| Name: Yash Agrawal |
| Affiliation: Raman Research Institute |
| Conference ID: ASI2026_802 |
| Title: SARAS: Insights from RFI survey and Recent Deployments |
| Abstract Type: Poster |
| Abstract Category: Galaxies and Cosmology |
| Author(s) and Co-Author(s) with Affiliation: Yash Agrawal(Raman Research Institute), Saurabh Singh(Raman Research Institute), Girish B. S.(Raman Research Institute), Somashekar R.(Raman Research Institute), Srivani K. S.(Raman Research Institute), Raghunathan A.(Raman Research Institute), Vishakha S. Pandharpure(Raman Research Institute), Udaya Shankar N.(Raman Research Institute), Keerthipriya S.(Raman Research Institute), Mayuri Sathyanarayana Rao(Raman Research Institute) |
| Abstract: The Cosmic Dawn and Epoch of Reionization mark an important era in the Universe’s evolution. This is when the first stars and galaxies formed, followed by heating and reionization of the intergalactic medium. Today’s Universe is fully ionized, but the exact astrophysical parameters of this process remain poorly constrained. The redshifted 21-cm line from neutral hydrogen offers a unique window into this epoch, providing insights into the thermal and ionization history of the early Universe. Due to its coupling with the hydrogen spin temperature, standard cosmological models predict a weak, all-sky global signal originating from this era. The predicted sky-averaged global 21-cm signal component corresponding to 6 < z < 34 is redshifted to metre wavelengths and lies between 40 to 200 MHz. Detecting this signal, however, is extremely challenging as it is buried beneath foreground emissions that are about six orders of magnitude stronger. Extraction requires precise modeling and subtraction of foregrounds, along with careful treatment of instrumental systematics. The SARAS experiment seeks to detect this global 21-cm signal. However, several channels in this frequency band are occupied by various terrestrial and satellite-based transmitters, generating Radio Frequency Interference (RFI). This poses a challenge for scientific observations. The presence and extent of these transmissions vary by location. Understanding the RFI environment of potential deployment locations is crucial for selecting suitable deployment sites and ensuring data integrity. Therefore, choosing a location for conducting science observations must be preceded by a comprehensive RFI survey of candidate observation sites. We present insights from recent RFI surveys conducted to identify potential locations for SARAS observations. We describe the methodologies employed for RFI detection and characterization, summarize the RFI environments observed across different sites, and share findings from the latest SARAS deployments aimed at advancing global 21-cm cosmology. |
