ASTRO: NGC 5905 and NGC 5908

NGC 5905 and 5908 are a pair of spiral galaxies in Draco less than a
degree north of Bootes. They are a bit under 160 million light-years
away. Most sources say they are not interacting. Though NGC 5905
certainly looks like it was tore up by some interaction in the recent
past. NED and the NGC Project classify NGC 5905 as SB(r)b;HII Sy1 and
SBb respectively. For NGC 5908 they both say Sb though one paper says
it could possibly be Sc based on its very small core. Assuming a
distance of about 155 million light years these are large spiral, NGC
5908 is about the size of our galaxy at 122,000 light-years. Measuring
the full extent of NGC 5905's distorted arms I get a size of 240,000
light-years making it an extremely large spiral though this is more due
to its distortion than its being very massive as spirals go. Prior to
being drawn out it likely was no larger than NGC 5908.

Most papers say NGC 5908 is very similar to the Sombrero Galaxy, M104.
I suppose this is due to the very small core and huge halo surrounding
he galaxy along with a very well defined dark lane. Though the halo
about M104 is far larger than the disk the disk of 5908 appears to be
slightly larger than the halo.

While NED says 5905 is a Seyfert 1 galaxy a note at NED disagrees saying
Seyfert 2 whose true nature is hidden by the HII emission. In any case
it certainly has an actively feeding black hole at its core. There were
to Tully-Fisher distance measurements at NED for NGC 5905 that place it
at about 140 million light-years. No non redshift measurements were
available for NGC 5908 that I found.

Look closely at the annotated image and you will find a couple dwarf
galaxies with similar redshifts showing they are members of the same
group. East of NGC 5908 is a pair of apparently interacting galaxies,
KUG 1515+556 at 370 million light-years. The northern member is very
blue and small but seems to have a large plume to the southwest. The
lower galaxy is far larger and redder. It too seems surrounded by a
plume of stars. At my resolution they appear to overlap. Sure wish we
could get a closer look at this pair. NED shows no papers about them.

There are several quasars in the image, two of which with redshifts
greater than 2. There are several galaxy clusters as well one with its
bright cluster galaxy visible at 5 billion light-years in my image. It
must be a huge and brilliant galaxy.

As usual, UvES objects are likely quasars but haven't been confirmed
spectroscopically with redshift being determined photometrically instead
as noted by a "p" after the distance.

This is my last May, 2012 object. June was a surprisingly good month
but due to its lack of dark time I need two nights to get an object.
Once in a while I got more than one but less than two. Still it was
twice as productive as February of 2012 or January and February this year.

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

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

Rick,

this is one of my favourite fields for late spring. You got a lot of detail
in this image.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

NGC 5905 and 5908 are a pair of spiral galaxies in Draco less than a
degree north of Bootes. They are a bit under 160 million light-years
away. Most sources say they are not interacting. Though NGC 5905
certainly looks like it was tore up by some interaction in the recent
past. NED and the NGC Project classify NGC 5905 as SB(r)b;HII Sy1 and
SBb respectively. For NGC 5908 they both say Sb though one paper says
it could possibly be Sc based on its very small core. Assuming a
distance of about 155 million light years these are large spiral, NGC
5908 is about the size of our galaxy at 122,000 light-years. Measuring
the full extent of NGC 5905's distorted arms I get a size of 240,000
light-years making it an extremely large spiral though this is more due
to its distortion than its being very massive as spirals go. Prior to
being drawn out it likely was no larger than NGC 5908.

Most papers say NGC 5908 is very similar to the Sombrero Galaxy, M104.
I suppose this is due to the very small core and huge halo surrounding
he galaxy along with a very well defined dark lane. Though the halo
about M104 is far larger than the disk the disk of 5908 appears to be
slightly larger than the halo.

While NED says 5905 is a Seyfert 1 galaxy a note at NED disagrees saying
Seyfert 2 whose true nature is hidden by the HII emission. In any case
it certainly has an actively feeding black hole at its core. There were
to Tully-Fisher distance measurements at NED for NGC 5905 that place it
at about 140 million light-years. No non redshift measurements were
available for NGC 5908 that I found.

Look closely at the annotated image and you will find a couple dwarf
galaxies with similar redshifts showing they are members of the same
group. East of NGC 5908 is a pair of apparently interacting galaxies,
KUG 1515+556 at 370 million light-years. The northern member is very
blue and small but seems to have a large plume to the southwest. The
lower galaxy is far larger and redder. It too seems surrounded by a
plume of stars. At my resolution they appear to overlap. Sure wish we
could get a closer look at this pair. NED shows no papers about them.

There are several quasars in the image, two of which with redshifts
greater than 2. There are several galaxy clusters as well one with its
bright cluster galaxy visible at 5 billion light-years in my image. It
must be a huge and brilliant galaxy.

As usual, UvES objects are likely quasars but haven't been confirmed
spectroscopically with redshift being determined photometrically instead
as noted by a "p" after the distance.

This is my last May, 2012 object. June was a surprisingly good month
but due to its lack of dark time I need two nights to get an object.
Once in a while I got more than one but less than two. Still it was
twice as productive as February of 2012 or January and February this year.

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

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