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We describe the POLAMI program for the monitoring of all four Stokes parameters of a sample of bright radio-loud active galactic nuclei with the IRAM 30m telescope at 3.5 and 1.3mm. The program started in October 2006 and accumulated, until…

Direct measurements of magnetic fields in low-mass stars of spectral class M have become available during the last years. This contribution summarizes the data available on direct magnetic measurements in M dwarfs from Zeeman analysis in…

Solar and Stellar Astrophysics · Physics 2009-11-13 Ansgar Reiners

We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star), in the context of the Magnetism in Massive Stars…

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…

Solar and Stellar Astrophysics · Physics 2020-04-21 T. del Pino Alemán , J. Trujillo Bueno , R. Casini , R. Manso Sainz

A single measurement of linear polarization of a nonthermal source provides direct information about the mean direction and level of ordering of the magnetic field. Monitoring of the polarization in blazars, combined with millimeter-wave…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Alan P. Marscher

We have analysed the photometric data obtained with the STEREO spacecraft for 558 non-magnetic chemically peculiar (CP) stars to search for rotational and pulsational variability. Applying the Lomb-Scargle and the phase dispersion…

Solar and Stellar Astrophysics · Physics 2015-06-12 E. Paunzen , K. T. Wraight , L. Fossati , M. Netopil , G. J. White , D. Bewsher

Very little is known about the polarimetric properties of CH stars and carbon-enhanced metal-poor (CEMP) stars, although many of these objects have been studied in detail both photometrically and spectroscopically. We aim to derive…

Solar and Stellar Astrophysics · Physics 2015-06-12 Aruna Goswami , Drisya Karinkuzhi

AU Mic is a young, very active M dwarf star with a debris disk and at least one transiting Neptune-size planet. Here we present detailed analysis of the magnetic field of AU Mic based on previously unpublished high-resolution optical and…

Solar and Stellar Astrophysics · Physics 2020-10-21 Oleg Kochukhov , Ansgar Reiners

Polaris is a highly unusual Cepheid with observed properties that are difficult to reconcile with stellar evolutionary models. Since the initial detection of Polaris' magnetic field in 2020, we have conducted a magnetic monitoring campaign…

Solar and Stellar Astrophysics · Physics 2026-03-13 James A. Barron , Gregg A. Wade , Colin P. Folsom

Aims. The very weak magnetic field detected at the surface of Vega hints at a widespread population of weakly magnetic stars of A and B spectral types. We contribute here to gather more clues about the origin of this magnetism by…

Solar and Stellar Astrophysics · Physics 2022-10-05 P. Petit , T. Böhm , C. P. Folsom , F. Lignières , T. Cang

Light scattered off particles can become linearly polarized. Stars surrounded by oblique, co-rotating envelopes are therefore expected to manifest periodic linear polarimetric variations. The electron scattering magnetospheres of magnetic…

Solar and Stellar Astrophysics · Physics 2022-01-05 M. S. Munoz , G. A. Wade , D. M. Faes , A. C. Carciofi , J. Labadie-Bartz

The POLISH2 optical polarimeter has been in operation at the Lick Observatory 3-m Shane telescope since 2011, and it was commissioned at the Gemini North 8-m in 2016. This instrument primarily targets exoplanets, asteroids, and the Crab…

We investigate a region of the quiet solar photosphere exhibiting three-lobed Stokes V profiles in the Fe I spectral line at 15648 Angstroem. The data were acquired with the GRIS spectropolarimeter attached to the GREGOR telescope. We aim…

Solar and Stellar Astrophysics · Physics 2018-08-29 Christoph Kiess , Juan Manuel Borrero , Wolfgang Schmidt

We present the first short time scale observations of the roAp star gamma Equ in linear polarized light obtained with the PEPSI polarimeter installed at the LBT. These observations are used to search for pulsation variability in Stokes Q…

Solar and Stellar Astrophysics · Physics 2021-09-01 S. Hubrig , S. P. Jarvinen , I. Ilyin , K. G. Strassmeier , M. Schöller

We present the analysis performed on spectropolarimetric data of 97 O-type targets included in the framework of the MiMeS (Magnetism in Massive Stars) Survey. Mean Least-Squares Deconvolved Stokes I and V line profiles were extracted for…

The nature of non-variable high-excitation emission lines detected in the optical spectra of normal late-B type and chemically peculiar HgMn and PGa stars is still poorly understood. To better understand the origin of the weak emission…

Astrophysics · Physics 2009-11-13 S. Hubrig , J. F. Gonzalez

New spectral line polarisation observations of 7 bright Ap stars have been obtained with the ESPaDOnS and Narval high resolution spectropolarimeters (Silvester et al. 2012). The aim of this data set is produce a series of surface magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-17 J. Silvester , O. Kochukhov , G. A. Wade

To investigate if magnetic fields are present in Wolf-Rayet stars, we selected a few stars in the Galaxy and one in the Large Magellanic Cloud (LMC). We acquired low-resolution spectropolarimetric observations with the ESO FORS2 instrument…

Solar and Stellar Astrophysics · Physics 2016-03-23 S. Hubrig , K. Scholz , W. -R. Hamann , M. Schoeller , R. Ignace , I. Ilyin , K. G. Gayley , L. M. Oskinova

We present on-sky polarimetric observations with the Gemini Planet Imager (GPI) obtained at straight Cassegrain focus on the Gemini South 8-m telescope. Observations of polarimetric calibrator stars, ranging from nearly unpolarized to…

A Doppler image of the ZAMS late-type rapidly rotating star LO Pegasi, based on spectra acquired between 12 and 15 September 2003, is presented. The Least Square Deconvolution technique is applied to enhance the signal-to-noise ratio of the…

Astrophysics · Physics 2009-11-13 N. Piluso , A. F. Lanza , I. Pagano , A. C. Lanzafame , J. -F. Donati