Ph. Marty

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Publications (2)0 Total impact

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    Article: The Diabolo photometer and the future of ground-based millimetric bolometer devices
    F. X. Desert, A. Benoit, Ph. Camus, M. Giard, E. Pointecouteau, N. Aghanim, J.-Ph. Bernard, N. Coron, J. -M. Lamarre, Ph. Marty, J. Delabrouille, V. Soglasnova
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    ABSTRACT: The millimetric atmospheric windows at 1 and 2 mm are interesting targets for cosmological studies. Two broad areas appear leading this field: 1) the search for high redshift star-forming galaxies and 2) the measurement of Sunyaev-Zel'dovich (SZ) effect in clusters of galaxies at all redshifts. The Diabolo photometer is a dual-channel photometer working at 1.2 and 2.1 mm and dedicated to high angular resolution measurements of the Sunyaev--Zel'dovich effect towards distant clusters. It uses 2 by 3 bolometers cooled down to 0.1 K with a compact open dilution cryostat. The high resolution is provided by the IRAM 30 m telescope. The result of several Winter campaigns are reported here, including the first millimetric map of the SZ effect that was obtained by Pointecouteau et al. (2001) on RXJ1347-1145, the non-detection of a millimetric counterpart to the radio decrement towards PC1643+4631 and 2 mm number count upper limits. We discuss limitations in ground-based single-dish millimetre observations, namely sky noise and the number of detectors. We advocate the use of fully sampled arrays of (100 to 1000) bolometers as a big step forward in the millimetre continuum science. Efforts in France are briefly mentionned. Comment: 7 pages, 6 figures, to appear in the Proceedings of the 2K1BC ``Experimental Astronomy at millimeter wavelengths'', Breuil-Cervinia (AO) Italy - July 9 - 13, 2001, Eds. M. De Petris et al
    12/2001;
  • Source
    Article: The XMM-Newton $\Omega$ Project
    J G Bartlett, N. Aghanim, M. Arnaud, J.-Ph. Bernard, A. Blanchard, M. Boer, D. J. Burke, C. A. Collins, M. Giard, D. H. Lumb, S. Majerowicz, Ph. Marty, D. Neumann, J. Nevalainen, R. C. Nichol, C. Pichon, A. K. Romer, R. Sadat, C. Adami
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    ABSTRACT: The abundance of high-redshift galaxy clusters depends sensitively on the matter density $\OmM$ and, to a lesser extent, on the cosmological constant $\Lambda$. Measurements of this abundance therefore constrain these fundamental cosmological parameters, and in a manner independent and complementary to other methods, such as observations of the cosmic microwave background and distance measurements. Cluster abundance is best measured by the X-ray temperature function, as opposed to luminosity, because temperature and mass are tightly correlated, as demonstrated by numerical simulations. Taking advantage of the sensitivity of XMM-Newton, our Guaranteed Time program aims at measuring the temperature of the highest redshift (z>0.4) SHARC clusters, with the ultimate goal of constraining both $\OmM$ and $\Lambda$.
    07/2001;
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