spectropath

Low-order path coordinates for spectral-line profiles. Build a path from an ordered coordinate and a measured signal; spectropath returns the notation used in the paper directly.

Rafael S. de Souza · companion package for the path-signature line morphology paper

Python Functions GitHub

Minimal R workflow

library(spectropath)

u <- seq(-5, 5, length.out = 500)
f <- dnorm(u, 0, 1) +
  0.25 * dnorm(u, 1.8, 0.45)
path <- cbind(u, f)

path_features(path)

      p2   p_pm    p3u    p3F    p4F    p4T
 -0.3133 0.000 -0.0169 -0.1736 0.4534 0.0132

Method

spectropath provides tools for calculating low-order path-signature coordinates of spectral-line profiles. These are summary statistics of ordered paths, adapted here to line profiles of the form X(u) = (u, F(u)), where u is wavelength or velocity and F is flux.

The returned coordinates describe ordered line morphology: signed area, where asymmetry occurs, whether structure is concentrated in the core or the wings, higher-order bends, and emission–absorption ordering. For convenience, the package also estimates classical summaries such as line flux, equivalent width, FWHM, W80, centroid, and skewness.

Astronomical applications

Line-profile morphology.

IFU kinematics.