Summary: L75
The Astrophysical Journal, 583:L75--L78, 2003 February 1
# 2003. The American Astronomical Society. All rights reserved. Printed in U.S.A.
NGC 4608 AND NGC 5701: BARRED GALAXIES WITHOUT DISKS?
D. A. Gadotti and R. E. de Souza
Departamento de Astronomia, Instituto de Astronomia, Geof��sica e Cie�ncias Atmosfe�ricas, Universidade de Sa�o Paulo, Rua do Mata�o, 1226 Cidade
Universitaria CEP, 05508�900 Sa�o Paulo SP, Brazil; dimitri@astro.iag.usp.br, ronaldo@astro.iag.usp.br
Received 2002 August 23; accepted 2002 December 23; published 2003 January 8
ABSTRACT
We have performed for the first time in the literature a two�dimensional structural analysis on the barred
lenticular and face�on galaxies NGC 4608 and NGC 5701. The results indicate that either these galaxies have
never had large disks or their disks were almost completely destroyed by their strong bars because of secular
evolution processes. We discuss these surprising conclusions, checking for signs of secular evolution, considering
bar�forming instabilities, and suggesting, based on N�body simulations, a new mechanism to form bars in spheroids,
which includes nonspherical halos. Quantitative predictions from our new mechanism are compared with those
from other recent models for bar formation and evolution.
Subject headings: galaxies: evolution --- galaxies: halos --- galaxies: individual (NGC 4608, NGC 5701) ---
galaxies: structure --- methods: n�body simulations
1. INTRODUCTION
The most widely accepted mechanism to produce bars in

Source: Alexei, Dimitri - European Southern Observatory

Collections: Physics