On the Possibility of the Detection of Extinct Radio Pulsars

We explore the possibilities for detecting pulsars that have ceased to radiate in the radio band. We consider two models: the model with hindered particle escape from the pulsar surface (first suggested by Ruderman and Sutherland 1975) and the model with free particle escape (Arons 1981; Mestel 1999). In the model with hindered particle escape, the number of particles that leave the pulsar magnetosphere is small and their radiation cannot be detected with currently available instruments. At the same time, for the free particle escape model, both the number of particles and the radiation intensity are high enough for such pulsars to be detectable with the presently available receivers such as GLAST and AGILE spacecrafts. It is also possible that extinct radio pulsars can be among the unidentified EGRET sources.Comment: 5 pages, 1 figure corrected version of the paper that was published in Astronomy Letter

The Multicolor Panoramic Photometer-Polarimeter with high time resolution based on the PSD

Multicolor Panoramic Photometer-Polarimeter (MPPP) with a time resolution of 1 microsecond has been built based on a PSD and used at the 6-meter telescope in SAO (Russia). The device allows registration of the photon fluxes in four photometric bands simultaneously and finding values of 3 Stokes parameters. MPPP consists of Position-Sensitive Detector (PSD), acquisition MANIA-system, polarization unit and a set of dichroic filters. MPPP gives a possibility of detecting photons in 2 pupils with a size of 10 - 15 arc sec centered on the object and comparison star positions simultaneously. The first half of the object photon flux passes through the phase rotating plate and polarizer, and the second one through the polarizer alone. MPPP registers in each of the 4 filters four images of the object with different orientations of polarization plane and one image of a comparison star. It allows measuring instantaneous Stokes parameters. The main astrophysical problems to be solved with MPPP are as follows: investigation of optical pulsars; study of GRB phenomenon in the optical range; searching for single black holes; study of fast variability of X-ray binaries. As an illustration of MPPP use, the results of observations at the 6-meter telescope of Crab pulsar and soft gamma repeater are presented.Comment: 3 pages, 7 figures, to be published in Nuclear Instruments & Methods in Physics Researc

Short wavelength quantum electrodynamical correction to cold plasma-wave propagation

The effect of short wavelength quantum electrodynamic (QED) correction on plasma-wave propagation is investigated. The effect on plasma oscillations and on electromagnetic waves in an unmagnetized as well as a magnetized plasma is investigated. The effects of the short wavelength QED corrections are most significant for plasma oscillations and for extraordinary modes. In particular, the QED correction allow plasma oscillations to propagate, and the extra-ordinary mode looses its stop band. The significance of our results is discussed.Comment: 12 pages, 5 figure

Peculiar objects in the birthplaces of radio pulsars -- stellar-mass black hole candidates

We perform a search for stellar-mass black hole candidates in the spatial regions with increased probability of their occurrence, isolated based on the evolutionary scenarios for compact objects originating in disrupted binaries. We analyze the sources located in these regions with available spectral or photometric data, as well as measured proper motions and distances. Nine objects that exhibit characteristics corresponding to theoretical predictions for isolated black holes are marked for further study as black hole candidates

Spin solitons in magnetized pair plasmas

A set of fluid equations, taking into account the spin properties of the electrons and positrons in a magnetoplasma, are derived. The magnetohydrodynamic limit of the pair plasma is investigated. It is shown that the microscopic spin properties of the electrons and positrons can lead to interesting macroscopic and collective effects in strongly magnetized plasmas. In particular, it is found that new Alfvenic solitary structures, governed by a modified Korteweg-de Vries equation, are allowed in such plasmas. These solitary structures vanish if the quantum spin effects are neglected. Our results should be of relevance for astrophysical plasmas, e.g. in pulsar magnetospheres.Comment: 7 page

GRBs with optical afterglow and known redshift: a statistical study

We present a correlation between two intrinsic parameters of GRB optical afterglows. These are the isotropic luminosity at the maximum of the light curve (Lpeak) and the time-integrated isotropic energy (Eiso) radiated after the observed maximum. We test the correlation between the logarithms of (Eiso) and (Lpeak) and finally we value the effect of the different samples of GRBs in according with the first optical observation reduced to proper time.Comment: To be published in the proceedings of the conference "SWIFT and GRBs: Unveiling the Relativistic Universe", Venice, June 5-9, 200