The Radio and X-ray Mode-Switching Pulsar PSR B0943+10

Mereghetti, S.; Rigoselli, Michela

doi:10.1007/s12036-017-9464-7

Cited by 6 publications

(6 citation statements)

References 49 publications

(101 reference statements)

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“…The weaker constraints on geometry angles have to be taken into account when the unexpectedly large fractional amplitude of the thermal X-ray emission from the polar caps of PSR B0943+10 is explained (Hermsen et al 2013;Mereghetti et al 2016;Mereghetti & Rigoselli 2017). Another interesting constraint on the PSR B0943+10 geometry may come from directly modelling the X-ray light curve.…”

Section: Discussionmentioning

confidence: 99%

PSR B0943+10: low-frequency study of subpulse periodicity in the Bright mode with LOFAR

Bilous

2018

A&A

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We use broadband sensitive LOFAR observations in the 25-80 MHz frequency range to study the single-pulse emission properties of the mode-switching pulsar B0943+10. We review the derivation of magnetospheric geometry, originally based on low-frequency radio data, and show that the geometry is less strongly constrained than previously thought. This may be used to help explain the large fractional amplitudes of the observed thermal X-ray pulsations from the polar cap, which contradicted the almost aligned rotator model of PSR B0943+10. We analyse the properties of drifting subpulses in the Bright mode and report on the short-scale (minutes) variations of the drift period. We searched for the periodic amplitude modulation of drifting subpulses, which is a vital argument for constraining several important system parameters: the degree of aliasing, the orientation of the line-of-sight vector with respect to magnetic and spin axes, the angular velocity of the carousel, and thus, the gradient of the accelerating potential in the polar gap. The periodic amplitude modulation was not detected, indicating that it may be a rare or narrow-band phenomenon. Based on our non-detection and review of the available literature, we chose to leave the aliasing order unconstrained and derived the number of sparks under different assumptions about the aliasing order and geometry angles. Contrary to the previous findings, we did not find a large (of the order of 10%) gradual variation of the separation between subpulses throughout Bright mode. We speculate that this large variation of subpulse separation may be due to the incorrect accounting for the curvature of the line of sight within the on-pulse window. Finally, we report on the frequency-dependent drift phase delay, which is similar to the delay reported previously for PSR B0809+74. We provide a quantitative explanation of the observed frequency-dependent drift phase delay within the carousel model.

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Section: Discussionmentioning

confidence: 99%

PSR B0943+10: low-frequency study of subpulse periodicity in the Bright mode with LOFAR

Bilous

2018

A&A

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“…Although there are no simultaneous radio data for the 2003 observations, the average X-ray flux measured in December 2003 suggests that the pulsar was in the B-mode for most of the time (Mereghetti & Rigoselli 2017). In principle, we could have added these data to those analyzed here, but also in view of their short exposure, we decided to restrict our analysis to the 2011 and 2014 data sets for which the mode identification based on radio observations is certain.…”

Section: Observations and Data Analysismentioning

confidence: 99%

Thermal Emission and Magnetic Beaming in the Radio and X-Ray Mode-switching PSR B0943+10

Rigoselli

Mereghetti

Turolla

et al. 2019

ApJ

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PSR B0943+10 is a mode-switching radio pulsar characterized by two emission modes with different radio and X-ray properties. Previous studies, based on simple combinations of blackbody and power law models, showed that its X-ray flux can be decomposed in a pulsed thermal plus an unpulsed non-thermal components. However, if PSR B0943+10 is a nearly aligned rotator seen pole-on, as suggested by the radio data, it is difficult to reproduce the high observed pulsed fraction unless magnetic beaming is included. In this work we reanalyze all the available X-ray observations of PSR B0943+10 with simultaneous radio coverage, modeling its thermal emission with polar caps covered by a magnetized hydrogen atmosphere or with a condensed iron surface. The condensed surface model provides good fits to the spectra of both pulsar modes, but, similarly to the blackbody, it can not reproduce the observed pulse profiles, unless an additional power law with an ad hoc modulation is added. Instead, the pulse profiles and phase-resolved spectra are well described using the hydrogen atmosphere model to describe the polar cap emission, plus an unpulsed power law. For the X-ray brighter state (Q-mode) we obtain a best fit with a temperature kT ∼ 0.09 keV, an emitting radius R ∼ 260 m, a magnetic field consistent with the value of the dipole field of 4 × 10 12 G inferred from the timing parameters, and a small angle between the magnetic and spin axis, ξ = 5 • . The corresponding parameters for the X-ray fainter state (B-mode) are kT ∼ 0.08 keV and R ∼ 170 m.

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“…For timely detection and identification of gamma-ray bursts and other transient events caught in the field of view of the IBIS and SPI telescopes, as well as for urgent notification of them via electronic GCN (Gammaray Coordinates Network) circulars the IBAS automatic software system was developed (Mereghetti et al 2003) and is now successfully used. Yet there is always a possibility to independently search for bursts in just received or even archival data of the telescopes.…”

Section: Instruments and Methodsmentioning

confidence: 99%

“…Although some gamma-ray bursts are successfully detected by the SPI gamma-ray spectrometer and IBIS-ISGRI gamma-ray telescope within their fields of view (e.g., Mereghetti et al 2003;Foley et al 2008Foley et al , 2009Vianello et al 2009;Minaev et al, 2014) and beyond (e.g., Minaev et al 2014;Chelovekov et al 2019b), significantly more of them are registered by anticoincidence shield ACS of the SPI spectrometer, which has a much larger area (Rau et al 2004(Rau et al , 2005 1 The SPI-ACS shield is one of the most sensitive all-sky monitors in the history of gamma-ray burst observations. Thanks to the highly elliptical orbit of INTEGRAL (Eismont et al 2003) with a period of 72 hours (64.8 hours after 2015), there are almost no zones for it shaded by the Earth (coverage is ∼ > 80% of the sky), while a stable background on a time scale of hundreds or even thousands of seconds allows it to effectively carry out a sub-threshold search for transients of different durations.…”

Section: Acs Shield Of the Spi Gamma-ray Spectrometermentioning

confidence: 99%

Наблюдение в гамма-диапазоне второго связанного со слиянием нейтронных звезд события LIGO/Virgo S190425z

Pozanenko

Minaev²,

Гребенев³

et al. 2019

Письма в Астрон. ж.

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Observations of the gravitational-wave (GW) event S190425z registered by the LIGO/Virgo detectors with the Anti-Coincidence Shield (ACS) of the gamma-ray spectrometer SPI aboard the INTEGRAL observatory are presented. With a high probability (> 99%) it was associated with a neutron star merger in a close binary system. This is only the second event of such type in the history of gravitational-wave observations (after GW 170817). A weak gamma-ray burst, GRB 190425, consisting of two pulses in ∼ 0.5 and ∼ 5.9 s after the moment of merging the stars in S190425z was detected by SPI-ACS. The pulses had a priori reliability of 3.5σ and 4.4 σ as single events and 5.5σ as a combined event. Analysis of the SPI-ACS count rate history recorded these days (∼ 125 ks observations in total) has shown that the rate of the appearance of two close pulses with characteristics of GRB 190425 by chance does not exceed 6.4 × 10 −5 s −1 (that is, by chance such events occur on average every ∼ 4.3 hours). We note that the time profile of the gamma-ray burst GRB 190425 has a lot in common with the profile of the gamma-ray burst GRB 170817A accompanying the GW 170817 event; that both the mergers of neutron stars were the closest ( ∼ < 150 Mpc) of all the events registered by the LIGO/Virgo detectors; and that there were no confident excesses of gamma-ray emission over the background detected in any of ∼ 30 black hole merger events recorded to the moment by these detectors. No hard X-ray flares were detected in the field of view of the SPI and IBIS-ISGRI gamma-ray telescopes aboard INTEGRAL. This, as well as the lack of detection of gamma-ray emission from GRB 190425 by the GBM gamma-ray burst monitor of the Fermi observatory assuming its occultation by the Earth, can significantly reduce the localization area for the source of this gravitational-wave event. The estimates of the parameters Eiso and Ep for the gamma-ray burst GRB 190425 are obtained and compared with the similar parameters for the GRB 170817A burst.

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The Radio and X-ray Mode-Switching Pulsar PSR B0943+10

Cited by 6 publications

References 49 publications

PSR B0943+10: low-frequency study of subpulse periodicity in the Bright mode with LOFAR

PSR B0943+10: low-frequency study of subpulse periodicity in the Bright mode with LOFAR

Thermal Emission and Magnetic Beaming in the Radio and X-Ray Mode-switching PSR B0943+10

Наблюдение в гамма-диапазоне второго связанного со слиянием нейтронных звезд события LIGO/Virgo S190425z

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