Browsing FAS Scholarly Articles by Keyword "gravitation"

Now showing items 1-11 of 11

    • Central Charge for \(AdS_2\) Quantum Gravity 

      Hartman, Thomas; Strominger, Andrew E. (Institute of Physics, 2009)
      Two-dimensional Maxwell-dilaton quantum gravity on \(AdS_2\) with radius \(\ell\) and a constant electric field \(E\) is studied. In conformal gauge, this is equivalent to a CFT on a strip. In order to maintain consistent ...

    • Dynamical Compactification from de Sitter Space 

      Carroll, Sean M.; Johnson, Matthew C.; Randall, Lisa (Springer, 2009)
      We show that \(D\)-dimensional de Sitter space is unstable to the nucleation of non-singular geometries containing spacetime regions with different numbers of macroscopic dimensions, leading to a dynamical mechanism of ...

    • The Event Horizon of M87 

      Broderick, Avery E.; Narayan, Ramesh; Kormendy, John; Perlman, Eric S.; Rieke, Marcia J.; Doeleman, Sheperd S. (IOP Publishing, 2015)
      The 6 × 109M⊙ supermassive black hole at the center of the giant elliptical galaxy M87 powers a relativistic jet. Observations at millimeter wavelengths with the Event Horizon Telescope have localized the emission from the ...

    • General relativistic magnetohydrodynamic simulations of Blandford-Znajek jets and the membrane paradigm 

      Penna, R. F.; Narayan, Ramesh; Sadowski, A. (Oxford University Press (OUP), 2013)
      Recently it has been observed that the scaling of jet power with black hole spin in galactic X-ray binaries is consistent with the predictions of the Blandford-Znajek (BZ) jet model. These observations motivate us to revisit ...

    • Quantum Criticality and Black Holes 

      Sachdev, Subir; Müller, Markus (Institute of Physics, 2009)
      Many condensed matter experiments explore the finite temperature dynamics of systems near quantum critical points. Often, there are no well-defined quasiparticle excitations, and so quantum kinetic equations do not describe ...

    • The Shakura-Sunyaev viscosity prescription with variable (r) 

      Penna, R. F.; Sadowski, A.; Kulkarni, A. K.; Narayan, Ramesh (Oxford University Press (OUP), 2012)
      Almost all hydrodynamic accretion disc models parametrize viscosity with the dimensionless parameter α. There is no detailed model for α, so it is usually taken to be a constant. However, global simulations of magnetohydrodynamic ...

    • Three-dimensional general relativistic radiation magnetohydrodynamical simulation of super-Eddington accretion, using a new code HARMRAD with M1 closure 

      McKinney, J. C.; Tchekhovskoy, A.; Sadowski, A.; Narayan, Ramesh (Oxford University Press (OUP), 2014)
      Black hole (BH) accretion flows and jets are dynamic hot relativistic magnetized plasma flows whose radiative opacity can significantly affect flow structure and behavior. We describe a numerical scheme, tests, and an ...

    • Unbound Debris Streams and Remnants Resulting From the Tidal Disruptions of Stars by Supermassive Black Holes 

      Guillochon, James F.; McCourt, Michael; Chen, Xian; Johnson, Michael D.; Berger, Edo (American Astronomical Society, 2016)
      The kinetic energy of a star in orbit about a supermassive black hole is a significant fraction of its rest mass energy when its periapse is comparable to its tidal radius. Upon its destruction, a fraction of this energy ...

    • VLBI for Gravity Probe B. I. Overview 

      Shapiro, Irwin Ira; Bartel, N.; Bietenholz, M. F.; Lebach, D. E.; Lestrade, J.-F.; Ransom, R. R.; Ratner, M. I. (IOP Publishing, 2012)
      We describe the NASA/Stanford gyroscope relativity mission, Gravity Probe B (GP-B), and provide an overview of the following series of six astrometric and astrophysical papers that report on our radio observations and ...

    • Warped \(AdS_3\) Black Holes 

      Anninos, Dionysios; Li, Wei; Padi, Megha; Song, Wei; Strominger, Andrew E. (Institute of Physics, 2009)
      Three dimensional topologically massive gravity (TMG) with a negative cosmological constant \(-\ell^{-2}\) and positive Newton constant \(G\) admits an \(AdS_3\) vacuum solution for any value of the graviton mass \(\mu\). ...

    • Wrapped \(M2/M5\) Duality 

      Guica, Monica; Strominger, Andrew E. (Institute of Physics, 2009)
      A microscopic accounting of the entropy of a generic 5D supersymmetric rotating black hole, arising from wrapped \(M2\)-branes in Calabi-Yau compactified \(M\)-theory, is an outstanding unsolved problem. In this paper we ...