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Old 28-08-2011, 09:33 PM
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madbadgalaxyman (Robert)
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Galaxy Groups for Southern imagers

In response to Greg Bradley's recent question (in his recent post about the Grus Quartet), regarding the identity of southern galaxy groups that are worth imaging, I submit the following list.

I have emphasized groups of galaxies which contain at least three bright member galaxies that are of sufficient angular size to show some detail in amateur imaging. The brightest galaxies in these groups are for the most part in the range B = 12-13 magnitude.

IC 1459 group – I described this bright and prominent group of galaxies in Greg Bradley's recent post about the Grus Quartet.


NGC 3256 group
This distant group in Vela has several galaxies that are surprisingly bright for their distance.
It is noted for containing several peculiar galaxies.
Some members of the NGC 3256 group:
NGC 3256 – A very peculiar galaxy with two apparent nuclei. This galaxy is the product of the merger of two galaxies. Small angular diameter, but the surface brightness is high.
NGC 3263 /NGC 3262 interacting pair. This pair is very rarely imaged. Hardly studied in the literature!
NGC 3256C
NGC 3256B
NGC 3261 – a fine large spiral of B=12 magnitude. Rarely photographed.


Antlia Cluster of Galaxies
One of the best distant galaxy clusters for amateur imaging as it is noticeably rich, yet the galaxies are of decent angular size.
There are two concentrations of galaxies (subclusters), one around NGC 3258 and one around NGC 3268.
The S0 galaxies in this cluster, far from being “featureless” (the typical prejudice that amateurs have about S0 galaxies), actually show obvious smooth spiral structure.
This cluster also contains an interesting and very numerous population of faint blue galaxies.
The Antlia Cluster is sometimes called the Antlia Group.


NGC 6769/6770/6771 triplet and surrounding galaxy group
This is an interesting and rather rich group with at least 9 prominent members. The faint galaxy population in this cluster is very little known. These galaxies are distant, in the Pavo-Indus-Telescopium supercluster, and the galaxies are very prominent at least when we consider their considerable distance.
Some group members: IC 4836 ; IC 4845 ; IC 4827 : IC 4842 ; NGC 6782 ; IC 4852
(a nice concentration of fairly bright Non-NGC galaxies!)


NGC 6868 group in Telescopium
A scattered galaxy group dominated by very luminous Elliptical and S0 galaxies. It has had virtually no study in the professional literature of astronomy!
Some members: NGC 6868 ; NGC 6861 ; NGC 6870 ; NGC 6851 ; and many small galaxies ;


NGC 7232 / NGC 7232B / NGC7233 / IC 5181 / IC 5171
An excellent galaxy group in Grus which is very little known and studied.
Its brightest galaxies are Blue magnitude 12.5 to 13


The Dorado Group
The core of this rich group of bright galaxies is dominated by Elliptical and S0 galaxies, but the angular diameter of these galaxies should be large enough that good amateur images should show each one as an individual. Try some processing to bring out faint and low contrast detail in the S0 galaxies; there is often considerable detail to be seen in S0 galaxies, despite the “bad” reputation of these galaxies amongst amateurs.
NGC 1566 is often listed as a member of this galaxy group, but I have some evidence that this big spiral is part of a different group or subgroup at a slightly different recession velocity.
Some members of the Dorado Group: NGC 1553 ; NGC 1549 ; NGC 1546 ; NGC 1536 ; NGC 1533 ; IC 2058 ; NGC 1574
The total population of this galaxy group is remarkably large, when it is imaged to faint levels, as was found in the pioneering survey by Alan Sandage.


NGC 1395 group
This concentration of galaxies is associated with the elliptical galaxy NGC 1395.
The galaxies in this group are numerous, with ten NGC galaxies concentrated in a field some 2 degrees across. This is a well defined overdensity of galaxies that is well separated from the general field distribution of galaxies at about the same recession velocity.


Cheers,
madbadgalaxyman
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Old 29-08-2011, 08:07 AM
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gregbradley
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A fantastic list- thanks a lot for the work you put into that.

I imaged ic1459 last night. It was well positioned to image
(I think I got about 6 hours worth).

It is also quite photogenic with a couple of nice spirals in there.

I checked out another grouping the night before that Steve Crouch posted. Around NGC6872. It has an unusual S shaped galaxy as the prominent feature. I intend to continue imaging that one.

This is very helpful.

Greg.
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Old 29-08-2011, 08:58 AM
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madbadgalaxyman (Robert)
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Greg,

Thanks for your imaging efforts on southern galaxies; we really need them......amazingly, the southern sky is so poorly known and imaged that amateur images of many fairly bright galaxies will turn out to be the best images ever made of these objects.

Yeah, the IC 1459 group deserves to be better known than it is, though admittedly the member galaxies are quite small.
Overall, it is a pretty scene; with plenty of unusual galaxies thrown in to add scientific interest.

IC 1459 is nominally an elliptical galaxy, but I found on Mike Sidonio's image of this galaxy group that this galaxy has a "core + halo" structure indicative that there may be a more extended disk(possibly planar) component which extends outside of the spheroidal ("elliptical") component of this galaxy.
This would make it an S0 galaxy rather than an elliptical.

cheers,
Robert

N7418A is a faint and unusual object; the regions outside of its bulge are very L.S.B. even on DSS images....so it would be tough to bring out the structure of this object in an image.
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