University of Maryland, College Park | 2018 Oct 03
Space jets accelerate particles and send a high-energy signal to Earth
The night sky seems serene, but telescopes tell us that the universe is filled with collisions and explosions. Distant, violent events signal their presence by spewing light and particles in all directions. When these messengers reach Earth, scientists can use them to map out the action-packed sky, helping to better understand the volatile processes happening deep within space.
For the first time, an international collaboration of scientists has detected highly energetic light coming from the outermost regions of an unusual star system within our own galaxy. The source is a microquasar—a black hole that gobbles up stuff from a nearby companion star and blasts out two powerful jets of material. The team’s observations, described in the October 4, 2018 issue of the journal Nature, strongly suggest that electron acceleration and collisions at the ends of the microquasar’s jets produced the powerful gamma rays. Scientists think that studying messengers from this microquasar may offer a glimpse into more extreme events happening at the centers of distant galaxies.
The team gathered data from the High-Altitude Water Cherenkov Gamma-Ray Observatory (HAWC), which is a detector designed to look at gamma-ray emission coming from astronomical objects such as supernova remnants, quasars and rotating dense stars called pulsars. Now, the team has studied one of the most well-known microquasars, named SS 433, which is about 15,000 light years away from Earth. Scientists have seen about a dozen microquasars in our galaxy and only a couple of them appear to emit high-energy gamma rays. With SS 433’s close proximity and orientation, scientists have a rare opportunity to observe extraordinary astrophysics.
“SS 433 is right in our neighborhood and so, using HAWC’s unique wide field of view, we were able to resolve both microquasar particle acceleration sites,” said Jordan Goodman, a Distinguished University Professor of Physics at the University of Maryland and U.S. lead investigator and spokesperson for the HAWC collaboration. “By combining our observations with multi-wavelength and multi-messenger data from other telescopes, we can improve our understanding of particle acceleration in SS 433 and its giant, extragalactic cousins, called quasars.” ...
Very High Energy Particle Acceleration Powered by the Jets of the Microquasar SS 433 ~ A.U. Abeysekara et al
- Nature 562(7725):82 (04 Oct 2018) DOI: 10.1038/s41586-018-0565-5