Explore the fascinating realm of supermassive black holes in this comprehensive lecture by G. Srinivasan from the Raman Research Institute. Delve into the history of quasar discovery and their incredible luminosity, learn about radio galaxies with powerful relativistic jets, and understand how observations led to the conclusion that active galactic nuclei are powered by supermassive black holes. Examine the evolution of our understanding of these cosmic giants, from early radio astronomy techniques to modern very long baseline interferometry. Discover the physics behind relativistic jets, superluminal motion, and accretion onto supermassive black holes. Investigate the evidence for their existence in various galaxies, including our own Milky Way. Gain insights into the groundbreaking work of the Event Horizon Telescope and its imaging of the M87 black hole shadow. Discuss the formation and stability of supermassive black holes, and contemplate future prospects in X-ray interferometry and gravitational wave detection. This pedagogical talk assumes no prior knowledge and concludes with a Q&A session.
The Realm of Supermassive Black Holes - Lecture 13
International Centre for Theoretical Sciences via YouTube
Overview
Syllabus
Date: Wed, 26 June 2019, 10:00 to
Neutron Stars and Black Holes Lecture -13: The Realm of the Supermassive Black Holes
Realm of the Supermassive Black Holes
The Radio Galaxy Cygnus A
Cliff top Interferometer
Intensity Interferometer
Hanbury-Brown & Twiss Intensity Interferometer
Michelson Interferometer
Intensity Interferometer of Hanbury-Brown
The Radio Galaxy Cygnus A
Quest for high angular resolution
Origin of the radio lobes
Jets discovered in Cygnus A
Very Long Baseline Interferometry
The Global VLBI-Array
CYGNUS A
One sided jets
M 87 The giant elliptical
NGC 6251
Proper time:
Doppler Shift
Doppler favoritism
Imagine a black hole at position A ejecting a blob in direction making an angle theta to the observer. Let the blob be moving with velocity v.
Superluminal motion
Apparent transverse velocity as a function of beta and theta
Superluminal Motion in the M87 Jet
To achieve sub-milli arc second resolution one uses intercontinental baseline interferometry.
Relativistic jets
Energy content in the radio lobes
Energy content
The central engines
Eddington Luminosity Limit
Thompson scattering cross section:
Variability of Quasars
Supermassive Black Holes
Accretion onto Supermassive Black Holes
Evidence for supermassive Black Holes
NGC 4258
Mega MASERS in NGC 4258
Stars orbiting the Galactic Centre Black Hole
Black Hole at the centre of Milky Way
The giant black hole at the center of M 87
M87 Base of Jet
Angular resolution required to resolve the event horizon of the central BH
VLBI at 1.3 mm
Event Horizon Telescope
VLBI at 1.3 mm with the EHT
Environment of the Black Hole
What does one expect to see with the EHT?
Motion of light near a nonrotating BH
What does one expect to see?
Comparison with simulations suggests that the torus is rotating CLOCKWISE around the spin axis of the BH
Summary of the conclusions
Has General Relativity finally been verified to a satisfactory extent?
S. Chandrasekhar:
X-Ray interferometry - in the near future - and, to a lesser extent, space based GW detectors hold out tantalizing prospects
Formation of supermassive black holes
Mergers
How did the original BHs form?
Supermassive stars
Stability of Matter
Stability of a star in General Relativity
Stability of a supermassive star in General Relativity
Next Lecture - Universe or Multiverse?!
Q&A
Taught by
International Centre for Theoretical Sciences
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