NGC 3913

Background

NGC 3913 was discovered by German‑British astronomer William Herschel on 14 April 1785. It was later observed by Lewis Swift on 8 May 1890, leading to its additional listing in the Index Catalogue as IC 740. The SIMBAD database lists NGC 3913 as an Active Galaxy Nucleus Candidate, meaning it hosts a compact central region that emits significant energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by stars.

The galaxy's distance is uncertain: its velocity with respect to the cosmic microwave background corresponds to a Hubble distance of 16.58 ± 1.17 Mpc, while three non‑redshift measurements give a much closer distance of 8.297 ± 4.352 Mpc. NGC 3913 is part of the NGC 3631 group (LGG 241), which includes at least ten galaxies such as NGC 3631, NGC 3657, NGC 3718, NGC 3729, NGC 3972, NGC 3998, and UGC 6251. NGC 3631 is also a member of the M109 Group.

Three supernovae have been observed in NGC 3913: SN 1963J (Type Ia, magnitude 13.7) discovered by Fritz Zwicky and Paul Wild on 18 May 1963; SN 1979B (Type Ia, magnitude 16) discovered by Leonida Rosino on 28 February 1979; and SN 2026dix (Type IIb, magnitude 16.2) discovered by the MASTER program on 16 February 2026.