contamination

tessilator.contaminants.contamination(t_targets, ap_rad=1.0, n_cont=10, cont_rad=10.0, mag_lim=3.0, tot_attempts=3)

Estimate flux from neighbouring contaminant sources.

The purpose of this function is to estimate the amount of flux incident in the TESS aperture that originates from neighbouring, contaminating sources. Given that the passbands from TESS (T-band, 600-1000nm) are similar to Gaia RP magnitude, and that Gaia can observe targets down to G~21, the Gaia DR3 catalogue is used to quantify contamination.

For each target in the input file, the function “run_sql_query_contaminants” returns a catalogue of Gaia DR3 objects of all neighbouring sources that are within a chosen pixel radius and are brighter than $RP_{rm source}+$mag_lim.

The Rayleigh formula is used to calculate the fraction of flux incident in the aperture from the target, and the function “flux_fraction_contaminant” uses an analytical formula (Biser & Millman 1965, equation 3b-10) to calculate the flux contribution from all neighbouring sources incident in the aperture.

Parameters:

t_targetsastropy.table.Table

The input table for all the targets.

ap_radfloat, optional, default=1.0

The size of the radius aperture (in pixels)

n_contint, optional, default=10

The maximum number of neighbouring contaminants to store to table.

cont_radfloat, optional, default=10.

The maximum pixel radius to search for contaminants

mag_limfloat, optional, default=3.

The faintest magnitude to search for contaminants.

tot_attemptsint, optional, default=3

The number of sql query attempts to be made to acquire Gaia DR3 data for a contaminant before a time-out error occurs.

Returns:

t_targetsastropy.table.Table

The input table for all the targets with 3 extra columns to quantify the flux contamination.

t_contastropy.table.Table

A table of Gaia DR3 data for the contaminants.