NGC 7550
NGC 7550 is an lenticular galaxy located in the Pegasus constellation. Its velocity relative to the cosmic microwave background is 4,598 ± 29 km/s, which corresponds to a Hubble distance of 67.8 ± 4.8 Mpc. It was discovered by the German-British astronomer William Herschel in 1784.
Observations
NGC 7550 forms a triplet of galaxies in gravitational interaction with its neighbors NGC 7547 and NGC 7549, a triplet that appears in Halton Arp 's Atlas of peculiar galaxies under the designation Arp 99. According to Professor Seligman, NGC 7547 is not part of the Arp atlas and is confused with NGC 7549, but it is undoubtedly part of the triplet with NGC 7550, the brightest of the three galaxies. The distance to these three galaxies is approximately the same. The other two galaxies are NGC 7547 and NGC 7549. The Hubble distances of these three galaxies are approximately the same and are respectively equal to 65.0 ± 4.6 Mpc, 67.8 ± 4.8 Mpc and 64.5 ± 4.5 Mpc.NGC 7550 Group
NGC 7550 is part of a triplet of galaxies, the NGC 7550 group, the brightest of the three galaxies. The distance to these three galaxies is approximately the same. These three galaxies are NGC 7547, NGC 75 and NGC 7549, whose Hubble distances are respectively.The NGC 7550 group is also designated by the NASA/IPAC database as WBL 700, named after the authors who published an article in 1999. Unfortunately, the designations of the galaxies are not given in this article, but it is undoubtedly NGC 7553 whose Hubble distance of 70.95 ± 5.03 Mpc is comparable to that of the galaxies in the triplet. NGC 7558, a member of the Hickson 93, is a relatively distant galaxy at 124.54 ± 8.75 Mpc.