Recent Talks

En esta charla se presenta una puesta al día de los resultados más importantes de un estudio arqueoastronómico interdisciplinar realizado en varias decenas de yacimientos arqueológicos de las culturas ibérica y tartesia del primer milenio a.C. en el levante y sur peninsular. En el caso de los templos tartésicos, posiblemente muy influidos o construidos por colonos fenicios, muestran un patrón de orientación muy bien definido que podría estar relacionado con el ocaso más meridional de Venus y, posiblemente, con el culto a la diosa fenicia Astarté, asociada a dicho planeta según los historiadores de la antigüedad. Por otra parte, encontramos que una fracción importante de los santuarios ibéricos estudiados, todos ellos dedicados a una diosa femenina, muestran marcadores del orto u ocaso solar sobre elementos destacados del horizonte en los equinoccios o una fecha muy cercana a estos, posiblemente el punto medio temporal entre solsticios. Esta relación astronómica equinoccial, la más clara de todas las encontradas en el mundo ibérico, sugiere la existencia de ritos asociados a la estacionalidad, festividades agrarias de la fecundidad similares a otras bien conocidas del Mediterráneo antiguo. La cronología más temprana de los santuarios relacionados con los equinoccios indican que comenzaron a funcionar alrededor de mediados del siglo IV a.C., momento de cambios importantes en la ideología de la sociedad ibérica y de un incremento de la influencia cartaginesa en la zona.

The Magellanic Clouds are the closest star forming galaxies, and their star formation histories can be derived in great details from color-magnitude diagrams reaching the oldest main sequence turnoffs. In the last several years, we have been conducting a wide research program on the Magellanic Clouds, including both photometry and spectroscopy, and have analysed the star formation history across both the Large and the Small Magellanic Clouds. This has revealed the nature of the stellar population gradients of these galaxies, as well as signatures that can possibly be related to their interaction history, among them and with the Milky Way.

This paper discusses how cosmic gas accretion controls star formation, and summarizes the physical properties expected for the cosmic gas accreted by galaxies. The paper also collects observational evidence for gas accretion sustaining star formation. It reviews evidence inferred from neutral and ionized hydrogen, as well as from stars. A number of properties characterizing large samples of star-forming galaxies can be explained by metal-poor gas accretion, in particular, the relationship between stellar mass, metallicity, and star formation rate (the so-called fundamental metallicity relationship). They are put forward and analyzed. Theory predicts gas accretion to be particularly important at high redshift, so indications based on distant objects are reviewed, including the global star formation history of the universe, and the gas around galaxies as inferred from absorption features in the spectra of background sources.

Different components of galaxies are the result of internal and environmental processes during their lifetimes. Disentangling these processes is an important issue for understanding how galaxies form and evolve. In this context isolated galaxies provide a fruitful sample for exploring galaxies which have evolved mainly by internal processes (minimal merger/accretion/tidal effects). I will present the structural analysis performed as part of the AMIGA (Analysis of the interstellar Medium of Isolated GAlaxies; http://www.amiga.iaa.es) project. The analysis of the stellar mass-size relation of our spiral galaxies reveals a larger size for disks in low-density environments, as well as a dependence of disk size on the number of satellites. A 2D bulge/disk/bar decomposition of SDSS i-band images was performed in order to identify the pseudobulges in our sample. We derived (g-i) bulge colors and find a large fraction of pseudobulges in the red sequence of early-type galaxies. The bluer pseudobulges in our sample tend to be located in those galaxies more affected by tidal interactions. The properties of the majority of bulges in isolated galaxies suggest that pseudobulges formed most of their mass at an early epoch, and that specific environmental events may rejuvenate pseudobulges.

Evolved stars are factories of cosmic dust. This dust is made of tiny grains that are injected into the interstellar medium and plays a key role in the evolution of astronomical objects from galaxies to the embryos of planets. However, the processes involved in dust formation and evolution are still a mystery. The increased angular resolution of the new generation of telescopes will provide for the first time a detailed view of the conditions in the dust formation zone of evolved stars, as shown by our first observations with ALMA. The aim of the NANOCOSMOS project is to take advantage of these new observational capabilities to change our view on the origin and evolution of dust. We will combine astronomical observations, modelling, and top-level experiments to produce stardust analogues in the laboratory and identify the key species and steps that govern the formation of these nanoparticles. We will build two innovative setups: the Stardust chamber to simulate dust formation in the atmosphere of evolved stars, and the gas evolution chamber to identify novel molecules in the dust formation zone. We will also improve existing laboratory setups and combine different techniques to achieve original studies on individual nanoparticles, their processing to produce complex polycyclic aromatic hydrocarbons, the chemical evolution of their precursors and their reactivity with abundant astronomical molecules. Our simulation chambers will be equipped with state-of-the-art in situ and ex situ diagnostics. Our astrophysical models, improved by the interplay between observations and laboratory studies, will provide powerful tools for the analysis of the wealth of data provided by the new generation of telescopes.

The synergy in NANOCOSMOS between astronomers, vacuum and microwave engineers, molecular and plasma physicists, surface scientists, including both experimentalists and theoreticians is the key to provide a cutting-edge view of cosmic dust.

One of the most widely researched topics in Extragalactic Astrophysics
in the last decades is how early-type galaxies have formed their stars
and assembled. In this context, we now have unequivocal observational
evidences about the existence of a numerous population of massive
galaxies which not only had assembled a considerable amount of stars
(~10^{^11} M_sun) by z~2, but were already evolving passively by that
time. These galaxies, the likely progenitors of nearby ellipticals,
are also quite compact in comparison with local galaxies of the same
mass. These result are mainly based on measurements designed to obtain
stellar masses and sizes, and our estimations of these parameters are
now quite robust. Now we need a more secure determination of how
exactly they formed and assembled their stellar mass in just 2-3 Gyr
(z>2). In other words, how was their Star Formation History and which
are the properties (age, metallicity, dust content) of their stellar
populations? And how could they end up with such high masses and small
sizes? In this talk, we will present our results about the SFH (mainly
ages and duty cycles) of massive galaxies at z=1-3 based on the
deepest spectro-photometric data ever taken. These data were gathered
by the Survey for High-z Absorption Red and Dead Sources (SHARDS), a
ESO/GTC Large Program aimed at obtaining R~50 optical spectra of
distant galaxies. This resolution is especially suited to measure
absorption indices such as D(4000), Mg_UV, the Balmer break,etc.. for
galaxies up to z~3 (merging our SHARDS data with HST/WFC3 grism
observations) or emission-line fluxes for faint targets up to
z~6. These measurements represent a big step forward for the robust
determination of the stellar population properties, providing a much
more certain characterization of the stellar content of distant
galaxies than the typical broad-band studies. Our results uniquely
allow to study the stellar content of red and dead galaxies at z~2 and
identify progenitors at higher redshifts, as well as helping to
constrain the models of galaxy formation.

Most massive galaxies have supermassive black holes at their centres, and the masses of the black holes correlate with properties of the host-galaxy bulge component. These empirical scaling relations are important for distinguishing between various theoretical models of galaxy evolution, and they furthermore form the basis for all black-hole mass measurements at large distances. Observations have shown that the mass of the black hole is typically 0.1 per cent of the mass of the stellar bulge of the galaxy. Our spectroscopic survey with the Hobby-Eberly Telescope of 1000 nearby galaxies revealed several compact lenticular galaxies with extremely high velocity dispersions. The first example is NGC1277, which is a small, Re=1kpc, compact, lenticular galaxy with a mass of 1.2×10^11 solar masses. From the stellar kinematics we determined that the mass of the central black hole is 10^10 solar masses, more than 10 per cent of its bulge mass. I will present HST images and IFU spectroscopy of a dozen more compact galaxies that all appear to host extremely big black holes and have Salpeter-like IMFs. These local systems, with distances less than 100 Mpc, could be the passively evolved descendents of the quiescent compact nugget galaxies found at z~2 and the >10e9 Msun quasars that are found at z>6.

ESO is an intergovernmental organization for astronomy founded in 1962 by five countries. It currently has 14 Member States in Europe with Brazil poised to join as soon as the Accession Agreement has been ratified. Together these countries represent approximately 30 percent of the world’s astronomers. ESO operates optical/infrared observatories on La Silla and Paranal in Chile, partners in the sub-millimeter radio observatories APEX and ALMA on Chajnantor and is about to start construction of the Extremely Large Telescope on Armazones.

La Silla hosts various robotic telescopes and experiments as well as the NTT and the venerable 3.6m telescope. The former had a key role in the discovery of the accelerating expansion of the Universe and the latter hosts the ultra-stable spectrograph HARPS which is responsible for the discovery of nearly two-thirds of all confirmed exoplanets with masses below that of Neptune. On Paranal the four 8.2m units of the Very Large Telescope, the Interferometer and the survey telescopes VISTA and VST together constitute an integrated system which supports 16 powerful facility instruments, including adaptive-optics-assisted imagers and integral-field spectrographs, with half a dozen more on the way and the Extremely Large Telescope with its suite of instruments to be added to this system in about ten years time. Scientific highlights include the characterisation of the supermassive black hole in the Galactic Centre, the first image of an exoplanet, studies of gamma-ray bursts enabled by the Rapid Response Mode and milliarcsec imaging of evolved stars and active galactic nuclei. The single dish APEX antenna, equipped with spectrometers and wide-field cameras, contributes strongly to the study of high-redshift galaxies and of star- and planet-formation. Early Science results obtained with the ALMA interferometer already demonstrate its tremendous potential for observations of the cold Universe.

The application of the Fourier transform (FT) technique to high resolution spectra of OB-type stars has challenged our previous knowledge about stellar rotation in stars in the upper region of the HRD. The FT is an old and powerful tool that has being widely used in the case of cool stars, but only very recently applied to massive stars in a systematic way. In this talk I will present the results of the line-broadening characterization of ~250 Galactic OB-type stars (including dwarfs, giants and supergiants with spectral types O4-B9) from the IACOB spectroscopic database. I will show how these analyses have led to a downward revision of previously determined projected rotational velocities in these stars, and have definitely confirmed the presence of a non-negligible extra line-broadening contribution (commonly called macroturbulent broadening) in the whole OB star domain. I will also provide some notes about the importance of these findings on the evolution of massive stars and the detection of stellar oscillations along the lifetime of these important astrophysical objects.

MUSE (Multi Unit Spectroscopic Explorer) is a 2nd generation Integral Field facility for the VLT. With a field of view of 1x1 arcmin, fine sampling, intermediate spectral resolution and large spectral coverage in the visible, it uses a complex image slicer, twenty-four parallel spectrographs and a large detector area. In addition, MUSE is conceived to work assisted by the Adaptive Optics Facility (AOF), which will enhance notably its performance. MUSE is the result of ten years of design and development by the MUSE consortium — headed by the Centre de Recherche Astrophysique de Lyon, France and the partner institutes Leibniz-Institut für Astrophysik Potsdam (AIP, Germany),  Institut für Astrophysik Göttingen (IAG, Germany),  Institute for Astronomy ETH Zurich (Switzerland), L'Institut de Recherche en Astrophysique et Planétologie (IRAP, France), Nederlandse Onderzoekschool voor de Astronomie (NOVA, the Netherlands) and ESO.
MUSE has been successfully installed on ESO’s Very Large Telescope (VLT). In this talk it will be presented the instrument, its design and challenges, the integration (both in Europe and Paranal), the first light and first commissioning results.