ASTRO: Arp 329 galaxy chain

Arp 329 aka Hickson 55 is yet another chain of elliptical galaxies Arp
logically put in his Group Character: Chains of galaxies class. Also
known as UGC 6514 1 through 5. This is a rather puzzling chain. 4 of
the galaxies show a red shift that puts them at about 700 million
light-years with only a very small variation, smaller than normally
found in such chains in fact. But then there's that oddball one. Can
you spot it?

Most catalogs list these under one number with either a letter A-E or
number 1-5 designating which is which. Since these are assigned in RA
order it is kind of confusing. Only the PGC catalog gives them separate
numbers but again in RA order. Top (north) to bottom they are PGC
035574, PGC 035576, PGC 035575, PGC 035573 and PGC 035572.

The odd galaxy out is the second from the top, PGC 035576. It is the
smallest and bluest of the bunch. It's red shift puts it a bit more
than twice as distant as the other four at about 1.5 billion
light-years. No wonder I pick up so little detail. So is it just a
line of sight coincidence or is it really much closer. Arp would likely
argue for the latter while most other astronomers the former. To me its
different color and its smaller size would cause me to vote with the
coincidence theory. Oddly, Arp seems to have no comment on this one.
Though he does state in general that he considered such a coincidence to
be a 1 in 10^4 to 1 in 10^6 chance level. I don't understand how he
came up with this however. Sounds to me to be calculating the chance in
a particular group for such a coincidence rather than the chance that
some groups will have such a coincidence. I know I have at least one
math prof on the list, maybe he has some ideas on this. Arp also
considered chains even without an oddball to be highly unlikely due to
chance. Now we know that in small groups gravity will tend to cause
them to fall into such chains. Also remember we are seeing this in 2D,
we really can't say much about the depth involved. Though the math now
says real chains should be about as common as we find them to be.

Very few of the galaxies in the image are in any catalog except the MAC
which gives little useful information. I find red shift data mostly
missing except for the Hickson group and one other.

The elliptical above and right of Arp 329 is 2MASX J11314875+7054045.
While it is the same color and about the same size and brightness of the
biggest member of the Arp group, without red shift data I can't tell if
it is a member or not. The blue spiral to the east (left) of Arp 329 is
MCG +12-11-033 at magnitude 17. The blue galaxy near the bottom edge a
bit left of Arp 329 is CGCG 334-036. East (left) of this galaxy is the
tiny S0 galaxy 2MASX J11340329+7035372 at about 125 million light-years
(much closer than Arp 329). The spiral to its upper left is 2MASX
J11344815+7039213. It appears there's a distant group of galaxies
behind it but I find nothing on them other than a couple are also IR
galaxies with no red shift data. The glue blob of a galaxy west of the
last galaxy and above the previous one is PGC 2737488 at 18th magnitude.
I could find no entry for the blue galaxy above and a bit left of Arp
329. I didn't check the MAC however.

The bright elongated, very bright, yellow star near the left edge is
Struve 1551, a double star the brighter is G5 and thus nearly white
since I balance to G2 being white. Its companion appears somewhat
yellower. They are separated by about 7" and thus overlap due to the
heavy stretch applied to the image.

Arp's image
http://nedwww.ipac.caltech.edu/level...ig_arp329.jpeg

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

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

Rick,

the great detail you achieved can be seen in the small spiral left of the
chain.
Actually there are two galaxies that stand out; while three of them are
yellow, one is white and one is red. Either of them must be the "odd" one
you were referring to.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
om...
Arp 329 aka Hickson 55 is yet another chain of elliptical galaxies Arp
logically put in his Group Character: Chains of galaxies class. Also
known as UGC 6514 1 through 5. This is a rather puzzling chain. 4 of
the galaxies show a red shift that puts them at about 700 million
light-years with only a very small variation, smaller than normally
found in such chains in fact. But then there's that oddball one. Can
you spot it?

Most catalogs list these under one number with either a letter A-E or
number 1-5 designating which is which. Since these are assigned in RA
order it is kind of confusing. Only the PGC catalog gives them separate
numbers but again in RA order. Top (north) to bottom they are PGC
035574, PGC 035576, PGC 035575, PGC 035573 and PGC 035572.

The odd galaxy out is the second from the top, PGC 035576. It is the
smallest and bluest of the bunch. It's red shift puts it a bit more
than twice as distant as the other four at about 1.5 billion
light-years. No wonder I pick up so little detail. So is it just a
line of sight coincidence or is it really much closer. Arp would likely
argue for the latter while most other astronomers the former. To me its
different color and its smaller size would cause me to vote with the
coincidence theory. Oddly, Arp seems to have no comment on this one.
Though he does state in general that he considered such a coincidence to
be a 1 in 10^4 to 1 in 10^6 chance level. I don't understand how he
came up with this however. Sounds to me to be calculating the chance in
a particular group for such a coincidence rather than the chance that
some groups will have such a coincidence. I know I have at least one
math prof on the list, maybe he has some ideas on this. Arp also
considered chains even without an oddball to be highly unlikely due to
chance. Now we know that in small groups gravity will tend to cause
them to fall into such chains. Also remember we are seeing this in 2D,
we really can't say much about the depth involved. Though the math now
says real chains should be about as common as we find them to be.

Very few of the galaxies in the image are in any catalog except the MAC
which gives little useful information. I find red shift data mostly
missing except for the Hickson group and one other.

The elliptical above and right of Arp 329 is 2MASX J11314875+7054045.
While it is the same color and about the same size and brightness of the
biggest member of the Arp group, without red shift data I can't tell if
it is a member or not. The blue spiral to the east (left) of Arp 329 is
MCG +12-11-033 at magnitude 17. The blue galaxy near the bottom edge a
bit left of Arp 329 is CGCG 334-036. East (left) of this galaxy is the
tiny S0 galaxy 2MASX J11340329+7035372 at about 125 million light-years
(much closer than Arp 329). The spiral to its upper left is 2MASX
J11344815+7039213. It appears there's a distant group of galaxies
behind it but I find nothing on them other than a couple are also IR
galaxies with no red shift data. The glue blob of a galaxy west of the
last galaxy and above the previous one is PGC 2737488 at 18th magnitude.
I could find no entry for the blue galaxy above and a bit left of Arp
329. I didn't check the MAC however.

The bright elongated, very bright, yellow star near the left edge is
Struve 1551, a double star the brighter is G5 and thus nearly white
since I balance to G2 being white. Its companion appears somewhat
yellower. They are separated by about 7" and thus overlap due to the
heavy stretch applied to the image.

Arp's image
http://nedwww.ipac.caltech.edu/level...ig_arp329.jpeg

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

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

The odd one is the second from the top. See my third paragraph.
Rick

Stefan Lilge wrote:
Rick,

the great detail you achieved can be seen in the small spiral left of the
chain.
Actually there are two galaxies that stand out; while three of them are
yellow, one is white and one is red. Either of them must be the "odd" one
you were referring to.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
om...
Arp 329 aka Hickson 55 is yet another chain of elliptical galaxies Arp
logically put in his Group Character: Chains of galaxies class. Also
known as UGC 6514 1 through 5. This is a rather puzzling chain. 4 of
the galaxies show a red shift that puts them at about 700 million
light-years with only a very small variation, smaller than normally
found in such chains in fact. But then there's that oddball one. Can
you spot it?

Most catalogs list these under one number with either a letter A-E or
number 1-5 designating which is which. Since these are assigned in RA
order it is kind of confusing. Only the PGC catalog gives them separate
numbers but again in RA order. Top (north) to bottom they are PGC
035574, PGC 035576, PGC 035575, PGC 035573 and PGC 035572.

The odd galaxy out is the second from the top, PGC 035576. It is the
smallest and bluest of the bunch. It's red shift puts it a bit more
than twice as distant as the other four at about 1.5 billion
light-years. No wonder I pick up so little detail. So is it just a
line of sight coincidence or is it really much closer. Arp would likely
argue for the latter while most other astronomers the former. To me its
different color and its smaller size would cause me to vote with the
coincidence theory. Oddly, Arp seems to have no comment on this one.
Though he does state in general that he considered such a coincidence to
be a 1 in 10^4 to 1 in 10^6 chance level. I don't understand how he
came up with this however. Sounds to me to be calculating the chance in
a particular group for such a coincidence rather than the chance that
some groups will have such a coincidence. I know I have at least one
math prof on the list, maybe he has some ideas on this. Arp also
considered chains even without an oddball to be highly unlikely due to
chance. Now we know that in small groups gravity will tend to cause
them to fall into such chains. Also remember we are seeing this in 2D,
we really can't say much about the depth involved. Though the math now
says real chains should be about as common as we find them to be.

Very few of the galaxies in the image are in any catalog except the MAC
which gives little useful information. I find red shift data mostly
missing except for the Hickson group and one other.

The elliptical above and right of Arp 329 is 2MASX J11314875+7054045.
While it is the same color and about the same size and brightness of the
biggest member of the Arp group, without red shift data I can't tell if
it is a member or not. The blue spiral to the east (left) of Arp 329 is
MCG +12-11-033 at magnitude 17. The blue galaxy near the bottom edge a
bit left of Arp 329 is CGCG 334-036. East (left) of this galaxy is the
tiny S0 galaxy 2MASX J11340329+7035372 at about 125 million light-years
(much closer than Arp 329). The spiral to its upper left is 2MASX
J11344815+7039213. It appears there's a distant group of galaxies
behind it but I find nothing on them other than a couple are also IR
galaxies with no red shift data. The glue blob of a galaxy west of the
last galaxy and above the previous one is PGC 2737488 at 18th magnitude.
I could find no entry for the blue galaxy above and a bit left of Arp
329. I didn't check the MAC however.

The bright elongated, very bright, yellow star near the left edge is
Struve 1551, a double star the brighter is G5 and thus nearly white
since I balance to G2 being white. Its companion appears somewhat
yellower. They are separated by about 7" and thus overlap due to the
heavy stretch applied to the image.

Arp's image
http://nedwww.ipac.caltech.edu/level...ig_arp329.jpeg

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

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

sweet shot...


"Rick Johnson" wrote in message
om...
Arp 329 aka Hickson 55 is yet another chain of elliptical galaxies Arp
logically put in his Group Character: Chains of galaxies class. Also
known as UGC 6514 1 through 5. This is a rather puzzling chain. 4 of
the galaxies show a red shift that puts them at about 700 million
light-years with only a very small variation, smaller than normally
found in such chains in fact. But then there's that oddball one. Can
you spot it?

Most catalogs list these under one number with either a letter A-E or
number 1-5 designating which is which. Since these are assigned in RA
order it is kind of confusing. Only the PGC catalog gives them separate
numbers but again in RA order. Top (north) to bottom they are PGC
035574, PGC 035576, PGC 035575, PGC 035573 and PGC 035572.

The odd galaxy out is the second from the top, PGC 035576. It is the
smallest and bluest of the bunch. It's red shift puts it a bit more
than twice as distant as the other four at about 1.5 billion
light-years. No wonder I pick up so little detail. So is it just a
line of sight coincidence or is it really much closer. Arp would likely
argue for the latter while most other astronomers the former. To me its
different color and its smaller size would cause me to vote with the
coincidence theory. Oddly, Arp seems to have no comment on this one.
Though he does state in general that he considered such a coincidence to
be a 1 in 10^4 to 1 in 10^6 chance level. I don't understand how he
came up with this however. Sounds to me to be calculating the chance in
a particular group for such a coincidence rather than the chance that
some groups will have such a coincidence. I know I have at least one
math prof on the list, maybe he has some ideas on this. Arp also
considered chains even without an oddball to be highly unlikely due to
chance. Now we know that in small groups gravity will tend to cause
them to fall into such chains. Also remember we are seeing this in 2D,
we really can't say much about the depth involved. Though the math now
says real chains should be about as common as we find them to be.

Very few of the galaxies in the image are in any catalog except the MAC
which gives little useful information. I find red shift data mostly
missing except for the Hickson group and one other.

The elliptical above and right of Arp 329 is 2MASX J11314875+7054045.
While it is the same color and about the same size and brightness of the
biggest member of the Arp group, without red shift data I can't tell if
it is a member or not. The blue spiral to the east (left) of Arp 329 is
MCG +12-11-033 at magnitude 17. The blue galaxy near the bottom edge a
bit left of Arp 329 is CGCG 334-036. East (left) of this galaxy is the
tiny S0 galaxy 2MASX J11340329+7035372 at about 125 million light-years
(much closer than Arp 329). The spiral to its upper left is 2MASX
J11344815+7039213. It appears there's a distant group of galaxies
behind it but I find nothing on them other than a couple are also IR
galaxies with no red shift data. The glue blob of a galaxy west of the
last galaxy and above the previous one is PGC 2737488 at 18th magnitude.
I could find no entry for the blue galaxy above and a bit left of Arp
329. I didn't check the MAC however.

The bright elongated, very bright, yellow star near the left edge is
Struve 1551, a double star the brighter is G5 and thus nearly white
since I balance to G2 being white. Its companion appears somewhat
yellower. They are separated by about 7" and thus overlap due to the
heavy stretch applied to the image.

Arp's image
http://nedwww.ipac.caltech.edu/level...ig_arp329.jpeg

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

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".