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Observations of the thermal X-ray emission from 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. Most plausible…

High Energy Astrophysical Phenomena · Physics 2011-11-23 Andrzej Szary , George I. Melikidze , Janusz Gil

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

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 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 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

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 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 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 radio emission in many pulsars show sudden changes, usually within a period, that cannot be related to the steady state processes within the inner acceleration region (IAR) above the polar cap. These changes are often quasi-periodic in…

High Energy Astrophysical Phenomena · Physics 2021-06-09 U. Geppert , R. Basu , D. Mitra , G. Melikidze , M. Szkudlarek

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

We present a detailed study of the X-ray emission from PSR B1055-52 using XMM-Newton observations from 2019 and 2000. The phase-integrated X-ray emission from this pulsar is poorly described by existing neutron star atmosphere models.…

High Energy Astrophysical Phenomena · Physics 2024-01-24 Armin Vahdat , Bettina Posselt , George G. Pavlov , Patrick Weltevrede , Andrea Santangelo , Simon Johnston

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,…

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 show that the soft X-ray spectra and light curves observed with the ROSAT and EUVE from the closest known millisecond pulsar J0437--4715 can be interpreted as thermal radiation from two hot polar caps whose emitting layers (atmospheres)…

Astrophysics · Physics 2008-02-03 V. E. Zavlin , G. G Pavlov

It is shown that for moderately hot polar caps (with effective temperature of $\sim 10^6$ K), the efficiency of polar gap acceleration is lower compared to the case in which the polar caps are relatively cool and inverse Compton scattering…

Astrophysics · Physics 2015-06-24 Q. Luo , R. J. Protheroe

The radio-quiet pulsar PSR J2021+4026 is mostly known because it is the only rotation-powered pulsar that shows variability in its {\gamma}-ray emission. Using XMM-Newton archival data, we first confirmed that its flux is steady in the…

High Energy Astrophysical Phenomena · Physics 2021-02-17 Michela Rigoselli , Sandro Mereghetti , Roberto Taverna , Roberto Turolla , Davide De Grandis

We constrain the X-ray properties of the nearby $(360\,{\rm pc})$, old ($5\,{\rm Myr}$) pulsar B1133+16 with $\sim 100\,{\rm ks}$ effective exposure time by {\it XMM-Newton}. The observed pulsar flux in the 0.2-3 keV energy range is $\sim…

High Energy Astrophysical Phenomena · Physics 2017-02-08 Andrzej Szary , Janusz Gil , Bing Zhang , Frank Haberl , George I. Melikidze , Ulrich Geppert , Dipanjan Mitra , Ren-Xin Xu

I present an analysis of the deepest X-ray exposure of a radio millisecond pulsar (MSP) to date, an X-ray Multi Mirror-Newton European Photon Imaging Camera spectroscopic and timing observation of the nearest known MSP, PSR J0437--4715. The…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Slavko Bogdanov
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