Hubble flow around Fornax cluster of galaxies
Abstract
Aims: This work aims to provide a new mass estimate for the Fornax cluster and the Fornax-Eridanus complex, avoiding methods like the virial or fits of the X-ray emission profile, which assume that the system is in equilibrium. This is probably not the case for Fornax, because it is still in process of formation.
Methods: Our mass estimate is based on determination of the zero-velocity surface, which, in the context of the spherical infall model, permits an evaluation of the total mass inside such a surface. The zero-velocity surface radius R0 was estimated either by a running median procedure or by fitting the data to the velocity field expected from the spherical model, including effects of the cosmological constant. The velocity field in a region within 20 Mpc of the Fornax center was mapped using a list of 109 galaxies whose distances have an average accuracy of 0.31 mag in their distance modulus.
Results: Our analysis indicates that the mass of the Fornax cluster itself is [0.40-3.32] × 1014 M⊙ inside a radius of [2.62-5.18] Mpc while the mass inside [3.88-5.60] Mpc, corresponding to the Fornax-Eridanus complex, is [1.30-3.93] × 1014 M⊙.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- August 2011
- DOI:
- 10.1051/0004-6361/201016004
- arXiv:
- arXiv:1106.1291
- Bibcode:
- 2011A&A...532A.104N
- Keywords:
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- galaxies: clusters: individual: Fornax;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Version 1. 13 pages, 10 figures, 5 tables. Accepted to Astronomy &