Environmental dependence of the presence of active galactic nuclei (AGNs) in the volume-limited Main galaxy samples of SDSS DR6

Using two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 6 (SDSS DR6) above and below the value of (M_r^*), we have explored the environmental dependence of the AGN fraction. It is found that the fraction of AGNs declines substantially with increasing local density in the luminous volume-limited sample, but in the faint volume-limited sample this change is very weak. We also note that the presence of AGNs is not correlated with the stellar mass.