We present a list of tailed radio galaxies using the Tata Institute of Fundamental Research (TIFR) Giant Metrewave Radio Telescope (GMRT) Sky Survey Alternative Data Release 1 (TGSS ADR1) at 150 MHz. We visually examined 5336 image fields and found 264 tailed radio galaxies. Tailed radio galaxies are classified as wide-angle tailed (WAT) galaxies or narrow-angle tailed (NAT) galaxies, based on the angle between the two jets of the galaxy. Our sample of tailed radio galaxies included 203 WAT- and 61 NAT-type sources. These newly identified tailed sources are significant additions to the list of known tailed radio galaxies. The source morphology and luminosity features of the various galaxies and their optical identifications are presented. Other radio properties and general features of the sources are also discussed.

We present new results of lower ionospheric disturbances due to the extremely severe cyclonic storm Fani over northeastern part of the Indian Ocean. Very low frequency radio signal received at Kolkata, India, and mesospheric temperature and ozone concentration data from the NASA's TIMED satellite are used for this purpose. Significant wave‐like oscillations and strong amplitude anomalies in daytime and nighttime VLF signal were observed when the cyclone center was within ∼700 km from the receiver. Both the mesospheric ozone concentration and temperature showed maximum anomalies beyond 3σ during the cyclone period. Maximum ozone anomaly and maximum VLF anomaly occurred on the same day when cyclone intensity was maximum, while the maximum temperature anomaly occurred on the next day during landfall. Mesospheric temperature enhancement around VLF reflection heights indicates changes in the chemical composition and electron‐neutral balance in the D region ionosphere. Simulation of VLF signal showed that the D region reflection height decreased by 7.9 km and the D region electron density increased by ∼20 times compared to precyclone midnight values at the maximum perturbed area along the propagation path. Wavelet analysis confirmed significant enhancement of atmospheric gravity waves spectrum with periods 10 min to 2 hr around landfall. Further, a strong anticorrelation between total wavelet power in the wave band of periods 10–30 min and cyclone pressure suggests a possibility of monitoring cyclone intensity from mesospheric gravity waves using VLF radio measurements.

This study investigates the impact on the Earth’s ionosphere of a severe geomagnetic storm (Dst $\sim -212$ nT) that began on 23 April 2023 at around 17:37 UT according to very low-frequency (VLF, 3–30 kHz) or low-frequency (LF, 30–300 kHz) radio signals and ionosonde data. We analyze VLF/LF signals received by SuperSID monitors located in mid-latitude (Europe) and low-latitude (South America, Colombia) areas across nine different propagation paths in the Northern Hemisphere. Mid-latitude regions exhibited a daytime amplitude perturbation, mostly an increase, by ∼3–5 dB during the storm period, with a subsequent recovery after 7–8 days post April 23. In contrast, signals received in low-latitude regions (UTP, Colombia) did not show significant variation during the storm-disturbed days. We also observe that the 3-hour average of foF2 data declined by up to 3 MHz on April 23 and April 24 at the European Digisonde stations. However, no significant variation in foF2 was observed at the low-latitude Digisonde stations in Brazil. Both the VLF and ionosonde data exhibited anomalies during the storm period in the European regions, confirming that both D- and F-region ionospheric perturbation was caused by the severe geomagnetic storm.

Phase stability at low radio frequencies is severely impacted by ionospheric propagation delays. Radio interferometers such as the giant metrewave radio telescope (GMRT) are capable of detecting changes in the ionosphere’s total electron content (TEC) over larger spatial scales and with greater sensitivity compared to conventional tools like the global navigation satellite system (GNSS). Thanks to its unique design, featuring both a dense central array and long outer arms, and its strategic location, the GMRT is particularly well-suited for studying the sensitive ionospheric region located between the northern peak of the equatorial ionization anomaly (EIA) and the magnetic equator. In this study, we observe the bright flux calibrator 3C48 for ten hours to characterize and study the low-latitude ionosphere with the upgraded GMRT (uGMRT). We outline the methods used for wideband data reduction and processing to accurately measure differential TEC ($\delta \mathrm{TEC}$) between antenna pairs, achieving a precision of< mTECU (1 mTECU = ${10}^{-3}$ TECU) for central square antennas and approximately mTECU for arm antennas. The measured $\delta \mathrm{TEC}$ values are used to estimate the TEC gradient across GMRT arm antennas. We measure the ionospheric phase structure function and find a power-law slope of $\beta =1.72\pm 0.07$, indicating deviations from pure Kolmogorov turbulence. The inferred diffractive scale, the spatial separation over which the phase variance reaches $1{\mathrm{rad}}^2$, is ∼6.66 km. The small diffractive scale implies high phase variability across the field of view and reduced temporal coherence, which poses challenges for calibration and imaging.