ASTRO: Arp 249

I've posted some rather interesting galaxies and galaxy groups of late,
this isn't one of them. I'm imaging all Arp Atlas entries I can reach
from my location so I have to take the duds as well as the winners.

Arp 249 is a pair of interacting galaxies known as UGC 12891. Arp put
this pair under his Appearance of Fission category. I've never figured
out if he really thought they were splitting or just gave that
appearance. He later decided quasars were ejected from galaxies but was
more mainstream at the time he put the atlas together. His comment
indicates he sees three galaxies here while catalogs only see two and a
plume or jet depending on who you read. Arp says: "Straight connection
from faint material on east to middle galaxy." Which he sees as the
appearance of fission I don't know. One note at NED refers to this
eastern plume as "arrow-like projection." So what is the condensation
in the plume? None of the catalogs at NED list it but I can see why Arp
considered it a third galaxy. The Sloan survey, nor any other general
survey covers this part of the sky so information is hard to find. NED
lists the distance to the two main condensations as 511 and 512 million
light years. While the pair are appear to be elliptical galaxies NED
doesn't even try to classify them.

Besides a dearth of information on Arp 249 that also applies to most of
the field. Only one other galaxy in the image has any red shift data
with the vast majority of the galaxies not even listed at NED. In fact
one of the few carries the note that it really is only a field star!
The edge on spiral without much of a dust lane northwest of Arp 249
that's above a rather bright blue star is PGC 00004. Since that catalog
starts at 0 hours right ascension this galaxy almost marks that point
being only 3" of time east of that line. NED classes it simply as
Spiral (written out not S as you'd expect. Red shift puts it at 188
million light years.

A dozen or so other galaxies in the field are in the 2MASX catalog of IR
galaxies but without even so much as a magnitude estimate. Apparently
no one looks very hard at this part of the sky.

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp249.jpeg

14" LX200R, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Interesting galaxy(s), these galaxies are more interesting than
typical galaxies in that each has a story to tell and the viewer can
hypothesize as much as he/she wants .

Speaking of duds (if such exist in astrophotography), I have numerous
duds on my web site, galaxies, neublae and planetaries that are too
small, too dim or acquired under conditions that raise questions
about my sanity.



On Sat, 13 Nov 2010 23:04:55 -0600, Rick Johnson
wrote:

I've posted some rather interesting galaxies and galaxy groups of late,
this isn't one of them. I'm imaging all Arp Atlas entries I can reach
from my location so I have to take the duds as well as the winners.

Arp 249 is a pair of interacting galaxies known as UGC 12891. Arp put
this pair under his Appearance of Fission category. I've never figured
out if he really thought they were splitting or just gave that
appearance. He later decided quasars were ejected from galaxies but was
more mainstream at the time he put the atlas together. His comment
indicates he sees three galaxies here while catalogs only see two and a
plume or jet depending on who you read. Arp says: "Straight connection
from faint material on east to middle galaxy." Which he sees as the
appearance of fission I don't know. One note at NED refers to this
eastern plume as "arrow-like projection." So what is the condensation
in the plume? None of the catalogs at NED list it but I can see why Arp
considered it a third galaxy. The Sloan survey, nor any other general
survey covers this part of the sky so information is hard to find. NED
lists the distance to the two main condensations as 511 and 512 million
light years. While the pair are appear to be elliptical galaxies NED
doesn't even try to classify them.

Besides a dearth of information on Arp 249 that also applies to most of
the field. Only one other galaxy in the image has any red shift data
with the vast majority of the galaxies not even listed at NED. In fact
one of the few carries the note that it really is only a field star!
The edge on spiral without much of a dust lane northwest of Arp 249
that's above a rather bright blue star is PGC 00004. Since that catalog
starts at 0 hours right ascension this galaxy almost marks that point
being only 3" of time east of that line. NED classes it simply as
Spiral (written out not S as you'd expect. Red shift puts it at 188
million light years.

A dozen or so other galaxies in the field are in the 2MASX catalog of IR
galaxies but without even so much as a magnitude estimate. Apparently
no one looks very hard at this part of the sky.

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp249.jpeg

14" LX200R, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

In article .com Rick
Johnson wrote:


I've posted some rather interesting galaxies and galaxy groups of late,
this isn't one of them. I'm imaging all Arp Atlas entries I can reach
from my location so I have to take the duds as well as the winners.

They're all interesting.
Thanks for posting.
Thanks to everyone who posts.
--

09=IX