We have carried out a kinematical and stellar population analysis of the double-barred galaxy NGC357 to provide a more complete characterization of these systems and their role in the formation of galaxy bulges. We clearly identify the presence of the inner bar in the radial velocity and velocity dispersion profiles. The age, metallicity and [Mg/Fe] abundance ratio estimates are very similar to those of ellipticals of equivalent central σ. The [Mg/Fe] value for the bulge of this galaxy suggests formation timescales shorter than 1Gyr.

The chronology of bulge and disk formation is a major unsolved issue in galaxy formation, which impacts on our global understanding of the Hubble sequence. We present colours of the nuclear regions of intermediate-redshift disk galaxies, with the aim of obtaining empirical information of ages of bulges at intermediate z. We work with a sample of 248 galaxies (123 inclined + 125 face-on) from the HST Groth Strip Survey (Groth et al. 1994) and another one with 404 objects (214 inclined + 190 face-on) from the HST GOODS-N field (Giavalisco et al. 2004), covering redshifts 0.1 < z < 1.3. Those samples are apparent-diameter limited at R > 1.4″. We find that, as in the Local Universe, the minor axis color profiles are negative (bluer outward), and fairly gentle, indicating that bulge colours are not distinctly different from disk colours. We apply a conservative criterion to identify bulges and potential precursors of present-day bulges, based on nuclear excess surface brightness above the exponential profile of the outer parts. For galaxies with central brightness excesses, rest-frame colour distributions show a red sequence that confirms the finding of very red bulges by Koo et al. (2005), using independent methods. In contrast, galaxies without central brightness excesses show typical colours of star-forming populations. Clearly, something had truncated star formation in many high-density cores, already at z ~ 1. The truncation epoch is uncertain, 1.5 < z < 10. The colour-magnitude distribution of intermediate-z bulges shows more colour dispersion than that of bulges in the Local Universe. About 50% of bulges are as red as local bulges, while the remainder are significantly bluer, a possible sign of late bulge formation. We also find that bulge colours correlate with integrated galaxy colours and with their disk colours.

Galactic spheroids can form as a result of galaxy interactions and mergers of disks. Detailed analyses of the photometric properties, the intrinsic orbital structure, the line-of-sight velocity distributions and the kinemetry of simulated merger remnants, which depend critically on the geometry and the gas content of the interacting progenitors, indicate that low and intermediate mass rotating ellipticals can form from mergers of disks. The masses and metallicities of all massive ellipticals and the kinematics of some massive non-rotating ellipticals cannot be explained by binary mergers. Thus these galaxies might have formed in a different way.

Based on a NIR morphological study of 25 galaxies in eight Compact Groups (CGs), we find that the galaxies are not in equilibrium but in a process of transformation: late-type galaxies morphological change into earlier types. As much as half of the galaxies in our sample show evidence of ongoing or past mergers.We identify tidal stripping and mergers as the process responsible of this transformation. Our observations also suggest that galaxies in CGs merge more frequently under “dry” conditions (i.e. once they have lost most of their gas).

We present results on the stellar populations of a sample of 18 late-type spirals, based on data acquired with the integral-field spectrograph SAURON at the WHT. We present the two-dimensional line-strength maps, the central line indices, and estimate the star formation time-scale. In an exponentially declining SFR scenario, we find a trend between the time-scale τ and the central velocity dispersion: more massive galaxies show shorter burst durations. A detailed study on these data is published by Ganda et al. (2007).

We show observations obtained with the integral field spectrometer OASIS for the centers of a sample of barred galaxies. The high spatial resolution of the instrument allows to distinguish spatially some structures within these regions as defined by stellar populations of different ages and metallicities. From these data we deduce important clues about the star formation history. But we advise that, in order to obtain adequately the evolutionary sequence, a combination of chemical and synthesis models might be necessary.

We have used our dataset on the abundances of planetary nebulae (PN) to study the chemical evolution of the Galactic bulge. We have derived several relations involving the chemical abundances and computed three classes of models for the Galactic bulge: (i) one-zone, single-infall models, (ii) one-zone, double-infall models and (iii) multizone, double infall models. We conclude that part of the observational data can be understood in terms of the simpler models, but the full understanding of all observational constraints can only be explained by more complex multizone models.

Stellar populations in the Milky Way and in external galaxies are reviewed, based on the conferences and posters presented at this meeting.

Galaxy kinematics at early epochs give a key insight into the assembly of mass. Redshifts z ~ 1 − 3 appear to be the peak of the star formation rate of the Universe, possibly corresponding to the maximal merger activity. 2D velocity fields of late-type galaxies can be used to put important constraints on its total mass and hence on its dark matter halo. As dark halos are thought to govern the rate of galaxy evolution, securing reliable mass measurements for early systems at high redshift is a fundamental observational goal. In addition, accurate inner shape rotation curves, only drawed by 3D spectroscopic studies, should allow to disentangle cosmological scenarii. In the purpose of probing the evolution in masses and mass-to-light ratios of the galaxies during an epoch of expected strong evolution, and setting constrains on their formation and evolution, we present preliminary results obtained from Integral Field NIR Spectroscopy with SINFONI/VLT of a first sample of ten high-z (1.3 < z < 3.3) late-type galaxies selected in the VIMOS/VLT Deep Survey (VVDS). The SINFONI NIR-IFU mode allow to spatially resolve galaxy dynamics using bright rest-frame optical emission lines, in order to perform statistical studies of dynamical masses at this early epochs.

We study the color structure of disk galaxies in the Groth strip at redshifts 0.1 < z < 1.2. Our aim is to test formation models in which bulges form before/after the disk. We find smooth color distributions with gentle outward blueing across the galaxy image: bulges are not distinctly redder than their disks; and bulge colors strongly correlate with global colors. The results suggest a roughly coeval evolution of bulges and disks. About 50% of the nuclei of galaxies with central light excesses above the outer exponential profile hold passively evolving red populations. The remainder 50% are galaxies with central blue colors similar to their disks. They may be bulges in formation, or the central parts of disks with non-exponential surface brightness profiles.

The hierarchical formation of structure suggests that dark halos, and the galaxies they host, are shaped by their merging history. While the idea that mergers between galaxies of equal mass, i.e., major merger, produce elliptical galaxies has received considerable attention, he galaxies that result from minor merger, i.e., mergers between galaxies with a large mass ratio, is much less understood. We have performed a large number of numerical simulations of minor mergers, including cooling, star formation, and black hole growth in order to study this process in more detail. This talk will present some preliminary results of this study, and in particular, the morphology and kinematics of minor merger remnants.

We present highest angular resolution (~ 1″ and 0.35″) mm-interferometric observations of the HCN(1-0), 12CO(1-0) and 12CO(2-1) line emission in the central 300 pc of the late-type spiral galaxy NGC 6946. The data, obtained with the IRAM Plateau de Bure Interferometer (PdBI) shows for the first time a molecular gas spiral in the inner ~ 10″ (270 pc) with a large concentration of molecular gas () within the inner 60 pc, The gas distribution in the central 50 pc has been resolved and is consistent with a gas ring or spiral driven by a bar. Both the distribution of the molecular gas as well as its kinematics can be well explained by the influence of an inner stellar bar of about 400 pc length as tested via a qualitative model for the gas flow. NGC 6946 is a prime example of molecular gas kinematics being driven by a small-scale, secondary stellar bar.

For the first time, it is possible to directly compare the location of (dense) giant molecular clouds with that of (optically) visible HII regions in space-based images. We use the 3 mm continuum and the HCN emission to estimate in the central 50 pc the star formation rates in young clusters that are still embedded in their parent clouds and hence are missed in optical and near-IR surveys of star formation. The amount of embedded star formation is about 1.6 times as high as that measured from HII regions alone, and appears roughly evenly split between ongoing dust-obscured star formation and very young giant molecular cloud cores that are just beginning to form stars. The build-up of central mass seems to have continued over the past ≥ 10 Myrs, to have occurred in an extended (albeit small) volume around the nucleus, and to be closely related to the presence of an inner bar.

We measure the non-axisymmetry in the luminosity distribution in the central few kpc of a sample of advanced mergers of galaxies, by analyzing their 2MASS images. All mergers show a high central asymmetry: the centres of isophotes show a striking sloshing pattern with a spatial variation of upto 30% within the central 1 kpc; and the Fourier amplitude for lopsidedness (m = 1) shows high values upto 0.2 within the central 5 kpc. The central asymmetry is estimated to be long-lived, lasting for ~ a few Gyr or ~ 100 local dynamical timescales. This will significantly affect the dynamical evolution of this region, by helping fuel the central active galactic nucleus, and also by causing the secular growth of the bulge driven by lopsidedness.

Bulges are a major galaxy component in the nearby universe, and are one of the primary features that differentiates and defines galaxies. The origin of bulges can be directly probed in part by examining distant galaxies to search for high redshift bulges, and to study the properties of bulges in formation. We review the evidence for bulges at high redshift in this article, and how by studying bulges through a variety of approaches, including through morphological, colour, and stellar mass selection, we can determine when and how these systems assembled. We argue that the majority of the most massive ‘classical’ bulges are in place by z ~ 1.5 − 2, and likely formed very early through major mergers. Other, likely lower mass, bulges form through a secular process along with their disks. Direct observations suggest that these two formation processes are occurring, as spheroids are commonly seen at z < 1, as are disks and spiral galaxies in the form of luminous diffuse objects, clump-clusters, and chain galaxies. However, bulge+disk systems are relatively rare until z ~ 1, suggesting that this structural assembly occurred relatively late.

Gravity is nearly a universal constant in the cusp of an NFW galaxy halo. Inside this external field an isothermal gas sphere will collapse and trigger a starburst if above a critical central pressure. Thus formed spheroidal stellar systems have Sersic-profile and satisfy the Faber-Jackson relation. The process is consistent with observed starbursts. We also recover the MBH − σ* relation, if the gas collapse is regulated or resisted by the feedback from radiation from the central BH.

The Sloan Digital Sky Survey (SDSS) and photometric/spectroscopic surveys of two z ~ 0.8 massive clusters of galaxies and the Chandra Deep Field-South (CDFS) are used to construct volume-limited, stellar mass-selected samples of galaxies at redshifts 0 < z < 1 in a large range of environments. Morphologies are determined visually and with an automated method, using the Sérsic parameter n and a measure of the residual from the Sérsic model fits, called “bumpiness”, to distinguish different morphologies. The agreement between the visual and automated methods is excellent. The fraction of E+S0 galaxies with masses larger than ~ 0.5 M* is 40 − 50% in the field, and > 80% in the clusters, without significant changes with redshift. Therefore, we find that the morphology-density relation (MDR) for galaxies more massive than ~ 0.5 M* has remained constant since at least z ~ 0.8. This implies that galaxy evolution (in terms of mass, star formation, color, morphology, etc.) must happen such that the MDR does not change.

Early-type galaxies, considered as large bulges, have been found to have had a much-more-than-boring star formation history in recent years by the UV satellite GALEX. The most massive bulges, brightest cluster galaxies, appear to be relatively free of young stars. But smaller bulges, normal ellipticals and lenticulars, often show unambiguous sign of recent star formation in their UV flux. The fraction of such UV-bright bulges in the volume-limited sample climbs up to the staggering 30%. The bulges of spirals follow similar trends but a larger fraction showing signs of current and recent star formation. The implication on the bulge formation and evolution is discussed.

We examine the photometric and structural properties of early-type galaxies derived from the ACS Virgo and Fornax Cluster Surveys, supplementing these data with previously published or newly reanalysed data for additional early-type galaxies in Virgo, Fornax and the Local Group. As we have noted elsewhere, Sérsic models are found to provide accurate representations of the observed brightness profiles on scales greater than a few percent of the effective radius, Re. On smaller scales, the brightness profiles of bright (MB ≳ −20) galaxies show central deficits with respect to the inward extrapolation of the Sérsic models; fainter galaxies usually show central excesses. Fainter than MB ≈ −20, we find a continuity in the photometric and structural scaling relations: i.e., between absolute magnitude, central surface brightness, Sérsic index, effective radius, and the surface brightness measured at, and averaged within, the effective radius. There is no evidence for a “dwarf/giant dichotomy” — a conclusion consistent with a number of recent studies but contrary to some earlier claims.

We present a study of the internal kinematics and stellar populations of early-type galaxies in the Fornax cluster. 10 galaxies in a luminosity range of −21.8≤MB≤−17.4 were observed with the integral field units (IFU) of Gemini South GMOS and VLT-VIMOS. Velocity maps and age-metallicity diagrams are presented for NGC 1404 and NGC 1419.

Future space mission of astrometric satellite, GAIA and JASMINE (Japan Astrometry Satellite Mission for Infrared Exploration), will produce astrometric parameter, such as positions, parallaxes, and proper motions of stars in the Galactic bulge. Then kinematical information will be obtained in the future. Accordingly it is expected that our understanding of the dynamical structure will be greatly improved. Therefore it is important to make a method to construct a kinematical and dynamical structure of the Galactic bulge immediately.