2016/09/12 by L. Morelli, M. Parmiggiani, Marco Parmiggiani +7 · 2 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Bulge #Disc galaxy #Elliptical galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Metallicity #Photometry (optics) #Physics #Spiral galaxy #Star formation #Stars #Stellar mass #Stellar population #Stellar, planetary, and galactic studies #Surface brightness #Surface brightness fluctuation #Velocity dispersion #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stw2285
MNRAS in press. 29 pages, 12 figures, 10 Table. Figure A2 have lower resolution than in the original paper to match the arxiv requirements
openalex publication_date 2016/09/12 · arxiv created 2016/09/28 · arxiv updated 2016/10/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present photometry and long-slit spectroscopy for 12 S0 and spiral galaxies selected from the Catalogue of Isolated Galaxies. The structural parameters of the sample galaxies are derived from the Sloan Digital Sky Survey i-band images by performing a two-dimensional photometric decomposition of the surface brightness distribution. This is assumed to be the sum of the contribution of a Sérsic bulge, an exponential disc, and a Ferrers bar characterized by elliptical and concentric isophotes with constant ellipticity and position angles. The rotation curves and velocity dispersion profiles of the stellar component are measured from the spectra obtained along the major axis of galaxies. The radial profiles of the |\rm H\small β |, Mg and Fe line-strength indices are derived too. Correlations between the central values of the Mg2 and 〈Fe〉 line-strength indices and the velocity dispersion are found. The mean age, total metallicity and total α/Fe enhancement of the stellar population in the centre and at the radius, where the bulge gives the same contribution to the total surface brightness as the remaining components, are obtained using stellar population models with variable element abundance ratios. We identify intermediate-age bulges with solar metallicity and old bulges with a large spread in metallicity. Most of the sample bulges display supersolar α/Fe enhancement, no gradient in age and negative gradients of metallicity and α/Fe enhancement. These findings support a formation scenario via dissipative collapse where environmental effects are remarkably less important than in the assembly of bulges of galaxies in groups and clusters.