The surfaces of the atmosphere-less objects of our solar system are traditionally probed via reflectance measurements and/or broadband linear polarimetry. Little attention has been paid so far to the wavelength dependence of the linear polarization of the scattered light. We decided to explore the potential of spectropolarimetry as a remote sensing tool for asteroids in addition to the more traditional reflectance measurements, and we carried out a spectropolarimetric survey of asteroids – to our best knolwedge, the first of its kind. We observed a sample of asteroids of different albedo and taxonomic classes, as well as a few regions at the limb of the Moon. We show that objects exhibiting similar reflectance spectra may display totally different polarization spectra, and we suggest that both intensity and polarization spectra should be used for asteroid classification. We also found that in some cases the Umov law is violated, that is, in contrast to what is expected from simple physical considerations, the fraction of linear polarization and the reflectance spectra may be correlated positively. We conclude that future modelling attempts of the surface structure of asteroids should be aimed at explaining both reflectance and polarization spectra.

We used FORS2 in MXU mode to mimic a coarse ‘IFU’ in order to measure the 3D large-scale kinematics around the central Hydra I cluster galaxy NGC 3311. Our data show that the velocity dispersion field varies as a function of radius and azimuthal angle and violates point symmetry. Also, the velocity field shows similar dependence, hence the stellar halo of NGC 3311 is a dynamically young structure. The kinematic irregularities coincide in position with a displaced diffuse halo North-East of NGC 3311 and with tidal features of a group of disrupting dwarf galaxies. This suggests that the superposition of different velocity components is responsible for the kinematic substructure in the Hydra I cluster core.

There are several ways planets can survive the giant phase of the host star, hence one can consider the case of Earth-like planets orbiting white dwarfs. As a white dwarf cools from 6000 K to 4000 K, a planet orbiting at 0.01 AU from the star would remain in the continuous habitable zone (CHZ) for about 8 Gyr. Polarisation due to a terrestrial planet in the CHZ of a cool white dwarf (CWD) is 102 (104) times larger than it would be in the habitable zone of a typical M-dwarf (Sun-like star). Polarimetry is thus a powerful tool to detect close-in planets around white dwarfs. Multi-band polarimetry would also allow one to reveal the presence of a planet atmosphere, even providing a first characterisation. With current facilities a super-Earth-sized atmosphereless planet is detectable with polarimetry around the brightest known CWD. Planned future facilities render smaller planets detectable, in particular by increasing the instrumental sensitivity in the blue. Preliminary habitability study show also that photosynthetic processes can be sustained on Earth-like planets orbiting CWDs and that the DNA-weighted UV radiation dose for an Earth-like planet in the CHZ is less than the maxima encountered on Earth, hence white dwarfs are compatible with the persistence of complex life from the perspective of UV irradiation.

We present new, deep VLA 327 MHz, GALEX Far-UV, and Hα images of the inner ~50 kpc of Centaurus A. We find the structure identified by Morganti et al. 1999 as a possible “large scale jet” is part of a knotty, linear feature within a broader region of diffuse radio emission. The linear feature is coincident with a narrow ribbon of Far-UV and Hα emission that extends 6-35 kpc from the galaxy core, as well with a similar ridge of soft X-ray emission. The Far-UV image also shows that a strong starburst is occurring in the central dusty disk, with a star-formation rate of ~ 2M⊙ yr−1. We suggest that the various peculiar phenomena seen to the NE of the galaxy can be explained by a wind from the starburst disk, enhanced by energy input from the AGN.

In the solar neighborhood, where the typical relaxation timescale is larger than the cosmic age, at least 10% to 15% of Sun-like stars have planetary systems with Jupiter-mass planets. In contrast, dense star clusters, characterized by frequent close encounters, have been found to host very few planets. We carry out numerical simulations with different initial conditions to investigate the dynamical stability of planetary systems in star cluster environments.

Present and future large scale surveys offer promising probes of cosmology. For example the Dark Energy Survey (DES) is forecast to detect ~300 millions galaxies and thousands clusters up to redshift ~1.3. I here show ongoing work to combine two probes of large scale structure : cluster number counts and galaxy 2-point function (in real or harmonic space). The halo model (coupled to a Halo Occupation Distribution) can be used to model the cross-covariance between these probes, and I introduce a diagrammatic method to compute easily the different terms involved. Furthermore, I compute the joint non-Gaussian likelihood, using the Gram-Charlier series. Then I show how to extend the methods of Bayesian hyperparameters to Poissonian distributions, in a first step to include them in this joint likelihood.

NELIOTA is a new ESA activity launched at the National Observatory of Athens in February 2015 aiming to determine the distribution and frequency of small near-earth objects (NEOs) via lunar monitoring. The project involves upgrading the 1.2m Kryoneri telescope of the National Observatory of Athens, building a two fast-frame camera instrument, and developing a software system, which will control the telescope and the cameras, process the images and automatically detect NEO impacts. NELIOTA will provide a web-based user interface, where the impact events will be reported and made available to the scientific community and the general public. The objective of this 3.5 year activity is to design, develop and implement a highly automated lunar monitoring system, which will conduct an observing campaign for 2 years in search of NEO impact flashes on the Moon. The impact events will be verified, characterised and reported. The 1.2m telescope will be capable of detecting flashes much fainter than current, small-aperture, lunar monitoring telescopes. NELIOTA is therefore expected to characterise the frequency and distribution of NEOs weighing as little as a few grams.

This paper outlines current achievements of the Hayabusa mission and future small body missions with an emphasis on scientific prospects by both remote sensing in the vicinity of target objects and retuned sample analyses of them. First, the Hayabusa spacecraft aimed as technology demonstration for the worldfs first deep space round trip and sample return from an asteroid and it was launched via the M-V rocket in May of 2003. Soon after the touchdown on Asteroid Itokawa, a sub-km, S-type NEO in November 2005, the spacecraft lost its attitude control due to the leak of RCS propellant; the communication link was lost for 46 days. While the ion engine thrusters reached their lifetime by November of 2009 owing to either of an ion source or neutralizers at each engine, a challenging combination of the neutralizer-A with the ion source-B was devised to resume the spacecraftfs propulsion. This enabled the spacecraft to have returned to the Australian desert on the Earth in June 2010. The sample return capsule (SRC) was successfully recovered and returned to Japan for initial inspection of the Itokawa samples. After the announcement of initial sample analysis results, international announcement of sample distributions has started in the spring of 2012. Following up the original Hayabusa mission, JAXA has approved the Hayabusa-2 project in 2011, an asteroid sample return mission to 1999 JU3, a sub-km, C-type NEO aiming for 2014-5 launch, 2018-9 remote sensing including artificial impactor excavation and 2020 Earth return of both surface and sub-surface samples of the asteroid. C-type asteroid is thought to be abundant in organic matters and hydrated compound, so it has important clues to solve the origin and evolution of the life. NASAfs OSIRIS-Rex and ESAfs Marco Polo-R missions are also carbonaceous asteroid sample return missions in 2010fs-2020fs. Cometary nucleus or/and D-type asteroid sample returns like Hayabusa-Mk-II concept are natural progression of this type of the endeavor. JAXAfs solar power sail mission aims for eventual rendezvous with Jovian Trojan asteroids, reservoir of D/P-type asteroids as either leftovers of Jupiter system formation or the second generation intruders from the Kuiper belt regions.

Using data from the WISE All-Sky Survey, we have found >100 new infrared excess sources around main-sequence Hipparcos stars within 75 pc. Our empirical calibration of WISE photospheric colors and removal of non-trivial false-positive sources are responsible for the high confidence (>99.5%) of detections, while our corrections to saturated W1 and W2 photometry have for the first time allowed us to search for new infrared excess sources around bright field stars in WISE. The careful calibration and filtering of the WISE data have allowed us to probe excess fluxes down to roughly 8% of the photospheric emission at 22μm around saturated stars in WISE. We expect that the increased sensitivity of our survey will not only aid in understanding the evolution of debris disks, but will also benefit future studies using WISE.

Several observations of the central region of the Hydra I galaxy cluster point to a multi-epoch assembly history. Using our novel FORS2/VLT spectroscopic data set, we were able to map the luminosity-weighted age, [Fe/H] and [α/Fe] distributions for the stellar populations around the cD galaxy NGC 3311. Our results indicate that the stellar populations follow the trends of the photometric substructures, with distinct properties that may aid to constrain the evolutionary scenarios for the formation of the cluster core.

Debris disks are usually thought to be gas-poor, the gas being dissipated by accretion or evaporation during the protoplanetary phase. HD141569A is a 5 Myr old star harboring a famous debris disk, with multiple rings and spiral features. I present here the first PdBI maps of the 12CO(2−1), 13CO(2−1) gas and dust emission at 1.3 mm in this disk. The analysis reveals there is still a large amount of (primordial) gas extending out to 250 AU, i.e. inside the rings observed in scattered light. HD141569A is thus a hybrid disk with a huge debris component, where dust has evolved and is produced by collisions, with a large remnant reservoir of gas.

Chandra revealed cavities in the hot atmospheres of many nearby clusters. These cavities are tracers of a strong coupling between the relativistic plasma in radio sources and the cooling, thermal gas in clusters. They demonstrate clearly that the AGN affects the cooling gas that leads to star formation and galaxy growth and allow a direct measurement of the bulk of the AGN's power. Together with radio data, the cavities allow us to derive scaling relations between mechanical (cavity) and radio power that can be used to estimate the AGN feedback power when direct measurement of the cavities is not possible. We review the importance of such relations for extending current studies of feedback with new and upcoming radio telescopes such as LOFAR and SKA.

We have performed a survey of N-body simulations to explore the dynamics of primordial binaries in multiple-population globular clusters. We show that, as a consequence of the initial differences between the spatial distribution of first-generation (FG) and second-generation (SG) stars, SG binaries are disrupted more efficiently than FG binaries. The effects of dynamical evolution on the surviving binaries produces a difference between the SG and the FG binary binding energy distribution with the SG population characterized by a larger fraction of high binding energy (more bound) binaries. We also explore the evolution of the radial variation of the SG-to-FG binary number ratio and find that although the global binary fraction decreases more rapidly for the SG population, the local binary fraction measured in the cluster inner regions may still be dominated by SG binaries.

Distance measurements are currently the most powerful tool to study the expansion history of the universe without assuming its matter content nor any theory of gravitation. In general, the reconstruction of the scale factor derivatives, such as the deceleration parameter q(z), is computed using two different methods: fixing the functional form of q(z), which yields potentially biased estimates, or approximating q(z) by a piecewise nth-order polynomial function, whose variance is large. In this work, we address these two methods by reconstructing q(z) assuming only an isotropic and homogeneous universe. For this, we approximate q(z) by a piecewise cubic spline function and, then, we add to the likelihood function a penalty factor, with scatter given by σrel. This factor allows us to vary continuously between the full n knots spline, σrel → ∞, and a single linear function, σrel → 0. We estimate the coefficients of q(z) using the Monte Carlo approach, where the realizations are generated considering ΛCDM as a fiducial model. We apply this procedure in two different cases and assuming four values of σrel to find the best balance between variance and bias. First, we use only the Supernova Legacy Survey 3-year (SNLS3) sample and, in the second analysis, we combine the type Ia supernova (SNeIa) likelihood with those of baryonic acoustic oscillations (BAO) and Hubble function measurements. In both cases we fit simultaneously q(z) and 4 nuisance parameters of the supernovae, namely, the magnitudes $\mathcal{M}$1 and $\mathcal{M}$2 and the light curve parameters α and β.

Stellar magnetism, explorable via polarimetry, is a crucial driver of activity, ionization, photodissociation, chemistry and winds in stellar environments. Thus it has an important impact on the atmospheres and magnetospheres of surrounding planets. Modeling of stellar magnetic fields and their winds is extremely challenging, both from the observational and the theoretical points of view, and only recent ground breaking advances in observational instrumentation - as were discussed during this Symposium - and a deeper theoretical understanding of magnetohydrodynamic processes in stars enable us to model stellar magnetic fields and winds and the resulting influence on surrounding planets in more and more detail. We have initiated a national and international research network (NFN): ‘Pathways to Habitability - From Disks to Active Stars, Planets to Life’, to address questions on the formation and habitability of environments in young, active stellar/planetary systems. In this contribution we discuss the work we are carrying out within this project and focus on how stellar magnetic fields, their winds and the relation to stellar rotation can be assessed observationally with relevant techniques such as Zeeman Doppler Imaging (ZDI), field extrapolation and wind simulations.

We analyze the orbital distribution of objects captured to near-Earth space from the flux of comets coming from the outer Solar system. For this purpose, we use the model of the cometary cloud developed earlier (Emelfyanenko, Asher, Bailey, 2007). This model is consistent with the broad dynamical characteristics of observed near-parabolic comets, short-period comets, Centaurs and high-eccentricity trans-Neptunian objects. We show that the observed distributions of both large and small near-Earth objects are different from the modeled distribution formed dynamically by the action of planetary perturbations. In particular, while the distributions of arguments of perihelion for observed Jupiter-family comets and modeled cometary asteroids follow a sinusoidal law with pronounced maxima around 0 and 180 degrees, it is not the case for observed cometary asteroids of any size. We conclude that there exist many unobserved extinct short-period comets among near-Earth objects of various sizes.

The study objects of our work were 91 TNO with diameters greater than 200 km. On the other hand, the paper used the data for 1048 and comets with aphelion and perihelion distances Q > 30 AU and q > 0.1AU, respectively, were observed until 2012. Short-perihelion comets (sporadic and concentrated in separate groups) were excluded from the analysis. If some comet split into several parties, we have taken data for only one fragment, which is marked with the letter A. Data for comets are taken from the catalog [4] and the individual Circulars International Astronomical Union, issued in period after 2008. The data for TNO, mostly borrowed from the website [5], as well as the issues of the same circulars.

We present evolutionary models of rotating self-gravitating systems (e.g. globular clusters, galaxy cores). These models are characterized by the presence of initial axisymmetry due to rotation. Central black hole seeds are alternatively included in our models, and black hole growth due to consumption of stellar matter is simulated until the central potential dominates the kinematics in the core. Goal is to study the long-term evolution (~ Gyr) of relaxed dense stellar systems, which deviate from spherical symmetry, their morphology and final kinematics. With this purpose, we developed a 2D Fokker-Planck analytical code, which results we confirm by detailed N-Body techniques, applying a high performance code, developed for GPU machines. We compare our models to available observations of galactic rotating globular clusters, and conclude that initial rotation modifies significantly the shape and lifetime of these systems, and can not be neglected in studying the evolution of globular clusters, and the galaxy itself.

By studying the individual star-formation histories of the bulges and discs of lenticular (S0) galaxies, it is possible to build up a sequence of events that leads to the cessation of star formation and the consequent transformation from the progenitor spiral. In order to separate the bulge and disc stellar populations, we spectroscopically decomposed long-slit spectra of Virgo Cluster S0s into bulge and disc components. Analysis of the decomposed spectra shows that the most recent star formation activity in these galaxies occurred within the bulge regions, having been fuelled by residual gas from the disc. These results point towards a scenario where the star formation in the discs of spiral galaxies are quenched, followed by a final episode of star formation in the central regions from the gas that has been funnelled inwards through the disc.