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Le gaz moleculaire dans les galaxies abritant un courant de refroidissement

Abstract : Theoretical predictions of radiative cooling of the intra-cluster medium (ICM ) from 10^7 K to a very cold phase has never been prooved directly. The new generation of X-ray satellites Chandra and XMM-Newton has permitted to explore the central part of some of theselarge structures, where a cooling flow is active. The main question concerning the cooling flows is about the fate of the cooling gas. The work presented here is the detection of cold molecular gas in the central region of several clusters of galaxies with cooling flow, obtained with the IRAM 30m telescope. Those detections can be interpreted as the signature of the cold component deposited along the flow. But molecular gas masses derived are still lower than what is predicted by X-ray data analyses. To try to constrain the origin of the cold gas detected, we studied one peculiar object: Abell 1795. A spectral analysis of Chandra X-ray data has been performed to give an estimation of important parameters describing the intra-cluster gas (temperature, abundance, column density, mass deposition rates). To understand the link between the cold gas detected in Abell 1795 and the cooling flow, interferometric observations with the IRAM Plateau de Bure instrument have been performed. The morphology and the dynamics of the molecular gas, emitting in CO lines, is presented and discussed. The cold gas is associated with hotter components already pointed out in the cluster core. These observations are consistent with a radiative cooling to very low temperatures. The cold gas is then a reservoir available to fuel the star formation, existing in the same region. The interaction of the central radio-source with the ICM is underlined and may play an important role in the cooling flow scenario (AGN-feedback) . New observations (Plateau de Bure, VLT) are in progress now to increase the number of sources observed and better understand the place of the cold gas detected in cooling flow clusters of galaxies.
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https://tel.archives-ouvertes.fr/tel-00338287
Contributor : Philippe Salome <>
Submitted on : Wednesday, November 12, 2008 - 3:19:43 PM
Last modification on : Monday, December 14, 2020 - 9:49:05 AM
Long-term archiving on: : Monday, June 7, 2010 - 7:48:16 PM

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  • HAL Id : tel-00338287, version 1

Citation

Philippe Salome. Le gaz moleculaire dans les galaxies abritant un courant de refroidissement. Astrophysique [astro-ph]. Université Paris Sud - Paris XI, 2004. Français. ⟨tel-00338287⟩

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