The first step to discover the formation and suppression of AGN BLRs

   Broad emission lines from the BLRs are fundamental characters of AGNs. However, there is so far no clear information on the formation and/or suppresion of AGN BLRs. As one special kinds of AGN, naked AGNs (or BLR-Less AGNs) AGNs without BLRs in the centrAl regions, should provide one powerful tool to study the mysterious evolution from the birth time to the dead time for the AGN BLRs. Until now, there are less than 70 naked AGN reported in the literatures through different methods.  Therefore, it is necessary to find more naked AGNs by one non-biased method. Through the SDSS Stripe82 photometry variability Database and the corresponding SDSS specscopic information, we report so far the largest sample of 281 naked AGNs from the parent sample of more than 100000 emission line objects.  

The naked AGNs have clearly apparent photometry variabilities, apparent power law continuum emissions but no broad lines in their SDSS spectra. The large sample of Naked AGNs should lead us to find further information on the formation and suppresion on the AGN BLRs.  

By with ZHANG Xueguang

   The left panel shows the photometry RMS variability properties for the emission line galaxies in contour, QSOs in contour and the selected naked

AGNs as circles and five-point stars. The right panel shows the correspondingPearson's coefficients between two SDSS band light curves.

The research work by XueGuang Zhang has been accepted and to be published in MNRAS (http://mnras.oxfordjournals.org/content/early/2013/12/09/mnras.stt2226)