| Description |
The Baryon Oscillation Spectroscopic Survey (BOSS) collected more than 150,000 quasar spectra. I first create a composite spectrum of 102,150 quasar spectra from 800 A to 3300 A at a signal-to-noise ratio close to1000 per pixel (Delta v of 69 km s^{-1}) as a tool to study the demographics of this large sample. Essential to an accurate construction of this composite spectrum is a correction to account for flux calibration residuals in the BOSS spectrophotometry. I confirm that the resulting flux-calibrated spectrum is consistent with SDSS photometry, thus validating that broad-band and emission features are preserved to better than 5% in the coaddition process. I then use this unprecedented sample to investigate quasar spectral diversity through multiple composite spectra binned by quasar property. I determine the relative influence of quasar luminosity, black hole mass, accretion efficiency, and quasar spectral index on quasar emission line diversity. A comparison of models that predict the dependence of high-ionization emission features on the intrinsic quasar luminosity demonstrates that one particular model is favored. |
