ASTRO: II Zw 073 Bet you've never seen this pair of galaxies

II Zw 073 is a very strange pair of galaxies in northeastern Bootes
about a quarter billion light-years from us. Individually they are UGC
9796 and MGC +07-31-049. At that distance you might not think there is
much to see but the western galaxy UGC 9796 is a polar ring galaxy with
a huge polar ring. While the galaxy itself is rather small with a
diameter of its spiral disk being 28,000 light-years across the polar
ring is about 115,000 light-years across. Its polar ring is 4 times the
size of the galaxy. A very strange situation indeed. The UGC's
original entry in 1973 reads: "Diffuse 'spindle' (dwarf?) with elongated
'core', probably superimposed companion". This was before polar ring
galaxies were really known so the confusion isn't surprising. More
surprising to me is that it is an entry in the Flat Galaxy Catalog! It
is listed in the addenda catalog as FGC 224A (the "A" identifies it as
an entry in the addenda catalog Apparently they are considering the
polar ring the plane of the galaxy. Even then the length is only about
4 times the width, not 7 times needed to make the FGC.

Its eastern companion, MCG +07-31-049 is listed as a starburst galaxy by
NED but lists no other classification for it. It too is a quarter
billion light-years away. There are several other galaxies in the image
at this distance. On is another flat galaxy, this one looks like it may
deserve the designation. It is FGC 225A, also from the addenda catalog.
CGCG 221-045 is a LINER galaxy. It has a companion, ASK 403585.0.
This pair is again a quarter of a billion light-years distant. In the
lower left corner is KISSR 1929. It appears to be a "Sloshed" galaxy".
These are galaxies with the core well off center. Usually this is
considered evidence of interaction with a much more massive galaxy.
However there isn't a nearby candidate that I found, even well out of my
field. Starburst, polar ring and LINER galaxies can all be indications
of prior interaction. With it being virtually certain in the case of a
polar ring galaxy. This group may have been a much tighter group in the
past allowing these interactions than we see today.

There are several quasars in the image, one closer than some of the
distant galaxies which is rather surprising. Two are labeled as BAL
quasars. This means they have broad absorption lines in their spectrum.
If you are curious about what this means it is explained rather well
in not too technical of terms at:
http://arxiv.org/ftp/astro-ph/papers/0610/0610656.pdf in the
introduction part of the paper. Those wanting more can read further.

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

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

Rick,

you certainly win this bet against me.
UGC 9796 reminds me of NGC 660 a lot, only _much_ smaller.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

II Zw 073 is a very strange pair of galaxies in northeastern Bootes
about a quarter billion light-years from us. Individually they are UGC
9796 and MGC +07-31-049. At that distance you might not think there is
much to see but the western galaxy UGC 9796 is a polar ring galaxy with
a huge polar ring. While the galaxy itself is rather small with a
diameter of its spiral disk being 28,000 light-years across the polar
ring is about 115,000 light-years across. Its polar ring is 4 times the
size of the galaxy. A very strange situation indeed. The UGC's
original entry in 1973 reads: "Diffuse 'spindle' (dwarf?) with elongated
'core', probably superimposed companion". This was before polar ring
galaxies were really known so the confusion isn't surprising. More
surprising to me is that it is an entry in the Flat Galaxy Catalog! It
is listed in the addenda catalog as FGC 224A (the "A" identifies it as
an entry in the addenda catalog Apparently they are considering the
polar ring the plane of the galaxy. Even then the length is only about
4 times the width, not 7 times needed to make the FGC.

Its eastern companion, MCG +07-31-049 is listed as a starburst galaxy by
NED but lists no other classification for it. It too is a quarter
billion light-years away. There are several other galaxies in the image
at this distance. On is another flat galaxy, this one looks like it may
deserve the designation. It is FGC 225A, also from the addenda catalog.
CGCG 221-045 is a LINER galaxy. It has a companion, ASK 403585.0.
This pair is again a quarter of a billion light-years distant. In the
lower left corner is KISSR 1929. It appears to be a "Sloshed" galaxy".
These are galaxies with the core well off center. Usually this is
considered evidence of interaction with a much more massive galaxy.
However there isn't a nearby candidate that I found, even well out of my
field. Starburst, polar ring and LINER galaxies can all be indications
of prior interaction. With it being virtually certain in the case of a
polar ring galaxy. This group may have been a much tighter group in the
past allowing these interactions than we see today.

There are several quasars in the image, one closer than some of the
distant galaxies which is rather surprising. Two are labeled as BAL
quasars. This means they have broad absorption lines in their spectrum.
If you are curious about what this means it is explained rather well
in not too technical of terms at:
http://arxiv.org/ftp/astro-ph/papers/0610/0610656.pdf in the
introduction part of the paper. Those wanting more can read further.

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

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