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

Author(s)
Juan Carlos Vega Beltran, Werner Zeilinger, P Amico, Mathias Schultheis, Enrico Maria Corsini, Jose Gabriel Funes, John E. Beckman, Francesco Bertola
Abstract

Rotation curves and velocity dispersion profiles are presented for both the stellar and gaseous components along five different position angles (PA = 5°, 50°, 95°, 125°, and 155°) 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] (? 6583.4 A°)/Ha 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 Ha regions along all the bar, the spiral-arm pattern. It is consistent with scenarios of bar-induced evolution from later to earlier-type galaxies.

Organisation(s)
Department of Astrophysics
External organisation(s)
Institute of Astrophysics of the Canary Islands, European Southern Observatory (Germany), University of Padova, Vatican Observatory
Journal
Astronomy & Astrophysics Supplement Series
Volume
131
Pages
105-114
No. of pages
10
ISSN
0365-0138
Publication date
1998
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy
Portal url
https://ucrisportal.univie.ac.at/en/publications/7cbcf520-c826-4f2e-b24a-333ee82a5950