The XMM-LSS survey: The XMDS/VVDS 4 sigma catalogue

We present a first catalogue of X-ray sources resulting from the central area of the XMM-LSS (Large Scale Structure survey). We describe the reduction procedures and the database tools we developed and used to derive a well defined catalogue of X-ray sources. The present catalogue is limited to a sub-sample of 286 sources detected at 4 sigma in the 1 deg^2 area covered by the photometric VVDS (VIRMOS VLT Deep Survey), which allows us to provide optical and radio identifications. We also discuss the X-ray properties of a larger X-ray sample of 536 sources detected at > 4 sigma in the full 3 deg^2 area of the XMM Medium Deep Survey (XMDS) independently of the optical identification. We also derive the logN-logS relationship for a sample of more than one thousand sources that we discuss in the context of other surveys at similar fluxes.Comment: 15+6 pages, 12 figures, accepted for publication in Astronomy & Astrophysics The online catalogue announced in the paper will be accessible in about 2 weeks due to technical reasons Fig. 2 replaced with a low resolution on

The VIRMOS deep imaging survey: I. overview and survey strategy

This paper presents the CFH12K-VIRMOS survey: a deep B, V, R and I imaging survey in four fields totalling more than 17 deg^2, conducted with the 30x40 arcmin^2 field CFH-12K camera. The survey is intended to be a multi-purpose survey used for a variety of science goals, including surveys of very high redshift galaxies and weak lensing studies. Four high galactic latitude fields, each 2x2 deg^2, have been selected along the celestial equator: 0226-04, 1003+01, 1400+05, and 2217+00. The 16 deg^2 of the "wide" survey are covered with exposure times of 2h, 1.5h, 1h, 1h, while the 1.3x1 deg^2 area of the "deep" survey at the center of the 0226-04 field is covered with exposure times of 7h, 4.5h, 3h, 3h, in B,V,R and I respectively. The data is pipeline processed at the Terapix facility at the Institut d'Astrophysique de Paris to produce large mosaic images. The catalogs produced contain the positions, shape, total and aperture magnitudes for the 2.175 million objects. The depth measured (3sigma in a 3 arc-second aperture) is I_{AB}=24.8 in the ``Wide'' areas, and I_{AB}=25.3 in the deep area. Careful quality control has been applied on the data as described in joint papers. These catalogs are used to select targets for the VIRMOS-VLT Deep Survey, a large spectroscopic survey of the distant universe (Le F\`evre et al., 2003). First results from the CFH12K-VIRMOS survey have been published on weak lensing (e.g. van Waerbeke & Mellier 2003). Catalogs and images are available through the VIRMOS database environment under Oracle ({\tt http://www.oamp.fr/virmos}). They will be open for general use on July 1st, 2003.Comment: 17 pages including 9 figures, submitted to A&

The VIMOS VLT Deep Survey: the faint type-1 AGN sample

We present the type-1 active galactic nuclei (AGN) sample extracted from the VIMOS VLT Deep Survey first observations of 21000 spectra in 1.75 square degree. This sample, which is purely magnitude limited, free of morphological or color selection biases, contains 130 broad line AGN (BLAGN) spectra with redshift up to 5. Our data are divided into a wide (Iab < 22.5) and a deep (Iab < 24) subsample containing 56 and 74 objects respectively. Because of its depth and selection criteria, this sample is uniquely suited to study the population of faint type-1 AGN. Our measured surface density (~ 472 +- 48 BLAGN per square degree with Iab < 24) is significantly higher than that of any other optically selected sample of BLAGN with spectroscopic confirmation. By applying a morphological and color analysis to our AGN sample we find that: (1)~23% of the AGN brighter than Iab=22.5 are classified as extended; this percentage increases to ~42% for those with z < 1.6; (2) a non-negligible fraction of our BLAGN are lying close to the color space area occupied by stars in u*-g' versus g'-r' color-color diagram. This leads us to the conclusion that classical optical ultraviolet preselection technique, if employed at such deep magnitudes (Iab=22.5) in conjuction with a preselection of point-like sources, can miss miss up to ~35% of the AGN population. Finally, we present a composite spectrum of our sample of objects. While the continuum shape is very similar to that of the SDSS composite at short wavelengths, it is much redder than it at lambda > 3000 A. We interpret this as due to significant contamination from emission of the host galaxies, as expected from the faint absolute magnitudes sampled by our survey.Comment: Accepted to A&A, 18 pages, 14 figure

The Vimos VLT Deep Survey: Global properties of 20000 galaxies in the I_AB<=22.5 WIDE survey

The VVDS-Wide survey has been designed with the general aim of tracing the large-scale distribution of galaxies at z~1 on comoving scales reaching ~100Mpc/h, while providing a good control of cosmic variance over areas as large as a few square degrees. This is achieved by measuring redshifts with VIMOS at the ESO VLT to a limiting magnitude I_AB=22.5, targeting four independent fields with size up to 4 sq.deg. each. The whole survey covers 8.6 sq.deg., here we present the general properties of the current redshift sample. This includes 32734 spectra in the four regions (19977 galaxies, 304 type I AGNs, and 9913 stars), covering a total area of 6.1 sq.deg, with a sampling rate of 22 to 24%. The redshift success rate is above 90% independently of magnitude. It is the currently largest area coverage among redshift surveys reaching z~1. We give the mean N(z) distribution averaged over 6.1 sq.deg. Comparing galaxy densities from the four fields shows that in a redshift bin Deltaz=0.1 at z~1 one still has factor-of-two variations over areas as large as ~0.25 sq.deg. This level of cosmic variance agrees with that obtained by integrating the galaxy two-point correlation function estimated from the F22 field alone, and is also in fairly good statistical agreement with that predicted by the Millennium mocks. The variance estimated over the survey fields shows explicitly how clustering results from deep surveys of even ~1 sq.deg. size should be interpreted with caution. This paper accompanies the public release of the first 18143 redshifts of the VVDS-Wide survey from the 4 sq.deg. contiguous area of the F22 field at RA=22h, publicly available at http://cencosw.oamp.frComment: Accepted for publication on Astronomy & Astrophysic

The VIMOS VLT Deep Survey: the group catalogue

[Abridged] We present a homogeneous and complete catalogue of optical groups identified in the purely flux limited (17.5<=I<=24.0) VIMOS-VLT Deep Survey (VVDS). We use mock catalogues extracted from the MILLENNIUM simulation, to correct for potential systematics that might affect the overall distribution as well as the individual properties of the identified systems. Simulated samples allow us to forecast the number and properties of groups that can be potentially found in a survey with VVDS-like selection functions. We use them to correct for the expected incompleteness and also to asses how well galaxy redshifts trace the line-of-sight velocity dispersion of the underlying mass overdensity. In particular, we train on these mock catalogues the adopted group-finding technique (the Voronoi-Delaunay Method, VDM). The goal is to fine-tune its free parameters, recover in a robust and unbiased way the redshift and velocity dispersion distributions of groups and maximize the level of completeness (C) and purity (P) of the group catalogue. We identify 318 VVDS groups with at least 2 members within 0.2<=z<=1.0, among which 144 (/30) with at least 3 (/5) members. The sample has globally C=60% and P=50%. Nearly 45% of the groups with at least 3 members are still recovered if we run the algorithm with a parameter set which maximizes P (75%). We exploit the group sample to study the redshift evolution of the fraction f_b of blue galaxies (U-B<=1) within 0.2<=z<=1. We find that f_b is significantly lower in groups than in the whole ensemble of galaxies irrespectively of their environment. These quantities increase with redshift, with f_b in groups showing a marginally significant steeper increase. We also confirm that, at any explored redshift, f_b decreases for increasing group richness, and we extend towards fainter luminosities the magnitude range over which this result holds.Comment: Submitted to A&A, revised version after referee comments, Table 5 adde

The VVDS-VLA Deep Field II. Optical and near infrared identifications of VLA S(1.4GHz)>80 microJy sources in the VIMOS VLT Deep Survey VVDS-02h field

In this paper we present the optical and near-infrared identifications of the 1054 radio sources detected in the 20cm deep radio survey down to a 5sigma flux limit of about 80 microJy obtained with the VLA in the VIMOS VLT Deep Survey VVDS-02h deep field. Using U,B,V,R,I and K data, we identified 718 radio sources (~74% of the whole sample). The photometric redshift analysis shows that, in each magnitude bin, the radio sample has a higher median photometric redshift than the whole optical sample, while the median (V-I) color of the radio sources is redder than the median color of the whole optical sample. These results suggest that radio detection is preferentially selecting galaxies with higher intrinsic optical luminosity. From the analysis of the optical properties of the radio sources as function of the radio flux, we found that while about 35% of the radio sources are optically unidentified in the higher radio flux bin (S> 1.0 mJy), the percentage of unidentified sources decreases to about 25% in the faintest bins (S< 0.5 mJy). The median I magnitude for the total sample of radio sources,i.e. including also the unidentified ones, is brighter in the faintest radio bins than in the bin with higher radio flux. This suggests that most of the faintest radio sources are likely to be associated to relatively lower radio luminosity objects at relatively modest redshift, rather than radio-powerful, AGN type objects at high redshift.Comment: 15 pages, 11 figs. A&A in pres

PpiA, a Surface PPIase of the Cyclophilin Family in Lactococcus lactis

Background: Protein folding in the envelope is a crucial limiting step of protein export and secretion. In order to better understand this process in Lactococcus lactis, a lactic acid bacterium, genes encoding putative exported folding factors like Peptidyl Prolyl Isomerases (PPIases) were searched for in lactococcal genomes. Results: In L. lactis, a new putative membrane PPIase of the cyclophilin subfamily, PpiA, was identified and characterized. ppiA gene was found to be constitutively expressed under normal and stress (heat shock, H2O2) conditions. Under normal conditions, PpiA protein was synthesized and released from intact cells by an exogenously added protease, showing that it was exposed at the cell surface. No obvious phenotype could be associated to a ppiA mutant strain under several laboratory conditions including stress conditions, except a very low sensitivity to H2O2. Induction of a ppiA copy provided in trans had no effect i) on the thermosensitivity of an mutant strain deficient for the lactococcal surface protease HtrA and ii) on the secretion and stability on four exported proteins (a highly degraded hybrid protein and three heterologous secreted proteins) in an otherwise wild-type strain background. However, a recombinant soluble form of PpiA that had been produced and secreted in L. lactis and purified from a culture supernatant displayed both PPIase and chaperone activities. Conclusions: Although L. lactis PpiA, a protein produced and exposed at the cell surface under normal conditions, displaye

Concepts de logistique appliqués à l'industrie pharmaceutique

CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

LA SCARLATINE STAPHYLOCOCCIQUE DE L'ENFANT PAR PRODUCTION D'ENTEROTOXINE B (A PROPOS DE DEUX OBSERVATIONS)

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

LES FAUX-POSITIFS DU TEST DE LA SUEUR, A PROPOS DE QUATRE OBSERVATIONS

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF