Aims. We aim to investigate the extreme variability properties of the TeV blazar S4 0954+65 using optical photometric and polarisation observations carried out between 2017 and 2023 using three ground-based telescopes. Methods. ...

1ES1927+654 is a nearby active galactic nucleus (AGN) that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability patterns at timescales of months to years. Here we report ...

An integrated campaign “Suryagrahan-2019” with multi-institutional support was conducted by launching a series of radiosondes/ozonesondes over 6-different locations in India along with the operation of ST/MST radars and ...

We use the largest catalog of open clusters in the post-Gaia era to provide an observational view of the Galactic disk. By compiling physical parameters such as age, distance, and kinematic information, we investigate the ...

The highly variable blazar OJ 287 is commonly discussed as an example of a binary black hole system. The 130 yr long optical light curve is well explained by a model where the central body is a massive black hole of 18.35 ...

This paper deals with the design and fabrication of edge-coupled band pass filter (BPF) circuit (fifth order) on microwave laminate for 4.5 GHz ± 0.5 GHz application. The design of filter is realized on a high quality ...

We detected a possible quasi-periodic oscillation (QPO) of ∼71 d in the 0.1–300 GeV γ-ray Fermi-Large Area Telescope light curve of the high-redshift flat spectrum radio quasar B2 1520+31. We identify and confirm that ...

We examined long-term aerosol optical depth (AOD) trends over 53 sites across the globe which comprise 49 sites from the Aerosol Robotic Network (AERONET) and 4 sites from the Sky radiometer Network (SKYNET) during 1995–2018. ...

Urban areas in developing countries are major sources of carbonaceous aerosols and air pollutants, pointing out the need for a detailed assessment of their levels and origin close to the source. A multi-instrument research ...

Matter falling onto black holes is hot, fully ionized and has to be necessarily transonic. Since the electrons are responsible for radiative cooling via processes like synchrotron, bremsstrahlung and inverse-Compton, the ...