| Name: | Md Rashid |
| Affiliation: | Indian Institute of Science (IISc), Balgalore |
| Conference ID : | ASI2024_510 |
| Title : | A low radio frequency study of Orion: Indications of nonthermal emission |
| Authors : | Md Rashid1, Nirupam Roy1, Samir Choudhuri2 |
| Authors Affiliation: | 1 Dept. of Physics, Indian Institute of Science (IISc), Bengaluru - 560012, India.
2 Dept. of Physics, Indian Institute of Technology Madras (IITM), Chennai - 600036, India. |
| Mode of Presentation: | Poster |
| Abstract Category : | Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Abstract : | The physical conditions of the interstellar medium (ISM) profoundly influence the star formation activity of galaxies. However, the exact role of the physical properties of ISM in regulating star formation is yet to be understood. Hence, it is crucial to constrain these properties
through observations in the star-forming regions. The famous Orion H II region is one such region
hosting a variety of objects, e.g., young star clusters, predominantly atomic photodissociation
region (PDR), and layered ionized gases. Moreover, its proximity (414 ± 7 pc) makes it an ideal
target for studying vital properties of the ISM in the star-forming region and physical processes
happening in them. H II regions dominantly emit through thermal radiation mechanisms. However, a handful of H II regions are reported to emit nonthermal emissions. Recent studies have made efforts to explain such atypical nonthermal emissions through physical models. However,
such observational results are relatively new and yet to be understood clearly. Using the enhanced
capabilities of the upgraded Giant Metrewave Radio Telescope (uGMRT), we have studied the
ISM in the Orion region. In this talk, I will present the results of the wide-band observations
of the Orion nebula at unique low-frequency bands of uGMRT. From deep continuum images of
band-3 (300 MHz – 500 MHz) and band-4 (635 MHz – 735MHz) of uGMRT, we have produced
a reliable spectral index map. We are reporting indications of nonthermal emission from some
parts of the Orion region. To establish the reliability of the spectral index map, we are also validating the reliability of the spectral map produced through simulated data of extended emission
for uGMRT. I will also discuss possible physical scenarios and mechanisms that may explain this new
finding. |
