A Model for the Waveform Behavior of Accreting Millisecond X-Ray Pulsars: Nearly Aligned Magnetic Fields and Moving Emission Regions

Lamb, Frederick K.; Boutloukos, Stratos; Wassenhove, Sandor Van; Chamberlain, Robert T.; Lo, Ka Ho; Clare, A.; Yu, Wenfei; Miller, M. Coleman

doi:10.1088/0004-637x/706/1/417

Cited by 77 publications

(101 citation statements)

References 73 publications

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“…This result is compatible with theories of magnetic field evolution of MSPs in binaries: some recycled pulsars tend to have aligned magnetic filed moment, i.e., small magnetic inclination angle α (Ruderman 1991;Chen et al 1998). Lamb et al (2009) presented a concrete discussion on the α evolution of MSPs while they were recycling in low-mass X-ray binaries, and they noted that the strong interactions between spinning superfluid neutrons and magnetized superconducting protons in a pulsar's core force the spin axis to change. An MSP would be an aligned rotator (α ∼ 0…”

Section: Conclusion and Discussionsupporting

confidence: 89%

Radio and Gamma-Ray Pulsed Emission From Millisecond Pulsars

Qiao

Chen

2012

ApJ

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Pulsed γ -ray emission from millisecond pulsars (MSPs) has been detected by the sensitive Fermi space telescope, which sheds light on studies of the emission region and its mechanism. In particular, the specific patterns of radio and γ -ray emission from PSR J0101-6422 challenge the popular pulsar models, e.g., outer gap and two-pole caustic models. Using the three-dimensional annular gap model, we have jointly simulated radio and γ -ray light curves for three representative MSPs (PSR J0034-0534, PSR J0101-6422, and PSR J0437-4715) with distinct radio phase lags, and present the best simulated results for these MSPs, particularly for PSR J0101-6422 with complex radio and γ -ray pulse profiles, and for PSR J0437-4715 with a radio interpulse. We have found that both the γ -ray and radio emission originate from the annular gap region located in only one magnetic pole, and the radio emission region is not primarily lower than the γ -ray region in most cases. In addition, the annular gap model with a small magnetic inclination angle instead of an "orthogonal rotator" can account for the MSPs' radio interpulse with a large phase separation from the main pulse. The annular gap model is a self-consistent model not only for young pulsars but also MSPs, and multi-wavelength light curves can be fundamentally explained using this model.

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Section: Conclusion and Discussionsupporting

confidence: 89%

Radio and Gamma-Ray Pulsed Emission From Millisecond Pulsars

Qiao

Chen

2012

ApJ

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“…Pulse-profile modeling techniques have been used to explore the surface emission properties in many types of neutron stars, such as slow pulsars (Page 1995), magnetars (DeDeo et al 2001;Ozel et al 2001), rotation-powered millisecond pulsars (Pavlov & Zavlin 1997;Bogdanov et al 2007), X-ray bursters (Weinberg et al 2001;Nath et al 2002;Muno et al 2002Muno et al , 2003, and accretion-powered millisecond pulsars (Poutanen & Gierliński 2003;Bhattacharyya et al 2005;Leahy et al 2008Leahy et al , 2009Leahy et al , 2011Lamb et al 2009;. This technique also defines the key scientific objectives of several upcoming or proposed X-ray missions, such as NASA's NICER (Gendreau et al 2012), ESA's LOFT (Feroci et al 2012), and ISRO's Astrosat (Agrawal 2006), which aim to measure the masses and radii of several millisecond rotation-powered pulsars and X-ray bursters with high precision.…”

Section: Introductionmentioning

confidence: 99%

Pulse Profiles From Spinning Neutron Stars in the Hartle-Thorne Approximation

Psaltis

Özel

2014

ApJ

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We present a new numerical algorithm for the calculation of pulse profiles from spinning neutron stars in the Hartle-Thorne approximation. Our approach allows us to formally take into account the effects of Doppler shifts and aberration, of frame dragging, as well as of the oblateness of the stellar surface and of its quadrupole moment. We confirm an earlier result that neglecting the oblateness of the neutron-star surface leads to 5%-30% errors in the calculated profiles and further show that neglecting the quadrupole moment of its spacetime leads to 1%-5% errors at a spin frequency of 600 Hz. We discuss the implications of our results for the measurements of neutron-star masses and radii with upcoming X-ray missions, such as NASA's NICER and ESA's LOFT.

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“…A limit case is MSP SAX J1808.4-3658 displaying spin up and spin down phases (Di Salvo et al 2008). More details on the rich phenomenology of accreting millisecond pulsars can be found in the work of Lamb and colleagues (Lamb et al 2009). …”

Section: Pulsar Behaviormentioning

confidence: 99%

Pulsar positioning system: a quest for evidence of extraterrestrial engineering

Vidal

2017

International Journal of Astrobiology

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Pulsars have at least two impressive applications. First, they can be used as highly accurate clocks, comparable in stability to atomic clocks; secondly, a small subset of pulsars, millisecond X-ray pulsars, provide all the necessary ingredients for a passive galactic positioning system. This is known in astronautics as X-ray pulsar-based navigation (XNAV). XNAV is comparable to GPS, except that it operates on a galactic scale. I propose a SETI-XNAV research program to test the hypothesis that this pulsar positioning system might be an instance of galactic-scale engineering by extraterrestrial beings (section 4). The paper starts by exposing the basics of pulsar navigation (section 2), continues with a critique of the rejection of the extraterrestrial hypothesis when pulsars were first discovered (section 3). The core section 4 proposes lines of inquiry for SETI-XNAV, related to: the pulsar distribution and power in the galaxy; their population; their evolution; possible pulse synchronizations; pulsar usability when navigating near the speed of light; decoding galactic coordinates; directed panspermia; and information content in pulses. Even if pulsars are natural, they are likely to be used as standards by ETIs in the galaxy (section 5). I discuss possible objections and potential benefits for humanity, whether the research program succeeds or not (section 6).

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A Model for the Waveform Behavior of Accreting Millisecond X-Ray Pulsars: Nearly Aligned Magnetic Fields and Moving Emission Regions

Cited by 77 publications

References 73 publications

Radio and Gamma-Ray Pulsed Emission From Millisecond Pulsars

Radio and Gamma-Ray Pulsed Emission From Millisecond Pulsars

Pulse Profiles From Spinning Neutron Stars in the Hartle-Thorne Approximation

Pulsar positioning system: a quest for evidence of extraterrestrial engineering

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