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Observations of the thermal X-ray emission from old radio pulsars implicate that the size of hot spots is much smaller then the size of the polar cap that follows from the purely dipolar geometry of pulsar magnetic field. Plausible…

High Energy Astrophysical Phenomena · Physics 2012-07-20 Andrzej Szary , George Melikidze , Janusz Gil

Despite the fact that pulsars have been observed for almost half a century, many questions have remained unanswered. We use the analysis of X-ray observations in order to study the polar cap region of radio pulsars. The size of the hot…

High Energy Astrophysical Phenomena · Physics 2013-04-19 Andrzej Szary

The analysis of X-ray observations suggest an ultrastrong ($B\gtrsim 10^{14} \,{\rm G}$) surface magnetic field at the polar cap of pulsars (Szary, 2013). On the other hand, the temperature of the polar caps is about a few millions Kelvin.…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Andrzej Szary , George Melikidze , Janusz Gil

Magnetars are the most magnetized objects in the known universe. Powered by the magnetic energy, and not by the rotational energy as in the case of radio pulsars, they have long been regarded as a completely different class of neutron…

High Energy Astrophysical Phenomena · Physics 2015-02-20 Andrzej Szary , George I. Melikidze , Janusz Gil

The subpulse drifting phenomenon in pulsar radio emission is considered within the partially screened inner gap model, in which the sub-Goldreich-Julian thermionic flow of iron ions or electrons coexists with the spark-associated…

Astrophysics · Physics 2008-11-26 Janusz Gil , George Melikidze , Bing Zhang

We consider the problem of the thermal X-ray radiation from the hot polar cap of radio pulsars showing evidence of \EB subpulse drift in radio band. In our recent Paper I, using the partially screened gap (PSG) model of inner acceleration…

Astrophysics · Physics 2008-11-26 J. Gil , G. I. Melikidze , B. Zhang

We investigate the effect of pulsar polar cap (PC) heating produced by positrons returning from the upper pair formation front. Our calculations are based on a self-consistent treatment of the pair dynamics and the effect of electric field…

Astrophysics · Physics 2009-11-06 Alice K. Harding , Alexander G. Muslimov

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

We present spatially resolved X-ray spectra taken with the EPIC cameras of XMM-Newton of a sample of 17 cooling clusters and three non-cooling clusters for comparison. The deprojected spectra are analyzed with a multi-temperature model,…

The heating of the real polar cap surface of radio pulsars by the bombardment of ultra-relativistic charges is studied. The real polar cap is a significantly smaller area within or close by the conventional polar cap which is encircled by…

High Energy Astrophysical Phenomena · Physics 2020-07-20 Maciej Sznajder , Ulrich Geppert

Abridged) We model the X-ray properties of millisecond pulsars (MSPs) by considering hot spot emission from a weakly magnetized rotating neutron star (NS) covered by an optically-thick hydrogen atmosphere. We investigate the limitations of…

Astrophysics · Physics 2009-11-13 Slavko Bogdanov , Jonathan E. Grindlay , George B. Rybicki

We examined a model of partially screened gap region above the polar cap, in which the electron-positron plasma generated by sparking discharges coexists with thermionic flow ejected by the bombardment of the surface beneath these sparks.…

Astrophysics · Physics 2009-11-11 Janusz Gil , George Melikidze , Bing Zhang

We propose that the quiescent emission of AXPs/SGRs is powered by accretion from a fallback disk, requiring magnetic dipole fields in the range 10^{12}-10^{13} G, and that the luminous hard tails of their X-ray spectra are produced by…

High Energy Astrophysical Phenomena · Physics 2015-06-12 J. E. Truemper , K. Dennerl , N. D. Kylafis , Ü. Ertan , A. Zezas

We have investigated the evolution of a system of sparking discharges in the inner acceleration region (IAR) above the pulsar polar cap. The surface of the polar cap is heated to temperatures around $10^6$ K and forms a partially screened…

High Energy Astrophysical Phenomena · Physics 2022-09-07 Rahul Basu , George I. Melikidze , Dipanjan Mitra

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

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

The influence of surface small scale magnetic field on the heating of PSR J0250+5854 polar cap is considered. It is assumed that polar cap is heated only by reverse positrons, accelerated in pulsar diode. It is supposed that pulsar diode is…

High Energy Astrophysical Phenomena · Physics 2022-01-05 D. P. Barsukov , M. V. Vorontsov , I. K. Morozov

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
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