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The MUSE TIMER Survey has obtained high signal and high spatial resolution integral-field spectroscopy data of the inner ~ 6×6 kpc of 21 nearby massive disc galaxies. This allows studies of the stellar kinematics of the central regions of massive disc galaxies that are unprecedented in spatial resolution. We confirm previous predictions from numerical and hydrodynamical simulations of the effects of bars and inner bars on stellar and gaseous kinematics, and also identify box/peanuts via kinematical signatures in mildly and moderately inclined galaxies, including a box/peanut in a face-on inner bar. In 20/21 galaxies we find inner discs and show that their properties are fully consistent with the bar-driven secular evolution picture for their formation. In addition, we show that these inner discs have, in the region where they dominate, larger rotational support than the main galaxy disc, and discuss how their stellar population properties can be used to estimate when in cosmic history the main bar formed. Our results are compared with photometric studies in the context of the nature of galaxy bulges and we show that inner discs are identified in image decompositions as photometric bulges with exponential profiles (i.e., Sérsic indices near unity). [ABSTRACT FROM AUTHOR]

Using images from the Hubble Space Telescope and Sloan Digital Sky Survey, we have computed both parametric and non-parametric measures, and examined the evolution in size, concentration, stellar mass, effective stellar mass density and asymmetry for a sample of 600 disc galaxies from z ~ 1 till z ~ 0. We find that disc galaxies have gained more than 50 per cent of their present stellar mass over the last 8 Gyr. Also, the increase in disc size is found to be peripheral. While the average total (Petrosian) radius almost doubles from z ~ 1 to z ~ 0, the average effective (half-light) radius undergoes a marginal increase in comparison. This indicates that galaxies grow more substantially in their outskirts, and is consistent with the inside-out growth picture. The substantial increase in mass and size indicates that accretion of external material has been a dominant mode of galaxy growth, where the circumgalactic environment plays a significant role. [ABSTRACT FROM PUBLISHER]

Image decomposition of galaxies is now routinely used to estimate the structural parameters of galactic components. In this work, I address questions on the reliability of this technique. In particular, do bars and AGN need to be taken into account to obtain the structural parameters of bulges and discs? And to what extent can we trust image decomposition when the physical spatial resolution is relatively poor? With this aim, I performed multi-component (bar/bulge/disc/AGN) image decomposition of a sample of very nearby galaxies and their artificially redshifted images, and verified the effects of removing the bar and AGN components from the models. Neglecting bars can result in a overestimation of the bulge-to-total luminosity ratio of a factor of two, even if the resolution is low. Similar effects result when bright AGN are not considered in the models, but only when the resolution is high. I also show that the structural parameters of more distant galaxies can in general be reliably retrieved, at least up to the point where the physical spatial resolution is ≈ 1.5 Kpc, but bulge parameters are prone to errors if its effective radius is small compared to the seeing radius, and might suffer from systematic effects. I briefly discuss the consequences of these results to our knowledge of the stellar mass budget in the local universe, and finish by showing preliminary results from a large SDSS sample on the dichotomy between classical and pseudo-bulges. [ABSTRACT FROM PUBLISHER]

In an effort to elevate to higher grounds our understanding on the impact of the formation and evolution of bars in the formation and evolution of galaxies, we have developed a diagnostic tool to distinguish between recently formed and evolved bars. Our method was applied in the study of a sample of 14 galaxies and revealed that, apparently, AGN activity tends to appear in galaxies which have young bars rather than evolved bars. This suggests that the time scale for the fueling of AGN by bars is short, and may help to explain, for instance, why there is not a clear correlation between the presence of bars and AGN in galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html [ABSTRACT FROM PUBLISHER]

The structural parameters of bulges, disks and bars of a sample of nearly 1000 nearby galaxies are being determined through sophisticated image decomposition in the g, r and i bands. The sample is carefully drawn from the Sloan Digital Sky Survey Data Release 2 (SDSS DR2), contains 963 galaxies, of which 407 host AGN, and we show that it is representative of the galaxy and AGN populations in the local universe. A large number of other physical properties have also been determined for these galaxies within the SDSS collaboration. With these data, we reinforce several recent studies and find a number of results leading to new insights into how the different galaxy components relate to each other and the extent to which the hosts galaxies of AGN differ from quiescent galaxies. [ABSTRACT FROM PUBLISHER]

Using results from parametric multi-component multi-band image fitting of 1000 local massive galaxies in the SDSS, I investigate scaling relations of elliptical galaxies and bulges of disk galaxies. I show that ellipticals and bulges occupy different loci in both the edge-on and face-on views of the fundamental plane. In addition, ellipticals and bulges have offset mass-size relations (see Fig. 1). These results imply that massive bulges are not just massive ellipticals with a surrounding disk, a misconception driven by early studies. This is evidence that massive ellipticals and bulges have different formation histories, with important consequences for studies on galaxy formation and evolution. Full details can be seen in Gadotti (2009). [ABSTRACT FROM PUBLISHER]

We obtained stellar ages and metallicities via spectrum fitting for a sample of 575 bulges with spectra available from the SDSS. Using the whole sample, where galaxy stellar mass distributions for barred and unbarred galaxies are similar, we find that the distribution of bulge ages in barred galaxies shows an excess of populations younger than 4 Gyr, when compared to bulges in unbarred galaxies. KS statistics confirm that the age distributions are different with a significance of 99.94%. If we select sub-samples for which the bulge stellar mass distributions are similar for barred and unbarred galaxies, this excess vanishes for galaxies with low-mass bulges, while for more massive bulges we find a bimodal stellar age distribution for barred galaxies only, corresponding to two normal distributions with mean ages of 10.4 and 4.7 Gyr (see Fig. 1). These results lend strong support to models in which bars trigger star formation activity in the centers of galaxies. We also find twice as much AGN among barred galaxies, as compared to unbarred galaxies, for low-mass bulges. Full results are in Coelho & Gadotti (2011). [ABSTRACT FROM PUBLISHER]

In an effort to obtain further observational evidences for secular evolution processes in galaxies, as well as observational constraints to current theoretical models of secular evolution, we have used BVRI and Ks images of a sample of 18 barred galaxies to measure the lengths and colours of bars, create colour maps and estimate global colour gradients. In addition, applying a method we developed in a previous article, we could distinguish for 7 galaxies in our sample those whose bars have been recently formed from the ones with already evolved bars. We estimated an average difference in the optical colours between young and evolved bars that may be translated to an age difference of the order of 10 Gyr, meaning that bars may be long standing structures. Moreover, our results show that, on average, evolved bars are longer than young bars. This seems to indicate that, during its evolution, a bar grows longer by capturing stars from the disk, in agreement with recent numerical and analytical results. [ABSTRACT FROM PUBLISHER]