Discovering the Mystery of Integrated Flux Nebulae

Integrated Flux Nebulae (IFNs) are a fascinating and recently recognized cosmic phenomenon. Unlike the well-known gaseous nebulae nestled within our Milky Way galaxy, IFNs reside far beyond its main body.

The Birth of Integrated Flux Nebulae

The term “Integrated Flux Nebula” was coined by astrophysicist Steve Mandel. He defined these celestial bodies as high-latitude nebulae that aren’t illuminated by a single star, but rather by the collective energy emitted by all the stars in our Milky Way galaxy. Due to their faintness, these nebula clouds require hours of exposure for capture. Composed of dust particles, hydrogen, carbon monoxide, and other elements, they form an essential component of the interstellar medium. They are particularly prominent near the north and south celestial poles. The vast nebula near the south celestial pole is known as MW9, or the South Celestial Serpent.

Early Observations and Discoveries

IFNs first appeared on photographic plates from the Palomar Sky Survey, with 30 of the 600 plates taken featuring such nebulae. These were catalogued by B.T. Lynds and later described by Allan Sandage. While studying these nebulae, astronomers like Sandage noticed peculiar dust characteristics but were unaware of the Extended Red Emission generated by some dust particles.

Mapping the Cosmic Dust

In the 1990s, two far-infrared satellites named IRAS and DIRBE were used to create a comprehensive all-sky dust map, which helped reveal the true extent of cosmic dust.

Unearthing New Horizons

During an observation session in December 2004, Steve Mandel stumbled upon a large nebula complex encircling both M81 and M82 galaxies. After consulting with radio and optical astronomers, he confirmed the discovery of a vast, relatively unknown dust complex. This revelation led to the creation of the “Unexplored Nebula Project,” where Mandel catalogued Integrated Flux Nebulae. Today, there are nine total catalogued Mandel-Wilson objects.