEC screens can be generated directly (as h5parm tables instead of FITS cubes) in the TEC operation.

usage: tecscreen [-h] [--polygrade POLYGRADE] [--npixels NPIXELS]
                 [--size SIZE] [--seed SEED] [--maxdtec MAXDTEC] [--freq FREQ]
                 msfile fitsfile

tecscreen - generate simple TEC screen FITS files

positional arguments:
  msfile                Input MS filename
  fitsfile              Output FITS filename

optional arguments:
  -h, --help            show this help message and exit
  --polygrade POLYGRADE
                        define grade of polynomial
  --npixels NPIXELS     number of screen pixels
  --size SIZE           width of screen in degrees
  --seed SEED           define random seed
  --maxdtec MAXDTEC     maximum dTEC value in screen
  --freq FREQ           factor controlling frequency