Related papers: A Statistical Inference Method for Interpreting th…
The forward fitting of solar flare observations with radiation-hydrodynamic simulations is a common technique for learning about energy deposition and atmospheric evolution during these explosive events. A frequent spectral line choice for…
We derive exact expressions for the degree of lineal polarization over a resolved or integrated stellar disc due to resonance scattering and the Hanle effect from a dipolar or quadrupolar distribution of magnetic fields. We apply the theory…
Coronal oscillations offer insight into energy transport and driving in the solar atmosphere. Knowing its polarisation state helps constrain a wave's displacement and velocity amplitude, improving estimates of wave energy flux and…
We completed observations with the Effelsberg 100-m radio telescope to measure the polarised emission from a complete sample of Compact Steep-Spectrum sources. We observed the sources at four different frequencies. We complemented these…
Theoretical investigations predicted that high spatio-temporal resolution observations in the Sr I 4607 A line must show a conspicuous scattering polarization pattern at the solar disk-center, which encodes information on the unresolved…
Solar flares involve impulsive energy release, which results in enhanced radiation over a broad spectral range and a wide range of heights. In particular, line emission from the chromosphere can provide critical diagnostics of plasma…
The spectral line polarization encodes a wealth of information about the thermal and magnetic properties of the solar atmosphere. Modeling the Stokes profiles of strong resonance lines is, however, a complex problem both from the…
The weak, turbulent magnetic fields that supposedly permeate most of the solar photosphere are difficult to observe, because the Zeeman effect is virtually blind to them. The Hanle effect, acting on the scattering polarization in suitable…
The physics of the Hanle effect is briefly reviewed, and its application as a diagnostic of hot star magnetic fields is described. Emphasis is given to the practicalities of using spectropolarimetry of resolved wind emission lines to infer…
The impact of the optical field polarization on the spectrum of magnetically-induced transitions, a class of transitions forbidden at zero magnetic field, is studied with a weak-probe sub-Doppler technique. The high spectral resolution of…
We present new measurements of the flux power-spectrum P(k) of the $z<0.5$ HI Lyman-$\alpha$ forest spanning scales k ~ 0.001-0.1 s/km. These results were derived from 65 far ultraviolet quasar spectra (resolution R~18000) observed with the…
We carry out a theoretical study of the polarization of the solar Mg II h-k doublet (including its extended wings) and the subordinate UV triplet around 280 nm. These lines are of great diagnostic interest, as they encode information on the…
Since the Lalpha rocket observations of (Gabriel, Solar Phys. 21, 392, 1971), it has been realized that the hydrogen (H) lines could be observed in the corona and offer an interesting diagnostic for the temperature, density, and radial…
Solar magnetic fields alter scattering polarization in spectral lines like Sr I at 4607 {\AA} via the Hanle effect, making it a potential diagnostic for small-scale mixed-polarity photospheric magnetic fields. Recently, observational…
The formation of shocks within the solar atmosphere remains one of the few observable signatures of energy dissipation arising from the plethora of magnetohydrodynamic waves generated close to the solar surface. Active region observations…
Aims. To investigate the magnetic field geometry and waves in the region near the Sun where the heliospheric current sheet is formed. Methods. One good example of apparent open and closed field lines was found and its fields and plasmas…
High sensitivity observations of Halpha polarization of 30 flares of different sizes and disk positions are reported. Both filter and spectrographic techniques have been used. The ZIMPOL system eliminates spurious polarizations due to…
Statistical properties of turbulent magnetic fields in radio-synchrotron sources should imprint on the statistics of polarimetric observables. In search of these imprints, we calculate correlation and cross-correlation functions from a set…
The Hanle effect has been proposed as a new diagnostic of circumstellar magnetic fields for early-type stars, for which it is sensitive to field strengths in the 1-300 G range. In this paper we compute the polarized P-Cygni line profiles…
The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at l~20 and bump at l~40. One explanation for this structure is the presence of features in the primordial curvature…