Object of the Week, 3 April 2022 - An obscure alignment in UMa
Spring is here. Galaxies galore. For this week's OOTW I decided to go with an obscure group in Ursa Major. Some aperture required.
UGC7064A lives in the north-northeastern regions of the Great Bear. Brightest galaxy in the vicinity is NGC3945, 1.4 degrees to the east.
But if it carries the designation UGC7064A, there sure must be a UGC7064 without the A..? There is, but it's 29 degrees to the south-southwest, also in Ursa Major and better known as the group Holmberg 232 / Rose 8 / KTG 41.
Here is our object of the week, @ 12:04:44 +60d40m20s. Both images are only 5 minutes of arc in size:
In NED it is listed as a galaxy triple with a population count of 4 (...). It's a bit of a confusing mess when it comes to designations. Let's break it down.
Starting in the west, we see a bright little fellow. NED designates it UGC7064A NED01. But it's a star, as confirmed by SDSS, known as 4UCAC754-046749 (a.k.a. SDSS J120441.17+604019.3).
West of center is the brightest galaxy of the bunch: PGC38217, UGC7064A NED02. SIMBAD says this is both UGC7064A & B, where NED does not list anything other than -A, but only for the group as a whole. Its nucleus is a tad fainter than the star to its west appears to be.
To the east of PGC38217 is PGC200281, UGC7064A NED03. Like its sibling to the west it is very small and faint, but it does sport a prominent dark lane along with a nucleus. SIMBAD says it's UGC7064C.
I think it's clear to conclude that the two PGC galaxies are interacting. The long east-northeast to west-southwest extending lane, that appears to be passing through both galaxies, is evident.
The easternmost galaxy is SDSS J120448.91+604019.6. It too reveals a nucleus. Its redshift indicates it is in the distant background and not a physical member of this group.
There's little to none information about this group on the web. This image on Flickr is a beauty, though: https://www.flickr.com/photos/geckzilla/48267298226
As the image reveals, SDSS J120441.17+604019.3 is indeed as star. To its west, on the western edge of the extending lane, is yet another faint galaxy. It may be SDSS J120439.72+604016.1, although classified as a star in SDSS.
As always, I have pieced together an observing guide for this OOTW. Click here to download it.