The Gaia spectrophotometric standard stars survey -II. Instrumental effects of six ground-based observing campaigns

The Gaia SpectroPhotometric Standard Stars (SPSS) survey started in 2006, it was awarded almost 450 observing nights, and accumulated almost 100,000 raw data frames, with both photometric and spectroscopic observations. Such large observational effort requires careful, homogeneous, and automated data reduction and quality control procedures. In this paper, we quantitatively evaluate instrumental effects that might have a significant (i.e.,$\geq$1%) impact on the Gaia SPSS flux calibration. The measurements involve six different instruments, monitored over the eight years of observations dedicated to the Gaia flux standards campaigns: DOLORES@TNG in La Palma, EFOSC2@NTT and ROSS@REM in La Silla, [email protected] in Calar Alto, BFOSC@Cassini in Loiano, and [email protected] in San Pedro Martir. We examine and quantitatively evaluate the following effects: CCD linearity and shutter times, calibration frames stability, lamp flexures, second order contamination, light polarization, and fringing. We present methods to correct for the relevant effects, which can be applied to a wide range of observational projects at similar instruments.Comment: 16 pages, 13 figures, accepted for publication in Astron. Nach

Language re-discovered: A death education intervention in the net between kindergarten, family and territory

The article presents the positive results of a death education experience, realized owing to a collaboration between school, family and territory. The project, with the scope of reflecting on topics of death and spirituality, included 46 children of 5 from kindergarten and 50 parents, and then mobilizing the entire community. Social services and public administration had a special role in this, aiming to guarantee the necessary support for the families in the existential reflections. The experience was monitored with participatory observation, via interviews and questionnaires. The children answered questions regarding death and spirituality during an open and sincere conversation with the teachers. The parents, who at home talked about certain pre-defined teams with the children, were asked to give their informed consent and were given a questionnaire with open questions ex-ante/ ex-post. All data were processed via qualitative analysis of the texts. The results are truly positive, showing that children are capable of facing the problem of death and are able to acquire a certain representation of the spiritual dimension. The parents, who in the beginning demonstrated some anxiety, eventually were greatly satisfied and expressed their willingness to continue to search for the connection between death and transcendence

Estudio arqueométrico y evaluación del deterioro de los materiales cerámicos de la fachada de la iglesia de Santa Maria del Carmine (Pavía, Italia)

We performed an archaeometric study of the ceramic materials from the façade of the church of Santa Maria del Carmine in Pavia (Italy). We obtained useful information about the firing temperatures, the provenance of raw materials and the type of oven used. The ceramics used in the façade are mineralogically rich in quartz, feldspar and phyllosilicates, and newly formed calcium silicate phases were detected in some samples. Microtextural observations revealed the presence of incipient reaction rims, phyllosilicate sintering and partial vitrification of the matrix. Ceramics show high porosity (32 to 45%) and pore sizes of between 0.4 and 1.3 µm. Our study of the different types of decay collected on the façade of the church (green and black patinas and efflorescences) revealed the presence of gypsum, whewellite, thenardite and moolooite

Identification and characterization of Vitis vinifera subsp sylvestris populations in north-western Italy

The Italian peninsula, for its favorable environmental and geo-morphological conditions, can be considered an ultimate area for survival and development of Vitis vinifera subsp. sylvestris (Gmelin) Hegi, even though severely affected by human impact. Large surveys started in early 1990 throughout the country. At the time few regions, like Piedmont located in the north-west of the country, were considered lacking of wild vinifera. More recent prospection started several years ago, leading to the discovering of five vinifera sylvestris populations plus other sites with few individuals. The sites of discovery were described for their ecological features and the identified plants were referenced and characterized by morphology (18 descriptors from the OIV list) and genetics (14 n-SSR loci). The esteemed consistency of each population ranged from 20 to 150 individuals. Morphological and biological traits (dioecious plants, females producing very small roundish black berries), as well as genetic profiles, indicated the observed plants are true vinifera sylvestris. As to the ecological requirements, plants were confirmed to be highly dependent on water availability into the soil. The neighbor-joining (NJ) dendrogram resulting from SSR allelic pattern of the individuals belonging to the five populations and to one location with isolated plants, indicated population's genetic similarity broadly reflects site's geographic distance. Considering the numerous reports in the past, spreading and consistency of wild grape germplasm from the region of Piedmont severely decreased over a period of 100-150 years. The relative short distance from wild population's sites and vineyards must also be regarded as a worrying condition because of contamination risks. All means to avoid the loss of this native Vitis germplasm must be undertaken by protection policy and proper land management

Studying the evolution of large-scale structure with the VIMOS-VLT Deep Survey

The VIMOS-VLT Deep Survey (VVDS) currently offers a unique combination of depth, angular size and number of measured galaxies among surveys of the distant Universe: ~ 11,000 spectra over 0.5 deg2 to I_{AB}=24 (VVDS-Deep), 35,000 spectra over ~ 7 deg2 to I_{AB}=22.5 (VVDS-Wide). The current ``First Epoch'' data from VVDS-Deep already allow investigations of galaxy clustering and its dependence on galaxy properties to be extended to redshifts ~1.2-1.5, in addition to measuring accurately evolution in the properties of galaxies up to z~4. This paper concentrates on the main results obtained so far on galaxy clustering. Overall, L* galaxies at z~ 1.5 show a correlation length r_0=3.6\pm 0.7. As a consequence, the linear galaxy bias at fixed luminosity rises over the same range from the value b~1 measured locally, to b=1.5 +/- 0.1. The interplay of galaxy and structure evolution in producing this observation is discussed in some detail. Galaxy clustering is found to depend on galaxy luminosity also at z~ 1, but luminous galaxies at this redshift show a significantly steeper small-scale correlation function than their z=0 counterparts. Finally, red galaxies remain more clustered than blue galaxies out to similar redshifts, with a nearly constant relative bias among the two classes, b_{rel}~1.4, despite the rather dramatic evolution of the color-density relation over the same redshift range.Comment: 14 pages. Extended, combined version of two invited review papers presented at: 1) XXVIth Astrophysics Moriond Meeting: "From Dark Halos to Light", March 2006, proc. edited by L.Tresse, S. Maurogordato and J. Tran Thanh Van (Editions Frontieres); 2) Vulcano Workshop 2006 "Frontier Objects in Astrophysics and Particle Physics", May 2006, proc. edited by F. Giovannelli & G. Mannocchi, Italian Physical Society (Editrice Compositori, Bologna

Geometrical tests of cosmological models. III. The cosmology-evolution diagram at z=1

The rotational velocity of distant galaxies, when interpreted as a size (luminosity) indicator, may be used as a tool to select high redshift standard rods (candles) and probe world models and galaxy evolution via the classical angular diameter-redshift or Hubble diagram tests. We implement the proposed testing strategy using a sample of 30 rotators spanning the redshift range 0.2<z<1 with high resolution spectra and images obtained by the VIMOS/VLT Deep Redshift Survey (VVDS) and the Great Observatories Origins Deep Survey (GOODs). We show that by applying at the same time the angular diameter-redshift and Hubble diagrams to the same sample of objects (i.e. velocity selected galactic discs) one can derive a characteristic chart, the cosmology-evolution diagram, mapping the relation between global cosmological parameters and local structural parameters of discs such as size and luminosity. This chart allows to put constraints on cosmological parameters when general prior information about discs evolution is available. In particular, by assuming that equally rotating large discs cannot be less luminous at z=1 than at present (M(z=1) < M(0)), we find that a flat matter dominated cosmology (Omega_m=1) is excluded at a confidence level of 2sigma and an open cosmology with low mass density (Omega_m = 0.3) and no dark energy contribution is excluded at a confidence level greater than 1 sigma. Inversely, by assuming prior knowledge about the cosmological model, the cosmology-evolution diagram can be used to gain useful insights about the redshift evolution of the structural parameters of baryonic discs hosted in dark matter halos of nearly equal masses.Comment: 14 pages and 11 figures. A&A in pres

Gaia data release 1: Principles of the photometric calibration of the G band

Context. Gaia is an ESA cornerstone mission launched on 19 December 2013 aiming to obtain the most complete and precise 3D map of our Galaxy by observing more than one billion sources. This paper is part of a series of documents explaining the data processing and its results for Gaia Data Release 1, focussing on the G band photometry. Aims. This paper describes the calibration model of the Gaia photometric passband for Gaia Data Release 1. Methods. The overall principle of splitting the process into internal and external calibrations is outlined. In the internal calibration, a self-consistent photometric system is generated. Then, the external calibration provides the link to the absolute photometric flux scales. Results. The Gaia photometric calibration pipeline explained here was applied to the first data release with good results. Details are given of the various calibration elements including the mathematical formulation of the models used and of the extraction and preparation of the required input parameters (e.g. colour terms). The external calibration in this first release provides the absolute zero point and photometric transformations from the Gaia G passband to other common photometric systems. Conclusions. This paper describes the photometric calibration implemented for the first Gaia data release and the instrumental effects taken into account. For this first release no aperture losses, radiation damage, and other second-order effects have not yet been implemented in the calibration.Comment: 15 pages, 16 figures, Gaia data release 1 documentation special volum