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The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays

P. R. den Hartog·L. Kuiper·W. Hermsen·N. Rea·M. Durant·B. Stappers·V. M. Kaspi·R. Dib
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Abstract

For the first time a quasi-simultaneous multi-wavelength campaign has been performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band. 4U 0142+61 was an INTEGRAL target for 1 Ms in July 2005. During these observations it was also observed in the X-ray band with Swift and RXTE, in the optical and NIR with Gemini North and in the radio with the WSRT. In this paper we present the source-energy distribution. The spectral results obtained in the individual wave bands do not connect smoothly; apparently components of different origin contribute to the total spectrum. Remarkable is that the INTEGRAL hard X-ray spectrum (power-law index 0.79 +/- 0.10) is now measured up to an energy of ~230 keV with no indication of a spectral break. Extrapolation of the INTEGRAL power-law spectrum to lower energies passes orders of magnitude underneath the NIR and optical fluxes, as well as the low ~30 microJy (2 sigma) upper limit in the radio band.

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P. R. den Hartog, L. Kuiper, W. Hermsen, N. Rea, M. Durant, B. Stappers, V. M. Kaspi, R. Dib. 2006-11-06. The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays. https://doi.org/10.1007/s10509-007-9367-1

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