Apsidal motion in 4U 0115+63 and orbital parameters of 2S 1417−624 and V0332+53

Raichur, Harsha; Paul, Biswajit

doi:10.1111/j.1365-2966.2010.16862.x

Cited by 39 publications

(38 citation statements)

References 36 publications

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“…The 1-day sensitivity (for 15-50 keV) of the BAT is 5.3 mCrab (∼7 × 10 −11 erg cm −2 s −1 ; Krimm et al 2013), limiting the peak brightness of these episodes to LX 4 × 10 35 erg s −1 (assuming a distance of 7 kpc for both sources). Those rebrightening events occurred at times of periastron passage of the neutron star (based on the ephemerides of Doroshenko et al (2015b) and Raichur & Paul (2010); dotted lines in Figure 1). Therefore, these are likely related to type-I outbursts, albeit much fainter.…”

Section: Observations Analysis and Resultsmentioning

confidence: 99%

Meta-stable low-level accretion rate states or neutron star crust cooling in the Be/X-ray transients V0332+53 and 4U 0115+63

Wijnands

Degenaar

2016

Monthly Notices of the Royal Astronomical Society: Letters

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The Be/X-ray transients V0332+53 and 4U 0115+63 exhibited giant, type-II outbursts in 2015. Here we present Swift/XRT follow-up observations at the end of those outbursts. Surprisingly, the sources did not decay back to their known quiescent levels but stalled at a (slowly decaying) meta-stable state with luminosities a factor ∼10 above that observed in quiescence. The spectra in these states are considerably softer than the outburst spectra and appear to soften in time when the luminosity decreases. The physical mechanism behind these metastable states is unclear and they could be due to low-level accretion (either directly onto the neutron stars or onto their magnetospheres) or due to cooling of the accretion-heated neutron star crusts. Based on the spectra, the slowly decreasing luminosities, and the spectral softening, we favour the crust cooling hypothesis but we cannot exclude the accretion scenarios. On top of this meta-stable state, weak accretion events were observed that occurred at periastron passage and may thus be related to regular type-I outbursts.

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Section: Observations Analysis and Resultsmentioning

confidence: 99%

Meta-stable low-level accretion rate states or neutron star crust cooling in the Be/X-ray transients V0332+53 and 4U 0115+63

Wijnands

Degenaar

2016

Monthly Notices of the Royal Astronomical Society: Letters

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“…We emphasize that both the orbital modulation and the intrinsic variation of the pulsar spin frequency must be modeled. The intrinsic spin evolution of V 0332+53 during an outburst is rather complicated, as found by Zhang et al (2005) and Raichur & Paul (2010), who had to include the second pulse period derivative to describe it adequately. In fact, this is expected because the accretion torque exserted onto the neutron star depends on the accretion rate, which changes dramatically during the outburst.…”

Section: Data Analysis and Resultsmentioning

confidence: 99%

“…Later Zhang et al (2005) and Raichur & Paul (2010) used Rossi X-Ray Timing Explorer (RXTE) and International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations performed during the 2004−2005 giant outburst to refine the orbital solution. These authors found a significantly higher projected semimajor axis a sin i value than reported by Stella et al (1985), which was associated with apsidal motion in the system.…”

Section: Introductionmentioning

confidence: 99%

Orbital parameters of V 0332+53 from 2015 giant outburst data

Doroshenko

Tsygankov

Santangelo

2016

A&A

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We present the updated orbital solution for the transient Be X-ray binary V 0332+53, which we obtained by complementing historical measurements with the data from the gamma-ray burst monitor onboard Fermi. These were acquired during the outburst in JuneOctober 2015. We modeled the observed changes in the spin-frequency of the pulsar and deduced the orbital parameters of the system. We significantly improved existing constrains and show that contrary to previous findings, no change in orbital parameters is required to explain the spin evolution of the source during the outbursts in 1983, 2005, and 2015. The reconstructed intrinsic spin-up of the neutron star during the latest outburst is found to be comparable with previously observed values and predictions of the accretion torque theory.

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“…The rate at which the longitude of periastron of an eccentric orbit advances can be related to the absidal motion constant, which depends on the model of the mass distribution inside the star (Kopal 1978;Batten 1973). X-ray pulsars in HMXBs have frequently been considered the most promising laboratories for accurately measuring the apsidal advance (see also Raichur & Paul 2010a, for the case of 4U0115+63). The neutron star in these systems can be well approximated as a point source with a negligible absidal motion constant with respect to that of the massive companion.…”

Section: Apsidal Motionmentioning

confidence: 99%

Ephemeris, orbital decay, and masses of ten eclipsing high-mass X-ray binaries

Falanga

Bozzo

Lutovinov

et al. 2015

A&A

189

265

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We update the ephemeris of the eclipsing high-mass X-ray binary (HMXB) systems LMC X-4, Cen X-3, 4U 1700-377, 4U 1538-522, SMC X-1, IGR J18027-2016, Vela X-1,IGR J17252-3616, XTE J1855-026, and OAO 1657-415 with the help of more than ten years of monitoring these sources with the All Sky Monitor onboard RXTE and with the Integral Soft Gamma-Ray Imager onboard INTEGRAL. These results are used to refine previous measurements of the orbital period decay of all sources (where available) and provide the first accurate values of the apsidal advance in Vela X-1 and 4U 1538-522. Updated values for the masses of the neutron stars hosted in the ten HMXBs are also provided, as well as the long-term light curves folded on the best determined orbital parameters of the sources. These light curves reveal complex eclipse ingresses and egresses that are understood mostly as being caused by accretion wakes. Our results constitute a database to be used for population and evolutionary studies of HMXBs and for theoretical modeling of long-term accretion in wind-fed X-ray binaries.

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Apsidal motion in 4U 0115+63 and orbital parameters of 2S 1417−624 and V0332+53

Cited by 39 publications

References 36 publications

Meta-stable low-level accretion rate states or neutron star crust cooling in the Be/X-ray transients V0332+53 and 4U 0115+63

Meta-stable low-level accretion rate states or neutron star crust cooling in the Be/X-ray transients V0332+53 and 4U 0115+63

Orbital parameters of V 0332+53 from 2015 giant outburst data

Ephemeris, orbital decay, and masses of ten eclipsing high-mass X-ray binaries

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