On the PulsarOn the Pulsar



This book serves as a good introduction to The physics of pulsars by explaining the subject matter in simple terms which are understandable to both undergraduate physics students and also the general public.

Author: B. B. Kadomsev

Publisher: World Scientific

ISBN: 9789814289726

Category:

Page: 135

View: 629

This book serves as a good introduction to The physics of pulsars by explaining the subject matter in simple terms which are understandable to both undergraduate physics students and also the general public. On the Pulsar links together ideas about physics, informatics and biology, and contains many original examples, problems and solutions. it starts with simple examples about the regular structures that are possible in strong magnetic fields and The author then suggests that special conditions on the pulsar can result in some forms of self-organization. it will also make a valuable teaching guide.

Decoding the Message of the PulsarsDecoding the Message of the Pulsars



In Decoding the Message of the Pulsars, LaViolette shows that pulsars are distributed in the sky in a nonrandom fashion, often marking key galactic locations, and that their signals are of intelligent origin.

Author: Paul A. LaViolette

Publisher: Inner Traditions / Bear & Co

ISBN: 1591430623

Category:

Page: 224

View: 844

Paul LaViolette's 25 years of research into the precisely timed radio pulses from extraterrestrial sources known as pulsars shows that they are distributed in the sky in a nonrandom fashion, often marking key galactic locations, and that their signals are of intelligent origin, warning about a past galactic core explosion that could recur in the near future.

Rotation Powered Pulsars in the X raysRotation Powered Pulsars in the X rays



The dissertation focuses on the study of rotation-powered pulsars, the primary observational manifestation of neutron stars.

Author: Prakash Arumugasamy

Publisher:

ISBN: OCLC:943064501

Category:

Page:

View: 854

The dissertation focuses on the study of rotation-powered pulsars, the primary observational manifestation of neutron stars. These objects are powerful sources of electromagnetic radiation and relativistic particles whose emission is provided by the loss of pulsar rotational energy. Understanding the evolution of pulsars, which happens over billion year timescales, requires detection and study of pulsars at different stages of evolution. I present detailed X-ray analyses of pulsars at four distinct stages of evolution and compare their emission behavior with that of other pulsars expected to be in similar evolutionary stages. I also show key characteristics of the pulsars that make them unique in their group. I start with a young and energetic pulsar, PSR J2022+3842 (characteristic age approximately 9 kyr, spin-down power = 3E37 erg/s), with powerful non-thermal emission. X-ray timing of the pulsar revealed double-peaked X-ray profile with a period twice the previously established value. Our analysis allowed us to update the pulsar's spin-down power and X-ray efficiency using the correct timing results, which brought the pulsar more in-line with other young X-ray pulsars. I also provide the phase-dependent behavior of the pulsar's non-thermal emission. Pulsars with true ages, often substituted by characteristic age, below ~ 100 kyr are considered young and ones with ages > 1 Myr are considered old, with the 'middle-aged' pulsars in the middle. My next pulsar is a 1.8 Myr old J1836+5925 (spin-down power = 1E34 erg/s), which is perhaps the brightest X-ray source among the oldest pulsars still observable in the gamma-rays. Detailed timing and spectral analyses show strong evidence of an absorption feature (perhaps an electron cyclotron line) in the pulsar's spectrum. Characterizing its thermal emission might have important implications for the neutron star cooling models. Moving another two orders of magnitude up in characteristic age, we have one of the oldest known non-recycled X-ray pulsars, PSR J0108-3430, with characteristic age = 166 Myr and spin-down power = 5.8E30 erg/s. The pulsar's spectrum likely consists of a thermal component, emitted from a hot polar cap, and a non-thermal component, emitted from its magnetosphere. The X-ray pulse profile shows a single, asymmetric peak which could be explained by an axially-asymmetric temperature distribution at the pole or by the non-thermal emission from the outer gap. The three pulsars represent important stages in the evolutionary path that a hypothetical single young pulsar like J2022+3842 might take, as it passes through stages close to gamma-ray emission turn-off (like J1836+5925) and X-ray turn-off (similar to J0108-3430).Pulsars in binaries can follow an alternative path. By accreting matter from their companions they can be 'recycled' to short millisecond periods and emit X-rays and gamma-rays for billions of years. I also present a special class of such recycled pulsars which are believed to be in the process of fatally ablating their companions. I present the X-ray analysis of PSR J1446-4701, a pulsar with spin-down power = 3.6E34 erg/s in a 6.7 hr binary orbit, and PSR J1311-3430, a pulsar with spin-down power = 4.9E34 erg/s, in an extreme 1.6 hr binary orbit. PSR J1446-4701 turned out to be a non-eclipser with possibly low (face-on) orbital inclination, with emission from both the pulsar and the intra-binary shock observable throughout the binary orbit. PSR J1311-3430 is a known eclipser, in which we find hints of spectral variability between pulsar superior and inferior conjunction phases. I also present a comprehensive comparison of the sample of such extremely low-mass binary pulsars. We reveal the true nature of pulsars, slowly and steadily, usually one target at a time, but eventually we expect useful patterns to emerge that improves our understanding of the population of rotation powered pulsars.

Revealing the Most Energetic Light from Pulsars and Their NebulaeRevealing the Most Energetic Light from Pulsars and Their Nebulae



This book reports on the extraordinary observation of TeV gamma rays from the Crab Pulsar, the most energetic light ever detected from this type of object.

Author: David Carreto Fidalgo

Publisher: Springer

ISBN: 9783030241940

Category:

Page: 208

View: 533

This book reports on the extraordinary observation of TeV gamma rays from the Crab Pulsar, the most energetic light ever detected from this type of object. It presents detailed information on the painstaking analysis of the unprecedentedly large dataset from the MAGIC telescopes, and comprehensively discusses the implications of pulsed TeV gamma rays for state-of-the-art pulsar emission models. Using these results, the book subsequently explores new testing methodologies for Lorentz Invariance Violation, in terms of a wavelength-dependent speed of light. The book also covers an updated search for Very-High-Energy (VHE), >100 GeV, emissions from millisecond pulsars using the Large Area Telescope on board the Fermi satellite, as well as a study on the promising Pulsar Wind Nebula candidate PSR J0631. The observation of VHE gamma rays is essential to studying the non-thermal sources of radiation in our Universe. Rotating neutron stars, also known as pulsars, are an extreme source class known to emit VHE gamma rays. However, to date only two pulsars have been detected with emissions above 100 GeV, and our understanding of their emission mechanism is still lacking.

On the PulsarOn the Pulsar



“Now let us try to understand what occurs outside the pulsar. A pulsar is like a quickly rotating magnetic dipole. Let us assume for simplicity that the ...

Author: B. B. Kadomt︠s︡ev

Publisher: World Scientific

ISBN: 9789814289740

Category:

Page: 148

View: 591

This book serves as a good introduction to the physics of pulsars by explaining the subject matter in simple terms which are understandable to both undergraduate physics students and also the general public. On the Pulsar links together ideas about physics, informatics and biology, and contains many original examples, problems and solutions. It starts with simple examples about the regular structures that are possible in strong magnetic fields and the author then suggests that special conditions on the pulsar can result in some forms of self-organization. It will also make a valuable teaching guide. Sample Chapter(s). Foreword (35 KB). Chapter 1: Unexpected Encounter (39 KB). Contents: Unexpected Encounter; What is a Pulsar?; Mischievous Ball; Misha and Sasha; Playing Billiards; Stubborn Fountains; In the Country of Anisotropic Masses; Matter in a Superstrong Magnetic Field; Neutron Star; Physics of the Pulsar; Non-linearity and Self-organization; On the Pulsar. Readership: Students and general public interested in astrophysics and informatics.

Neutron Stars and PulsarsNeutron Stars and Pulsars



This book will be a valuable source of information for these groups. Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation.

Author: Werner Becker

Publisher: Springer Science & Business Media

ISBN: 9783540769651

Category:

Page: 697

View: 232

Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only reviews the progress made since the early days of pulsar astronomy, but especially focuses on questions such as: "What have we learned about the subject and how did we learn it?", "What are the most important open questions in this area?" and "What new tools, telescopes, observations, and calculations are needed to answer these questions?". All authors who have contributed to this book have devoted a significant part of their scientific careers to exploring the nature of neutron stars and understanding pulsars. Everyone has paid special attention to writing educational comprehensive review articles with the needs of beginners, students and young scientists as potential readers in mind. This book will be a valuable source of information for these groups.

Radio Pulsars An Astrophysical Key to Unlock the Secrets of the UniverseRadio Pulsars An Astrophysical Key to Unlock the Secrets of the Universe



This book covers a broad range of radio pulsar-related topics, which were presented and discussed at the conference held in Chia (Sardinia, Italy) in October 2010.

Author: Marta Burgay

Publisher: American Inst. of Physics

ISBN: 0735409153

Category:

Page: 390

View: 874

This book covers a broad range of radio pulsar-related topics, which were presented and discussed at the conference held in Chia (Sardinia, Italy) in October 2010. At that time, the first unexpected discoveries of some new large scale pulsar surveys began to appear, while the recent strong efforts of the pulsar scientific community in the fields of timing and of the "timing arrays" led to many exciting results. Moreover, fall 2010 turned out to be the right time to elaborate on the first theoretical consequences from the unprecedented database of gamma-ray data collected by Fermi and Agile satellites. As stated by Jocelyn Bell - whose 45 year career were celebrated during the conference - the radio pulsar field "keeps re- inventing itself [....] and this pattern has continued at this meeting with once again intriguing, fascinating results being presented."

Recycled PulsarsRecycled Pulsars



Several of these recycled pulsars are particularly interesting: PSR J1528-3146 is in a circular orbit with a companion of at least 0.94 solar masses; it is a member of the recently recognized class of intermediate mass binary pulsar (IMBP) ...

Author: Bryan Anthony Jacoby

Publisher: Universal-Publishers

ISBN: 9781581123937

Category:

Page: 116

View: 927

We present the results of a large-area survey for millisecond pulsars (MSPs) at moderately high galactic latitudes with the 64 m Parkes radio telescope, along with follow-up timing and optical studies of the newly-discovered pulsars and several others. Major results include the first precise measurement of the mass of a fully recycled pulsar and measurement of orbital period decay in a double neutron star binary system allowing a test of general relativity along with improved measurements of the neutron star masses. In a survey of approx. 4,150 square degrees, we discovered 26 previously unknown pulsars, including 7 "recycled" millisecond or binary pulsars. Several of these recycled pulsars are particularly interesting: PSR J1528-3146 is in a circular orbit with a companion of at least 0.94 solar masses; it is a member of the recently recognized class of intermediate mass binary pulsar (IMBP) systems with massive white dwarf companions. We have detected optical counterparts for this and one other IMBP system; taken together with optical detections and non-detections of several similar systems, our results indicate that the characteristic age consistently overestimates the time since the end of mass accretion in these recycled systems. This result implies that the pulsar spin period at the end of the accretion phase is not dramatically shorter than the observed period as is generally assumed. PSR J1600-3053 is among the best high-precision timing pulsars known and should be very useful as part of an ensemble of pulsars used to detect very low frequency gravitational waves. PSR J1738+0333 has an optical counterpart which, although not yet well-studied, has already allowed a preliminary measurement of the system's mass ratio. The most significant discovery of this survey is PSR J1909-3744, a 2.95 ms pulsar in an extremely circular 1.5 d orbit with a low-mass white dwarf companion. Though this system is a fairly typical low-mass binary pulsar (LMBP) system, it has several exceptional qualities: an extremely narrow pulse profile and stable rotation have enabled the most precise long-term timing ever reported, and a nearly edge-on orbit gives rise to a strong Shapiro delay signature in the pulse timing data which has allowed the most precise measurement of the mass of a millisecond pulsar: 1.438 ± 0.024 solar masses. Our accurate parallax distance measurement, d = 1.14 +0.08 / -0.07 kpc, combined with the mass of the optically-detected companion, 0.2038 ± 0.022 solar masses, will provide an important calibration for white dwarf models relevant to other LMBP companions. We have measured the decay of the binary period of the double neutron star system B2127+11C in the globular cluster M15. This has allowed an improved measurement of the mass of the pulsar, 1.3584 ± 0.0097 solar masses, and companion, 1.3544 ± 0.0097 solar masses, as well as a test of general relativity at the 3% level. We find that the proper motions of this pulsar as well as B2127+11A and B2127+11B are consistent with each other and with one published measurement of the cluster proper motion. We have discovered three binary millisecond pulsars in the globular cluster M62 using the 100-m Green Bank Telescope (GBT). These pulsars are the first objects discovered with the GBT. We briefly describe a wide-bandwidth coherent dedispersion backend used for some of the high precision pulsar timing observations presented here.

On the PulsarOn the Pulsar



This book serves as a good introduction to the physics of pulsars by explaining the subject matter in simple terms which are understandable to both undergraduate physics students and also the general public.

Author:

Publisher:

ISBN: 9789814466301

Category:

Page:

View: 290

Physics of the Pulsar MagnetospherePhysics of the Pulsar Magnetosphere



Pulsars with interpulse - AP/P Pulsar P(s) P-1s (deg) Hall." z (deg) Reference" 0531 +21 0.033 421 216 0.69 86 1 0823+26 0.531 1.7 180 0.005 84 1 0826–34 ...

Author: V. S. Beskin

Publisher: Cambridge University Press

ISBN: 0521417465

Category:

Page: 408

View: 967

This book presents the theory of the electrodynamic phenomena that occur in the magnetosphere of a pulsar. It also provides a clear picture of the formation and evolution of neutron stars. The authors address the basic physical processes of electron-positron plasma production, the generation of electric fields and currents, and the emission of radio waves and gamma rays. The book also reviews the current observational data, and devotes a complete chapter to a detailed comparison of this data with accepted theory and with some recent theoretical predictions. Tables containing the values of the physical parameters of all observed radio pulsars are also provided.

Pulsar Radio Emission Modulation in Relation to Rotational InstabilityPulsar Radio Emission Modulation in Relation to Rotational Instability



In this work, we have studied three extreme nulling pulsars to help determine how these objects can be best classified, and what the most viable processes responsible for their behaviour could be.

Author: Neil James Young

Publisher:

ISBN: OCLC:806197084

Category:

Page: 227

View: 137

The magnetospheric conditions responsible for radio emission in pulsars are still not clearly understood. Through studying the modulation of this emission, in relation to the rotational properties of these stars, the observer can obtain insight into the mechanism which governs the radio emission in pulsars, as well as their magnetospheric environments. Nulling pulsars are instrumental in this study due to their meta-stable configurations, which result in abrupt cessation or re-activation of their radio emission. As the observed modulation timescales in these sources vary from seconds to years, several theories have been proposed to explain their behaviour. However, no consensus has been reached on what triggers their magnetospheric reconfigurations, nor whether they are all governed by the same processes. In this work, we have studied three extreme nulling pulsars to help determine how these objects can be best classified, and what the most viable processes responsible for their behaviour could be. Using approximately 13 years of high-cadence observations, we confirm that the prototype 'intermittent' pulsar, PSR B1931+24, has a variable spin-down rate which is correlated with the presence (absence) of radio emission. The spin-down rates of the pulsar, attributed to the radio-on and -off emission phases, do not exhibit any evidence for time evolution and, as such, retain a constant difference of ~50 % throughout the 13-year data-set. We find that the radio-on and -off emission phases last approximately 8 days and 22 days on average respectively. They are also found to repeat quasi-periodically, over an average timescale of 36 days. We find no evidence for any interruptions to a given emission phase, that is the pulsar appears to switch between emission phases over long timescales (~days) only. Using our unprecedented data span, we find the object has an overall nulling fraction of 74 ± 6 %. We use an unparallelled 153-day set of observations to show that the pulsar B0823+26 exhibits a bimodal distribution of nulling timescales, that is short nulls (~1-3 pulse periods) and long nulls (~100-10 000 pulse periods) that are not periodic in nature. Remarkably, the longest nulls observed in PSR B0823+26 can be as extreme as those found in rotating radio transients (RRATs). The pulsar is shown to undergo pre-ignition periods of emission bursts and nulls before transitioning to a reasonably steady radio-on phase. Through characterising the emission variability of the source in the radio-on phases, we find that the post-cursor emission component exhibits a remarkable degree of variability. We do not obtain any direct evidence for spin-down rate variation in this pulsar, but we do place an upper limit of d"6 % on any change. We also investigate the radio emission characteristics of PSR J1107-5907, and find that it exhibits a wide range of nulling timescales (i.e. seconds to many hours). Coupled with its highly irregular bright emission, these nulling properties suggest a strong link between this object and RRAT-like sources. Although the pulsar undergoes both nulls and dramatic pulse shape changes, no evidence for spin-down rate variation is obtained. The nulling properties of the sources studied suggest a close relationship between conventional nulling pulsars, RRATs and intermittent pulsars. We find that the existing characterisation of the different types of nulling pulsars, based on their initial detection properties, is unsuitable. We also predict that, in addition to those yet undetected, a significant number of nulling objects are located in the existing known pulsar population, but have not yet been fully characterised.

X ray Timing of Young PulsarsX ray Timing of Young Pulsars



"Pulsars are the rotating compact remnants of exploded massive stars.

Author: Robert Archibald

Publisher:

ISBN: OCLC:1013747555

Category:

Page:

View: 136

"Pulsars are the rotating compact remnants of exploded massive stars. The region surrounding the neutron star, known as the magnetosphere, has properties which are determined by the magnetic ield of the star. In this thesis, I present several observational results involving rotation-powered radio pulsars and magnetars which indicate that pulsar magnetospheres have a more complex structure than a simple dipole, and that the magnetosphere can have a strong efect on all the observed properties of neutron stars. One way to probe the pulsar magnetosphere is through the measurement of braking indices. A braking index quantifies the dependence of the torque on the spin frequency. In Chapter 4 I present a long-term timing study of the rotation-powered pulsar PSR J1846−0258, where we show that the change in braking index reported in this source is long-lived. The most plausible explanation for this changed braking index appears to be due to a change in magnetospheric configuration. In Chapter 5, I present the measurement of a new braking index for the rotation-powered pulsar PSR J1640−4631 of n= 3.15 ± 0.03 - the first measured braking index higher than the canonical three of a magnetic dipole. This result demonstratesthat other physical mechanisms, such as mass or magnetic quadrupole moments most likely need to be taken into account to describe pulsar spin-down & energetics.Another way to probe the magnetospheres of pulsars is by studying the extreme variability seen in the magnetar class. In Chapter 6 I present two years of flux and spin evolution monitoring of the magnetar 1E 1048.1−5937 following an outburst. By comparing to previous outbursts from the source, we show that this pattern of behaviour repeats itself with a quasi-period of ∼1800 days. This behaviour, when compared to similar less extreme events seen in rotation-powered pulsars, appears to implicate processes in the stellar magnetosphere. In Chapter 7, I present the results of monitoring the magnetar 4U 0142+61 over two outbursts, including one with a net spin-down timing event, and compare this timing event to previous such events in other pulsars with high magnetic fields anddiscuss net spin-down glitches now seen in several young, high-B pulsars. The observations that these spin-down events occur in only high-B sources strongly implicates the influence of a large magnetic field in spin-down events and, coupled with the radiatively loud nature of the plurality of spin-down events, suggests an origin in the magnetosphere of the star. In Chapter 8 I present observations of a magnetar-like outburst from the high-magnetic-field pulsar PSR J1119−6127, providing an unambiguous connection between the radio pulsar and magnetar populations.Finally, in Chapter 9, I put these new results in context with recent advances in neutron-star astrophysics, and speculate on avenues for future advancement in the field." --

Disentangling X Ray Emission Processes in Vela Like PulsarsDisentangling X Ray Emission Processes in Vela Like Pulsars



The associated supernova remnant is not detected directly, most likely being too faint to be seen in existing X-ray and radio observations. Gaensler, Bryan and Mushotzky, Richard (Technical Monitor) Goddard Space Flight Center

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

ISBN: 1721603131

Category:

Page: 28

View: 484

We present a deep observation with the X-Ray Multimirror Mission of PSR B1823-13, a young pulsar with similar properties to the Vela pulsar. We detect two components to the X-ray emission associated with PSR B1823-13: an elongated core of extent 30 min immediately surrounding the pulsar embedded in a fainter, diffuse component of emission 5 sec in extent, seen only on the southern side of the pulsar. The pulsar itself is not detected, either as a point source or through its pulsations. Both components of the X-ray emission are well fitted by a power-law spectrum, with photon index Gamma approx. 1.6 and X-ray luminosity (0.5-10 keV) L(sub X) approx. 9 x 10(exp 32) ergs/s for the core and Gamma approx. 2.3 and L(sub X) approx. 3 x 10(exp 33) ergs/s for the diffuse emission, for a distance of 4 kpc. We interpret both components of emission as corresponding to a pulsar wind nebula, which we designate G18.0-0.7. We argue that the core region represents the wind termination shock of this nebula, while the diffuse component indicates the shocked downstream wind. We propose that the asymmetric morphology of the diffuse emission with respect to the pulsar is the result of a reverse shock from an associated supernova remnant, which has compressed and distorted the pulsar-powered nebula. Such an interaction might be typical for pulsars at this stage in their evolution. The associated supernova remnant is not detected directly, most likely being too faint to be seen in existing X-ray and radio observations. Gaensler, Bryan and Mushotzky, Richard (Technical Monitor) Goddard Space Flight Center

Pulsar Astrophysics IAU S337 Pulsar Astrophysics IAU S337



Ever since their discovery in 1967, pulsars and neutron stars have provided an unprecedented opportunity to study the extremes of physics.

Author: Patrick Weltevrede

Publisher: Cambridge University Press

ISBN: 1107192536

Category:

Page: 500

View: 349

Ever since their discovery in 1967, pulsars and neutron stars have provided an unprecedented opportunity to study the extremes of physics. This started with the very rapid identification of pulsars as rotating neutron stars with extremely strong magnetic fields and, selecting just a few highlights from the following decades, was followed by the discovery of the Hulse-Taylor binary, millisecond pulsars, the first pulsars in globular clusters, the pulsar planets and the double pulsar. In the last decade alone, we have made some amazing discoveries and observations with an impact across all areas of astronomy. With these proceedings of IAU Symposium 337, the 50th anniversary of the discovery of pulsars is celebrated by reflecting on what we have learned from these remarkable physical laboratories and by casting our eyes forward to the exciting opportunities they will provide for physical and astrophysical studies in the coming decades.

Gamma Ray Emissions from Pulsar BinariesGamma Ray Emissions from Pulsar Binaries



This dissertation, "Gamma-ray Emissions From Pulsar Binaries" by Chun-kwan, Leung, 梁晉堃, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong ...

Author: Chun-Kwan Leung

Publisher: Open Dissertation Press

ISBN: 1361348550

Category:

Page:

View: 158

This dissertation, "Gamma-ray Emissions From Pulsar Binaries" by Chun-kwan, Leung, 梁晉堃, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: The launch of the Fermi Gamma-ray Space Telescope marked a new era in observing gamma-rays from astrophysical sources. Fermi's high sensitivity in the 0.1-300GeV energy range opens an important window in the observation of the gamma-ray emissions from pulsar binaries, which emit most of their radiation energy in the gamma-ray range. We can now observe the gamma-ray emissions from pulsar binaries at an unprecedented accuracy, and investigate their origin in detail. In this thesis, we present the studies on two systems of pulsar binary of two distinct classes. The gamma-ray emissions from the high-mass gamma-ray binary LS 5039 were studied using the latest data from Fermi. The emission is modulated according to the 3.9 hr orbital period of the system. The results can be explained by the contribution of three components: the pulsar magnetospheric emission, the pulsar wind emission and the emissions from the shock formed from the interaction between the pulsar wind and companion's stellar wind. The results were compared with observed data from Fermi and also in X-ray and TeV. In addition, the emissions from the millisecond pulsar PSR J1023+0038 and its low mass binary companion were also studied. This system recently went through a transition from the rotation-powered state to the accretion state, after going the opposite way in 2007. This state transition, discovered through the disappearance of radio pulsation, was accompanied by the brightening in GeV, X-ray and UV fluxes. A detailed Fermi observation was performed, supplemented by multi-wavelength observations. It was found that the emission from this system can also be described by the emissions from the pulsar magnetosphere, the pulsar wind and its shock. These two systems, although of distinct classes of pulsar binaries, provide complementary cases for the study of high-energy radiation processes in pulsar binaries. DOI: 10.5353/th_b5317064 Subjects: Gamma ray astronomy Pulsars

Gravitational Wave Detection and Data Analysis for Pulsar Timing ArraysGravitational Wave Detection and Data Analysis for Pulsar Timing Arrays



In chapter 3, the gravitational-wave memory effect is described. This is one of the first descriptions of this interesting effect in relation with pulsar timing, which may become observable in future Pulsar Timing Array projects.

Author: Rutger van Haasteren

Publisher: Springer Science & Business Media

ISBN: 9783642395994

Category:

Page: 139

View: 936

Pulsar timing is a promising method for detecting gravitational waves in the nano-Hertz band. In his prize winning Ph.D. thesis Rutger van Haasteren deals with how one takes thousands of seemingly random timing residuals which are measured by pulsar observers, and extracts information about the presence and character of the gravitational waves in the nano-Hertz band that are washing over our Galaxy. The author presents a sophisticated mathematical algorithm that deals with this issue. His algorithm is probably the most well-developed of those that are currently in use in the Pulsar Timing Array community. In chapter 3, the gravitational-wave memory effect is described. This is one of the first descriptions of this interesting effect in relation with pulsar timing, which may become observable in future Pulsar Timing Array projects. The last part of the work is dedicated to an effort to combine the European pulsar timing data sets in order to search for gravitational waves. This study has placed the most stringent limit to date on the intensity of gravitational waves that are produced by pairs of supermassive black holes dancing around each other in distant galaxies, as well as those that may be produced by vibrating cosmic strings. Rutger van Haasteren has won the 2011 GWIC Thesis Prize of the Gravitational Wave International Community for his innovative work in various directions of the search for gravitational waves by pulsar timing. The work is presented in this Ph.D. thesis.

Trends in Pulsar ResearchTrends in Pulsar Research



Pulsars are stars, a significant part of whose observed energy output is not continuous but is emitted as distinct flashes or pulses of electromagnetic radiation.

Author: John A. Lowry

Publisher: Nova Publishers

ISBN: 1594545677

Category:

Page: 211

View: 834

Pulsars are stars, a significant part of whose observed energy output is not continuous but is emitted as distinct flashes or pulses of electromagnetic radiation. Many pulsars also emit some radiation weakly and constantly, forming a background for the more intensive pulses. Three distinct classes of pulsars are presently known to astronomers, according to the source of energy that powers the radiation: Rotation-powered pulsars, where the loss of rotational energy of the star powers the radiation X-ray pulsars, where the gravitational potential energy of accreted matter is the energy source, and Magnetars, where the decay of an extremely strong magnetic field powers the radiation. Although all three classes of objects are neutron stars, their observable behaviour and the underlying physics are quite different. There are, however, connections. For example, X-ray pulsars are probably old rotation-powered pulsars that have already lost most of their energy, and have only become visible again after their binary companions expanded and began transferring matter on to the neutron star. The process of accretion can in turn transfer enough angular momentum to the neutron star to "recycle" it as a rotation-powered millisecond pulsar.

Pulsar AstronomyPulsar Astronomy



radiation which may be detectable over the whole spectrum from radio to gamma-rays as a pulsar wind nebula, or PWN. The particle energies may be high enough ...

Author: Andrew Lyne

Publisher: Cambridge University Press

ISBN: 9781107010147

Category:

Page: 345

View: 575

Now in its fourth edition, Pulsar Astronomy provides a thoroughly revised and updated introduction to the field of pulsar astronomy.

Phase Resolved Analysis of Pulsar PSR J2032 2 4126Phase Resolved Analysis of Pulsar PSR J2032 2 4126



Abstract : Pulsars are an extremely dense and highly magnetized rotating neutron stars. Their periodic rotation produces pulsed emissions and this periodicity makes them a very useful tool in various studies.

Author:

Publisher:

ISBN: OCLC:1156966223

Category:

Page:

View: 299

Abstract : Pulsars are an extremely dense and highly magnetized rotating neutron stars. Their periodic rotation produces pulsed emissions and this periodicity makes them a very useful tool in various studies. Hundreds of Ɣ-ray pulsars have been discovered with the increasing number of telescopes and observing facilities. The Fermi Large Area Telescope (LAT) has been taking data from the direction of the Cygnus region and has reported multiple pulsars in the region. One of the brightest pulsars reported is PSR J2032.2+4126, which has been detected at both radio and gamma ray energies. Emission from these bright pulsars outshine the gamma ray sources in their vicinity. Hence, in addition to understanding the pulsar, estimating the on-pulse and off-pulse periods of the pulsar can be crucial to understand and analyze the fainter sources in the nearby region. PSR J2032.2+4126 lies directly on top of the Cygnus cocoon, thus this analysis will be used to understand the background in the extended emission analysis from the cocoon region.