Related papers: Self-absorption in the solar transition region
The Interface Region Imaging Spectrograph (IRIS) of the NASA small explorer mission provides significantly more complete and higher resolution spectral coverage of the dynamical conditions inside the chromosphere and transition region (TR)…
Lyman alpha absorber correlations contain information about the underlying density distribution associated with a particular class of absorbers. As such, they provide an opportunity to independently measure the "bias" of the Lyman alpha…
Ellerman bombs (EBs) seem to be a part of a whole spectrum of phenomena that might have the same underlying physical mechanism, but with observed characteristics which pose a considerable challenge to models. The aim of this study is to…
Photoabsorption of atomic oxygen in the energy region below the $\rm 1s^{-1}$ threshold in x-ray spectroscopy from {\it Chandra} and {\it XMM-Newton} is observed in a variety of x-ray binary spectra. Photoabsorption cross sections…
This study investigated spectral changes in the absorption cross-sections of single strong coupling systems composed of single silver nanoparticle dimers and a few dye molecules during the quenching of surface-enhanced resonant Raman…
Ellerman bombs (EBs) are observable signatures of photospheric small-scale magnetic reconnection events. The reliable automatic detection of EBs would enable the study of the impact of magnetic reconnection on the Sun's dynamics. We aim to…
The Interface Region Imaging Spectrograph (IRIS) reveals small-scale rapid brightenings in the form of bright grains all over coronal holes and the quiet sun. These bright grains are seen with the IRIS 1330 \AA, 1400 \AA\ and 2796 \AA\…
Interchange reconnection is thought to play an important role in determining the dynamics and material composition of the slow solar wind that originates from near coronal hole boundaries. To explore the implications of this process we…
Some hot DA stars exhibit circumstellar absorption in the metal resonance lines in their spectra. In many cases, these circumstellar features are unresolved from those originating in the photosphere. To better understand the effect this…
We use Interface Region Imaging Spectrograph (IRIS) spacecraft data to study a group of Chromospheric ultraviolet bursts (UVBs) associated with an active region. We classify the UVBs into two types: smaller ones that can only be measured…
Details of a theory of self-broadening of hydrogen lines are presented. The main features of the new theory are that the dispersive-inductive components of the interaction (van der Waals forces) have been included, and the resonance…
Accurate atomic transition data are important in many astronomical research areas especially in line spectroscopy study. Whereas transition data of He-like and H-like ions (i.e., ions at high-charge states) are accurately calculated, that…
Magnetic reconnection plays an integral part in nearly all models of solar flares and coronal mass ejections (CMEs). The reconnection heats and accelerates the plasma, produces energetic electrons and ions, and changes the magnetic topology…
We aim at investigating the formation of jet-like features in the lower solar atmosphere, e.g. chromosphere and transition region, as a result of magnetic reconnection. Magnetic reconnection as occurring at chromospheric and transition…
We present the results of a search for metal absorption lines in the spectra of background QSOs whose sightlines pass close to foreground QSOs. We detect MgII(2796,2803) absorption in Sloan Digital Sky Survey (SDSS) spectra of four z>1.5…
The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyman-{\alpha} during a suborbital rocket flight on September 3, 2015. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations…
In rare-earth ion-doped crystals, inhomogeneous absorption profiles reflect the distribution of local environments experienced by individual ions. While each optical transition probes this distribution differently, their fine spectral…
Gamma-rays and neutrons are the only sources of information on energetic ions present during solar flares and on properties of these ions when they interact in the solar atmosphere. The production of {\gamma}-rays and neutrons results from…
We present details regarding the construction of a composite spectrum of quasar (QSO) absorption line systems. In this composite spectrum we identify more than 70 absorption lines, and observe oxygen and hydrogen emission features at a…
We re-examine scattering of photons near the Lyman-alpha resonance in the intergalactic medium (IGM). We first derive a general integral solution for the radiation field around resonance when spin diffusivity is ignored. Our solution shows…