NGC 3621


NGC 3621 is a disk spiral galaxy about away in the equatorial constellation of Hydra. It was discovered by German-British astronomer William Herschel on 17 February 1790.
NGC 3621 is comparatively bright and can be well seen in moderate-sized telescopes. The galaxy is around across and is inclined at an angle of 66° from being viewed face on. It shines with a luminosity equal to 13 billion times that of the Sun. The morphological classification is SAd, which indicates this is an ordinary spiral with loosely wound arms. There is no evidence for a bulge. Although it appears to be isolated, NGC 3621 belongs to the Leo spur.
This galaxy has an active nucleus that matches a Seyfert 2 optical spectrum, suggesting that a low mass supermassive black hole is present at the core. Based upon the motion of stars in the nucleus, this object may have a mass of up to three million times the mass of the Sun.

Supernova

One supernova has been observed in NGC 3621: SN 2024ggi was discovered by Asteroid Terrestrial-impact [Last Alert System|ATLAS] on 11 April 2024. By 16 April it had brightened to magnitude 12, and got as bright as magnitude 11.9, making it the brightest supernova of 2024. It was the closest supernova to Earth since SN 2023ixf, which had been discovered on 19 May 2023. A search of archival Hubble Space Telescope and Spitzer Space Telescope images showed the suspected progenitor star, identified as a red supergiant. The mass of the progenitor has been estimated at 12-15.