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ASTRO: NGC 7711 Don't mess with this galaxy, it will eat you up



 
 
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  #1  
Old August 26th 12, 07:31 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: NGC 7711 Don't mess with this galaxy, it will eat you up

NGC 7711 is located in Pegasus about 170 million light-years distant and
classed as S0 by both NED and the NGC Project. It is one odd galaxy
that Arp overlooked though it sure belongs in any list of peculiar
galaxies. Look at its core region and it is a pretty normal looking S0
type galaxy but on the right there's a blob that someone at Galaxy Zoo
decided made it a barred S0 galaxy. That appears to be wrong however.
Further right and down you see faint "debris". What is that? On the
left side appear to be two spiral arms but they don't appear on the
right side. Then right across the core of the galaxy is a fine dust
lane way out of plane for the "arms". How can all this explained. One
paper does have an explanation that accounts for much, but not all of
this. It covers several galaxies, this one begins on page 8.
http://arxiv.org/PS_cache/arxiv/pdf/...102.2905v1.pdf

Their explanation is that the "arms" are star trails from a dwarf
orbiting about the main galaxy in an eccentric orbit that passes well
away from the galaxy on the left side but near it on the right. We are
seeing two passes around the galaxy. The blob on the right is (closest
to the galaxy) the trails where they are compact on that side and the
dwarf itself (the part to the south) -- see the annotated image. They
don't mention the dust lane nor the "debris" to the southwest. I am
going to guess the dust lane is normal to the galaxy itself before this
encounter. Due to the encounter much of the dust has been expelled
leaving just a faint remnant of the original. The "debris" likely stars
expelled from both galaxies due to the encounter but mostly due to the
dwarf. That's my barely educated guess anyway.

UGC 12673 in the lower right corner is the only other galaxy of note.
It appears to have an off center nucleus. NED classes it one place as Sc
and another as Sdm.

There are three asteroids in the image. Two very faint. I've marked
them all in the annotated image. The bright one would normally have the
color frames barely showing after it but in this case the color data was
taken a different night when it was no longer in the frame.

There are several galaxy clusters in the frame with redshift determined
photographically. That's the P after the distance. The core galaxies
often had a different distance estimate. They too were photographically
determined. In one case the galaxy had no distance estimate so gets a
question mark.

(60357) 2000 AG96 is at magnitude 18.3
(298286) 2003 AG3 is at magnitude 20.1
(298506) 2003 VK9 shines at magnitude 20.2

Half the L data was taken on a night I was able to cool the camera 5C
further than the other night. This temperature difference changed my
image scale so normal aligning wouldn't work. Registar to the rescue.
It handled the two different image scales quite well. I ended up
processing the luminance channel twice as I didn't catch this the first
time. The difference was sufficient to show all stars at the left edge
as close doubles and highly elongated on the right side when aligned
normally. The difference between the warm and cool nights amounted to
about 8 pixels at the edges. I used the larger image scale as the
reference frame to avoid dark edges.

14" LX200R @ f/10, L=8x10' RGB=3x10', STL-11000XM, Paramount ME

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

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  #2  
Old August 26th 12, 08:51 PM
WA0CKY WA0CKY is offline
Senior Member
 
First recorded activity by SpaceBanter: Feb 2008
Posts: 689
Default

I see I had a typo in the annotated image moving a galaxy to 15 billion light-years. That's, of course, impossible. The universe is younger than that so light from that distance hasn't reached us as yet. Or I can image the hypothetical tachyon. It should be 1.5 billion light years. It has been corrected on the attached image.

Rick
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  #3  
Old August 27th 12, 10:23 PM posted to alt.binaries.pictures.astro
Stefan Lilge
external usenet poster
 
Posts: 2,269
Default ASTRO: NGC 7711 Don't mess with this galaxy, it will eat you up

Rick,

must have been a rather large dwarf to leave such a prominent trail :-)
Very interesting image.

Stefan

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

NGC 7711 is located in Pegasus about 170 million light-years distant and
classed as S0 by both NED and the NGC Project. It is one odd galaxy
that Arp overlooked though it sure belongs in any list of peculiar
galaxies. Look at its core region and it is a pretty normal looking S0
type galaxy but on the right there's a blob that someone at Galaxy Zoo
decided made it a barred S0 galaxy. That appears to be wrong however.
Further right and down you see faint "debris". What is that? On the
left side appear to be two spiral arms but they don't appear on the
right side. Then right across the core of the galaxy is a fine dust
lane way out of plane for the "arms". How can all this explained. One
paper does have an explanation that accounts for much, but not all of
this. It covers several galaxies, this one begins on page 8.
http://arxiv.org/PS_cache/arxiv/pdf/...102.2905v1.pdf

Their explanation is that the "arms" are star trails from a dwarf
orbiting about the main galaxy in an eccentric orbit that passes well
away from the galaxy on the left side but near it on the right. We are
seeing two passes around the galaxy. The blob on the right is (closest
to the galaxy) the trails where they are compact on that side and the
dwarf itself (the part to the south) -- see the annotated image. They
don't mention the dust lane nor the "debris" to the southwest. I am
going to guess the dust lane is normal to the galaxy itself before this
encounter. Due to the encounter much of the dust has been expelled
leaving just a faint remnant of the original. The "debris" likely stars
expelled from both galaxies due to the encounter but mostly due to the
dwarf. That's my barely educated guess anyway.

UGC 12673 in the lower right corner is the only other galaxy of note.
It appears to have an off center nucleus. NED classes it one place as Sc
and another as Sdm.

There are three asteroids in the image. Two very faint. I've marked
them all in the annotated image. The bright one would normally have the
color frames barely showing after it but in this case the color data was
taken a different night when it was no longer in the frame.

There are several galaxy clusters in the frame with redshift determined
photographically. That's the P after the distance. The core galaxies
often had a different distance estimate. They too were photographically
determined. In one case the galaxy had no distance estimate so gets a
question mark.

(60357) 2000 AG96 is at magnitude 18.3
(298286) 2003 AG3 is at magnitude 20.1
(298506) 2003 VK9 shines at magnitude 20.2

Half the L data was taken on a night I was able to cool the camera 5C
further than the other night. This temperature difference changed my
image scale so normal aligning wouldn't work. Registar to the rescue.
It handled the two different image scales quite well. I ended up
processing the luminance channel twice as I didn't catch this the first
time. The difference was sufficient to show all stars at the left edge
as close doubles and highly elongated on the right side when aligned
normally. The difference between the warm and cool nights amounted to
about 8 pixels at the edges. I used the larger image scale as the
reference frame to avoid dark edges.

14" LX200R @ f/10, L=8x10' RGB=3x10', STL-11000XM, Paramount ME

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

 




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