Study of Maser and Thermal Molecular Emission in the Vicinity of Selected Protostellar Objects With the Rt-22 Radio Telescope at Prao

At the early stage of the protostar existence, gas is mostly in molecular form, and the process of protostars development causes a variety of surrounding matter emission in molecular lines at many frequencies in any diapason. The goal of this work is to measure molecular radio lines parameters in the vicinity of some young protostar objects to improve the understanding of their evolutionary trends. Observations were carried out with the RT-22 radio telescope of the Pushchino Radio Astronomical Observatory of the Lebedev Physical Institute from July 2022 until May 2023. Two standard transistor receivers were used, which operated at frequencies of 20–24 GHz (range 13.5 mm) and 36.2–37.7 GHz (range 8 mm). We studied emission in the lines of four molecules, each one being a “tracer” of the environmental physical state: water (H2O), methanol (CH3OH), ammonia (NH3) and cyanoacetylene (HC3N). Observational results were obtained for three IRDC objects, for two CORE-type objects and for the star forming region Onsala-1. Radio emission in the water vapor line was detected in all studied objects, except for IRDC G027.94–00.47. For three objects: IRDC G028.37+0.07b, IRDC G024.33+0011 and Onsala-1, the rotational and kinetic temperatures in the radiation region were determined from the emission spectra of the ammonia molecule, and estimates of the concentration of ammonia and the density of molecular hydrogen were obtained. Emission in lines of cyanoacetylene was detected in the direction of to sources IRDC G028.37+0.07b and Onsala-1, and the column density of this molecule was determined.