findabsorptionfeatures: Find Absorption Features in a Spectrum
In rvmethod: Radial Velocity Method for Detecting Exoplanets

Description Usage Arguments Value Examples

This function applies the Absorption Feature Finder algorithm (Algorithm 1 in Holzer et. al 2020) to find absorption features in a high signal-to-noise, normalized, spectrum. For a spectrum that covers more than 100 Angstroms, it is recommended to parallelize it by setting the cores argument to be greater than 1.

findabsorptionfeatures(
  wvl,
  flux,
  pix_range = 7,
  gamma = 0.01,
  alpha = 0.05,
  minlinedepth = 0,
  cores = 1
)

`wvl`	vector of wavelengths in the spectrum
`flux`	vector of normalized flux in the spectrum (must have the same length as `wvl`)
`pix_range`	integer that specifies the window size in units of pixels to use in the moving linear regression
`gamma`	significance level used in finding local minima
`alpha`	significance level used in estimating wavelength bounds of features (Note: this must be larger than `gamma`)
`minlinedepth`	minimum depth required for found absorption features to be returned
`cores`	number of cores to parallelize over (if set to 1, no parallelizing is done)

a list with the following components:

`wvbounds`	a list of length 2 vectors that each give the lower and upper bounds of found absorption features
`min_wvl`	a vector of the wavelengths at which the minimum flux is achieved for each found absorption feature
`min_flx`	a vector of the minimum flux for each found absorption feature
`max_flx`	a vector of the maximum flux for each found absorption feature

data(template)
ftrs = findabsorptionfeatures(template$Wavelength,
                              template$Flux,
                              pix_range = 8, gamma = 0.05,
                              alpha = 0.07, minlinedepth = 0.015)
plot(template$Wavelength, template$Flux,
     type='l', xlab = "Wavelength", ylab = "Flux")
for(i in 1:length(ftrs$wvbounds)){
  lines(ftrs$wvbounds[[i]],
        c(1,1) - 0.01*rep(i%%2,2), col=3)
}