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.
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
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.
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.
14909136
Remarks on the generalized Chaplygin gas
We develop an action formulation for the generalized Chaplygin gas (GCG). The most general form for the nonrelativistic GCG action is derived consistent with the equation of state. We also discuss a relativistic formulation for GCG by providing a detailed analysis of the Poincare algebra.
2123399
An Unusual X-Ray Burst from the Globular Cluster M28
We report the discovery of an unusual X-ray burst from the direction of the globular cluster M28 using data acquired with ASCA. The burst was recorded by all four ASCA telescopes and displays a fast (70 ms) rise followed by an exponential decay (τ=7.5 s) and a steady afterglow that lasts between 800 and 3250 s. The image of the burst is consistent with an ASCA point source and is centered on quiescent X-ray emission from the core of M28. The burst temporal profile is similar to type I bursts emitted by accreting neutron stars of low-mass X-ray binaries (LMXBs). We argue that the burst arises from a LMXB that is located in the core of M28. The burst is unique in two ways: it is intrinsically subluminous, ~0.02LE, and more importantly it originates from a source whose quiescent luminosity is fainter than that of the known cluster bursters by 3 orders of magnitude. We suggest that this burst is from a highly magnetized neutron star accreting at a low rate. These accreting systems may account for the mysterious low-luminosity X-ray sources in globular clusters.
18977124
Initial scientific results from phase-referenced astrometry of sub-arcsecond binaries
The Palomar Testbed Interferometer has observed several binary star systems whose separations fall between the interferometric coherence length (a few hundredths of an arcsecond) and the typical atmospheric seeing limit of one arcsecond. Using phase-referencing techniques we measure the relative separations of the systems to precisions of a few tens of micro-arcseconds. We present the first scientific results of these observations, including the astrometric detection of the faint third stellar component of the kappa Pegasi system.
41205625
Five new outbursting AM CVn systems discovered by the Palomar Transient Factory
We present five new outbursting AM CVn systems and one candidate discovered as part of an ongoing search for such systems using the Palomar Transient Factory (PTF). This is the first large-area, systematic search for AM CVn systems using only large-amplitude photometric variability to select candidates. Three of the confirmed systems and the candidate system were discovered as part of the PTF transient search. Two systems were found as part of a search for outbursts through the PTF photometric data base. We discuss the observed characteristics of each of these systems, including the orbital periods of two systems. We also consider the position of these systems, selected in a colour-independent survey, in colour–colour space and compare to systems selected solely by their colours. We find that the colours of our newly discovered systems do not differ significantly from those of previously known systems, but significant errors preclude a definitive answer.
8748320
Swift J2058.4+0516: Discovery of a possible second relativistic tidal disruption flare?
We report the discovery by the Swift hard X-ray monitor of the transient source Swift J2058.4+0516 (Sw J2058+05). Our multi-wavelength follow-up campaign uncovered a long-lived (duration ≳ months), luminous X-ray (L_(X, iso) ≈ 3 × 10^(47) erg s^(–1)) and radio (νL_(ν, iso) ≈ 10^(42) erg s^(–1)) counterpart. The associated optical emission, however, from which we measure a redshift of 1.1853, is relatively faint, and this is not due to a large amount of dust extinction in the host galaxy. Based on numerous similarities with the recently discovered GRB 110328A/Swift J164449.3+573451 (Sw J1644+57), we suggest that Sw J2058+05 may be the second member of a new class of relativistic outbursts resulting from the tidal disruption of a star by a supermassive black hole. If so, the relative rarity of these sources (compared with the expected rate of tidal disruptions) implies that either these outflows are extremely narrowly collimated (θ < 1°) or only a small fraction of tidal disruptions generate relativistic ejecta. Analogous to the case of long-duration gamma-ray bursts and core-collapse supernovae, we speculate that rapid spin of the black hole may be a necessary condition to generate the relativistic component. Alternatively, if powered by gas accretion (i.e., an active galactic nucleus (AGN)), Sw J2058+05 would seem to represent a new mode of variability in these sources, as the observed properties appear largely inconsistent with known classes of AGNs capable of generating relativistic jets (blazars, narrow-line Seyfert 1 galaxies).
10764639
ASCA Discovery of an X-Ray Pulsar in the Error Box of SGR 1900+14
We present a 2-10 keV ASCA observation of the field around the soft gamma repeater SGR 1900+14. One quiescent X-ray source was detected in this observation, and it was in the SGR error box. In 2-10 keV X-rays, its spectrum may be fitted by a power law with index -2.2, and its unabsorbed flux is 9.6 × 10-12 ergs cm-2 s-1. We also find a clear 5.16 s period. The properties of the three well-studied soft gamma repeaters are remarkably similar to one another, and they provide evidence that all of them are associated with young, strongly magnetized neutron stars in supernova remnants.