The spectral variability of quasar SDSS J030639.57+000343.1

We compiled a sample of 60 quasars with spectroscopy on at least six epochs from the Sloan Digital Sky Survey (SDSS) to study the variabilities of the spectral shape, the continuum and the emission lines luminosity. In this paper, we present the results of SDSS J030639.57+000343.1. We found a strong anti-correlation between the continuum luminosity at $5100 \AA$ and the spectral index, implying a bluer-when-brighter trend. The luminosity of the broad $\rm H_\alpha$ line is proportion to the continuum luminosity at $5100 \AA$. Correspondingly, we did not find strong correlation between the equivalent width of broad $\rm H\alpha$ and the continuum luminosity, i.e. no baldwin effect of broad $\rm H\alpha$ in this source.