Observations of the type IIn supernova 1999EL in the near infrared

Abstract We present the preliminary results of near-infrared photometric observations of the type IIn SN1999EL covering the period between 5 to 80 days after discovery. These infrared data represeat the second time that such extensive time and wavelength coverage has been achieved for a type IIn SN event. We estimate the absolute magnitudes of the SN at the moment of brightness maximum in J, H and K bands. If the luminosity of the SN event in the K band is powered mostly by the deposition of redioactive decay energy, the mass of radioactive 56Ni is estimated as 0.2M[odot]. The effect of blueing of the J, H, K light curves is discovered and explained by the interaction of the explosion shock and UV/optical flash with pre-existing dust in the circumstellar medium of the progenitor.