NGC 3447

NGC 3447 is a barred Magellanic spiral galaxy located in the constellation Leo. Its speed relative to the cosmic microwave background is 1,405 ± 34 km/s, which corresponds to a Hubble distance of 20.7 ± 1.5 Mpc (∼67.5 million ly). It was discovered by the British astronomer John Herschel in 1836.

NGC 3447 shows a broad HI line.

With a surface brightness equal to 15.61 mag/am^2, NGC 3443 is classified low surface brightness galaxy (LSB). LSB galaxies are diffuse galaxies with a surface brightness less than one magnitude lower than that of the ambient night sky.

To date, four non-redshift measurements yield a distance of 13.730 ± 9.802 Mpc (∼44.8 million ly), which is slightly outside the range values of Hubble.

NGC 3447A
NGC 3447A, also known as UGC 6007, is an irregular galaxy in contact with NGC 3447. It has roughly the same apparent magnitude, and has a slightly lower surface brightness. Due to gravitational forces, it has become distorted, showing disrupted spiral arms and remnants of its spiral structure, hinting it might be a spiral galaxy in the past.

Supernovae
The supernova SN 2012ht was discovered in NGC 3447 by Koichi Nishiyama and Fujio Kabashima on December 18, 2012. This supernova was of type Ia.

NGC 3447 group
NGC 3447 is the largest galaxy in a group of galaxies named after it. The NGC 3447 group includes at least 4 other galaxies: NGC 3447A, NGC 3457, UGC 6022 and UGC 6035.