Scientists have suspected that some ULXs might be hidden from view for this reason. SS 433 provided a unique chance to test this idea because, like a top, it wobbles on its axis a process astronomers call precession.

Most of the time, both of SS 433s cones point well away from Earth. But because of the way SS 433 precesses, one cone periodically tilts slightly toward Earth, so scientists can see a little bit of the X-ray light coming out of the top of the cone. In the new study, the scientists looked at how the X-rays seen by NuSTAR change as SS 433 moves. They show that if the cone continued to tilt toward Earth so that scientists could peer straight down it, they would see enough X-ray light to officially call SS 433 a ULX.

Black holes that feed at extreme rates have shaped the history of our universe. Supermassive black holes, which are millions to billions of times the mass of the Sun, can profoundly affect their host galaxy when they feed. Early in the universes history, some of these massive black holes may have fed as fast as SS 433, releasing huge amounts of radiation that reshaped local environments. Outflows (like the cones in SS 433) redistributed matter that could eventually form stars and other objects.

But because these quickly consuming behemoths reside in incredibly distant galaxies (the one at the heart of the Milky Way isnt currently eating much), they remain difficult to study. With SS 433, scientists have found a miniature example of this process, much closer to home and much easier to study, and NuSTAR has provided new insights into the activity occurring there.

Originally posted here:

Stars and Galaxies . Seeing Some Cosmic X-Ray Emitters Might Be a Matter of Perspective - Jet Propulsion Laboratory