#1  
Old 02-09-2011, 12:39 AM
madbadgalaxyman's Avatar
madbadgalaxyman (Robert)
Registered User

madbadgalaxyman is offline
 
Join Date: Mar 2011
Location: Brisbane
Posts: 936
More Galaxy Groups for Southern imagers

This post is additional to the previous post "Galaxy Groups for Southern Imagers.

IC 4765 cluster
Also known as Abell S805 and LGG 422

This distant, compact, dense, rich, group of galaxies was discussed in detail in the post "AGCS 805 observed" in the "Observation Reports" forum
The member galaxies themselves are mostly small, but they are very numerous, making it a worthwile target for that "galaxies as grains of sand" effect.
Furthermore, this field becomes even more impressive if you are able to image a field of 1.5 degrees diameter, or preferably 2 degrees diameter; the galaxy density is remarkably high in this part of the supergalactic structure that stretches across Pavo and adjacent constellations, so a two degree field encompasses not just the main cluster but also several other distant galaxy groups! This is a very interesting field from the astrophysical point of view, in that you get the sense that the various galaxy groups in the field may still be assembling themselves into a larger cluster.


The NGC 1332 group
This small galaxy group is compact and very well separated from the surrounding field, and it is noted for the large contrast in Hubble type between its two most prominent members.
These two major Group members are of good angular size, with both of them being about four arcminutes across;
NGC 1332 is a large and bright S0 galaxy with a very interesting elongated outline, and NGC 1325 is a prominent spiral galaxy.
In my opinion this is a fine field, because these two bright and contrasting galaxies are joined by two or three faint and interesting spirals.


The NGC 1407 group
This group is dominated by the bright elliptical galaxies NGC 1407 and NGC 1400.
While the rest of the galaxies in this group are much fainter and smaller than these two big galaxies, the attraction of this group for imagers is that these smaller galaxies are very numerous; indeed, this group is so rich that it might be thought of as a bona fide galaxy cluster.
In fact, one of the most remarkable features of this group is that it has only two very luminous members, gigantic numbers of low luminosity galaxies, but few galaxies of intermediate luminosity.
While the NGC 1407 group does not look too impressive in our electronic star charts, it could look interesting in amateur images because of its large population of very faint galaxies that are not usually plotted in our charts: for example, Trentham et al. (2006, MNRAS, 369, 1375) found that there were some 110 group members to a limit of R = 19 magnitude.

cheers,
bad galaxy man

One more group added, when I edited this entry:


The NGC 1052 group (also known as LGG 71)
(also called the NGC 1084 group)

This prominent, very obvious, and relatively compact aggregation of galaxies is less familiar to me, as it is in the south equatorial zone. Several of the galaxies are big enough to show substantial detail in amateur images.
In particular, a fine 2 degree diameter field encompasses the following nine NGC galaxies :
Group Members :
NGC 1042 , NGC 1052 , NGC 1035 , NGC 1047
Galaxies in the Background (much higher redshift) :
NGC 1064 , NGC 1033, NGC 1071, NGC 1069, NGC 1082

Better still, three of these galaxies are quite large in angular terms; occupying the diameter range 2-5 arcminutes.
Note: NGC 988 , NGC 1110 , NGC 961 , NGC 1022 , NGC 1084, and several others, all may either be outlying members of this group or galaxies associated with this galaxy group.

___________________________________ _____________
P.S.
"Just for fun and profit", I include a sky plot of some identified groups and clusters within the Fornax-Eridanus complex of galaxies. Note how some of the groups of galaxies are themselves grouped; this overdensity of galaxies near the Fornax-Eridanus border, sometimes called the Eridanus Cloud, may actually be a Supergroup.....in other words, a gravitationally bound group of Galaxy Groups!

Click image for larger version

Name:	Grps in eridanus complex.jpg
Views:	22
Size:	68.6 KB
ID:	99978

___________________________________ _______________

Last edited by madbadgalaxyman; 02-09-2011 at 10:51 PM. Reason: another galaxy group added
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 04:54 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Testar
Advertisement