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ASTRO: NGC 864



 
 
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  #1  
Old January 26th 12, 08:56 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
external usenet poster
 
Posts: 3,085
Default ASTRO: NGC 864

I have no idea why I imaged this galaxy. I can't find it in my to-do
list nor was it on my to process list until I found it doing some
housekeeping of the hard drive. It is a somewhat interesting barred
spiral in Cetus about 60 to 70 million light years distant so rather
close, by my standards.

I found the notes at NED oddly contradictory. One says: "Strong,
slightly curved bar..." while another says:
"The central oval forms a weak bar...". Strong or weak it does have a
bar. In spiral galaxies bars tend to feed dust and gas into and out of
the cores of galaxies. This can trigger star formation both in the core
and in the arms. This flow shows as a dark lane down the middle of the
bar. This dark flow channel is quite obvious in my image, especially in
the western bar. Often this flow results in starburst activity in the
core of the galaxy. While NED classes it as SAB(rs)c with no starburst
mention I found this odd note at NED. "There is a remarkably small
circumnuclear starburst ring with a radius of slightly less than 100 pc.
The blue light from this starburst appears to dominate the visible light
from the nucleus." Sounds like the core should appear blue but I sure
see no hint of it. In fact such starburst activity is usually hidden
behind dust creating an IR strong galaxy that would be picked up by the
2MASS and possibly the IRAS survey. Sure enough this galaxy is listed
in both. While the core is somewhat whiter than in many barred spiral
it is still on the red side in my and all color images I found of this
galaxy.

There is very little on the rest of the field however. The only other
galaxy with redshift data is NGC 0864 COM01. It is the small SO type
somewhat blue oval near the left edge of my image below NGC 0864. It
has a very similar redshift so likely is related to NGC 0864.

There are a ton of faint distant galaxies in this image. Unfortunately,
none have redshift data and only a few are even cataloged by NED. Two
galaxy clusters are noted in the image. I've marked their centers and
distance in billions of light-years. NSCS J021527+055458 below the
galaxy and 5.6 billion light-years away is listed as having 17 members
in an unknown area. NSCS J021440+055700 to the west at 3.12 billion
light-years is larger with 49 members but again no size is listed.
Quite a few faint fuzzies are seen around these two locations. Are they
members of the cluster? I don't know. NED didn't have sufficient data
available.

There are 5 "bright" asteroids in the image and several that I see in
the Luminance stack but buried in the noise too far to bring out. The
brightest, 2006 SM363 is listed as 19.1 magnitude. The rest are listed
between 19.7 and 20.2 though they seem rather similarly bright in the
image so I have some doubts about the Minor Planet Center's magnitude
estimates. For instance 2001 FS96 at magnitude 20.2 estimated has the
longest trail of all in the image yet is brighter than some with far
shorter trails.

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Rick


--
Prefix is correct. Domain is arvig dot net

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Name:	NGC864L4X10RGB2X10X3R-ID.JPG
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  #2  
Old February 6th 12, 08:44 PM posted to alt.binaries.pictures.astro
Stefan Lilge
external usenet poster
 
Posts: 2,269
Default ASTRO: NGC 864

Rick,

maybe you just intended to make a "pretty picture" :-)
If so you succeeded.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...
I have no idea why I imaged this galaxy. I can't find it in my to-do
list nor was it on my to process list until I found it doing some
housekeeping of the hard drive. It is a somewhat interesting barred
spiral in Cetus about 60 to 70 million light years distant so rather
close, by my standards.

I found the notes at NED oddly contradictory. One says: "Strong,
slightly curved bar..." while another says:
"The central oval forms a weak bar...". Strong or weak it does have a
bar. In spiral galaxies bars tend to feed dust and gas into and out of
the cores of galaxies. This can trigger star formation both in the core
and in the arms. This flow shows as a dark lane down the middle of the
bar. This dark flow channel is quite obvious in my image, especially in
the western bar. Often this flow results in starburst activity in the
core of the galaxy. While NED classes it as SAB(rs)c with no starburst
mention I found this odd note at NED. "There is a remarkably small
circumnuclear starburst ring with a radius of slightly less than 100 pc.
The blue light from this starburst appears to dominate the visible light
from the nucleus." Sounds like the core should appear blue but I sure
see no hint of it. In fact such starburst activity is usually hidden
behind dust creating an IR strong galaxy that would be picked up by the
2MASS and possibly the IRAS survey. Sure enough this galaxy is listed
in both. While the core is somewhat whiter than in many barred spiral
it is still on the red side in my and all color images I found of this
galaxy.

There is very little on the rest of the field however. The only other
galaxy with redshift data is NGC 0864 COM01. It is the small SO type
somewhat blue oval near the left edge of my image below NGC 0864. It
has a very similar redshift so likely is related to NGC 0864.

There are a ton of faint distant galaxies in this image. Unfortunately,
none have redshift data and only a few are even cataloged by NED. Two
galaxy clusters are noted in the image. I've marked their centers and
distance in billions of light-years. NSCS J021527+055458 below the
galaxy and 5.6 billion light-years away is listed as having 17 members
in an unknown area. NSCS J021440+055700 to the west at 3.12 billion
light-years is larger with 49 members but again no size is listed.
Quite a few faint fuzzies are seen around these two locations. Are they
members of the cluster? I don't know. NED didn't have sufficient data
available.

There are 5 "bright" asteroids in the image and several that I see in
the Luminance stack but buried in the noise too far to bring out. The
brightest, 2006 SM363 is listed as 19.1 magnitude. The rest are listed
between 19.7 and 20.2 though they seem rather similarly bright in the
image so I have some doubts about the Minor Planet Center's magnitude
estimates. For instance 2001 FS96 at magnitude 20.2 estimated has the
longest trail of all in the image yet is brighter than some with far
shorter trails.

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Rick


--
Prefix is correct. Domain is arvig dot net




 




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