Talks

The GMRT High Resolution Southern Sky (GHRSS) survey aims to uncover new pulsars and transients at low radio frequencies (Band 3 of GMRT at 400 MHz ) with high time (81.92 microsec) and frequency resolution. In this talk, I will present recent developments in the GHRSS data processing pipeline to improve the efficiency and depth of pulsar searches. Key upgrades include the implementation of an adaptive dispersion measure (DM) stepping strategy to optimize sensitivity across a wide DM range, and the integration of a machine learning-based candidate classification system to automate and refine candidate selection. Additionally, I will discuss the application of the Fast Folding Algorithm (FFA) to the GHRSS data, targeting the discovery of long-period pulsars often missed in conventional FFT-based searches. These advancements, along with new observational efforts, significantly strengthen the GHRSS survey’s capabilities in probing the pulsar population of the Southern sky.

We present results for searches for astrophysical neutrinos from pulsars, magnetars,  and FRBs. We show that the combined Super-Kamiokande and MACRO data show a  2.6 sigma spatial coincidence excess from PSR B1509-58 and then propose  additional tests to ascertain if this excess corresponds to an astrophysical signal . We then present results for searches for TeV energy neutrinos from pulsars,magnetars,  and FRBs using the publicly released  IceCube 10-year point source catalog.

Fast X-ray transients (FXTs) are singular, short bursts in soft X-rays (~0.3–10 keV) that last from minutes to hours. Their origin remains unclear, and they have been associated with various progenitor mechanisms, including long-duration gamma-ray burst association, the tidal disruption of a white dwarf by an intermediate-mass black hole, a magnetar formed as the aftermath of a binary neutron star merger whose spin-down powers the burst, and a core-collapse supernova shock breakout. The newly launched X-ray survey mission, Einstein Probe (EP), is revolutionising the field by enabling the discovery and prompt follow-up of FXTs, effectively doubling the number of known extragalactic events. In my talk, I will discuss our ongoing search for multiwavelength counterparts — particularly at optical and radio wavelengths — of FXTs discovered by EP, and their role in characterising the nature of these transients.

Now approaching completion, the TRAPUM (TRAnsients and PUlsars with MeerKAT) project has ushered in a new era of pulsar discovery. Over its 5 year campaign, TRAPUM has systematically targeted globular clusters, nearby galaxies and high-energy sources lacking known radio counterparts, yielding hundreds of new pulsars—including a remarkable population of fast-spinning millisecond pulsars (MSPs) as well as slow pulsars. Among these are numerous exotic binaries, such as black widow and redback systems, double neutron star systems as well as a surge of new pulsars in the Magellanic Clouds. A highlight is a candidate neutron star–black hole binary in NGC 1851, potentially probing the elusive LIGO “mass gap.”

These discoveries have been enabled by TRAPUM’s dedicated multibeam beamformer and GPU-based high-time-resolution processing system, technologies that have dramatically expanded MeerKAT’s capability for wide-field, sensitive pulsar searches. This infrastructure has also allowed quasi-real-time data analysis, demonstrating the survey’s potential as a technical and scientific pathfinder for the SKA.

As TRAPUM nears its conclusion, its instrumentation, methodologies, and scientific outcomes highlight the transformative power of interferometric pulsar surveys and provide crucial lessons for the next generation of large-scale radio time-domain projects.

We present a systematic investigation aimed at probing potential associations between historic local Universe core-collapse supernovae (CCSNe) and fast radio bursts (FRBs). Motivated by the growing evidence that young magnetars may power at least a subset of FRBs, we cross-match a sample of Type II and Ib/c CCSNe within 200\,Mpc, observable with the CHIME telescope, against the FRB events reported in CHIME/FRB Catalog-1. Our analysis employs rigorous selection criteria based on spatial coincidence, dispersion measure, and scattering constraints to identify candidate associations that could directly test the young magnetar progenitor model. Although our search yields a candidate match, the probability of a chance alignment remains high, precluding a definitive association at this stage. Nonetheless, the study demonstrates the viability of this cross-matching approach and underscores the need for dedicated follow-up observations of promising candidates to search for persistent or transient radio activity indicative of a young magnetar. This work lays the groundwork for future observational efforts aimed at elucidating the connection between the explosive endpoints of massive stars and the enigmatic FRB phenomenon.