UGC10923 - an interacting galaxy pair (lowenthalm)

UGC10923 - an interacting galaxy pair

This interesting interacting galaxy pair (as is usual) has multiple designations in different catalogs: UGC10923a/b, Markarian 1116, PGC 60075(big gal) and PGC 60093 (small gal), etc, etc.

The galaxy pair has a redshift of z=0.02643, which translates to a distance of about 364 million light years. The galaxies are both 43 arc seconds wide in their longest dimensions, making them each about 75,000 light years across. The small knot extending out from the end of the arm at the upper left edge of the larger galaxy (UGC10923a) may be an unrelated distant background edge on spiral. PanSTARRS imagery seems to confirm this interpretation.

Back in 2009, supernova SN 2009ij occurred in the center of the wide double arm of UGC10923a. There appear to be a chain bluish knots at this location, probably several bright star clusters rich in hot O-B stars. This would be the sort of place for a type II core-collapse supernova would commonly occur and the Asiago Supernova Catalogue does indeed list this event as being that of a type IIp supernova.

The field is rich in background galaxies, including a cluster of galaxies surrounding the giant elliptical MCG+14-08-026 (PGC 60158\) in the upper right corner of the image. This elliptical is more than 3 times farther away at 1.26 billion light years, yet appears here to be at least double the angular size of UGC10923a. This would put its size at around 600,000 light years across!

I was surprised how much showed though the bright moonlit sky. The transparency that night must have been quite good, as was certainly the seeing. I chose a target as far from the Moon as possible too, which turned out to be quite close to the north celestial pole.

Each of the 10 subs stacked for this image were themselves a stack of 320 x 1.5 second exposures live-stacked in Sharpcap.

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Status	Advanced success
Started	...
Astrometry.net job	4841354
PixInsight job	71CGCGDR939GWY832ERZAW02S0A6YVHT
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	17h19m42s.949
RA (top/left)	17h19m53s.425
RA (top/right)	17h31m27s.498
RA (bottom/right)	17h19m31s.400
RA (bottom/left)	17h08m25s.300

Dec (center)	+86°44′16″.72
Dec (top/left)	+86°33′44″.86
Dec (top/right)	+86°47′47″.68
Dec (bottom/right)	+86°54′48″.57
Dec (bottom/left)	+86°40′16″.13

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