Spectral classification and composites of galaxies in LAMOST DR4

Understand

We study the classification and composite spectra of galaxy in the fourth data release (DR4) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST).

• We select 40,182 spectra of galaxies from LAMOST DR4, which have photometric in- formation but no spectroscopic observations in the Sloan Digital Sky Survey(SDSS).
• These newly observed spectra are re-calibrated and classified into six classes, i.e.
• pas- sive, H{\alpha}-weak, star-forming, composite, LINER and Seyfert using the line intensity (H\b{eta}, [OIII]{\lambda}5007, H{\alpha} and [NII]{\lambda}6585).