1. 1 The Population and Luminosity Function of AGNs from SDSS Lei Hao Collaborators: Michael Strauss SDSS collaboration Princeton University Carnegie Symposium (I) 2002

2. 2 Data Sample 114,772 galaxy spectra (mostly r<17.7) in 1151 sq degrees 58,038 low redshift (z<0.33) emission line galaxies. AGNs are identified by their emission line characteristics.

3. 3 Stellar Subtraction The emission lines of AGN are often contaminated by the host galaxy absorption lines. To correct the contamination,the underlying stellar absorption spectrum is removed from the original spectrum.

4. 4 AGN selections – FWHM(Hα)>1,200 km/s – 3069 are identified Broad Line AGNs Narrow Line AGNs Distinguishing AGNs from star-forming galaxies Theoretical separation lines predicted by Kewley et.al 2001

5. 5 AGN selections – FWHM(Hα)>1,200 km/s – 3069 are identified Broad Line AGNs – 3456 are identified Narrow Line AGNs

6. 6 The Redshift and Magnitude Distribution AGN sample – r-band Petrosian <17.7 –1281 broad line AGNs –2696 narrow line AGNs

7. 7 The Luminosity Function (LF) of AGNs We measure the luminosity function as a function of Hα luminosity. Assumption –The luminosity of the nuclei is independent of the luminosity of its host galaxy. We measure the probability function for each AGN. Nuclei Spectrum Host galaxy Weakened nuclei Noise New Spectrum AGN?

8. 8 Luminosity Function Result

9. 9 Luminosity Function Result and Check Divide the AGN sample into subgroups by their redshifts. For each group, evaluate the expected AGN luminosity distribution using the LF calculated. If LF is correct, the expected distribution should match the observed distribution.

10. 10 Luminosity Function Result and Check Divide the AGN sample into subgroups by their host galaxy magnitudes. No systematic discrepancy  the nuclei luminosity is not strongly correlated with its host galaxy luminosity.

11. 11 Conclusion From SDSS, we compiled an AGN catalog including over 3000 broad-line AGNs and over 3000 narrow-line AGNs The LF of the AGNs are calculated and checked. Future work –AGN LF evolution –The connection btw. AGNs and host galaxies –The accretion rate of AGNs –Radio and X-ray properties –……

12. 12 Assumption Evaluation Galaxy Magnitude vs. Hα Luminosity 0.01<z<0.03 0.03<z<0.06 0.06<z<0.09 0.09<z<0.12 0.12<z<0.14 0.14<z<0.2 0.12<z<0.14