INTEGRAL and XMM-Newton spectral studies of NGC 4388

We present INTEGRAL and XMM-Newton observations of a Seyfert galaxy, the type 2 active galactic nucleus (AGN) NGC 4388. Several INTEGRAL observations performed in 2003 allow us to study the spectrum in the 20-300 keV range. In addition, two XMM-Newton observations give detailed insight into the 0.2-10 keV emission. The measurements presented here and comparison with previous observations by BeppoSAX, SIGMA, and Compton Gamma Ray Observatory (CGRO) OSSE show that the overall spectrum from soft X-rays up to the gamma-rays can be described by a highly absorbed (N(H)similar or equal to2.7x10(23) cm(-2)) and variable nonthermal component in addition to constant nonabsorbed thermal emission (Tsimilar or equal to0.8 keV) of low abundance (Zapproximate to0.07 Z(circle dot)), plus constant Fe Kalpha and Kbeta lines. The hard X-ray component is well described by a simple power law with a mean photon index of Gamma=1.7. During the INTEGRAL observations, the 20-100 keV flux increased by a factor of 1.4. The analysis of XMM-Newton data implies that the emission below 3 keV is decoupled from the AGN and probably due to extended emission as seen in Chandra observations. The constant iron line emission is apparently also decoupled from the direct emission of the central engine and likely to be generated in the obscuring material, e.g., in the molecular torus.