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Related papers: INTEGRAL observations of Her X-1

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We present the first results of the observations of the X-ray pulsars LMC X-4, 4U0352+309 and EXO1722-363 performed with the INTEGRAL observatory. The LMC X-4 was investigated during the whole superorbital cycle ($\sim$30 days) and it was…

We report the first INTEGRAL timing and spectral analysis of the high mass X-ray binary source 2S 0114+65 at high energies (5-100 keV). The pulse period was found at 2.668 hr with a high pulsed fraction, ~80% in both the 20-40 keV and 40-80…

Astrophysics · Physics 2009-11-11 E. W. Bonning , M. Falanga

We present the results of ten years of repeated measurements of the Cyclotron Resonance Scattering Feature (CRSF) in the spectrum of the binary X-ray pulsar Her X-1 and report the discovery of a positive correlation of the centroid energy…

Astrophysics · Physics 2009-11-13 R. Staubert , N. I. Shakura , K. Postnov , J. Wilms , R. E. Rothschild , W. Coburn , L. Rodina , D. Klochkov

We present a broad-band X-ray timing study of the variations in pulse behavior with superorbital cycle in the low-mass X-ray binary Her X-1. This source shows a 35-day superorbital modulation in X-ray flux that is likely caused by…

The accreting X-ray pulsar Her X-1 shows two types of long-term variations, both with periods of ~35 days: 1) Turn-on cycles, a modulation of the flux}, with a ten-day long Main-On and a five-day long Short-On, separated by two Off-states,…

High Energy Astrophysical Phenomena · Physics 2015-06-12 R. Staubert , D. Klochkov , D. Vasco , K. Postnov , N. Shakura , J. Wilms , R. E. Rothschild

We present detailed spectral and temporal characteristics over the whole X-ray band. For this purpose data have been used from INTEGRAL, RXTE and XMM-Newton. The INTEGRAL hard X-ray (>10 keV) time-averaged total spectrum, can be described…

Astrophysics · Physics 2009-11-13 P. R. den Hartog , L. Kuiper , W. Hermsen

An overview of the results of observations for the transient X-ray pulsar 4U 0115+63, a member of a binary system with a Be star, since its discovery to the present day (~40 years) based on data from more than dozen observatories and…

High Energy Astrophysical Phenomena · Physics 2015-06-16 P. A. Boldin , S. S. Tsygankov , A. A. Lutovinov

We analyze the observations of the transient X-ray pulsar 4U 0115+63 with the RXTE and INTEGRAL observatories in a wide X-ray (3-100 keV) energy band during its intense outbursts in 1999 and 2004. The energy of the fundamental harmonic of…

Astrophysics · Physics 2009-06-23 S. S. Tsygankov , A. A. Lutovinov , E. M. Churazov , R. A. Sunyaev

Monitoring of pulse period variations in accreting binary pulsars is an important tool to study the interaction between the magnetosphere of the neutron star and the accretion disk. While the X-ray flux of the brightest X-ray pulsars have…

High Energy Astrophysical Phenomena · Physics 2010-01-29 D. Klochkov , R. Staubert , K. Postnov , N. Shakura , A. Santangelo

I review the properties of three X-ray accreting millisecond pulsars observed with INTEGRAL. Out of seven recently discovered accretion-powered pulsars (one discovered by INTEGRAL), three were observed with the INTEGRAL satellite up to 300…

Astrophysics · Physics 2007-11-07 Maurizio Falanga

Recent observations of Her X-1 with NuSTAR and INTEGRAL in 2016 have provided evidence that the 20-year decay of the cyclotron line energy found between 1996 and 2015 has ended and that an inversion with a new increase, possibly similar to…

High Energy Astrophysical Phenomena · Physics 2017-11-08 R. Staubert , D. Klochkov , F. Fürst , J. Wilms , R. E. Rothschild , F. Harrison

The cyclotron line feature in the X-ray spectrum of the accretion powered pulsar Her X-1 has been observed and monitored for over three decades. The line energy exhibited a slow secular decline over the period 1995-2014, with a possible…

High Energy Astrophysical Phenomena · Physics 2020-07-15 S. Bala , D. Bhattacharya , R. Staubert , C. Maitra

During the last 10 years, INTEGRAL made a unique contribution to the study of accreting millisecond X-ray pulsars (AMXPs), discovering three of the 14 sources now known of this class. Besides increasing the number of known AMXPs, INTEGRAL…

High Energy Astrophysical Phenomena · Physics 2013-02-13 M. Falanga , L. Kuiper , J. Poutanen , D. K. Galloway , E. Bozzo , A. Goldwurm , W. Hermsen , L. Stella

We report on the results of the longest uninterrupted observation of the Anomalous X-ray Pulsar 1RXS J1708-4009 obtained with the BeppoSAX satellite in August 2001. In the phase-resolved spectrum, corresponding to the rising part of the…

Astrophysics · Physics 2009-11-10 Nanda Rea , Gian Luca Israel , Luigi Stella

We conduct a comprehensive analysis of the accreting X-ray pulsar, Hercules X-1, utilizing data from IXPE and NuSTAR. IXPE performed five observations of Her X-1, consisting of three in the Main-on state and two in the Short-on state. Our…

We report on observations of the X-ray pulsar IGR J16320-4751 (a.k.a. AX J1631.9-4752) performed simultaneously with INTEGRAL and XMM-Newton. We refine the source position and identify the most likely infrared counterpart. Our simultaneous…

We report on our analysis of a large sample of energy dependent pulse profiles of the X-ray binary pulsar Hercules X-1. We find that all data are compatible with the assumption of a slightly distorted magnetic dipole field as sole cause of…

Astrophysics · Physics 2009-10-31 S. Blum , U. Kraus

We present an update of the orbital ephemeris of the binary X-ray pulsar Her X-1 and determine an improved value for the rate of orbital decay. In addition, we report the first measurement of the orbital eccentricity. We have analyzed pulse…

High Energy Astrophysical Phenomena · Physics 2015-05-13 R. Staubert , D. Klochkov , J. Wilms

Vela X-1 is a well-studied accreting X-ray pulsar, with a distinctive pulse profile that has been found to be very similar in different observations spread out over decades. On the other hand, significant variations down to the timescale of…

A great deal of emphasis on timing in the RXTE era has been on pushing toward higher and higher frequency phenomena, particularly kHz QPOs. However, the large areas of the RXTE pointed instruments provide another capability which is key for…