JEM-X observations of the Be/X-ray binary EXO 2030+375

We have used data from the Joint European Monitor (JEM-X) to perform an X-ray spectral and timing analysis of the 42-s transient pulsar EXO 2030+375 during an X-ray outburst. X-ray pulsations are clearly detected with an average pulse period of 41.66(plus-minus)0.05 s and an average pulse fraction of 60%. The profile of the energy spectrum did not change appreciably throughout the X-ray outburst, although the source shows a slightly softer spectrum during periastron passage in the energy range 9-25 keV. The 5-25 keV X-ray luminosity changed by a factor of 2 throughout the observations, reaching a maximum value of 3*10^36 erg s^ -1. These observations allowed us to verify the in-flight instrumental properties of the JEM-X Monitor.