A&A 375, 338-343 (2001)

DOI: 10.1051/0004-6361:20010847

## The velocity field of collapsing spherical structures

##### Limitations of the spherical infall model in mass estimation

**N. Hiotelis**

Lyceum of Naxos, Chora of Naxos, Naxos 84300, Greece

(Received 15 January 2001 / Accepted 28 May 2001 )

** Abstract **

We assume that the amplitude of the caustics in
redshift space is a sum of two components: the first one can be
predicted by the spherical infall model with no random motion, and
the second is due to the random motion distribution. Smooth model
curves are used to estimate the maximum values of the first
component for the Coma cluster. Then, an approximation of the
radial component of the infall velocity -based on the above
curves -is derived and a mass profile of the cluster is
calculated. This mass profile, that is an upper limit for the
spherical infall model, combined with estimations given by other
authors provides an approximation of a lower limit for the mass of
the system.

**Key words:**galaxies: clusters: general

**--**galaxies: clusters: individual: coma cluster

**--**cosmology: large-scale structure of Universe

SIMBAD Objects

**©**

*ESO 2001*