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Date and Time of the Query: 2019-07-18 T02:21:22 PDT
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Notes for object ARP 321 NED01

3 note(s) found in NED.


1. 1964RC1...C...0000d
Re:[RC1] A0937A
Part of VV 116.

2. 1963MCG3..C...0000V
Re:MCG -01-25-008
In a remarkable nest -- dense group of five galaxies. Photo:
VV Atlas No. 116 and Ap J 134, 248, where the Burbidges give redshifts:
MCG -01-25-009 = a = A: E +6356
MCG -01-25-010 = e = B: E +6576
(MCG -01-25-008 = c)? = C: S +6631 H{alpha} and {lambda} 6583 and 6548 [N II].
(MCG -01-25-012 = d)? = D: S +6630 H{alpha}, defined rotation and mass.
In the tables: our notation in the photo and VV Atlas is given with
lower-case letters, and the upper-case letters is the Burbidges' notation.

3. 1961AJ.....66..541B
Re:[RC2] A0936-04A
3. VV 116 Group
This quintet was discovered by Vorontsov-Velyaminov (1960) and it has been
investigated by us (Burbidge and Burbidge 1959b, 1961b; photographs are
published in both references). It is a compact group of two ellipticals and
three spirals, and a narrow fairly bright filament that runs between the fainter
of the two of the spirals. This filament might alternatively be a faint sixth
member of the group. Magnitudes are not available for these galaxies, but we
have named them A-E in order of decreasing apparent brightness on our plates.
Velocities for four of the five members have been obtained, and they are: A
(elliptical), +6356+/-40 km/sec; B (elliptical), +6576+/-40 km/sec; C (spiral),
+6631+/-30 km/sec; D (spiral), +6230+/-30 km/sec. Spiral C has very strong
emission lines; spiral D has less strong emission. For D it was possible to
obtain an estimate of the rotation from the tilted H{alpha} emission line.
By assuming that the masses of the ellipticals were 10X those of the spirals,
and by allowing for the unmeasured galaxy E by multiplying the kinetic energy by
5/4, we found that the virial theorem could be satisfied by masses of 5.5X
10^11^ M_sun_ for the ellipticals and 5.5X 10^10^ M_sun_ for the spirals, i.e.,
a total mass of 1.3 X 10^12^ M_sun_. Here we can make a direct comparison with
the mass of D independently estimated from its rotation; the value thus obtained
is 3.3X 10^10^ M_sun_. This value is in sufficiently good agreement with the
average value of 5.5 X 10^10^ M_sun_ obtained from the virial theorem for us to
conclude that the system is stable, although ultimately, of course, it will
suffer the rearrangement of kinetic energy that occurs in trapezium-like systems
resulting in disruption of the compact configuration.
Two final comments must be made: (i) if galaxy E is found to have a high
relative velocity, then the group may still prove to be unstable. (ii) The
reason why it appears to be stable on the evidence of the velocities. given
above is that the galaxies are very close together - their average
three-dimensional separation is only about 37 kpc. The outer regions of at least
four of them appear to be interconnected.


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