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ASTRO: Arp 297 Reprocessed



 
 
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Old June 12th 12, 08:12 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Default ASTRO: Arp 297 Reprocessed

I've been on a reprocessing binge the last few days. Nothing but high
winds and rain -- power was out several hours each of the last two days
due to trees across the power lines. Processing is about all I can do
without power. Boat's deep cycle battery runs the laptop at least. I
hope to get back to April 2011 objects soon as the power lets me on the
internet to research.

This image is only a a bit more than a year old, posted April 2011.
Still looking at it I knew I screwed up. Too dark by a mile and it
screamed to be displayed south up rather than my normal north at the
top. This is a complete redo but the text is copied from the old post.
________________
Arp 297 falls under Arp's category of galaxy groups, long filaments. It
is located in Bootes. It's distance is a problem I'll get to. It is
made up of several NGC galaxies, NGC 5752, 53, 54 and 55. When I looked
at Arp's image of it I was puzzled by his comment: "Companion on arm has
long tail extending westwards." The companion I assumed to be the
galaxy seen atop the spiral and while an arm of the spiral went behind
the "companion" I couldn't see that as being called a filament and it
certainly didn't go west (up in Arp's photo). Then I started to image
it. First 10 minute frame came in and there was a nasty reflection off
to the west of the spiral. I moved the scope as that would usually stop
such reflections. But there it was and it didn't move in relation to
the stars. So it might be real. I looked at the GIF version of the
POSS plates and saw a hint of something. I enhanced these and yes it
was there though my reflection was much larger. I downloaded the Sloan
image which showed it clearly and now I could see the real long filament
Arp was talking about. I can't see much hint of it in the scanned
version of his photo but sure could in my frames and the SDSS image. I
moved it back where it was for the first image and took 7 more. I
didn't use the moved frame as it would result in the image being rather
cropped by several minutes.

As I processed this image a year later I noticed something odd. The
filament goes west northwest then fades before appearing again going due
west at far higher intensity. Not only that there appears to be a faint
hint of it going further east than where it meets up with the west
northwest part. Also the color is different. This bothered me (still
does). Then I started to gather red shift data and things got really
strange. The spiral, NGC 5754, has a red shift of 215 million
light-years. The companion's redshift puts it at 214 million
light-years. So far so good. Now note the odd large blob on the arm
north and a bit east of the core of NGC 5754. That carries its own
catalog entry which NED labels as PoG meaning it's part of the galaxy.
But its red shift is more than twice as great putting it at 439 million
light-years. Oops that doesn't compute. Note it isn't blue as the rest
of the arm is but more white. The blue arm fades out before reaching it
in fact. Look back at the white part of the west pointing long filament
that's the same color. It points right to the blob! I have no idea if
this means anything or not but it sure is interesting! I find no entry
for the filament so can't provide a red shift.

Now consider the other two galaxies of the "group". NGC 5755 is the
highly distorted spiral and its redshift puts it 443 million light-years
away. About the same as the blob. The fourth galaxy is NGC 5753 to the
northwest of 5755. It's has a similar redshift that puts it at 442
million light-years. These are virtually the same as the blob
supposedly part of NGC 5754 yet at the distance of 5753 and 5755. Yet I
find no papers that see any issue here. Not even a mention of the
redshift differences. To me it is a really interesting puzzle.

At the bottom, a bit left of center, there's a galaxy cluster marked by
one enormous galaxy if NED's data is right. The cluster is MaxBCG
J221.37379+38.60317 and contains 15 galaxies in an unknown area that has
a photographically determined distance of 1.9 billion light years. The
core galaxy SDSS J144529.70+383611.4/2MASX J14452968+3836117 has a
redshift distance of 2.0 billion light-years. This is where I have a
big problem. If that's correct that is one tremendous galaxy. By my
measurement the galaxy is a bit over 53" of arc across which at that
distance is over a half million light-years. I had never considered a
galaxy of that size possible. NED shows it at magnitude 16.8 so there's
no chance of a misidentification though they show it as only 25 seconds
of arc across. Still twice the size of our galaxy but not impossible.
I can't see how they got that measurement however. My image scale is
1.01" per pixel so you can make your own measurement. I have to believe
something is wrong here, I just don't know what it is.

Arp's image
http://ned.ipac.caltech.edu/level5/A...ig_arp297.jpeg

14" LX200R @ f/10, L=8x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Rick

--
Prefix is correct. Domain is arvig dot net

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