119219712
Non-conformal hydrodynamics in Einstein-dilaton theory
A bstractIn the Einestein-dilaton theory with a Liouville potential parameterized by η, we find a Schwarzschild-type black hole solution. This black hole solution, whose asymptotic geometry is described by the warped metric, is thermodynamically stable only for 0 ≤ η < 2. Applying the gauge/gravity duality, we find that the dual gauge theory represents a non-conformal thermal system with the equation of state depending on η. After turning on the bulk vector fluctuations with and without a dilaton coupling, we calculate the charge diffusion constant, which indicates that the life time of the quasi normal mode decreases with η. Interestingly, the vector fluctuation with the dilaton coupling shows that the DC conductivity increases with temperature, a feature commonly found in electrolytes.
116599063
Hawking fluxes and covariant anomalies
A non-destructive, direct method and apparatus for producing stretch blow molded articles having at least one physical dimension within a preselected range. The apparatus includes an injection mold defining an injection mold interior surface having a first differentially dimensioned portion disposed at a preselected location thereon and capable of producing a parison having a parison exterior surface including a first marker formed by contact with the first differentially dimensioned portion, and a stretch blow mold defining a stretch blow mold interior surface having a second differentially dimensioned portion disposed at a predetermined location thereon and capable of producing the article from the parison including a second marker formed by contact with the second differentially dimensioned portion. Relative position of the first marker with respect to the second marker indicates whether a dimension is within a preselected range. The method includes injection molding a parison so that a parison exterior surface includes a first marker disposed at a preselected position thereon and formed by contact with a first differentially dimensioned portion disposed at a preselected location on an injection mold interior surface, and stretch blow molding an article from the parison so that an article exterior surface includes a second marker disposed at a predetermined position thereon and formed by contact with a second differentially dimensioned portion disposed at a predetermined location on a stretch blow mold interior surface.
118387184
Higher order WKB corrections to black hole entropy in brick wall formalism
We calculate the statistical entropy of a quantum field with an arbitrary spin propagating on the spherical symmetric black hole background by using the brick wall formalism at higher orders in the WKB approximation. For general spins, we find that the correction to the standard Bekenstein–Hawking entropy depends logarithmically on the area of the horizon. Furthermore, we apply this analysis to the Schwarzschild and Schwarzschild–AdS(dS) black holes and discuss our results.
13913623
Hawking fluxes, back reaction and covariant anomalies
Starting from the chiral covariant effective action approach of Banerjee and Kulkarni (2008 Phys. Lett. B 659 827), we provide a derivation of the Hawking radiation from a charged black hole in the presence of gravitational back reaction. The modified expressions for charge and energy flux, due to the effect of one-loop back reaction are obtained.
119246679
Modified dispersion relations and the response of the rotating Unruh-DeWitt detector
We study the response of a rotating monopole detector that is coupled to a massless scalar field which is described by a nonlinear dispersion relation in flat spacetime. Since it does not seem to be possible to evaluate the response of the rotating detector analytically, we resort to numerical computations. Interestingly, unlike the case of the uniformly accelerated detector that has been considered recently, we find that defining the transition probability rate of the rotating detector poses no difficulties. Further, we show that the response of the rotating detector can be computed exactly (albeit, numerically) even when it is coupled to a field that is governed by a nonlinear dispersion relation. We also discuss the response of the rotating detector in the presence of a cylindrical boundary on which the scalar field is constrained to vanish. While superluminal dispersion relations hardly affect the standard results, we find that subluminal dispersion relations can lead to relatively large modifications.
18639894
Nonconservation of energy-momentum tensor in classical Liouville theory
where Ah is the area of the horizon. In this context, the classical Liouville theory [4] has gained considerable importance owing to the work of Solodukhin [5]. He showed that the computation of the black hole entropy can be carried out at the classical level. He observed that the 4-dimensional Einstein-Hilbert action can be reduced to an effective 2-dimensional theory, with fixed boundary conditions on the horizon, by performing a dimensional reduction with the ansatz of spherical symmetry and writing the metric in conformally flat form. This action can then be transformed to a form similar to the classical Liouville theory which in turn admits a Virasoro algebra near the horizon with a nontrivial classical central charge. The computation of this central charge then allows to determine the black hole entropy from the Cardy formula [6]. This approach was then used to study thermodynamic properties of black hole with a bifurcate killing horizon [7]. However, it is a well known fact from general field theoretic considerations [8, 9] that a central charge is related to diffeomorphism anomaly manifested as a nonconservation of the energy-momentum tensor. This relation is discussed from quantum considerations. The central charge and the diffeomorphism anomaly reveal different manifestations of the same phenomenon – a breakdown of classical symmetry upon the process of quantisation. Since the central charge is obtained [5, 7] in a classical Liouville theory, a natural question that arises is whether, in such a theory, there is a diffeomorphism anomaly. The principal objective of this paper is to show that this is indeed true. In this paper, we show explicitly that if we consider terms in the expansion of the metric, near the horizon, beyond leading order, then it leads to a diffeomorphism anomaly which is compatible with the fact that the theory has a nontrivial classical central charge. The computation of this anomaly has in fact been done to all orders. To begin with, we consider a four-dimensional spherically symmetric metric of the form
121351649
Detection of Magnetospheric X-Ray Pulsation from the Millisecond Pulsar B1821–24
We report the first clear detection of X-ray pulsation of magnetospheric origin from a millisecond pulsar, PSR B1821-24, with the Advanced Satellite for Cosmology and Astrophysics. The photon arrival time shows a periodicity of 3.05 ms period, as observed in the radio band. The observed X-ray pulse is double peaked. The pulses are characterized by a sharp temporal profile and hard power-law spectrum with a phase-averaged photon index of ~1.9. These two features are quite similar to the X-ray/γ-ray pulses from the Crab pulsar and characteristic of the nonthermal emission from the magnetosphere of the neutron star, but contradictory to the thermal emission from its surface. Since this pulsar has physical parameters completely different from those of young pulsars, we expect these observations to provide significant constraints on models of pulsar magnetospheric emission, which have been developed mostly based on the observations of young pulsars.
1981738
Optical Observations of the Isolated Neutron Star RX J0720.4–3125
RX J0720.423125 is an unidentified bright, soft X-ray source that shows pulsations at an 8.39 s period and has a thermal spectrum. We present deep B- and R-band images of its X-ray localization. We find one possible counterpart in the X-ray error box, with magnitudes and . The very high B 5 26.6 5 0.2 R 5 26.9 5 0.3 X-ray‐to‐optical flux ratio confirms that this object is an isolated neutron star. We discuss possible models, and we conclude that only two are consistent with the data and at the same time are able to draw from a large enough population to make finding one nearby likely. In our opinion, the second criterion provides a stringent constraint but appears to have been ignored so far. The first model, suggested earlier, is that RX J0720.423125 is a weakly magnetized neutron star accreting from the interstellar medium. The second is that it is a relatively young, highly magnetized neutron star, a “magnetar,” which is kept hot by magnetic field decay.
218626274
Time-Dependent Optical Spectroscopy of GRB 010222: Clues to the GRB Environment1
Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible with the generous financial support of the W.M. Keck Foundation Astronomy Department, Columbia University, 550 West 120th Street, New York, NY 10027 California Institute of Technology, Palomar Observatory 105-24, Pasadena, CA 91125 Infrared Processing and Analysis Center, 100-22 California Institute of Technology, 105-24, Pasadena, CA 91125 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 National Radio Astronomy Observatory, Socorro, NM 87801
50841333
A Strong, Broad Absorption Feature in the X-Ray Spectrum of the Nearby Neutron Star RX J1605.3+3249
We present X-ray spectra taken with XMM-Newton of RX J1605.3+3249, the third brightest in the class of nearby thermally emitting neutron stars. In contrast to what is the case for the brightest object, RX J1856.5-3754, we find that the spectrum of RX J1605.3+3249 cannot be described well by a pure blackbody, but shows a broad absorption feature at 27 ? (0.45 keV). With this, it joins the handful of isolated neutron stars for which spectral features arising from the surface have been detected. We discuss possible mechanisms that might lead to the features, as well as the overall optical to X-ray spectral energy distribution, and compare the spectrum with what is observed for the other nearby thermally emitting neutron stars. We conclude that we may be observing absorption due to the proton cyclotron line, as was suggested for the other sources, but weakened because of the strong-field quantum electrodynamics effect of vacuum resonance mode conversion.
14827593
No Planet Left Behind: Investigating Planetary Diversity and Architecture with SIM Lite
The evidence is mounting that star formation necessarily involves planet formation. We clearly have a vested interest in finding other Earths but a true understanding of planet formation requires completing the census and mapping planetary architecture in all its grandeur and diversity. Here, we show that a 2000-star survey undertaken with SIM Lite will uniquely probe planets around B-A-F stars, bright and binary stars and white dwarfs. In addition, we show that the high precision of SIM Lite allows us to gain unique insights into planet formation via accurate measurements of mutual inclinations.