Physical Information: Based on a recessional velocity relative to the Cosmic Background Radiation of 12610 km/sec (and H₀ = 70 km/sec/Mpc), a straightforward calculation indicates that PGC 8029 is about 585 to 590 million light-years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 560 million light-years away at the time the light by which we see it was emitted, about 570 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light-travel time). Given that and its apparent size of about 1.05 by 0.8 arcmin (from the images below) for the main galaxy and its brighter extensions, the galaxy and its brighter extensions are about 170 thousand light-years across; with the much fainter extensions to the northwest, the overall structure spans about 1.9 arcmin, so material is scattered over a region spanning more than 300 thousand light-years.
 The brightness of Markarian 1018 has been sporadically varying (usually getting fainter but occasionally brighter) by as much as a factor of eight for years; the cause of this was shown (in late 2016) to be a variation in the amount of material falling into a supermassive black hole at its center (such infall creates the radiation that justifies its classification as a Seyfert galaxy of type Sy 1.5). The reason for the varying rate of infall is unknown, but since the galaxy is almost certainly the result of a merger between two galaxies (as shown by the distorted shape of its outer regions), it probably has two black holes near its center, and one of them may be altering the distribution of material falling into the other.

Physical Information: Based on a recessional velocity relative to the Cosmic Microwave Background radiation of 5315 km/sec (and H₀ = 70 km/sec/Mpc), PGC 8161 is about 245 to 250 million light-years away. Given that and its apparent size of about 1.4 by 1.05 arcmin (from the images below), the galaxy is about 100 thousand light-years across.
Usage By The Arp Atlas: PGC 8161 is used by the Arp Atlas of Peculiar Galaxies as an example of a spiral galaxy (PGC 8161) with a small high surface brightness companion (2MASX J02082216+4128061 = Arp 74B), with the note "Broad, diffuse extension of arm leads to companion."

Physical Information: There is almost no information available about this galaxy (though VizieR does give its visual magnitude), and although the unusual structure of its apparent companion suggests an interaction with something, most situations in which a small compact galaxy interacts with a larger spiral show some kind of actual interaction, which this system does not. So it is quite possible that Arp 74B has nothing to do with its apparent companion, and is a foreground or background galaxy; but if it is at the same distance as PGC 8161 (about 245 to 250 million light-years), then its apparent size of about 0.3 by 0.2 arcmin (from the images of PGC 8161, which see) would make it about 20 thousand light-years across. Of course if it is closer then it is smaller than that, and if it is further away it is larger.
Usage By The Arp Atlas: This galaxy is used by the Arp Atlas of Peculiar Galaxies as an example of a spiral galaxy (PGC 8161) with a small high surface brightness companion (2MASX J02082216+4128061 = Arp 74B), with the note "Broad, diffuse extension of arm leads to companion."
Classification Note: NED lists this as type IrS, presumably meaning something in between an irregular or spiral galaxy, and if of type dm or m, that seems a reasonable possibility, hence the type shown in the description line above; but since there is no indication of any structure worth mentioning, it could be just an elliptical galaxy (though it would probably be redder if it were an elliptical, which is why that possibility is not shown above).

Note About Classification: The type is taken from the Spitzer Survey of Stellar Structure in Galaxies.