ASTRO: Arp 109 Interacting galaxies

Arp 141 is a pair of interacting galaxies in Camelopardalis (a giraffe)
that had been too far north and lost in my now defunct Polaris trees. I
suspected it would make a spectacular image and it didn't disappoint.
The pair are 126 million light-years distant by redshift and 130 million
light-years by Tully Fisher measurement. A very close agreement. Arp
put it in his class for "material emanating from elliptical galaxies".
Arp had no comment on it so no way to tell if he really thought
something was emanating from the elliptical or just that it appeared to
be. In any case this is an obvious case of the elliptical tearing apart
a less massive and less dense spiral and suffering some collateral
damage in the process. It has a large plume to the north as well as a
plume to the south which is seen only because its red stars stand out
against the blue stars of the spiral. Here's a case where color makes a
plume obvious that wouldn't be seen visually in a black and white image
like Arp's. Spectroscopic measurements should detect the two very
different star populations. NED classes the elliptical as a ring galaxy
and the northern one as S0 pec rather than elliptical.

The pair is also known as UGC 3730. To the west is NGC 3705 classed as
S?. It has almost the same redshift as Arp 141 so is obviously part of
the same galaxy family. It shows some oddities so may also have
interacted with other members of its group. These are the only galaxies
with redshift data at NED. North of Arp 141 is the very odd galaxy KUG
0707+736. It is half red (southern half) and half very blue (northern
end). A note at NED says: "A giant HII region is at the northwest end."
Super hot O and B stars formed from this region are likely responsible
for the blue end. But what triggered such massive stars to form. The
galaxy is classed as Irregular?. Such galaxies often show massive star
formation when they've interacted with another though this isn't
required it is often the case. Without any redshift information it is
hard to tell if it is a member of the group or not. Most irregulars are
small so not likely much further away at least. About the only other
irregular galaxies of this type I can recall seeing are on the two
Hubble deep field images that look back at the fragments of galaxies in
our very early universe that merged to form the spiral and elliptical
galaxies we see today. Some are known to have escaped being lunch for a
major galaxy. Is this one of those?

In any case this turned out to be a very interesting field. Now, can I
survive all the snow that will dump on my observatory roof with the
trees gone? I lucked out last winter, virtually no snow. Doubt I'll be
so lucky this year.

This is my last September 2011 image so moving into October 2011 data.
Still over a year behind but that will change quickly as the weather
turned bad in October and stayed that way for over a year.

Arp's image:
http://ned.ipac.caltech.edu/level5/A...ig_arp141.jpeg

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

Rick
--
Prefix is correct. Domain is arvig dot net

I was told there was some odd things going on in the lower right corner. It appears one frame had odd faint reflections there I'd not noticed. I removed that part of that frame from the stack and reprocessed the full image. I hope this fixed the problem.

Rick

Wow, that galaxy really looks spectacular. I'd wish we had something similar
in our own local group.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
.com...

Arp 141 is a pair of interacting galaxies in Camelopardalis (a giraffe)
that had been too far north and lost in my now defunct Polaris trees. I
suspected it would make a spectacular image and it didn't disappoint.
The pair are 126 million light-years distant by redshift and 130 million
light-years by Tully Fisher measurement. A very close agreement. Arp
put it in his class for "material emanating from elliptical galaxies".
Arp had no comment on it so no way to tell if he really thought
something was emanating from the elliptical or just that it appeared to
be. In any case this is an obvious case of the elliptical tearing apart
a less massive and less dense spiral and suffering some collateral
damage in the process. It has a large plume to the north as well as a
plume to the south which is seen only because its red stars stand out
against the blue stars of the spiral. Here's a case where color makes a
plume obvious that wouldn't be seen visually in a black and white image
like Arp's. Spectroscopic measurements should detect the two very
different star populations. NED classes the elliptical as a ring galaxy
and the northern one as S0 pec rather than elliptical.

The pair is also known as UGC 3730. To the west is NGC 3705 classed as
S?. It has almost the same redshift as Arp 141 so is obviously part of
the same galaxy family. It shows some oddities so may also have
interacted with other members of its group. These are the only galaxies
with redshift data at NED. North of Arp 141 is the very odd galaxy KUG
0707+736. It is half red (southern half) and half very blue (northern
end). A note at NED says: "A giant HII region is at the northwest end."
Super hot O and B stars formed from this region are likely responsible
for the blue end. But what triggered such massive stars to form. The
galaxy is classed as Irregular?. Such galaxies often show massive star
formation when they've interacted with another though this isn't
required it is often the case. Without any redshift information it is
hard to tell if it is a member of the group or not. Most irregulars are
small so not likely much further away at least. About the only other
irregular galaxies of this type I can recall seeing are on the two
Hubble deep field images that look back at the fragments of galaxies in
our very early universe that merged to form the spiral and elliptical
galaxies we see today. Some are known to have escaped being lunch for a
major galaxy. Is this one of those?

In any case this turned out to be a very interesting field. Now, can I
survive all the snow that will dump on my observatory roof with the
trees gone? I lucked out last winter, virtually no snow. Doubt I'll be
so lucky this year.

This is my last September 2011 image so moving into October 2011 data.
Still over a year behind but that will change quickly as the weather
turned bad in October and stayed that way for over a year.

Arp's image:
http://ned.ipac.caltech.edu/level5/A...ig_arp141.jpeg

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

Rick
--
Prefix is correct. Domain is arvig dot net