1,297 research outputs found
Slowly rotating black holes in the Horava-Lifshitz gravity
We investigate slowly rotating black holes in the Ho\v{r}ava-Lifshitz (HL)
gravity. For and , we find a slowly rotating black
hole of the Kehagias-Sfetsos solution in asymptotically flat spacetimes. We
discuss their thermodynamic properties by computing mass, temperature, angular
momentum, and angular velocity on the horizon.Comment: 12 pages, no figures, version to appear in EPJ
Phase transitions for the Lifshitz black holes
We study possibility of phase transitions between Lifshitz black holes and
other configurations by using free energies explicitly. A phase transition
between Lifshitz soliton and Lifshitz black hole might not occur in three
dimensions. We find that a phase transition between Lifshitz and BTZ black
holes unlikely occurs because they have different asymptotes. Similarly, we
point out that any phase transition between Lifshitz and black branes unlikely
occurs in four dimensions since they have different asymptotes. This is
consistent with a necessary condition for taking a phase transition in the
gravitational system, which requires the same asymptote.Comment: 19 pages, 7 figures, a revised version to appear in EPJ
Nonpropagation of massive mode on AdS2 in topologically massive gravity
Making use of Achucarro-Ortiz (AO) type of dimensional reduction, we study
the topologically massive gravity with a negative cosmological constant on AdS2
spacetimes. For a constant dilaton, this two-dimensional model also admits
three AdS2 vacuum solutions, which are related to two AdS3 and warped AdS3
backgrounds with an identification upon uplifting three dimensions. We carry
out the perturbation analysis around these backgrounds to find what is a
physically propagating field. However, it turns out that there is no
propagating massive mode on AdS2 background, in contrast to the Kaluza-Klein
(KK) type of dimensional reduction. We note that two dimensionally reduced
actions are different and thus, the non-equivalence of their on-shell
amplitudes is obtained.Comment: 19 pages, version to appear in EPJ
The Connection between Star-Forming Galaxies, AGN Host Galaxies and Early-Type Galaxies in the SDSS
We present a study of the connection between star-forming galaxies, AGN host
galaxies, and normal early-type galaxies in the Sloan Digital Sky Survey
(SDSS). Using the SDSS DR5 and DR4plus data, we select our early-type galaxy
sample in the color versus color-gradient space, and we classify the spectral
types of the selected early-type galaxies into normal, star-forming, Seyfert,
and LINER classes, using several spectral line flux ratios. We investigate the
slope in the fundamental space for each class of early-type galaxies and find
that there are obvious differences in the slopes of the fundamental planes
(FPs) among the different classes of early-type galaxies, in the sense that the
slopes for Seyferts and star-forming galaxies are flatter than those for normal
galaxies and LINERs. This may be the first identification of the systematic
variation of the FP slope among the subclasses of early-type galaxies. The
difference in the FP slope might be caused by the difference in the degree of
nonhomology among different classes or by the difference of gas contents in
their merging progenitors. One possible scenario is that the AGN host galaxies
and star-forming galaxies are formed by gas-rich merging and that they may
evolve into normal early-type galaxies after finishing their star formation or
AGN activities.Comment: 5 pages with emulateapj, 2 figures, accepted for publication in the
Astrophysical Journal Letter
Linearized Gravity in Isotropic Coordinates in the Brane World
We solve the Einstein equations in the Randall-Sundrum framework using an
isotropic ansatz for the metric and obtain an exact expression to first order
in the gravitational coupling. The solution is free from metric singularities
away from the source and it satisfies the Israel matching condition on a
straight brane. At distances far away from the source and on the physical brane
this solution coincides with the 4-D Schwarzschild metric in isotropic
coordinates. Furthermore we show that the extension of the standard
Schwarzschild horizon in the bulk is tubular for any diagonal form of the
metric while there is no restriction for the extension of the Schwarzschild
horizon in isotropic coordinates.Comment: 13 pages, plain Te
Disordered Systems and Logarithmic Conformal Field Theory
We review a recent development in theoretical understanding of the quenched
averaged correlation functions of disordered systems and the logarithmic
conformal field theory (LCFT) in d-dimensions. The logarithmic conformal field
theory is the generalization of the conformal field theory when the dilatation
operator is not diagonal and has the Jordan form. It is discussed that at the
random fixed point the disordered systems such as random-bond Ising model,
Polymer chain, etc. are described by LCFT and their correlation functions have
logarithmic singularities. As an example we will discuss in detail the
application of LCFT to the problem of random-bond Ising model in .Comment: 47 pages, latex, to appear in Int. J. of Mod. Phys. A (2003
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