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NGC 0699 Is it Red and Dead?



 
 
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  #1  
Old April 14th 16, 07:38 AM
WA0CKY WA0CKY is offline
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Posts: 689
Default NGC 0699 Is it Red and Dead?

NGC 669 is a rather red and dead spiral in northwestern Triangulum. In fact the top third of the image is in Andromeda. It's located on the southwest corner of the Abell 262 galaxy cluster the core of which is sometimes known as "The Fath". It's redshift distance of 200 million light-years is within the range of redshifts seen for this cluster which is put at 220 million light-years. Tully-Fisher measurements put is distance at 250 million light-years but some of the papers indicate they had to make some rotation rate fudges due to weak signal from Ha sources so these readings may be off. The red and dead idea is supported by cold hydrogen data from radio telescopes. The galaxy is surrounded by a very large but very diffuse cloud of cold hydrogen. Hot hydrogen as evidenced by H alpha emission is also very weak. It appears much of its star building hydrogen has been thrown out of the galaxy. This could explain the lack of current star formation. The galaxy isn't distorted as if it had a major interaction to cause this but it may have been so long ago things are back to normal now but for the lack of star formation. Some of the red color may also be due to dust kicked out of the galaxy that is reddening it. Though I found nothing on this, just an idea I had. It also has an odd dust cloud along the rather dense dark lane which may be left over from some long ago interaction. If part of the Abell cluster it doesn't lack for candidates now well out of my field. The galaxy was discovered by Édouard Stephan on November 28, 1883. The galaxy is huge for a spiral with a diameter of about 185,000 light-years by my measurement. If the Tully-Fisher determination is right then it is 230,000 light-years across. Another reason to doubt that measurement.

The galaxy is listed in the 2 micron flat galaxy catalog. While not seen edge on the core region does give the appearance of being very flat. I suppose that is what allowed it to make the catalog as there's no optical evidence of a central bulge, just a very small and not all that bright core. Usually the bright core would be much larger and hide much of the far side of the galaxy due to its bulge. Thus if seen edge on this would likely be a very thin galaxy. Two other anonymous thin galaxies are in the image. One to the northwest and another possibly more distant one to the north northeast.

To the southeast is the double galaxy of UGC 01258. They appear connected by a tidal stream and neither has much structure left, if they had any to begin with. The southern and brighter part has a redshift that puts it at 190 million light-years so it too could be part of the Abell 262 cluster and likely related to NGC 669. Oddly the fainter northern galaxy is at the position the PGC has for this pair. I'd have expected the position to be between the two as it is for the UGC 1258 designation. The pair cover a projected distance of about 70,000 light-years. Assuming each ends at the middle of the tidal stream the northern galaxy is 28,000 light-years in size and the lower 42,000 light-years across.

The only other galaxy in the frame with redshift distance is [WGB2006] 014400+34320_e off the northeastern end of NGC 669 but at a distance of 1.3 billion light-years. It is about 80,000 light-years in size. I suspect several more of the galaxies in the image such as LEDA 3088490 is a member of the Abell 262 cluster but without redshift data that is only a guess.

The night I took this was very hazy causing nasty halos around even the fainter stars. I tried reducing the halos but that seems to have caused some stars to elongate in various directions probably due to where the haze halo was the brightest. I'm not sure it was worth the effort.

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

Rick
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  #2  
Old April 19th 16, 09:21 PM posted to alt.binaries.pictures.astro
Stefan Lilge
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Posts: 2,269
Default NGC 0699 Is it Red and Dead?

Rick,

the dust lane is very detailed in your picture in spite of the galaxies
small size. And the number of background galaxies is amazing.

Stefan

"WA0CKY" schrieb im Newsbeitrag ...


NGC 669 is a rather red and dead spiral in northwestern Triangulum. In
fact the top third of the image is in Andromeda. It's located on the
southwest corner of the Abell 262 galaxy cluster the core of which is
sometimes known as "The Fath". It's redshift distance of 200 million
light-years is within the range of redshifts seen for this cluster which
is put at 220 million light-years. Tully-Fisher measurements put is
distance at 250 million light-years but some of the papers indicate they
had to make some rotation rate fudges due to weak signal from Ha sources
so these readings may be off. The red and dead idea is supported by
cold hydrogen data from radio telescopes. The galaxy is surrounded by a
very large but very diffuse cloud of cold hydrogen. Hot hydrogen as
evidenced by H alpha emission is also very weak. It appears much of its
star building hydrogen has been thrown out of the galaxy. This could
explain the lack of current star formation. The galaxy isn't distorted
as if it had a major interaction to cause this but it may have been so
long ago things are back to normal now but for the lack of star
formation. Some of the red color may also be due to dust kicked out of
the galaxy that is reddening it. Though I found nothing on this, just
an idea I had. It also has an odd dust cloud along the rather dense
dark lane which may be left over from some long ago interaction. If
part of the Abell cluster it doesn't lack for candidates now well out of
my field. The galaxy was discovered by Édouard Stephan on November 28,
1883. The galaxy is huge for a spiral with a diameter of about 185,000
light-years by my measurement. If the Tully-Fisher determination is
right then it is 230,000 light-years across. Another reason to doubt
that measurement.

The galaxy is listed in the 2 micron flat galaxy catalog. While not
seen edge on the core region does give the appearance of being very
flat. I suppose that is what allowed it to make the catalog as there's
no optical evidence of a central bulge, just a very small and not all
that bright core. Usually the bright core would be much larger and hide
much of the far side of the galaxy due to its bulge. Thus if seen edge
on this would likely be a very thin galaxy. Two other anonymous thin
galaxies are in the image. One to the northwest and another possibly
more distant one to the north northeast.

To the southeast is the double galaxy of UGC 01258. They appear
connected by a tidal stream and neither has much structure left, if they
had any to begin with. The southern and brighter part has a redshift
that puts it at 190 million light-years so it too could be part of the
Abell 262 cluster and likely related to NGC 669. Oddly the fainter
northern galaxy is at the position the PGC has for this pair. I'd have
expected the position to be between the two as it is for the UGC 1258
designation. The pair cover a projected distance of about 70,000
light-years. Assuming each ends at the middle of the tidal stream the
northern galaxy is 28,000 light-years in size and the lower 42,000
light-years across.

The only other galaxy in the frame with redshift distance is [WGB2006]
014400+34320_e off the northeastern end of NGC 669 but at a distance of
1.3 billion light-years. It is about 80,000 light-years in size. I
suspect several more of the galaxies in the image such as LEDA 3088490
is a member of the Abell 262 cluster but without redshift data that is
only a guess.

The night I took this was very hazy causing nasty halos around even the
fainter stars. I tried reducing the halos but that seems to have caused
some stars to elongate in various directions probably due to where the
haze halo was the brightest. I'm not sure it was worth the effort.

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

Rick


--
WA0CKY

 




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