NGC 3756

Lore & Background

NGC 3756 was discovered by German-British astronomer William Herschel on 14 April 1789. Its velocity with respect to the cosmic microwave background corresponds to a Hubble distance of 21.62 ± 1.53 Mpc, while 28 non-redshift measurements give a similar mean distance of 19.454 ± 0.682 Mpc. The galaxy has a possible active galactic nucleus, meaning it hosts a compact region at its center that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by stars.

NGC 3756 is a member of the NGC 3898 group (also known as LGG 250), which contains at least nine galaxies. The other members are NGC 3733, NGC 3794, NGC 3846, NGC 3846A, NGC 3850, NGC 3898, NGC 3982, and UGC 6894. One supernova has been observed in NGC 3756: SN 1975T, discovered by Swiss astronomer Paul Wild on 28 December 1975. It reached maximum brightness at magnitude 15.7 around 11 January 1976, and although never officially classified, its light curve suggested it was a Type II supernova.

Reader's Guide

NGC 3756 holds significance as a member of the NGC 3898 group, a collection of at least nine galaxies that provides context for studying galactic interactions and evolution within a small group environment. Its possible active galactic nucleus makes it a candidate for understanding the energetic processes at the centers of galaxies, where a compact region emits energy across the electromagnetic spectrum in a manner distinct from stellar sources. The galaxy's distance measurements, derived from both Hubble flow and non-redshift methods, offer a consistent picture of its location at roughly 19 to 22 megaparsecs, aiding in calibrating cosmic distance scales. The observation of SN 1975T, a supernova with a light curve suggestive of a Type II event, adds to the galaxy's legacy as a site of stellar death and nucleosynthesis. Though the supernova's type was never officially classified, its study contributes to the broader understanding of supernova behavior. NGC 3756's discovery by William Herschel in 1789 places it within the historical catalog of deep-sky objects, linking modern astrophysical research to the early days of systematic astronomical observation.

Did You Know?

• It has a possible active galactic nucleus, emitting energy not produced by stars.
• One supernova, SN 1975T, was observed in NGC 3756 and reached magnitude 15.7.
• The galaxy is a member of the NGC 3898 group, which contains at least nine galaxies.