We report the discovery of burst oscillations from the intermittent accretion-powered millisecond pulsar (AMP) HETE J1900.1-2455, with a frequency ~1 Hz below the known spin frequency. The burst oscillation properties are far more similar to those of the non-AMPs and Aql X-1 (an intermittent AMP with a far lower duty cycle), than those ...
NASA Astrophysics Data System (ADS)
We have shown previously that many of the properties of persistent accretion-powered millisecond pulsars can be understood if their X-ray emitting areas are near their spin axes and move as the accretion rate and structure of the inner disk vary. Here, we show that this 'nearly aligned moving spot model' may also ...
Energy Citations Database
... is one of the smallest telescopes used for millisecond pulsar observations, we succeeded in detecting several millisecond pulsars by using our new ...
DTIC Science & Technology
... Abstract : Millisecond pulsars attract attentions as a future reference clock in ... system to measure the pulse timing of millisecond pulsar precisely, and ...
We investigate further a model of the accreting millisecond X-ray pulsars we proposed earlier. In this model, the X-ray-emitting regions of these pulsars are near their spin axes but move. This is to be expected if the magnetic poles of these stars are close to their spin axes, so that accreting gas is channeled there. As the accretion ...
The heating associated with the deposition of ?-rays in an accretion disk is proposed as a mechanism to facilitate the transformation of a low-mass X-ray binary to the radio millisecond pulsar (MSP) phase. The ?-ray emission produced in the outer gap accelerator in the pulsar magnetosphere likely irradiates the surrounding disk, ...
We report on a Chandra/ACIS-S observation of the eclipsing accretion-powered millisecond pulsar SWIFT J1749.4-2807, which has recently been reported in a fading outburst during 2010 April 11-21 (ATels #2548, #2561, #2565, #2569, #2576, #2579). Our 1080 s observation was made on April 25 (12:25 TT). Using the pulsar ...
We present X-ray observations of the transient accretion-powered millisecond pulsar IGR J00291+5934 during quiescence. IGR J00291+5934 is the first source among accretion-powered millisecond pulsars to show signs of a thermal component in its quiescent spectrum. Fitting ...
RXTE observations have shown that weak-field neutron stars in low-mass X-ray binary systems (LMXBs) produce three distinct types of millisecond X-ray oscillations. These are generated directly or indirectly by the star's magnetic field and rotation and can therefore be used to determine the spin rates and estimate the magnetic fields of these stars. Periodic ...
... related to the lifetime of the pulsar, the new millisecond pulsar J1713 + 0747 ... Over the fast five years, dozens of new millisecond pulsars have been ...
... 473 Page 5. and use it to observe other millisecond pulsars for contributing to the construction of pulsar time scale. ACKNOWLEDGMENTS ...
The only known accretion-powered millisecond X-ray pulsar SAX J1808.4-3658 exhibited an outburst in January and Februay of this year. The exact starting date is unknown because the source was unobservable by RXTE until 2000 Jan. 21, due to its proximity to the sun. The 401 Hz X-ray pulsations were detected in several short ...
... laboratory time from pulsars would be more easily defined if a number of pulsars with stability similar to that of the millisecond pulsar were available ...
... Proportion to n. Pulsar VLBl for Millisecond Pulsars We plan to make VLBl experiment also for millisecond pulsar. In the ...
The formation of millisecond pulsars is addressed. Evolutionary scenarios involving the spinning up of pulsars by accretion disks are discussed, and the implications of the P(dot)-P diagram for a large sample of radio pulsars are examined. 13 references.
... of the instabilities or "glitches" which reduce the utility of many pulsars as precise time references. Study of this millisecond pulsar therefore yields ...
... a pulsar time scale with a system using a small antenna. Descriptors : *RADIO BEAMS, *NEUTRON BEAMS, *MAGNETIC DIPOLES, *PULSARS, ...
... It concludes that an ensemble pulsar time based on a number of selected millisecond pulsars should have a fractional frequency stability close to 2 ...
... when the Earth happens to lie on the path of the beam. In 1982 the first element of a new class of pulsars, millisecond pulsars, was discovered, ...
A brief discussion on the characteristics of pulsars is given followed by a review of millisecond pulsar discoveries including the very first, PRS B1937+21, discovered in 1982. Methods of timing millisecond pulsars and the accuracy of millisecond ...
Observations of millisecond pulsars are discussed, taking into account a review of millisecond pulsars, arrival time observations of the 1.6 millisecond pulsar 1937 + 214, a 6.1 millisecond binary pulsar, polarimetry of the two ...
The illumination of companion stars in very low mass X-ray binaries by various kinds of radiation from the neighborhood of the neutron star after accretion has terminated or during accretion is considered. If a neutron star's spun-up period approaches 0.001 s, pulsar kHz radiation can quench accretion by pushing surrounding plasma away from the neutron star, and may ...
Accretion-powered millisecond pulsars (AMPs) are very interesting astrophysical objects. Mat-ter from accretion disk is captured by star's magnetic field and falls along the field lines, creating "hotspots" near magnetic poles of the star. Typical spectrum of an AMP contains a disk emis-sion, blackbody emission of a hotspot and a ...
We report on possible orbit solutions of the new accretion powered millisecond pulsar IGR J17498-2921 (ATEL #3551, #3555, #3556, #3558, #3559, #3560). We used RXTE PCA observations from 2011-08-13 (Papitto et al., ATEL #3556) and 2011-08-15 at 20:20 for 3.8 ks exposure. The pulsation signal is strongly detected ...
Over 5 years of daily hard X-ray (>20 keV) monitoring of the 2 minute accretion-powered pulsar GX
NASA Technical Reports Server (NTRS)
Simulations of the Galactic pulsar population are reviewed. These include snapshot and time-dependent models of normal pulsars as well as binary and milli-second pulsars.
The discovery of millisecond pulsations from neutron stars in low mass X-ray binary (LMXB) systems has substantiated the theoretical prediction that links millisecond radio pulsars (MSRPs) and LMXBs. Since then, the process that produces millisecond radio pulsars from LMXBs, followed by ...
Millisecond pulsars have attracted attention as future reference clocks in place of present atomic clocks. The Communications Research Laboratory (CRL) has been developing an observation system to measure the pulse timing of a millisecond pulsar precisely...
National Technical Information Service (NTIS)
We review the application of millisecond pulsars to define a precise long-term time standard and positional reference system is nearly inertial reference frame. We quantify the current timing precision of the best millisecond pulsars and define the requir...
This grant, titled 'X-Ray Emission from Two Nearby Millisecond Pulsars,' included ROSAT observations
Isolated (solitary or non-accreting) millisecond pulsars with observed X-ray emission can be divided
The 2002 outburst of the accretionpowered millisecond pulsar SAX J1808.43658. Askar Ibragimov and prof. Juri Poutanen. University of Oulu, Finland ...
NASA Website
... of planetary companions around the nearby millisecond radio pulsar PSR B1257 ... If planetary formation is common around millisecond pulsars and if ...
... Millisecond pulsars are expected to supply a source ... Another millisecond pulsar PSR1713+07 has been ... QZS orbit projected onto the earth and the ...
... Millisecond pulsars attract attentions as a future reference clock in place of prwnt atomic clocks, by reason of their highly stable pulse timing. ...
Mar 4, 2003 ... For about 20 years astrophysicists have suspected that the most rapidly spinning neutron stars known, the millisecond radio pulsars, ...
... the discovery of the millisecond pulsar, PSR 1937 ... on frequency stability between millisecond pulsars and atomic clocks on or near the earth. ...
A unified description of the properties of 14 X-ray pulsars is presented and compared with the current theoretical understanding of these systems. The sample extends over six orders of magnitude in luminosity, with the only trend in the phase averaged spe...
Jul 2, 2003 ... Caption for Animation 1: ACCRETION SPINS PULSAR TO MILLISECOND RANGE. If a pulsar -- a dense star with strong gravitational attraction -- is ...
... For Earth-bound clocks, this is limited to some ... Millisecond pulsars can be wed as stable clocks to ... to understanding how such a pulsar time scale ...
pulsars. Its October 2002 outburst is of particular interest because of the discovery of kilohertz quasi-periodic oscillations ...
Neutron Stars, Pulsars, Millisecond Pulsars, and Gravitational Radiation: GLOSSARY. Accretion disk: The flattened, pancake-like structure formed by matter ...
millisecond binary pulsar challenges the standard model of pulsar formation. Pulsars are rapidly spinning with periods ranging from about 1 ms to 8 s. Of the ~1600 pulsars known in the disk of our galaxy, some 5% have pulse periods shorter than 10 ms (1). Most of these ...
E-print Network
The Rossi X-ray Timing Explorer has observed five outbursts from the transient 2.5 ms accretion-powered pulsar SAX J1808.4-3658 during 1998-2008. We present a pulse timing study of the most recent outburst and compare it with the previous timing solutions. The spin frequency of the source continues to decrease at a rate of (-5.5 {+-} 1.2) x 10{sup -18} Hz ...
Population of Rotation-powered Pulsars and Magnetars ... Normal and millisecond pulsars. - Review Emission Models, Comparison with. Observations ...
... to 15,000 light year path from the pulsar to the ... FREE ELECTRONS, RANDOM WALK, INTERSTELLAR SPACE, PULSARS, DATA ACQUISITION ...
... It is not practical to derive exact numerical values for the stability of pulsars because the pulsar timing data are actually residuals to a multi ...
The following topics were dealt with: pulsar progenitors, pulsar/SNR associations, pulsar velocities, pulsar beam shape, magnetospheric models, radio emission models, millisecond pulsar radiation properties, gamma-ray pulsars, timing noise and glitches, ...
drift is apparent in the Short High pulses showing that a re ned period can be ... Figure 5 shows a sequence of Uhuru pulses from 3] from a single Main High ...
from PSR 1257+12 suggested that there were two Earth�mass planets around this pulsar (Wolszczan & FrailImplications of the PSR 1257+12 Planetary System for Isolated Millisecond Pulsars M. Coleman Miller@astro.umd.edu,hamilton@astro.umd.edu ABSTRACT The first extrasolar planets were discovered in 1992 around the ...
Binary and Millisecond Pulsars D. R. Lorimer Max Planck Institut fur Radioastronomie, Auf dem H, Germany Abstract Our knowledge of binary and millisecond pulsars has greatly increased in re- cent years pulsars turn out to be superb celestial clocks. In this review we summarise the main ...
The nature of pulsars that exhibit quasi-periodic oscillations (QPOs) is discussed. It is shown how QPOs are produced by an interaction between the accretion disk surrounding a neutron star with the neutron star's magnetic field. The possible relationship between pulsars that exhibit QPOs and millisecond ...
A Sequence of Outbursts from the Transient X�Ray Pulsar GS 0834--430 Colleen A. Wilson, Mark H accretion�powered pulsar, has been observed in seven outbursts with the BATSE large area detectors on the Compton Gamma Ray Observatory. The first 5 outbursts observed by BATSE occurred at intervals of about 107
The twelfth accretion-powered millisecond pulsar, IGR J17511-3057, was discovered in 2009 September. In this work we study its spectral and timing properties during the 2009 outburst based on Swift and RXTE data. Our spectral analysis of the source indicates only slight spectral shape evolution during the entire outburst. The ...
We report on the discovery and the timing analysis of the first eclipsing accretion-powered millisecond X-ray pulsar (AMXP): SWIFT J1749.4-2807. The neutron star rotates at a frequency of ~517.9 Hz and is in a binary system with an orbital period of 8.8 hr and a projected semimajor axis of ~1.90 lt-s. Assuming a neutron star between ...
75 Chapter 6 Discovery of a 5.9�ms Pulsar 1 6.1 Introduction The surveys described in Chapters 4 and 5 were designed to have excellent sen� sitivity to millisecond pulsars. Understanding the formation and evolution of millisecond pulsars requires a large sample of ...
In this paper we report on our analysis of three Chandra observations of the accretion-powered millisecond X-ray pulsar IGR J00291+5934 obtained during the late stages of the 2004 outburst. We also report the serendipitous detection of the source in quiescence by ROSAT during MJD 48830-48839 (1992 July 26-August 4). The detected 0.3-10 keV source count ...
... Hamilton 2001; Hansen 2002), but all generally rely on an accretion disk around the pulsar within which the planets form. Millisecond pulsars are a ...
... The pulsar PSR B1257+12 is orbited by three planets, and other millisecond pulsars may be orbited by dust disks that represent planets that failed ...
The author describes the role pulsars might play in time and frequency technology. Millisecond pulsars are rapidly rotating neutron stars: spherical flywheels some 20 km in diameter, 1.4 times as massive as the Sun, and spinning as fast as several thousand radians per second. Radio noise generated in a pulsar's ...
IAUC 4892 available at Central Bureau for Astronomical Telegrams. IAUC 4892 available at Central Bureau for Astronomical Telegrams.
that this is already greater than one Earth mass, this may mean that isolated millisecond pulsars either have planetary MILLISECOND PULSARS M. COLEMAN MILLER AND DOUGLAS P. HAMILTON Department of Astronomy, University of Maryland the millisecond pulsar PSR 1257]12. We show ...
We have detected an x-ray nebula around the binary millisecond pulsar B1957+20. A narrow tail, corresponding to the shocked pulsar wind, is seen interior to the known Halpha bow shock and proves the long-held assumption that the rotational energy of millisecond pulsars is dissipated through ...
PubMed
The discovery of millisecond pulsations from neutron stars in low mass X-ray binaries (LMXBs) has substantiated the theoretical prediction that links millisecond radio pulsars (MSRPs) and LMXBs. Since then, the recycling process that produces MSRPs on a spin-up region from LMXBs, followed by spin-down due to dipole radiation has been ...
The Parkes Pulsar Timing Array project aims to make a direct detection of a gravitational wave background through the timing of millisecond pulsars. In this paper, the main requirements for that endeavour are described and recent and ongoing progress is outlined. We demonstrate that the timing properties of ...
SEARCHING FOR MILLISECOND PULSARS IN GAMMA-RAY DATA USING THE FERMI LAT A Thesis Submitted Pulsar Searches With Fermi 2 Abstract When professor Antony Hewish of Cambridge University set out of their time. The association of their discrete radio signal with a Pulsar, then only a theorized entity
Dense stellar systems such as globular clusters are known to produce many more millisecond pulsars per mass than galaxies. We have begun investigations, theoretically, into the formation and evolution of binary pulsars, and in particular millisecond pulsars. We present preliminary results of ...
A pulsar with a period of about 1.556 milliseconds has been discovered. The discovery of the pulsar has cleared up the mystery surrounding the enigmatic source, 4C21.53. An exposition of the history of the search process, results from the timing program, the pulse waveform, the distance and the origin of the pulsar ...
61 Chapter 5 Discovery of Fourteen Pulsars in Drift Surveys From Arecibo 1 5.1 Introduction with excellent, and consistent sensitivity to millisecond pulsars. This chapter reports on the completion. The most interesting result of the survey so far is the discovery of a binary, millisecond ...
Dec 15, 2010 ... Thesis: ``The Wind Interaction Regions of the Vela Pulsar: a Pulsar Jet and Bow Shock ... RXTE PCA studies of millisecond X-ray pulsars ...
We present a timing solution for the 598.89 Hz accreting millisecond pulsar, IGR J00291+5934, using Rossi X-ray Timing Explorer data taken during the two outbursts exhibited by the source on 2008 August and September. We estimate the neutron star spin frequency and we refine the system orbital solution. To achieve the highest possible accuracy in the ...
The accretion-powered millisecond pulsar IGR J00291+5934 underwent two ~10 day long outbursts during 2008, separated by 30 days in quiescence. Such a short quiescent period between outbursts has never been seen before from a neutron star X-ray transient. X-ray pulsations at the 599 Hz spin frequency are detected throughout both outbursts. For the first ...
Polarization profiles are presented for 20 millisecond pulsars that are being observed as part of the Parkes Pulsar Timing Array project. The observations used the Parkes multibeam receiver with a central frequency of 1369 MHz and the Parkes digital filter bank pulsar signal-processing system PDFB2. Because of the ...
The Fermi satellite has detected more than 600 unidentified gamma-ray sources. We know that many of these will be associated with the most energetic and fascinating radio pulsars. By selecting the gamma-ray pulsars showing pulsar-like properties we expect to discover tens of new millisecond and young, energetic ...
, this means the fastest millisecond pulsars are visible up to 1kpc from the earth (see fig. 3). As manywith Ben Stappers We investigate the number and type of pulsars that will be discovered will find approximately 1500 new pulsars, probing the local population of pulsars to a very deep ...
Whirling away at unbelievable speeds, pulsars presented a mystery that required both imagination and precise observation to solve. In this paper, the author gives a review of pulsars from their first discovery in 1968 to today. He also discusses the star models that evolved to explain the pulsar phenomena. Included is the discovery in ...
We review recent results from the X-ray timing of accreting millisecond pulsars in LMXBs. This is the first time a timing analysis is performed on accreting millisecond pulsars, and for the first time we can obtain information on the behavior of a very fast pulsar subject to accretion torques. ...
We propose to carry out the most ambitious and comprehensive all-sky survey for pulsars and transient sources to date. Using the 20cm multibeam and a new digital filterbank array this survey will create a petabyte digital record of the sky that can be data mined in the future and used to search for relativistic binary and millisecond ...
This grant, titled 'X-Ray Emission from Two Nearby Millisecond Pulsars,' included ROSAT observations of the nearby pulsars PSR J2322+20 and PSR J2019+24. Neither was detected, although the observations were among the most sensitive ever made towards milli...
This proposal concentrates the timing observations of binary and millisecond pulsars discovered by us in the Parkes Multibeam (PKSMB) and high-latitude (PH) surveys. In order to fully exploit the scientific promises of our discoveries it is essential to perform continued timing observations. It is crucial that the observing sessions be spaced at ...
We present an evolutionary scenario for the spin-up and evolution of binary millisecond pulsars, according to which the companion of the pulsar PSR J1740-5340 , recently discovered as a binary with orbital period of 32.5 hrs in the Globular Cluster NGC 6397, is presently in a phase of `radio--ejection' mass loss from the system.
I review the basic observational properties of accreting millisecond pulsars that are important for understanding the physics involved in formation of their pulse profiles. I then discuss main effects responsible for shaping these profiles. Some analytical results that help to understand the results of simulations are presented. Constraints on the ...
We present results of our pulsar population synthesis of normal and millisecond pulsars in the Galactic plane. Over the past several years, a program has been developed to simulate pulsar birth, evolution and emission using Monte Carlo techniques. We have added to the program the capability to simulate ...
We have embarked on a survey for pulsars and fast transients using the 13-beam multibeam receiver on the Parkes Radio Telescope. Installation of a digital backend allows us to record 400 MHz of bandwidth for each beam, split into 1024 channels and sampled every 64 ?s. Limits of the receiver package restrict us to a 340 MHz observing band centred at 1352 MHz. The factor of 8 ...
Millisecond pulsars are attractive as future reference clocks, because of their highly stable pulse timing. Communications Research Laboratory (CRL) aims to apply millisecond pulsars to the construction of a new time scale, and have developed a millisecond pulsar ...
We propose measuring the average profile stabilization rate in millisecond pulsars. We consider the correlations between a pulsar's global average profile and subaverage profiles constructed using increasing numbers of pulses, thereby quantifying the number of pulses required to build a stable average profile. We adopt the methodology ...
We present results of our pulsar population synthesis of normal and millisecond pulsars from the Galactic disk using our previously developed computer code. Over the past several years, a program has been developed to simulate pulsar birth, evolution and emission using Monte Carlo techniques. We have added to the ...
The thermal emission detected from the millisecond pulsar J0437-4715 is not explained by standard cooling models of neutron stars without a heating mechanism. We investigated three heating mechanisms controlled by the rotational braking of the pulsar: breaking of the solid crust, superfluid vortex creep, and non-equilibrium reactions ...
Jan 5, 2010 ... Millisecond pulsars are nature's most precise clocks, with long-term, sub- microsecond stability that rivals human-made atomic clocks. ...
The identification of Geminga, the discovery of X-ray emission from millisecond pulsars and the identification of cooling neutron stars are only a few of ...
IAUC 4735 available at Central Bureau for Astronomical Telegrams. IAUC 4735 available at Central Bureau for Astronomical Telegrams.
... 4. TITLE AND SUBTITLE Search for Protoplanetary and Debris Disks Around Millisecond Pulsars 5a. CONTRACT NUMBER 5b. GRANT NUMBER ...
... 1 millisecond event-by-event or EBE ... relative phases of these events calculated from ... instrument response model which ignored Compton scattering. ...
Jan 5, 2010 ... Radio astronomers have uncovered 17 millisecond pulsars in our galaxy that could be used as a kind of "galactic GPS" to detect gravitational ...
... As atomic clocks were shown to be more accurate and stable than those based on astrometry, the SI second was redefined.[l] It now seems that an ...
49. Discovery of Two Planets Around a Millisecond. Pulsar. A. Wolszczan .... and the titanium carbide, we can show that the titanium carbide ...
Not available, thesis can be downloaded directly from http://www.oso.chalmers.se/~curran/mastersthesis.ps.gz
Jan 8, 2010 ... Millisecond pulsars are nature's most precise clocks, with long-term, sub- microsecond stability that rivals human-made atomic clocks. ...
Oct 25, 2005 ... GOF, RXTE Finds the First Millisecond Pulsar in an Accreting X-ray ... the times at which the signals from the pulsar arrival at the Earth. ...
Oct 16, 2008 ... Its lighthouse-like beam sweeps Earth's way every 316.86 milliseconds. The pulsar, which formed about 10000 years ago, emits 1000 times the ...
New method of precise clocks comparison based on observation and registration of giant pulses of the millisecond pulsars is discussed. It was shown that expected accuracy of comparison is about 0.2-2 ns and depends on uncertainty of delay in the Earth ionosphere and troposphere.
By timing the arrival of radio signals from a rapidly spinning pulsar at the Arecibo Observatory's radio/radar telescope, the most convincing evidence so far for a planetary system outside our own has been found: two or possibly three planets that orbit t...
Millisecond pulsars are believed to descend from low-mass X-ray binaries. Observable parameters of binary millisecond pulsars, e.g. mass of the pulsar, mass of the companion, spin period of the pulsar, orbital period, orbital eccentricity, etc., are used to probe the past ...
Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched ...
Searching for weak, isolated pulsars in the globular cluster Terzan 5 Benjamin Sulman (Oberlin. It contains 33 known recycled millisecond pulsars, 16 of which are binary systems. We searched for very weak, isolated pulsars in Terzan 5 using an incoherent "stack-search" method that sums power spectra from several
RADIO PULSAR POPULATION PROPERTIES D. R. LORIMER Max--Planck--Institut f�ur Radioastronomie, Auf pulsars. The sample is strongly biased by selection effects which must be understood and corrected successful in finding low�luminosity, millisecond and binary pulsars and we summarise some recent results
PULSAR VELOCITIES D. R. Lorimer Max--Planck--Institut f�ur Radioastronomie, Auf dem H�ugel 69, D suggesting that the distribution of pulsar velocities at birth ranges from zero to over 1000 km s \\Gamma1 of millisecond and binary pulsars and their progenitors. For other recent reviews on this subject, see ...
We present results of our population synthesis of normal and millisecond pulsars from the Galactic disk. Over the past several years, a program has been developed to simulate pulsar birth, evolution, and emission using Monte Carlo techniques. We have added to the program the capability to simulate millisecond ...
The present conference considers topics in the fields of rotation-powered pulsars, the relationship of pulsars to SNRs, accretion-powered pulsars, neutron-star formation in theoretical SNs, neutrol stellar evolution, neutron star physics, and other manifestations of neutron stars and their place in neutron star ...
We will describe a Thomson X-ray polarimeter developed for a small satellite mission. The instrument works in the 5-30 keV band and will be suitable for X-ray polarisation measurement in about 50 hard X-ray sources. The accretion powered X-ray pulsars, black hole X-ray binaries, rotation powered pulsars and ...
Pulsar astrophysics has come a long way in the 40 years since the discovery of the first pulsar by Bell and Hewish. From humble beginnings as bits of 'scruff' on the Cambridge University group's chart recorder paper, the field of pulsars has blossomed into a major area of mainstream astrophysics, with an unparalleled diversity of ...
We report here a study of the long term properties of Quasi Periodic Oscillations (QPO) in an unusual accreting X-ray pulsar, 4U 1626-67. This is a unique accretion powered X-ray pulsar in which we have found the QPOs to be present during all sufficiently long X-ray observations with a wide range of X-ray ...
Recent data on low-mass X-ray binaries (LMXBs) and millisecond pulsars (MSPs) pose a challenge to evolutionary theories which neglect the effects of disk and comparison irradiation. Here we discuss the main features of a radiation-driven (RD) evolutionary...
Binary stars play an essential role during the late phases of the dynamical evolution of a globular cluster. Hard binaries are known to exist in cluster cores, e.g., in the form of millisecond pulsars (about half of the millisecond pulsars observed in 47 ...
It is now more than eleven years since the discovery of the first accreting millisecond X-ray pulsar. Since then, eleven additional systems have been found, two of them during the last year. Here I briefly discuss the most recent developments with respect to these systems.
We have used the Green Bank Telescope at 350 MHz to search 50 faint, unidentified Fermi ?-ray sources for radio pulsations. So far, these searches have resulted in the discovery of 10 millisecond pulsars, which are plausible counterparts to these unidentified Fermi sources. Here we briefly describe this survey and the characteristics of the newly ...
The AGILE ?-ray satellite provides large sky exposure levels (>=109 cm2 s per year on the Galactic Plane) with sensitivity peaking at E ~100 MeV where the bulk of pulsar energy output is typically released. Its ~1 ?s absolute time tagging capability makes it perfectly suited for the study of ?-ray pulsars. AGILE collected a large number of ?-ray photons ...
We present the new pulsars discovered in the 350-MHz survey with the Green Bank Telescope. The survey took advantage of the time available during the track refurbishing during the Northern hemisphere summer of 2007. So far we have discovered 26 new pulsars, including 5 millisecond pulsars, 6 binary ...
Millisecond pulsars are attractive for use as future reference clocks because of their highly stable pulse timing. Communications Research Laboratory (CRL) aims to apply millisecond pulsars to the construction of a new time scale, and has developed a millisecond pulsar ...
We present results of our pulsar population synthesis of millisecond pulsars in the Galactic plane using our previously developed computer code. Over the past several years, a program has been developed to simulate pulsar birth, evolution and emission using Monte Carlo techniques. We have added to the program the ...
r-mode instabilities in rapidly rotating quark matter stars (strange stars) lead to specific signatures in the evolution of pulsars with periods below 2.5 msec, and may explain the apparent lack of very rapid pulsars. Existing data seem consistent with pulsars being strange stars with a normal quark matter phase surrounded by an ...
We have detected the optical companion of the eclipsing millisecond pulsar J2051-0827. The amplitude of the companion's light curve is at least 1.2 mag, and the variation is consistent with the companion's rotating synchronously about the pulsar and one side being heated by the impinging pulsar flux. PSR J2051-0827 ...
Pulsars are unique in that they act as celestial laboratories for precise tests of gravity and other extreme physics (Kramer 2004). There are approximately 2000 known pulsars today, which is less than ten percent of pulsars in the Milky Way according to theoretical models (Lorimer 2004). Out of these 2000 known ...
The NANOGrav consortium uses Arecibo and the GBT to make high-precision timing observations of twenty millisecond pulsars. All sources are observed at two frequencies using software coherent dedispersion systems. This program is motivated both by the search for a gravitational wave background and more traditional pulsar timing ...
The recycling model argues the existence of an evolutionary connection between low mass X-ray binaries and radio millisecond pulsars. The main difficulties which this model finds in predict the parameters of the fully recycled millisecond pulsars, as mass and spin period, can be overcome by the onset of the ...
In this work, we present a new test of the strong equivalence principle that uses the limits on the variation of the eccentricity of the orbits of wide binary millisecond pulsars to constrain any violations of the strong equivalence principle (SEP). Unlike present pulsar SEP tests, the test described here can directly detect SEP ...
The evidence for turn-over in young pulsar radio spectra at high frequencies is presented. The frequency at which a spectrum shows the maximum flux density is called the peak frequency. This peak frequency appears to depend on pulsar age and dispersion measure. A possible relation with pulsar age is interesting. ...
We have performed a Monte Carlo simulation of the Galactic population of pulsars and ?-ray observations. We apply a two-layer outer-gap model, which has been developed by Wang, Takata & Cheng, of the ?-ray emission process, and study the radiation characteristics as a function of the magnetic inclination angle (?) and the Earth viewing angle (?). In our model, the ?-ray ...
--4715 (Johnston et al. 1993) and J1713+0747 (Foster et al. 1993) --- bright, nearby millisecond pulsars which pulsar is 8.5 s (Young, #12; Manchester & Johnston 1999). Ultimately the rotational energy of the neutron, very successful at discovering young pulsars along the Galactic plane (Clifton et al. 1992; ...
Prior to the Fermi Gamma-ray Space Telescope, only six pulsars and one associated pulsar wind nebula, the Crab Nebula, had been detected in ?-rays by EGRET. Since then, the Large Area Telescope (LAT) aboard Fermi has significantly increased the number of detected pulsars in the 100 MeV to 30 GeV energy range. The new ...
The Green Bank Telescope has been used to find 68 pulsars in 13 globular clusters, the majority of them being millisecond pulsars. I report on the latest round of GBT cluster searches. Twenty clusters have been searched, some for the first time, and all more sensitively than ever before, and eight new pulsars have ...
We report the detection of a recent torque reversal to spin-up in 4U 1626-67. This is an accretion powered X-ray pulsar and shows slow gradual intensity and pulse period variation on a few years of timescale. Recently, a significant increase in the X-ray flux was observed in the long term RXTE-ASM and Swift-BAT light curve (Krimm et ...
Theoretically, the phase transition between the confined and deconfined phases of quarks can have a remarkable effect on the spin properties of millisecond pulsars and on the spin distribution of the population of x-ray neutron stars in low-mass binaries. In the latter class of stars, the effect has already been observed--a strong clustering in the ...
In millisecond pulsars the existence of the Coriolis force allows the development of the so-called Rossby oscillations (r-modes) which are know to be unstable to emission of gravitational waves. These instabilities are mainly damped by the viscosity of the star or by the existence of a strong magnetic field. A fraction of the observed ...
We report the detection of gamma-ray emissions above 200 megaelectron volts at a significance level of 17sigma from the globular cluster 47 Tucanae, using data obtained with the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Globular clusters are expected to emit gamma rays because of the large populations of millisecond pulsars that ...
Radio pulsars with millisecond spin periods are thought to have been spun up by the transfer of matter and angular momentum from a low-mass companion star during an x-ray-emitting phase. The spin periods of the neutron stars in several such low-mass x-ray binary (LMXB) systems have been shown to be in the millisecond regime, but no ...
The recycling model suggested that low-mass X-ray binaries (LMXBs) could evolve into binary millisecond pulsars (BMSPs). In this work, we attempt to investigate the progenitor properties of BMSPs formed by the recycling evolutionary channel, and if submillisecond pulsars can be produced by this channel. Using Eggleton's stellar ...
The Fermi Gamma-Ray Space Telescope has revolutionized the study of pulsar physics with the discovery of new populations of radio quiet and millisecond gamma-ray pulsars. The Fermi Large Area Telescope has so far discovered �20 new gamma-ray millisecond pulsars (MSPs) by both folding at ...
The initial motivation for this work was the reported discovery in January 1989 of a 1/2 millisecond pulsar in the remnant of the spectacular supernova, 1987A. The status of this discovery has come into grave doubt as of data taken by the same group in February, 1990. At this time we must consider that the millisecond signal does not ...
CCD photometric observations of the field of PSR 1957+20, obtained with the 1.5-m Mount Palomar telescope on June 7-9, 1988, are reported. The data are presented in tables and graphs and characterized in detail. The discovery of the optical counterpart of the pulsar by Fruchter et al. (1988) is confirmed, the period of the CCD light curve being nearly identical to the ...
General relativistic effects, due to spacetime curvature and rotation, on the arrival times of pulsar signals are investigated using a rotationally perturbed spherical metric. For the millisecond pulsar PSR 1937 + 214, the advancement in arrival time (assuming the usual polar cap model for emission mechanism and a radius-to-frequency ...
The Parkes Multibeam Pulsar Survey is the most successful survey of the Galactic plane ever performed, finding over 600 pulsars in the initial processing. We report on a reprocessing of all 40000 beams with a number of algorithms, including conventional frequency-domain searches and an acceleration search for fast binary pulsars. The ...
Timing of the dozen pulsars discovered by us in P303 is ensuring high quality results: (a) the peculiarities (in position or projected acceleration) of all the 5 millisecond pulsars in NGC6752 suggested the presence of non thermal dynamics in the core, perhaps due to black-holes of intermediate mass; (b) the eclipsing ...
We report the optical discovery of the companion to the 2 M sun millisecond pulsar PSR J1614�2230. The optical colors show that the 0.5 M sun companion is a 2.2 Gyr old He-CO white dwarf. We infer that \\dot{M} during the accretion phase is {<}10^{-2}\\,\\dot{M}_edd. We show that the pulsar was born with a spin close to its ...
Millisecond and binary pulsars are the most stable astronomical standards of frequency. They can be applied to solving a number of problems in astronomy and time-keeping metrology including the search for a stochastic gravitational wave background in the early universe, testing general relativity, and establishing a new time-scale. The full exploration of ...
Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary ...
Radio pulsars are ejected into the halo from the Galactic disk by their large birth velocities. Although the majority of them cease radio emission whilst they are still near the Galactic plane, the halo contains a large population of dead neutron stars that have completed many oscillations in the Galactic potential. The globular cluster system contains many active ...
Pulsar timing arrays act to detect gravitational waves (GWs) by observing the small, correlated effect the waves have on pulse arrival times at the Earth. We find that pulsar timing observations of GWs are able to determine the sky position and other parameters of supermassive black hole binaries with extreme accuracy, given the high-precision astrometry ...
The Australia Telescope Large Area Survey (ATLAS) team have surveyed seven square degrees of sky at 1.4GHz. During processing some unexpected infrared-faint radio sources (IFRS sources) were discovered. The nature of these sources is not understood, but it is possible that some of these sources may be pulsars within our own galaxy. We propose to observe the IFRS sources with ...
Context. Millisecond pulsars are very useful for determining the properties of neutron stars, for testing General Relativity and for detecting gravitational waves. However, the number of known millisecond pulsars is very small compared to that of ordinary pulsars. Aims: We conducted one blind ...
We study accretion-induced collapse of magnetized white dwarfs as an origin of millisecond pulsars. We apply magnetized accretion disk models to the precollapse accreting magnetic white dwarfs and calculate the white dwarf spin evolution. If the pulsar magnetic field results solely from the flux-frozen fossil white dwarf field, a ...
Recent INTEGRAL/IBIS hard X-ray surveys have detected about 10 young pulsars. We show hard X-ray properties of these 10 young pulsars, which have a luminosity of 1033-1037 erg s-1 and a photon index of 1.6-2.1 in the energy range of 20-100 keV. The correlation between X-ray luminosity and spin-down power of LX propto Lsd1.31suggests that the hard X-ray ...
Teamwork between gamma-ray and radio astronomers has produced a breakthrough in finding natural cosmic tools needed to make the first direct detections of the long-elusive gravitational waves predicted by Albert Einstein nearly a century ago. An orbiting gamma-ray telescope has pointed radio astronomers to specific locations in the sky where they can discover new millisecond ...
The search for periodic signals from rotating neutron stars or pulsars has been a computationally taxing problem to astronomers for more than twenty-five years. Over this time interval, increases in computational capability have allowed ever more sensitive searches, covering a larger parameter space. The volume of input data and the general presence of radio frequency ...
EPIC-MOS1 and MOS2 were operated in Full Frame mode pro- viding an image of an area of a $140 radius ..... 1 and text). One CCD column has a width of 4B2. ...
Jul 15, 2004 ... "X-Ray Bursts from the Accreting Millisecond Pulsar XTE J1814-338", ... ``Bounds on Compactness for LMXB Neutron Stars from X-ray Burst ...
Jan 5, 2010 ... Radio astronomers have uncovered 17 millisecond pulsars in our ... kind of " galactic GPS" to detect gravitational waves passing near Earth. ...
a soft power law before turning over around 100 MeV. The shoulder on this turnover which extends beyond 1 GeV is caused by the decrease of y to steady- state ...
In this contribution we discuss how neutron stars are produced and retained in globular clusters, outlining the most important dynamical channels and evolutionary events that affect the population of mass-transferring binaries with neutron stars and result in the formation of recycled pulsars. We confirm the importance of electron-capture supernovae in globular clusters as the ...
@clarence.gsfc.nasa.gov, craigm@milkyway. gsfc.nasa.gov. 483 The Astrophysical Journal, 619: 483�491, 2005 January 20 # 2005
Jun 6, 2008 ... Author can archive pre-print (i.e., pre-refereeing) ... must state on submission , for article to be released in PubMed Central after 6 ...
In two recent papers we have compared the multiwavelength observations of nine broad-band pulsars with the radiation spectrum generated by a polarization current that rotates faster than light in vacuo and found that this single emission process accounts quantitatively for the spectrum of each pulsar over 16-18 orders of magnitude of frequency. Here we ...
We report the optical detection of a faint star consistent with the known position of the 401 Hz transient accreting millisecond X-ray pulsar IGR J17498-2921 (ATel #3551, #3555, #3556, #3558, #3559, #3560, #3561, #3562, #3563, #3568, #3601, #3606). On 2011-08-25 and 2011-08-26 (MJD 55798.4 - 55799.5) we observed the field of IGR J17498-2921 with the 2-m ...
A 20th magnitude red object, undetectable on the Palomar Sky Survey prints, is proposed as an optical identification candidate for the millisecond pulsar. The image containing the object was obtained from three CCD exposures, one of 300 s and two of 600 s, which were filtered to remove cosmic ray events, offset into coincidence, and digitally stacked ...
millisecond pulsar SAX J1808.4-3658 during its 2002 outburst: evidence for a receding disc Askar Ibragimov1 2009 July 31. Received 2009 July 30; in original form 2008 December 29 ABSTRACT An outburst in the course of the outburst together with the reflection amplitude. These trends are in agreement
We report the parallax and proper motion of millisecond pulsar J0030+0451, one of thirteen known isolated millisecond pulsars. We obtained more than 6 years of monthly data from the 305 m Arecibo telescope at 430 MHz and 1410 MHz. We measure the parallax of PSR J0030+0451 to be 3.4�0.6 mas, corresponding to a ...
Binary pulsar systems are superb probes of stellar and binary evolution and the physics of extreme environments. In a survey with the Arecibo telescope, we have found PSR J1903+0327, a radio pulsar with a rotational period of 2.15 milliseconds in a highly eccentric (e = 0.44) 95-day orbit around a solar mass (M(middle dot in circle)) ...
We have completed sensitive searches for new pulsars in seven globular clusters using the Robert C. Byrd Green Bank Telescope, and have discovered six new recycled pulsars (four in NGC 6517 and two in M22), five of which are fully recycled millisecond pulsars with P < 10 ms. We report full timing solutions for ...
We have completed a survey for pulsars at high Galactic latitudes with the 64 m Parkes radio telescope. Observing with the 13 beam multibeam receiver at a frequency of 1374 MHz, we covered ~4150 square degrees in the region -100� <= l <= 50�, 15� <= |b| <= 30� with 7232 pointings of 265 s each, thus extending the Swinburne Intermediate Latitude ...
We have completed a survey for pulsars at high Galactic latitudes with the 64 m Parkes radio telescope. Observing with the 13 beam multibeam receiver at a frequency of 1374 MHz, we covered {approx}4150 square degrees in the region -100 deg. {<=} l {<=} 50 deg., 15 deg. {<=} |b| {<=} 30 deg. with 7232 pointings of 265 s each, thus extending the ...
We report the discovery of two millisecond pulsars in a search for radio pulsations at the positions of Fermi-Large Area Telescope sources with no previously known counterparts, using the Nan�ay Radio Telescope. The two millisecond pulsars, PSRs J2017+0603 and J2302+4442, have rotational periods of 2.896 and ...
The double pulsar system PSR J0737-3039 offers an unprecedented opportunity for studying General Relativity and neutron-star magnetospheres. This system has a favourable orbital inclination such that the millisecond pulsar, "A", is eclipsed when its slower companion, "B", passes in front. High time resolution light curves of the ...
The flat segment, lasting ~104 s, in the X-ray afterglow of GRB 051221A represents the first clear case of strong energy injection in the external shock of a short gamma-ray burst (GRB) afterglow. In this work, we show that a millisecond pulsar with a dipole magnetic field ~1014 Gauss could well account for that energy injection. The good quality X-ray ...
A large scale survey for pulsars and transients is being conducted at the Arecibo Observatory using the Arecibo L-band Feed Array (ALFA). Data acquisition so far has been with correlation spectrometers that analyze a 0.1 GHz bandwidth at 1.4 GHz. The 256 frequency channels limit dispersion smearing to 1.2 ms at DMmax = 103 pc cm-3 while the sampling interval of 64 ?s equals ...
Recent data on low-mass X-ray binaries (LMXBs) and msec pulsars (MSPs) pose a challenge to evolutionary models which neglect the effects of disk and companion irradiation. Here we discuss the main features of a radiation-driven (RD) evolutionary model tha...
PSR J1723-28 is a highly-accelerated binary millisecond radio pulsar that was discovered in the Parkes Multibeam survey. Follow-up observations taken with the Parkes and Green Bank Telescopes over the past several years have yielded only occasional detections, indicating that the pulsar is highly variable. More recently, observations ...
Five studies are reported in this final report. The recently discovered 5.3 ms pulsar J1012+5307 at a distance of 520 pc is in an area of the sky which is particularly deficient in absorbing gas. The column density along the line of sight is less than 7.5...
Millisecond pulsars, both during and after accretion, stand a class apart from the general pulsar population due to the much weaker field strength at their surface. The prevailing view is that accretion of matter on to a neutron star causes a decay of its magnetic field strength, as viewed by an external observer. In this paper we ...
We request 136 hours to survey the Large Magellanic Cloud using the 20-cm multibeam receiver together with the BPSR pulsar data recorder. This survey represents up to an order of magnitude improvement in millisecond pulsar (MSP) sensitivity over previous LMC surveys. Successful completion of this project will allow us to place new ...
