13,901 research outputs found
Black Hole Monodromy and Conformal Field Theory
The analytic structure of solutions to the Klein-Gordon equation in a black
hole background, as represented by monodromy data, is intimately related to
black hole thermodynamics. It encodes the "hidden conformal symmetry" of a
non-extremal black hole, and it explains why features of the inner event
horizon appear in scattering data such as greybody factors. This indicates that
hidden conformal symmetry is generic within a universality class of black
holes.Comment: 20 pages, v2 minor corrections, updated reference
The 2011 October Draconids Outburst. II. Meteoroid Chemical Abundances from Fireball Spectroscopy
On October 8, 2011 the Earth crossed dust trails ejected from comet
21P/Giacobini-Zinner in the late 19th and early 20th Century. This gave rise to
an outburst in the activity of the October Draconid meteor shower, and an
international team was organized to analyze this event. The SPanish Meteor
Network (SPMN) joined this initiative and recorded the October Draconids by
means of low light level CCD cameras. In addition, spectroscopic observations
were carried out. Tens of multi-station meteor trails were recorded, including
an extraordinarily bright October Draconid fireball (absolute mag. -10.5) that
was simultaneously imaged from three SPMN meteor ob-serving stations located in
Andalusia. Its spectrum was obtained, showing a clear evolution in the relative
intensity of emission lines as the fireball penetrated deeper into the
atmosphere. Here we focus on the analysis of this remarkable spectrum, but also
discuss the atmospheric trajectory, atmospheric penetration, and orbital data
computed for this bolide which was probably released during
21P/Giacobini-Zinner return to perihelion in 1907. The spectrum is discussed
together with the tensile strength for the October Draconid meteoroids. The
chemical profile evolution of the main rocky elements for this extremely bright
bolide is compared with the elemental abundances obtained for 5 October
Draconid fireballs also recorded during our spectroscopic campaign but observed
only at a single station. Significant chemical heterogeneity between the small
meteoroids is found as we should expect for cometary aggregates being formed by
diverse dust components.Comment: Manuscript in press in Monthly Notices of the Royal Astronomical
Society. Accepted for publication in MNRAS on April 28th, 2013 Manuscript
Pages: 28 Tables: 5 Figures: 12. Manuscript associated: "The 2011 October
Draconids outburst. I. Orbital elements, meteoroid fluxes and
21P/Giacobini-Zinner delivered mass to Earth" by Trigo-Rodriguez et al. is
also in press in the same journa
Black Hole Scattering from Monodromy
We study scattering coefficients in black hole spacetimes using analytic
properties of complexified wave equations. For a concrete example, we analyze
the singularities of the Teukolsky equation and relate the corresponding
monodromies to scattering data. These techniques, valid in full generality,
provide insights into complex-analytic properties of greybody factors and
quasinormal modes. This leads to new perturbative and numerical methods which
are in good agreement with previous results.Comment: 28 pages + appendices, 2 figures. For Mathematica calculation of
Stokes multipliers, download "StokesNotebook" from
https://sites.google.com/site/justblackholes/techy-zon
Is there a tensionless Kardar-Parisi-Zhang universality class above one dimension? An Ising model approach
The Kardar-Parisi-Zhang (KPZ) equation is a paradigm of generic scale
invariance, for which it represents a conspicuous universality class. Recently,
the tensionless case of this equation has been shown to provide a different
universality class by itself. This class describes the -- intrinsically
anomalous -- scaling of one-dimensional (1D) fronts for several physical
systems that feature ballistic dynamics. In this work, we show that the
evolution of certain 1D fronts defined for a 2D Ising system also belongs to
the tensionless KPZ universality class. Nevertheless, the Ising fronts exhibit
multiscaling, at variance with the continuous equation. The discrete nature of
these fronts provides an alternative approach to assess the dynamics for the 2D
front case (for a 3D Ising system), since the direct integration of the
tensionless KPZ equation blows up in this case. In spite of the agreement
between the 1D scaling of the Ising fronts and the tensionless KPZ equation,
the fluctuation statistics in 1D and the full behavior in 2D are strongly
conditioned by boundary effects.Comment: 9 pages, 9 figure
Warps and correlations with intrinsic parameters of galaxies in the visible and radio
From a comparison of the different parameters of warped galaxies in the
radio, and especially in the visible, we find that: a) No large galaxy (large
mass or radius) has been found to have high amplitude in the warp, and there is
no correlation of size/mass with the degree of asymmetry of the warp. b) The
disc density and the ratio of dark to luminous mass show an opposing trend:
smaller values give more asymmetric warps in the inner radii (optical warps)
but show no correlation with the amplitude of the warp; however, in the
external radii neither is there any correlation with the asymmetry. c) A third
anticorrelation arises from a comparison of the amplitude and degree of
asymmetry in the warped galaxies. Hence, it seems that very massive dark matter
haloes have nothing to do with the formation of warps but only with the degree
of symmetry in the inner radii, and are unrelated to the warp shape for the
outermost radii. Denser discs show up the same dependence.Comment: 13 pages, 2 figures, accepted to be published in A&
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