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Old September 29th 10, 06:04 PM posted to alt.binaries.pictures.astro
Glen Youman
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Posts: 177
Default ASTRO: NGC 210 An Arp-like galaxy


An impressive galaxy - Cetus is in the Sacramento light dome where the
LP gradients are horrendous but still worth a try. Good job.

On Tue, 28 Sep 2010 00:38:37 -0500, Rick Johnson
wrote:

NGC 210 sure belongs on Arp's list though somehow he missed it. Could
be the detail just wasn't visible to film of his time but the dust lanes
were known in 1961 but without the internet he might have not found that
paper. I had to really process the heck out of it to show the features
near the core. Namely the odd dust lane(s) that cuts across everything
and the ring of star clouds around the core. I see the dust lane on a
couple internet images but didn't suspect the star clouds that popped
out when I processed for the dust lane. I believe they are real as I
can see them if I do a histogram stretch of the region with just the
right values using the raw FITS file stack. The high pass filter though
brought them out much better in the processed image. Most papers refer
to there being two dust lanes. At first I thought I saw two, a short
one coming from the north to the core and a much longer one coming in
from the south but after processing they merged into one. If so it/they
may be a foreground feature and not part of the galaxy at all. Unlikely
but possible

NGC 210 is also odd in that it has a bright inner core (greatly reduced
in intensity in my image to preserve detail) that is a tight spiral disk
with small nucleus. Outside this are two wide spread arms in a faint
disk. There's only a faint hint of a bar connecting them to the inner
bright region. Sort of like a barred spiral whose bar has faded nearly
away.

I find it classed SbI one place, S(rs)b another and SAB(s)b yet another.
NGC project says SAB(s)bI. Take your pick. It lies some 60 to 70
million light years from us as best as I could determine.

A radio image if the galaxy shows it has a HI (non ionized hydrogen)
tail that extends down to and a bit past the galaxy to its southeast in
my image, PGC 169998/2MASX J00410068-1358160. This is just a
coincidence as that galaxy is some 700 million light years distant and
thus not involved. Though the tail does indicate it has interacted with
some other galaxy in the past. No it's not the one to the NE. I agree
it is really strange as well and certainly could be a candidate. It is
PGC2454/MCG -02-02-082 but it is 370 million light years from us so too
isn't a candidate. But it sure ran into something it appears.

More likely is NGC 178 out of the image to the southwest. It is still
to be imaged unfortunately. These are at -14 degrees so further south
than I can go except for rare nights. I never got another after taking
NGC 210 last fall. There are other candidates such as PGC 2465 out of
the image to the north northeast as well as some others that form a
small group with NGC 210 being the core. All have red shift values in
the 50 to 70 million light year range so likely do form a true group
that could have had all sorts of interactions in the past.

This field is not covered by the Sloan survey so few galaxies are
cataloged and most that are are just anonymous listings in the UK
automatic plate measurement survey that records only brightness and
crude spectral data. A few IR galaxies from the 2MASS survey are
included as well.

The bright galaxy seen through the outer arms of NGC 210 at 4 O'clock is
2MASX J00403079-1353088. There's no distance data.

The only other galaxy with a known red shift is southwest of 2MASX
J00410068-1358160, the one the tail of NGC 210 extends to south east of
NGC 210. Halfway between that galaxy and a bright blue star are a pair
of spindle shaped galaxies. The one on the left is 2MASX
J00404728-1400190 at 680 million light years, about the same as the much
larger 2MASX J00410068-1358160. Several other small galaxies are in the
area. Are they part of this group? I have no idea.

Adam Block's image of this galaxy,
http://www.noao.edu/outreach/aop/observers/n210.html, shows what appears
to be an extended outer halo about the galaxy. I put more luminosity
time into it, more than he did in fact, but I saw no sign of it in my stack.

14" LX200R @ f/10, L=7x10', RGB=2x10'x3, STL-11000XM, Paramount ME