The Galactic Connection : Keenan's System (Bogdan Borz)

The Galactic Connection : Keenan's System

This is the Keenan system, a system of interacting galaxies in the Ursa Major constellation located at around 17.3 million light years from earth. The two galaxies are connected by a bridge that seems to be formed by material and stars captured from the outskirts of NGC218 (Gallagher and Parker, The Astrophysical Journal 2010). NGC5218 is a barred spiral galaxy, while NGC 5216 is an elliptical galaxy. The length of the bridge is 38 kiloparsecs.

“First discovered by Friedrich Wilhelm Herschel in 1790 and later studied as Intergalactic Nebulae in 1926 by Edwin Hubble, it wasn’t until 1935 until PC Keenan noted this double galaxy mystery seemed to be connected by “luminous debris” – a connection that spans 22,000 light years. Keenan noted the peculiar structure in his paper but it would be 1958 before the bridge of material was “rediscovered” by observers at Lick and Palomar observatories in “The Interaction of Galaxies and the Nature of Their Arms, Spanning Filaments and Tails”. (Tammy Plotner, Universe Today, 2008).

I was pleased to see that my image after photometric color calibration produced colors coherent with what is described in the scientific literature, NGC 5216 being situated on the red sequence and having a blue color only on the outer shells, which seems to be an intrinsic characteristic, not due to the contamination by the bridge. The only star formation region in NGC 5216 is the blue southwestern tidal tail that is very narrow. However, there is a very faint end the spurs the tail visible on the image that continues to the southwestern region slightly above the background value. Probably a very long exposure could make it more evident.

The image is a close-up, given the focal length of my telescope. I added a wider field in the second version.

Final
Original
B

B

Title: Widefield

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Status	Advanced success
Started	...
Astrometry.net job	8328837
PixInsight job	Y7WC8A25KJ3X99AMOCXXVMKXZCWYKPWY
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	13h32m01s.709
RA (top/left)	13h33m53s.833
RA (top/right)	13h33m01s.920
RA (bottom/right)	13h30m07s.941
RA (bottom/left)	13h31m02s.535

Dec (center)	+62°42′16″.87
Dec (top/left)	+62°29′56″.43
Dec (top/right)	+62°58′45″.92
Dec (bottom/right)	+62°54′32″.10
Dec (bottom/left)	+62°25′45″.35

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