13-18 December 2015
International Conference Centre Geneva
Europe/Zurich timezone

New connection between plasma conditions near black hole event horizons and outflow properties

16 Dec 2015, 16:36
Level 0, Room 23 (International Conference Centre Geneva)

Level 0, Room 23

International Conference Centre Geneva

17 Rue de Varembé, 1211 Geneva


Karri Koljonen (New York University Abu Dhabi)


Accreting black holes are responsible for producing the fastest, most powerful outflows of matter in the Universe. The formation process of powerful jets close to black holes is poorly understood, and the conditions leading to jet formation are currently hotly debated. In this talk I will present recent results that show empirical correlation between the properties of the plasma close to the black hole and the particle acceleration properties within jets launched from the central regions of accreting stellar-mass and supermassive black holes. In these sources the emission of the plasma near the black hole is characterized by a power law at X-ray energies during times when the jets are produced. We find that the photon index of this power law, which gives information on the underlying particle distribution, correlates with the characteristic break frequency in the jet spectrum, which is dependent on magnetohydrodynamical processes in the outflow. The observed range in break frequencies varies by five orders of magnitude, in sources that span nine orders of magnitude in black hole mass, revealing a similarity of jet properties over a large range of black hole masses powering these jets. This correlation demonstrates that the internal properties of the jet rely most critically on the conditions of the plasma close to the black hole, rather than other parameters such as the black hole mass or spin, and will provide a benchmark that should be reproduced by the jet formation models.

Primary author

Karri Koljonen (New York University Abu Dhabi)


Alexander van der Horst (George Washington University) Dave Russell (New York University Abu Dhabi) Federico Bernardini (New York University Abu Dhabi) James Miller-Jones (ICRAR/Curtin University) Juan Fernandez-Ontiveros (INAF/IAPS) Peter Curran (ICRAR/Curtin University) Piergiorgio Casella (INAF/Osservatorio Astronomico di Roma) Poshak Gandhi (University of Southampton) Roberto Soria (ICRAR/Curtin University) Sera Markoff (University of Amsterdam) Thomas Russell (ICRAR/Curtin University)

Presentation Materials