ASTRO: Arp 330 in spite of the Aurora

I'd been hoping for a really good night to image this group. Finally we
had one and the northern lights turned on so bright you could read a
newspaper. I might as well have been imaging from downtown Chicago. I
ended up throwing out a third of the luminosity images and half of the
red, green and blue images keeping the best two. Still I had super
nasty gradients. Normally my background would be about 250 counts out
of 65,000 but this image was 14,000 at the upper left, falling to 8,000
near the lower right but then a huge ray or something popped up taking
the very lower right corner to 39,000! Thank goodness for
GradientXTerminator. It took several applications using various
techniques but I ended up with a usable but not great image. My biggest
worry is color balance after removing so many gradients. But I think
I'm rather close to being correct even though most of the galaxies seem
overly reddened.

Arp 330 is in Arp's class: Group Character: Chains of galaxies. One
note describes the group: "In a beautiful interconnected chain of six
red compacts [faintest m(pg) = 18.5] and one blue crescent shaped
post-eruptive compact: m(pg) = 16.5.

From North to south the 7 galaxies a
2MASX J16491727+5327127, no classification or red shift data, mag 17
2MASX J16491727+5327127, E0, 350 million light-years, magnitude 17
2MASX J16491130+5325573, E2 pec, 410 million light-years, magnitude 17
2MASX J16491152+5325113, E1, 410 million light-years , magnitude 15.6
2MASX J16491274+5324183, SBbc pec HII, 364 million light-years, mag 16
MCG +09-27-093 mag 19
2MASX J16490837+5323334, E2 pec, 400 million light-years, magnitude 16
2MASX J16490401+5322254 no data

Ok, that's 8. I included the last one as I'm not sure if it or MCG
+09-27-093 is the 7th galaxy. 2MASX J16490401+5322254 shows well in
Arp's photo and is a bright IR galaxy while MCG +09-27-093 is nicely
tucked between two obvious members but barely shows in Arp's photo. So
which is the 7th member most sources speak of?

The very red, large, barred spiral galaxy to the upper left corner is
2MASX J16501529+5333072, so yet another IR galaxy. It is apparently part
of the same group at 400 million light-years. It's red color seems to
fit the group as well. But it must be a much larger galaxy.

Within the main group is the lone highly distorted spiral. It isn't red
at all. In fact it has a rather large blue tidal area between the two
larger elliptical's halos. The blue area is faint but seems real. Thus
it must be interacting with the others and its redshift a poor indicator
of distance.

The only other galaxy with a red shift in the image is 2MASX
J16471357+5333403 in the upper right corner. It fits right in with the
others with a red shift distance of 380 million light-years.

Going NW of Arp 330 about 7 minutes you come to the center of the Zwicky
galaxy cluster ZwCl 1647.6+5337 NED shows it as having 157 members in a
diameter of nearly 2 degrees, far larger than my image. It shows a red
shift distance of -- you guessed it -- 400 million light-years. It
appears nearly all its members are very red.

I've identified many of the galaxies around Arp 130 on a separate image.
You might wonder about the galaxy at the top near a bright star. It
wasn't in NED or SIMBAD. The Sky identifies it as PGC 281743 at
magnitude 16.5. Apparently it is not a IR galaxy so was missed by the 2
micron survey that picked up most of the galaxies in the image. What
about the SHK galaxies? SHK stands for Shakhbazian Compact Groups.
Number 16 on the list includes Arp 330 and surrounding galaxies. Most
of the 2MASX galaxies are also members of the SHK 16 group. Those that
are members of SHK 16 but not 2MASX cataloged galaxies I identified by
their SHK 16 number. Arp 330 carries several other group designations
such as CGPG 1648.0+5331 and I Zw 167. Like the SHK group these may
contain more galaxies than Arp did, I didn't check this however.

Arp's image of Arp 330 is at:
http://nedwww.ipac.caltech.edu/level...ig_arp330.jpeg

Even with the problems of the aurora my image goes deeper than his which
surprised me.

Rick

That's a nice shot Rick and I like the little twisted one in the center

I think Gradient Exterminator is an essential tool, I use it for gradients
when I have them


You have the aurora, we get wildfires.... they are in business again :-(

That's a nice shot Rick and I like the little twisted one in the center

I think Gradient Exterminator is an essential tool, I use it for gradients
when I have them


You have the aurora, we get wildfires.... they are in business again :-(

Richard Crisp wrote:
That's a nice shot Rick and I like the little twisted one in the center

I think Gradient Exterminator is an essential tool, I use it for gradients
when I have them


You have the aurora, we get wildfires.... they are in business again :-(



Aurora don't burn down homes and observatories. But forest fires do and
we sure have those. This is a dry year but nothing like the last few so
fire danger is only high not HOLY #(%* as it has been in the past few years.

To me this galaxy chain is sort of a golden chain with that one twisted,
blue one, being the clasp.

I've tried all the tools for gradients and Russ's is by far the best and
simplest and fastest in its latest form.

Richard Crisp wrote:
That's a nice shot Rick and I like the little twisted one in the center

I think Gradient Exterminator is an essential tool, I use it for gradients
when I have them


You have the aurora, we get wildfires.... they are in business again :-(



Aurora don't burn down homes and observatories. But forest fires do and
we sure have those. This is a dry year but nothing like the last few so
fire danger is only high not HOLY #(%* as it has been in the past few years.

To me this galaxy chain is sort of a golden chain with that one twisted,
blue one, being the clasp.

I've tried all the tools for gradients and Russ's is by far the best and
simplest and fastest in its latest form.

Rick,

very good result in spite of those northerners :-)
Actually my favourite is the barred spiral to the upper left.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
. com...
I'd been hoping for a really good night to image this group. Finally we
had one and the northern lights turned on so bright you could read a
newspaper. I might as well have been imaging from downtown Chicago. I
ended up throwing out a third of the luminosity images and half of the
red, green and blue images keeping the best two. Still I had super
nasty gradients. Normally my background would be about 250 counts out
of 65,000 but this image was 14,000 at the upper left, falling to 8,000
near the lower right but then a huge ray or something popped up taking
the very lower right corner to 39,000! Thank goodness for
GradientXTerminator. It took several applications using various
techniques but I ended up with a usable but not great image. My biggest
worry is color balance after removing so many gradients. But I think
I'm rather close to being correct even though most of the galaxies seem
overly reddened.

Arp 330 is in Arp's class: Group Character: Chains of galaxies. One
note describes the group: "In a beautiful interconnected chain of six
red compacts [faintest m(pg) = 18.5] and one blue crescent shaped
post-eruptive compact: m(pg) = 16.5.

From North to south the 7 galaxies a
2MASX J16491727+5327127, no classification or red shift data, mag 17
2MASX J16491727+5327127, E0, 350 million light-years, magnitude 17
2MASX J16491130+5325573, E2 pec, 410 million light-years, magnitude 17
2MASX J16491152+5325113, E1, 410 million light-years , magnitude 15.6
2MASX J16491274+5324183, SBbc pec HII, 364 million light-years, mag 16
MCG +09-27-093 mag 19
2MASX J16490837+5323334, E2 pec, 400 million light-years, magnitude 16
2MASX J16490401+5322254 no data

Ok, that's 8. I included the last one as I'm not sure if it or MCG
+09-27-093 is the 7th galaxy. 2MASX J16490401+5322254 shows well in
Arp's photo and is a bright IR galaxy while MCG +09-27-093 is nicely
tucked between two obvious members but barely shows in Arp's photo. So
which is the 7th member most sources speak of?

The very red, large, barred spiral galaxy to the upper left corner is
2MASX J16501529+5333072, so yet another IR galaxy. It is apparently part
of the same group at 400 million light-years. It's red color seems to
fit the group as well. But it must be a much larger galaxy.

Within the main group is the lone highly distorted spiral. It isn't red
at all. In fact it has a rather large blue tidal area between the two
larger elliptical's halos. The blue area is faint but seems real. Thus
it must be interacting with the others and its redshift a poor indicator
of distance.

The only other galaxy with a red shift in the image is 2MASX
J16471357+5333403 in the upper right corner. It fits right in with the
others with a red shift distance of 380 million light-years.

Going NW of Arp 330 about 7 minutes you come to the center of the Zwicky
galaxy cluster ZwCl 1647.6+5337 NED shows it as having 157 members in a
diameter of nearly 2 degrees, far larger than my image. It shows a red
shift distance of -- you guessed it -- 400 million light-years. It
appears nearly all its members are very red.

I've identified many of the galaxies around Arp 130 on a separate image.
You might wonder about the galaxy at the top near a bright star. It
wasn't in NED or SIMBAD. The Sky identifies it as PGC 281743 at
magnitude 16.5. Apparently it is not a IR galaxy so was missed by the 2
micron survey that picked up most of the galaxies in the image. What
about the SHK galaxies? SHK stands for Shakhbazian Compact Groups.
Number 16 on the list includes Arp 330 and surrounding galaxies. Most
of the 2MASX galaxies are also members of the SHK 16 group. Those that
are members of SHK 16 but not 2MASX cataloged galaxies I identified by
their SHK 16 number. Arp 330 carries several other group designations
such as CGPG 1648.0+5331 and I Zw 167. Like the SHK group these may
contain more galaxies than Arp did, I didn't check this however.

Arp's image of Arp 330 is at:
http://nedwww.ipac.caltech.edu/level...ig_arp330.jpeg

Even with the problems of the aurora my image goes deeper than his which
surprised me.

Rick