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ASTRO: NGC 3447



 
 
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  #1  
Old May 28th 12, 07:27 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: NGC 3447

NGC 3447 is a pair of interacting galaxies in Leo about 65 to 66 million
light-years away. NED classes the larger western galaxy as SAB(s)m pec
and the smaller eastern galaxy as IB(s)m PEC. A Tully-Fisher
measurement of them says 65.5 million light-years so there's unusually
close agreement. The eastern member is odd in that the western end is
full of bright knots of star formation while the eastern end is very
diffuse with no visible structure at all. A golden object is seen at
the NE edge of the western galaxy. NED shows it as an IR source in the
2MASS catalog and as an HII source in the Hodge+Kennicutt HII regions
catalog. While an HII region can harbor new stars and give off a lot of
IR the whole thing looks like a distant galaxy to me rather than an
object in NGC 3447a.

SDSS J105329.58+164359.6 the small blue smudge under NGC 3447 at a
redshift indicated distance of 63 MLY seems to be a separate dwarf
galaxy. NED shows no classification for it. The three form an
interesting triple system that has been little studied that I could find.

Near the right edge of my image on the center-line of the image is SDSS
J105215.04+164446.4, a IR strong galaxy seen edge on. The southern arm
is very finely defined. The northern one seems mostly missing! At 2.3
billion light-years it is tough to see much detail. Still to have a
south going arm that size means it is a very large galaxy. The half a
galaxy in my image measures 15.6" of arc which at 2.3 billion-light
years is 175,000 light-years. That's for its radius or 350,000 for the
diameter if the other half is still there. It is faintly seen but very
poorly defined. Why the difference?

WHL J105303.8+165221 is a galaxy cluster at 3.1 billion light years but
the Big Cluster Galaxy (BCG) at its heart is listed at 2.8 billion
light-years. A surprisingly large difference.

ABELL 1126:[QR95] E and ABELL 1126:[QR95] W are listed as two galaxies
in the Abell 1126 galaxy cluster with the same exact position but
slightly different redshift. I've listed it as G 1.1/1.2 for this
reason. To add to the confusion the position of these two? galaxies is
almost but not quite the same as the core of the galaxy they seem to
pertain to. NED gives the core the designation 2MASX
J10535025+1651022/PGC 32713 at 1.1 million light-years which is listed
as a spiral oddly enough and as the cD galaxy for the Abell 1226 group.
It certainly looks like an elliptical galaxy to me. All this
confusion about the cD galaxy for an Abell galaxy cluster seems odd to
me. To its southeast is SDSS J105400.83+164843.2, a real spiral that is
closer to the core of Abell 1126. Could these two entries be somewhat
mixed-up? That galaxy is not categorized by NED at all, odd given its
size, brightness and obvious spiral nature.

The Abell 1126 cluster is listed as being 30 minutes in diameter, of
richness class 1 (50-79 galaxies) and at a distance of 1.1 billion
light-years. The nearby galaxy cluster NSCS J105344+165124 may be part
of this cluster. it is said to contain 22 members in an unknown area.
It too is at 1.1 billion light-years. Another apparent piece of the
Abell cluster is WHL J105415.1+165134. All I see at its position is a
rather large and bright (magnitude 17.6) galaxy. It is only labeled with
the G/GC label. NED lists it as having 15 members in an undefined area.

GMBCG J163.19257+16.60930 is a galaxy cluster in the lower right part of
my image. It is listed with 65 members but with no size. It's position
is within 1" of the BCG for the cluster. The BCG's spectral redshift
puts it at 4.2 billion light-years. The photographic redshift for the
cluster says 4.1 billion light-years. To its southwest is another galaxy
cluster, NSCS J105243+163554. Nothing is seen at its center. It is
said to contain 27 galaxies at 4.4 billion light-years. No size is
given. WHL J105238.1+163600 is likely another name for this cluster
though with yet a different center and core galaxy though the two vary
by about 1" of arc. It too is 4.4 billion light-years and consists of
47 members in an undefined area. So are all three really one cluster?
In any case there's a lot of faint fuzzies in a band through the lower
right part of my image.

South of these clusters is GMBCG J163.18556+16.56924. The BCG's
redshift is from its spectrum while the cluster's redshift has been
photographically determined. This leads to to slightly different
distances both about 4.7 billion light-years. The cluster is said to
contain 17 members and again no size is given.

ZwCl 1051.4+1656 is a galaxy cluster centered south of Abell 1126 but
includes it as its diameter is listed at 67 minutes and containing 345
members. No distance is listed. The label is centered on its central
position though I see very little at that location.

SDSS J105237.45+164109.0 may be the most distant and faintest object
I've picked up in only a 40 minute exposure. NED lists its green
magnitude as 24.8 with a redshift of z=4.815960. That, by their 5 year
WMAP calculator, puts it at 12.5 billion light-years light travel time.
Looking at it on the Sloan images it is actually very red though
nothing came through on the color filters at this position, just too
much light loss in the filters. This color is not unexpected since the
wavelengths of its light are 5.8 times longer than when they left the
quasar 12.5 billion years ago. My chip is rather insensitive to red but
likely that is what made it visible in my image. You might need to
enlarge the image by a factor of 3 or 4 to see the faint smudge but it
is there and the center pixel is precisely at the correct position. It
is seen in all 4 sub exposures as well.

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

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

Attached Thumbnails
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Name:	NGC3447L4X10RGB2X10X3.JPG
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ID:	4105  Click image for larger version

Name:	NGC3447L4X10RGB2X10X3-ID.JPG
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  #2  
Old May 28th 12, 09:02 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
external usenet poster
 
Posts: 3,085
Default ASTRO: NGC 3447

Grabbed the wrong cropped image. I wanted the one enlarged to 0.67" per
pixel.
Rick
_________________________

On 5/28/2012 1:27 AM, Rick Johnson wrote:
NGC 3447 is a pair of interacting galaxies in Leo about 65 to 66 million
light-years away. NED classes the larger western galaxy as SAB(s)m pec
and the smaller eastern galaxy as IB(s)m PEC. A Tully-Fisher measurement
of them says 65.5 million light-years so there's unusually close
agreement. The eastern member is odd in that the western end is full of
bright knots of star formation while the eastern end is very diffuse
with no visible structure at all. A golden object is seen at the NE edge
of the western galaxy. NED shows it as an IR source in the 2MASS catalog
and as an HII source in the Hodge+Kennicutt HII regions catalog. While
an HII region can harbor new stars and give off a lot of IR the whole
thing looks like a distant galaxy to me rather than an object in NGC 3447a.

SDSS J105329.58+164359.6 the small blue smudge under NGC 3447 at a
redshift indicated distance of 63 MLY seems to be a separate dwarf
galaxy. NED shows no classification for it. The three form an
interesting triple system that has been little studied that I could find.

Near the right edge of my image on the center-line of the image is SDSS
J105215.04+164446.4, a IR strong galaxy seen edge on. The southern arm
is very finely defined. The northern one seems mostly missing! At 2.3
billion light-years it is tough to see much detail. Still to have a
south going arm that size means it is a very large galaxy. The half a
galaxy in my image measures 15.6" of arc which at 2.3 billion-light
years is 175,000 light-years. That's for its radius or 350,000 for the
diameter if the other half is still there. It is faintly seen but very
poorly defined. Why the difference?

WHL J105303.8+165221 is a galaxy cluster at 3.1 billion light years but
the Big Cluster Galaxy (BCG) at its heart is listed at 2.8 billion
light-years. A surprisingly large difference.

ABELL 1126:[QR95] E and ABELL 1126:[QR95] W are listed as two galaxies
in the Abell 1126 galaxy cluster with the same exact position but
slightly different redshift. I've listed it as G 1.1/1.2 for this
reason. To add to the confusion the position of these two? galaxies is
almost but not quite the same as the core of the galaxy they seem to
pertain to. NED gives the core the designation 2MASX
J10535025+1651022/PGC 32713 at 1.1 million light-years which is listed
as a spiral oddly enough and as the cD galaxy for the Abell 1226 group.
It certainly looks like an elliptical galaxy to me. All this confusion
about the cD galaxy for an Abell galaxy cluster seems odd to me. To its
southeast is SDSS J105400.83+164843.2, a real spiral that is closer to
the core of Abell 1126. Could these two entries be somewhat mixed-up?
That galaxy is not categorized by NED at all, odd given its size,
brightness and obvious spiral nature.

The Abell 1126 cluster is listed as being 30 minutes in diameter, of
richness class 1 (50-79 galaxies) and at a distance of 1.1 billion
light-years. The nearby galaxy cluster NSCS J105344+165124 may be part
of this cluster. it is said to contain 22 members in an unknown area. It
too is at 1.1 billion light-years. Another apparent piece of the Abell
cluster is WHL J105415.1+165134. All I see at its position is a rather
large and bright (magnitude 17.6) galaxy. It is only labeled with the
G/GC label. NED lists it as having 15 members in an undefined area.

GMBCG J163.19257+16.60930 is a galaxy cluster in the lower right part of
my image. It is listed with 65 members but with no size. It's position
is within 1" of the BCG for the cluster. The BCG's spectral redshift
puts it at 4.2 billion light-years. The photographic redshift for the
cluster says 4.1 billion light-years. To its southwest is another galaxy
cluster, NSCS J105243+163554. Nothing is seen at its center. It is said
to contain 27 galaxies at 4.4 billion light-years. No size is given. WHL
J105238.1+163600 is likely another name for this cluster though with yet
a different center and core galaxy though the two vary by about 1" of
arc. It too is 4.4 billion light-years and consists of 47 members in an
undefined area. So are all three really one cluster? In any case there's
a lot of faint fuzzies in a band through the lower right part of my image.

South of these clusters is GMBCG J163.18556+16.56924. The BCG's redshift
is from its spectrum while the cluster's redshift has been
photographically determined. This leads to to slightly different
distances both about 4.7 billion light-years. The cluster is said to
contain 17 members and again no size is given.

ZwCl 1051.4+1656 is a galaxy cluster centered south of Abell 1126 but
includes it as its diameter is listed at 67 minutes and containing 345
members. No distance is listed. The label is centered on its central
position though I see very little at that location.

SDSS J105237.45+164109.0 may be the most distant and faintest object
I've picked up in only a 40 minute exposure. NED lists its green
magnitude as 24.8 with a redshift of z=4.815960. That, by their 5 year
WMAP calculator, puts it at 12.5 billion light-years light travel time.
Looking at it on the Sloan images it is actually very red though nothing
came through on the color filters at this position, just too much light
loss in the filters. This color is not unexpected since the wavelengths
of its light are 5.8 times longer than when they left the quasar 12.5
billion years ago. My chip is rather insensitive to red but likely that
is what made it visible in my image. You might need to enlarge the image
by a factor of 3 or 4 to see the faint smudge but it is there and the
center pixel is precisely at the correct position. It is seen in all 4
sub exposures as well.

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Rick



--
Prefix is correct. Domain is arvig dot net

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Name:	NGC3447L4X10RGB2X10X3CROP150.JPG
Views:	250
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ID:	4108  
 




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