Pulsar Timing

Backer, D. C.

doi:10.1007/978-94-009-2273-0_1

Cited by 7 publications

(3 citation statements)

References 31 publications

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“…. This additional component is most likely not associated with the observed giant pulses of this pulsar (F. Jenet et al, in preparation) which appear to be generally delayed relative to the position of the main pulse (Backer 1995 ;Cognard et al 1996 ;Sallmen 1998). 4.2. Fast-Rotating Binary MSPs (P \ 10 ms) The steep spectrum of PSR J0218]4232, combined with its large ratio of dispersion measure to period, makes it a difficult source to observe at high radio frequencies.…”

Section: Isolated Mspsmentioning

confidence: 82%

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The Characteristics of Millisecond Pulsar Emission. III. From Low to High Frequencies

Krämer

Lange

Lorimer

et al. 1999

ApJ

152

173

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In this paper we present the Ðrst observations of a large sample of millisecond pulsars at frequencies of 2.7 GHz (11 cm) and 4.9 GHz (6 cm). For almost all sources, these represent the Ðrst 11 cm observations ever. The new measurements more than double the number of millisecond pulsars studied at 6 cm. Our new Ñux measurements extend the known spectra for millisecond pulsars to the highest frequencies to date. The coverage of more than a decade of the radio spectrum allows us for the Ðrst time to search for spectral breaks, as so often observed in normal pulsars around 1 GHz. The results suggest that, unlike normal pulsars, millisecond pulsar spectra can be largely described by a single power law. We align the observed millisecond pulsar proÐles with data from lower frequencies to search for indications of disturbed magnetic Ðelds, and attempt to resolve questions that have been raised in recent literature. Deviations from a dipolar magnetic Ðeld structure are not evident, and absolute timing across the wide frequency range with a single dispersion measure is possible. We seem to observe mainly unÐlled emission beams, which must originate from a very compact region. The existence of nondipolar Ðeld components therefore cannot be excluded. A compact emission region is also suggested by a remarkably constant proÐle width or component separation over a very wide frequency range. This observed di †er-ence from the emission properties of normal pulsars is highly signiÐcant. For a few sources, polarization data at 2.7 and 4.9 GHz could also be obtained that indicate that despite the typically larger degree of polarization at lower frequencies, millisecond pulsars are weakly polarized or even unpolarized at frequencies above 3 GHz. The simultaneous decrease in degree of polarization and the constant proÐle width thus question proposals that link depolarization and decreasing proÐle width for normal pulsars to the same propagation e †ect (i.e., birefringence). Comparing the properties of core and conal-like proÐle components to those of normal pulsars, we Ðnd less signiÐcant patterns in their spectral evolution for the population of millisecond pulsars. Hence, we suggest that core and conal emission may be created by the same emission process. Given the small change in proÐle width, the indicated depolarization of the radiation, and the possible simple Ñux density spectra, MSP emission properties tend to resemble those of normal pulsars, only shifted toward higher frequencies.

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Section: Isolated Mspsmentioning

confidence: 82%

“…In addition to studying emission properties, such measurements can provide a useful tool for high-precision timing by determining disturbing e †ects due to the interstellar weather (Backer & Wong 1998).…”

Section: Discussionmentioning

confidence: 99%

The Characteristics of Millisecond Pulsar Emission. III. From Low to High Frequencies

Krämer

Lange

Lorimer

et al. 1999

ApJ

152

173

View full text Add to dashboard Cite

show abstract

“…For a single pulsar the timing formula includes terms related to the position (α, δ), proper motion (µα, µ δ ) and parallax (π) of the pulsar. Moreover, it contains terms related to relativistic time dilation and light propagation effects in the solar system and also corrects for propagation effects in the interstellar medium (Backer 1989, Taylor 1989, Doroshenko & Kopeikin 1990:…”

Section: Introductionmentioning

confidence: 99%

A timing formula for main-sequence star binary pulsars

Wex

1998

Monthly Notices of the Royal Astronomical Society

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In binary radio pulsars with a main-sequence star companion, the spin-induced quadrupole moment of the companion gives rise to a precession of the binary orbit. As a first approximation one can model the secular evolution caused by this classical spin-orbit coupling by linear-in-time changes of the longitude of periastron and the projected semi-major axis of the pulsar orbit. This simple representation of the precession of the orbit neglects two important aspects of the orbital dynamics of a binary pulsar with an oblate companion. First, the quasiperiodic effects along the orbit, due to the anisotropic 1/r 3 nature of the quadrupole potential. Secondly, the long-term secular evolution of the binary orbit which leads to an evolution of the longitude of periastron and the projected semi-major axis which is non-linear in time.In this paper a simple timing formula for binary radio pulsars with a mainsequence star companion is presented which models the short-term secular and most of the short-term periodic effects caused by the classical spin-orbit coupling. I also give extensions of the timing formula which account for long-term secular changes in the binary pulsar motion. It is shown that the short-term periodic effects are important for the timing observations of the binary pulsar PSR B1259-63. The long-term secular effects are likely to become important in the next few years of timing observations of the binary pulsar PSR J0045-7319. They could help to restrict or even determine the moments of inertia of the companion star and thus probe its internal structure.Finally, I reinvestigate the spin-orbit precession of the binary pulsar PSR J0045-7319 since the analysis given in the literature is based on an incorrect expression for the precession of the longitude of periastron. A lower limit of 20 • for the inclination of the B star with respect to the orbital plane is derived.

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Aperiodic Time Series in Astronomy

Krolik

1992

Statistical Challenges in Modern Astronomy

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Pulsar Timing

Cited by 7 publications

References 31 publications

The Characteristics of Millisecond Pulsar Emission. III. From Low to High Frequencies

The Characteristics of Millisecond Pulsar Emission. III. From Low to High Frequencies

A timing formula for main-sequence star binary pulsars

Aperiodic Time Series in Astronomy

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