Flux density models of radio calibrators (pwkit.radio_cal_models)

pwkit.radio_cal_models - models of radio calibrator flux densities.

From the command line:

python -m pwkit.radio_cal_models [-f] <source> <freq[mhz]>
python -m pwkit.radio_cal_models [-f] CasA     <freq[mhz]> <year>

Print the flux density of the specified calibrator at the specified frequency, in Janskys.

Arguments:

<source>

the source name (e.g., 3c348)

<freq>

the observing frequency in MHz (e.g., 1420)

<year>

is the decimal year of the observation (e.g., 2007.8). Only needed if <source> is CasA.

-f

activates “flux” mode, where a three-item string is printed that can be passed to MIRIAD tasks that accept a model flux and spectral index argument.

pwkit.radio_cal_models.cas_a(freq_mhz, year)[source]

Return the flux of Cas A given a frequency and the year of observation. Based on the formula given in Baars et al., 1977.

Parameters:

freq - Observation frequency in MHz. year - Year of observation. May be floating-point.

Returns: s, flux in Jy.

pwkit.radio_cal_models.init_cas_a(year)[source]

Insert an entry for Cas A into the table of models. Need to specify the year of the observations to account for the time variation of Cas A’s emission.