Search results for "binary [neutron star]"
showing 10 items of 544 documents
An eclipsing millisecond pulsar in the globular cluster Terzan 5
1990
WE HAVE discovered an eclipsing binary millisecond pulsar in the globular cluster Terzan 5. This, the second known eclipsing binary pulsar after PSR1957 + 20, has a pulse period of 11.56 ms and a very short orbital period of 1.8 hours. In contrast to PSR1957 + 20, where the eclipses occupy about 10 per cent of the orbital period1, the eclipse duration in this pulsar is very variable and never less than one-third of the orbital period. The pulsar is in a circular orbit of radius 0.11 light seconds, which implies a minimum companion mass of 0.089 solar masses, about four times the companion mass of PSR1957 + 20. Timing observations suggest an identification of the pulsar with a variable conti…
Accurate Period Determination of an Eclipsing Binary X-Ray Source in M33
1993
We have analyzed the time variability of one of the X-ray sources in M33 observed by both the ROSAT and Einstein Observatory telescopes. The light curve of M33 X-7 exhibits a variability pattern of high and low states, suggesting an eclipsing binary X-ray source. The data suggest a binary period P=1.78572 days (very close to that of Her X-1) and an eclipse duration of ∼0.4 days. The low phase lasts about one-fourth of the period as in Cen X-3
Inherent structure entropy of supercooled liquids
1999
We present a quantitative description of the thermodynamics in a supercooled binary Lennard Jones liquid via the evaluation of the degeneracy of the inherent structures, i.e. of the number of potential energy basins in configuration space. We find that for supercooled states, the contribution of the inherent structures to the free energy of the liquid almost completely decouples from the vibrational contribution. An important byproduct of the presented analysis is the determination of the Kauzmann temperature for the studied system. The resulting quantitative picture of the thermodynamics of the inherent structures offers new suggestions for the description of equilibrium and out-of-equilib…
Thermodynamics of supercooled liquids in the inherent structure formalism: a case study
2000
In this article we review the thermodynamics of liquids in the framework of the inherent structure formalism. We then present calculations of the distribution of the basins in the potential energy of a binary Lennard-Jones mixture as a function of temperature. The comparison between the numerical data and the theoretical formalism allows us to evaluate the degeneracy of the inherent structures in a bulk system and to estimate the energy of the lowest energy disordered state (the Kauzmann energy). We find that, around the mode-coupling temperature, the partition function of the liquid is approximated well by the product of two loosely coupled partition functions, one depending on the inheren…
Dynamical Heterogeneities Below the Glass Transition
2001
We present molecular dynamics simulations of a binary Lennard-Jones mixture at temperatures below the kinetic glass transition. The ``mobility'' of a particle is characterized by the amplitude of its fluctuation around its average position. The 5% particles with the largest/smallest mean amplitude are thus defined as the relatively most mobile/immobile particles. We investigate for these 5% particles their spatial distribution and find them to be distributed very heterogeneously in that mobile as well as immobile particles form clusters. The reason for this dynamic heterogeneity is traced back to the fact that mobile/immobile particles are surrounded by fewer/more neighbors which form an ef…
Quantitative tests of mode-coupling theory for fragile and strong glass-formers
2001
We calculate for a binary mixture of Lennard-Jones particles the time dependence of the solution of the mode-coupling equations in which the full wave vector dependence is taken into account. In addition we also take into account the short time dynamics, which we model with a simple memory kernel. We find that the so obtained solution agrees very well with the time and wave vector dependence of the coherent and incoherent intermediate scattering functions as determined from molecular dynamics computer simulations. Furthermore we calculate the wave vector dependence of the Debye-Waller factor for a realistic model of silica and compare these results with the ones obtained from a simulation o…
X-ray detection of the substellar twin 2MASS J11011926-7732383 AB
2007
2MASS J11011926-7732383 AB (hereafter 2M1101AB), located in the Cha I star forming region, is a rare wide-separation brown dwarf binary. XMM-Newton and Chandra observations of 2M1101AB have allowed us to examine the influence of physical parameters (mass, bolometric luminosity and effective temperature) on X-ray emission from a coeval pair of substellar objects. The spatial resolution of XMM-Newton is not sufficient to separate contributions from the two components in the binary. The X-ray source detected with XMM-Newton has a column density compatible with the infrared extinction of component A. On the other hand, the binary is resolved with Chandra, and the bulk of the X-ray emission is c…
Surface effects on spinodal decomposition in binary mixtures: The case with long-ranged surface fields
1997
We present detailed numerical results for phase-separation kinetics of critical binary mixtures in the vicinity of a surface that exerts a long-ranged attractive force on one of the components of the mixture. We consider surface potentials of the form $V(Z)\ensuremath{\sim}{Z}^{\ensuremath{-}n}$, where $Z$ is the distance from the surface and $n=1,2,3$. In particular, we investigate the interplay of the surface wetting layer with the dynamics of domain growth. We find that the wetting layer at the surface exhibits power-law growth with an exponent that depends on $n$, in contrast to the case with a short-ranged surface potential, where the growth is presumably logarithmic. From correlation …
Talbot array illuminators with binary phase gratings
2009
We establish that, in six different cases, binary phase gratings can be applied to implement Talbot array illuminators. Three of the six cases are reported for what is to our knowledge the first time.
Direct Observation in 3d of Structural Crossover in Binary Hard Sphere Mixtures
2016
For binary fluid mixtures of spherical particles in which the two species are sufficiently different in size, the dominant wavelength of oscillations of the pair correlation functions is predicted to change from roughly the diameter of the large species to that of the small species along a sharp crossover line in the phase diagram [C. Grodon, M. Dijkstra, R. Evans & R. Roth, J.Chem.Phys. 121, 7869 (2004)]. Using particle-resolved colloid experiments in 3d we demonstrate that crossover exists and that its location in the phase diagram is in quantitative agreement with the results of both theory and our Monte-Carlo simulations. In contrast with previous work [J. Baumgartl, R. Dullens, M. …