This Image captures the wonderful galaxy cluster Abell 2151, located 500 million light years away in the constellation of Hercules at a declination of +18 degrees.  The cluster consists of about 200 galaxies and is one of the few galaxy clusters without a huge elliptical galaxy at its center, at least not yet.

As many of you know, galaxy pairs which we today view as merging were viewed by Dr. Arp as splitting apart.  This was consistent with another of his beliefs -  that galaxies are ejecting material.  In the 1972 paper by Dr. Arp entitled, “Ejection of Small Compact Galaxies from Larger Galaxies”, Dr. Arp displayed some new images he had taken which show that galaxies eject luminous matter.  The first figure in the paper is a photograph of 3 hours duration of galaxy IC 1182.  IC 1182 is the object seen at the far left edge of my image. His image was taken using the 200 inch Hale telescope, the largest telescope in the world at that time.  A comparison of my image to his is shown in my mouseover view.

This is how Dr. Arp describes his image – “The object, IC 1182, shows a long straight jet with compact, high surface-brightness objects along its length. More diffuse luminous material extends generally in the direction opposite to the jet.”  To be clear, although Dr. Arp studied this unusual object, he did not include it in his Arp catalog.

It does look like a jet is being emitted from the left side of the galaxy.  But recent work in the 2019 paper, ‘The peculiar galaxy IC 1182: An ongoing merger?”, shows that this is not a jet.  Instead, it is a thin tail, the result of a past merger.  A broader tail is on the opposite side of the galaxy, extending upwards.  Revision D compares this object with Arp 226 , which is clearly a merger. Similarities can be seen in the streams of both objects.

Although I don’t agree with Dr. Arp on his interpretation of this object as a galaxy emitting luminous material in the form of a jet, I still have the utmost respect for the bulk of Dr. Arp's work.  His efforts on peculiar galaxies was groundbreaking and contributed so many great ideas and observations which have shaped our views of these lovely objects.