Miscellaneous¶

Commands that don't fit cleanly into any of the other command categories.

`-findblends`¶

Syntax

-findblends
    matchrad ["radec"] ["xycol" xcol ycol]
    < "fix" period | "list" ["column" col] | "fixcolumn" <colname | colnum> >
    ["starlist" starlistfile] ["zeromag" zeromagval] ["nofluxconvert"]
    ["Nharm" Nharm] ["omatches" outputmatchfile]

Description

Determine whether a detected periodic signal is likely due to contamination (blending) from a nearby variable star. For each potential variable, the routine measures the flux amplitude of all nearby light curves and reports the one with the highest amplitude. A light-curve list (-l) is required with x and y coordinates as additional columns.

Python equivalent: findblends.

Parameters

Parameter	Description
`matchrad`	Matching radius (arcseconds if `"radec"`, pixels otherwise).
`"radec"`	Treat the x/y columns as RA and Dec in degrees; `matchrad` is then arcseconds.
`"xycol" xcol ycol`	Columns in the input list for x and y (default: next two available).
Period source	One of `"fix" period`, `"list" ["column" col]`, or `"fixcolumn" <col>`.
`"starlist" starlistfile`	Match against an external catalogue instead of the input list. Format: `lcname x y`.
`"zeromag" zeromagval`	Zero-point magnitude for the mag→flux conversion (default 25.0).
`"nofluxconvert"`	Skip the magnitude-to-flux conversion (input already in flux units).
`"Nharm" Nharm`	Harmonics for the Fourier amplitude measurement (default 2; 0 = sinusoid).
`"omatches" outputmatchfile`	Write per-target lists of matching stars and their flux amplitudes to this file.

Output columns: Findblends_VarName_N (name of the brightest blended variable in flux), Findblends_FluxAmp_N (its flux amplitude).

Examples

Example 1. The list EXAMPLES/lc_list_testblend contains two LCs along with their x/y coordinates. We search both for a sinusoidal signal with -LS and then check for blending — any stars within 2 pixels of each other are potential blends, and the period from -LS is used for the amplitude measurement (read from the output column with fixcolumn). Running this gives EXAMPLES/2 as the source of the variability for both LCs since it has the higher flux amplitude.

vartools -l EXAMPLES/lc_list_testblend -header \
    -LS 0.1 10. 0.1 1 0 \
    -findblends 2.0 fixcolumn LS_Period_1_0

Miscellaneous¶

-findblends¶

`-findblends`¶