| Name: | Ajay Kumar |
| Affiliation: | National centre for radio astrophysics |
| Conference ID : | ASI2024_992 |
| Title : | GMRT Regular Observations Of fast Transients (GROOT) - FRB20220912A: Burst Activity Rate, Energetics and Population properties |
| Authors : | Ajay Kumar, Yash Bhusare, Arpan Pal, Banshi Lal, Puja Majee, Vishweshwar Ram Marthi, Shriharsh Tendulkar, Yogesh Maan |
| Authors Affiliation: | National centre for Radio Astrophysics |
| Mode of Presentation: | Poster |
| Abstract Category : | Galaxies and Cosmology |
| Abstract : | Observations of repeating fast radio bursts (FRBs) allow us to probe the nature of the emission mechanisms and the changes in their local environments in detail. They have shown variable activity levels over time. The nature of repetition can be sporadic, periodic (e.g. FRB 20180916B, FRB20121102A) or long periods of quiescence interrupted by a period of hyperactivity (e.g. FRB 20201124A). Studying variations over longer timescales provide clues to the possible progenitors.
In this study, we focus on FRB 20220912A, which was initially discovered by CHIME/FRB on September 12, 2022 and has displayed exceptionally high activity levels reminiscent of only a few other repeating FRBs, such as FRB 20201124A.
Due to its precise localization, we could leverage dual-band observations (band 3 and band 4) with uGMRT in phased array mode spanning the frequency range from 300 MHz to 750 MHz, which closely aligns with the CHIME telescope's range (400-800 MHz) but has at least 5 times the sensitivity. We study the lower end of the energy distribution compared to CHIME. To ensure the robustness of our results, we conducted a completeness analysis by injecting simulated bursts and estimating the detection efficiency as a function of fluence.
Over the course of our regular observations, from November 2022 to July 2023, we detected a total of 491 bursts. Our analysis shows at least a factor of two variations in the burst rate between observations separated by a few weeks. Additionally, the burst rate behaviour is also observed to be frequency dependent.
Our study unveils several intriguing properties of the burst populations within FRB 20220912A, including the temporal and frequency-dependent variation in burst rates, as well as the energetics of these bursts. We will discuss these properties as well as the results from periodicity searches in burst repetition. |
