A0535+26 - Refined position measurement and new pulse period data

Li, F.; Clark, G. W.; Jernigan, J. G.; Rappaport, S.

doi:10.1086/156915

Cited by 28 publications

(13 citation statements)

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“…Complications arise when the reverse of the above condition obtains, and in such circumstances the orbits are difficult to measure. This is the case for slow X-ray pulsars (with their concomitantly large values of p) in long-period orbits (see, for example, Li et al 1979). An example of an orbital determination from a measurement of the Doppler delays of X-ray pulses is shown in Figure 7.…”

Section: Orbital Determinations and The Evaluation Of Binarymentioning

confidence: 94%

Neutron Stars in Interacting Binary Systems

Joss¹,

Rappaport²

1984

Annu. Rev. Astron. Astrophys.

253

134

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Section: Orbital Determinations and The Evaluation Of Binarymentioning

confidence: 94%

Neutron Stars in Interacting Binary Systems

Joss¹,

Rappaport²

1984

Annu. Rev. Astron. Astrophys.

253

134

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“…Among them are Rosenberg et al (1975), Fishman & Watts (1977), Bradt et al (1976), Li et al (1979), Hameury et al (1983), Frontera et al (1985), Nagase et al (1982), Sembay et al (1990), Motch et al (1991), Coe et al (1990), Makino (1989), Sunyaev & Titarchuk (1989), Cusumano et al (1992), and Finger et al (1994and Finger et al ( , 2006and Finger et al ( , 2009a.…”

Section: Long-term Pulse Frequency Evolutionmentioning

confidence: 99%

X-Ray and Optical Observations of a 0535+26

Camero-Arranz

Finger

Wilson-Hodge

et al. 2012

ApJ

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We present recent contemporaneous X-ray and optical observations of the Be/X-ray binary system A 0535+26 with the Fermi/Gamma-ray Burst Monitor (GBM) and several ground-based observatories. These new observations are put into the context of the rich historical data (since ∼1978) and discussed in terms of the neutron-star-Be-disk interaction. The Be circumstellar disk was exceptionally large just before the 2009 December giant outburst, which may explain the origin of the unusual recent X-ray activity of this source. We found a peculiar evolution of the pulse profile during this giant outburst, with the two main components evolving in opposite ways with energy. A hard 30-70 mHz X-ray quasi-periodic oscillation was detected with GBM during this 2009 December giant outburst. It becomes stronger with increasing energy and disappears at energies below 25 keV. In the long term a strong optical/X-ray correlation was found for this system, however in the medium term the Hα equivalent width and the V-band brightness showed an anti-correlation after ∼2002 August. Each giant X-ray outburst occurred during a decline phase of the optical brightness, while the Hα showed a strong emission. In late 2010 and before the 2011 February outburst, rapid V /R variations are observed in the strength of the two peaks of the Hα line. These had a period of ∼25 days and we suggest the presence of a global one-armed oscillation to explain this scenario. A general pattern might be inferred, where the disk becomes weaker and shows V /R variability beginning ∼6 months following a giant outburst.

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“…Its optical companion HDE 245770 (Li et al 1979) is a B0IIIe star with an estimated distance of ∼2 kpc (Steele et al 1998). This distance estimate has been confirmed by the first Gaia data release, which also reports a parallax corresponding to a distance of ∼2 kpc 1 (Gaia Collaboration et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Looking at A 0535+26 at low luminosities with NuSTAR

Ballhausen

Pottschmidt

Fürst

et al. 2017

A&A

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We report on two NuSTAR observations of the high-mass X-ray binary A 0535+26 taken toward the end of its normal 2015 outburst at very low 3-50 keV luminosities of ∼1.4 × 10 36 erg s −1 and ∼5 × 10 35 erg s −1 , which are complemented by nine Swift observations. The data clearly confirm indications seen in earlier data that the source's spectral shape softens as it becomes fainter. The smooth, exponential rollover at high energies present in the first observation evolves to a much more abrupt steepening of the spectrum at 20-30 keV. The continuum evolution can be well described with emission from a magnetized accretion column, modeled using the compmag model modified by an additional Gaussian emission component for the fainter observation. Between the two observations, the optical depth changes from 0.75 ± 0.04 to 0.56−0.04 , the electron temperature remains constant, and there is an indication that the column decreases in radius. Since the energy resolved pulse profiles remain virtually unchanged in shape between the two observations, the emission properties of the accretion column, however, reflect the same accretion regime. This conclusion is also confirmed by our result that the energy of the cyclotron resonant scattering feature (CRSF) at ∼45 keV is independent of the luminosity, implying that the magnetic field in the region in which the observed radiation is produced is the same in both observations. Finally, we also constrain the evolution of the continuum parameters with rotational phase of the neutron star. The width of the CRSF could only be constrained for the brighter observation. Based on Monte-Carlo simulations of CRSF formation in single accretion columns, its pulse phase dependence supports a simplified fan beam emission pattern. The evolution of the CRSF width is very similar to that of the CRSF depth, which is, however, in disagreement with expectations.

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A0535+26 - Refined position measurement and new pulse period data

Cited by 28 publications

References 0 publications

Neutron Stars in Interacting Binary Systems

Neutron Stars in Interacting Binary Systems

X-Ray and Optical Observations of a 0535+26

Looking at A 0535+26 at low luminosities with NuSTAR

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