In the frame of the project for complex study of blue compact galaxies (BCGs) their photometric study is conducted. The basic purpose of this work is comparison of morphology of stellar and gas components in these galaxies, estimation of the current star formation rate and the total number of young ionizing O stars.

CCD photometric observations (in H-alpha filter and in the R-filter) of 6 BCGs were carried out at the prime focus of the 6 m telescope. The magnitudes in R-band and H-alpha fluxes were calculated. On the basis of these data radial profiles were determined. A comparison of morphology of stellar component and hot gas was performed. In the complex analysis of the obtained data there were also used for these BCGs the results of HI observations in the 21 cm line at the 300 m Nancay radio telescope and the 6 m telescope spectroscopy.

It is shown that the current star formation rate (SFR) for these galaxies is high and typical of BCGs (0.07-7.3 Msun/yr). The stores of neutral gas would be run out of these BCGs only in (4-17)*10^8 years. The estimate of the number of young O7 stars in giant HII regions of the studied BCGs ranges from 500 to 50000. This is also evidence for the high current star formation rate. The morphology of half of the galaxies studied in H-alpha emission (hot ionized gas) shows a great difference from that of the stellar component.

Images of two galaxies observed with the 6 m telescope are shown in Figure The morphology of stars and hot gas (H-alpha-image) in the star-forming region of Mkn~996 is the same. But for the case of Mkn~487 morphologies of stars and hot gas differ appreciably.

Copy of this figures in PostScript file (96Kb)

1. Kniazev A.Yu.
2. Pustilnik S.A.
3. Ugryumov A.V.
4. Lipovetsky V.A.

• Korablina N.B. - SAI (Moscow)
• Artamonov B.P. - SAI (Moscow)

14 January 1999