We study the large-scale spatial distribution of low-redshift quasars and Seyfert 1 galaxies using a sample of 106 luminous emission-line objects ( \overline { M } _ { B } \approx - 23 ) selected by their H \alpha emission lines in a far-red objective prism survey ( 0.2 < z < 0.37 ) .
Of the 106 objects , 25 were previously known AGN ( Veron-Cetty and Veron 2000 ) , and follow-up spectroscopy for an additional 53 objects ( including all object pairs with separation r < 20 \mbox { $h ^ { -1 } $ Mpc } ) confirmed 48 AGN and 5 narrow emission-line galaxies ( NELGs ) .
The calculated amplitude of the spatial two-point correlation function for the emission-line sample is A = 0.4 \cdot \overline { \xi } ( r < 20 \mbox { $h ^ { -1 } $ Mpc } ) \cdot 20 ^ { 1.8 } = 142 \pm 53 .
Eliminating the confirmed NELGs from the sample we obtain the AGN clustering amplitude A = 98 \pm 54 .
Using Monte Carlo simulations we reject the hypothesis that the observed pair counts were drawn from a random distribution at the 99.97 % and 98.6 % confidence levels for the entire sample and the AGN subset respectively .
We measure a decrease in the quasar clustering amplitude by a factor of 3.7 \pm 2.0 between z = 0.26 and z \approx 1.5 , and present the coordinates , redshifts , and follow-up spectroscopy for the 15 previously unknown AGN and 4 luminous NELGs that contribute to the clustering signal .