Structural properties of pseudo-bulges, classical bulges and elliptical galaxies: a Sloan Digital Sky Survey perspective

By D. Gadotti. 2008

390 citations recorded by the source corpus.

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 bulge-to-total ratio than the global Sersic 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 colour-magnitude diagram. Most (though not all) classical bulges are quiescent and populate the red sequence of the diagram. Classical bulges follow a correlation between bulge Sersic 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 bulges. Pseudo-bulges follow a mass-size relation similar to that followed by bars, and different from that followed by classical bulges. In the fundamental plane, pseudo-bulges occupy the same locus as discs. While these results point out different formation processes for classical and pseudo-bulges, we also find a significant overlap in their properties, indicating that the different processes might happen concomitantly. Finally, classical bulges and ellipticals follow offset mass-size relations, suggesting that high-mass bulges might not be simply high-mass ellipticals surrounded by discs.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3ef4b6e332a7fe642364ecd9d5feaa821d59020f

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Citations in the corpus

The GALEX Arecibo SDSS Survey I: gas fraction scaling relations of massive galaxies and first data release (2009, methodology): “As shown in Figure 1 of Weinmann et al. (2009), there is a tight and well-defined correlation between the concentration index and the bulge-to-total ratio derived from full 2-dimensional multi-component fits using the methods presented in Gadotti (2009).”
The cosmic evolution of massive black holes in the Horizon-AGN simulation (2016, methodology): “We have compared our simulated galaxies to distributions of bulgeto-total ratios, Krajnović et al. (2013) for early-type galaxies and Gadotti (2009) for disc galaxies, and Bluck et al. (2014) for a morphological mix.”
Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release (2010, methodology): “A comprehensive insight into galaxy formation and evolution therefore demands consideration of the structural components requiring high spatial resolution imaging on ∼1 kpc scales or better (e.g. Allen et al. 2006; Gadotti 2009).”
BULGES OF NEARBY GALAXIES WITH SPITZER: SCALING RELATIONS IN PSEUDOBULGES AND CLASSICAL BULGES (2010, methodology): “Gadotti (2009) uses the position in μe–re parameter space to study the distribution of bulge properties from SDSS data.”
The Spitzer/IRAC view of black hole–bulge scaling relations (2010, background): “Thus, not all bulges with a low n would be actual pseudobulges from the dynamical point of view (Gadotti 2009).”
MERGERS IN ΛCDM: UNCERTAINTIES IN THEORETICAL PREDICTIONS AND INTERPRETATIONS OF THE MERGER RATE (2010, background): “5%; see e.g. Carollo et al. 1998; Kormendy & Kennicutt 2004; Allen et al. 2006; Ball et al. 2006; Driver et al. 2007; Gadotti 2009).”
The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe (2014, methodology): “This makes the task of robustly determining the bulge/disk mass ratio rather expensive in terms of computational time and the need for human intervention (e.g. Gadotti 2009, Lackner & Gunn 2012).”
Empirical determination of the shape of dust attenuation curves in star-forming galaxies (2011, result): “Comparing ourµ∗ cut with results from the bulge-to-disk decomposition of Gadotti (2009) we find that while some pseudo-bulges have1× 108 µ∗ < 3× 108 and therefore fall into our bulge-less sample, classical bulges and ellipticals all haveµ∗ > 3×108.”
OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES (2010, background): “(ii) The ratio that follows from the correlation between B/T and the concentration index (i.e., R90/R50, where R90 and R50 are the radii enclosing 90 and 50 per cent of the galaxy flux) (Gadotti 2009), which yields B/T = 0.16, 0.13 for TDE1,2.”
On the correlations between galaxy properties and supermassive black hole mass (2011, methodology): “The range of tested parameters for the simulated images was taken from the photometric analysis of nearby elliptical galaxies by Kormendy et al. (2009) and face-on disc galaxies by Gadotti (2009) (but assuming a wider range of axial ratios than the latter).”
A catalogue of 2D photometric decompositions in the SDSS-DR7 spectroscopic main galaxy sample: preferred models and systematics (2014, background): “There has been much recent work on improving photometric decomposition of galaxies (e.g. Gadotti 2009; Simard et al. 2011; Kelvin et al. 2012; Lackner & Gunn 2012; Häußler et al. 2013).”
IMPROVED ESTIMATES OF THE MILKY WAY’S STELLAR MASS AND STAR FORMATION RATE FROM HIERARCHICAL BAYESIAN META-ANALYSIS (2014, background): “Some spirals appear to have no bulge component, whereas in extreme cases the bulge-to-total ratio can be as large as B T 0.8∼ (e.g., Simien & de Vaucouleurs 1986; Gadotti 2009).”
The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time (2016, result): “We compare with the observations of disc galaxies presented in Gadotti (2009), who used dust-corrected stellar masses of galaxies selected from the Sloan Digitial Sky Survey (SDSS) Data Release 2 derived from Kauffmann et al. (2003).”
Physical properties and environments of nearby galaxies (2009, methodology): “Finally, many but not all have concentrated Sérsic-like profiles with high n. Typically, the larger the bulge-to-disk ratio of the galaxy as a whole, the more concentrated the bulge itself is as well (Graham 2001; Gadotti 2009).”
Timing the starburst–AGN connection (2010, background): “At these redshifts the 3 arcsec aperture of the SDSS optical fibres samples the inner 2 kpc radius of the galaxies, so that light from the stars in the bulge dominates the spectrum (Gadotti 2009).”