Redmonster Redshift Measurement and Spectral Classification
redmonster software is a sophisticated and flexible set of Python utilities for redshift measurement, physical parameter measurement, and classification of one-dimensional astronomical spectra. A full description of the software is given in Hutchinson et al. (in prep.).
The software used is called
redmonster and is publicly available in a GitHub repository.
The essential strategy for redshift fitting is to perform, at each potential redshift, a least-squares fit to each spectrum given the uncertainties, using a fairly general set of theoretical models, for galaxies, for stars, and for quasars. The best fit model and redshift is chosen and reported for the object. The fits are applied without regard to the target category of the object (so that if an object targeted as a galaxy turns out to be a star, we can identify it as such).
Redshift & Classification
The redmonster software approaches redshift measurement and classification as a χ2 minimization problem by cross-correlating the observed spectrum with each spectral template within a template class over a discretely sampled redshift interval.