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Related papers: Magnetic fields in X-ray emitting A-type stars

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We investigate the magnetic dichotomy between Ap/Bp and other A-type stars by carrying out a deep spectropolarimetric study of Am and HgMn stars. Using the NARVAL spectropolarimeter at the Telescope Bernard Lyot (Observatoire du Pic du…

Solar and Stellar Astrophysics · Physics 2015-05-19 M. Auriere , G. A. Wade , F. Lignieres , A. Hui-Bon-Hoa , J. D. Landstreet , I. Iliev , J. -F. Donati , P. Petit , T. Roudier , S. Theado

The phenomenology of the emission of pulsars and magnetars depends dramatically on the structure and properties of their magnetic field. In particular it is believed that the outbursting and flaring activity observed in AXPs and SRGs is…

High Energy Astrophysical Phenomena · Physics 2016-06-22 N. Bucciantini , A. G. Pili , L. Del Zanna

High-resolution X-ray spectra of high-mass stars and low-mass T-Tauri stars obtained during the first year of the Chandra mission are providing important clues about the mechanisms which produce X-rays on very young stars. For zeta Puppis…

Astrophysics · Physics 2007-05-23 Marc Gagne , David Cohen , Stanley Owocki , Asif Ud-Doula

Some main-sequence stars of spectral type A are observed to have a strong (300-30000 G), static, large-scale magnetic field, of a chiefly dipolar shape -- the `Ap stars' (for example Alioth, the fifth star in the Big Dipper). Following…

Astrophysics · Physics 2009-11-10 J. Braithwaite , H. C. Spruit

We review the current state of knowledge of magnetic fields inside stars, concentrating on recent developments concerning magnetic fields in stably stratified (zones of) stars, leaving out convective dynamo theories and observations of…

Solar and Stellar Astrophysics · Physics 2017-04-11 J. Braithwaite , H. C. Spruit

We present estimates of magnetic field in a number of AGNs from the Spectropolarimetric atlas of Smith, Young & Robinson (2002) from the observed degrees of linear polarization and the positional angles of spectral lines (H-alpha) (broad…

High Energy Astrophysical Phenomena · Physics 2015-06-04 N. A. Silant'ev , Yu. N. Gnedin , S. D. Buliga , M. Yu. Piotrovich , T. M. Natsvlishvili

X-ray pulsars (XRPs) are accreting strongly magnetised neutron stars (NSs) in binary systems with, as a rule, massive optical companions. Very reach phenomenology and high observed flux put them into the focus of observational and…

High Energy Astrophysical Phenomena · Physics 2023-04-27 Alexander Mushtukov , Sergey Tsygankov

We explore the empirical power-law relationship between X-ray luminosity (Lx) and total surface magnetic flux (Phi), established across solar magnetic elements, time- and disk-averaged emission from the Sun, older active stars, and…

High magnetic fields are a distinguishing feature of neutron stars and the existence of sources (the soft gamma repeaters and the anomalous X-ray pulsars) hosting an ultra-magnetized neutron star (or magnetar) has been recognized in the…

Astrophysics of Galaxies · Physics 2012-07-11 Nanda Rea , Jose' A. Pons , Diego F. Torres , Roberto Turolla

Developments over the last couple of years have supported the interpretation that anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) possess unusually high magnetic fields, and furthermore may represent a class or classes of…

Astrophysics · Physics 2007-05-23 Matthew G. Baring , Alice K. Harding

High-dispersion, archival spectra of magnetic Ap stars with resolved Zeeman components in Stokes I are used to derive a simple relation that can be utilised to estimate the mean surface field strengths of stars with v sin i > 10 km/s. For…

Solar and Stellar Astrophysics · Physics 2014-09-05 J. D. Bailey

Anomalous X-ray pulsars (AXPs) are slowly rotating neutron stars with very bright and highly variable X-ray emission that are believed to be powered by ultra-strong magnetic fields of >1e14 G, according to the 'magnetar' model. The radio…

Many observations of late-type M stars show large near-spherical circumstellar envelopes, yet planetary nebulae and supernova remnants are frequently axisymmetric. We present VLBI and MERLIN observations of masers around the red supergiant…

Studying the magnetic fields of exoplanets will provide valuable information about their interior structures, atmospheric properties (escape and dynamics), and potential habitability. One of the most promising methods to detect exoplanetary…

We have studied the magnetic field of about 50 active and non-active single G-K-type red giants by means of spectropolarimetry with Narval and ESPaDOnS. 30 giants have been significantly Zeeman-detected. A close study of the 17 giants with…

Solar and Stellar Astrophysics · Physics 2013-10-28 M. Auriere , F. Lignieres , R. Konstantinova-Antova , C. Charbonnel , P. Petit , S. Tsvetkova , G. A. Wade

The magnetar model and a solid quark star model for anomalous X-ray pulsars/soft gamma-ray repeaters (AXPs/SGRs) are discussed. Different manifestations of pulsar-like stars are speculated to be due to both their nature (e.g., mass and…

Astrophysics · Physics 2008-11-26 Renxin Xu

The anomalous X-ray pulsars and soft gamma-repeaters are peculiar high-energy sources believed to host a magnetar, i.e. an ultra-magnetized neutron star. Their persistent, soft X-ray emission (~1-10 keV)is usually modeled by the…

Astrophysics · Physics 2009-11-13 L. Nobili , R. Turolla , S. Zane

Recent low-frequency array (LOFAR) radio signal detections bearing from the $\tau$ Bo\"otis system have been cautiously attributed to auroral emissions from the hot Jupiter $\tau$ Bo\"otis Ab. The auroral emissions are believed to be…

Earth and Planetary Astrophysics · Physics 2025-11-21 Dag Evensberget , Aline A. Vidotto , Filip Elekes , Sandra V. Jeffers , Rik T. Luisman

Evidence from the analysis of eclipsing binary systems revealed that late-type stars are larger and cooler than predicted by models, and that this is probably caused by stellar magnetic activity. In this work, we revisit this problem taking…

Solar and Stellar Astrophysics · Physics 2022-12-13 J. C. Morales , I. Ribas , Á. Giménez , D. Baroch

The hard X-ray emission from magnetars and other isolated neutron stars remains under-explored. An instrument with higher sensitivity to hard X-rays is critical to understanding the physics of neutron star magnetospheres and also the…