Related papers: On the correlation between Ca and Halpha solar emi…
Sun-as-a-star analyses serve as a bridge for comparative studies on solar and stellar activities. To investigate the typical Sun-as-a-star Ha temporal spectral characteristics in solar eruption source regions, we analyzed five different…
We analyze 15 years of Fermi-LAT data and produce a detailed model of the Sun's inverse-Compton scattering emission (solar halo), which is powered by interactions between ambient cosmic-ray electrons and positrons with sunlight. By…
Quasi-biennial oscillation (QBO) of solar magnetic activities is intrinsic to dynamo mechanism, but still far from fully understood. In this work, the phase and amplitude asymmetry of solar QBO of Halpha flare activity in the northern and…
Polarisation measurements of solar flares at millimetre-waves were used to investigate the magnetic field configuration of the emitting sources. We analyse two solar flares (SOL2013-02-17 and SOL2013-11-05) observed by the POlarisation…
We combine the latest spectrally stacked data of 21-cm emission from the ALFALFA survey with an updated version of the Dark Sage semi-analytic model to investigate the relative contributions of secular and environmental astrophysical…
Observations of flare emissions in the optical continuum are very rare. Therefore, the analysis of such observations is useful and may contribute to our understanding of the flaring chromosphere and photosphere. We study the white light…
The steady-state gamma-ray emission from the Sun is thought to consist of two emission components due to interactions with Galactic cosmic rays: (1) a hadronic disk component, and (2) a leptonic extended component peaking at the solar edge…
The Fourier analysis of the CME occurrence data observed by the SOHO satellite shows significant power around 1.9 yr., 1.2 yr., 265 day, 39 day and 26 day periodicities which are almost similar to the periodicities detected in the Fourier…
Solar flares are 3D phenomenon but modelling a flare in 3D, including many of the important processes in the chromosphere, is a computational challenge. Accurately modelling the chromosphere is important, even if the transition region and…
Blazars show optical and $\gamma$-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data at optical,…
The correlation scale and the Taylor scale are evaluated for interplanetary magnetic field fluctuations from two-point, single time correlation function using the Advanced Composition Explorer (ACE), Wind, and Cluster spacecraft data during…
Aiming at the detection of cosmological gas being accreted onto galaxies of the local Universe, we examined the Halpha emission in the halo of 164 galaxies in the field of view of the Multi-Unit Spectroscopic Explorer Wide survey (\musew )…
A deep objective-prism survey for H-alpha emission stars towards the Canis Major star-forming clouds was performed. A total of 398 Halpha emitters were detected, 353 of which are new detections. There is a strong concentration of these…
We study the relationship between full-disk solar radiative flux at different wavelengths and average solar photospheric magnetic-flux density, using daily measurements from the Kitt Peak magnetograph and other instruments extending over…
A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and…
Stellar activity can be observed at different wavelengths in a variety of different activity indicators. We investigated the correlation between coronal and chromospheric emissions by combining X-ray data from stars detected in the eROSITA…
Recently, many superflares on solar-type stars were discovered as white-light flares (WLFs). A correlation between the energies (E) and durations (t) of superflares is derived as $t\propto E^{0.39}$, and this can be theoretically explained…
Lyman-$\alpha$ nebulae are usually found in massive environments at high redshift ($z > 2$). The origin of their Lyman-$\alpha$ (Lya) emission remains debated. Recent polarimetric observations showed that at least some Lya sources are…
We investigated the radiative emission of different types of solar features in the spectral range of the Ca II K line. We analyzed full-disk 2k x 2k observations from the PSPT Precision Solar Photometric Telescope. The data were obtained by…
In an attempt to constrain and understand the emission mechanism of gamma rays, we perform a cross-correlation analysis of 15 blazars using light curves in millimetre, optical and gamma rays. We use discrete correlation function and…