The X-Ray Transient XTE J1118+480: Multiwavelength Observations of a Low-State Minioutburst

We present multiwavelength observations of the newly discovered X-raytransient XTE J1118+480 obtained in the rising phase of the 2000 Apriloutburst. This source is located at unusually high Galactic latitude and in avery low absorption line of sight. This made the first EUVE spectroscopy of anX-ray transient outburst possible. Together with our HST, RXTE, and UKIRT datathis gives unprecedented spectral coverage. We find the source in the low hardstate. The flat IR-UV spectrum appears to be a combination of optically thickdisk emission and flat spectrum emission, possibly synchrotron, while at higherenergies, including EUV, a typical low hard state power-law is seen. EUVEobservations reveal no periodic modulation, suggesting an inclination lowenough that no obscuration by the disk rim occurs. We discuss the nature of thesource and this outburst and conclude that it may be more akin tomini-outbursts seen in GRO J0422+32 than to a normal X-ray transient outburst.Comment: 4 pages, 3 figures, replaced with accepted version. Uses emulateapj5.st