Arp 117 (with Arp 79) (Gary Imm)

Arp 117 (with Arp 79)

This image captures 2 Arp objects located 270 million light years away in the constellation of Bootes at a declination of +18 degrees.

Arp 79, also known as PGC 50584, is the small barred grand spiral galaxy at the bottom of the image. It spans 1 arc-minute in our apparent view, which corresponds to an actual diameter of 70,000 light years. Two strong arms are visible in this galaxy. The left arm contains two large star cluster knots. The right arm has a bright area which, because of its yellow color, looks more like a foreground star than a knot. This galaxy was classified by Arp into the category of “Spiral Galaxies with Large High Surface Brightness Companions”, but I really don’t see anything here that looks like a companion. But, the arms appear disturbed a bit, with hints of Vorontsov-Velyaminov rows, so perhaps a companion is hiding in there someplace.

Arp 117, also known as IC 983 and IC 982, is the pair of galaxies towards the top of the image. IC 983 is a beautiful huge barred spiral galaxy whose disk is fascinating in both color and structure. This galaxy may be the largest I have ever imaged, at almost 300,000 light years in diameter. IC 982 is an elliptical galaxy with a diameter of 90,000 light years. Some disturbance is seen in the lower arms of IC 983, but I am surprised at the lack of strong star streams between these 2 galaxies. I think that they are further apart than they appear to us. These galaxies were classified by Arp into the category of “Elliptical Galaxies close to and Perturbing Spiral Galaxies”.

Many other background galaxies are also visible in this image.

Final
Original
B

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Description: Comparison to Original Arp 117 Image

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Status	Advanced success
Started	...
Astrometry.net job	4193505
PixInsight job	MXG9SI4SFP8SE0SFRWJLE8DF2C4O10WP
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	14h10m03s.920
RA (top/left)	14h10m45s.540
RA (top/right)	14h09m20s.995
RA (bottom/right)	14h09m22s.381
RA (bottom/left)	14h10m46s.780

Dec (center)	+17°41′48″.87
Dec (top/left)	+17°49′50″.62
Dec (top/right)	+17°49′26″.29
Dec (bottom/right)	+17°33′46″.55
Dec (bottom/left)	+17°34′10″.92

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