The overwhelming majority of the astronomical objects are oxygen-rich, showing an abundance ratio C/O < 1 (by number). The so-called intrinsic carbon stars (C/O > 1) are formed during the AGB phase evolution of 1.5 ≤ M/M⊙≤ 3 stars through the mixing of fresh 12C from the interior of the star into the envelope during the 3rd dredge-up after each thermal pulse. They commonly show s-element enhancements produced by slow neutron captures provided by the 13C(α,n)16O reaction. The prototype of these stars are the AGB C-stars. Extrinsic carbon stars on the other hand, are formed in binary systems by mass transfer of carbon rich material from a former AGB star (now a white dwarf) onto the secondary star. Prototype of these class are the CH stars. A zoo of carbon-rich type stars exists, all being tracers of intermediate-age stellar populations. These stars are extremely useful for studies of the star formation history and chemical evolution of the galaxies. We present the detection and chemical analysis of carbon-enriched stars so far discovered within the Gaia-ESO survey. C-enriched candidates are identified from the analysis of a series of enhanced molecular features, measured through photometric and narrow-band spectroscopic filters. Then, the stellar parameters, C/O ratios and s-process element abundances are determined. The nature (intrinsic or extrinsic) of these carbon-enriched stars is discussed together with the expected impact of the Gaia mission on the knowledge of these objects in the Milky Way.

We used a large sample of FGK dwarf planet-hosting stars with stellar parameters derived in a homogeneous way from the SWEET-Cat database (Santos et al. 2013) to study the relation between stellar metallicity and position of planets in the period-mass diagram. Using this large sample we show that planets orbiting metal-poor stars have longer periods than those in metal-rich systems. This trend is valid for masses at least from ≈ 10 M⊕ to ≈ 4 MJup. Moreover, Earth-like planets orbiting metal-rich stars always show shorter periods (≤20 days) than those orbiting metal-poor stars. However, in the short-period regime there are a similar number of planets orbiting metal-poor stars. Our results suggest that the planets in the P-MP diagram are evolving differently because of a mechanism that operates over a wide range of planetary masses. This mechanism is stronger or weaker depending on the metallicity of the respective system. Most probably planets in metal-poor disks form farther out from their central star and/or they form later and do not have time to migrate as far as the planets in metal-rich systems.

Using the chemical groups identified by Mitschang et al. (2014) on a local sample of around 700 stars by Bensby et al. (2014) and the new derived ages, I report some properties on the orbital parameters (Rmin, Rmax, e, Zmax, angular momentum) and their temporal evolution. We find that the < Rmax > is nearly independent of age with values from 9 to 11 kpc, while < Rmin > shows a clear trend with age. The < e > and < Zmax > for the chemical groups clearly increase with age.

These preliminary results show a significant variety of orbits for the members inside a chemical group, that may support the idea of the identification of co-eval groups (born same time, not necessarily same place) rather than co-natal (Anguiano et al. in prep.)

Gaia, a cornerstone ESA mission, will produce a three-dimensional map of our Galaxy. It was launched in December 2013, and it is expected to provide an important improvement in our understanding of the structure, composition and evolution of the Galaxy. During its five years of data collection, Gaia is expected to transmit to Earth some 150 terabytes of raw data, producing a catalogue of some 109 individual objects. After on-ground processing the full catalogue is expected to be in the range of one to two petabytes of data. Preparation for the explotation of this huge amount of data is essential, and work is being undertaken to model the expected output of Gaia in order to predict the content of the Gaia catalogue and to facilitate the production of tools required to effectively analyse the data. Therefore, the Gaia Data Processing and Analysis Consortium (DPAC) has developed a set of simulators, including a simulator called the Gaia Object Generator (GOG), which simulates the end of mission and the epoch transit catalogues, including observational errors. In 2014, CU2 has delivered a GOG end of mission catalogue, containing the potential single star observable population (with G < 20 mag) using the Gaia Universe Model, showing the effect of the observational errors. The GOG catalogue is actively used inside CU9, which is responsible for providing access to the Gaia data to the scientific community through the Gaia archive. GOG has a direct impact in the Gaia real catalogue production, as the simulated Gaia data will be used to detect false-positives and a biased data set to validate that problems can been found. Moreover, GOG simulations will be used also to test the software which will maintain and preserve all the versions of the catalogue, and to become familiar with working with such a large and rich dataset.

In this poster we present a plan to follow-up optically early triggers from the Advanced LIGO gravitational wave detectors, which will start operating in scientific mode in the northern summer of 2015.

Our team at the University of Barcelona has contributed since the early phases of the mission to the definition, evaluation and calibration modelling of the Gaia photometry. To maximise the Gaia scientific exploitation, we have frequently shared many different tools and data with the astronomical community. Among this information we have defined several relationships among colours involving Gaia magnitudes and colours from other commonly used photometric systems (Johnson-Cousins, SDSS, Hipparcos, Tycho and 2MASS) for several types of stars (including white dwarfs). These relationships can be used for planning scientific exploitation of Gaia data, performing simulations of the Gaia-like sky, planning ground-based complementary observations and for building catalogues with auxiliary validation data. During the commissioning phase our team (as part of the Payload Experts group) has been intensively checking the first photometric data to analyse the health and properties of the real instrument. These preliminary analyses allowed us to monitor the throughput variations with time, assess the spectral resolution and re-evaluate the performances of the end-of-mission photometry. The Payload Experts group activities continue beyond the commissioning phase aiming to optimize the operations onboard for maximizing the scientific return. Some example of first spectra and photometry are shown.

Stellar clusters are crucial in the study of a variety of topics including the star formation process, stellar nucleosynthesis and evolution, dynamical interaction among stars, or the assembly and evolution of galaxies. In particular, Open Clusters (OCs) have been widely used to constrain the formation and evolution of the Milky Way disc. They provide information about the chemical patterns and the existence of radial and vertical gradients or an age-metallicity relation. However, all these investigations are hampered by the fact that only a small fraction of clusters have been studied homogeneously. Galactic surveys performed from the ground such as the Apache Point Observatory Galactic Evolution Experiment (APOGEE), the Gaia-ESO Survey (GES), or the GALactic Archaeology with HERMES (GALAH) include OCs among their targets. OCs are also sampled from the space by the Gaia and Kepler missions.

The OCCASO goal is to derive abundances for more than 20 chemical species in at least 6 Red Clump stars in ∼30 Northern hemisphere OCs. In order to ensure the reliability of the derived chemical abundances, these are derived using different analysis techniques similar to what is being performed by GES.

One of the OCCASO requirements is the homogeneity between instruments, methods and model atmospheres used, and in the same scale than the GES-UVES abundances. For this reason we are performing different tests checking internal and external consistency. Derived stellar atmosphere parameters and Fe abundances will be published in the first data release scheduled for the first semester of 2015.

The online pdf of the poster with first results is available at https://gaia.ub.edu/Twiki/pub/GREATITNFC/ProgramFinalconference/poster_OCCASO.pdf.

We report the discovery of 28 candidate high-velocity stars (HVSs) at heliocentric distances of less than 3 kpc, based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Data Release 1. All candidates have velocities, with respect to the Galactic rest frame, in excess of 300 km s−1; 12 objects move faster than 400 km s−1. Our sample of HVS candidates covers a much broader color range than the equivalent ranges discussed in previous studies and comprises the first and largest sample of HVSs in the solar neighborhood. The observed as well as the derived parameters for all candidates are sufficiently accurate to allow us to ascertain their nature as genuine HVSs, of which a subset of 12 objects represents the most promising candidates. Our results also highlight the great potential of discovering statistically large numbers of HVSs of different spectral types in LAMOST survey data. The results reported here also highlight the great potential of discovering statistically large numbers of HVSs of different spectral types in LAMOST survey data. We will continue to perform further systematic HVS searches based on the LAMOST data; the resulting stellar samples will eventually enable us to better understand the nature of the HVSs themselves and ultimately constrain the structure of the Galaxy. As a consequence, it is of great importance for investigating the various HVS ejection mechanisms, which may be more complex than previously thought.

The open cluster NGC 6791 is among the oldest, most massive open clusters in the Galaxy. High-resolution H-band spectra from the SDSS III / Apache Point Observatory Galactic Evolution Experiment (APOGEE) of 11 red giants in NGC 6791 are analyzed for their chemical abundances of 8 elements: C, N, O, Mg, Si, Ca, Ti and Fe. From the infrared spectra, this cluster is confirmed to be among the most metal-rich clusters in the Galaxy (< [Fe/H] >= 0.34 ± 0.06), and is found to have roughly solar values of the α-element abundances.

The INT Photometric H-alpha Survey (IPHAS) recently published its second data release, covering more than 1800 sq. deg. of the Galactic Plane. Its broad-band photometry has been used to produce high resolution incompleteness-corrected density maps of the Plane.

In this contributed poster we present a preliminary attempt to compute a non-axisymmetric potential together with previous axisymmetric potential of the Besançon galaxy model. The contribution by non-axisymmetric components are modeled by the superposition of inhomogeneous ellipsoids to approximate the triaxial bar and superposition of homogeneous oblate spheroids for a stellar halo, possibly triaxial. Finally, we have computed the potential and force field for these non-axisymmetric components in order to constraint the total mass of the Milky Way. We present preliminary results for the rotation curve and the contribution of the bar to it. This approach will allow future studies of dynamical constraints from comparisons of kinematical simulations with upcoming surveys such as RAVE, BRAVA, APOGEE, and GAIA in the near future. More details, are presented in https://gaia.ub.edu/Twiki/pub/GREATITNFC/ProgramFinalconference/Poster_JG.Fern%e1ndez.pdf.

The ongoing Gaia mission will undertake an astrometric, photometric and spectroscopic survey of the Galaxy. The Gaia consortium will use Gaia-only data to classify objects and to estimate their individual astrophysical parameters. However, one can achieve more reliable estimates of stellar parameters by combining Gaia data with data from other spectroscopic and photometric surveys.

The Gaia “hybrid catalog” project will provide an exquisite value-added catalogs of astrophysical parameters for Gaia targets by taking into account the “obvious” non-Gaia data (e.g., SDSS, WISE, Pan-STARRS, APOGEE, PPMXL, SDSS, 2MASS, Tycho). By including spectroscopic indicators of metallicity when available, or infrared photometry, we can reduce the degeneracies between extinction and temperature and improve the estimation of metallicity and surface gravity.

However, the creation of such catalogs comes with significant challenges. First the cross-matching of catalogs with various selection functions, or photometric depths. Second, we must optimize the data analysis to produce the most accurate information given a specific science goal. Finally, the construction of such catalogs will require significant computation power. The current plan is to do this using the local resources at the Max-Planck-Institut für Astronomie, and then each catalog will go through validation and integration processes to finally be released as part of the value-added Gaia data products. From these challenges, it is clear that hybrid catalogs will not be a copy of the Gaia catalog but must be adapted to support very specific science questions.

In the poster we presented, we details in particular two applicationsof the Gaia hybrid catalogs. First, we considered the addition of WISEdata to the Gaia information. The WISE data enable us to constrainnot only the amount of extinction through the addition of infrareddata, but also allow us to better classify certain spectral types. Forinstance, from the addition of the WISE filters, one can select theOxygen-rich Asymptotic Giant Branch (AGBs) stars to find spatialsubstructures with particular interstellar medium properties. Breaking through the distance-extinction degeneracies will also help finding largescale structures in the disk such as streams or spiral arms, especiallywhen combined with age or metallicity selections for instance.

Second, we presented one aspect of the hybrid catalogs dedicatedto support the analysis of star clusters. Star clusters are not onlycalibrators of stellar evolution models but also references to study starformation in general. We presented one future outcome of the hybridcatalogs, in which we provide for known star clusters, an assessment ofstellar memberships based on a combination of phase-space, and colormagnitudedistribution fitting. In this application, the assumption thata cluster is a “simple” population provides a significant advantage whenderiving individual star properties. Eventually one can imagine thisapplication can be extended to stellar streams.

Hybrid catalogs are meant to be provided along with the Gaia datareleases, and will offer a tremendous source of validation for the GaiaData Processing.

We present a method for knowledge analysis in large astronomical spectrophotometric archives. The method is based on a type of unsupervised learning Artificial Neural Networks named Self-organizing maps (SOMs). SOMs are used to organize the information in clusters of objects, as homogeneously as possible according to their spectral energy distributions, and to project them onto a 2D grid where the data structure can be visualized.

Our algorithm has been tested by means of simulated Gaia spectrophotometry (150,000 objects), which is based on SDSS observations and theoretical spectral libraries covering a wide sample of astronomical objects. We demonstrate the usefulness of the method by analyzing over 10,000 objects, mostly fainted objects and unsuccessful observations, that were rejected by the SDSS spectroscopic classification pipeline and thus classified as “UNKNOWN”. This dataset was transformed to Gaia BP and RP format by the use of GOG simulator.

GUASOM provides a useful toolbox to study the data distribution in extense archives. Even more, the discovered neighbourhood relationships help to unveil the physical nature of objects never observed before. To this effect, we used the SIMBAD catalog to perform crossmatching with the SDSS astrometry, seeking for more identifications.

Various Galactic stellar spectroscopic surveys are currently underway, and each is expected to achieve high internal accuracy in terms of stellar parameters and abundances. A number of questions related to the formation and evolution of the Galaxy may be addressed based on samples of stars observed within each survey. In addition, complementary samples of stars may be constructed by combining data from different surveys. The Gaia FGK Benchmark Stars provide the necessary link to bring the quantities measured from different spectra with different methods onto the same scale. We selected 28 FGK stars and 5 M giants with available angular diameter θ, bolometric flux Fbol, and distance. We used the fundamental relation Teff ∝ F/θ0.5 to determine a reference effective temperature. We used the fundamental relation g ∝ M/R2, where M is the mass and R the radius, to determine a reference surface gravity. A homogeneous analysis of a high resolution and high signal-to-noise spectral library provides a reference metallicity (Blanco-Cuaresma et al. 2014A&A...566A..98B, Jofré et al. 2014A&A...564A.133J). These stars serve as a reference for testing and homogenizing large stellar surveys such as the Gaia mission and the Gaia-ESO public spectroscopic survey and for improving models of FGK-star atmospheres. A detailed discussion of the fundamental Teff and logg values will be presented in Heiter et al. (to be submitted).

We have proposed a low Galactic latitude disk survey plan concentrating on open clusters (Chen, Hou et al. 2012) in the LAMOST main survey. We expect to cover more than 400 open clusters in the low Galactic latitude region, and obtain stellar radial velocities as well as abundance information for stars faint as r=16 mag in the cluster fields.

We use variable AGB carbon stars, in the Catalina Surveys, to probe the tidal arms of the Sgr dSph.

We present preliminary results of the temporal variability of the interstellar extinction in the line of sight of NGC 4833. We detected 10 stars which could vary according to a variation of the reddening.

Solar twins are stars that replicate the solar astrophysical properties. They represent natural candidates for harboring planetary systems similar to ours. Solar siblings are stars which were born in the same cluster than the Sun. They may differ from the Sun by their mass and radius, but they have the same age, the same chemical composition, and similar spatial velocities. Solar twins and siblings may have formed in the same conditions as the Sun, and thus they may give some clues on where and how the Sun formed in our Galaxy. In this study, we search the closest solar twins among thousands of solar type stars observed at high spectral resolution over the full optical range. The spectra are directly compared to solar ones observed by reflection on asteroids or the Moon with the same instrument. This purely differential method, based on the reduced χ2, is independant of any model. We applied it to a selection of ∼17700 spectra of ∼3500 different stars from the ELODIE archive. The star HD 146233 (18 Sco) keeps its status of the closest solar twin. The second closest star is the known solar twin HD 138573. Some other stars among the top twenty best stars have never been studied before, like HD 168009, HD 056124, and HD 029150. Atmospheric parameters of the top twenty solar twins were determined with the iSpec code. Their effective temperatures and gravities are found to be within 100 K and 0.1 dex from those of the Sun, respectively. We find the metallicity of the twins to be higher by 0.05 dex on average than that of the Sun. We derived the chemical abundances for the 200 closest solar twins in a line by line differential basis relative to the Sun. The absorption lines used in this study come from a rigorous analysis of 670 lines measured in our 14 solar spectra. We find several stars with all abundances within 0.01 dex from those of the Sun. Several of them fall on the Yonsei-Yale theoritical isochrone of solar age and metallicity. Thus they could have been formed in the same cluster as the Sun.

We present a technique to detect Ultra-Faint Dwarf Galaxies (UFDs) in the Galactic Halo, using sky and proper motion information.The method uses wavelet transforms to detect peaks in the sky and proper motion planes, and to evaluate the probability of these being stochastic fluctuations. We aim to map thoroughly the detection limits of this technique. For this, we have produced a library of 15,000 synthetic UFDs, embedded in the Gaia Universe Model Snapshot (GUMS) background (Robin et al. 2012), each at a different distance, different luminosity, half-light radius, velocity dispersion and center-of-mass velocity, varying in ranges that extend well beyond those spanned by known classical and ultra-faint dSphs. We use these synthetic UFDs as a benchmark to characterize the completeness and detection limits of our technique, and present our results as a function of different physical and observable parameters of the UFDs (see full poster for more details at https://gaia.ub.edu/Twiki/pub/GREATITNFC/ProgramFinalconference/Poster_UFGX_Bcn_C_Mateu.pdf).

Aims. To constrain the Initial Mass Function (IMF) of the Galactic young (<1 Gyr) thin Disc population using Cepheids.

Methods. We have optimized the flexibility of the new Besançon Galaxy Model (Czekaj 2014) to simulate magnitude and distance complete samples of young intermediate mass stars assuming different IMFs and Star Formation Histories (SFH). Comparing the simulated synthetic catalogues with the observational data we studied which IMF reproduces better the observational number of Cepheids in the Galactic thin Disc. We analysed three different IMF: (1) Salpeter, (2) Kroupa-Haywood and (3) Haywood-Robin IMFs with a decreasing SFH from Aumer & Binney (2009).

Results. For the first time the Besançon Galaxy Model is used to characterize the galactic Cepheids. We found that for most of the cases the Salpeter IMF overestimates the number of observed Cepheids and Haywood-Robin IMF underestimates it. The Kroupa-Haywood IMF, with a slope α = 3.2, is the one that best reproduces the observed Cepheids. From the comparison of the predicted and observed number of Cepheids up to V = 12, we point that the model might underestimate the scale height of the young population.

Conclusions. In agreement with Kroupa & Weidner (2003) our study shows that the Salpeter IMF (α = 2.35) overestimates the star counts in the range 4 ≤ M/M⊙≤ 10 and supports the idea that the slope of the intermediate and massive stars IMF is steeper than the Salpeter IMF.

The poster can be found online at: https://gaia.ub.edu/Twiki/pub/GREATITNFC/ProgramFinalconference/Poster_R._Mor_Great.pdf.