天体物理学
We discuss the expansion velocities of different elements in the ejecta of the intermediate-z SNe Ia discovered as a part of the International Time Programme (ITP) project ``Omega and Lambda from Supernovae and the Physics of Supernova…
We present a method for studying the proximity effect and the density structure around redshift z=2-3 quasars. It is based on the probability distribution of Lyman-alpha pixel optical depths and its evolution with redshift. We validate the…
We are using computer models to explore the observational sensitivity to changes in atmospheric and surface properties, and the detectability of biosignatures, in the globally averaged spectra and light-curves of the Earth. Using AIRS…
The dynamic evolution of the baryonic intergalactic medium (IGM) caused by the underlying dark matter gravity is governed by the Navier-Stokes equations in which many cooling and heating processes are involved. However, it has long been…
Modern Terrestrial Cerenkov Telescopes and Array Scintillators facing the Horizons may soon reveal far Cosmic Rays or nearer PeVs-EeVs Neutrino Showers Astronomy. Indeed UHE neutrino interactions in air, leading to Horizontal Showers, may…
Type Ia supernovae (SNe Ia) provide us with a unique tool for measuring extragalactic distances and determining cosmological parameters. As a result, the precise and effective calibration for peak luminosities of SNe Ia becomes extremely…
(abridged) We investigate the properties of Giant Molecular Clouds (GMCs) in the molecule-rich galaxy M64 (NGC 4826). In M64, the mean surface density of molecular gas is 2N(H_2) ~ 10^22 over a 2 kpc region, equal to the surface densities…
We use action-angle variables to describe the basic physics of coherent scalar field oscillations in the expanding universe. These analytical mechanics methods have some advantages, like the identification of adiabatic invariants. As an…
We present a high dispersion optical spectrum of St 34 and identify the system as a spectroscopic binary with components of similar luminosity and temperature (both M3+/-0.5). Based on kinematics, signatures of accretion, and location on an…
We explore test particle orbits in the orbital plane of eccentric stellar binary systems, searching for ``invariant loops'': closed curves that change shape periodically as a function of binary orbital phase as the test particles in them…
A general quasilinear transport parameter for particle drift in arbitrary turbulence geometry is presented. The new drift coefficient is solely characterized by a nonresonant term and is evaluated for slab and two-dimensional turbulence…
We derive the expectation value for the maximum stellar mass (m_max) in an ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N. We statistically demonstrate that the upper IMF of the local massive star census…
We investigate the nature of the soft excess below 1 keV observed in AGN. We use the XMM-Newton data of the low redshift, optically bright quasar, PG 1211+143, and we compare it with the Narrow Line Seyfert 1 galaxy, 1H 0707-495, which has…
We develop a semi-analytical model that determines the evolution of the mass, position and internal structure of dark matter substructures orbiting in dark matter haloes. We apply this model to the case of the Milky Way. We focus in…
We propose magnetic proto-neutron star (PNS) winds driven by \Alfven waves as well as the neutrino heating as an appropriate site for the r-process nucleosynthesis. \Alfven waves excited by surface motions of a PNS propagate outwardly, and…
We present an 850-micron map and list of candidate sources in a 70 arcmin^2 sub-area of the Groth Strip observed using SCUBA. We initially detect 7 candidate sources with signal-to-noise ratios (SNRs) between 3.0 and 3.5 and 4 candidate…
We present an investigation of the morphology and arrival times of integrated radio pulses from the binary millisecond pulsar PSR J1022+1001. This pulsar is renowned for its poor timing properties, which have been postulated to originate…
A novel covariant formalism for the treatment of the transfer and Compton scattering of partially polarized light is presented. This was initially developed to aid in the computation of relativistic corrections to the polarization generated…
One of the robust features found in simulations of core-collapse supernovae (SNe) is the prompt neutronization burst, i.e. the first $\sim 25$ milliseconds after bounce when the SN emits with very high luminosity mainly $\nu_e$ neutrinos.…
The 2dFGRS is used in conjunction with the 2MASSXSC to study the near-IR light and stellar mass content of the local Universe. Mock galaxy catalogues, constructed from cosmological N-body simulations and semi-analytical galaxy formation…