contamination

tessilator.contaminants.contamination(t_targets, LC_con, Rad=1.0, n_cont=5)

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 G magnitude, and that Gaia is sensitive to G~21, the Gaia DR3 catalogue is used to quantify contamination.

For each target in the input file, the function “runSQLQueryContaminants” returns a catalogue of Gaia DR3 objects of all neighbouring sources that are within a chosen pixel radius and are brighter than $G_{source} + 3$.

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.

LC_conbool

If true, a table of Gaia DR3 information on the contaminants is returned, else None.

Radfloat, optional, default=1.0

The size of the radius aperture (in pixels)

n_contint, optional, default=5

The maximum number of neighbouring contaminants to store to table if LC_con is True.

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 or None

If LC_con is true, a table of Gaia DR3 information on the contaminants is returned, else None.