ASTRO: Arp 12: a split arm galaxy

Arp 12, NGC 2608 is a "grand design" barred spiral about 110 million
light years away. The bar is short running nearly east to west so at
first glance it may appear not to have a bar. It is classed by Arp
under "Spiral galaxies: Split arm". In this case the arm on the western
side splits into three parts while the arm on the east (left) side is
normal. I took and am displaying the image at 0.5" per pixel rather
than my normal 1" per pixel. Seeing wasn't really up to it however so I
likely would have had better results using my normal 1" pixel. Only
thing is, looking at Arp's image it appears seeing on Mt. Palomar was
even worse than mine. Must go with imaging this galaxy. It was so poor
in fact that he couldn't tell if the second object in the galaxy was a
second core (due to a merger) or a star. His comment was; "Nucleus may
be double or superposed star." Even with my seeing it is obviously a
star. Though being able to image using color filters makes the task of
separating star from galaxy core much easier. In fact there's no sign
of any merger or disturbing galaxy. So why the one arm is split like it
is remains a mystery. You can see there is an outer halo to the galaxy
though such halos are rather common with most spiral galaxies if you
expose long enough. Still it is unusually bright and may have be due to
the same cause as the split arm, whatever that was.

There's not much else going on in this image. Only other galaxy of note
is to the northeast (upper left). It is trying to hide behind a field
star. It is SDSS J083526.71+283007.9 shining at a rather bright
magnitude 18.6. What's surprising is its red shift distance. That is
2.2 billion light years. It must be a spectacular sight to those no
farther from it than we are from Arp 12.

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp12.jpeg

14" LX200R @ f/10, L=8x10' RGB=2x10', STL-11000XM, Paramount ME
Image taken and displayed at 0.5" per pixel rather than my normal 1"

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Rick,

now that's a big one compared to your recent targets :-)
Although the 1x1 binning (or lack of binning) might be part of the game.
Very good detail in this unusual galaxy.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
ster.com...
Arp 12, NGC 2608 is a "grand design" barred spiral about 110 million
light years away. The bar is short running nearly east to west so at
first glance it may appear not to have a bar. It is classed by Arp
under "Spiral galaxies: Split arm". In this case the arm on the western
side splits into three parts while the arm on the east (left) side is
normal. I took and am displaying the image at 0.5" per pixel rather
than my normal 1" per pixel. Seeing wasn't really up to it however so I
likely would have had better results using my normal 1" pixel. Only
thing is, looking at Arp's image it appears seeing on Mt. Palomar was
even worse than mine. Must go with imaging this galaxy. It was so poor
in fact that he couldn't tell if the second object in the galaxy was a
second core (due to a merger) or a star. His comment was; "Nucleus may
be double or superposed star." Even with my seeing it is obviously a
star. Though being able to image using color filters makes the task of
separating star from galaxy core much easier. In fact there's no sign
of any merger or disturbing galaxy. So why the one arm is split like it
is remains a mystery. You can see there is an outer halo to the galaxy
though such halos are rather common with most spiral galaxies if you
expose long enough. Still it is unusually bright and may have be due to
the same cause as the split arm, whatever that was.

There's not much else going on in this image. Only other galaxy of note
is to the northeast (upper left). It is trying to hide behind a field
star. It is SDSS J083526.71+283007.9 shining at a rather bright
magnitude 18.6. What's surprising is its red shift distance. That is
2.2 billion light years. It must be a spectacular sight to those no
farther from it than we are from Arp 12.

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp12.jpeg

14" LX200R @ f/10, L=8x10' RGB=2x10', STL-11000XM, Paramount ME
Image taken and displayed at 0.5" per pixel rather than my normal 1"

Rick
--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".