Using the 1 Ms Chandra Deep Field North and 15 \mu m ISOCAM HDF-N surveys we find a tight correlation between the population of strongly evolving starbursts discovered in faint 15 \mu m ISOCAM surveys and the apparently normal galaxy population detected in deep X-ray surveys .
Up to 100 % of the X-ray detected emission-line galaxies ( ELGs ) have 15 \mu m counterparts , in contrast to 10–20 % of the X-ray detected absorption-line galaxies and AGN-dominated sources .
None of the X-ray detected ELGs is detected in the hard band ( 2–8 keV ) , and their stacked-average X-ray spectral slope of \Gamma \approx 2.0 suggests a low fraction of obscured AGN activity within the X-ray detected ELG population .
The characteristics of the z = 0.4–1.3 X-ray detected ELGs are consistent with those expected for M82 and NGC 3256-type starbursts ; these X-ray detected ELGs contribute \approx 2 % of the 0.5–8.0 keV X-ray background .
The only statistical difference between the X-ray detected and X-ray undetected 15 \mu m selected ELGs is that a much larger fraction of the former have radio emission .