Neutrinos are also useful for probing astrophysical sources beyond our solar system because they are the only known particles that are not significantly attenuated by their travel through the interstellar medium.

FOS was designed to make spectroscopic observations of astrophysical sources from the near ultraviolet to the near infrared.

The satellite is a space-based X-ray telescope that will use a Wolter telescope to focus high energy X-rays at 5 to 80 keV from astrophysical sources, especially for nuclear spectroscopy.

The search will be conducted over the range of radio frequencies between 1,000 megahertz and 10,000 megahertz, the microwave region of the spectrum where there is the least background noise from astrophysical sources.

Energy in the gamma radiation range, often explicitly called gamma-radiation when it comes from astrophysical sources, is also produced by sub-atomic particle and particle-photon interactions.

The second phase consists of the remainder of the mission and was devoted to pointed observations of selected astrophysical sources.

The emission of gravitational waves from a large number of unresolved astrophysical sources can create a stochastic background of gravitational waves.

HUT was used to observe a wide range of astrophysical sources, including supernova remnants, active galactic nuclei, cataclysmic variable stars, as well as various planets in our Solar System.

However, there is a large background of muons created not by neutrinos from astrophysical sources but by cosmic rays impacting the atmosphere above the detector.

It has been observed in distant astrophysical sources, but these are poorly controlled and it is uncertain how they constrain general relativity.