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HOW TO WEIGH A AND OTHER ADVENTURES IN QUASAR PHYSICS

Vikram Singh WHAT IS A BLACK HOLE? A black hole is an object whose is so powerful that not even can escape it. NO ESCAPE

• Nothing can escape from within the because nothing can go faster than light.

• No escape means there is no more contact with something that falls in. It increases the hole , changes the spin or charge, but otherwise loses its identity.

BLACK HOLES DON’T SUCK! ESCAPE VELOCITY

Initial kinetic Final gravitational = potential energy

(Escape velocity)2 G  (mass) = 2 (radius) The event horizon of a 3MSun black hole is also about as big as a small city. “GARGANTUA” FROM INTERSTELLAR

100 Million Solar THEORETICAL PARADIGM • (millions to billions of solar masses) • Powered by an disk. • Jet mechanisms proposed, but very uncertain. • Also, an “obscuring torus” seems to be present. (Unified models apply here.) FROM OUR TO THE GALACTIC CORE

Groups at Max Planck and UCLA have been observing the center of the for over two decades, tracing the orbits of . The mass of the central dark object lurking there is about 4 million solar masses. WHAT MAKES AN AGN ACTIVE?

Need a supply of gas to feed to the black hole Supermassive Black holes from 1 million to >1 billion solar masses! (Scales as a few percent of bulge mass) Collisions disturb regular orbits of stars and gas clouds Could feed more gas to the central region Galactic orbits were less organized as were forming, also recall the “hierarchical” galaxy formation Expect more gas to flow to central region when galaxies are young => Quasars (“quasar epoch” around z=2 to z=3) All galaxies have massive black holes in them They are just less active now because gas supply is less ACCRETION DISKS

Black hole is “active” only if gas is present to spiral into it Isolated stars just orbit black hole same as they would any other mass Gas collides, tries to slow due to , and so spirals in (and heats up) Conservation of angular momentum causes gas to form a disk as it spirals in BLACK HOLES POWERING ACTIVE GALAXIES: SEYFERTS AND QUASARS BLACK HOLES POWERING ACTIVE GALAXIES: SEYFERTS AND QUASARS 3C31

Red = radio Blue = visible MANY VIEWS OF ACTIVE GALAXY CENTAURUS A TAKING A STEP BACK TO FUNDAMENTALS: ARGUMENTS FOR BLACK HOLES IN AGNS • Energy Considerations • Nuclear in excess of 1013 • Gravitational release capable of converting on order 10% rest mass to energy • Rapid Variability • Timescales < 1 day imply very small source • Radio Jet Stability implies large, stable mass with large angular momentum HOW CAN WE MEASURE MASSES IN SPACE?

REMEMBER NEWTON’S VERSION OF KEPLER’S THIRD LAW VIRIAL MASS ESTIMATES • M = f (r ΔV2 / G) • r = scale length of region • ΔV is the velocity dispersion • f is a factor of order unity dependent upon geometry and kinematics

• Estimates therefore require size scales and velocities, and verification to avoid pitfalls (eg: radiative acceleration). MEASURING BLACK HOLE MASSES IN “NEARBY” GALAXIES

• Sagittarius A* in the Milky Way

• Masers in NGC 4258, a few others

• Spatially Resolved Gas or Stellar Dynamics Using the Hubble Space (HST) THE “M-SIGMA” RELATION

Black Hole Masses are about 0.1% of the central mass (a big surprise to theorists) and tightest correlation is with the stellar velocity dispersion (after Gebhardt et al. 2000). BLACK HOLE MASS FROM QUASAR SPECTRA

f f M = V 2 R = FWHM 2L1/2 BH G G

e.g., Vestergaard et al. (2006, 2009)

α

H

)

β

λ

H

log(F

C IV C Mg II Mg

Rest λ (Angstroms) HYDROGEN BETA and OXYGEN [III] FORBIDDEN LINES SDSS: THE LARGEST SKY SURVEY IN HUMAN HISTORY VLA: THE , NM RADIO MAPS OF QUASARS Wills and Browne (1986)

Face On

Edge On Runnoe et al. (2013a)

Face On Face On

Edge On Edge On Brotherton, M.S., Singh, V., Runnoe, J.C., 2015

How to look for Hβ-based black hole mass orientation bias when C IV is not available? Use stellar velocity dispersion, here estimated for about 400 radio-loud quasars with z < 0.75 from [O III] FWHM in SDSS spectra. Log R from FIRST. Sample shows strong correlation, but a little weird compared to Wills & Browne (1986).

Edge On Face On NEW PHYSICS

• Discovery of a new subset of supermassive black holes with accretion disks moving at 10% the ! • We’re moving closer to a Unified model for AGN and Galaxies, in general. Perhaps a Main Sequence for galaxies? • Further understanding of the formation and evolution of galaxies and the role of dark in providing structure to the . • Problem with gravity on large scales??? • Lots of stuff to work on still! ACKNOWLEDGEMENTS

• Prof. Michael S. Brotherton for being my best friend and mentor. It took us two years and quite a few beers to finish this project. • Dr. Jessie Runnoe (Mike’s former grad student) for always being there when I needed help and for being a good friend. • Wyoming EPSCoR for their grant (summer 2014) that helped me put the hours I needed to get this done and not go broke! • SPS and the Physics Dept. for funding to presenting my research at the 225th AAS Conference in Seattle, WA. • And … To the great minds that have laid the foundation for us to conquer the universe. We are all children, indeed!