Letter to the Editor

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

¹ GACE, Instituto de Ciencias de los Materiales, Universidad de Valencia, PO Box 20085, 46071 Valencia, Spain
² Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, 85748 Garching, Germany
³ INTEGRAL Science Data Centre, Chemin d'Écogia 16, 1290 Versoix, Switzerland
⁴ Danish Space Research Institute, Juliane Maries Vej 30, 2100, Copenhagen, Denmark

Corresponding author: S. Martínez Núñez, silvia.martinez@uv.es

Received: 7 July 2003
Accepted: 1 August 2003

Abstract

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 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  erg s^-1. These observations allowed us to verify the in-flight instrumental properties of the JEM-X Monitor.