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ASTRO: Arp 312



 
 
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  #1  
Old March 21st 10, 07:13 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: Arp 312

Arp 312 is a group of galaxies in northern Hercules located about 525
million light-years away. It falls under Arp's category Group
Character: Groups of Galaxies. There are several Arp galaxies in this
area northeast of M92. While the galaxies of Arp 312 have about the
color of elliptical galaxies they are a bit bluer than most leading me
to wonder if these were spirals and have interacted sufficiently to
eject their dust and gas so are turning into elliptical galaxies. I
find very little on this group so this is pure speculation on my part.

How many of the galaxies Arp considered to be in the group is also a bit
difficult to determine. NED seems to list only 2, the two northern ones
sharing a common halo of stars. Webb and Knipe include the bright
galaxy to the southwest. Arp included the one to the northeast by a
star in his photo. His comment reads; "Diffuse connection between
central members of the group." Obviously the two brighter members show
a common halo. Look closely and it extends to the southwestern one as
well. That would be 3 members not just "central" ones. So is Arp
referring only to the two with the obvious halo and considering the
northeast and southwestern ones members not sharing a "diffuse
connection?"

The three major galaxies a MCG+8-31-4, the southeastern one;
MCG+8-31-5, the largest of the group; and MCG+8-31-6 the easternmost
galaxy of the three. The one hiding behind the star to the northeast is
2MASX J16495421+4643284 a strong IR emitting galaxy. But that applies to
the other three as well as they too are in the 2MASX catalog which was
conducted at the 2 micron IR wavelength. I find red shift data only on
MCG+8-31-5. I'd assume the three in the MCG catalog are all about the
same distance due to the common halo. Most everything else in the area
is a mystery unfortunately. No one seems to even be trying to classify
any of the 4.

While this area has been surveyed by the Sloan project no red shift data
for the entire field was found in NED. There are lots of interesting
galaxies but while I can put names on them that is about all I can do so
I haven't bothered to prepare an annotated version. The bright star is
a 7th magnitude K2 star that gave me fits when processing this image.

Sloan image:
http://astronomerica.awardspace.com/.../MCG8-31-4.php

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp312.jpeg

Besides the normal full image I've attached a 2x cropped version.

14" LX200R @ f/10, L=4x10 RGB=2x10x3, 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".

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Name:	ARP312L4X10RGB2X10X3.jpg
Views:	378
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Name:	ARP312L4X10RGB2X10X3CROP2X.jpg
Views:	120
Size:	66.8 KB
ID:	2860  
  #2  
Old March 21st 10, 12:43 PM posted to alt.binaries.pictures.astro
Stefan Lilge
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Posts: 2,269
Default ASTRO: Arp 312

Rick,

lots of faint stuff in this image...

Stefan

"Rick Johnson" schrieb im Newsbeitrag
. com...
Arp 312 is a group of galaxies in northern Hercules located about 525
million light-years away. It falls under Arp's category Group
Character: Groups of Galaxies. There are several Arp galaxies in this
area northeast of M92. While the galaxies of Arp 312 have about the
color of elliptical galaxies they are a bit bluer than most leading me
to wonder if these were spirals and have interacted sufficiently to
eject their dust and gas so are turning into elliptical galaxies. I
find very little on this group so this is pure speculation on my part.

How many of the galaxies Arp considered to be in the group is also a bit
difficult to determine. NED seems to list only 2, the two northern ones
sharing a common halo of stars. Webb and Knipe include the bright
galaxy to the southwest. Arp included the one to the northeast by a
star in his photo. His comment reads; "Diffuse connection between
central members of the group." Obviously the two brighter members show
a common halo. Look closely and it extends to the southwestern one as
well. That would be 3 members not just "central" ones. So is Arp
referring only to the two with the obvious halo and considering the
northeast and southwestern ones members not sharing a "diffuse
connection?"

The three major galaxies a MCG+8-31-4, the southeastern one;
MCG+8-31-5, the largest of the group; and MCG+8-31-6 the easternmost
galaxy of the three. The one hiding behind the star to the northeast is
2MASX J16495421+4643284 a strong IR emitting galaxy. But that applies to
the other three as well as they too are in the 2MASX catalog which was
conducted at the 2 micron IR wavelength. I find red shift data only on
MCG+8-31-5. I'd assume the three in the MCG catalog are all about the
same distance due to the common halo. Most everything else in the area
is a mystery unfortunately. No one seems to even be trying to classify
any of the 4.

While this area has been surveyed by the Sloan project no red shift data
for the entire field was found in NED. There are lots of interesting
galaxies but while I can put names on them that is about all I can do so
I haven't bothered to prepare an annotated version. The bright star is
a 7th magnitude K2 star that gave me fits when processing this image.

Sloan image:
http://astronomerica.awardspace.com/.../MCG8-31-4.php

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp312.jpeg

Besides the normal full image I've attached a 2x cropped version.

14" LX200R @ f/10, L=4x10 RGB=2x10x3, 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".



  #3  
Old March 24th 10, 01:25 AM posted to alt.binaries.pictures.astro
Richard Crisp[_1_]
external usenet poster
 
Posts: 985
Default ASTRO: Arp 312

Your clusters are always cool Rick

that's a very clean background too.

nice image!


"Rick Johnson" wrote in message
. com...
Arp 312 is a group of galaxies in northern Hercules located about 525
million light-years away. It falls under Arp's category Group
Character: Groups of Galaxies. There are several Arp galaxies in this
area northeast of M92. While the galaxies of Arp 312 have about the
color of elliptical galaxies they are a bit bluer than most leading me
to wonder if these were spirals and have interacted sufficiently to
eject their dust and gas so are turning into elliptical galaxies. I
find very little on this group so this is pure speculation on my part.

How many of the galaxies Arp considered to be in the group is also a bit
difficult to determine. NED seems to list only 2, the two northern ones
sharing a common halo of stars. Webb and Knipe include the bright
galaxy to the southwest. Arp included the one to the northeast by a
star in his photo. His comment reads; "Diffuse connection between
central members of the group." Obviously the two brighter members show
a common halo. Look closely and it extends to the southwestern one as
well. That would be 3 members not just "central" ones. So is Arp
referring only to the two with the obvious halo and considering the
northeast and southwestern ones members not sharing a "diffuse
connection?"

The three major galaxies a MCG+8-31-4, the southeastern one;
MCG+8-31-5, the largest of the group; and MCG+8-31-6 the easternmost
galaxy of the three. The one hiding behind the star to the northeast is
2MASX J16495421+4643284 a strong IR emitting galaxy. But that applies to
the other three as well as they too are in the 2MASX catalog which was
conducted at the 2 micron IR wavelength. I find red shift data only on
MCG+8-31-5. I'd assume the three in the MCG catalog are all about the
same distance due to the common halo. Most everything else in the area
is a mystery unfortunately. No one seems to even be trying to classify
any of the 4.

While this area has been surveyed by the Sloan project no red shift data
for the entire field was found in NED. There are lots of interesting
galaxies but while I can put names on them that is about all I can do so
I haven't bothered to prepare an annotated version. The bright star is
a 7th magnitude K2 star that gave me fits when processing this image.

Sloan image:
http://astronomerica.awardspace.com/.../MCG8-31-4.php

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp312.jpeg

Besides the normal full image I've attached a 2x cropped version.

14" LX200R @ f/10, L=4x10 RGB=2x10x3, 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".



 




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