Evidence of an irradiated accretion disc in XTE J1818-245

The X-ray transient source XTE J1818-245 went through an outburst in 2005 that was observed during a multi-wavelength campaign from radio to soft γ-rays. We performed new optical observations with the ESO/NTT telescope at La Silla. The broad-band spectral energy distribution revealed that the outer parts of the accretion disc had to be irradiated by its inner parts to explain the optical emission.