NSF Award
1716507
Quasars can launch thin structures that stretch over hundreds of light years. Some of these large-scale jets are unusually bright at X-ray wavelengths. For more than a decade, a standard model seemed to explain this brightness. But the team's new observations of a few jets could not be fit by the standard model. The team developed an alternative model that did fit. In their model, particles are accelerated to extreme energies all along the jet. The team will examine many more large-scale jets. They will see if the standard model or their alternative model best fit the observations. Senior team members will train junior team members, some from underrepresented groups. The team will develop an interactive web page to convey the research to K-12 students. The web page will be submitted for curation by the American Association of Physics Teachers.<br/><br/>The team will critically examine the prevailing theory for the nature of the anomalous X-ray emission in large-scale quasar jets, namely that this emission is due to cosmic microwave background photons being inverse-Compton scattered by 30-100 MeV energy jet electrons. They will also investigate the implications of their alternative explanation, namely that the X-rays are synchrotron emission from 30-100 TeV electrons accelerated in situ. The team's prior work suggests that the resulting TeV photons could heat the intergalactic medium, thereby reducing the number of dwarf galaxies formed. The team will develop this idea further.
