Intrinsic Brightness Temperature of Compact Radio Sources at 86 GHz

We present results on the intrinsic brightness temperature of a sample of compact radio sources observed at 86 GHz using the Global Millimeter VLBI Array. We use the observed brightness temperatures at 86 GHz and the observed superluminal motions at 15 GHz for the sample in order to constrain the characteristic intrinsic brightness temperature of the sample. With a statistical method for studying the intrinsic brightness temperatures of innermost jet cores of compact radio sources, assuming that all sources have the same intrinsic brightness temperature and the viewing angles of their jets are around the critical value for the maximal apparent speed, we find that sources in the sample have a characteristic intrinsic brightness temperature, $T_{\rm 0} = 4.8^{+2.6}_{-1.5}\times 10^{9}$ K, which is lower than the equipartition temperature for the condition that the particle energy equals to the magnetic field energy. Our results suggest that the VLBI cores seen at 86 GHz may be representing a jet region where the magnetic field energy dominates the total energy in the jet.Comment: 9 pages, 4 figures, one table, to appear in JKAS. Corrections made for typos and Journal's further request

Schwinger Effect, Hawking Radiation and Gauge-Gravity Relation

We present a unified picture for the Schwinger effect and the Hawking radiation and address the gauge-gravity relation and the dS-AdS duality issue at the one-loop level. We propose a thermal interpretation for the Schwinger effect in an (A)dS space and in an Reissner-Nordstr\"{o}m black hole. The emission of charged particles from the near-extremal charged black hole is proportional to the Schwinger effect in an AdS and to another Schwinger effect in a Rindler space accelerated by the surface gravity.Comment: Latex 10 pages, 1 figure, invited talk at International Conference on Gravitation and Cosmology, KITPC, CAS, May 4-8, 201

Quasi-local charges and asymptotic symmetry generators

The quasi-local formulation of conserved charges through the off-shell approach is extended to cover the asymptotic symmetry generators. By introducing identically conserved currents which are appropriate for asymptotic Killing vectors, we show that the asymptotic symmetry generators can be understood as quasi-local charges. We also show that this construction is completely consistent with the on-shell method.Comment: 19 pages; v2 typos fixe

Canonical energy and hairy AdS black holes

We propose the modified version of the canonical energy which was introduced originally by Hollands and Wald. Our construction depends only on the Euler-Lagrange expression of the system and thus is independent of the ambiguity in the Lagrangian. After some comments on our construction, we briefly mention on the relevance of our construction to the boundary information metric in the context of the AdS/CFT correspondence. We also study the stability of three-dimensional hairy extremal black holes by using our construction.Comment: 1+28 pages, plain LaTeX; v2: typos fixed; v3 version to appear in PR