A semi-analytic model of galaxy formation with and without active galactic nuclei feedback is used to study the nature of possible building blocks (BBs) of z = 0 galaxies, including those of Milky-Way types. We find that BBs can show an important range of properties arising from environmental variables such as host halo mass, and whether a galaxy is a satellite within its host halo; the stellar formation histories are comparatively faster and the chemical enrichment is more efficient in BBs than in surviving satellites, in accordance with recent metallicity measurements for the Milky Way. These results can be used in combination with observational constraints to continue probing the ability of the cold dark-matter scenario to reproduce the history of galaxy demography in the Universe.

In cold dark matter cosmologies, the most massive dark matter halos are predicted to undergo rapid growth at z < 1. While there is the expectation that massive galaxies will also rapidly grow via merging, recent observational studies conclude that the stellar masses of the most massive galaxies grow by just ~ 30% at z < 1. We have used the observed space density and clustering of z < 1 red galaxies in Boötes to determine how these galaxies populate dark matter halos. In the most massive dark matter halos, central galaxy stellar mass is proportional to halo mass to the power of a ~1/3 and much of the stellar mass resides within satellite galaxies. As a consequence, the most massive galaxies grow slowly even though they reside within rapidly growing dark matter halos.

We present results from a high resolution cosmological galaxy formation simulation called Mare Nostrum and a ultra-high resimulation of the first 500 million years of a single, Milky Way (MW) sized galaxy. Using the cosmological run, we measure UV luminosity functions and assess their sensitivity to both cosmological parameters and dust extinction. We find remarkably good agreement with the existing data over the redshift range 4 < z < 7 provided we adopt the favoured cosmology (WMAP 5 year parameters) and a self-consistent treatment of the dust. Cranking up the resolution, we then study in detail a z = 9 protogalaxy sitting at the intersection of cold gas filaments. This high-z MW progenitor grows a dense, rapidly spinning, thin disk which undergoes gravitational fragmention. Star formation in the resulting gas clumps rapidly turns them into globular clusters. A far reaching galactic wind develops, co-powered by the protogalaxy and its cohort of smaller companions populating the filaments. Despite such an impressive blow out, the smooth filamentary material is hardly affected at these redshifts.

We discuss our ongoing project analyzing N-body/smoothed-particle hydrodynamics simulations of isolated and merging galaxies, performed using GADGET-2 (Springel 2005), with the 3-D adaptive grid, polychromatic Monte Carlo radiative transfer code SUNRISE (Jonsson 2006). We apply commonly used UV, optical, and IR star formation rate (SFR) indicators to the integrated spectral energy distributions (SEDs) of the simulated galaxies in order to determine how well the SFR indicators recover the instantaneous SFR in the simulations. The models underlying each SFR indicator must necessarily make assumptions about physical properties of the galaxies, e.g., the star formation history (SFH), whereas all such properties are known in the simulations. This enables us to test and compare SFR indicators in a way that is complementary to observational studies. We present one preliminary result of interest: even after correcting the Hα luminosity for dust using the Calzetti et al. (2000) attenuation law the SFR is significantly underestimated for simulated galaxies with SFR ≳ 10 M⊙ yr−1.

We have obtained several hundred very deep spectra with DEIMOS/Keck in order to estimate the galactic mass flux density at intermediate redshifts (0.6 < z < 0.9) from the "blue cloud" to the red sequence across the so-called “green valley”, the intermediate region in the color-magnitude plot between those two populations. We use spectral indices (specifically Dn(4000) and Hδ, A) to determine star formation histories. Together with an independent measurement of number density of galaxies in each bin of the color-magnitude plot, one can infer the rate at which galaxies from a given sample are transiting through that bin. Measuring this value for all magnitude values, studies at lower redshift determined that the mass flux density in the green valley is comparable to both the mass build-up rate of the red sequence and the mass loss rate from the blue cloud. We show preliminary results for our intermediate redshift sample.

The Dark Energy Survey (DES) will cover 5000 sq. deg. in grizY filters. Although its main goals are related to cosmology, it will yield photometric measurements of over 108 stars, most of them belonging to the Galaxy. DES will increase the sampling depth of very low-luminosity stellar and sub-stellar species, such as white, red, and brown dwarfs, by a factor of several as compared to SDSS. The structure of the Galactic halo, including its complex sub-structures caused by accretion remnants and globular cluster tidal tails, will also be probed and analyzed. DES will also allow comparison of star counts between Northern and Southern Galactic hemispheres to unprecedented detail. Finally, a significant sample of stars in the outskirts of the Large Magellanic Cloud (LMC) will be studied, providing new light into the debate about the existence of an LMC spheroidal component. These, among other important research goals attainable with the DES stellar data, are discussed in this contribution.

People working on stellar populations can look forward to an exciting decade ahead. Investigations of stellar populations lie at the heart of the science cases being used to justify the development of upcoming telescopes and emerging instrumentation technologies. Examples abound, but I will focus on three case studies: (1) Wide field astronomy with upcoming ground-based and space-based survey facilities; (2) Adaptive optics, which has the potential to revolutionize our understanding of stellar populations in both nearby and distant galaxies; (3) The James Webb Space Telescope, which may well extend the reach of stellar population work to encompass the full range of the star-forming history of the Universe. However, most of these developments will require extensive advance preparation in order to be used effectively. The time to start that preparation is now (if not yesterday). Three areas which need urgent development are highlighted in these proceedings: (1) We need a wide-field high-resolution spectroscopic capability to augment wide-area imaging surveys; (2) We need a set of AO-friendly extragalactic deep fields in order to exploit upcoming AO-fed instrumentation; and (3) Existing tools for population synthesis modeling need to be extended in order to incorporate the effects of dust. Because the physics of dust creation and destruction is so complicated and uncertain, the latter capability sounds almost impossibly hard to develop, but in this talk I will argue that some simple approaches already exist that allow dust to be injected rather naturally into population synthesis models. I will show a concrete example where incorporation of dust into spectral synthesis models allows one to detect and characterize rate of formation of circumstellar disks at high redshifts.

With the coming generation of instruments and telescopes capable of spectroscopy of high redshift galaxies, the spectral synthesis technique in the rest-frame UV and Far-UV range will become one of a few number of tools remaining to study their young stellar populations in detail. The rest-frame UV lines and continuum of high redshift galaxies, observed with visible and infrared telescopes on Earth, can be used for accurate line profile fitting such as Pvλλ1118, 1128, Ciiiλ1176, and Civλ1550. These lines are very precise diagnostic tools to estimate ages, metallicities, and masses of stellar populations.

Here we discuss the potential for spectral synthesis of rest-frame UV spectra obtained at the Keck telescope. As an example, we study the 8 o'clock arc, a lensed galaxy at z=2.7322. We show that the poor spectral type coverage of the actual UV empirical spectral libraries limits the age and metallicity diagnostic. In order to improve our knowledge of high redshift galaxies using spectral synthesis, UV stellar libraries need to be extended to obtain accurate age, metallicity, and mass estimates likely to be occuring in young stellar populations observed in the early universe.

Over the next 5 years the VVV collaboration (Vista Variable in the Via Lactea) will conduct an extensive survey of the galactic bulge and disk in the near-IR, using the new VISTA telescope. This public survey covers a field of 520 sqr. deg, including not only regions of high star formation, but also 33 known globular clusters and ~350 open clusters. The final product will be a deep IR atlas in 5 passbands for ~109 point sources among which we expect 106 variable stars. These will be produce a 3-D map of the surveyed region using well-understood primary distance indicators such as RR Lyrae stars. The observations will be combined with data from MACHO, OGLE, EROS, VST, Spitzer, HST, Chandra, Integral, and ALMA for a complete understanding of the variable sources in the inner Milky Way. Several important implications for the history of the Milky Way, for globular cluster evolution, for the population census of the bulge and center, and for the pulsation theory will follow from this survey.

SMART is a model to derive both star formation history and chemical evolution simultaneously from color-magnitude diagrams of resolved stars in a galaxy. We present current progress and discuss the prospects of SMART for the next decade.

The study of stellar populations in galaxies is entering a new era with the availability of large and high-quality data bases of both observed galactic spectra and state-of-the-art evolutionary synthesis models. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has a 4m primary, and a 5 degree field of view, accommodate as many as 4000 optical fibers. It can obtain the spectra of objects as faint as down to B = 20.5 mag with an exposure of 1.5 hour, promising a very high spectrum acquiring rate of ten-thousands of spectra per night. In this talk, we introduce the progress of the LAMOST project, its surveys and show the spectral synthesis code that we are developing for the LAMOST ExtraGAlactic Surveys (LEGAS).

We give an overview of the science case for spectroscopy of resolved stellar populations beyond the Local Group with the European Extremely Large Telescope (E-ELT). In particular, we present science simulations undertaken as part of the EAGLE Phase A design study for a multi–integral-field-unit, near-infrared spectrograph. EAGLE will exploit the unprecedented primary aperture of the E-ELT to deliver AO-corrected spectroscopy across a large (38.5 arcmin2) field, truly revolutionising our view of stellar populations in the Local Volume.

To conclude this exciting conference on Stellar Populations: Planning for the Next Decade, we have sacrificed the traditional ‘conference summary’ for an opinion poll among all invited speakers on two issues: the most important achievements in the field of stellar populations over the past few years; and the most important challenges for the coming decade. The answers to this poll were remarkably uniform, indicating that the field of stellar populations has a clear future in the era when several new major research facilities are coming online.

In this work the location of a sample of 174 flux measurements (planetary nebulae, S, D, D'-type Symbiotic Star (SS) and six peculiar objects) on the λ5007/Hβ vs. λ4363/Hγ diagnostic diagram are compared, in order to investigate possible differences in electron density and temperature among them. Helium abundances, electron density and temperature were obtained for five D'-type SS and HD149427 (PC 11). In order to calculate them, expressions normally used for objects with low density were modified, in such a way that they can be used in objects with higher densities.

We have explored late-type spiral galaxies with truncated radial surface brightness profiles. Based on the study of optical color profiles, Bakos et al. (2008) suggested that truncated (TYPE II) galaxies have a generally older stellar population in their outer regions: one observable consequence of this would be a strong dependence of the structural parameters of the outer disk on the observing wavelength. To corroborate this result, we obtained surface brightness profiles using data from GALEX(UV), SDSS(optical), UKIDSS(NIR) and SPITZER-IRAC(IR). We have characterized the behaviour of the outer disk by obtaining the ratio of the inner and outer scale-lengths. Here we show the example of NGC0450. Our results suggest that there is an existing general trend of the scale-length ratio: from bluer to redder bands the scale-length ratio decreases, which is in accordance with the idea of the old smooth stellar disk in the outer disk.

The aim of this work is to investigate the possible existence of the UV-excess in the Milky Way bulge and its correlation with the presence of sdB stars in the bulge. The integrated spectrum of a bulge region from the UV to the optical was constructed. Results show that this bulge region has only a very weak UV excess

The stellar populations of 849 local infrared-selected galaxies from SDSS and IRAS (including 419 star-forming galaxies, 326 composite galaxies, 35 Seyfert 2s, and 69 LINERs in 4 spectral classes) are studied by using STARLIGHT. Among the 4 spectral classes, the importance of young populations decreases from star-forming, composite, Seyfert 2 to LINER; and Seyfert 2 and LINER are more metal-rich; ULIGs (ultra luminous infrared galaxies) & LIGs present the youngest populations among 3 infrared luminosity bins; and normal galaxies are more metal-rich. The dominant contributors to masses are all old populations.

Globular cluster (GC) systems are powerful probes to study the evolutionary histories of galaxies, being tracers of major star fomation episodes (Brodie & Strader 2006). They are found around all major galaxies and are easy to see far beyond the local group. Age dating GCs therefore helps pinpoint epochs of major star forming events. Spectroscopic age dating though (Strader et al. 2005) is extremely time consuming and can only access the few brightest clusters. An alternative is to combine near-infrared (NIR) and optical photometry, and therefore have a better chance in lifting the age metallicity degeneracy than with optical colours alone. This approach relies in testing GC colours against simple stellar population (SSP) models. The first studies following this technique showed the possible existence of a high percentage of intermediate age (2-3 Gyrs) GCs in early-type galaxies known to contain old stellar populations from integrated light studies. Two strong cases can be listed: NGC 4365 (Puzia et al. 2002, Larsen et al. 2005) and NGC 5846 (Hempel et al. 2003). In the present study we combine NIR deep photometry obtained with the WHT/LIRIS instrument and archival HST/ACS optical images to determine g(F475W), z(F840LP) and K(2.2m) magnitudes and colours of GCs in 14 early-type galaxies.

The wavelet transform acts to segregate objects in function of their size. We apply this method on images of galaxies to decompose them into coefficients representing only objects of the same size. The total fluxes of the wavelet coefficients describe the cumulative power spectrum of spatial frequencies. Based on this spectrum, we propose a new parameter to quantify the galaxy texture. As expected, it remains small and quite invariant for early-type galaxies, while it covers a large range and takes larger values for late-type galaxies. Combined with a second parameter, our determination of the texture is able to successfully separate galaxy types. By thresholding the wavelet coefficients, we detect luminous lumps. In irregular galaxies, their radial distribution seems to show a double peak. This could be the trace of a privileged radial distance of strong star formation regions.

In de la Fuente (2007; Ph. D. Thesis), the molecular clump associated with the ultracompact HII region G12.21–0.10 was confirmed as a large, hot, dense Hot Molecular Core nearby to the ionized gas. The density was confirmed by comparing low resolution NH3(2, 2) and (4, 4) VLA observations, with other molecular lines and radio–continuum observations. These results will be presented in detail in a forthcoming paper (de la Fuente et al. in preparation). In these works, for the first time, the spatial location of the Hot Molecular Core is presented. Here we present the NH3(4,4) observations from de la Fuente (2007; Ph. D. Thesis), confirming that the hotter and denser gas in the molecular core lies in a compact structure, of smaller scale than the NH3(2, 2) emission.