Interacting galaxy with NGC 7731
RA 23 41 33.852
Dec +03 43 29.83
Magnitude 14.25
Angular Size (arc minutes) 1.98 x 0.7

ZwickysPiercedGalaxy.JPG

NGC 7732 is directly south of the bright star in the image, with NGC 7731 immediately to the west of the star.

The only place I’ve seen this galaxy referred to as Zwicky’s Pierced Galaxy is in Interstellarum. It certainly got my attention and I couldn’t help imagining what unusual shape and/or astrophysical reason inspired this awesome name - so I observed it as soon as I could. Here’s my observation from the 2016 Oregon Star Party:

“So last night I found IC 1504 and thought it was Zwicky’s Pierced Galaxy (GREAT name and I’ve got to look it up when I get home). But this is the real deal, NGC 7731 and 7732. I looked up the DSS image of this pair in Megastar and it wasn’t obvious why it has such an evocative name, and visually it’s a low surface brightness elongated galaxy with an off-center area that’s brighter than the rest of the galaxy. I’m intrigued to learn more about how this seemingly run of the mill galaxy got its name. 476x, 21.68 SQM.”

NGC7731_28inch.JPG NGC7731_28inch_invert.jpg

And through Jimi’s 48 inch in October 2016:

“Alright, now this really looks like a galaxy that should have a name. It has a mottled, granular look to its central axis and the brightest, widest end shoots off to the left of the FOV. It’s all low surface brightness though. 700x, 21.35 SQM”.

NGC7731_48inch.JPG NGC7731_48inch_invert.jpg

To my surprise it looked rather ordinary in my 28-inch scope, but it does have considerable interest because it’s interacting with nearby NGC 7731. In Jimi’s scope it looked somewhat like a fat check mark. Photos show the hook area looking like an area active star formation area that’s possibly been perturbed by NGC 7731.

My guess is that the name comes from the “V” shape of the star forming area and its visual suggestion of piercing the side of the galaxy. But so far I haven't found any online references to Zwicky’s Pierced Galaxy - does anyone know where the name came from?

Regardless, these two galaxies make an attractive pair and the view is made even more lovely with a handful of field stars.

"GIVE IT A GO AND LET US KNOW"