Nature of cyclical changes in the timing residuals from the pulsar B1642-03

We report an analysis of timing data for the pulsar B1642-03 (J1645-0317) gathered over the 40-year time span between 1969 and 2008. During this interval, the pulsar experienced eight glitch-like events with a fractional increase in the rotation frequency Deltanu/nu=(0.9-2.6)x10^{-9}. We have revealed two important relations in the properties of these peculiar glitches. The first result shows that there is a strong linear correlation between the amplitude of the glitch and the time interval to the next glitch. The second result shows that the amplitude of the glitches is modulated by a periodic large-scale sawtooth-like function. As a result of this modulation, the glitch amplitude varies discretely from glitch to glitch with a step of 1.5x10^{-9} Hz in the range (2.4-6.9)x10^{-9} Hz. The post-glitch time interval also varies discretely with a step of about 600 days in the range 900-2700 days. An analysis of the data showed that three modulation schemes with modulation periods of 43 years, 53 years and 60 years are possible. The best model is the 60-year modulation scheme including 12 glitches. We make a conclusion that the nature of the observed cyclical changes in the timing residuals from PSR B1642-03 is a continuous generation of peculiar glitches whose amplitudes are modulated by a periodic large-scale sawtooth-like function. As the modulation function is periodical, the picture of cyclical timing residuals will be exactly repeated in each modulation period or every 60 years.Comment: 26 pages, 9 figures. Accepted for publication in the Astrophysical Journa

Observations of three slow glitches in the spin rate of the pulsar B1822-09

Three slow glitches in the rotation rate of the pulsar B1822-09 were revealed over the 1995-2004 interval. The slow glitches observed are characterized by a gradual increase in the rotation frequency with a long timescale of several months, accompanied by a rapid decrease in the magnitude of the frequency first derivative by 1-2 per cent of the initial value and subsequent exponential increase back to its initial value on the same timescale. The cumulative fractional increase in the pulsar rotation rate for the three glitches amounts to Delta_nu/nu ~ 7 10^{-8}.Comment: 11 pages, 3 figures. Accepted for publication in MNRA

Evidence for Free Precession in the Pulsar B1642-03

We present an analysis of the timing data of the pulsar B1642-03, collected over a span of 30 years between 1969 and 1999. During this interval, the timing residuals exhibit cyclical changes with amplitude varying from 15 ms to 80 ms and spacing of maxima varying from 3 years to 7 years. Interpretation of these observed cyclical changes in terms of free precession suggests a wobble angle of about 0.8 degrees.Comment: 9 pages, 5 figures. Accepted for publication in Ap

Phase and Intensity Distributions of Individual Pulses of PSR B0950+08

The distribution of the intensities of individual pulses of PSR B0950+08 as a function of the longitudes at which they appear is analyzed. The flux density of the pulsar at 111 MHz varies strongly from day to day (by up to a factor of 13) due to the passage of the radiation through the interstellar plasma (interstellar scintillation). The intensities of individual pulses can exceed the amplitude of the mean pulse profile, obtained by accumulating 770 pulses, by more than an order of magnitude. The intensity distribution along the mean profile is very different for weak and strong pulses. The differential distribution function for the intensities is a power law with index n = -1.1 +- 0.06 up to peak flux densities for individual pulses of the order of 160 Jy

Avalanche dynamics of radio pulsar glitches

We test statistically the hypothesis that radio pulsar glitches result from an avalanche process, in which angular momentum is transferred erratically from the flywheel-like superfluid in the star to the slowly decelerating, solid crust via spatially connected chains of local, impulsive, threshold-activated events, so that the system fluctuates around a self-organised critical state. Analysis of the glitch population (currently 285 events from 101 pulsars) demonstrates that the size distribution in individual pulsars is consistent with being scale invariant, as expected for an avalanche process. The waiting-time distribution is consistent with being exponential in seven out of nine pulsars where it can be measured reliably, after adjusting for observational limits on the minimum waiting time, as for a constant-rate Poisson process. PSR J0537$-$6910 and PSR J0835$-$4510 are the exceptions; their waiting-time distributions show evidence of quasiperiodicity. In each object, stationarity requires that the rate $\lambda$ equals $- \epsilon \dot{\nu} /$, where $\dot{\nu}$ is the angular acceleration of the crust, $$ is the mean glitch size, and $\epsilon\dot{\nu}$ is the relative angular acceleration of the crust and superfluid. There is no evidence that $\lambda$ changes monotonically with spin-down age. The rate distribution itself is fitted reasonably well by an exponential for $\lambda \geq 0.25 {\rm yr^{-1}}$. For $\lambda < 0.25 {\rm yr^{-1}}$, its exact form is unknown; the exponential overestimates the number of glitching pulsars observed at low $\lambda$, where the limited total observation time exercises a selection bias.Comment: Accepted for publication in the Astrophysical Journa

The Crustal Rigidity of a Neutron Star, and Implications for PSR 1828-11 and other Precession Candidates

We calculate the crustal rigidity parameter, b, of a neutron star (NS), and show that b is a factor 40 smaller than the standard estimate due to Baym & Pines (1971). For a NS with a relaxed crust, the NS's free-precession frequency is directly proportional to b. We apply our result for b to PSR 1828-11, a 2.5 Hz pulsar that appears to be precessing with period 511 d. Assuming this 511-d period is set by crustal rigidity, we show that this NS's crust is not relaxed, and that its reference spin (roughly, the spin for which the crust is most relaxed) is 40 Hz, and that the average spindown strain in the crust is 5 \times 10^{-5}. We also briefly describe the implications of our b calculation for other well-known precession candidates.Comment: 44 pages, 10 figures, submitted to Ap

The Formation of Morphological Structures of Carbon and Oxide Silicon Nanoparticles

The concept morphostructure formations nanosized individuals on the basis of carbon and quartz is offered. Under offered circuit in “the first stage” substances are generated by atoms – “elementary individuals”. They - form “simple morphostructures”, for example, fullerenes, film and a one-wall carbon tube. They have, at the best the two-dimensional structural order. The second stage of growth morphostructures is connected to formation of more complex of “elementary particles” on the basis of the approximated rounded molecules. They - form “simple morphostructures”, for example, fullerenes, film and carbon tube also. The third stage - clusters. Clusters, similarly to atoms and molecules, can form cyclic formations (oligomer/polymers), crystals and can enter structure of the mixed constructions of a layer. They can form also simple morphostructures, for example, fullerenes, film and carbon tube. The fourth stage - compact formations of polymer and so on

Quartz Particles Electron-Microscopic Investigations Modified by Mechanochemical Processing

There were taken and analyzed electron-microscopic images of quartz particles after mechanochemical processing in mill-activator with different organic modifiers. It was stated that quartz surface suffers serious changes the peculiarities of which are defined by used modifiers. Quartz particle has a complex flaky morphology. Friable surface layers represent as carbonic element-organic formations with ferrous additives. The change of particle's surface layers are responsible to modified quartz physicochemical properties transfer