1998A&A...334L..73A

We report the detections of the hyperluminous galaxy IRAS F15307 +3252 at z=0.93 and of the Cloverleaf quasar, H 1413+117 at z=2.56, in the mid infrared using ISOCAM. The spectrum near 10µm (observed wavelength) joins smoothly with the data taken from the ground or with the IRAS satellite. We have detected none of the infrared features attributed to PAHs. For F15307 +3252, the mid-IR emission (9-16µm observed wavelength) is 8x10⁴⁵erg/s (q₀=0.5, H₀=75km/s/Mpc). This represents 10% of the total infrared emission from 5 to 200µm (7.5x10⁴⁶erg/s). The shape of the mid-IR spectrum can be fitted by the emission of warm dust grains at a temperature of about 400K. For the Cloverleaf QSO, H 1413+117, the grain temperature is even larger, ≃1000K. This intense near infrared emission can be used to put a lower limit on the size of the emitting regions of 5.7pc for F15307 +3252 and 5/sqrt((m))pc for the Cloverleaf where m is the magnification factor.