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Astron. Astrophys. 353, 427-434 (2000)

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Density profiles of dark matter halos in an improved secondary infall model

A. Del Popolo 1,2, M. Gambera 1,3, E. Recami 4,5,6 and E. Spedicato 2

1 Istituto di Astronomia dell'Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy
2 Dipartimento di Matematica, Università Statale di Bergamo, Piazza Rosate 2, I-24129 Bergamo, Italy
3 Osservatorio Astrofisico di Catania and CNR-GNA, Viale A. Doria 6, I-95125 Catania, Italy
4 Facoltá di Ingegneria, Università Statale di Bergamo, Viale G. Marconi 5, I-24044 Dalmine, Bergamo, Italy
5 I.N.F.N., Sezione di Milano, Milano, Italy
6 C.C.S. and D.M.O./FEEC, State University at Campinas, S. P., Brazil

Received 1 December 1998 / Accepted 11 May 1999


In this paper we calculate the density profiles of virialized halos both in the case of structure evolving hierarchically from a scale-free Gaussian [FORMULA]field having a power spectrum [FORMULA] in a [FORMULA] Universe and in the case of the CDM model, by using a modified version of Hoffman & Shaham's (1985) (hereafter HS) and Hoffman's (1988) model. We suppose that the initial density contrast profile around local maxima is given by the mean peak profile introduced by Bardeen et al. (1986) (hereafter BBKS), and is not just proportional to the two-point correlation function, as assumed by HS. We show that the density profiles, both for scale-free Universes and the CDM model, are not power-laws but have a logarithmic slope that increases from the inner halo to its outer parts. Both scale-free, for [FORMULA], and CDM density profiles are well approximated by Navarro et al. (1995, 1996, 1997) profile. The radius a, at which the slope [FORMULA], is a function of the mass of the halo and in the scale-free models also of the spectral index n.

Key words: cosmology: theory – cosmology: large-scale structure of Universe – galaxies: formation

Send offprint requests to: A. Del Popolo (adelpopolo@alpha4.ct.astro.it)

© European Southern Observatory (ESO) 2000

Online publication: December 17, 1999