We report the first direct X-ray evidence that an AGN is hidden in the center of IRAS12393+3520 .
An ASCA observation of this target unveiled a bright ( 0.5–10 keV luminosity 3.9 \times 10 ^ { 42 } erg s ^ { -1 } ) and variable source , with minimum observed doubling/halving time scale comprised in the range 30–75 ks .
A model composed by a simple power-law , with photon index \simeq 1.8 and an absorption edge , whose threshold energy is consistent with K-shell photoionization of O vii , provides an adequate fit of the spectrum .
This suggests that we are observing the emission from the nuclear region through a warm absorber of { N _ { H } \simeq } a few 10 ^ { 21 } cm ^ { -2 } .
If it has internal dust with Galactic gas-to-dust ratio , it could explain the lack of broad H _ { \beta } emission , even in the episodic presence of a broad H _ { \alpha } emission line .
Optical spectra obtained over several years show indeed variations in the strength of this broad H _ { \alpha } component .
A distribution of dusty , optically thick matter on spatial scales a few hundreds parsec , which does not intercept the line of sight towards the nucleus , is probably required to account simultaneously for the relative [ OIII ] luminosity deficit in comparison to the X-rays .
The high IR to X-ray luminosity ratio is most likely due to intense star formation in the circumnuclear region .
IRAS12393+3520 might thus exhibit simultaneously nuclear activity and remarkable star formation .