UM625: A Seyfert 1 galaxy with a low-mass black hole and a pseudobulge

Speaker: Ning Jiang (USTC)

Time: August 19, 2010 (Thursday), 14:00PM

Location: Large conf. room, 3rd floor

Abstract:

UM625 was identified previously as a Seyfert 2 galaxy, yet after our analysis broad Ha and Hb lines are revealed evidently from its recent spectrum taken by Sloan Digital Sky Survey. According to the width and luminosity of broad Hs, the virial mass of the central black hole is 1.7*10^6 M_sun, in the so-called intermediate mass regime. HST images shows that the host galaxy is a nearly face-on S0 galaxy with an exponential surface brightness profile in the near-infrared, and yet more spheroidal-like in the R band with a steeper profile of Sersic n = 2; and that a star-formation semi-ring is located on scales of ~150-400 pc. Moreover, according to our careful 1-dimensional and 2-dimensional decompositions of the HST WFPC2/PC1 F606W image, a central stellar component is revealed with an effective radius of 72+/15 pc, slightly disky isophotes and a rather flat surface brightness profile (Sersic n < 1), suggestive of a pseudobulge. The black hole mass and bulge properties are in good accordance with the relationships founded in local massive galaxies, which suggests a solution to the puzzle that M_BH-sigma_* and M_BH-L_bulge relations cannot hold both in low-mass systems.


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