Unusual quiescent X-ray activity from XTE J0421+560 (CI Cam)
  We report on BeppoSAX observations of the X-ray transient XTE J0421+560 in quiescence 156, 541, and ~690 days after the maximum of the 1998 April outburst. In the first observation the source was soft with a power-law photon index of 4.0 (+1.9 -0.9) and absorption, NH, of (1.1 +4.9 -1.1) X 10^21 atom/cm2. In the second observation, the source brightened by a factor ~15 in the 1-10 keV energy range, became significantly harder with a photon index of 1.86 (+0.27 -0.32) and was strongly absorbed with NH = (4.0 +/- 0.8) X 10^23 atom/cm2. There is evidence for a narrow emission line in both spectra at \~7 keV. In the third observation, the source had faded by a factor ~$8 from the previous observation to below the BeppoSAX detection level. It is possible that these variations result from orbital motion of a compact object around the B[e] star companion with the intense, absorbed, spectrum arising during passage through dense circumstellar material. If this is the case, the system may be continuing to exhibit periodic activity. 
A.N. Parmar (1), T. Belloni (2), M. Orlandini (3), D. Dal Fiume (3),   A. Orr (1), N. Masetti (3) ((1) ESA/ESTEC, (2) Obs Br...