The Energetics of Flat and Rotating Early-Type Galaxies and Their X-Ray Luminosity

  • S. Pellegrini
  • L. Ciotti
Conference paper
Part of the International Astronomical Union / Union Astronomique Internationale book series (IAUS, volume 171)


A multivariate statistical analysis of data measuring the optical and X-ray properties of the Einstein sample of early-type galaxies (Eskridge et al. 1995) showed that: 1) on average S0s have lower X-ray luminosity L X at fixed optical luminosity L B than do Es; 2) at fixed L B the X-ray brightest galaxies are also the roundest; this correlation holds for both morphological subsets of Es and S0s. We investigate whether a flat and partially rotationally supported galaxy is expected to host a different gas flow phase (and so a largely different amount of hot gas) with respect to a spherical pressure supported galaxy of the same L B. This is accomplished using the global energetic balance of the hot gas flows, and axisymmetric two-component galaxy models (Ciotti and Pellegrini 1995).


  1. Eskridge, P., Fabbiano, G., and Kim, D.W., (1995), Ap. J. Suppl. Ser., 442, 523ADSGoogle Scholar
  2. Ciotti, L., and Pellegrini, S., 1995, submitted to M.N.R.A.S.Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1996

Authors and Affiliations

  • S. Pellegrini
    • 1
  • L. Ciotti
    • 2
  1. 1.Dipartimento di AstronomiaBolognaItaly
  2. 2.Osservatorio Astronomico di BolognaBolognaItaly

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