| Name: Sridhar Gajendran |
| Affiliation: National Centre for Radio Astrophysics |
| Conference ID: ASI2026_441 |
| Title: Probing Long-Period Transients with GMRT Archival Data: Updates from LIGHT |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Sridhar Gajendran(National Centre for Radio Astrophysics, Pune - 411007, India), Jayanta Roy(National Centre for Radio Astrophysics, Pune - 411007, India), Chahat Dudeja(National Centre for Radio Astrophysics, Pune - 411007, India), Kshitij Bane(National Centre for Radio Astrophysics, Pune - 411007, India), Abhinav Narayan(Indian Institute of Technology Indore, Indore - 453552, India), Narendranath Patra(Indian Institute of Technology Indore, Indore - 453552, India) |
| Abstract: Long Period Transients (LPTs), one of the most rapidly emerging phenomena in the field of radio transients, are minute to hour timescale periodic events covering a broad energy range, bridging coherent and incoherent regimes. LPTs have the potential to graze the boundary between coherent and incoherent emitters, challenging the understanding of coherent versus incoherent radio emissions . Fewer than a dozen LPTs have been discovered so far, all found within the Galactic plane, and their emission mechanism remains poorly understood. These sources lie beyond the so-called “death valley” in the spin period and period derivative (P–Ṗ) diagram, where normal radio pulsar emission is expected to cease. Interestingly, some LPTs showed optical or X-ray counterparts, suggesting a wide range of possible origins. Proposed models include highly magnetized white dwarfs, binary systems, and ultra-long period magnetars. One remarkable LPT has been active since 1988 but was missed by traditional periodicity search methods. It also shows a possible connection with Fast Radio Bursts (FRBs). Such discoveries highlight the need for systematic studies using both archival and new observations. To explore this population, we have started the LIGHT (Long-period transIents in GMRT arcHival daTa) project using several years of archival uGMRT imaging data. We developed a GPU-accelerated fast imaging pipeline called GARUDA that searches for transients in image cubes and performs a time-domain periodicity search to detect ultra-slow, isolated, repeating bursts. The pipeline has been validated by recovering two known LPTs, J0901-4046 and GPM J1839–10, from archival GMRT data. With the GMRT’s unprecedented sensitivity and our new processing capabilities, we aim to probe previously unexplored regions of the transient parameter space. I will present recent progress from the LIGHT project, highlighting new candidate detections spanning both plausible astrophysical events and signals attributable to satellites. |
