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Related papers: Linear Polarization Features in the Quiet-Sun Phot…

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We present here the first systematic search of short timescale $\gamma$-ray flares from 29 high Galactic latitude BL Lac objects over 14 years of Fermi Large Area Telescope data. Using a combined Bayesian Blocks and HOP algorithm, we…

High Energy Astrophysical Phenomena · Physics 2024-05-14 Jinjie Yu , Nan Ding , Junhui Fan , Yunyong Tang , Jin Cao

The bulk of the quiet solar photosphere is thought to be significantly magnetized, due to the ubiquitous presence of a tangled magnetic field at subresolution scales with an average strength <B> ~ 100 G. This conclusion was reached through…

Solar and Stellar Astrophysics · Physics 2015-05-27 Nataliya Shchukina , Javier Trujillo Bueno

The CLASP2 (Chromospheric LAyer SpectroPolarimeter 2) sounding rocket mission was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of the Mg II h & k spectral region around 2800 Angstroms along a 200 arcsecond slit at…

The observed magnetic field on the solar surface is characterized by a very complex spatial and temporal behaviour. Although feature-tracking algorithms have allowed us to deepen our understanding of this behaviour, subjectivity plays an…

Solar and Stellar Astrophysics · Physics 2016-07-04 A. Y. Gorobets , J. M. Borrero , S. Berdyugina

We present the detection and characterization of fluctuations in linearly polarized emission from the atmosphere above the South Pole. These measurements make use of data from the SPT-3G receiver on the South Pole Telescope in three…

Full Stokes filter-polarimeters are key instruments for investigating the rapid evolution of magnetic structures on the solar surface. To this end, the image quality is routinely improved using a-posteriori image reconstruction methods. We…

Solar and Stellar Astrophysics · Physics 2015-06-03 A. Asensio Ramos , M. J. Martinez Gonzalez , E. Khomenko , V. Martinez Pillet

The behavior of the observed polarization amplitudes with spatial resolution is a strong constraint on the nature and organization of solar magnetic fields below the resolution limit. We study the polarization of the very quiet Sun at…

Solar and Stellar Astrophysics · Physics 2015-05-18 M. J. Martinez Gonzalez , R. Manso Sainz , A. Asensio Ramos , A. Lopez Ariste

Based on ray tracing in a smooth ionosphere described by the IRI-2016 model we have infered the seasonal-diurnal dynamics of radio noise observed by four mid-latitude HF radars. In the calculations, noise is assumed to propagate from the…

Space Physics · Physics 2022-10-05 O. I. Berngardt , J. -P. St. Maurice , J. M. Ruohoniemi , A. Marchaudon

The analysis of near infrared spectropolarimetric data at the internetwork at different regions on the solar surface could offer constraints to reject current modeling of these quiet areas. We present spectro-polarimetric observations of…

We analyze the spectral asymmetry of Stokes V (circularly polarized) profiles of an individual network patch in the quiet Sun observed by Sunrise/IMaX. At a spatial resolution of 0.15"-0.18", the network elements contain substructure which…

Faraday tomography of polarimetric observations at low frequency is a unique tool to study the structure of the magneto-ionic interstellar medium (ISM) based on Faraday depth. LOFAR data below 200 MHz revealed a plethora of features in…

We have conducted two pilot surveys for radio pulsars and fast transients with the Low-Frequency Array (LOFAR) around 140 MHz and here report on the first low-frequency fast-radio burst limit and the discovery of two new pulsars. The first…

The origins and generation mechanisms of the slow solar wind are still unclear. Part of the slow solar wind is populated by "number density structures", discrete patches of increased number density that are frozen in to and move with the…

Space Physics · Physics 2018-06-06 D. Stansby , T. S. Horbury

Quiet-Sun regions cover most of the Sun's surface; its magnetic fields contribute significantly to the solar chromospheric and coronal heating. However, characterizing the magnetic fields of the quiet Sun is challenging due to their weak…

Solar and Stellar Astrophysics · Physics 2024-12-02 Jiayi Liu , Xudong Sun , Peter W. Schuck , Sarah A. Jaeggli

The Nan\c{c}ay Radioheliograph (NRH) routinely produces snapshot images of the full sun at frequencies between 150 and 450 MHz, with typical resolution 3 arcmin and time cadence 0.2 s. Combining visibilities from the NRH and from the Giant…

Solar and Stellar Astrophysics · Physics 2015-06-23 Claude Mercier , Prasad Subramanian , Gilbert Chambe , P. Janardhan

We present numerical characterizations of the wavefront sensing performance for few-mode photonic lantern wavefront sensors (PLWFSs). These characterizations include calculations of throughput, control space, sensor linearity, and an…

Instrumentation and Methods for Astrophysics · Physics 2023-11-06 Jonathan Lin , Michael P. Fitzgerald , Yinzi Xin , Yoo Jung Kim , Olivier Guyon , Sergio Leon-Saval , Barnaby Norris , Nemanja Jovanovic

We present deep polarimetric observations at 1420 MHz of the European Large Area ISO Survey North 1 region (ELAIS N1) as part of the Dominion Radio Astrophysical Observatory Planck Deep Fields project. By combining closely spaced aperture…

Aims: Main goal of this work is to study the potential of He II Ly-alpha wavelength-integrated scattering polarisation for probing the magnetism of the solar upper chromosphere. Methods: Radiative transfer calculations are performed in…

Solar and Stellar Astrophysics · Physics 2024-08-14 F. Riva , G. Janett , L. Belluzzi

In Polarization Discrimination Imaging, the amplitude of a sinusoid from a rotating analyzer, representing residual polarized light and carrying information on the object, is detected with the help of a lock-in amplifier. When turbidity…

Image and Video Processing · Electrical Eng. & Systems 2019-11-05 Samudra Dasgupta , Jithun Nair , Shauryadipta Sarkar , Ram Mohan Vasu , Gargeshwari Venkatasubbiah Anand