A SPECTROPHOTOMETRIC STUDY OF THE SEYFERT-1 GALAXY NGC-4253

CCD spectroscopic observations from [Ne V] lambda 3425 Angstrom to [S III] lambda 9532 Angstrom of the nucleus and circumnuclear region of t he Seyfert 1 NGC 4253 are presented. The nucleus shows circumnuclear e mission which is elongated 1.5 kpc to the north-east; the spectrum of this extranuclear emission is well fitted by H II region models with e ffective temperatures of 50 000 K. The kinematics of the high-excitati on gas is perturbed with respect to the low-ionization gas, showing ra dial motions compatible with an outflow wind. The nucleus is a strong Fe II emitter, and its spectrum shows high-excitation lines, such as [ Fe VII] lambda 6086 Angstrom and [Fe X] lambda 6374 Angstrom, which ar e produced by photoionization in the coronal-line region, Lines produc ed in high-density and low-ionization conditions, such as O I lambda 8 446 Angstrom and Mg II lambda 9220 Angstrom, are also detected; we sho w that these lines are produced by fluorescence with Ly beta. The near infrared Ca II triplet, detected in emission and in absorption, and t he Fe II emission are discussed in terms of the starburst model develo ped by Terlevich and collaborators.