Mixed early and late-type properties in the bar of NGC 6221: Evidence for evolution along the Hubble sequence?

Vega Beltran, J. C.; Zeilinger, W. W.; Amico, P.; Schultheis, M.; Corsini, E. M.; Funes, J. G.; Beckman, J. E.; Bertola, F.
Referencia bibliográfica

Astronomy and Astrophysics Supplement, v.131, p.105-114

Fecha de publicación:
7
1998
Número de autores
8
Número de autores del IAC
3
Número de citas
15
Número de citas referidas
12
Descripción
Rotation curves and velocity dispersion profiles are presented for both the stellar and gaseous components along five different position angles (PA =5(deg) , 50(deg) , 95(deg) , 125(deg) , and 155(deg) ) of the nearby barred spiral NGC 6221. The observed kinematics extends out to about 80'' from the nucleus. Narrow and broad-band imaging is also presented. The radial profiles of the fluxes ratio [N II] (lambda 6583.4 Angstroms )/Hα reveal the presence of a ring-like structure of ionized gas, with a radius of about 9'' and a deprojected circular velocity of about 280 km;s(-1) . The analysis of the dynamics of the bar indicates this ring is related to the presence of an inner Lindblad resonance (ILR) at 1.3 kpc. NGC 6221 is found to exhibit intermediate properties between those of the early-type barred galaxies: the presence of a gaseous ring at an ILR, the bar edge located between the ILR's and the corotation radius beyond the steep rising portion of the rotation curve, the dust-lane pattern, and those of the late-type galaxies: an almost exponential surface brightness profile, the presence of Hα regions along all the bar, the spiral-arm pattern. It is consistent with scenarios of bar-induced evolution from later to earlier-type galaxies. Tables 3, 4, 5, 6, 7 and 8 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html Based on observations collected at the European Southern Observatory, La Silla (Chile).