The physical conditions of the interstellar medium (ISM) play a profound role in influencing star formation activity within galaxies. However, the exact mechanisms by which the physical properties of the ISM regulate star formation remain poorly understood. Therefore, it is crucial to study the different components of the ISM through observations of star-forming regions. The Orion Nebula, a well-known active star-forming region, hosts a variety of objects, including Young Stellar Objects (YSOs), massive star clusters, photodissociation regions (PDRs), and layered ionized gases. Its relative proximity (414 ± 7 pc) makes it an ideal target for detailed studies of the ISM in star-forming environments.
HII regions primarily emit radiation through thermal processes, though a few have been recently reported to exhibit nonthermal emissions. While recent studies have attempted to explain these nonthermal emissions, the observational results are still relatively new and not yet fully understood. Leveraging the enhanced capabilities of the upgraded Giant Metrewave Radio Telescope (uGMRT), we have conducted a detailed study of the ISM in the Orion region. In this talk, I will present findings from wide-band observations of the Orion Nebula at unique low-frequency bands using uGMRT. We have generated a reliable spectral index map from deep continuum images from band-3 (300–500 MHz) and band-4 (635–735 MHz) by analyzing uGMRT data. To validate our method, we tested it on simulated uGMRT data, confirming the robustness of our results.
Our observations indicate the presence of nonthermal emissions in certain parts of the region. I will also present multi-wavelength results that suggest these emissions could be attributed to cosmic rays powered by stellar winds from massive stars in the star clusters or turbulent jet activities associated with YSOs.