bettermoments 1.0.0

A robust method for inferring line-of-sight velocities from Doppler shifted spectra

bettermoments

Measuring precise line-of-sight velocities is essential when looking for small scale deviations indicative of, for example, embedded planets. bettermoments helps you measure such velocities.

Approach

Rather than fitting the full line profile with an analytical expression, we fit a quadratic to the the peak pixel and its two adjacent pixels. For a single component, this has been shown om Vakili & Hogg (2016) to provide comparable precision to fitting the full spectrum with the true underlying profile. Thus, in the extremely likely scenario where the underlying profile is not known, this method will out perform more common methods, such as the intensity weighted average.

Usage

To start, install the bettermoments package by executing

pip install bettermoments

Then you can execute this module using

import bettermoments as bm

x_max, x_max_sigma, y_max, y_max_sigma = pm.quadratic(data, uncertainties)

See the docstring for the bettermoments.quadratic function for more information on the available options.