ArticlePDF Available

Observation of a Rapidly Pulsating Radio Source

Authors:

Abstract

Unusual signals from pulsating radio sources have been recorded at the Mullard Radio Astronomy Observatory. The radiation seems to come from local objects within the galaxy, and may be associated with oscillations of white dwarf or neutron stars.
... Landau argued that the gravitational binding energy of the core of the star would be sufficient to drive this transformation of matter to 'neutron matter'. More than thirty years elapsed before neutron stars were eventually found by Jocelyn Bell (Hewish et al. 1968). The discovery of pulsars in the Crab Nebula (Staelin and Reifenstein 1968) and in the Vela supernova remnant (Large et al. 1968) confirmed their association with the supernova phenomenon. ...
... In the paper announcing the discovery of pulsars, Hewish et al. (1968) tentatively identified them as either white dwarfs or neutron stars. With the discovery of rapidly spinning pulsars in the Crab and Vela supernova remnants, and the subsequent observational evidence of the lengthening of their periods (Richards and Comella 1969;, it became clear that pulsars must be rotating neutron stars endowed with strong magnetic fields. ...
Article
Full-text available
The first-born neutron star in a binary system will function as a pulsar for a few million years, and then die a natural death as its period lengthens. During mass transfer from the companion star, the dead pulsar will be resurrected from its graveyard. In its reincarnation, the recycled pulsar will have a short rotation period and a much smaller magnetic field than at birth. Although this idea is more than forty years old, with the coming of age of gamma-ray astronomy and the detection of gravitational waves, recycled pulsars have assumed contemporary importance. This article is intended to be a review of the recycling scenario – a history of the seminal ideas and the underlying physics.
... In the 1930s, stellar evolution theories predicted that neutron stars (NSs) could form when a massive star exhausts its fuel and undergoes gravitational collapse (Baade & Zwicky 1934). Many years later, the existence of NSs was confirmed by the discovery of radio pulsars in August 1967 (Hewish et al. 1968). NSs can be powered either by rotational kinetic energy, magnetic energy, or accretion, and they manifest in various ways. ...
Preprint
Full-text available
To date, over 4,000 pulsars have been detected. In this study, we identify 231 X-ray counterparts of {\it ATNF} pulsars by performing a spatial cross-match across the {\it Chandra}, {\it XMM-Newton} observational catalogs. This dataset represents the largest sample of X-ray counterparts ever compiled, including 98 normal pulsars (NPs) and 133 millisecond pulsars (MSPs). Based on this significantly expanded sample, we re-establish the correlation between X-ray luminosity and spin-down power, given by LXE˙0.85±0.05L_{\rm X} \propto \dot{E}^{0.85\pm0.05} across the whole X-ray band. The strong correlation is also observed in hard X-ray band, while in soft X-ray band there is no significant correlation. Furthermore, LXL_{\rm X} shows a strong correlation with spin period and characteristic age for NPs. For the first time, we observe a strongly positive correlation between LXL_{\rm X} and the light cylinder magnetic field (BlcB_{\rm lc}) for MSPs, with both NPs and MSPs following the relationship LXBlc1.14L_{\rm X} \propto B_{\rm lc}^{1.14}, consistent with the outer-gap model of pulsars that explains the mechanism of X-ray emission. Additionally, we investigate potential X-ray counterparts for GPPS pulsars, finding a lower likelihood of detection compared to {\it ATNF} pulsars.
... Additionally, they are now frequently referred to as pulsars. The pulsar signal was reported by Hewish et al. [1], who also provided information on the signal's rang, frequency, speed and other crucial parameters. ...
Article
Full-text available
This research focuses on the evolution of the universe and observes pulsars using modified gravitational theory. We computed the Einstein field equations for an anisotropic spherical structure with f ( R ) gravity. Furthermore, our density–pressure relationship is defined using the well-known van der Waals equation of state (VdW EoS). Graphs are used to investigate the behavior of physical parameters, and energy conditions are used to demonstrate the physical continuity of dense stars. Plotting the adiabatic index shows the model’s stability. The resulting figures of physical parameters confirm the model’s practical and conceptual feasibility. Under the effect of f ( R ) gravity, our work demonstrates regularity, viability and stability, supporting the presence of heavy pulsars such as PSR J0348+0432 J 0348 + 0432 , PSR J0740+6620 J 0740 + 6620 and PSR J0030+0451 J 0030 + 0451 .
... Since the discovery of the first pulsar [1], about 3700 pulsars have been discovered. (according to version 2.5.1 of the ATNF Catalog [2], available here: www.atnf.csiro.au/ ...
Article
Full-text available
Utilizing the databases from the European Pulsar Network (EPN), the Australia Telescope National Facility (ATNF), and published literature data, a geometric method was used to investigate the multifrequency emission altitude of 104 pulsars. We found that the evolution of emission altitudes with frequency for the majority of pulsars can be fitted using a power-law function with a normalization constant. In this work, it is found that the frequency evolution of pulsar emission altitude can be divided into three groups according to their different frequency dependencies of emission altitude (emission altitude decreases with frequency (Group A, η≤−0.1), keeps relatively constant with frequency (Group B, −0.1<η≤0.1), and increases with frequency (Group C, η≥0.1)), where η is the emission altitude variation rate. We also computed the emission altitudes across multiple frequency bands for these pulsars, thereby estimating the approximate range of the pulsar emission regions. We found that most pulsar emissions occur at altitudes of tens to hundreds of kilometers above the polar cap, with differences in emission altitude between the three groups becoming more clear at lower frequencies.
... Pulsars were first discovered in 1967 by Jocelyn Bell Burnell and Antony Hewish, who detected radio-wave pulses with rapid regularity from an unknown source (Hewish et al., 1979). Just one year later, Thomas Gold proposed that pulsars are rapidly rotating, highly magnetized neutron stars that emit radio waves from their magnetic poles. ...
Preprint
Full-text available
The X-ray spectra of isolated neutron stars (INSs) typically include a thermal component, that comes from the cooling surface, and a non-thermal component, produced by highly-relativistic particles accelerated in the stellar magnetosphere. Hot spots from returning currents can also be detected. Middle-aged pulsars exhibit a mixture of these components, but other flavours of INSs, that show a large variety of physical parameters (such as spin period, magnetic field and age) emit only thermal X-rays. Typically, these stars are detected either in large serendipitous datasets from pointed X-ray observations or from searches in the data of all-sky surveys. The connection between these thermally-emitting INSs, the ordinary pulsars, and the new emergent class of pulsars characterized by a long period, that do not show X-ray emission despite their high magnetic field, is one of the current challenges in the study of neutron stars. In this contribution I will review the latest results on several objects belonging to various INS classes, such as the XDINS RX J1308.6+2127, the enigmatic Calvera, the long period PSR J0250+5854 and the new thermal INS candidates, obtained with the X-ray observatories XMM-Newton, NICER and eROSITA.
Article
Full-text available
We present solutions for deformed compact astrophysical objects. We begin by presenting the derivation of the Tolman-Oppenheimer-Volkoff equations from a parameterized metric that takes into account the deformation of the star expressed in terms of a parameter D\mathcal {D}, which is the ratio between polar and equatorial radii. The stellar structure is solved using the GM1 and MIT bag model equations of state, and the “deformed” Tolman-Oppenheimer-Volkoff equation is numerically integrated for different values of D\mathcal {D}. To simplify the analysis, the dimensionality of the problem is reduced to a single radial component, leveraging a direct relationship between D\mathcal {D} and the polar and equatorial directions. This approach allows us to demonstrate the influence of deformation in the star’s mass in a consistent manner. We show that larger values of D>1\mathcal {D}>1, describing prolate objects, yield smaller values of mass and radius, while for smaller values of D<1\mathcal {D}<1, describing oblate objects, larger values for mass and radius are attained. We also show that from the confrontation of our model theoretical predictions with recent observational data on pulsars, it is possible to constrain the values of the parameter D\mathcal {D}. Remarkably, the solutions for the two distinct equations of state, when compared to such observational data, yield the same constraints on the deformation parameter.
Article
The search for long period transients with periods (P) from 2 to 90 s was carried out in daily observations conducted in a area 6300 sq. deg.. The data was obtained on a Large Phased Array (LPA) at a frequency of 111 MHz. Periodograms calculated using the Fast Folding Algorithm (FFA) were used for the search. To increase the sensitivity, the periodograms obtained in different observation sessions were added. Of the 14 known pulsars that entered the study area, having periods P 2 c and dispersion measures (DM) less than 200 pc/cm3, 9 were detected. Two new pulsars were found. The average profiles of pulsars are obtained and estimates of their flux density are given. The discovered pulsar J1951+28, with a period of P = 7.3342 s and DM = 3.5 pc/cm3, turned out to be one of the closest pulsars to the Sun. The absence of new long period transients (pulsars or white dwarf) with periods of tens of seconds with the achieved sensitivity of searching for 1 mJy outside the galactic plane indicates a low probability of the existence of pulsars of neutron stars with extremely long periods. Most likely, the recently found sources of periodic radiation with periods from a minute to tens of minutes are white dwarfs pulsars.
Article
Full-text available
Pulsars are a type of fast-rotating magnetized neutron star that emits beamed multi-wavelength electromagnetic radiation [...]
Article
Determining accurate pulsar timing model parameters is essential for establishing TT(PT), a realization of Terrestrial Time(TT) based on a pulsar time-scale(PT). This study discusses the impact of different data spans on the accuracy of pulsar timing model parameters when determining pulsar timing model parameters. Using observations of PSR J0437-4715, J1909-3744, J1713+0747, and J1744-1134 from the second data release of the International Pulsar Timing Array (IPTA II, Version A), we compare the accuracy of the timing model parameters determined by these observations with different data spans. The results show for PSR J0437-4715, J1713+0747, and J1909-3744, the amplitude fluctuations of rotational frequency remain within 101510^{-15}, 101410^{-14}, and 101410^{-14} Hz, respectively, when the data spans for determining pulsar timing model parameters exceed 13, 14, and 6 years. Additionally, the one-year accuracy of TT(PT) is crucial for its application in timekeeping. By comparing the frequency deviations of TT(PT) relative to TT(BIPM) under both ideal (krk_{r}) and actual (kpk_{p}) conditions across different data spans, we find that when the data span reaches the duration above, the accuracy of TT(PT) surpasses that of TT(TAI) under ideal conditions, slightly inferior under actual conditions. This suggests with improved observational technologies, the accuracy of TT(PT) can be further enhanced.
Article
WITH the discovery of X-ray sources in the sky1,2, speculation has arisen that they might be associated with neutron or hyperon stars formed during the internal collapse which triggers off supernova explosions (probably of type I). Rates of cooling of neutron star models have been calculated by Morton3, Chiu and Salpeter4,5, and Tsuruta6. It appears (J. Bahcall, personal communication) that the importance of the early cooling by emission of neutrinos from the ‘Urca’ process has been underestimated in the foregoing investigations. With rough allowance for this effect, the calculations of Miss Tsuruta indicate that a neutron star will rapidly cool to 3 or 4 × 106 °K, but that after 105 years its surface temperature will still be about 2 × 106 °K.
Article
Solar cosmic rays, discussing flare association, solar particle acceleration, recurrence and low energy solar particle events