The X-ray nova XTE J1118 + 480 suffers minimal extinction (b = 62°) and therefore represents an outstanding opportunity for multiwavelength studies. Hynes et al. 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 ≈ 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 ≈ 24 eV thermal component that is caused by an accretion disk with a large inner disk radius: ≳ 35RSchw. The second is a quasi power-law component that was recorded with complete spectral coverage from 0.4 to 160 keV. A model for this two-component spectrum is presented in a companion paper by Esin et al.
Publication Source (Journal or Book title)
McClintock, J., Haswell, C., Garcia, M., Drake, J., Hynes, R., Marshall, H., Muno, M., Chaty, S., Garnavich, P., Groot, P., Lewin, W., Mauche, C., Miller, J., Pooley, G., Shrader, C., & Vrtilek, S. (2001). Complete and simultaneous spectral observations of the black hole X-ray nova XTE J1118 + 480. Astrophysical Journal, 555 (1 PART 1), 477-482. https://doi.org/10.1086/321449