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200 papers

Polar-ring galaxies are photometrically and kinematically decoupled systems which are highly inclined to the major axis of the host galaxy. These objects have been explored since the 1970s, but the rarity of these systems has made such…

We identified 97 strong pulsars from the NRAO VLA Sky Survey (NVSS) at 1.4 GHz north of Dec(J2000) $>-40\degr$. The total flux density, linear polarization intensity and polarization angle (PA) of all pulsars are extracted from the NVSS…

Astrophysics · Physics 2015-06-24 J. L. Han , W. W. Tian

The S-band Polarisation All-Sky Survey (S-PASS) has observed the entire southern sky using the 64-metre Parkes radio telescope at 2.3GHz with an effective bandwidth of 184MHz. The surveyed sky area covers all declinations $\delta\leq…

We present a pipeline that allows recovering reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the treatment of the instrumental effects already prior to the computation of the Stokes parameters…

Instrumentation and Methods for Astrophysics · Physics 2018-01-10 I. Myserlis , E. Angelakis , A. Kraus , C. A. Liontas , N. Marchili , M. F. Aller , H. D. Aller , V. Karamanavis , L. Fuhrmann , T. P. Krichbaum , J. A. Zensus

Aims. In this work we derive new precise and homogeneous parameters for 37 stars with planets. For this purpose, we analyze high resolution spectra obtained by the NARVAL spectrograph for a sample composed of bright planet host stars in the…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. G. Sousa , N. C. Santos , A. Mortier , M. Tsantaki , V. Adibekyan , E. Delgado Mena , G. Israelian , B. Rojas-Ayala , V. Neves

XPOL, the first correlation polarimeter at a large millimeter telescope, uses a flexible digital correlator to measure all four Stokes parameters simultaneously, i.e. the total power I, the linear polarization components Q and U, and the…

Astrophysics · Physics 2009-11-13 Clemens Thum , Helmut Wiesemeyer , Gabriel Paubert , Santiago Navarro , David Morris

The Vector Spectromagnetograph (VSM) instrument on the Synoptic Optical Long-term Investigations of the Sun (SOLIS) telescope is designed to obtain high-quality magnetic field observations in both the photosphere and chromosphere by…

Solar and Stellar Astrophysics · Physics 2015-07-30 Luca Bertello , Andrew R. Marble

The polarization of light is a critically under-utilized, rich source of information in astronomy. For stars in particular, surface magnetism polarization that can be detected and measured with spectro-polarimetry. Many questions about…

The regions around the celestial poles offer the ability to find and characterize long-term variables from ground-based observatories. We used multi-year Evryscope data to search for high-amplitude (~5% or greater) variable objects among…

An electromagnetic wave can be uniquely characterized by the four Stokes parameters: I, Q, U, and V. Typical observations in astronomy rely solely on total intensity measurements of the incoming radiation (Stokes I). However, a significant…

Astrophysics of Galaxies · Physics 2010-07-08 Jo-Anne C. Brown , Jeroen M. Stil , Tom L. Landecker

Polar faculae are bright features that can be detected in solar limb observations and they are related to magnetic field concentrations. Although there is a large number of works studying them, some questions about their nature as their…

Solar and Stellar Astrophysics · Physics 2016-05-25 C. Quintero Noda , Y. Suematsu , B. Ruiz Cobo , T. Shimizu , A. Asensio Ramos

High-cadence multi-band imaging and polarimetry have important scientific applications in astronomy. Observations of transits of exoplanets are a particular application that requires robust data reduction and analysis. We present the SPARC4…

An approach for measuring linear X-ray polarization over a broad-band using conventional spectroscopic optics is described. A set of multilayer-coated flats reflect the dispersed X-rays to the instrument detectors. The intensity variation…

Astrophysics · Physics 2009-11-13 Herman L. Marshall

Context. Polarimetric imaging is one of the most effective techniques for high-contrast imaging and characterization of protoplanetary disks, and has the potential to be instrumental in characterizing exoplanets. VLT/SPHERE contains the…

Taking advantage of the advances in array detector technology, an imaging polarimeter (IMPOL) has been constructed for measuring linear polarization in the wavelength band from 400-800 nm. It makes use of a Wollaston prism as the analyser…

Astrophysics · Physics 2009-09-15 A. N. Ramaprakash , Ranjan Gupta , A. K. Sen , S. N. Tandon

Synthetic spectra are needed to determine fundamental stellar and wind parameters of all types of stars. They are also used for the construction of theoretical spectral libraries helpful for stellar population synthesis. Therefore, a…

Solar and Stellar Astrophysics · Physics 2015-05-18 A. Palacios , M. Gebran , E. Josselin , F. Martins , B. Plez , M. Belmas , A. Lebre

We present an approach to spectropolarimetry which requires neither moving parts nor time dependent modulation, and which offers the prospect of achieving high sensitivity. The technique applies equally well, in principle, in the optical,…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 William Sparks , Thomas A. Germer , John MacKenty , Frans Snik

New linear polarization measurements (mainly in the V band) are presented for 203 quasi-stellar objects (QSOs). The sample is made up of 94 QSOs located in the North Galactic Pole (NGP) region and of 109 QSOs in the South Galactic Pole…

Astrophysics · Physics 2008-11-26 D. Sluse , D. Hutsemekers , H. Lamy , R. Cabanac , H. Quintana

High-resolution spectropolarimetry is a useful astronomical technique, in particular to study stellar magnetic fields. It has been extensively used in the past but mostly in the visible range. Space missions equipped with high-resolution…

Instrumentation and Methods for Astrophysics · Physics 2019-07-29 Maelle Le Gal , Martin Pertenais , Arturo Lopez Ariste , Coralie Neiner , Norbert Champion , Youssef Younes , Jean-Michel Reess

Linear polarized light has been used to view the solar corona for over 150 years. While the familiar Stokes representation for polarimetry is complete, it is best matched to a laboratory setting and therefore is not the most convenient…

Instrumentation and Methods for Astrophysics · Physics 2022-03-14 Craig E. DeForest , Daniel B. Seaton , Matthew J. West