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Mon. Not. R. Astron. Soc. 393, 15311552 (2009) doi:10.1111/j.1365-2966.2008.14257.x Structural properties of pseudo-bulges, classical bulges and elliptical
 

Summary: Mon. Not. R. Astron. Soc. 393, 1531­1552 (2009) doi:10.1111/j.1365-2966.2008.14257.x
Structural properties of pseudo-bulges, classical bulges and elliptical
galaxies: a Sloan Digital Sky Survey perspective
Dimitri A. Gadotti
Max-Planck-Institut f¨ur Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching bei M¨unchen, Germany
Accepted 2008 November 14. Received 2008 November 13; in original form 2008 October 9
ABSTRACT
We have performed 2D bulge/bar/disc decompositions using g, r and i-band images of a
representative sample of nearly 1000 galaxies from the Sloan Digital Sky Survey. We show
that the Petrosian concentration index is a better proxy for the bulge-to-total ratio than the
global S´ersic index. We show that pseudo-bulges can be distinguished from classical bulges
as outliers in the Kormendy relation. We provide the structural parameters and distributions
of stellar masses of ellipticals, classical bulges, pseudo-bulges, discs and bars, and find that
32 per cent of the total stellar mass in massive galaxies in the local universe is contained in
ellipticals, 36 per cent in discs, 25 per cent in classical bulges, 3 per cent in pseudo-bulges
and 4 per cent in bars. Pseudo-bulges are currently undergoing intense star formation activity
and populate the blue cloud of the colour­magnitude diagram. Most (though not all) classical
bulges are quiescent and populate the red sequence of the diagram. Classical bulges follow a
correlation between the bulge S´ersic index and bulge-to-total ratio, while pseudo-bulges do not.
In addition, for a fixed bulge-to-total ratio, pseudo-bulges are less concentrated than classical

  

Source: Alexei, Dimitri - European Southern Observatory

 

Collections: Physics