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ASTRO: Super peculiar galaxies Arp didn't include UGC 9560 and 9562



 
 
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  #1  
Old November 17th 13, 07:04 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
external usenet poster
 
Posts: 3,085
Default ASTRO: Super peculiar galaxies Arp didn't include UGC 9560 and 9562

UGC 9560 and UGC 9562 are a pair of widely separated apparently
interacting galaxies in the "kite" of Bootes. At least something has
left these two in a very strange way. They are about 65 million
light-years away by redshift and 75 million by other measurements.
While I can't get into Arp's mind I have to think he'd have included
this pair if he had known about them. Many in his atlas are far more
normal looking than this pair!

UGC 9560 has a very blue core, a warped disk and jets. The one going
west southwest above the warped disk is most obvious. While the core is
blue the disk is rather white. Somewhat the reverse you normally see.
There's a lot of hot new stars in its well defined core. One paper
describes it this way: "This object presents very elongated outer
isophotes and a conspicuous central star-forming region. Orthogonally to
the major axis, on opposite sides, we see two jetlike structures."
Besides its peculiar designation it is a BCDG with HII emission from
that blue core. BCDG stands for "Blue Compact Disk Galaxy". It
certainly is as it is only about 17,500 light-years across assuming the
closer distance and 20,000 at the further distance estimate.

UGC 9562 is even stranger looking. It is classed as peculiar with HII
emission. In this case the HII comes from the odd blue structures.
Ignore those and it looks like a simple S0 galaxy. Most references
refer to the blue knots as knots in jets. If jets, they do seem to
arise from its core. In the Sloan image they almost look like they form
a ring around the galaxy though if that were the case I'd think we'd see
them right through a rather dust free galaxy. I found nothing
explaining this very strange feature. It's normal looking disk stretches
about 18,000 light years at the closer distance and 21,000 if the more
distant estimate is used. Again quite small. The blue knots extend a
slightly lesser distance, 17,500 light-years or 20,000 at the further
distance, the same as UGC 9560. The projected separation from UGC 9560
is only 76,500 light-years or 88,000 light-years depending on distance.
Less that the diameter of our galaxy. So while they are of low mass
there may still be some interaction going on. Still this is the least
distance that could separate them. We don't know the separation in
three dimensional space so it could be much greater.

I was also drawn to this region for its abundance of galaxy clusters.
Unfortunately the poor transparency and not great seeing we've had much
of the past 18+ months meant I couldn't go as deep as I wanted so the
clusters don't show nearly as well as they would have under normal
conditions. I'll just refer you to the annotated image.

It's time to repeat my abbreviations on annotated images involving
galaxy clusters. Most will be labeled GC/G meaning both the cluster and
its anchoring Bright Cluster Galaxy have virtually the same coordinates
so I've used one label for both. I show the number of galaxies NED has
for the cluster and its diameter if available (none had that information
this time). The distance to the cluster is listed first. A "p" means
it was determined photographically rather than spectroscopically. One
is labeled "e" as it is an estimate. If the galaxy's distance is the
same and determined the same way it is omitted. If different it will be
shown. If there's no distance given for the galaxy then "na" is used
for not available. GC without /G is used when the cluster has no BCG.
In such cases a line will be drawn to the approximate position. NED
usually states the cluster's position to +/- 15" of arc so I have to be
approximate in such cases. Otherwise I'll use the BCG and put the label
immediately to its right. If that's not possible as the label would
cover up members of the cluster or overlap a previous label or be hard
to read due to passing over a bright star, a line will go from the label
to the BCG.

More quasars than usual are also found in the image. Since light travel
time distances I use are rather meaningless at their great distance I
also include the z value. This is a measure of how much the frequency
of the light has been stretched to longer wavelengths. A z of 1 means
the wavelength has doubled so all the light we are seeing was emitted in
the ultra-violet part of the spectrum. A z=2 means the wavelength as
tripled etc. The relationship of z to light travel time distance is not
linear so at high z values a large change in z can result in a rather
small increase in light travel time. The z value would hit infinity at
the time of the big bang so it must rise rapidly as the look back time
approaches this value, ~13.7 billion years.

I've included the Sloan image of this pair as the last attachment.

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

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

Attached Thumbnails
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Name:	UGC9562L4X10RGB2X10ID.JPG
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  #2  
Old November 19th 13, 10:16 PM posted to alt.binaries.pictures.astro
Stefan Lilge
external usenet poster
 
Posts: 2,269
Default ASTRO: Super peculiar galaxies Arp didn't include UGC 9560 and 9562

Rick,

I know the "super thin" category of galaxies, so these belong to the "super
strange" group.
I would have thought that the blue knots are a different galaxy, but what do
I know...

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

UGC 9560 and UGC 9562 are a pair of widely separated apparently
interacting galaxies in the "kite" of Bootes. At least something has
left these two in a very strange way. They are about 65 million
light-years away by redshift and 75 million by other measurements.
While I can't get into Arp's mind I have to think he'd have included
this pair if he had known about them. Many in his atlas are far more
normal looking than this pair!

UGC 9560 has a very blue core, a warped disk and jets. The one going
west southwest above the warped disk is most obvious. While the core is
blue the disk is rather white. Somewhat the reverse you normally see.
There's a lot of hot new stars in its well defined core. One paper
describes it this way: "This object presents very elongated outer
isophotes and a conspicuous central star-forming region. Orthogonally to
the major axis, on opposite sides, we see two jetlike structures."
Besides its peculiar designation it is a BCDG with HII emission from
that blue core. BCDG stands for "Blue Compact Disk Galaxy". It
certainly is as it is only about 17,500 light-years across assuming the
closer distance and 20,000 at the further distance estimate.

UGC 9562 is even stranger looking. It is classed as peculiar with HII
emission. In this case the HII comes from the odd blue structures.
Ignore those and it looks like a simple S0 galaxy. Most references
refer to the blue knots as knots in jets. If jets, they do seem to
arise from its core. In the Sloan image they almost look like they form
a ring around the galaxy though if that were the case I'd think we'd see
them right through a rather dust free galaxy. I found nothing
explaining this very strange feature. It's normal looking disk stretches
about 18,000 light years at the closer distance and 21,000 if the more
distant estimate is used. Again quite small. The blue knots extend a
slightly lesser distance, 17,500 light-years or 20,000 at the further
distance, the same as UGC 9560. The projected separation from UGC 9560
is only 76,500 light-years or 88,000 light-years depending on distance.
Less that the diameter of our galaxy. So while they are of low mass
there may still be some interaction going on. Still this is the least
distance that could separate them. We don't know the separation in
three dimensional space so it could be much greater.

I was also drawn to this region for its abundance of galaxy clusters.
Unfortunately the poor transparency and not great seeing we've had much
of the past 18+ months meant I couldn't go as deep as I wanted so the
clusters don't show nearly as well as they would have under normal
conditions. I'll just refer you to the annotated image.

It's time to repeat my abbreviations on annotated images involving
galaxy clusters. Most will be labeled GC/G meaning both the cluster and
its anchoring Bright Cluster Galaxy have virtually the same coordinates
so I've used one label for both. I show the number of galaxies NED has
for the cluster and its diameter if available (none had that information
this time). The distance to the cluster is listed first. A "p" means
it was determined photographically rather than spectroscopically. One
is labeled "e" as it is an estimate. If the galaxy's distance is the
same and determined the same way it is omitted. If different it will be
shown. If there's no distance given for the galaxy then "na" is used
for not available. GC without /G is used when the cluster has no BCG.
In such cases a line will be drawn to the approximate position. NED
usually states the cluster's position to +/- 15" of arc so I have to be
approximate in such cases. Otherwise I'll use the BCG and put the label
immediately to its right. If that's not possible as the label would
cover up members of the cluster or overlap a previous label or be hard
to read due to passing over a bright star, a line will go from the label
to the BCG.

More quasars than usual are also found in the image. Since light travel
time distances I use are rather meaningless at their great distance I
also include the z value. This is a measure of how much the frequency
of the light has been stretched to longer wavelengths. A z of 1 means
the wavelength has doubled so all the light we are seeing was emitted in
the ultra-violet part of the spectrum. A z=2 means the wavelength as
tripled etc. The relationship of z to light travel time distance is not
linear so at high z values a large change in z can result in a rather
small increase in light travel time. The z value would hit infinity at
the time of the big bang so it must rise rapidly as the look back time
approaches this value, ~13.7 billion years.

I've included the Sloan image of this pair as the last attachment.

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

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

 




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