1162741
Low-Mass X-Ray Binary as the Progenitor of PSR J1713 + 0747
We have calculated the evolution of low-mass X-ray binaries that leads to the formation of the binary radio pulsars like PSR J1713+0747. We show that the mass transfer is most likely to be nonconservative, due to unstable disk accretion, to account for the mass of PSR J1713+0747, which is close to its initial value. We assume that part of the lost material from the binary may form a circumbinary disk, and find that it can significantly influence the mass transfer processes. We briefly discuss the implications of the circumbinary disks on the evolution of low-mass X-ray binaries and the formation of low-mass binary pulsars.
119458784
An Analysis of the X-Ray Emission from the Supernova Remnant 3C 397
The ASCA SIS and ROSAT PSPC spectral data of the supernova remnant 3C 397 are analyzed with a two-component nonequilibrium ionization model. In addition, the ASCA SIS0 and SIS1 spectra are fitted simultaneously in an equilibrium case. The resulting values of the hydrogen column density yield a distance of ~8 kpc to 3C 397. It is found that the hard X-ray emission, containing S and Fe Kα lines, arises primarily from the hot component, while most of the soft emission, composed mainly of Mg, Si, and Fe L lines and continuum, is produced by the cool component. The emission measures suggest that the remnant evolves in a cloudy medium and imply that the supernova progenitor might not be a massive early-type star. The cool component is approaching ionization equilibrium. The ages estimated from the ionization parameters and dynamics are all much greater than the previous determination. We restore the X-ray maps using the ASCA SIS data and compare them with the ROSAT HRI and the NRAO VLA Sky Survey 20 cm maps. The morphology with two bright concentrations suggests a bipolar remnant encountering a denser medium in the west.
117111053
QUARK-ABNORMAL NEUTRON STARS
By using the equation of the state given by Freedman and MeLerran for quark state and that given by us for abnormal neutron state with abnormal protonsts, we have explored the models of stars with interior in quark state and outlayer in abnormal neutron state, and arrived at the conclusion that there possibly exist stable quark-abnormal neutron stars.
118512199
Systematic analysis of the $D_{J}(2580)$, $D_{J}^{*}(2650)$, $D_{J}(2740)$, $D_{J}^{*}(2760)$, $D_{J}(3000)$ and $D_{J}^{*}(3000)$ in $D$ meson family
In this work, we tentatively assign the charmed mesons $D_{J}(2580)$, $D_{J}^{*}(2650)$, $D_{J}(2740)$, $D_{J}^{*}(2760)$, $D_{J}(3000)$ and $D_{J}^{*}(3000)$ observed by the LHCb collaboration according to their spin-parity and masses, then study their strong decays to the ground state charmed mesons plus light pseudoscalar mesons with the $^{3}P_{0}$ model. According to these study, we assigned the $D_{J}^{*}(2760)$ as the $1D\frac{5}{2}3^{-}$ state, the $D_{J}^{*}(3000)$ as the $1F\frac{5}{2}2^{+}$ or $1F\frac{7}{2}4^{+}$ state, the $D_{J}(3000)$ as the $1F\frac{7}{2}3^{+}$ or $2P\frac{1}{2}1^{+}$ state in the $D$ meson family. As a byproduct, we also study the strong decays of $2P\frac{1}{2}0^{+}$,$2P\frac{3}{2}2^{+}$, $3S\frac{1}{2}1^{-}$, $3S\frac{1}{2}0^{-}$ etc, states, which will be helpful to further experimentally study mixings of these $D$ mesons.
197485150
Searching for New Topological Types of Majorana Fermions from Boundary-bulk Correspondence of Topological Insulators/Superconductors
Majorana fermions (MFs) are particles that are their own anti-particles and may satisfy non-Abelian statistics. For the past ten years, a kind of MFs have been theoretically predicted in one-dimensional superconducting models without the time-reversal symmetry (TRS), which has recently intrigued a huge experimental interest to search for this type of exotic particles. Here we report our theoretical discoveries, including (i) a general and quantitative relation between topological stabilities of Fermi surfaces (FSs) and topological insulators(TIs)/superconductors(TSCs) is rigorously established; (ii) based on (i), we find four topologically distinct types of MFs in fermionic systems that have at least the particle-hole symmetry (PHS); (iii) apart from the existing one type, three new types of topologically nontrivial gapless edge-modes (MFs) are revealed for the first time in one dimensional finite systems with both TP and (iv) all kinds of candidate models that potentially have MFs are presented, opening a wider door for searching MFs experimentally.
121131777
Physics counterpart of quasiconformal transformation, two-dimensional quantum gravity and their symmetries☆
Abstract By using the Gelfand-Dikii bracket of the second kind, we present infinite dimensional symmetries of quasiconformal diffeomorphisms whose special case gives infinite dimensional symmetries of the Virasoro algebra. The physics counterpart of quasiconformal transformation is 2D induced gravity in the light-cone metric whose SL (2, R ) symmetry is reexplored and its quantization is also performed by using the method of conformal field theory.
119266949
MULTIBAND STUDIES OF THE OPTICAL PERIODIC MODULATION IN THE X-RAY BINARY SAX J1808.4–3658 DURING ITS QUIESCENCE AND 2008 OUTBURST
We report on time-resolved optical imaging of the X-ray binary SAX J1808.4-3658 during its quiescent state and 2008 outburst. The binary, containing an accretion-powered millisecond pulsar, has a large sinusoidal-like modulation in its quiescent optical emission. We employ a Markov chain Monte Carlo technique to fit our multi-band light curve data in quiescence with an irradiated star model, and derive a tight constraint of 50(-5)(+6) deg on the inclination angle i of the binary system. The pulsar and its companion are constrained to have masses of 0.97(-0.22)(+0.31) M-circle dot and 0.04(-0.01)(+0.02) M-circle dot (both 1 sigma ranges), respectively. The dependence of these results on the measurements of the companion's projected radial velocity is discussed. We also find that the accretion disk had nearly constant optical fluxes over a similar to 500 day period in the quiescent state our data covered, but started brightening 1.5 months before the 2008 outburst. Variations in modulation during the outburst were detected in our four observations made 7-12 days after the start of the outburst, and a sinusoidal-like modulation with 0.2 mag amplitude changed to have a smaller amplitude of 0.1 mag. The modulation variations are discussed. We estimate the albedo of the companion during its quiescence and the outburst, which was approximately 0 and 0.8 (for isotropic emission), respectively. This large difference probably provides additional evidence that the neutron star in the binary turns on as a radio pulsar in quiescence.
119219570
A model of low-frequency quasi-periodic oscillations in black hole X-ray binaries
A model of low-frequency quasi-periodic oscillations (LFQPOs) of black hole X-ray binaries (BHXBs) is proposed based on the perturbed magnetohydrodynamic equations of an accretion disk. It turns out that the LFQPO frequencies of some BHXBs can be fitted by the frequencies of the toroidal Alfven wave oscillation corresponding to the maximal radiation flux. In addition, the positive correlation of the LFQPO frequencies with the radiation flux from an accretion disk is well interpreted.