... Groups

Based on observations collected at the European Southern Observatory, La Silla, Chile and at the Canada-France-Hawaii Observatory, Hawaii, USA.

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...

Tables 1 and 2, Figs. 1, 3, 5, 7, 9, 11, 13, 15, 23 are only available in electronic form at http://www.edpsciences.org

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... GHASP

http://www.oamp.fr/interferometrie/ghasp/ghasp.html

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... (NED

NASA/IPAC Extragalactic Database.

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...${\rm Log}~L_{\rm X}~<~42.36~\rm erg~s^{-1}$)

Ponman et al. (1996) have used H₀=50 km s^-1 Mpc^-1; in the present paper we use H₀=75 km s^-1 Mpc^-1.

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