Speaker
Description
A broadband study of $z>3$ blazars enables us to understand the evolution of the properties of relativistic jets over cosmic time. It has been found in many studies that such high $z$ blazars host $>$billion solar mass black holes and thus shed a new light on the supermassive black hole formation in the early Universe. Here, we report the first gamma-ray detection of blazars beyond $z=3.1$ using the sensitive Pass 8 dataset of Fermi-LAT. These objects are found to host extremely massive black holes at their centers, confirmed both from optical spectroscopy and accretion disk modeling. Further details of the results, including multi-wavelength follow up studies from NuSTAR and XMM-Newton, will be presented within the framework of the disk-jet connection in powerful jetted AGNs. We will also summarize the prospects of hunting these cosmic monsters with the All-Sky Medium Energy Gamma-ray Observatory (AMEGO), a probe concept study for the next NASA decadal survey. In the 200 keV to 10 GeV band, AMEGO will detect these objects by the hundreds and will provide crucial insight about the emission mechanisms powering the relativistic jets of the most powerful blazars in the Universe.
