Seminarios de Astrofísica en el INAOE

Low Luminosity AGN candidates in SDSS

In a sample of 476931 NELGs obtained from the SDSS DR5 data we find that in 19.5% of the galaxies the emission line [OIII]5007, Hbeta, or both, are missing. The nature of the activity in these galaxies was determined using a diagnostic diagram comparing the equivalent width of [NII]6584 with the ratio [NII]6584/Halpha. The majority of these galaxies are AGN. The Halpha emission lines have a mean FWHM of 400 km/s and mean luminosity of 5.6x10^(39) erg/s, which justify their classification as LLAGN. A study of their star formation histories using STARLIGHT reveals no trace of star formation over the last Gyr period. The hosts of the LLAGNs are early-type, T < 2, with bulges more massive than those of the luminous AGNs.