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Development and qualification of the Feed-Select Mechanism for the Polarimetric and Helioseismic Imager on-board Solar Orbiter
Hirzberger, Johann; Woch, Joachim; Staub, Jan +5 more
The Solar Orbiter Polarimetric and Helioseismic Imager (SO/PHI) will provide maps of the magnetic vector and of the line-of-sight velocities in the solar photosphere. For reaching its science goals, SO/PHI is equipped with two telescopes: the high resolution channel (HRT) and the full disk channel (FDT). Since both optical channels are fed into a …
η Carinae: Particle acceleration and multimessenger aspects
Walter, R.; Balbo, M.
η Carinae is composed of two very massive stars orbiting each other in 5.5 years. The primary star features the densest known stellar wind, colliding with that expelled by its companion. The wind collision region dissipates energy and accelerates particles up to relativistic energies, producing nonthermal X‑ray and γ‑ray emission detected by Beppo…
Signatures of red-shifted foot points in the quiescent coronal loop system
Rao, Yamini K.; Srivastava, Abhishek K.; Kayshap, Pradeep +1 more
We observed quiescent coronal loops using multi-wavelength observations from the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO) on 13 April 2016. The flows at the foot points of such loop systems are studied using spectral data from the Interface Region Imaging Spectrograph (IRIS). The Doppler velocity distributions…
Image Estimation in the Presence of Irregular Sampling, Noise, and Pointing Jitter
Piazzo, Lorenzo
Subpixel real-time jitter detection algorithm and implementation for polarimetric and helioseismic imager
Volkmer, Reiner; Roma, David; Carmona, Manuel +12 more
The polarimetric and helioseismic imager instrument for the Solar Orbiter mission from the European Space Agency requires a high stability while capturing images, specially for the polarimetric ones. For this reason, an image stabilization system has been included in the instrument. It uses global motion estimation techniques to estimate the jitte…
Distance, Luminosity and evolutionary status of epsilon Aurigae (F0Iaep) from Gaia DR2 parallax
Muneer, S.; Parthasarathy, M.
From Gaia DR2 parallax of epsilon Aurigae the distance, Mv, Mbol, and log(L*/LMsun) are found to be 445 parsecs, -6.5 mag, -6.5 mag, and 4.5 respectively. These results clearly indicate that epsilon Aurigae (F0Iae) is post-AGB star. The progenitor of epsilon Aurigae is most likely an intermediate mass star of 4 to 5 solar masses or the progenitor …
Cassini CIRS and ISS opposition effects of Saturn's rings - I. C ring narrow or broad surge?
Déau, E.; Colwell, J. E.; El Moutamid, M. +6 more
We focus on the thermal and optical opposition effects of Saturn's C ring seen by Cassini CIRS (Composite InfraRed Spectrometer) at 15.7 {µ}m and ISS (Imaging Science Subsystem) at 0.6 {µ}m. The opposition surge is a brightness peak observed at low phase angle (α → 0°). Saturn rings' opposition surge was recently observed in reflected …
Investigation of the Outburst Activity of the Black Hole Candidate GRS 1739-278
Lutovinov, A. A.; Mereminskiy, I. A.; Filippova, E. V. +2 more
We have performed a joint spectral and timing analysis of the outburst of GRS 1739-278 in 2014 based on Swift and INTEGRAL data. We show that during this outburst the system exhibited both intermediate states: hard and soft. Peaks of quasi-periodic oscillations (QPOs) in the frequency range 0.1-5 Hz classified as type-C QPOs have been detected fro…
Opposite Polarity Magnetic Fields and Convective Downflows in a Simulated Sunspot Penumbra
Rempel, Matthias; Bharti, Lokesh
Recent numerical simulations and observations of sunspots show a significant amount of opposite polarity magnetic fields within the sunspot penumbra. Most of the opposite polarity fields are associated with convective downflows. We present an analysis of 3D MHD simulations through forward modeling of synthetic Stokes profiles of the Fe I 6301.5 Å …
AU Pegasi revisited: period evolution and orbital elements of a peculiar Type II Cepheid
Szabados, László; Csörnyei, Géza
New analysis on the period changes of Type II Cepheid AU Peg is presented. The available recent photometric measurements were collected and analysed with various methods. The period has been found to be constant for certain time intervals, although increasing in overall, in contrast with the previous expectations, which suggested the period change…