# Abstracts of Large Programmes scheduled in Period 91

 184.C-1143 Hainaut The Main Belt Comets (MBCs), a newly discovered class of minor bodies, display cometary activity yet are believed to have formed in the asteroid Main Belt. Confirming ice sublimation as the source of their activity will identify them as a new possible source for Earth's water. We propose a comprehensive program to fully characterize the four known MBCs using ESO and other telescopes, permitting us to understand the physical processes acting in this new class of objects, and casting light on their origin, chemistry and thermal evolution, as well as completing the census of water in the Solar System. A Discovery-class space mission proposal is being prepared, to rendezvous with and study one or more of these objects. The present program will also provide the essential data required for the preparation of navigation to the comet and orbiting around it.

 185.C-1033 Lowry The Yarkovsky-O?Keefe-Radzievskii-Paddack (YORP) effect is a torque due to both incident solar radiation pressure and the recoil effect from the anisotropic emission of thermal photons on small bodies in the solar system. It can modify their rotation rates and spin-axis orientations or obliquities. YORP can explain many observed phenomena in asteroidal science. Despite its importance there has only been three YORP detections achieved to date. We propose to use the NTT+EFOSC2 to monitor a large sample of Near-Earth Asteroids to detect the YORP effect. Such a large sample will provide valuable constraints on asteroid surface and shape evolution models as well as models of spin-orbit interactions. We will also use EFOSC2 to acquire optical spectroscopy of all targets for surface characterizations. For a selections of targets we will obtain VLT+VISIR thermal IR imaging, to constrain surface albedos, which in turn will provide more accurate shape models, critical for the YORP analysis.

 186.C-0756 Smart The discovery and subsequent detailed study of T dwarfs have provided many surprises and pushed the physics of atmospheric modeling in unpredicted directions. A critical physical quantity required to understand these objects is their distance. However, to date only 31 have published parallaxes. Here we propose the determination of T dwarf parallaxes across the full range of T sub-types, tripling the number of T dwarfs with robust distances and so providing fundamental calibrators of properties in the low-temperature substellar regime. This program will compliment the ESO2.2/WFI PARSEC program to determine parallaxes of a sample of 118 L and 22 bright T dwarfs. The areas of research directly impacted by this sample will be wide spread. On an individual object basis distances are key for assignments of binarity, metallicity and gravity and more generally the sample will provide key input for the substellar luminosity and mass functions, the connection to exo-planetary models as well as complex atmospheric processes such as non-equilibrium chemistry and turbulent mixing. Eventually these objects will provide new insights into the history of our galaxy, the kinematics of the solar neighborhood and our understanding of differing formation scenarios from stars to brown dwarfs to giant planets. In this program we will quickly exploit new T dwarfs being detected by surveys on UKIRT and VISTA -- surveys which have placed European astronomers at the forefront of the study of brown dwarfs.

 187.D-0917 Alecian Although the existence of magnetic fields in massive stars is no longer in question, our knowledge of the basic statistical properties of these fields is seriously incomplete. In particular our knowledge of the origin of the magnetic fields, the impact of these fields on massive star evolution and mass loss, and of the physics of magnetospheres is very poor. This proposal is the HarpsPol part of the MiMeS project, a consensus effort by an international team who has compiled a strategic sample of stars to address these outstanding issues. The basic aim of the programme is to exploit the unique characteristics of ESPaDOnS, Narval and HarpsPol to obtain critical missing information about the magnetic properties of massive stars, to confront current models and to guide theory. Large programmes have already been awarded on ESPaDOnS (640h) and Narval (730h). The HarpsPol observations would allow to complete the MiMeS survey in the Southern hemisphere and in particular to observe OB stars in bright open clusters that are inaccessible or challenging to observe from the north.

 188.C-0265 Melendez We propose a four year radial velocity planet search targeting 66 so-called solar twin'' stars using HARPS. We have recently shown as a result of our five-fold increase in chemical abundance accuracy that the Sun is chemically unusual compared with the majority of solar-type stars, a signature that we attribute to planet formation proceeding more efficiently in the solar system than around other stars. The proposed planet search will exploit the advantage offered by solar twins to obtain abundances of unmatched accuracy, allowing thus to study the stellar composition -- planet connection to a level that was unthinkable before. Our HARPS survey will quadruple the number of solar twins being searched for planets at high precision, illuminating the relation between chemical anomalies and planet formation in a variety of systems, ranging from stars with no planets detected in their inner regions (systems similar to our own Solar System) to stars with gas and ice giants, and probably super Earths. We are complementing the planet search by measuring with unprecedented accuracy chemical abundances for all sample stars using the 6.5m Magellan telescope. The project will ultimately yield a statistically robust sample of solar twins with homogeneous and tight constraints on both their chemical composition and planetary systems, providing novel insights on the still unknown mechanisms of planet formation.

 188.C-0779 Bouchy Transiting planets are unique among the known exoplanets in allowing direct measurements of their radius and mean density, giving fundamental insights into their interiors. The on-going \textit{CoRoT} space mission has demonstrated these last years its ability to enlarge the planet space parameters from long-period giant planets down to the Neptune and Super-Earth size planets. With its very high photometric precision and continuous observations lasting up to 5 months, it is currently detecting planet candidates with radii as small as $1.6\,R_{\earth}$ and with periods up to 100 days. In complement to the \textit{CoRoT} observations, an intensive program of ground-based spectroscopy and radial velocity observations is conducted. It is mandatory to 1) establish the planetary nature of \textit{CoRoT} transit events, 2) measure the mass of the planets and the eccentricity of their orbit, 3) determine the parameters of each host star to compute accurate planet radii, and 4) investigate the physical properties of planetary systems. The $4\times13$ HARPS nights over 4 semesters which we request in this proposal form part of the core of this program and are crucial to realize \textit{CoRoT}'s ground breaking potential.

 189.D-0165 Caffau We want to investigate directly the critical metallicity'', i.e.\ the minimum metallicity sufficient for the formation of low-mass stars. Only four of Ultra metal-poor stars are known (UMP stars with [Fe/H]$<$--4) and only about 100 extremely metal-poor stars (EMP stars with [Fe/H]$<$--3). This project has three main goals: {\bf i)~}to determine the metal-weak tail of the Halo metallicity distribution function, below [M/H]=--3.5, where the low resolution SDSS spectra are inadequate; {\bf ii)~}to determine the relative abundance of the elements in EMP-UMP stars, signature of the massive first stars. {\bf iii)~}to determine the trend of the lithium abundance in the matter at the beginning of the Galaxy. The Sloan Digital Sky Survey already gave us the chance to discover the most primordial star known to date, with $\rm [Fe/H]\approx -5$ and NO evidence of enhancement in C and N. The large number of stars observed in SDSS provides a large sample of candidates of extremely low metallicity. X-Shooter has the potentiality of performing the necessary follow-up spectroscopy providing for these stars accurate metallicities and abundance ratios for several key elements (Li, Na, Mg, Al, Ca, Ti, Cr, Sr... ) down to V$=20$.

 189.C-0313 Pontoppidan We propose a large, high-resolution (R$\sim$25,000) VISIR survey of atomic and molecular gas in the planet-forming regions of protoplanetary disks covering the range of evolutionary stages relevant for planetesimal and giant planet formation. About 55 disks have been selected from extensive spectroscopic Spitzer surveys of disks from the optically thick, strongly accreting, stage at $\sim$1 Myr to the transitional and final disk phases at $\gtrsim$5-10 Myr. The survey takes immediate advantage of an important upgrade of VISIR that will increase its observing speed by more than an order of magnitude. For the first time, we will be able to observe a statistical sample of protoplanetary disks, spanning a stellar mass range from 0.5-4.0\,$M_{\odot}$. We target the [NeII] 12.81\,$\mu$m line and rotational lines of water, OH and H$_2$ around 12.4\,$\mu$m, tracing progressively deeper layers in the protoplanetary disk surface at the planet-forming radii of 1-10 AU. The survey will produce a transformative data set designed to address the following questions concerning the evolution of planet-forming environments: (i) the timescale and mechanism for gas dissipation; (ii) the significance, chemistry and dynamics of photo-evaporative disk winds; (iii) the disk vertical thermo-chemical structure and its relation to the hardness and strength of the stellar irradiation; (iv) the nature of protoplanetary chemistry and inner disks surfaces as chemical factories.

 189.B-0925 Trager We are building a new, moderate-resolution stellar spectral library, the X-Shooter Spectral Library (XSL), for use in stellar population modelling. Stellar populations preserve the fossil record of galaxy formation and evolution. We propose here to complete our development of XSL, observing the final 418 of nearly 650 stars. X-Shooter's unique capabilities -- tremendous simultaneous wavelength coverage, and high spectral resolution -- make it possible for the first time to obtain a spectral library of observed stars covering all relevant stars needed for stellar population synthesis of external galaxies, from the ultraviolet all the way to the thermal infrared. The fact that these spectra can be obtained at a resolution of $>$8000 means that stellar population models created from XSL can be used to analyse extragalactic objects ranging from young star clusters to distant globular clusters to galaxies out to significant redshifts. XSL will provide a vital tool for extragalactic astronomers to extract even information from their observations than previously possible.

 190.C-0027 Santos The detection of extra-solar planets with masses in the super-earth and neptune mass regime represents a benchmark for planet surveys. With the number of detections growing at a steady pace, the properties and true frequency of such systems are slowly being accessed. However, due to selection biases, the frequency of neptune and super-earth planets has not been systematically probed in its whole extent. This is particularly true for the the metal-poor regime, where no specific major survey aiming at the detection of very low mass planets was carried out. Interestingly, however, planet formation models strongly suggest that neptunes and super-earths should be frequent around stars with low metallicity, contrarily to the case for giant planets. Here we propose to complete a previously started survey to test this theoretical finding, by using the HARPS spectrograph to search for very low mass exoplanets around a sample of 109 southern solar-type stars with metallicities ([Fe/H]) below $-$0.4\,dex. Results from P82, P85, and P86 revealed several very good candidates, but the available data is insufficient to allow for a confident detection. Here we aim at obtaining a number of measurements that allows us to compare the statistics of low mass planets orbiting metal-poor stars to the results from the HARPS high precision GTO program (aimed at the solar metallicity regime).

 190.D-0237 Gieren The poor knowledge about how the metallicity of classical Cepheids affects their absolute magnitudes in optical and particularly near-infrared bands has so far prevented an accurate determination of the Hubble constant by using the HST Key Project approach to build the distance ladder out to 20 Mpc with Cepheids. An accurate (1-2\%) measurement of the Hubble constant via Cepheids however is fundamental to avoid degeneracies in $H_{0}$ determinations from the cosmic microwave background. We propose an independent approach to measure the metallicity sensitivity of the Cepheid PL relation by determining accurate distances to 30 SMC Cepheids from the Infrared Surface Brightness Method. Combining the resulting absolute magnitudes of these Cepheids with those for samples of LMC and Milky Way Cepheids whose distances we have already measured in exactly the same way, we will determine the metallicity effect with very high accuracy and pave the way for a truly accurate determination of $H_{0}$ using Cepheids.

 190.C-0357 Lowry The Yarkovsky-O?Keefe-Radzievskii-Paddack (YORP) effect is a torque due to both incident solar radiation pressure and the recoil effect from the anisotropic emission of thermal photons on small bodies in the Solar System. It can modify their rotation rates and spin-axis orientations or obliquities and is a proposed mechanism for binary formation through equatorial mass loss and re-aggregation. Despite its importance there have only been three YORP detections achieved to date. This proposal is the second phase of a long-term programme (185.C-1033 and 185.C-1034) to monitor a large sample of Near-Earth Asteroids to detect the YORP effect. Such a large sample will provide valuable constraints on asteroid surface and shape evolution models as well as models of spin-orbit interactions. In semester 85 we were awarded 9 nights per semester over 8 semesters (4 years), on NTT+EFOSC2 for detection of the YORP effect from phase shifts of light curves and optical spectroscopy for surface characterizations. 103 hours were awarded over the maximum period of 4 semesters (2 years) on the VLT+VISIR for thermal infrared photometry to constrain the sizes, albedos and thermal inertias, which are required for thermophysical models to predict the strength of the YORP effect. This proposal is to continue the thermal infrared observations for the targets accessible in the second half of the overall programme.

 190.A-0685 Pentericci The long-standing quest for galaxies in the reionization epoch may be close to an end: ultra-deep IR surveys with HST, VLT and Subaru are finally providing convincing samples of z$\sim$7 candidate galaxies. We have recently spectroscopically confirmed a small sample of galaxies at z$\sim$7, providing the first possible evidence of a decrease in the transmission of Ly$\alpha$ photons compared to z$\sim$6, a predicted signature of an incomplete reionization of the Universe. To provide a definite answer on when and how reionization occurred we now propose to conduct a much larger survey over more than 200 Lyman break galaxies, selected in a homogeneous way from the superb CANDELS data-set, in 3 different fields. Spectroscopic observations will allow us to assess the continuous evolution of the Ly$\alpha$ emission over the range $6 < z < 7.3$, and determine when and how the Ly$\alpha$ started to be quenched by the neutral IGM. From a comparison to models that combine radiative transfer physics with large-scale seminumeric simulations, we will determine the neutral hydrogen fraction of the IGM that is needed to explain the observed evolution at each redshift, and we will assess if the transition to fully reionized IGM was smooth or sharp in time. The observations will also give us a first order view of the complex topology of the reionization process.

 190.C-0963 Berger Optical interferometry is a unique tool to probe the inner astronomical units of a protoplanetary disk and to shed light on the planet forming processes. In this large program, we would like to use the last year of PIONIER's life to carry the largest and most detailed survey ever of intermediate-mass young stars with astronomical unit resolution. We propose to study the innermost properties of protoplanetary disks and 1) reveal their dependance with the central star's 2) study their correlation with disk evolutionary status 3) constrain the inner disk clearing/warping related to planet formation processes 4) provide a legacy database to be exploited with future complementary observations for a unique radial probing of planet forming regions. Our strategy combines aperture synthesis, analytical and state of the art radiative transfer modelling to bring a unique, statistically significant, view on the structure of a disk inner AU. First, all the sample sources will be observed in snapshot mode to estimate first-order properties of the circumstellar emitting material. Secondly, a limited number of sources will be extensively observed and mapped with aperture synthesis techniques. These are selected based on two criteria: a)~their potential for succesful imaging; b)~the coverage of an as broad as possible a range of stellar types and evolutionary status.

 191.D-0255 Morel Massive stars are key agents in the Universe, driving the evolution of star forming galaxies through their photons, winds and violent deaths at all redshifts. The community devotes large efforts to characterize those processes which have been identified to affect the evolution of massive stars: rotation and stellar winds. Recently, important effects of magnetic fields in massive stars are suggested by observations and by models, and spectacular objects such as gamma-ray bursts and magnetars can not be understood without their consideration. But what is their frequency and field strength distribution, their origin, and what are the evolutionary consequences of magnetic fields in massive stars? We aim at directly addressing these questions through the study of a systematically selected sample of massive OB stars of different ages, considering their spin and their hard X-ray emission. We want to measure the polarization induced in spectral lines by the Zeeman effect. Recent observations showed that FORS\,2 and HARPS are ideal instrument for this. Through (funded) parallel theory projects, we aim to clarify the role of magnetic fields in the advanced stages of massive stars, including their fate as supernova or gamma-ray burst.

 191.A-0268 Adami The XXL survey, covering 50 deg$^{2}$ , is the largest deep and contiguous XMM-Newton X-ray survey to be carried out. The survey is designed to detect hundreds of galaxy clusters out to $z>1$, with a uniquely well-determined selection function. The combination of a large number of clusters with the availability of X-ray, lensing and S-Z data, will enable robust cluster mass determinations. Added to the precise knowledge of the selection function, {\bf this will provide competitive constraints on the equation of state of dark energy, many years before surveys such as LSST or EUCLID, paving the way for these later surveys}. Furthermore, we will be able to follow the physical processes involved in cluster evolution with unprecedented data quality. Cluster spectroscopic confirmation is crucial for these aims, including the determination of the cluster correlation function which contributes about one half of the dark energy constraints. {\bf We propose to achieve complete redshift measurements for the C1 cluster sample at z$\leq$1,} i.e. $\sim$240 high S/N X-ray clusters. Approximately half of these will be provided by GAMA and VIPERS. To cover the rest will use NTT/EFOSC2 ($\sim$74 z$\leq$0.6 candidates) and VLT/FORS2 ($\sim$45 0.6$\leq$z$\leq$1 candidates) over the 4 next periods. This proposal is a continuation of the current VLT/FORS2 pilot allocation (089.A-0666, cat. A).

 191.C-0505 Anglada-Escude We will obtain high-cadence observations with HARPS on a sample of M dwarfs. New data analysis techniques developed by our group and implemented in the HARPS-TERRA software, can achieve sub-m/s RV precisions on M dwarfs and enable a suit of additional new observables. This allows to investigate three fundamental aspects of low mass stars and their planetary systems in a single observational program: 1) Characterization of compact planetary systems with sub-Earth mass objects, 2) Time-resolved analysis of stellar activity and its Doppler signatures, and 3) detection of pulsations and asteroseismic studies. Compact planetary systems will be searched using high precision Doppler measurements. This program can provide the first minimum mass determinations of sub-Earth sized objects, dynamical characterization and first population studies of these peculiar systems. Time-resolved stellar activity analyses combined with wavelength dependent Doppler measurements (also enabled by HARPS-TERRA) will provide important clues to elucidate the connection between Doppler variability, activity and stellar magnetic fields. Pulsations in M dwarfs have recently been theoretical predicted but none have been yet observed. Such detection will enable the use of asteroseismic techniques on cool stars. Given this is uncharted territory, unanticipated discoveries are expected.

 191.A-0748 Ivison We have exploited the widest extragalactic {\it Herschel} imaging surveys to define a uniquely large sample of galaxies that are both faint ({\it ergo} unlensed) and extremely red ({\it ergo} rare and very distant, $z > 4$). We have begun to obtain shallow imaging of 100 of these ultra-red galaxies with LABOCA at 870\,$\mu$m (50\,hr, P90, priority A, via Max Planck). Here, we seek to exploit a representative, securely-detected subset of these SMGs to act as signposts to over-densities in the early dark matter distribution, and hence to the most distant known proto-clusters. Deeper, wider LABOCA imaging will make us sensitive to colder and/or less luminous dusty starbursts in their vicinity, and via deep FORS2 imaging and spectroscopy (of the same area) to less obscured, less dramatic, more numerous galaxy populations (LBGs). Via this comprehensive, joint approach we can determine the relative mean over-densities of their environments, which the Millennium-XXL simulation suggest is required to tell us with any certainty about the subsequent fate (mass at $z=0$) of their super-structures. We will explore 8 such environments, defining the early stages in the evolution of the most massive structures in the Universe, a key phase in their evolution that until now has only been studied in detail by modelling and theory. In total we request 46 and 34\,hr/semester with APEX and VLT, respectively, over P91--94.

 191.C-0873 Bonfils The number of planets orbiting M dwarfs increases very steeply with decreasing planetary mass or radius. At small orbital separations, M dwarfs seem to host more super-Earths than FGK stars do, and their super-Earths have a high occurence rate in the habitable zone (Bonfils et al. 2012, A\&A in press.; Howard et al. 2012, ApJS 201, 15). In that context, observing even a small sample of M dwarfs with sensitivity to Earth-mass planets on short to moderate orbital periods will give important new insight on planetary formation. {\bf We thus focus our new \textsc{Harps} Large program on the Earth-mass regime of planet formation. We propose to intensively observe 30 M dwarfs over 3.5 years}, to reach completeness: $-$ for Earth-mass planets with orbital period up to 5 days $-$ for few Earth-mass planets with orbital periods up to the outer edge of the habitable zone ($P<50$ days). In that course, we expect to detect 20$\pm$5 new super-Earths, of which ~2-3 are Earth-mass planets and 4$\pm$2 are habitable zone super-Earths, with one planet likely to transit across its star.