X-Ray Intensities and Spectra from Several Cosmic Sources

Chodil, G.; Mark, Hans; Rodrigues, R.; Seward, F. D.; Swift, C. D.

doi:10.1086/149312

Cited by 53 publications

(28 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Vela X-1: An eclipsing high-mass X-ray binary discovered in the early years of X-ray astronomy by Chodil et al (1967), this source is considered as an archetypal wind accretor. It is a persistent source with essentially random flux variations explained by accretion from a dense, structured wind surrounding the optical companion HD 77581(e.g., Fürst et al 2014b).…”

Section: Individual Sourcesmentioning

confidence: 99%

Cyclotron lines in highly magnetized neutron stars

Staubert

Trümper

Kendziorra

et al. 2019

A&A

244

221

View full text Add to dashboard Cite

Cyclotron lines, also called cyclotron resonant scattering features (CRSF) are spectral features, generally appearing in absorption, in the X-ray spectra of objects containing highly magnetized neutron stars, allowing the direct measurement of the magnetic field strength in these objects. Cyclotron features are thought to be due to resonant scattering of photons by electrons in the strong magnetic fields. The main content of this contribution focusses on electron cyclotron lines as found in accreting X-ray binary pulsars (XRBP) with magnetic fields on the order of several 10 12 Gauss. Also, possible proton cyclotron lines from single neutron stars with even stronger magnetic fields are briefly discussed. With regard to electron cyclotron lines, we present an updated list of XRBPs that show evidence of such absorption lines. The first such line was discovered in a 1976 balloon observation of the accreting binary pulsar Hercules X-1, it is considered to be the first direct measurement of the magnetic field of a neutron star. As of today (mid 2018), we list 36 XRBPs showing evidence of one ore more electron cyclotron absorption line(s). A few have been measured only once and must be confirmed (several more objects are listed as candidates). In addition to the Tables of objects, we summarize the evidence of variability of the cyclotron line as a function of various parameters (especially pulse phase, luminosity and time), and add a discussion of the different observed phenomena and associated attempts of theoretical modeling. We also discuss our understanding of the underlying physics of accretion onto highly magnetized neutron stars. For proton cyclotron lines, we present tables with seven neutron stars and discuss their nature and the physics in these objects.

show abstract

Section: Individual Sourcesmentioning

confidence: 99%

Cyclotron lines in highly magnetized neutron stars

Staubert

Trümper

Kendziorra

et al. 2019

A&A

244

221

View full text Add to dashboard Cite

show abstract

“…Vela X-1 is an eclipsing high-mass X-ray binary discovered in 1967 (Chodil et al 1967) at a distance of ∼2 kpc (Nagase 1989). It consists of the early type supergiant HD 77581 (B0.5Iab, R ∼ 34 R ) and a neutron star of ∼1.77 M (Rawls et al 2011), orbiting its companion with a period of 8.964 days.…”

Section: Introductionmentioning

confidence: 99%

The accretion environment in Vela X-1 during a flaring period usingXMM-Newton

Martínez-Núñez

Torrejón

Kühnel

et al. 2014

A&A

View full text Add to dashboard Cite

We present analysis of 100 ks contiguous XMM-Newton data of the prototypical wind accretor Vela X-1. The observation covered eclipse egress between orbital phases 0.134 and 0.265, during which a giant flare took place, enabling us to study the spectral properties both outside and during the flare. This giant flare with a peak luminosity of 3.92 +0.42 −0.09 × 10 37 erg s −1 allows estimates of the physical parameters of the accreted structure with a mass of ∼10 21 g. We have been able to model several contributions to the observed spectrum with a phenomenological model formed by three absorbed power laws plus three emission lines. After analysing the variations with orbital phase of the column density of each component, as well as those in the Fe and Ni fluorescence lines, we provide a physical interpretation for each spectral component. Meanwhile, the first two components are two aspects of the principal accretion component from the surface of the neutron star, the third component seems to be the X-ray light echo formed in the stellar wind of the companion.

show abstract

“…Since then it has been studied extensively from balloons at UCSD. The spectrum obtained from our work together with certain other results at higher (Haymes et al, 1968a) and lower energies (Chodil et al, 1967) are shown in Figure 4. There are also many additional observations, all of which are in general agreement with the spectrum in Figure 4.…”

Section: The Crab Nebulamentioning

confidence: 52%

Properties of individual X-ray sources: (Invited discourse)

Peterson

1970

Symp. - Int. Astron. Union

View full text Add to dashboard Cite

Abstract. Observations to determine the spectra and time variations of hard X-rays from cosmic sources have been made from balloons and from the OSO-III satellite. These data have been obtained using actively collimated scintillation counters with apertures between 6 and 24° FWHM, areas between 10 and 50 cm 2 and which operate over the 10-300 keV range. The Crab Nebula has been observed on three occasions over a 22-month period between September 1965 and July 1967. The power law spectrum has a number index of 2.0 ± 0.1. No long-term changes were observed over the 30-100keV range with a limit at 3%/yr. A balloon search with a 10 cm 2 Ge(Li) detector for X-ray lines at 62.5 keV, 110 keV and 180 keV due to heavy element radioactive decays which would be produced in the initial Crab explosion based on the Cf 254 hypothesis has resulted in upper limits at about 10" 3 y-rays cm 2 -sec. This is about a factor of 20 above the predicted levels. Simultaneous X-ray and optical observations of SCO XR-1 from OSO-III confirm that X-ray and optical flaring are indeed coincident phenomena, and that although the X-ray intensity increases about a factor of two during the flare, the equivalent temperature of the excess radiation is nearly the same as that of the quiescent object. Upper limits, 95% confidence, on the flux of M-87 at 40 keV have been obtained. These are inconsistent with the flux of 1.2 x 10~4 photons/cm 2 -sec-keV reported in the literature. CYG X-l has been observed to have a power law of number index 2.0 ± 0.2. The OSO-III has observed a number of sources in the southern skies including NOR XR-2 and the variable source Centaurus XR-2.

show abstract

X-Ray Intensities and Spectra from Several Cosmic Sources

Cited by 53 publications

References 0 publications

Cyclotron lines in highly magnetized neutron stars

Cyclotron lines in highly magnetized neutron stars

The accretion environment in Vela X-1 during a flaring period usingXMM-Newton

Properties of individual X-ray sources: (Invited discourse)

Contact Info

Product

Resources

About