Talks

I will provide an overview of the Gaia mission and its first data release (Gaia DR1), followed by a summary of the scientific highlights achieved since the publication of Gaia DR1. I close with a look ahead at the second Gaia data release and the longer term future of space astrometry.

Looking to the stars has always been appealing to mankind, its encompassing mysteries, the beauty of the unknown. As science evolve our understanding of our surrounding Universe grows bigger and we quickly understand that the unknown is even bigger than we previously thought. On a counter wave, lack of interest about science is growing, in particular in developed countries. Awareness about our place in the cosmos or simple concepts as why do we have seasons and the scales in the Universe is not known by so many people. Astronomy is a science that can gracefully be used as a cross-disciplinary tool to teach all STEAM subjects (Science, technology, engineering, arts and mathematics) and can also act as a hub to reunite many different fields of work. The IAU has been playing an important role in the increase of astronomy awareness with initiatives like the International Year of Astronomy in 2009 and its decadal strategic plan that is now under discussion to be renewed. Programs devoted to astronomy education such as the Galileo Teacher Training Program, a cornerstone of IYA2009 and a living legacy or the Office of Astronomy for Development efforts will be presented during this event. Funding opportunities and their role for the growth of science literacy and research will also be discussed, with the presentation of projects funded by the European Commission and the reach they can have via the established and already mentioned networks. Cutting edge science education projects such as Go-Lab, Inspiring Science Education, European Hands-on Universe among others will be also presented as good examples.

Hundreds of exoplanets have been detected using the Doppler technique over the past two decades and ground-based photometry together with the NASA Kepler mission have discovered thousands of transiting planets, providing important statistical information about the size and ubiquity of other worlds. However, the vast majority of planets around nearby stars have escaped detection because a radial velocity precision approaching 10 cm/s is required to discover potentially habitable worlds and to unravel complex multi-planet architectures. Such high precision, if possible, would also dramatically improve the efficiency of space-based transit missions by providing the masses needed to estimate bulk densities and model the internal structure of exoplanets. Indeed, the future of exoplanet science has very different trajectories depending on the precision that can ultimately be achieved with Doppler measurements. I will describe our path toward 10 cm/s radial velocity precision and the EXPRES instrument that we will commission at the Discovery Channel Telescope (DCT) in October 2017 to carry out this experiment. The DCT is a near twin of the SOAR telescope and replicating this instrument as SORCERESS for the southern hemisphere would provide exciting capability.

In this talk I will give a comprehensive overview of the current status of the Spanish Astronomical Society (SEA). Our Society was founded on 1991 thus it is a young society with more than 750 professional astronomers that celebrates its twenty-fifth anniversary this year. This is an excellent opportunity for us to evaluate the past and ongoing efforts and to prepare for the new challenges. I will talk on what we have achieved, among other the experience of joining ESO around 10 years ago, and also on the main scientific programs ongoing among our institutes. I will also comment on some efforts of our executive committee focused on improving the professional development of our members as well as enhance the international collaboration with other astronomical societies.

Dwarf galaxies are the most common type of galaxy in the Universe and include the most dark-matter-dominated objects known. They offer intriguing insights into evolutionary processes at low halo masses and low metallicities. Moreover, as survivors of a once much more numerous population of building blocks of larger galaxies, they are key to understanding very early star formation processes. The Local Group and particularly the Milky Way’s dwarf galaxy entourage offer us the unique possibility to compare in detail dwarf and Galactic populations. This is an important step towards quantifying the magnitude and time scales of dwarf contributions to the build-up of the Milky Way and allows us to test predictions of cosmological theories and hierarchical structure formation.

Precision measurements across cosmic time have led to a widely accepted cosmological paradigm for galaxy assembly and evolution, the cold dark matter (ΛCDM) model. Although this theory has had great success in explaining the observed large-scale distribution of mass in the universe, the nature of the dark matter particle is best tested on small scales, where its physical characteristics manifest themselves by modifying the structure of galaxy halos and their lumpiness. It is on these scale that detailed comparisons between observations and theory have revealed several discrepancies and challenged our understanding of the mapping between dark matter halos and their baryonic components. In this talk I will review the triumphs and tribulations of the theory. While the latter may indicate the need for more complex physics in the dark sector itself, emerging evidence suggests that a poor understanding of the baryonic processes involved in galaxy formation may be at the origin of these controversies.

Observations of the very large galaxy sample from the SDSS Main Galaxy Survey indicate that galaxy properties at given stellar mass are bimodal in morphology, color, and fertility to star formation (star formation rate to stellar mass ratio). I will review the physical processes (both internal and external) affecting fertility and observational studies of how fertility scales with environment. The measure of environment from redshift space galaxy catalogs is intrinsically difficult and I will describe basic group finders and test their accuracies on mock galaxy catalogs. This leads to the following questions: 1) Do environmental effects strongly depend on group finder? 2) Do perfect group finders bias our understanding of environmental effects? 3) Do numerical models of galaxy formation reproduce the correct environmental effects? 4) How far do galaxies feel their environment and what are the physical processes at work? 5) At what orbital phase in their groups/clusters is the fertility of galaxies quenched and what does this teach us on the physical processes at work?

In this presentation the concept of regular black holes will be reviewed and, in particular, that described by the Hayward metric. The general physical properties of these objects will be discussed as well as the associated thermodynamic quantities. Finally, it will be conjectured a scenario in which critical (and stable) regular black holes could play the role of dark matter.

In recent years there have been significant advances that allowed us to fine-tune our understanding of the stellar content of massive ETGs. This has been possible by means of detailed spectroscopic studies of newly acquired high quality data, both long-slit and IFU, and recent developments in stellar population modeling and fitting algorithms. I will show how the stellar populations are disentangled with unprecedented detail, which from larger scales to small ones include i) varying stellar components that contribute to the integrated light, ii) the mass distribution of individual stars, i.e. the IMF, and iii) detailed element abundances in the stars. Extending the spectral range from the UV to the Near-IR, allows us to obtain well constrained solutions that point to the presence of tiny mass fractions of young stellar components in most massive ETGs, which are compatible with residual SF. The distribution of stellar masses is tackled by means of IMF-sensitive line strength indices, both in the optical and in the Near-IR, revealing a dwarf-dominated IMF shape in the central regions of most massive ETGs. Finally, well selected line strength indices as well as full spectrum fitting reveal that not only Mg but also other elements, such as Na, deviate from the scaled-solar abundance pattern of the bulk of the stars that constitute these galaxies.