your ID: 0254 First Name: Marek Last Name: Nikolajuk Affiliation: University of Bialystok Title: Black hole masses in NLS1 galaxies from the X-ray excess variance method Authors: Nikolajuk M., Czerny B., Gurynowicz P. Topic: 1 Session: poster Abstract: We estimate black hole masses in Narrow Line Seyfert 1 (NLS1) galaxies at the basis of their X-ray excess variance. We apply the standard approach appropriate for Broad Line Seyfert 1 (BLS1) galaxies. In general, we find that the obtained masses are by a factor about 20 too small to agree with values obtained from other methods (reverberation, stellar dispersion). However, we can see that a small subset of our NLS1 objects do not require that multiplication, or the correction factor is less than 3. We find that this subset have got a soft X-ray photon index, Gamma_{0.1-2keV}, smaller than 2. We thus postulate that this subclass of NLS1 actually belongs to BLS1.