Description:

Title: The journey of relativistic astrophysical jets

Speaker:Dimitrios Giannios, Purdue University

Abstract: 

When black holes are fed gas by their environment, they convert gravitational
energy into radiation extremely efficiently and, surprisingly, eject
plasma in the form of powerful collimated flows at a speed close to
the speed of light, producing "relativistic jets".
Relativistic jets are observed to emerge from supemassive black holes
located at galactic centers but also theorized to mark the birth of solar-mass
black holes or neutron stars powering gamma-ray bursts. When pointing
towards Earth, relativistic jets are
spectacular sources that outshine their host galaxy and show extremely
bright, broadband flares on very short timescales.
Furthermore, the compact object formation process makes for a powerful source
of gravitational waves, detectable with LIGO.

The common hypothesis for jet formation is that they are launched by
magnetic fields that thread the black hole and the surrounding
gas. I will discuss the journey of the jet from its
birth place (the black hole) to the much larger scales (the radiation phase). I argue that the
jet emission is result of dissipation in the jet through the process
of magnetic reconnection; a process similar to the one that powers the
solar flares. I will cover my team's latest insights on how
the magnetic reconnection in the jet plasma accounts, from
first principles, for the “emitting blobs” commonly invoked when
modeling the jet flares. Finally, I will discuss the latest developments
on the closely related and exciting field of gravitational-wave,
electromagnetic radiation Astrophysics.

Host: Alexander Tchekhovskoy 

Speaker Schedule

Keywords: Physics, Astronomy, colloquium