Bibcode
DOI
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
Journal
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.