NGC 4178.---SBc?: System nearly edge-on. No nucleus or bulge, but a
long, high-contrast bar. Two broad, low contrast spiral arms emerge
from the ends of the bar. These fade into the ambient disk after
~120deg. There are three very bright star-forming knots on the SW side
of the galaxy, with many fainter ones throughout the disk.
Large irregular galaxy. F12102+1108 is the correct identification
despite the large optical/FSC offset.
March 18/19, 1982
103aO + GG385
NGC 4178 is listed as a cluster member in
the Virgo Cluster Catalog (Binggeli, Sandage, and
Tammann 1985). It is illustrated on a common
scale with other cluster members in the Atlas of
Virgo Cluster Spirals (Sandage, Binggeli, and
Tammann 1985a, panel 6). The angular
diameter is large at D_25_ = 5.0'. The redshift of
NGC 4178 is v_o = 224 km/s, illustrating the
large virial velocity variation among the Virgo
Cluster members. From the characteristics of the
HII regions and the lack of individual resolved
stars brighter than B = 23, there is no question
that the galaxy is much more distant than its
small redshift would indicate.
The bar consists of HII regions in a thin
straight pattern. Two large HII-region complexes
exist in one of the arms. Halo diameters of these
compound associations are about 5".
= IC 3042
Photometry and Isodensitometry:
Ap. J. Suppl., 26, No. 230, 1973.
Rotation Curve and Systemic Velocity:
Astr. Ap., 8, 364, 1970.
P.A.S.P., 76, 220, 1964.
Var. Star Bull.(USSR), 15, 107, 1964.
Mem. S.A. Ital., 36, 299, 1965 = Cont. Asiago, No. 182.
SB(rs)dm (de Vaucouleurs), Sc+ (Holmberg)
Companion 4.4, 112, 0.5 x 0.4, late spiral
= IC 3042
Small, bright narrow bar: 0.7 arcmin x 0.1 arcmin. Several faint, partially
resolved, branching arms.
I.A.U. Symp., No. 5, 1958 = Lick Contr. II, No. 81, 1958.
I.A.U. Circ., 1830, 31, 1963.
I.A.U. Circ., 1830, 32, 1963.
HMS Note No. 127
Bright central bar.
Redshift from absorption-line spectrum.
HMS Note No. 128
Emission patch approximately 100 arcsec [south-west] of center of bar.
Difference in velocity between bar and patch is so small that its
interpretation as rotational motion is uncertain.