Hyperbolic metamaterials by directed self-assembly of block copolymers

Hyperbolic materials are high uniaxial anisotropic materials that display hyperbolic dispersion with distinctive properties, including negative refraction index, control over light propagation and enhanced Purcell factor. Naturally-occurring hyperbolic materials exhibit these properties only in reduced wavelength ranges, thus limiting their implementation into integrated optical devices. In order to tune the hyperbolic dispersion over broader bandwidths, artificial structures capable to guarantee a greater flexibility, i.e. hyperbolic metamaterials (HMMs), are required. So far, the realization of HMMs that work in the visible and near-infrared wavelength regions has been limited to the out-of-plane configuration due to technological costraints in the fabrication of periodic structures at sub-wavelength dimensions. Here we propose a novel concept of HMMs working in the in-plane configuration, based on the use of block copolymers (BCPs) capable to self-assemble into highly ordered polimeric masks with nanometric feature sizes and periodicity, serving as templates for the subsequent fabrication of hybrid metal-dielectric HMMs. This new class of HMMs can be exploited for metrological applications such as the enhancement of single photon source's (SPS) emission properties

A SuperMassive Black Hole Fundamental Plane for Ellipticals

We obtain the coefficients of a new fundamental plane for supermassive black holes at the centers of elliptical galaxies, involving measured central black hole mass and photometric parameters which define the light distribution. The galaxies are tightly distributed around this mass fundamental plane, with improvement in the rms residual over those obtained from the \mbh-\sigma and \mbh-L relations. This implies a strong multidimensional link between the central massive black hole formation and global photometric properties of elliptical galaxies and provides an improved estimate of black hole mass from galaxy data.Comment: Accepted for publication in ApJ Letter

Variations of polyphenols, sugars, carotenoids, and volatile constituents in pumpkin (Cucurbita moschata) during high pressure processing: A kinetic study

High pressure processing (HPP) is an attractive technology for the preservation of vegetables with health promoting properties such as pumpkins. In this study pumpkin cubes were treated at six different pressures (100 to 600 MPa) at 20 °C for 3 min. Polyphenols (extracted both with solvent and by squeezing the residual material), carotenoids, sugars, and volatiles were evaluated. HPP at medium pressures (200–400 MPa) resulted in higher number of extractable polyphenols. Total sugars in HPP-treated samples were overall declining with increasing pressure. The total amount of carotenoids was higher in samples treated at lower pressures (100–300 MPa) and in the one at 600 MPa compared to untreated ones. Regarding volatile compounds, significant changes were observed for some aldehydes that increase after HPP application. This study revealed that treatment with intermediate pressure could ensure a higher amount of “availability” of polyphenols, carotenoids, volatiles, and total sugars in pumpkin samples

1.6 GHz VLBI Observations of SN 1979C: almost-free expansion

We report on 1.6 GHz Very-Long-Baseline-Interferometry (VLBI) observations of supernova SN 1979C made on 18 November 2002. We derive a model-dependent supernova size. We also present a reanalysis of VLBI observations made by us on June 1999 and by other authors on February 2005. We conclude that, contrary to our earlier claim of strong deceleration in the expansion, SN 1979C has been undergoing almost-free expansion ($m = 0.91\pm0.09$; $R \propto t^m$) for over 25 years.Comment: 4 pages, 4 figures; submitted to A&A on 14 May 2009. Accepted on 7 Jul 200

A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies

The masses of supermassive black holes correlate almost perfectly with the velocity dispersions of their host bulges, M(BH) ~ sigma^alpha, where alpha =4.8 +/- 0.5$. The relation is much tighter than the relation between M(BH) and bulge luminosity, with a scatter no larger than expected on the basis of measurement error alone. Black hole masses estimated by Magorrian et al. (1998) lie systematically above the M(BH)-sigma relation defined by more accurate mass estimates, some by as much as two orders of magnitude. The tightness of the M(BH)-sigma relation implies a strong link between black hole formation and the properties of the stellar bulge.Comment: ApJ, 539, L9. Rutgers Astrophysics Preprint Series No. 274 This version is slightly modified to fit within the ApJL page limit

Binary black hole merger gravitational waves and recoil in the large mass ratio limit

Spectacular breakthroughs in numerical relativity now make it possible to compute spacetime dynamics in almost complete generality, allowing us to model the coalescence and merger of binary black holes with essentially no approximations. The primary limitation of these calculations is now computational. In particular, it is difficult to model systems with large mass ratio and large spins, since one must accurately resolve the multiple lengthscales which play a role in such systems. Perturbation theory can play an important role in extending the reach of computational modeling for binary systems. In this paper, we present first results of a code which allows us to model the gravitational waves generated by the inspiral, merger, and ringdown of a binary system in which one member of the binary is much more massive than the other. This allows us to accurately calibrate binary dynamics in the large mass ratio regime. We focus in this analysis on the recoil imparted to the merged remnant by these waves. We closely examine the "antikick", an anti-phase cancellation of the recoil arising from the plunge and ringdown waves, described in detail by Schnittman et al. We find that, for orbits aligned with the black hole spin, the antikick grows as a function of spin. The total recoil is smallest for prograde coalescence into a rapidly rotating black hole, and largest for retrograde coalescence. Amusingly, this completely reverses the predicted trend for kick versus spin from analyses that only include inspiral information.Comment: 15 pages, 5 figures. Submitted to Phys. Rev.

Moving frames applied to shell elasticity

Exterior calculus and moving frames are used to describe curved elastic shells. The kinematics follow from the Lie-derivative on forms whereas the dynamics via stress-forms.Comment: 20 pages, 1 figur

Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database

We present improved black hole masses for 35 active galactic nuclei (AGNs) based on a complete and consistent reanalysis of broad emission-line reverberation-mapping data. From objects with multiple line measurements, we find that the highest precision measure of the virial product is obtained by using the cross-correlation function centroid (as opposed to the cross-correlation function peak) for the time delay and the line dispersion (as opposed to full width half maximum) for the line width and by measuring the line width in the variable part of the spectrum. Accurate line-width measurement depends critically on avoiding contaminating features, in particular the narrow components of the emission lines. We find that the precision (or random component of the error) of reverberation-based black hole mass measurements is typically around 30%, comparable to the precision attained in measurement of black hole masses in quiescent galaxies by gas or stellar dynamical methods. Based on results presented in a companion paper by Onken et al., we provide a zero-point calibration for the reverberation-based black hole mass scale by using the relationship between black hole mass and host-galaxy bulge velocity dispersion. The scatter around this relationship implies that the typical systematic uncertainties in reverberation-based black hole masses are smaller than a factor of three. We present a preliminary version of a mass-luminosity relationship that is much better defined than any previous attempt. Scatter about the mass-luminosity relationship for these AGNs appears to be real and could be correlated with either Eddington ratio or object inclination.Comment: 61 pages, including 8 Tables and 16 Figures. Accepted for publication in The Astrophysical Journa

Non-thermal Processes in Black-Hole-Jet Magnetospheres

The environs of supermassive black holes are among the universe's most extreme phenomena. Understanding the physical processes occurring in the vicinity of black holes may provide the key to answer a number of fundamental astrophysical questions including the detectability of strong gravity effects, the formation and propagation of relativistic jets, the origin of the highest energy gamma-rays and cosmic-rays, and the nature and evolution of the central engine in Active Galactic Nuclei (AGN). As a step towards this direction, this paper reviews some of the progress achieved in the field based on observations in the very high energy domain. It particularly focuses on non-thermal particle acceleration and emission processes that may occur in the rotating magnetospheres originating from accreting, supermassive black hole systems. Topics covered include direct electric field acceleration in the black hole's magnetosphere, ultra-high energy cosmic ray production, Blandford-Znajek mechanism, centrifugal acceleration and magnetic reconnection, along with the relevant efficiency constraints imposed by interactions with matter, radiation and fields. By way of application, a detailed discussion of well-known sources (Sgr A*; Cen A; M87; NGC1399) is presented.Comment: invited review for International Journal of Modern Physics D, 49 pages, 15 figures; minor typos corrected to match published versio