Supernova 1994aj: a probe for pre-supernova evolution and mass-loss from the progenitor

Extensive photometric and spectroscopic observations of SN 1994aj until 540d after maximum light have been obtained. The photometry around maximum suggests that the SN belongs to the Type II Linear class, with a peak absolute magnitude of MV � 17.8 (assuming H0 = 75km s −1 Mpc −1 ). The spectra of SN 1994aj were unusual with the presence of a narrow line with a P-Cygni profile on the top of the broad Balmer line emission. This narrow feature is attributed to the presence of a dense superwind surrounding the SN. At 100-120 days after maximum light the SN ejecta starts to interact with this CSM. The SN luminosity decline rates slowed down (R = 0.46 mag (100d) −1 ), becoming less steep than the average late luminosity decline of normal SNII (� 1 mag (100d) −1 ). This dense ( u