UGC 07668a also contributes to F12291+0412.
SN 1988M, discovered by Filippenko, Shields, & Sargent (1988),
occurred in NGC 4496B (cz = 4510 km s^-1^), an optical double to
NGC 4496A (cz = 1730 km s^-1^), the host galaxy of SN Ia 1960F (see
section 3.3.7). NGC 4496A,B were imaged as part of a project to measure
a Cepheid-based distance to SN 1960F (Saha et al. 1996a), so a large
number of F555W and F814W images are available. These were combined to
provide very deep images in both bands. We show the SN environment in
the F555W image in Figure 6. The position is based on a nuclear offset
(12.5" south), measured accurately from a two-dimensional spectrum
including the SN by Filippenko et al. (1988); the uncertainty in the
measurement is likely +/-3". However, comparing to ground-based images
of these galaxies, the SN environment is very near the edge of the WFPC2
chip, so we conservatively assign an uncertainty of 5" to the SN
position in the HST image. The SN appears to have occurred along a
faint extension of a spiral arm in NGC 4496B. Several very faint stars
can be barely resolved by DAOPHOT in the environment, and they appear to
be quite red; however, the extinction is unknown. SN 1988M may have
occurred among these red stars, either supergiants or reddened OB stars,
with ages possibly as young as about 20 Myr.
As discussed extensively in Filippenko et al. (1988), NGC 4496A,B (VV 76)
form an optical, rather than a physical, binary system, with systemic
velocities of cz = 1700 km s^-1^ and 4510 km s^-1^, respectively. The
spectrum of NGC 4496A shown in Figure 67 is not of its nucleus (which was
not observed); it was extracted from an emission-line knot located ~ 19"
south of the nucleus of NGC 4496B (PA = 180 ^deg^; see Filippenko et al.
1988 for details).
Karachentsev 343 [with NGC 4496A]
March 31/April 1, 1982
The image of NGC 4496A overlaps that of
NGC 4496B; the centers have an angular
separation of 0.9'. The redshifts listed by
Karachentsev, v_o(4496 A) = 1831 km/s and
v_o(4496B) = 4509 km/s, would put the
companion far in the background. This is curious
because the brightnesses of the numerous
HII-region candidates in both galaxies seem closely
the same, suggesting that the two galaxies are at
nearly the same distance. Additional data are
needed, but an apparent confirmation of the
large redshift of NGC 4496B is given by the
21-cm redshift listed in the VCC of
v_sun_ = 4548 km/s (or v_o = 4391 km/s) attributed
to unpublished observations by Hoffman, Helou,
and Salpeter (1984, private communication).
This may be the same measurement published by
Hoffman et al. (1989), where v_sun_ = 4546 km/s
is listed for NGC 4496B.
Both NGC 4496A and 4496B are listed in
the VCC as non-members of the Virgo Cluster.
PGC 041473 = NGC 4496B = UGC 7668b. Note improved position in Table 5 of
Two galaxies (with VCC 1375) superposed on each other.
Not recognized by CGCG. DVP did separate the two but give incorrect data.
New estimated magnitudes and diameters.
= NGC 4505B
= Holm 415b
in VV 076
in Kara 343
Colliding (?) pair with NGC 4496A at 0.9 arcmin
= Holm 415b
Fainter of two overlapping systems. Colliding or strongly iteracting pair
with NGC 4496A 0.9 arcmin.
Magnitude and colors are for the two components together.
I.A.U. Circ. 1721.
I.A.U. Circ. 1723.
I.A.U. Circ. 1725.
I.A.U. Circ. 1734.
I.A.U. Circ. 1736.
C.R. Acad. Sc., Paris, 250, 3952, 1960.
P.A.S.P., 73, 175, 1961.