The kinematics and morphology of NGC 520

Standord, S. A.; Balcells, M.
Bibliographical reference

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 355, May 20, 1990, p. 59-69.

Advertised on:
5
1990
Number of authors
2
IAC number of authors
0
Citations
43
Refereed citations
40
Description
New long-slit optical spectroscopy and optical and NIR images of NGC 520 are presented. Velocity-dispersion and radial-velocity profiles are obtained from the spectra with the Fourier quotient and cross-correlation techniques. At the NW optical emission peak, a sharp rise in the velocity dispersions implies a concentration of mass. The NW optical peak is also apparent as a peak in the K-band image, whose NIR colors are consistent with the presence of a typical bulge steller population. These data suggest that the NW peak may be the bulge of one of two galaxies in the system. A larger bulge is clearly evident in the K-band image in the middle of an optical dust lane. The optical colors and H-alpha emission imply that both bulges and the disk of the NW galaxy have experienced recent star formation. The radial-velocity profile in the central 10 arcsec at the larger bulge is consistent with a counterrotating core, in agreement with the CO radial-velocity profile (Sanders et al., 1988). This core could be explained as an accreted gas-rich irregular galaxy which is forming a counterrotating stellar disk.