ASTRO: Arp 189 reshoot

I wasn't going to process this old image from May 2011 as it didn't
appear any better than an old version with far less data. But before
moving on to October 2011 images I decided to process it and see what
the difference was. I go into more detail at the end. Some of the text
below is a duplicate of my original post:
http://www.cloudynights.com/ubbthrea...1/Main/4426271

Arp 189/NGC 4651, the Umbrella Galaxy, is a member of the Virgo Cluster
of galaxies in the constellation of Coma Berenices. As such it is about
60 million light-years distant. So I'm a bit perplexed with its
coverage by NASA's Astronomical Picture of the Day entry for it. They
say it is 35 million light-years distant which removes it from the
cluster. It's redshift distance is about 51 million light-years while
NED lists many distance measurements by Tully-Fisher averaging about 85
million light-years and a Sosies measurement of 77 million light-years.
Nothing that I found agrees to APOD's 35 million light-year distance.
In other words does anyone really know its distance?

Arp put it in his category of galaxies with narrow filaments. His
comment reads: "Radio source near tail apparently not associated." We
now know that its odd structure is due to it eating another galaxy in
the recent past. The "narrow filament" is the remains of the galaxy
showing its path around the galaxy as it was torn apart by gravitational
tidal forces.

I prepared an annotated image as there were some very distant galaxies
on the east side of Arp 189. Probably on the other sides as well but
for some reason the Sloan survey only took redshift data mostly on a
very small area of my image. All of it on very distant galaxies and one
quasar. The quasar is closer than many of the galaxies! While my image
is poor in focus it did go deep anyway with galaxies down to 23rd
magnitude recorded. You may need to blow up the image to find some of
these very faint ones. When you do you will find the field jammed with
tiny faint fuzzy spots. I had thought this just background noise but
when I looked up the position of these 22nd magnitude and fainter
galaxies at 5 and even 6 billion light-years there was one of these
fuzzy blobs dead on the position. Most agreed to a few hundredths of a
second of arc. If off by more than the error circle of the SDSS data I
skipped it. Only happened once. In one 10" circle that I tested there
were 5 and every one had an entry in the catalog though only 1 had
redshift data. Thus, I'm quite sure these faint blobs (blow up the image
3x or more to see them) are distant galaxies.

One galaxy with redshift data and out of the concentrated area is LEDA
140003 in the lower left corner. NED gives it two entries with no
indication that they are duplicates. Both are listed in the 18th
magnitude range with positions less than 1 second of arc (less than one
pixel) different. The redshifts were slightly different as well. I've
listed both on the annotated image. There does appear to be a second
bright area that is below the core by three seconds of arc, far more
than the separation NED shows and in the wrong direction. Both are
listed with an position error circle of 1.25" of arc, more than the
difference. But this doesn't explain the difference in the radial
velocity measurement.

I've listed a few of the brighter galaxies that had no redshift data by
catalog name. This is followed by a question mark as the distances are
completely unknown.

This is a reshoot attempting to get more of the fainter plumes. While
it is 160 minutes, over three times longer than the first attempt at 50
minutes it really doesn't go any deeper nor show the plumes much better.
I don't begin to see the ~79% increase in signal to noise ratio the
math says I should see. The problem is the first was taken under better
average conditions. This nearly cancelled out the much greater time.
Seems to happen every time I try for a lot more time. Just doesn't seem
to help significantly so I stick to my standard 40 minutes of luminance
most of the time. Every now and then I try much more time but usually
with little improvement.

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp189.jpeg

APOD image much deeper than any of the above or mine with overlay of the
path of the doomed satellite galaxy:
http://apod.nasa.gov/apod/ap100415.html

14" LX200R @ f/10, L=16x10' RB=6x10' G=5x10', STL-11000XM, Paramount ME

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

Mighty image Rick. I put it on my list after seeing your old image, but
didn't manage to capture it yet.

Stefan

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

I wasn't going to process this old image from May 2011 as it didn't
appear any better than an old version with far less data. But before
moving on to October 2011 images I decided to process it and see what
the difference was. I go into more detail at the end. Some of the text
below is a duplicate of my original post:
http://www.cloudynights.com/ubbthrea...1/Main/4426271

Arp 189/NGC 4651, the Umbrella Galaxy, is a member of the Virgo Cluster
of galaxies in the constellation of Coma Berenices. As such it is about
60 million light-years distant. So I'm a bit perplexed with its
coverage by NASA's Astronomical Picture of the Day entry for it. They
say it is 35 million light-years distant which removes it from the
cluster. It's redshift distance is about 51 million light-years while
NED lists many distance measurements by Tully-Fisher averaging about 85
million light-years and a Sosies measurement of 77 million light-years.
Nothing that I found agrees to APOD's 35 million light-year distance.
In other words does anyone really know its distance?

Arp put it in his category of galaxies with narrow filaments. His
comment reads: "Radio source near tail apparently not associated." We
now know that its odd structure is due to it eating another galaxy in
the recent past. The "narrow filament" is the remains of the galaxy
showing its path around the galaxy as it was torn apart by gravitational
tidal forces.

I prepared an annotated image as there were some very distant galaxies
on the east side of Arp 189. Probably on the other sides as well but
for some reason the Sloan survey only took redshift data mostly on a
very small area of my image. All of it on very distant galaxies and one
quasar. The quasar is closer than many of the galaxies! While my image
is poor in focus it did go deep anyway with galaxies down to 23rd
magnitude recorded. You may need to blow up the image to find some of
these very faint ones. When you do you will find the field jammed with
tiny faint fuzzy spots. I had thought this just background noise but
when I looked up the position of these 22nd magnitude and fainter
galaxies at 5 and even 6 billion light-years there was one of these
fuzzy blobs dead on the position. Most agreed to a few hundredths of a
second of arc. If off by more than the error circle of the SDSS data I
skipped it. Only happened once. In one 10" circle that I tested there
were 5 and every one had an entry in the catalog though only 1 had
redshift data. Thus, I'm quite sure these faint blobs (blow up the image
3x or more to see them) are distant galaxies.

One galaxy with redshift data and out of the concentrated area is LEDA
140003 in the lower left corner. NED gives it two entries with no
indication that they are duplicates. Both are listed in the 18th
magnitude range with positions less than 1 second of arc (less than one
pixel) different. The redshifts were slightly different as well. I've
listed both on the annotated image. There does appear to be a second
bright area that is below the core by three seconds of arc, far more
than the separation NED shows and in the wrong direction. Both are
listed with an position error circle of 1.25" of arc, more than the
difference. But this doesn't explain the difference in the radial
velocity measurement.

I've listed a few of the brighter galaxies that had no redshift data by
catalog name. This is followed by a question mark as the distances are
completely unknown.

This is a reshoot attempting to get more of the fainter plumes. While
it is 160 minutes, over three times longer than the first attempt at 50
minutes it really doesn't go any deeper nor show the plumes much better.
I don't begin to see the ~79% increase in signal to noise ratio the
math says I should see. The problem is the first was taken under better
average conditions. This nearly cancelled out the much greater time.
Seems to happen every time I try for a lot more time. Just doesn't seem
to help significantly so I stick to my standard 40 minutes of luminance
most of the time. Every now and then I try much more time but usually
with little improvement.

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp189.jpeg

APOD image much deeper than any of the above or mine with overlay of the
path of the doomed satellite galaxy:
http://apod.nasa.gov/apod/ap100415.html

14" LX200R @ f/10, L=16x10' RB=6x10' G=5x10', STL-11000XM, Paramount ME

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