Triptychon

Haberl, Franz P.; Frisch, Max

doi:10.2307/40133671

Cited by 5 publications

(9 citation statements)

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“… Secular variability of the X Persei pulse period as historically observed by Nagase (1989), Lutovinov et al (1994), Haberl (1994), Robba et al (1996), Di Salvo et al (1998) and Delgado‐Marti et al (2001) (dark circles). The results of the RXTE , Integral and XMM–Newton measurements in this paper are shown by the triangles, open circles and dark squares, respectively.…”

Section: Resultsmentioning

confidence: 63%

Strong outburst activity of the X-ray pulsar X Persei during 2001-2011

Lutovinov

Tsygankov

Chernyakova

2012

Monthly Notices of the Royal Astronomical Society

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We present results of a comprehensive analysis of the X-ray pulsar X Persei over the period 1996 to 2011, encompassing the quite low state and subsequent strong outburst activity. Using data from the RXTE and Swift observatories we detected several consecutive outbursts, during which the source luminosity increased by a factor of ~5 up to L_x~1.2x10^{35} erg/s. Previously the source was observed in a high state only once. The source spectrum in a standard energy band (4-25 keV) is independent of the flux change and can be described by a model that includes both thermal and non-thermal components. With the help of the INTEGRAL observatory data we registered the highly significant cyclotron absorption line in the source spectrum and, for the first time, significantly detected a hard X-ray emission from the pulsar up to ~160 keV. We also report drastic changes of the pulse period during the outburst activity: a long episode of spin-down was changed to spin-up with a rate of Pdot/P = -(3-5)x10^{-4} yr^{-1}, that is several times higher than previous rates of spin-up and spin-down. To search for a correlation between the X-ray and optical lightcurves we took data from the AAVSO International Database. No significant correlation between optical and X-ray fluxes at any time lag from dozens of days to years was found.Comment: 8 pages, 6 figures, accepted for publication in MNRA

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Section: Resultsmentioning

confidence: 63%

Strong outburst activity of the X-ray pulsar X Persei during 2001-2011

Lutovinov

Tsygankov

Chernyakova

2012

Monthly Notices of the Royal Astronomical Society

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“…Both models aim to mimic characteristic features of a Comptonization spectrum, therefore we also attempted to use a true Comptonization model derived from first principles (Titarchuk 1994) with two components of independent temperatures and optical depths. In all cases photoelectric absorption was included with the column depth fixed to 2 × 10 21 atoms cm −2 (Haberl 1994;Di Salvo et al 1998) since INTEGRAL does not have the low-energy coverage required to constrain it. The results are summarized in Table 1 and Fig.…”

Section: Data and Analysismentioning

confidence: 99%

The hard X-ray emission of X Persei

Doroshenko

Santangelo

Kreykenbohm

et al. 2012

A&A

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We present an analysis of the spectral properties of the peculiar X-ray pulsar X Per based on INTEGRAL observations. We show that the source exhibits an unusually hard spectrum and is confidently detected by ISGRI up to more than 100 keV. We find that two distinct components may be identified in the broadband 4-200 keV spectrum of the source. We interpret these components as the result of thermal and bulk Comptonization in the vicinity of the neutron star and describe them with several semi-phenomenological models. The previously reported absorption feature at ∼30 keV is not required in the proposed scenario and therefore its physical interpretation must be taken with caution. We also investigated the timing properties of the source in the framework of existing torque theory, concluding that the observed phenomenology can be consistently explained if the magnetic field of the neutron star is ∼10 14 G.

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“…Furthermore, observations of X‐ray source in X Per show no evidence for a regular spin‐up of this pulsar. Instead, it exhibits apparent erratic pulse frequency variations on a time‐scale of a few days, which are superposed with a 10–20 yr spin‐up/spin‐down trends around the average period of 837 s (Haberl 1994; Delgado‐Marti et al 2001, and references therein). The transitions between the spin‐up and spin‐down stages occur without any significant variations of the system X‐ray luminosity and, therefore, cannot be associated with the transitions of the neutron star between the accretor and propeller states.…”

Section: Accretion Flow Geometrymentioning

confidence: 99%

The origin of long-period X-ray pulsars

Ikhsanov

2007

Monthly Notices of the Royal Astronomical Society

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Several relatively bright, persistent X-ray sources display regular pulses, with periods in the range of 700-10000 s. These sources are identified with massive close binaries in which a neutron star accretes material onto its surface. The observed pulsations in all of them, but one, are unambiguously associated with the spin period of the neutron star. Analyzing possible history of these pulsars I conclude that the neutron stars in these systems undergo spherical accretion and their evolutionary tracks in a previous epoch contained three instead of two states, namely, ejector, supersonic propeller, and subsonic propeller. An assumption about a supercritical value of the initial magnetic field of the neutron stars within this scenario is not necessary. Furthermore, I show that the scenario in which the neutron star in 2S 0114+650 is assumed to be a magnetar descendant encounters major difficulties in explaining the evolution of the massive companion. An alternative interpretation of the spin evolution of the neutron star in this system is presented and the problem raised by association of the 10000 s pulsations with the spin period of the neutron star is briefly discussed.Comment: 7 pages, 2 tables, accepted for publication in MNRA

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Triptychon

Cited by 5 publications

References 0 publications

Strong outburst activity of the X-ray pulsar X Persei during 2001-2011

Strong outburst activity of the X-ray pulsar X Persei during 2001-2011

The hard X-ray emission of X Persei

The origin of long-period X-ray pulsars

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