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[APML] Some info on Abell 2151
Here's a little write up I did on the Hercules cluster A2151 plus a recent
image collaboration by
Jim Misti and myself
http://www.robgendlerastropics.com/HerculesJM.html
Hercules Galaxy Cluster (Abell 2151)
Distance: 500 Million Light Years
The Hercules cluster, Abell 2151 is the dominant galaxy of the Hercules
supercluster which contains 12 Abell galaxy clusters and spans some 6
degrees of sky. The Hercules supercluster was first recognized by Harlow
Shapely in the 1930's. The supercluster is split into a northern and
southern (larger) superclusters which are physically connected by a bridge
of galaxies and reside at distances of 400 and 500 million light years
respectively. Abell 2151 is the richest cluster within the supercluster in
terms of galactic members, especially large spirals which make up 50% of the
cluster. Abell 2151 is itself made of subclusters designated N, C, and E.
The bumpy distribution of intracluster gas and presence of distinct
subclusters suggest that A2151 is relatively unevolved and is still
undergoing collapse and coalescence. Current thinking is that galaxy
clusters form from large scale mergers of smaller subclusters and groups.
The mergers are responsible for changes in the physical dynamics and
structure of the clusters and intercluster medium.
The Hercules cluster (A 2151) and Hercules supercluster are part of a huge
sheetlike megastructure of galaxies known as the "Great Wall". The Great
Wall also includes the Coma and Leo clusters and extends along a filament
some 500 million light years in length terminating with the Hercules cluster
at one end. The Great Wall was the first megastructure of its kind
discovered by the American astronomers Margaret Geller and John Huchra in
the 1980's. Many more wall structures are now known to exist. Superclusters
are the largest gravitationally bound structures known in the cosmos. They
in turn are comprised of smaller galaxy clusters and groups. Superclusters
can reach enormous sizes up to several hundred million light years and are
often juxtaposed against large voids in space where few galaxies exist.
Their existence indicates that galaxies in the universe are not evenly
distributed but are arranged in large coherent structures of clusters,
superclusters, walls and filaments. Astronomers estimate that approximately
10 million superclusters may exist in the observable universe.
An extensive catalogue of galaxy clusters was compiled by the American
astronomer George O. Abell (1927-1983). He published his original catalogue
in 1958 which was later completed posthumously in 1987 and includes
approximately 4000 clusters out to a redshift of Z=0.2.
Rob Gendler
email: robgendler@att.net
Web Site: http://www.robgendlerastropics.com
----- Original Message -----
From: "Rodney Watters" <ryderhome@bigpond.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Sunday, June 05, 2005 7:51 PM
Subject: Re: [APML] Coordinates for Abell 2151?
> Alan,
>
> According to Urano Metria 2000.0 Deep Sky field guide, A2151 is described
> as:
>
> "Hercules Galaxy Cluster. Somewhat strong concentration at center; many GX
> spread over whole area of cluster."
>
> Following information is included:
> RA: 16 05 12.0
> DEC: +17 44 00
> Mag. 13.8
> No. Gal: 87
> Diam: 56'
>
> Rodney
>
>
>
> ----- Original Message -----
> From: "Alan Voetsch" <alanv12952@yahoo.com>
> To: "APML" <astro-photo@seds.org>
> Sent: Monday, June 06, 2005 9:32 AM
> Subject: [APML] Coordinates for Abell 2151?
>
>
> > All,
> >
> > Can someone let me know what the location (RA and Dec) is for the
> > center of this galaxy cluster in Hercules? I cannot seem to find it in
> > my meager atlas. I think I'd like to try a long exposure of this area
> > to see what turns up.
> >
> > Thanks,
> > Alan
> >
> > SCT Astrophotography: http://www.pbase.com/avoetsch/astrophotography
> > FS-102 G-11/Gemini: http://www.pbase.com/avoetsch12952/tak_fs102
> > & http://www.pbase.com/avoetsch12952/fs102
> > & http://www.pbase.com/avoetsch12952/takpf
> >
> >
> >
> > __________________________________
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