STAR FORMATION AROUND INFRARED BUBBLE N24

Abstract

This work is devoted to the observation and analysis of the radiation of molecular
ammonia NH3 (1,1) and NH3 (2,2) in a large N24 infrared bubble. The results of the study make it
possible to determine the physical properties of the interstellar medium in the bubble and to
evaluate characteristics of the star formation process in the region.
The observational data were obtained in March 2018 at a 26-meter radio telescope at the
Xinjiang Astronomical Observatory at a frequency of 23 GHz. Data processing was carried out by
using CLASS program from the standard GILDAS spectrum package. The range of integrated
velocity was 60-70 km/h.
As a result of calculations, the distribution of matter in the region is shown. A map of
integrated intensity, which is an indicator localizing the region of star formation was constructed. 23
prestellar cores were found in the observed volume in the expanding N24 bubble. Based on the
correlation in the transferred masses of ammonia, constant rate of star formation in this region was
found. Also, temperature and density of different areas in the bubble are significantly different. In
consequence, high concentration of ammonia NH3 (1,1) and NH3 (2,2) takes place only inside the
cores. Thus, we concluded that observed cores at early stage of star formation.