ASTRO: Arp 217 The Bow and Arrow Galaxy NGC 3310

Arp 217/NGC 3310 is an example of a galactic merger. There are two
cores separated by 2" of arc. Imaging at 1" per pixel I was unable to
resolve this. A tremendous spray of stars loops and radiates from this
galaxy. My 50 minutes of exposure time plus a nasty glare from a fifth
magnitude star just off the top of the frame made pulling it out
difficult. This galaxy is located in Ursa Major southwest of the
southwest corner of the bowl of the big dipper. It is about 50 million
light years distant by redshift measurement. Other sources put it
slightly further away but the differences are minor so I'll go with this
nice round number.

It is a starburst galaxy, possibly on par with M82. Oddly few O stars
are seen which is hard to explain. I was surprised by how much H alpha
I picked up in the arms. These huge regions indicate star formation is
going on not just in the core but along the arms as well. If O stars
are in short supply how are these regions being ionized?

It is known as the Bow and Arrow Galaxy for the odd stream of young blue
stars piercing a diffuse arc of stars that possibly traces the path of
the merging galaxy. I've also seen it called the Bowstring Galaxy
though that ignores the arrow so I prefer the former.

I had to place the galaxy high to move K3 giant star out of the field.
It still sent a halo of light through the upper half of the galaxy that
made processing this image very difficult. I lost some of the star
streams because of it.

I found some odd things while preparing the annotated image. First a
star-like object east of Arp 217 is identified as a star cluster
associated with Arp 217! It is labeled *Cl 0.05. Its redshift is the
same as that of Arp 217. That's one heck of a star cluster if that is
right.

Down to the southwest of Arp 217 is an object with three entries; the
primary as a star, next as an X ray source and lastly as a galaxy. But
it is listed as being 10.9 billion light years distant and is classed as
an AGN (Active Galactic Nuclei. That plus the X rays would make it a
quasar. I added a ? to its label for this reason.

In the lower right corner is the galaxy cluster GMBCG
J159.31485+53.30322 anchored by the Bright Cluster Galaxy GMBCG
J159.31485+53.30322 BCG. Measured redshift for the galaxy gives a
distance of 4.3 billion light-years. A photographic measurement of
redshift (less accurate) give a distance to the cluster of 4.1. I just
listed the 4.3 figure on the annotated image.

As us all to often the case I checked a galaxy that NED missed. It
found some 3000 within 20 minutes of Arp 217, half fainter than show on
my image. Yet it missed a rather red galaxy in the lower left corner
marked with a question mark. Usually these are low surface brightness
blue galaxies but in this case it is a pretty ordinary looking reddish
elliptical like galaxy.

This is a reshoot. The first time I tried imaging it the K3 star was in
the field and made such a glare across the entire image it was easier to
reshoot it than try to reprocess it. Still that star nailed me to some
extent. I doubt I'll try again however. This will have to do. I've
included a copy of the Sloan Digital Sky Survey image for reference.

14" LX200R @ f/10, L=5x10' RGB=2x10'x3, STL-11000XM, Paramount ME

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

Rick,

I think I have a b/w version of this galaxy.
Somehow the colour you got looks a bit strange to me. But so it does in the
SDSS image...

Stefan

"Rick Johnson" schrieb im Newsbeitrag
. com...
Arp 217/NGC 3310 is an example of a galactic merger. There are two
cores separated by 2" of arc. Imaging at 1" per pixel I was unable to
resolve this. A tremendous spray of stars loops and radiates from this
galaxy. My 50 minutes of exposure time plus a nasty glare from a fifth
magnitude star just off the top of the frame made pulling it out
difficult. This galaxy is located in Ursa Major southwest of the
southwest corner of the bowl of the big dipper. It is about 50 million
light years distant by redshift measurement. Other sources put it
slightly further away but the differences are minor so I'll go with this
nice round number.

It is a starburst galaxy, possibly on par with M82. Oddly few O stars
are seen which is hard to explain. I was surprised by how much H alpha
I picked up in the arms. These huge regions indicate star formation is
going on not just in the core but along the arms as well. If O stars
are in short supply how are these regions being ionized?

It is known as the Bow and Arrow Galaxy for the odd stream of young blue
stars piercing a diffuse arc of stars that possibly traces the path of
the merging galaxy. I've also seen it called the Bowstring Galaxy
though that ignores the arrow so I prefer the former.

I had to place the galaxy high to move K3 giant star out of the field.
It still sent a halo of light through the upper half of the galaxy that
made processing this image very difficult. I lost some of the star
streams because of it.

I found some odd things while preparing the annotated image. First a
star-like object east of Arp 217 is identified as a star cluster
associated with Arp 217! It is labeled *Cl 0.05. Its redshift is the
same as that of Arp 217. That's one heck of a star cluster if that is
right.

Down to the southwest of Arp 217 is an object with three entries; the
primary as a star, next as an X ray source and lastly as a galaxy. But
it is listed as being 10.9 billion light years distant and is classed as
an AGN (Active Galactic Nuclei. That plus the X rays would make it a
quasar. I added a ? to its label for this reason.

In the lower right corner is the galaxy cluster GMBCG
J159.31485+53.30322 anchored by the Bright Cluster Galaxy GMBCG
J159.31485+53.30322 BCG. Measured redshift for the galaxy gives a
distance of 4.3 billion light-years. A photographic measurement of
redshift (less accurate) give a distance to the cluster of 4.1. I just
listed the 4.3 figure on the annotated image.

As us all to often the case I checked a galaxy that NED missed. It
found some 3000 within 20 minutes of Arp 217, half fainter than show on
my image. Yet it missed a rather red galaxy in the lower left corner
marked with a question mark. Usually these are low surface brightness
blue galaxies but in this case it is a pretty ordinary looking reddish
elliptical like galaxy.

This is a reshoot. The first time I tried imaging it the K3 star was in
the field and made such a glare across the entire image it was easier to
reshoot it than try to reprocess it. Still that star nailed me to some
extent. I doubt I'll try again however. This will have to do. I've
included a copy of the Sloan Digital Sky Survey image for reference.

14" LX200R @ f/10, L=5x10' RGB=2x10'x3, STL-11000XM, Paramount ME

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

The strong magenta of the H alpha regions surprised me. I'd expect the
pink color. Think the blue of the O and B stars create this color when
combined with H alpha's red. Probably adding H alpha filter to the mix
would pink it up considerably. Something to try if I do it again.

The other issue is that K2 star. It put an orange glow across the
entire image. Not sure what removing that did to color balance. I
should see if eXcalibrator has enough good Sloan stars to use it as a
color reference. Too many image and so little processing time.

Rick

On 3/21/2012 3:27 PM, Stefan Lilge wrote:
Rick,

I think I have a b/w version of this galaxy.
Somehow the colour you got looks a bit strange to me. But so it does in the
SDSS image...

Stefan

"Rick schrieb im Newsbeitrag
. com...
Arp 217/NGC 3310 is an example of a galactic merger. There are two
cores separated by 2" of arc. Imaging at 1" per pixel I was unable to
resolve this. A tremendous spray of stars loops and radiates from this
galaxy. My 50 minutes of exposure time plus a nasty glare from a fifth
magnitude star just off the top of the frame made pulling it out
difficult. This galaxy is located in Ursa Major southwest of the
southwest corner of the bowl of the big dipper. It is about 50 million
light years distant by redshift measurement. Other sources put it
slightly further away but the differences are minor so I'll go with this
nice round number.

It is a starburst galaxy, possibly on par with M82. Oddly few O stars
are seen which is hard to explain. I was surprised by how much H alpha
I picked up in the arms. These huge regions indicate star formation is
going on not just in the core but along the arms as well. If O stars
are in short supply how are these regions being ionized?

It is known as the Bow and Arrow Galaxy for the odd stream of young blue
stars piercing a diffuse arc of stars that possibly traces the path of
the merging galaxy. I've also seen it called the Bowstring Galaxy
though that ignores the arrow so I prefer the former.

I had to place the galaxy high to move K3 giant star out of the field.
It still sent a halo of light through the upper half of the galaxy that
made processing this image very difficult. I lost some of the star
streams because of it.

I found some odd things while preparing the annotated image. First a
star-like object east of Arp 217 is identified as a star cluster
associated with Arp 217! It is labeled *Cl 0.05. Its redshift is the
same as that of Arp 217. That's one heck of a star cluster if that is
right.

Down to the southwest of Arp 217 is an object with three entries; the
primary as a star, next as an X ray source and lastly as a galaxy. But
it is listed as being 10.9 billion light years distant and is classed as
an AGN (Active Galactic Nuclei. That plus the X rays would make it a
quasar. I added a ? to its label for this reason.

In the lower right corner is the galaxy cluster GMBCG
J159.31485+53.30322 anchored by the Bright Cluster Galaxy GMBCG
J159.31485+53.30322 BCG. Measured redshift for the galaxy gives a
distance of 4.3 billion light-years. A photographic measurement of
redshift (less accurate) give a distance to the cluster of 4.1. I just
listed the 4.3 figure on the annotated image.

As us all to often the case I checked a galaxy that NED missed. It
found some 3000 within 20 minutes of Arp 217, half fainter than show on
my image. Yet it missed a rather red galaxy in the lower left corner
marked with a question mark. Usually these are low surface brightness
blue galaxies but in this case it is a pretty ordinary looking reddish
elliptical like galaxy.

This is a reshoot. The first time I tried imaging it the K3 star was in
the field and made such a glare across the entire image it was easier to
reshoot it than try to reprocess it. Still that star nailed me to some
extent. I doubt I'll try again however. This will have to do. I've
included a copy of the Sloan Digital Sky Survey image for reference.

14" LX200R @ f/10, L=5x10' RGB=2x10'x3, STL-11000XM, Paramount ME

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





--
Prefix is correct. Domain is arvig dot net