The termination shock of a magnetar wind: a possible origin of gamma-ray burst X-ray afterglow emission

Context: Swift observations suggest that the X-ray afterglow emission of some gamma-ray bursts (GRB) may have internal origins, and the conventional external shock (ES) cannot be the exclusive source of the afterglow emission. Aims: If the central compact objects of some GRBs are millisecond magentars, the magnetar winds could play an important role in the (internal) X-ray afterglow emission, which is our focus here. Methods: The dynamics and the synchrotron radiation of the termination shock (TS) of the magmnetar winds, as well as the simultaneous GRB ES, are investigated by considering the magnetization of the winds. Results: As a result of the competition between the emission of the wind TS and the GRB ES, two basic types of X-ray afterglows are predicted, i.e., the TS-dominated and the ES-dominated types. Moreover, our results also show that both of the two types of afterglows have a shallow-decay phase and a normal-decay one, as observed by the \textit{Swift} satellite. This indicates that some observed X-ray afterglows could be (internally) produced by the magnetar winds, but not necessarily GRB ESs.Comment: 5 pages, 3 figure

Magnetic fileds of coalescing neutron stars and the luminosity function of short gamma-ray burst

Coalescing neutron star binaries are believed to be the most reliable sources for ground-based detectors of gravitational waves and likely progenitors of short gamma-ray bursts. In the process of coalescence, magnetic fields of neutron stars can induce interesting observational manifestations and affect the form of gravitational wave signal. In this papaer we use the population synthesis method to model the expected distribution of neutron star magnetic fields during the coalescence under different assumptions on the initial parameters of neutron stars and their magnetic field evolution. We discuss possible elecotrmagnetic phenomena preceding the coalescence of magnetized neutron star binaries and the effect of magnetic field on the gravitational wave signal. We find that a log-normal (Gaussian in logarithms) distribution of the initial magnetic fields of neutron stars, which agrees with observed properties of radio pulsars, produces the distribution of the magnetic field energy during the coalescence that adequately describes the observed luminosity function of short gamma-ray bursts under different assumptions on the field evolution and initial parameters of neutron stars. This agreement lends further support to the model of coalescing neutron star binaries as progenitors of gamma-ray bursts.Comment: v.2, LATEX, 25 pages, inc. 7 ps figures, Astron. Lett., in press. Typos corrected, reference adde

Fourth Contribution on Late Eocene Amber Silken Fungus Beetles: A New Baltic Amber Species of Atomaria (Coleoptera, Clavicornia, Cryptophagidae)

Atomaria gedanicola Lyubarsky et Perkovsky, sp. n., a new cryptophagid species from Baltic amber is described. The new species is the first recorded Eocene Atomariinae. The new species is similar to A. fuscipes Gyllenhal. It differs from the latter in having pronotum flat, posterior angles of pronotum obtuse, and antenna short. The record of A. gedanicola syninclused with Ceratopogon biting midge supports the Late Eocene age of the Baltic amber, for the Holarctic affinities of both taxa are incompatible with the paratropical climate characteristic of the Mid-European Middle Eocene.Описан новый вид криптофагид из балтийского янтаря — Atomaria gedanicola Lyubarsky et Perkovsky, sp. n. Это первый эоценовый представитель Atomariinae. Новый вид сходен с A. fuscipes Gyllenhal, от которого отличается плоским пронотумом с тупыми задними углами и короткими антеннами. Нахождение A. gedanicola в сининклюзе с мокрецом Ceratopogon указывает на позднеэоценовый возраст балтийского янтаря, так как голарктическая приуроченность обоих таксонов несовместима с паратропическим климатом среднего эоцена Средней Европы

About chaotization mechanisms of the distributed dynamical systems which are close to discrete

The investigations of stochastization mechanisms of distributed dynamical systems (DDS) are developed not so complete as stochastization of dynamical systems with concentrated parameters (CDS). Therefore the corresponding DDS which is close (in one or other sense) to the CDS under consideration is used. Such substitution means some roughening of an initial problem. However, there are such important stochastization mechanisms understanding properties, which are connected with system “distributivity” on principle. In this paper the conception of a proximity to the CDS is introduced for one particular class of the DDS. It is shown that such kind of systems has two stochastization mechanisms, one of which is common to the DDS and the corresponding CDS. Another stochastization mechanism inherent in DDS disappears under transition from DDS to CDS