Extremely weak reflection features in the X-ray spectrum of XTE J1118+480: possible evidence for X-ray-emitting jets?

We have simultaneously fitted Chandra and RXTE spectra of the Galactic black hole XTE J1118+480 with three models for X-ray reflection. We explored a range of accretion disc ionizations (log xi = 1-4; xi = L-X/nR(2)) and iron abundances (0.10-1.00). Our fits with the constant-density ionized disc models of Ross & Fabian indicate that less than or equal to0.5 per cent (90 per cent confidence upper limit) of the observed flux is reflected. Fits with the PEXRAV model of Magdziarz & Zdziarski indicate that the two-dimensional solid angle (Omega/2pi) subtended by the disc relative to a central source of incident hard X-rays is 0.01 (+0.06)(-0.01). A combination of the high inclination (i = 81degrees), Comptonization, and bulk velocities may contribute to the low reflection fractions we have measured. The results are also consistent with extended jets being the source of the hard X-ray flux, as the disc would then represent a small solid angle as seen from the emission region.