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We present an analysis of polarized X-ray pulses based on simulated data for accreting millisecond pulsars (AMPs). We used the open-source X-ray Pulse Simulation and Inference code (previously applied to NICER observations), which we…

The characteristics of the high-energy emission from polar cap accelerators will be discussed. Particles accelerated in the "slot gap" near the polar cap rim will reach altitudes of several stellar radii before initiating pair cascades,…

Astrophysics · Physics 2007-05-23 Alice K. Harding , Alexander G. Muslimov

A new picture of pulsar high-energy emission is proposed that is different from both the traditional polar cap and outer gap models, but combines elements of each. The slot gap model is based on electron acceleration along the edge of the…

Astrophysics · Physics 2009-11-10 Alice Harding , Alexander Muslimov

The partially screened vacuum gap model (PSG) for the inner acceleration region in normal radio pulsars, a variant of the pure vacuum gap model, attempts to account for the observed thermal X-ray emission from polar caps and the subpulse…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Dipanjan Mitra , Rahul Basu , George I. Melikidze , Mihir Arjunwadkar

Millisecond pulsars (MSPs) are believed to be very old neutron stars (NSs) whose age may exceed significantly $10^8$ yrs. Although cooling scenarios of isolated NSs predict for that age a surface temperature $T_s\sim 10^4$ K, observations…

High Energy Astrophysical Phenomena · Physics 2024-04-05 U. Geppert

A novel scheme has been developed to show that the observed phase behaviour associated with subpulse drifting from two pulsars, J1034$-$3224 and J1720$-$2933, can be used to obtain the magnetic field configuration in the partially screened…

High Energy Astrophysical Phenomena · Physics 2023-05-24 Rahul Basu , Dipanjan Mitra , George I. Melikidze

The majority of X-ray-detected rotation-powered millisecond pulsars (MSPs) appear to exhibit predominantly thermal emission, believed to originate from the heated magnetic polar caps of the pulsar. In the nearest MSP, J0437--4715 a faint PL…

Astrophysics · Physics 2007-05-23 Slavko Bogdanov , Jonathan E. Grindlay , George B. Rybicki

X-ray emission from many rotation-powered millisecond pulsars (MSPs) is observed to be of predominantly thermal nature. In PSR J0437--4715, the nearest MSP known, an additional faint power-law tail is observed above 2.5 keV, commonly…

Astrophysics · Physics 2011-02-11 Slavko Bogdanov , Jonathan E. Grindlay , George B. Rybicki

We modify polar cap cascade picture to include the ICS of the higher generation pairs. In such a ``full-cascade'' scenario, not only the perpendicular portion of the energy of the pairs goes to high energy radiation via SR, but the parallel…

Astrophysics · Physics 2009-10-31 Bing Zhang , Alice K. Harding

We show that a pair of thermal, antipodal hot-spots on the neutron star surface is able to fully account for the pulsar's double blackbody spectrum and energy-dependent pulse profile, including the observed 180 degree phase reversal at…

High Energy Astrophysical Phenomena · Physics 2015-05-20 E. V. Gotthelf , R. Perna , J. P. Halpern

Thermal X-ray emission from rotation-powered pulsars is believed to originate from localized "hotspots" on the stellar surface occurring where large-scale currents from the magnetosphere return to heat the atmosphere. Lightcurve modeling…

High Energy Astrophysical Phenomena · Physics 2019-11-13 Will Lockhart , Samuel E. Gralla , Feryal Özel , Dimitrios Psaltis

We complete our study of pulsars' non-uniform surface temperature and of its effects on their soft X-ray thermal emission. Our previous work had shown that, due to gravitational lensing, dipolar fields cannot reproduce the strong pulsations…

Astrophysics · Physics 2009-10-28 Dany Page , Antonio Sarmiento

Thermal radiation from hot polar caps is examined in radio pulsars with drifting subpulses. It is argued that if these subpulses correspond to sparking discharges of the inner acceleration region right above the polar cap surface then a…

Astrophysics · Physics 2007-05-23 Janusz Gil , George Melikidze , Bing Zhang

We model the temperature distribution at the surface of a magnetized neutron star and study the effects on the observable X-ray spectra and light curves, taking fully into account gravitational lensing. Only dipolar fields are considered…

Astrophysics · Physics 2009-10-22 Dany Page

We investigate the production of electron-positron pairs by inverse Compton scattered (ICS) photons above a pulsar polar cap (PC) and surface heating by returning positrons. This paper is a continuation of our self-consistent treatment of…

Astrophysics · Physics 2009-11-07 Alice K. Harding , Alexander Muslimov

Fitting the thermal X-ray spectra of neutron stars (NSs) in quiescent X-ray binaries can constrain the masses and radii of NSs. The effect of undetected hot spots on the spectrum, and thus on the inferred NS mass and radius, has not yet…

High Energy Astrophysical Phenomena · Physics 2016-08-17 K. Elshamouty , C. Heinke , S. Morsink , S. Bogdanov , A. Stevens

The study of pulsars in the three and a half decades since their discovery has highlighted a handful of issues critical to their understanding. To date there is no consensus on the physical mechanism for their radio radio emission, despite…

Astrophysics · Physics 2009-11-10 Matthew G. Baring

PSR J0108$-$1431 is an old pulsar where the X-ray emission is expected to have a thermal component from the polar cap and a non-thermal component from the magnetosphere. Although the phase-integrated spectra are fit best with a single…

High Energy Astrophysical Phenomena · Physics 2019-09-04 Prakash Arumugasamy , Dipanjan Mitra

Recent observations have found several candidates for old warm neutron stars whose surface temperatures are above the prediction of the standard neutron star cooling scenario, and thus require some heating mechanism. Motivated by these…

High Energy Astrophysical Phenomena · Physics 2020-02-20 Keisuke Yanagi , Natsumi Nagata , Koichi Hamaguchi

We present a model of thermal X-ray emission from hot spots on the surface of a rotating compact star with an unmagnetized light-element atmosphere. An application to ROSAT, Chandra, and XMM-Newton X-ray observations of the nearest known…

Astrophysics · Physics 2009-11-11 Slavko Bogdanov , George B. Rybicki , Jonathan E. Grindlay