10 research outputs found

    AGAPE: a microlensing search in the direction of M31

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    A status report of the microlensing search by the pixel method in the direction of M31, on the 2 meter telescope at Pic du Midi is given. Pixels are stable to a level better than 0.5%. Pixel variations as small as 0.02 magnitude can clearly be detected

    The VIMOS VLT Deep Survey - First epoch VVDS-Deep survey: 11564 spectra with 17.5<=IAB<=24, and the redshift distribution over 0< z <=5

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    This paper presents the ``First Epoch'' sample from the VIMOS VLT Deep Survey (VVDS). The VVDS goals, observations, data reduction with VIPGI, and redshift measurement with KBRED are discussed. Data have been obtained with the VIsible Multi Object Spectrograph (VIMOS) on the ESO-VLT UT3, allowing to observe ~600 slits simultaneously at R~230. A total of 11564 objects have been observed in the VVDS-02h and VVDS-CDFS Deep fields over a total area of 0.61deg^2, selected solely on the basis of apparent magnitude 17.5 <=I_{AB} <=24. The VVDS covers the redshift range 0 < z <= 5. It is successfully going through the ``redshift desert'' 1.5<z<2.2, while the range 2.2<z<2.7 remains of difficult access because of the VVDS wavelength coverage.A total of 9677 galaxies have a redshift measurement, 836 are stars, 90 are AGNs, and a redshift could not be measured for 961 objects. There are 1065 galaxies with a measured redshift z>1.4. The survey reaches a redshift measurement completeness of 78% overall (93% including less reliable objects), with a spatial sampling of the population of galaxies of 25% and ~30% in the VVDS-02h and VVDS-CDFS. The redshift accuracy measured from repeated observations with VIMOS and comparison to other surveys is ~276km/s. From this sample we present for the first time the redshift distribution of a magnitude limited spectroscopic sample down to IAB=24. The redshift distribution has a median of z=0.62, z=0.65, z=0.70, and z=0.76, for magnitude limited samples with IAB<=22.5, 23, 23.5, and 24. A high redshift tail above redshift 2 and up to redshift 5 becomes readily apparent for IAB>23.5, probing the bright star forming population of galaxies. This sample provides an unprecedented dataset to study galaxy evolution over 90% of the life of the universeComment: 30 pages, accepted 22-Feb-05 in A&

    The Vimos VLT Deep Survey: Compact structures in the CDFS

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    We have used the Vimos VLT Deep Survey in combination with other spectroscopic, photometric and X-ray surveys from literature to detect several galaxy structures in the Chandra Deep Field South (CDFS). Both a friend-of-friend based algorithm applied to the spectroscopic redshift catalog and an adaptative kernel galaxy density and colour maps correlated with photometric redshift estimates have been used. We mainly detect a chain-like structure at z=0.66 and two massive groups at z=0.735 and 1.098 showing signs of ongoing collapse. We also detect two galaxy walls at z=0.66 and at z=0.735 (extremely compact in redshift space). The first one contains the chain-like structure and the last one contains in its center one of the two massive groups. Finally, other galaxy structures that are probably loose low mass groups are detected. We compare the group galaxy population with simulations in order to assess the richness of these structures and we study their galaxy morphological contents. The higher redshift structures appear to probably have lower velocity dispersion than the nearby ones. The number of moderatly massive structures we detect is consistent with what is expected for an LCDM model, but a larger sample is required to put significant cosmological constraints.Comment: 15 pages, 17 figures, accepted in A&

    AGAPE, an experiment to detect MACHO's in the direction of the Andromeda galaxy

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    The status of the Agape experiment to detect Machos in the direction of the andromeda galaxy is presented
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