ASTRO: Arp 99

Arp 99 is in Arp's class "spiral galaxies with E galaxy companions on
arms". I found this rather odd comment by him considering his
classification of it; "Connection not seen, but note difference in arms
toward and away from E galaxy. Note also material between preceding
spiral and E galaxy." He couldn't see any connecting arm yet it is
classed as if such a connection was there. I'm confused!

In any case it is a triple galaxy group consisting of NGC 7547 on the
right, NGC 7549 the two unequal arm spiral at the top and NGC 7550 the
highly torn apart elliptical. The system is about 200 million light
years away. Red shift puts them at 202, 201 and 215 million light-years
distant respectively. That would seem to put the distorted elliptical
well behind the other two. It's more likely that its really at about
the same distance but their relative motions create the apparent
discrepancy.

There appears to be a fourth member of the group, NGC 7558, down and
left of NGC 7550, but it is nearly 400 million light years distant so
not involved. It is a nice face on Sa spiral in any case. Well that's
what NED says. The NGC Project says E-S0 NGC 7547 (R')SAB(s)0/a: pec
at NED or more simply SBa pec by the NGC project. I prefer this latter
classification. NGC 7579 is classed by NED as SB(s)cd pec with an
Active galactic Nuclei (AGN) type not specified. NGC project calls it
SBc pec. I prefer NED on this one. NGC 7550. NED classes NGC 7550 as
S0- with an AGN while the NGC Project says E-S0. I'd think it rated a
pec designation as well. The last NGC galaxy in the field is NGC 7553
due east of NGC 7549. It is classed by NED and the NGC Project as S0.
Finally, they agree!

This object is outside the SDSS area.

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp99.jpeg

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

Full and 1.5x enlarged crop images attached.

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".

Now I like that set a lot Rick

Geez you find the coolest galaxies to image

I need to get my long focal length cassegrain set up again!


"Rick Johnson" wrote in message
. com...
Arp 99 is in Arp's class "spiral galaxies with E galaxy companions on
arms". I found this rather odd comment by him considering his
classification of it; "Connection not seen, but note difference in arms
toward and away from E galaxy. Note also material between preceding
spiral and E galaxy." He couldn't see any connecting arm yet it is
classed as if such a connection was there. I'm confused!

In any case it is a triple galaxy group consisting of NGC 7547 on the
right, NGC 7549 the two unequal arm spiral at the top and NGC 7550 the
highly torn apart elliptical. The system is about 200 million light
years away. Red shift puts them at 202, 201 and 215 million light-years
distant respectively. That would seem to put the distorted elliptical
well behind the other two. It's more likely that its really at about
the same distance but their relative motions create the apparent
discrepancy.

There appears to be a fourth member of the group, NGC 7558, down and
left of NGC 7550, but it is nearly 400 million light years distant so
not involved. It is a nice face on Sa spiral in any case. Well that's
what NED says. The NGC Project says E-S0 NGC 7547 (R')SAB(s)0/a: pec
at NED or more simply SBa pec by the NGC project. I prefer this latter
classification. NGC 7579 is classed by NED as SB(s)cd pec with an
Active galactic Nuclei (AGN) type not specified. NGC project calls it
SBc pec. I prefer NED on this one. NGC 7550. NED classes NGC 7550 as
S0- with an AGN while the NGC Project says E-S0. I'd think it rated a
pec designation as well. The last NGC galaxy in the field is NGC 7553
due east of NGC 7549. It is classed by NED and the NGC Project as S0.
Finally, they agree!

This object is outside the SDSS area.

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp99.jpeg

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

Full and 1.5x enlarged crop images attached.

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".

Thank Harlton Arp and his cohorts back in the early 60's. I'm just
imaging his catalog -- that part of it I can reach from my latitude and
that isn't blocked by my Polaris Tree. I can't go above 70 degrees due
to that tree and another behind it. They are my Snow Fence though last
winter all snow came from the south not north so they were worthless.
Fortunately, we didn't get much snow compared to prior years.

In today's email a fellow in England (I think that's where he's at) sent
me a list of his pecular ones to add to my list of non Arp oddities.
Together that gives me about 200 more to work on.

I'm beginning to think that there is no such thing as a "normal" galaxy
or maybe those few that are "normal" are really the outliers.

Rick

On 4/20/2010 8:39 PM, Richard Crisp wrote:
Now I like that set a lot Rick

Geez you find the coolest galaxies to image

I need to get my long focal length cassegrain set up again!


"Rick wrote in message
. com...
Arp 99 is in Arp's class "spiral galaxies with E galaxy companions on
arms". I found this rather odd comment by him considering his
classification of it; "Connection not seen, but note difference in arms
toward and away from E galaxy. Note also material between preceding
spiral and E galaxy." He couldn't see any connecting arm yet it is
classed as if such a connection was there. I'm confused!

In any case it is a triple galaxy group consisting of NGC 7547 on the
right, NGC 7549 the two unequal arm spiral at the top and NGC 7550 the
highly torn apart elliptical. The system is about 200 million light
years away. Red shift puts them at 202, 201 and 215 million light-years
distant respectively. That would seem to put the distorted elliptical
well behind the other two. It's more likely that its really at about
the same distance but their relative motions create the apparent
discrepancy.

There appears to be a fourth member of the group, NGC 7558, down and
left of NGC 7550, but it is nearly 400 million light years distant so
not involved. It is a nice face on Sa spiral in any case. Well that's
what NED says. The NGC Project says E-S0 NGC 7547 (R')SAB(s)0/a: pec
at NED or more simply SBa pec by the NGC project. I prefer this latter
classification. NGC 7579 is classed by NED as SB(s)cd pec with an
Active galactic Nuclei (AGN) type not specified. NGC project calls it
SBc pec. I prefer NED on this one. NGC 7550. NED classes NGC 7550 as
S0- with an AGN while the NGC Project says E-S0. I'd think it rated a
pec designation as well. The last NGC galaxy in the field is NGC 7553
due east of NGC 7549. It is classed by NED and the NGC Project as S0.
Finally, they agree!

This object is outside the SDSS area.

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp99.jpeg

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

Full and 1.5x enlarged crop images attached.

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".

Now that's a great group. At first I read "M99" instead of "Arp99". I wonder
if M99 is also in Arp's catalogue, it looks a bit strange too.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
. com...
Arp 99 is in Arp's class "spiral galaxies with E galaxy companions on
arms". I found this rather odd comment by him considering his
classification of it; "Connection not seen, but note difference in arms
toward and away from E galaxy. Note also material between preceding
spiral and E galaxy." He couldn't see any connecting arm yet it is
classed as if such a connection was there. I'm confused!

In any case it is a triple galaxy group consisting of NGC 7547 on the
right, NGC 7549 the two unequal arm spiral at the top and NGC 7550 the
highly torn apart elliptical. The system is about 200 million light
years away. Red shift puts them at 202, 201 and 215 million light-years
distant respectively. That would seem to put the distorted elliptical
well behind the other two. It's more likely that its really at about
the same distance but their relative motions create the apparent
discrepancy.

There appears to be a fourth member of the group, NGC 7558, down and
left of NGC 7550, but it is nearly 400 million light years distant so
not involved. It is a nice face on Sa spiral in any case. Well that's
what NED says. The NGC Project says E-S0 NGC 7547 (R')SAB(s)0/a: pec
at NED or more simply SBa pec by the NGC project. I prefer this latter
classification. NGC 7579 is classed by NED as SB(s)cd pec with an
Active galactic Nuclei (AGN) type not specified. NGC project calls it
SBc pec. I prefer NED on this one. NGC 7550. NED classes NGC 7550 as
S0- with an AGN while the NGC Project says E-S0. I'd think it rated a
pec designation as well. The last NGC galaxy in the field is NGC 7553
due east of NGC 7549. It is classed by NED and the NGC Project as S0.
Finally, they agree!

This object is outside the SDSS area.

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp99.jpeg

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

Full and 1.5x enlarged crop images attached.

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".

M99 isn't on his list, M90 and 101 are. 99 Sure looks to my eye to be a
"one heavy arm" candidate, more so than 101 but didn't make the list. I
don't know why. I too often get confused by Arp and M objects when
scanning my files. Once I was hunting for my Arp 192 file in the M
files until my brain finally realized why I couldn't find any above 110!
For a bit I thought something had wiped the files, even from the
backup drive. I'm getting old and senile it seems.

Rick

On 4/21/2010 2:53 PM, Stefan Lilge wrote:
Now that's a great group. At first I read "M99" instead of "Arp99". I wonder
if M99 is also in Arp's catalogue, it looks a bit strange too.

Stefan

"Rick schrieb im Newsbeitrag
. com...
Arp 99 is in Arp's class "spiral galaxies with E galaxy companions on
arms". I found this rather odd comment by him considering his
classification of it; "Connection not seen, but note difference in arms
toward and away from E galaxy. Note also material between preceding
spiral and E galaxy." He couldn't see any connecting arm yet it is
classed as if such a connection was there. I'm confused!

In any case it is a triple galaxy group consisting of NGC 7547 on the
right, NGC 7549 the two unequal arm spiral at the top and NGC 7550 the
highly torn apart elliptical. The system is about 200 million light
years away. Red shift puts them at 202, 201 and 215 million light-years
distant respectively. That would seem to put the distorted elliptical
well behind the other two. It's more likely that its really at about
the same distance but their relative motions create the apparent
discrepancy.

There appears to be a fourth member of the group, NGC 7558, down and
left of NGC 7550, but it is nearly 400 million light years distant so
not involved. It is a nice face on Sa spiral in any case. Well that's
what NED says. The NGC Project says E-S0 NGC 7547 (R')SAB(s)0/a: pec
at NED or more simply SBa pec by the NGC project. I prefer this latter
classification. NGC 7579 is classed by NED as SB(s)cd pec with an
Active galactic Nuclei (AGN) type not specified. NGC project calls it
SBc pec. I prefer NED on this one. NGC 7550. NED classes NGC 7550 as
S0- with an AGN while the NGC Project says E-S0. I'd think it rated a
pec designation as well. The last NGC galaxy in the field is NGC 7553
due east of NGC 7549. It is classed by NED and the NGC Project as S0.
Finally, they agree!

This object is outside the SDSS area.

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp99.jpeg

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

Full and 1.5x enlarged crop images attached.

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".