PHYSICAL-PROPERTIES OF THE IONIZED-GAS AND BRIGHTNESS DISTRIBUTION INNGC-4736

In this work we study the galaxy NGC 4736, using narrow band interfere nce filters imaging centered at the emission lines [OII](lambda lambda 3727+3729), H beta, [OIII](lambda 5007), H alpha, [SII](lambda 6716+6 730) and [SIII](lambda 9070) and nearby continua. We have obtained siz es, positions, emission line absolute fluxes, and continua intensities for 90 HII regions, mainly distributed in a ring-like structure of 3. 2 kpc in diameter. The H alpha luminosities are in the range 37.3 less than or equal to log L-H alpha less than or equal to 39.4 erg s(-1). The HII regions size distribution presents a characteristic diameter D -0 = 115 pc and verifies the relation log(L-H alpha) proportional to D -3. The temperature of the ionizing sources and the metallicity of the HII regions are respectively in the ranges 3.410(4) less than or simi lar to T-star less than or similar to 4.010(4) K and 8.5 less than or similar to 12 + log (O/H) less than or similar to 9.3. The masses of t he ionizing clusters are in the range 5 10(3) less than or similar to M-T/M. less than or similar to 2 10(5). The continua radial surface br ightness distribution is better fitted by the superposition of a de Va ucouleurs', a thin and a thick exponential disk laws. The monochromati c colors show that outside the star forming ring the disk presents a y ounger stellar population than inside it.