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arXiv · astro-ph/0103051

Complete and Simultaneous Spectral Observations of the Black-Hole X-ray Nova XTE J1118+480

Abstract

The X-ray nova XTE J1118+480 suffers minimal extinction (b = 62 degrees) and therefore represents an outstanding opportunity for multiwavelength studies. Hynes et al. (2000) conducted the first such study, which was centered on 2000 April 8 using UKIRT, EUVE, HST and RXTE. On 2000 April 18, the Chandra X-ray Observatory obtained data coincident with a second set of observations using all of these same observatories. A 30 ks grating observation using Chandra yielded a spectrum with high resolution and sensitivity covering the range 0.24-7 keV. Our near-simultaneous observations cover approximately 80% of the electromagnetic spectrum from the infrared to hard X-rays. The UV/X-ray spectrum of XTE J1118+480 consists of two principal components. The first of these is an approximately 24 eV thermal component which is due to an accretion disk with a large inner disk radius: > 35 Schwarzschild radii. The second is a quasi power-law component that was recorded with complete spectral coverage from 0.4-160 keV. A model for this two-component spectrum is presented in a companion paper by Esin et al. (2001).

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J. E. McClintock, C. A. Haswell, M. R. Garcia, J. J. Drake, R. I. Hynes, H. L. Marshall, M. P. Muno, S. Chaty, P. M. Garnavich, P. J. Groot, W. H. G. Lewin, C. W. Mauche, J. M. Miller, G. G. Pooley, C. R. Shrader, S. D. Vrtilek. 2001-03-02. Complete and Simultaneous Spectral Observations of the Black-Hole X-ray Nova XTE J1118+480. https://doi.org/10.1086/321449

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