Multi-frequency study of large size radio galaxies 3C 35 and 3C 284

We report multi-frequency observations of large radio galaxies 3C 35 and 3C 284. The low-frequency observations were done with Giant Metrewave Radio Telescope starting from $\sim$150 MHz, and the high-frequency observations were done with the Very Large Array. We have studied the radio morphology of these two sources at different frequencies. We present the spectral ageing map using two of the most widely used models, the Kardashev-Pacholczyk and Jaffe-Perola models. Another more realistic and complex Tribble model is also used. We also calculate the jet-power and the speed of the radio lobes of these galaxies. We check for whether any episodic jet activity is present or not in these galaxies and found no sign of such kind of activity.Comment: 18 pages, comments are welcom

Spectral index variation across X-shaped radio galaxies

The formation mechanism of the enigmatic subclass of radio galaxies, called 'X-shaped radio galaxies' (XRGs), or 'winged' radio galaxies, which account for $\sim 10\%$ of the radio galaxy population, can be effectively constrained using the radio spectral-index distribution across their twin pairs of radio lobes. If indeed, the existing claims of no systematic spectral index difference between the wing and the associated primary lobe are valid in general, this would provide impetus to the XRG model attributing their origin to an unresolved binary of active supermassive black holes within the nucleus of the host galaxy. To investigate this interesting possibility, we have mapped spatial variation of spectral index for a well-defined sample of 25 XRGs, by combining their 1.4 GHz VLA (FIRST survey)/uGMRT maps with their 144 MHz maps (LoTSS-DR2). This has yielded the best available combination of sensitivity, angular resolution, frequency range and sample size, for spectral mapping of an XRG sample. A rich diversity of spectral index patterns is thus revealed in our XRG sample, but we find at most one case where a secondary lobe (wing) exhibits a flatter spectrum compared to its associated primary lobe. We conclude that such a spectral pattern is exceedingly rare and by no means a common trait of XRGs.Comment: 20 pages, 2 figures, 2 tables, accepted for publication in MNRA

Discovery of Jet-Induced Soft Lags of XTE J1550-564 during Its 1998 Outburst

X-ray time lags are complicated in nature. The exact reasons for complex lag spectra are yet to be known. However, the hard lags, in general, are believed to be originated due to the inverse Comptonization process. But, the origin of soft lags remained mischievous. Recent studies on "Disk-Jet Connections" revealed that the jets are also contributing to the X-ray spectral and timing properties in a magnitude which was more than what was predicted earlier. In this article, we first show an exact anti-correlation between X-ray time lag and radio flux for XTE J1550-546 during its 1998 outburst. We propose that the soft lags might be generated due to the change in the accretion disk structure along the line of sight during higher jet activity.Comment: The article contains six pages and two figures. Open access publisher link https://www.mdpi.com/2504-3900/17/1/