Mon. Not. R. Astron. Soc., 456, 3899-3914 (2016/March-2)
Red galaxies with pseudo-bulges in the SDSS: closer to disc galaxies or to classical bulges?
RIBEIRO B., LOBO C., ANTON S., GOMES J.M. and PAPADEROS P.
Abstract (from CDS):
Pseudo-bulges are expected to markedly differ from classical quasi-monolithically forming bulges in their star formation history (SFH) and chemical abundance patterns. To test this simple expectation, we carry out a comparative structural and spectral synthesis analysis of 106 red massive galaxies issued from the Sloan Digital Sky Survey (SDSS), sub-divided into bulgeless, pseudo-bulge and classical bulge galaxies according to their photometric characteristics, and further obeying a specific selection to minimize uncertainties in the analysis and ensure an unbiased derivation and comparison of SFHs. Our 2D photometry analysis suggests that discs underlying pseudo-bulges typically have larger exponential scalelengths than bulgeless galaxies, despite similar integral disc luminosities. Spectral synthesis models of the stellar emission within the 3-arcsec SDSS fibre aperture reveal a clear segregation of bulgeless and pseudo-bulge galaxies from classical bulges on the luminosity-weighted planes of age-metallicity and mass-metallicity, though a large dispersion is observed within the two former classes. The secular growth of pseudo-bulges is also reflected upon their cumulative stellar mass as a function of time, which is shallower than that for classical bulges. Such results suggest that the centres of bulgeless and pseudo-bulge galaxies substantially differ from those of bulgy galaxies with respect to their SFH and chemical enrichment history, which likely points to different formation/assembly mechanisms.
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2016)
galaxies: bulges - galaxies: evolution - galaxies: general - galaxies: stellar content
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<Available at CDS (J/MNRAS/456/3899): tablea1.dat tablea2.dat tablea3.dat tablea4.dat>
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