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Author An, Hongjun ♦ Romani, Roger W.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ BEAMS ♦ BINARY STARS ♦ COSMIC GAMMA SOURCES ♦ EMISSION ♦ ENERGY SPECTRA ♦ GAMMA RADIATION ♦ GEV RANGE ♦ LIMITING VALUES ♦ MODULATION ♦ PLASMA ♦ PULSARS ♦ RELATIVISTIC RANGE ♦ SIMULATION ♦ STARS ♦ STELLAR WINDS ♦ TEV RANGE ♦ VISIBLE RADIATION
Abstract We present broadband spectral energy distributions and light curves of the gamma-ray binary 1FGL J1018.6−5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is similar to that in the X-ray band, suggesting a common spectral component. However, above a GeV the orbital light curve changes significantly. We suggest that the GeV band contains significant flux from a pulsar magnetosphere, while the X-ray to TeV light curves are dominated by synchrotron and Compton emission from an intrabinary shock (IBS). We find that a simple one-zone model is inadequate to explain the IBS emission, but that beamed Synchrotron-self Compton radiation from adiabatically accelerated plasma in the shocked pulsar wind can reproduce the complex multiband light curves, including the variable X-ray spike coincident with the gamma-ray maximum. The model requires an inclination of ∼50° and an orbital eccentricity of ∼0.35, consistent with the limited constraints from existing optical observations. This picture motivates searches for pulsations from the energetic young pulsar powering the wind shock.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-04-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 838
Issue Number 2


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