Output Data Products
QA Metrics Summary
The QA metrics summary is a text file that contains the computed QA metrics for the input FITS image. Each metric is listed on a separate line, along with its value. The metrics included in the summary are:
Systematic flux density ratio offset
Robust standard deviation of flux density ratio
Median total-to-peak flux density ratio
Systematic positional offset (arcsec)
Robust standard deviation of positional offset (arcsec)
Diagnostic plots
The diagnostic plot is a PNG image that provides a visual summary of the QA metrics. It includes plots of the flux density ratios and positional offsets of the detected sources compared to the reference sky model, as well as a histogram of the total-to-peak flux density ratios.
A sample plot is shown below:
Matched Catalogue
The matched catalogue is a CSV file containing the sources that were successfully matched between the sources detected by the source finder in the input FITS image and the reference sky model. Each row corresponds to a matched source pair and the columns include the properties of the reference and detected sources.
The columns in the matched catalogue include (for both reference and detected sources):
Column Name |
Description |
|---|---|
ra |
Right Ascension of the source (in degrees) |
dec |
Declination of the source (in degrees) |
i |
Integrated flux density of the source (in Jy) |
peak_flux |
Peak flux density of the source (in Jy) |
q |
Stokes Q parameter of the source (in Jy) |
u |
Stokes U parameter of the source (in Jy) |
v |
Stokes V parameter of the source (in Jy) |
reference_frequency |
Reference frequency of the source (in Hz) |
spectral_index |
Spectral index of the source |
rotation_measure |
Rotation measure of the source (in rad/m^2) |
major_axis |
Major axis of the source (in arcsec) |
minor_axis |
Minor axis of the source (in arcsec) |
position_angle |
Position angle of the source (in degrees) |
e_ra |
Uncertainty in Right Ascension (in arcsec) |
e_dec |
Uncertainty in Declination (in arcsec) |
e_i |
Uncertainty in integrated flux density (in Jy) |
e_peak_flux |
Uncertainty in peak flux density (in Jy) |
e_q |
Uncertainty in Stokes Q parameter (in Jy) |
e_u |
Uncertainty in Stokes U parameter (in Jy) |
e_v |
Uncertainty in Stokes V parameter (in Jy) |
e_spectral_index |
Uncertainty in spectral index |
e_rotation_measure |
Uncertainty in rotation measure (in rad/m^2) |
e_major_axis |
Uncertainty in major axis (in arcsec) |
e_minor_axis |
Uncertainty in minor axis (in arcsec) |
e_position_angle |
Uncertainty in position angle (in degrees) |
Additionally, the catalogue includes the following columns that describe the matching between the reference and detected sources:
Column Name |
Description |
|---|---|
match_id |
A unique identifier for the matched source pair |
separation_arcsec |
Angular separation between the reference and detected source (in arcsec) |
Intermediate Products (Numerical Arrays)
The intermediate numerical arrays are saved as NumPy binary files (with .npy extension) and contain the following data:
File |
Description |
|---|---|
flux_density_ratios.npy |
An array of the flux density ratios (detected flux density divided by reference flux density) for the matched sources |
positional_offsets.npy |
An array of the positional offsets (angular separation in arcseconds between the detected and reference sources) for the matched sources |