A. N. Kazantsev, V. A. Potapov
Here we present results of our search for Giant Pulses(GPs) from pulsars of Northern Hemisphere. Our survey was carried out at a frequency of 111 MHz using the Large Phased Array (LPA) radio telescope. Up to now we have detected regular generation of strong pulses satisfying the criteria of GPs from 2 pulsars: B1133+16, B1237+25.
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It is conjectured that coherent re-emission of cyclotron resonance absorption could result in pulsar giant pulses. This conjecture seems reasonable as it can naturally explain the distribution of pulsars with giant pulses on the $P$-$\dot{P}$ diagram.
We used a new spectral-fitting technique to identify a subpopulation of 6 narrow-band giant pulses from the Crab pulsar out of a total of 1578. These giant pulses were detected in 77 minutes of observations with the 46-m dish at the Algonquin Radio Observatory at 400-800 MHz. The narrow-band giant pulses consist of both main- and inter-pulses, thereby being more likely to be caused by an intrinsic emission mechanism as opposed to a propagation effect. Fast Radio Bursts (FRBs) have demonstrated similar narrow-band features while only little has been observed in the giant pulses of pulsars. We r…
We present results of the investigation of the giant radio pulses (GRPs) generation rate from 5 radio pulsars (B0301+19, B0950+08, B1112+50, B1133+16, and B1237+25) and anomalous intensity pulses generation rate from B0809+74. All data used were obtained with Large Phased Array radio telescope of Pushchino Radio Astronomy Observatory at 111~MHz from 2012 to 2021. In addition to analysis of the rate of generation of bright pulses, we analyze the distribution of bright pulses in the phase of the pulsar period and search for clusters of bright pulses - several bright pulses emit in adjacent pulsa…
We have used the unique low frequency sensitivity of the Large Phased Array radio telescope of Pushchino Radio Astronomy Observatory to collect dataset of the single pulse observations of second period pulsars of the Northern hemisphere. During observational sessions of 2011 - 2017 yrs. We have collected data on 71 pulsars at 111 MHz frequency using digital pulsar receiver. We have discovered Giant Radio Pulses (GRP) from pulsars B0301+09 and B1237+25, and confirmed early reported generation of anomalously strong (probable giant) pulses from B1133+16 on statistically significant dataset. Data …
We present here the analysis of giant micropulses from the Vela pulsar. A total of 4187 giant micropulses with peak flux density $>$2.5 Jy were detected during almost 4 hours of observations carried out with the Yunnan 40-m radio telescope at 6800 MHz. Nine of the giant micropulses arrived approximately 3 to 4 ms earlier than the peak of average pulse profile, longer than that at lower frequencies. The remaining giant micropulses were clustered into three distributions which correspond to three main emission regions, including four occurring on the trailing edge of averaged profile.
In the present work we consider energy accumulation mechanism in relativistic electron-positron plasma in the magnetosphere of pulsars. Waves propagating almost across the magnetic field lines are generated that accumulate the energy of plasma particles, as the waves stay significantly long in the resonance region. The accumulated energy is transmitted in the parallel direction of the magnetic field lines as soon as the non-linear plasma processes start to operate. It is suggested that exit of the accumulated energy via waves propagating along the magnetic field lines matching the viewing angl…
A Statistical Analysis of Crab Pulsar Giant Pulse Rates
本研究基于88小时观测数据统计分析蟹状脉冲星巨脉冲速率，探讨折射闪烁校正方法，并搜索周期性及聚集模式，为理解亮单脉冲中子星提供见解。
The Crab pulsar experienced a major flare in 2010 as observed by Fermi LAT. Observations by the Hubble Space Telescope indicate that the flare was accompanied by a structural change in the anvil region of the Crab Nebula. In the framework of a photometric analysis we reconstruct the energetics of this event. Reconnection zones near the light cylinder are expected to release energy by accelerating beams of electrons, leading to flares of varying amplitude. In this case the major flare would have reduced the magnetic energy stored in the reconnection zones, and would thus have had an impact on t…
We present the results of the search for a correlation between giant radio pulses (GRPs) at 1.4 GHz and hard X-rays at 15-75 keV from the Crab pulsar. We made simultaneous ground and satellite observations of the Crab pulsar over 12 hours in three occasions in April 2010, March and September 2011, and got a sample of 1.3*10^4 main-pulse phase GRPs. From these samples we have found statistically marginal enhancement (21.5%, 2.70 sigma) of hard X-ray flux within +/- 1.5 degree phase angle of the synchronous peak of main-pulse phase GRPs. This enhancement, if confirmed, implicates that GRPs may a…
1A 0535+262 is a Be X-ray binary pulsar and one of the only galactic pulsar systems to show radio jet emission. Characterizing the very high energy emission (VHE, >100 GeV) in these extreme microquasars is critical to understanding their contribution to the origin of galactic cosmic rays. The 2020 giant outburst of this system, where X-ray fluxes exceeded 12 Crab, marked a rare opportunity to investigate the gamma-ray and rapid optical variability of these transient systems while in such an extreme state. This month of activity marked the brightest flare measured in this system. VERITAS's deve…
Many radio pulsars have stable pulse profiles, but some exhibit mode changing where the profile switches between two or more quasi-stable modes of emission. So far, these effects had only been seen in relatively slow pulsars, but we show here that the pulse profile of PSR B1957+20, a millisecond pulsar, switches between two modes, with a typical time between mode changes of only $1.7$ s (or $\sim\!1000$ rotations), the shortest observed so far. The two modes differ in both intensity and polarization, with relatively large differences in the interpulse and much more modest ones in the main puls…
We present analysis of the rate of giant radio pulses (GPs) emission from the Crab pulsar (B0531+21). Results of our 9 years daily observations with the Large Phased Array radio telescope of Pushchino Radio Astronomy Observatory at 111 MHz were used. Limited sample of 8753 strong individual pulses in 2004 observational sessions was further analysed. It was shown that the observed monthly averaged rate of GPs emission was highly unstable during the entire span of observations and changes by about two orders of magnitude for high-energy pulses. Data were further analysed to search for the possib…
The Crab Pulsar is the prime example of an emitter of giant pulses. These short, very bright pulses are thought to originate near the light cylinder, at $\sim\!1600{\rm\;km}$ from the pulsar. The pulsar's location inside the Crab Nebula offers an unusual opportunity to resolve the emission regions, using the nebula, which scatters radio waves, as a lens. We attempt to do this using a sample of 61998 giant pulses found in coherently combined European VLBI network observations at $18{\rm\;cm}$. These were taken at times of relatively strong scattering and hence good effective resolution, and fro…
Giant radio pulses (GRPs) are sporadic bursts emitted by some pulsars, lasting a few microseconds. GRPs are hundreds to thousands of times brighter than regular pulses from these sources. The only GRP-associated emission outside radio wavelengths is from the Crab Pulsar, where optical emission is enhanced by a few percent during GRPs. We observed the Crab Pulsar simultaneously at X-ray and radio wavelengths, finding enhancement of the X-ray emission by $3.8\pm0.7\%$ (a 5.4$σ$ detection) coinciding with GRPs. This implies that the total emitted energy from GRPs is tens to hundreds of times high…
Binary millisecond pulsars (MSPs) provide several opportunities for research of fundamental physics. However, finding them can be challenging. Several subdwarf B (sdB) binary systems with possible neutron star companions have been identified, allowing us to perform a targeted search for MSPs within these systems. Six sdBs with companions in the neutron star mass range, as determined from their optical light curves, were observed with the Green Bank and Westerbork radio telescopes. The data were searched for periodic signals as well as single pulses. No radio pulsations from sdB systems were de…
Irradiation effect and binary radio pulsars with giant companions
本文利用MESA恒星演化代码研究辐照效应对带有巨星伴星的双星射电脉冲星参数空间的影响，发现辐照可显著扩展其参数空间并可能使亚毫秒脉冲星伴有巨星伴星，为相关观测提供指导。
There are some similarities between bursts of repeating fast radio bursts (FRBs) and giant pulses (GPs) of pulsars. To explore possible relations between them, we study the cumulative energy distributions of these two phenomena using the observations of repeating FRB 121102 and the GPs of Crab pulsar. We find that the power-law slope of GPs (with fluence $\geq$130 Jy ms) is $2.85\pm0.10$. The energy distribution of FRB 121102 can be well fitted by a smooth broken power-law function. For the bursts of FRB 121102 above the break energy (1.22 $\times 10^{37}$ erg), the best-fitting slope is $2.90…
Measurements of the Crab Pulsar's Giant Radio Pulse Amplitude Power-Law Index Using Low-Frequency Arecibo and Green Bank Telescope Observations
本研究利用 Arecibo 和 Green Bank 望远镜在 327 MHz 和 350 MHz 频率下观测，测得 Crab 脉冲星巨射电脉冲幅度的幂律指数分别为 $-2.63 \pm 0.05$ 和 $-3.6 \pm 0.5$，结果与以往低频测量一致，为未来研究提供了参考。
Giant pulsar frequency glitches as detected in the emblematic Vela pulsar have long been thought to be the manifestation of a neutron superfluid permeating the inner crust of a neutron star. However, this superfluid has been recently found to be entrained by the crust, and as a consequence it does not carry enough angular momentum to explain giant glitches. The extent to which pulsar-timing observations can be reconciled with the standard vortex-mediated glitch theory is studied considering the current uncertainties on dense-matter properties. To this end, the crustal moment of inertia of glit…
The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project has the primary goal of detecting and characterizing low-frequency gravitational waves through high-precision pulsar timing. The mitigation of interstellar effects is crucial to achieve the necessary precision for gravitational wave detection. Effects like dispersion and scattering are more influential at lower observing frequencies, with the variation of these quantities over week-month timescales requiring high-cadence multi-frequency observations for pulsar timing projects. In this work, we utilize the dual-…
Unveiling the origin of the optical and UV emission during the 2017 giant outburst of the Galactic ULX pulsar Swift J0243.6+6124 (Corrigendum)
本勘误指出此前模拟Swift J0243.6+6124 2017年大爆发光学/紫外辐射的模型代码有误，导致Be星加热表面贡献被高估，提出加入非共面Be星盘X射线辐照效应，更新模型初步拟合效果良好。
The Crab pulsar has striking radio emission properties, with the two dominant pulse components -- the main pulse and the interpulse -- consisting entirely of giant pulses. The emission is scattered in both the Crab nebula and the interstellar medium, causing multi-path propagation and thus scintillation. We study the scintillation of the Crab's giant pulses using phased Westerbork Synthesis Radio Telescope data at 1668\,MHz. We find that giant pulse spectra correlate at only $\sim 2 \%$, much lower than the $1/3$ correlation expected from a randomized signal imparted with the same impulse resp…
The frequency dependence of normal pulsar radio emission is typically observed to be a power law, with some indications of a flattening or turnover at low frequencies ($<100$ MHz). The spectrum of the Crab pulsar's giant pulse emission has not been examined as closely. We conducted simultaneous wideband observations of the Crab pulsar, with the Parkes radio telescope and the Murchison Widefield Array, to study the spectral behaviour of its giant pulses. Our analysis shows that the mean spectral index of Crab giant pulses flattens at low frequencies, from $-2.6\pm0.5$ between the Parkes bands, …
We report on observations of giant pulses from the Crab pulsar performed simultaneously with the Parkes radio telescope and the incoherent combination of the Murchison Widefield Array (MWA) antenna tiles. The observations were performed over a duration of approximately one hour at a center frequency of 1382 MHz with 340 MHz bandwidth at Parkes, and at a center frequency of 193 MHz with 15 MHz bandwidth at the MWA. Our analysis has led to the detection of 55 giant pulses at the MWA and 2075 at Parkes above a threshold of 3.5$σ$ and 6.5$σ$ respectively. We detected 51$\%$ of the MWA giant pulses…
We discuss possible association of fast radio bursts (FRBs) with supergiant pulses emitted by young pulsars (ages $\sim$ tens to hundreds of years) born with regular magnetic field but very short -- few milliseconds -- spin periods. FRBs are extra-Galactic events coming from distances $d \lesssim 100$ Mpc. Most of the dispersion measure (DM) comes from the material in the freshly ejected SNR shell; for a given burst the DM should decrease with time. FRBs are not expected to be seen below $\sim 300 $ MHz due to free-free absorption in the expanding ejecta. A supernova might have been detected y…
Giant pulses (GPs) are extremely bright individual pulses of radio pulsar. In microbursts of Crab pulsar, which is an active GP emitter, zebra-pattern-like spectral structures are observed, which are reminiscent of the `zebra bands' that are observed in type IV solar radio flares. However, band spacing linearly increases with the band center frequency of $\sim5-30$\,GHz. In this study, we propose that the Crab pulsar GP can originate from the coherent instability of plasma near a light cylinder. Further, the growth of coherent instability can be attributed to the resonance observed between the…
We report on pulse profile decomposition analysis of a bright transient X-ray pulsar 1A 0535+262 using the broadband Insight-HXMT observations during a giant outburst of the source in 2020. We show that the observed pulse profile shape can be described in terms of a combination of two symmetric single-pole contributions for wide range of energies and luminosities for a fixed geometry defining basic geometry of the pulsar. This corresponds to a slightly distorted dipole magnetic field, i.e., one pole has to be offset by $\sim 12^{\circ}$ from the antipodal position of the other pole. We reconst…
The Crab pulsar is well-known for its anomalous giant radio pulse emission. Past studies have concentrated only on the very bright pulses or were insensitive to the faint end of the giant pulse luminosity distribution. With our new instrumentation offering a large bandwidth and high time resolution combined with the narrow radio beam of the Westerbork Synthesis Radio Telescope (WSRT), we seek to probe the weak giant pulse emission regime. The WSRT was used in a phased array mode, resolving a large fraction of the Crab nebula. The resulting pulsar signal was recorded using the PuMa II pulsar ba…
PSR J0540$-$6919 is the second-most energetic radio pulsar known and resides in the Large Magellanic Cloud. Like the Crab pulsar it is observed to emit giant radio pulses (GPs). We used the newly-commissioned PTUSE instrument on the MeerKAT radio telescope to search for GPs across three observations. In a total integration time of 5.7 hrs we detected 865 pulses above our 7$σ$ threshold. With full polarisation information for a subset of the data, we estimated the Faraday rotation measure, $\rm{RM}=-245.8 \pm 1.0$ rad m$^{-2}$ toward the pulsar. The brightest of these pulses is $\sim$ 60% linea…
We report the detection of giant pulse emission from PSR B0950+08 in 24 hours of observations made at 39.4 MHz, with a bandwidth of 16 MHz, using the first station of the Long Wavelength Array, LWA1. We detected 119 giant pulses from PSR B0950+08 (at its dispersion measure), which we define as having SNRs at least 10 times larger than for the mean pulse in our data set. These 119 pulses are 0.035% of the total number of pulse periods in the 24 hours of observations. The rate of giant pulses is about 5.0 per hour. The cumulative distribution of pulse strength $S$ is a steep power law, $N(>S)\pr…
We have studied 4265 giant pulses (GPs) from the millisecond pulsar B1937+21; the largest-ever sample gathered for this pulsar, in observations made with the Large European Array for Pulsars. The pulse energy distribution of GPs associated with the interpulse are well-described by a power law, with index $α= -3.99 \pm 0.04$, while those associated with the main pulse are best-described by a broken power law, with the break occurring at $\sim7$ Jy $μ$s, with power law indices $α_{\text{low}} = -3.48 \pm 0.04$ and $α_{\text{high}} = -2.10 \pm 0.09$. The modulation indices of the GP emission are …
Bright, short radio bursts are emitted by sources at a large range of distances: from the nearby Crab pulsar to remote Fast Radio Bursts (FRBs). FRBs are likely to originate from distant neutron stars, but our knowledge of the radio pulsar population has been limited to the Galaxy and the Magellanic Clouds. In an attempt to increase our understanding of extragalactic pulsar populations, and its giant-pulse emission, we employed the low-frequency radio telescope LOFAR to search the Andromeda Galaxy (M31) for radio bursts emitted by young, Crab-like pulsars. For direct comparison we also present…
A Simultaneous Dual-Frequency Scintillation Arc Survey of Six Bright Canonical Pulsars Using the Upgraded Giant Metrewave Radio Telescope
本文利用升级后的GMRT对六颗明亮典型脉冲星进行同时双频闪烁弧巡测，更稳健地分析了闪烁弧特性的频率依赖性，发现了不对称性与曲率的相关性，并揭示了ISM散射屏的演化特征。
Several pulsars show sudden cessation of pulsed emission, which is known as pulsar nulling. In this paper, the nulling behaviour of 15 pulsars is presented. The nulling fractions of these pulsars, along with the degree of reduction in the pulse energy during the null phase, are reported for these pulsars. A quasi-periodic null-burst pattern is reported for PSR J1738-2330. The distributions of lengths of the null and the burst phases as well as the typical nulling time scales are estimated for eight strong pulsars. The nulling pattern of four pulsars with similar nulling fraction are found to b…
We report the results obtained from a detailed timing and spectral studies of Be/X-ray binary pulsar 2S 1417-624 using data from Swift and NuSTAR observatories. The observations were carried out at the peak of a giant outburst of the pulsar in 2018. X-ray pulsations at 17.475 s were detected in the source light curves up to ~79 keV. The evolution of the pulse profiles with energy was found to be complex. A four-peaked profile at lower energies gradually evolved into a double-peak structure at higher energies. The pulsed fraction of the pulsar, calculated from the NuSTAR observation was found t…
The first station of the Long Wavelength Array (LWA1) was used to study PSR~B0031-07 with simultaneous observations at 38 and 74~MHz. We found that 158 (0.35\%) of the observed pulses at 38~MHz and 221 (0.49\%) of the observed pulses at 74~MHz qualified as giant pulses in a total of 12 hours of observations. Giant pulses are defined as having flux densities of a factor of $\geq$ 90 times that of an average pulse at 38~MHz and $\geq$ 80 times that of an average pulse at 74~MHz. The cumulative distribution of pulse strength follows a power law, with an index of $-$4.2 at 38~MHz and $-$4.9 at 74~…
We present the results of the simultaneous observation of the giant radio pulses (GRPs) from the Crab pulsar at 0.3, 1.6, 2.2, 6.7, and 8.4 GHz with four telescopes in Japan. We obtain 3194 and 272 GRPs occurring at the main pulse and the interpulse phases, respectively. A few GRPs detected at both 0.3 and 8.4 GHz are the most wide-band samples ever reported. In the frequency range from 0.3 to 2.2 GHz, we find that about 70\% or more of the GRP spectra are consistent with single power laws and the spectral indices of them are distributed from $-4$ to $-1$. We also find that a significant numbe…
We observed the Crab pulsar with the 43-m telescope in Green Bank, WV over a timespan of 15 months. In total we obtained 100 hours of data at 1.2 GHz and seven hours at 330 MHz, resulting in a sample of about 95000 giant pulses (GPs). This is the largest sample, to date, of GPs from the Crab pulsar taken with the same telescope and backend and analyzed as one data set. We calculated power-law fits to amplitude distributions for main pulse (MP) and interpulse (IP) GPs, resulting in indices in the range of 2.1-3.1 for MP GPs at 1.2 GHz and in the range of 2.5-3.0 and 2.4-3.1 for MP and IP GPs at…
High Sensitivity Beamformed Observations of the Crab Pulsar's Radio Emission
本研究利用高灵敏度的 EVN 波束形成数据分析了蟹状星云脉冲星的射电辐射，探测到 65951 个巨脉冲并揭示了其能量分布、到达时间聚集与抑制规律及微弱回波特征。
Detection of giant pulses from the transitional millisecond pulsar J1227$-$4853
利用升级后的巨米波射电望远镜数据，首次探测到过渡型毫秒脉冲星J1227$-$4853的巨脉冲，分析其特性，发现与其他毫秒脉冲星类似，还发现活动增强时巨脉冲率变化及与快速射电暴可能的相似性。
In the present paper a theoretical interpretation of observational characteristics of the pulsar PSR J0540-6919 is suggested. In particular, we provide a theoretical model explaining the presence of two peaks in the radio domain and the brooding of these peaks at higher frequencies. The model also explains the pulse-phase coincidence of emission peaks at different frequencies and shows the physical, 'genetic' connection between the radio remission at frequencies of the order of GHz with gamma-ray emission up to GeV energies.
Einstein's weak equivalence principle (EEP) can be tested through the arrival time delay between photons with different frequencies. Assuming that the arrival time delay is solely caused by the gravitational potential of the Milky Way, we show that a "nano-shot" giant pulse with a time delay between energies corrected for all known effects, e.g. $Δt<0.4~\rm{ns}$, from the Crab pulsar poses a new upper limit on the deviation from EEP, i.e. $Δγ< (0.6-1.8)\times 10^{-15}$. This result provides the hitherto most stringent constraint on the EEP, improving by at least 2 to 3 orders of magnitude from…
We present the results obtained from timing and spectral studies of the accretion powered X-ray pulsar 2S~1417-624 during a giant outburst in 2009 by using {\it Rossi X-ray Timing Explorer (RXTE)} observations. X-ray pulsations were detected in the light curves obtained from all epochs of observations. The pulsar was found to be spinning-up during the outburst. The pulse profiles were observed to be strongly dependent on photon energy and luminosity. A double peaked profile at lower luminosity evolved into a triple peaked profile at the peak of the outburst which is further reverted back to a …
Radio timing observations of the high-magnetic-field pulsar PSR J1718-3718 have shown that it suffered a large glitch with Dnu_g/nu = (33.25 +/- 0.01) x 10^{-6} between 2007 September (MJD 54336) and 2009 January (MJD 54855). This is the largest pulsar glitch ever observed. As is common, there was a small increase in braking torque at the time of the glitch but, unlike all other pulsars, the braking torque has continued to increase over the two years since the glitch. Polarization observations show that the mean pulse profile has about 30% linear polarization with a smooth change of position a…
We present optical photometric and spectroscopic observations of the likely stellar counterpart to the unassociated \emph{Fermi}-Large Area Telescope (LAT) $γ$-ray source 2FGL J0846.0+2820, selected for study based on positional coincidences of optical variables with unassociated LAT sources. Using optical spectroscopy from the SOAR telescope, we have identified a late-G giant in an eccentric ($e$ = 0.06) 8.133 day orbit with an invisible primary. Modeling the spectroscopy and photometry together lead us to infer a heavy neutron star primary of $\sim 2 M_{\odot}$ and a partially stripped giant…
We present a large survey of giant pulses from the Crab Pulsar as observed with the first station of the Long Wavelength Array. Automated methods for detecting giant pulses at low frequencies where scattering becomes prevalent are also explored. More than 1400 pulses were detected across four frequency bands between 20 - 84 MHz over a seven month period beginning in 2013, with additional followup observations in late 2014 and early 2015. A handful of these pulses were detected simultaneously across all four frequency bands. We examine pulse characteristics, including pulse broadening and power…
No apparent correlation was found between giant pulses (GPs) and X-ray photons from the Crab pulsar during 5.4 hours of simultaneous observations with the Green Bank Telescope at 1.5 GHz and Chandra X-Ray Observatory primarily in the energy range 1.5-4.5 keV. During the Crab pulsar periods with GPs the X-ray flux in radio emission phase windows does not change more than by +-10% for main pulse (MP) GPs and +-30% for interpulse (IP) GPs. During giant pulses themselves, the X-ray flux does not change more than by two times for MP GPs and 5 times for IP GPs. All limits quoted are compatible with …
Optical Follow-Up of Two Spider Pulsar Candidates: An Irradiated Redback and a Possible Double Giant Impostor
对两颗蜘蛛脉冲星候选体进行光学后随观测，发现J0846实为双红巨星而非脉冲星，J0935被确认为处于脉冲星状态的红背蜘蛛。
We made a detailed study of the timing and spectral properties of the X-ray pulsar 1A 0535+262 during the recent giant outburst in 2020 November and December. The flux of the pulsar reached a record value of $\sim$12.5 Crab as observed by Swift/BAT (15--50 keV) and the corresponding mass accretion rate was $\sim6.67\times10^{17}$ g s$^{-1}$ near the peak of the outburst. There was a transition from the subcritical to the supercritical accretion regime which allows exploring different properties of the source in the supercritical regime. A q-like feature was detected in the hardness-intensity d…
Radio timing observations of a millisecond pulsar in orbit around the Galactic centre black hole (BH) or a BH at the centre of globular clusters could answer foundational questions in astrophysics and fundamental physics. Pulsar radio astronomy typically employs the post-Keplerian approximation to determine the system parameters. However, in the strong gravitational field around the central BH, higher order relativistic effects may become important. We compare the pulsar timing delays given by the post-Keplerian approximation with those given by a relativistic timing model. We find significant…
The discovery of source states in the X-ray emission of black-hole binaries and neutron-star low-mass X-ray binaries constituted a major step forward in the understanding of the physics of accretion onto compact objects. While there are numerous studies on the correlated timing and spectral variability of these systems, very little work has been done on high-mass X-ray binaries, the third major type of X-ray binaries. The main goal of this work is to investigate whether Be accreting X-ray pulsars display source states and characterise those states through their spectral and timing properties. …
An extreme particle accelerator powered by pulsar PSR J1849-0001
LHAASO发现PSR J1849-0001驱动的脉冲星风云释放极高能伽马射线，其加速效率接近或超过单位，挑战了传统粒子加速理论。
The solution for the electromagnetic tornado in a vacuum gap of a pulsar that could serve as an explanation of the observed circular polarization of giant pulses from pulsars and might also explain the frequency strips observed in giant pulses spectrum is found.
Giant Hall Waves Launched by Superconducting Phase Transition in Pulsars
脉冲星核心超导相变触发地壳磁场非线性霍尔漂移，产生巨型霍尔波，可能破裂地壳、引发星震和旋转突变，并促进磁通排出。
We present statistical analysis of a fluence limited sample of over 1100 giant pulses from the Crab pulsar, with fluence > 130 Jy ms at ~1330 MHz. These were detected in ~260 hours of observation with the National Centre for Radio Astrophysics (NCRA)-15m radio telescope. We find that the pulse energy distribution follows a power law with index $α\approx$-3 at least up to a fluence of ~5 Jy s. The power law index agrees well with that found for lower energy pulses in the range 3-30 Jy ms. The fluence distribution of the Crab pulsar hence appears to follow a single power law over ~3 orders of ma…
Nearby pulsar wind nebulae exhibit complex morphological features: jets, torus, arcs and knots. These structures are well captured and understood in the scope of global magnetohydrodynamic models. However, the origin of knots in the inner radius of the Crab Nebula remains elusive. In this work, we investigate the dynamics of the shock front and downstream flow with a special emphasis on the reconnecting equatorial current sheet. We examine whether giant plasmoids produced in the reconnection process could be good candidates for the knots. To this end, we perform large semi-global three-dimensi…
Expanding on the comment by Lyne et al (2017), that intermittent pulsars tend to congregate near a stripe in the logarithmic period versus period-derivative diagram, representing a small range of polar cap electric potential, as well as the fact (already apparent in their Fig.~7, but not explicitly stated there) that high-fraction nulling pulsars also tend to reside within this and an additional stripe, we make the observation that the two stripes further match the "death lines" for double and single-pole interpulses, associated with nearly orthogonal and aligned rotators respectively. These e…
A wide range of events observed at the giant pulses (high energy density, observed localization of giant pulses (GPs) relative to the average pulse, fine structure of GPs with duration up to some nanoseconds, observed circular polarization of GPs, correlation between the GP phase and the phase of the hard pulsar emission X-ray and gamma) can be explained from the viewpoint that the internal polar gap is a cavity-resonator stimulated by discharges and radiating through the breaks in the magnetosphere. The new results in this field [the electromagnetic (em) waves generation in the gap in the pro…
Eccentric millisecond pulsars (eMSPs) with white dwarf companions exhibit orbital eccentricities orders of magnitude larger than predicted by turbulent convection in the white dwarfs' red giant progenitors. The orbital periods of eMSPs cluster around $P=20-30$ d, remarkably close to the red giant convective eddy turnover time $t_{\rm eddy}$. We propose that the anomalously large eccentricities are resonantly driven by convective flows somehow made coherent when the turnover time matches the tidally locked red giant's spin period, which is also the tidal forcing period. Numerical simulations of…
We have studied the statistical and polarization properties of giant pulses (GPs) emitted by the millisecond pulsar B1937+21, with high sensitivity and time resolution. The observations were made in June 2005 with the 100-m Robert C. Byrd Green Bank Telescope at S-band (2052-2116 MHz) using the Mk5A VLBI recording system, with formal time resolution of 16 ns. The total observing time was about 4.5 hours; the rate of detection of GPs was about 130 per hour at the average longitudes of the main pulse (MPGPs) and 60 per hour at the interpulse (IPGPs). While the average profile shows well-defined …
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