Giant pulses from the millisecond pulsar PSR B1937+214

We have detected giant pulses from the millisecond pulsar PSR B1937+214 at the lowest frequency of 112 MHz. The observed flux density at the pulse peak is ～40 000 Jy, which exceeds the average level by a factor of 600. Pulses of such intensity occur about once per 300 000 periods. The brightness temperature of the observed giant pulses is T _B≈10³⁵ K. We estimated the pulse broadening by interstellar scattering to be τ_sc=3–10 ms. Based on this estimate and on published high-frequency measurements of this parameter, we determined the frequency dependence of the pulse broadening by scattering: τ_sc(f)=25 × (f/100)^?4.0±02.     

Giant radio pulses from the millisecond pulsar PSR B1937+21 at 327 MHz

Seven giant radio pulses were recorded from the millisecond pulsar PSR B1937+21 during ≈8.1 min observation by the Ooty Radio Telescope (ORT) at 326.5 MHz. Although sparse, these observations support most of the giant pulse behaviour reported at higher radio frequencies (430 to 2380 MHz). Within the main component of the integrated profile, they are emitted only in a narrow (≲47 μs) window of pulse phase, close to its peak. This has important implications for doing super-high precision timing of PSR B1937+21 at low radio frequencies.     

Peculiarities of giant pulses from the crab pulsar at frequencies of 594 and 2228 MHz

We present the results of our simultaneous observations of giant pulses from the Crab pulsar B0531+21 at frequencies of 594 and 2228 MHz with a high (62.5 ns) time resolution. The pulse broadening by scattering was found to be 25 and 0.4 µs at 594 and 2228 MHz, respectively. We obtained the original giant-pulse profiles compensated for interstellar scattering. The measured profile widths at the two frequencies are approximately equal, ≈0.5 µs; i.e., the giant pulses are narrower than the integrated profile by a factor of about 1000. We detected an extremely high brightness temperature of radio emission, T_b≥10³⁶ K radio emission, which is higher than the previous estimates of this parameter by five orders of magnitude. The decorrelation bandwidth of the radio-spectrum diffraction distortions has been determined for this pulsar for the first time: 10 kHz at 594 MHz and 300 kHz at 2228 MHz.     

Detection of giant pulses from the pulsar PSR B1112+50

We detected giant pulses from the pulsar PSR B1112+50. A pulse with an intensity that is a factor of 30 or more higher than the intensity of the average pulse is encountered approximately once in 150 observed pulses. The peak flux density of the strongest pulse is about 180 Jy. This value is a factor of 80 higher than the peak flux density of the average pulse. The giant pulses are narrower than the average profile by approximately a factor of 5 and they cluster about the center of the average profile.     

Detection of giant pulses from the pulsar PSR B0031-07

Giant pulses have been detected from the pulsar PSR B0031-07. A pulse with an intensity higher than that of the average pulse by a factor of 50 or more is encountered approximately once per 300 observed periods. The peak flux density of the strongest pulse was 530 Jy, which is a factor of 120 higher than the peak flux density of the average pulse. The giant pulses are a factor of 20 narrower than the integrated profile and are clustered about its center.     

Detection of giant radio pulses from the pulsar PSR B0656+14

Giant pulses (GPs) have been detected from the pulsar PSR B0656 + 14. A pulse that is more intense than the average pulse by a factor of 120 is encountered approximately once in 3000 observed periods of the pulsar. The peak flux density of the strongest pulse, 120 Jy, is a factor of 630 higher than that of the average pulse. The GP energy exceeds the energy of the average pulse by up to a factor of 110, which is comparable to that for other known pulsars with GPs, including the Crab pulsar and the millisecond pulsar PSR B1937+21. The giant pulses are a factor of ～6 narrower than the average pulse and are clustered at the head of the average pulse. PSR B0656+14 along with PSR B0031-07, PSR B1112+50, and PSR J1752+2359 belong to a distinctive group of pulsars in which GPs have been detected without any extremely strong magnetic field on the light cylinder.     

Search for giant pulses of radio pulsars at frequency 111 MHz with LPA radio telescope

We have used the unique low frequency sensitivity of the Large Phased Array(LPA) radio telescope of Pushchino Radio Astronomy Observatory to collect a dataset consisting of single pulse observations of second period pulsars in the Northern Hemisphere. During observation sessions in 2011–2017, we collected data on 71 pulsars at a frequency of 111 MHz using a digital pulsar receiver. We have discovered Giant Radio Pulses(GRPs) from pulsars B0301+09 and B1237+25, and confirmed earlier reported generation of anomalously strong(probable giant) pulses from B1133+16 in a statistically significant dataset. Data for these pulsars and from B0950+08 and B1112+50, earlier reported as pulsars generating GRPs, were analyzed to evaluate their behavior over long time intervals. It was found that the statistical criterion(power-law spectrum of GRP distribution of energy and peak flux density) seems not to be strict for pulsars with a low magnetic field at their light cylinder. Moreover, spectra of some of these pulsars demonstrate unstable behavior with time and have a complex multicomponent shape. In the dataset for B0950+08, we have detected the strongest GRP from a pulsar with a low magnetic field at its light cylinder ever reported, having a peak flux density as strong as 16.8 kJy.     

Timing results for the binary millisecond pulsar J1640+2224 obtained on the RT-64 radio telescope in Kalyazin

We present the timing results for the binary millisecond pulsar J1640+2224 obtained with the RT-64 radio telescope (TNA-1500, Special Design Bureau, Moscow Power Engineering Institute) at the Kalyazin Observatory (Astrospace Center of the Lebedev Institute of Physics) in 1997–2002. We obtained Keplerian and post-Keplerian parameters of the binary system, which allowed us to estimate an upper limit for the energy density of the stochastic gravitational-wave background radiation at very low frequencies.     

An empirical model for the polarization of pulsar radio emission

We present an empirical model for single pulses of radio emission from pulsars based on Gaussian probability distributions for relevant variables. The radiation at a specific pulse phase is represented as the superposition of radiation in two (approximately) orthogonally polarized modes (OPMs) from one or more subsources in the emission region of the pulsar. For each subsource, the polarization states are drawn randomly from statistical distributions, with the mean and the variance on the Poincaré sphere as free parameters. The intensity of one OPM is chosen from a lognormal distribution, and the intensity of the other OPM is assumed to be partially correlated, with the degree of correlation also chosen from a Gaussian distribution. The model is used to construct simulated data described in the same format as real data: distributions of the polarization of pulses on the Poincaré sphere and histograms of the intensity and other parameters. We concentrate on the interpretation of data for specific phases of PSR B0329+54 for which the OPMs are not orthogonal, with one well defined and the other spread out around an annulus on the Poincaré sphere at some phases. The results support the assumption that the radiation emerges in two OPMs with closely correlated intensities, and that in a statistical fraction of pulses one OPM is invisible.     

Polarization observations of four southern pulsars at 1560 MHz

We present some interesting results from the mean pulse polarization observations of four southern pulsars made at the Australian National Radio Astronomy Observatory, Parkes, using the 64-m telescope in June and July, 1988. The 2 × 16 × 5 MHz filter system from Jodrell Bank has proved excellent in de-dispersing the pulse signals and measuring their polarization properties. We give the data for the four pulsars in some detail and discuss their spectral behaviour.     

The interpulse radio emission of the pulsar PSR 1919+21 at the frequencies 16.7-38 MHz

Results of observations of the pulsar PSR 1919+21 in the range 16.7 to 25 MHz and at 38 MHz are compared. Similarities have been disclosed in the signal wave form, the number of interpulses, and other features.     

PSR J1453+1902 and the radio luminosities of solitary versus binary millisecond pulsars

We present 3 yr of timing observations for PSR J1453+1902, a 5.79-ms pulsar discovered during a 430-MHz drift-scan survey with the Arecibo telescope. Our observations show that PSR J1453+1902 is solitary and has a proper motion of  8 ±  2  mas yr⁻¹. At the nominal distance of 1.2 kpc estimated from the pulsar's dispersion measure, this corresponds to a transverse speed of  46 ± 11   km s⁻¹  , typical of the millisecond pulsar population. We analyse the current sample of 55 millisecond pulsars in the Galactic disc and revisit the question of whether the luminosities of isolated millisecond pulsars are different from their binary counterparts. We demonstrate that the apparent differences in the luminosity distributions seen in samples selected from 430-MHz surveys can be explained by small-number statistics and observational selection biases. An examination of the sample from 1400-MHz surveys shows no differences in the distributions. The simplest conclusion from the current data is that the spin, kinematic, spatial and luminosity distributions of isolated and binary millisecond pulsars are consistent with a single homogeneous population.     

Broadband observations of the transient X-ray pulsar SAX J2103.5+4545

We investigated the optical, X-ray, and gamma-ray variability of the pulsar SAX J2103.5+4545. Our timing and spectral analyses of the X-ray and gamma-ray emissions from the source using RXTE and INTEGRAL data show that the shape of its spectrum in the energy range 3–100 keV is virtually independent of its intensity and the orbital phase. Based on XMM-Newton data, we accurately (5″) localized the object and determined the optical counterpart in the binary. We placed upper limits on the variability of the latter in the Hα line on time scales of the orbital and pulse periods, respectively.     

A Parkes radio telescope study of giant pulses from PSR J1823–3021A

We report on 685-MHz observations of PSR J1823–3021A using the Parkes radio telescope. A total of 120 giant pulses (GPs) were found by searching for spiky emission at 16-μs time resolution. The energies of these pulses follow a power law that has a very steep exponent of −3.1. This means that the emission mechanism that gives rise to the GPs almost always produces pulses that only have moderate energies. The profile formed by adding all the GPs has components that are narrower and more widely separated than the profile formed from all pulses. Aberration and retardation of emission from a corotating volume mean that components emitted at high altitude will have asymmetric phases compared to those emitted at low altitude. By assuming that the components of the pulse profile form conal pairs, we use this effect to limit the GPs to be emitted no higher than 4 km above ordinary emission. The arrival times of the GPs are well modelled by Poisson statistics at time-scales around 100 s. We report a GP with spikes of emission at the phases of both components. The probability of two independent GPs occurring within a single pulse period is     , so an interpretation can be conjectured that the two pulses are not independent. This may mean that the magnetosphere can remain in a state that is susceptible to discrete 'giant' emission events for as long as 2 ms.