Rick,

these two look like siamese twins. Unusual to have such similar partners in
a merger.
I guess now that you have those Arp galaxies you can turn to some more
exotic objects ;-)

Stefan


"WA0CKY" schrieb im Newsbeitrag ...


Arp 275/NGC 2881 is a pair of colliding galaxies in Hydra nearly a
quarter billion light-years from earth. Arp had no category for
colliding galaxies. Though he did have one for interacting galaxies.
Many dozen of his galaxies were interacting but only 6 made this
category, This was the first of the 6. Unlike most entries he had no
comment for this entry.

The two galaxies making up Arp 275 are also known as VV 293a and VV 293b
with VV 293a being the one on the left (east). It is the only one of
the pair to have redshift measurements. It isn't classified at NED
other than mention it has HII regions. VV 293b to the west is
classified at NED as Sbc? pec. A note at NED from the MCG catalog says;
"Bright, interacting. Two galaxies Fd in close contact with very large
deformations. A note with the VV catalog says; "On the (red) POSS print
the two major bodies are not in contact against the background of a
homogeneous disk." I can't tell from any image if they are in contact.
To me it appears that the eastern galaxy may be slightly in front of the
western one. Since I can't really tell where one galaxy ends and the
next begins I measure the long axis of the projected pair at about
74,000 light-years. So these aren't very big galaxies, even including
the plumes created by their interaction. The pair was discovered by
Lewis Swift on February 9, 1886 using a 16" refractor.

The only other galaxy in the image with any information is IC 2482 in
the southeast corner of my image. It is listed as an E+ at NED and much
closer than Arp 275 at about 175 million light-years. A note at NED
says of it; "The gradient of brightness in halo is smaller then in a
normal E." Oddly it is quite a bit brighter and larger in angular size
than Arp 275 yet wasn't discovered until March 14, 1899 by Herbert
Alonzo Howe using a 20" f/15 Alvan Clark-George Saegmuller refractor at
Chamberlin Observatory in Denver. How Swift missed it I don't know.
While it is partly off my frame I measured its the length of the side
fully on the frame and doubled that to get a size of 156,000
light-years. Twice the size of Arp 275. My sister-in-law lives in a
southern suburb of Denver and every time I've been there the seeing has
been awful. Seems like a poor place for an observatory from my sample.
The observatory is right in Denver only about 3 blocks east of the
University of Denver campus of which it is a part, right beside tennis
courts and ball diamond (both unlit last I knew). Conditions must have
been much better in 1899! It still is open two nights a week to show
the public the moon and planets, about all you can see from that
location today. Howe managed to find 60 IC objects from there. Not
much light pollution in his day.

Nothing else on the frame has any distance information useful for an
annotated image so I didn't prepare one.

This entry is likely my final Arp galaxy. What remain are either below
my horizon or mostly below the wall of the observatory. That's only 7 I
can't reach out of 338. I've been working on these now for nearly 10
years. Nice to finally be finished with them. Though a couple could
benefit from a reshoot under better conditions I don't see that
happening any time soon. I still have plenty of strange galaxies to
take that Arp didn't include. They will keep me busy for quite some
time.


14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick


--
WA0CKY