EDP Sciences
Free access
Volume 404, Number 3, June IV 2003
Page(s) 819 - 830
Section Galactic structure and dynamics
DOI http://dx.doi.org/10.1051/0004-6361:20030488

A&A 404, 819-830 (2003)
DOI: 10.1051/0004-6361:20030488

Projection effects on the FP thickness

A Monte-Carlo exploration
B. Lanzoni1 and L. Ciotti2, 3, 4

1  INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
2  Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy
3  Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
4  Princeton University Observatory, Peyton Hall, Princeton, NJ 08544-1001, USA

(Accepted 4 November 2002 / Accepted 21 March 2003)

We study the contribution of projection effects to the intrinsic thickness of the Fundamental Plane (FP) of elliptical galaxies. The Monte-Carlo mapping technique between model properties and observed quantities, introduced by Bertin et al. (2002), is extended to oblate, two-integrals galaxy models, with non-homologous density profiles, adjustable flattening, variable amount of ordered rotational support, and for which all the relevant projected dynamical quantities can be expressed in fully analytical way. In agreement with previous works, it is found that projection effects move models not exactly parallel to the edge-on FP, by an amount that can be as large as the observed FP thickness. The statistical contribution of projection effects to the FP thickness is however marginal, and the estimated physical FP rms thickness is $\simeq$ 90% of the observed one (when corrected for measurement errors).

Key words: galaxies: elliptical and lenticular, cD -- galaxies: fundamental parameters -- galaxies: kinematics and dynamics -- galaxies: photometry

Offprint request: B. Lanzoni, lanzoni@bo.astro.it

© ESO 2003