Coexistence of black holes and a long-range scalar field in cosmology

The exactly solvable scalar hairy black hole model (originated from the modern high-energy theory) is proposed. It turns out that the existence of black holes (BH) is strongly correlated to global scalar field, in a sense that they mutually impose bounds upon their physical parameters like the BH mass (lower bound) or the cosmological constant (upper bound). We consider the same model also as a cosmological one and show that it agrees with recent experimental data; additionally, it provides a unified quintessence-like description of dark energy and dark matter.Comment: 4 pages, 4 figure

Detecting a Lorentz-Violating Field in Cosmology

We consider cosmology in the Einstein-aether theory (the generally covariant theory of gravitation coupled to a dynamical timelike Lorentz-violating vector field) with a linear aether-Lagrangian. The 3+1 spacetime splitting approach is used to derive covariant and gauge invariant perturbation equations which are valid for a general class of Lagrangians. Restricting attention to the parameter space of these theories which is consistent with local gravity experiments, we show that there are tracking behaviors for the aether field, both in the background cosmology and at linear perturbation level. The primordial power-spectrum of scalar perturbations in this model is shown to be the same that predicted by standard general relativity. However, the power-spectrum of tensor perturbation is different from that in general relativity, but has a smaller amplitude and so cannot be detected at present. We also study the implications for late-time cosmology and find that the evolution of photon and neutrino anisotropic stresses can source the aether field perturbation during the radiation and matter dominated epochs, and as a result the CMB and matter power spectra are modified. However these effects are degenerate with respect to other cosmological parameters, such as neutrino masses and the bias parameter in the observed galaxy spectrum.Comment: 13 pages, 3 figures; modified version to appear in Physical Review

Parametrized tests of post-Newtonian theory using Advanced LIGO and Einstein Telescope

General relativity has very specific predictions for the gravitational waveforms from inspiralling compact binaries obtained using the post-Newtonian (PN) approximation. We investigate the extent to which the measurement of the PN coefficients, possible with the second generation gravitationalwave detectors such as the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and the third generation gravitational-wave detectors such as the Einstein Telescope (ET), could be used to test post-Newtonian theory and to put bounds on a subclass of parametrized-post-Einstein theories which differ from general relativity in a parametrized sense. We demonstrate this possibility by employing the best inspiralling waveform model for nonspinning compact binaries which is 3.5PN accurate in phase and 3PN in amplitude. Within the class of theories considered, Advanced LIGO can test the theory at 1.5PN and thus the leading tail term. Future observations of stellar mass black hole binaries by ET can test the consistency between the various PN coefficients in the gravitational-wave phasing over the mass range of 11-44 Msun. The choice of the lower frequency cut off is important for testing post-Newtonian theory using the ET. The bias in the test arising from the assumption of nonspinning binaries is indicated.Comment: 18 pages, 11 figures, Matches with the published versio

Characterization of infectious and defective cloned avian hepadnavirus genomes

The infectivity in vivo, replication competence in vitro, and expression of viral genes of several molecularly cloned duck hepatitis B virus (DHBV) genomes were investigated. In addition, replication competence, core protein expression, and secretion of viral proteins were investigated for a grey heron hepatitis B virus genome. Except two, all DHBV isolates tested induced a systemic infection in Pekin ducks when injected as cloned viral DNA into the liver. After transfection of chicken hepatoma cells, both defective DHBV genomes expressed intracellular nucleocapsid and pre-S envelope proteins and secreted DHBs/pre-S particles into the medium. One of the defective DHBV genomes and HHBV produced within the cells replicative intermediates encapsidated in core particles and secreted virions, whereas the other defective DHBV genome did not and was unable to efficiently encapsidate the RNA pregenome. Comparative sequence analysis was performed to identify potential amino acid changes in viral proteins of both defective DHBV genomes. The data obtained demonstrate that most cloned avian hepadnaviruses are infectious or replication competent and suggest defects in envelope, polymerase or encapsidation function, respectively, in two cloned DHBV genomes

The Correlation Between Galaxy HI Linewidths and K' Luminosities

The relationship between galaxy luminosities and rotation rates is studied with total luminosities in the K' band. Extinction problems are essentially eliminated at this band centered at 2.1 micron. A template luminosity-linewidth relation is derived based on 65 galaxies drawn from two magnitude-limited cluster samples. The zero-point is determined using 4 galaxies with accurately known distances. The calibration is applied to give the distance to the Pisces Cluster (60 Mpc) at a redshift in the CMB frame of 4771 km/s. The resultant value of the Hubble Constant is 81 km/s/Mpc. The largest sources of uncertainty arises from the small number of zero-point calibrators at this time at K' and present application to only one cluster.Comment: 13 pages including 5 figures and 2 tables. Accepted for publication in Astrophysical Journa