ASTRO: Arp 80 and friends in faint IFN

Arp 80/NGC 2633 is located in northern Camelopardalis with a red shift
distance of about 100 million light-years. Other distance estimates
range from 89 million light-years to 108 million light-years with a mean
value of 96 million light-years. The latter is in surprisingly good
agreement with the redshift value. Arp put it in his category for
spiral galaxies with large high surface brightness companions. His
comment reads: "End of one arm heavy; absorption break in same arm near
nucleus." Note it doesn't mention the "high surface brightness
companion." Could that be because it doesn't exist? This has to be one
of the most puzzling entries in his atlas. I'd think a high surface
brightness companion would be easy to spot but where the blankety-blank
is it? The VV catalog seems to add my confusion when it reads: "3 or
more galaxies with one or two "bridges" (at the left). All nearly in
contact. Bordered by an arc above and below and still further above by a
wide spiral arm. ... The upper arc is terminated by zigzags, or by a
chance projection of a remote nest." Until that last sentence I thought
I might have the wrong galaxy but it does show a nice squiggle at the
end of the upper arm. That arm is quite a bit brighter than the other
arm. The UGC makes the most sense when it says of Arp 80: "Arp's class
'galaxies with one heavy arm' appears more appropriate." Amen to that!
I believe the absorption break Arp speaks of is at the other end from
the squiggle right where it meets the core region. At least I see a
strong dust band cutting straight across the arm there which is a very
unusual feature. But I can't fathom the companion or companions Arp and
the VV catalog mentions. Best I can do is the "zigzag" or "nest" at the
end of the arm that the VV catalog mentions. Both the NGC Project and
NED class it as SBb.

It does, however, have a companion. It is LEDA 213530 about 3 minutes
to the south and a bit east. Far from being on an arm it is apparently
a true companion having exactly the same redshift, 2160 km/s. NED
classes it as Im. It is quite blue as are a surprising number of the
galaxies in this image.

Below it is yet another companion NGC 2634. It is classed by NED as E1:
and simply as E by the NGC Project. Usually elliptical galaxies are
composed of old red stars but this one has outer shells of blue. The
POSS plates also show it brighter in blue than red light. Continuing
south yet we find yet another group member, NGC 2634A. NED classes it
as SB(s)bc? sp. The sp means it has spectral lines. It is apparently
an edge on barred spiral. It certainly has some bright knots of
activity in it. The shells of NGC 2634 are usually an indication it is
digesting a rather large meal after cannibalizing another galaxy well
into the past. I find its shells more interesting than Arp 80. Arp has
a class for such shell galaxies but didn't include this one though to me
its shells structure is better defined than some he did include. All
notes at NED agree it is not interacting with NGC 2634A.

Those 4 are the only ones with any redshift data but there are other
interesting galaxies in the image that I marked in the annotated image.
MAILYAN 035 is a very low surface brightness, and very fuzzy spiral
galaxy that is also very blue. The designation is from the Mailyan
Dwarf Galaxy Catalogue. So apparently it is a small galaxy much closer
than the previously mentioned galaxies. Though without redshift data
this is only a guess.

Every object NED lists in the field has been annotated. Most with a ?
for distance. A few that would seem reasonable for NED to know about
aren't listed. Probably because those that are are either from the
2MASS catalog of 2 micron objects which omits galaxies without 2 micron
radiation which usually means lots of warm dust, or they are objects
with strong ultraviolet radiation. These are noted by UvES. Often
these are quasar candidates though they can be just stars with unusual
UV radiation and even galaxies. One that is certainly a galaxy is at
the top of the image left of center. The others are star-like but
without redshift data I can't tell if they might be quasar candidates or
not.

The entire field is full of IFN, galactic cirrus. Unfortunately my
color data is somewhat noisy do to clouds so it looks rather noisy.
This image was taken over a couple nights but still was severely hurt by
clouds. This is my last January 2012 image. Weather allowed me to
capture only 5 objects that month and most of those were taken under far
from ideal skies. February wasn't any better nor was most of the year.

Arp's image:
http://ned.ipac.caltech.edu/level5/A...big_arp80.jpeg

14" LX200R @ f/10, L=8x10' R=4x10' G=3x10' B=2x10', STL-11000XM,
Paramount ME

Rick
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