NGC 4258 (M106) - barred spiral galaxy in the constellation Canes Venatici

Annotated B/W image

Most popular cross-identifications for the galaxy NGC 4258: M 106, UGC 7353, PGC 39600, Messier 106

Coordinates:

RA (2000): 12h 18m 57.54s
Dec (2000): +47° 18′14.3″

NGC 4258 (M106) is a barred spiral galaxy contains an active nucleus classified as a Type 2 Seyfert. Several studies investigate the distance to it. Humphreys et al. (2013) measure the distance as 7.2 Mpc but the latest results reveal that the distance to NGC 4258 is 7.576 Mpc. NGC 4258 is a critical galaxy for establishing the extragalactic distance scale and estimating the Hubble constant (H0). The value of H0 is in excellent agreement with that derived using Cepheids calibrated by the distance to NGC 4258 of H0 = 72.0 km s-1 Mpc-1 (Reid et al., 2019).

The nucleus of NGC 4258 hosts a H2O megamaser in a sub-parsec-scale accretion disk surrounding a very massive black hole (Reid et al., 2019). The galaxy has a peak rotation speed of 208 km/s (Erickson et al. 1999), slightly less than that of the Milky Way (MW).

NGC 4258 is the dominant galaxy of the Canes Venatici (CVn) II group. Several dwarf companions are already known. Erickson et al. (1999) confirmed NGC 4248 as a bright companion via an HI redshift and Jerjen et al. (2001) confirmed UGC 7356. The results of an extensive search for dwarf satellite galaxies around host galaxies in the Local Volume up to distance of 12 Mpc reveals 33 candidates around NGC 4258 / M106. (Carlsten et al., 2020).

Charts and image details obtained from Astrometry.net

Image and FOV details

RC 12" Astrograph (IRIDA South dome)

Imaging details

ASA 12" Astrograph (IRIDA North dome)

Imaging details