Spectral classification by PCA
Apply Principal Component analysis to spectra.
PC1: emission lines correlate with blue continuum.
PC2: strength of emission lines without continuum.
PC3: strength of Balmer lines w.r.t. other emission.
Classify spectral types in PC1-PC2 plane using sample of Kennicutt to set bounds.
Further work:
- effect of spectro-photometric errors;
- self-classification algorithms;
- calibration against spectral models.