| NGC 561 | |
| Epoch: | J2000 |
| Constellation Name: | Andromeda |
| Appmag B: | 14.1 |
| Sbrightness: | 23.44 mag/arcsec2 |
| Z: | 0.015758 |
| H Radial V: | 4687 ± 4 km/s |
NGC 561 is a barred spiral galaxy located in the constellation Andromeda.[1] Its speed relative to the cosmic microwave background is 4,395 ± 20 km/s, which corresponds to a Hubble distance of 64.8 ± 4.6 Mpc (~211 million ly).[2] NGC 561 was discovered by Prussian astronomer Heinrich d'Arrest in 1862.[3]
The luminosity class of NGC 561 is I and it has a broad HI1 line.[4]
NGC 561 is part of the NGC 507 group. This vast group includes at least 42 galaxies, 21 of which appear in the NGC catalog and 5 in the IC catalog. Four members of this group are also Markarian galaxies. The brightest of these galaxies is NGC 507 and the largest is NGC 536.