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Khomenko et al. estimate the mean magnetic field strength of the quiet Sun to be 20 G. The figure is smaller than several existing estimates, and it comes from the comparison between observed Zeeman polarization signals and synthetic…

天体物理学 · 物理学 2009-11-11 J. Sanchez Almeida

In a microlensing event, a large magnification occurs at caustic crossing and provides an opportunity to obtain a stronger signal associated with the object. In this paper we study the possibility of magnetic field detection in a…

太阳与恒星天体物理 · 物理学 2015-08-04 Ahmad Mehrabi , Habib khosroshahi , Hadi Rahmani

We have observed the OH (1720 MHz) line in five galactic SNRs with the VLA to measure their magnetic field strengths using the Zeeman effect. We detected all 12 of the bright ($S_{\nu} > 200$ mJy) OH (1720 MHz) masers previously detected by…

天体物理学 · 物理学 2009-10-31 C. L. Brogan , D. A. Frail , W. M. Goss , T. H. Troland

In solar physics, it is a big challenge to measure the magnetic fields directly from observations in the upper solar atmosphere, including the chromosphere and corona. Radio observations are regarded as the most feasible approach to…

太阳与恒星天体物理 · 物理学 2022-06-22 Baolin Tan

In this study we explore the diagnostic potential of the chromospheric Ca II line at 8542A for studying the magnetic and dynamic properties of solar filaments. We have acquired high spatial resolution spectropolarimetric observations in the…

太阳与恒星天体物理 · 物理学 2019-04-03 C. J. Díaz Baso , M. J. Martínez González , A. Asensio Ramos , J. de la Cruz Rodríguez

We study the quiet Sun magnetic fields using spectropolarimetric observations of the infrared and visible Fe I lines at 6301.5, 6302.5, 15648 and 15653 A. Magnetic field strengths and filling factors are inferred by the simultaneous fit of…

天体物理学 · 物理学 2008-11-26 Itahiza Dominguez Cerdena , Jorge Sanchez Almeida , Franz Kneer

The magnetic field of the quiet-Sun chromosphere remains a mystery for solar physicists. The reduced number of chromospheric lines are intrinsically hard to model and only a few of them are magnetically sensitive. In this work, we use a 3D…

太阳与恒星天体物理 · 物理学 2012-03-22 J. de la Cruz Rodríguez , H. Socas-Navarro , M. Carlsson , J. Leenaarts

We employ the magnetic and velocity fields from turbulent dynamo simulations to synthesize the polarization of a typical photospheric line. The synthetic Stokes profiles have properties in common with those observed in the quiet Sun. The…

天体物理学 · 物理学 2009-11-07 J. Sánchez Almeida , T. Emonet , F. Cattaneo

We present an XMM-Newton spectrum of diffuse X-ray emission from within the solar system. The spectrum is dominated by probable C VI lines at 0.37 keV and 0.46 keV, an O VII line at 0.56 keV, O VIII lines at 0.65 keV and ~0.8 keV, Ne IX…

天体物理学 · 物理学 2009-11-10 S. L. Snowden , M. R. Collier , K. D. Kuntz

We report novel spectropolarimetric observations of sunspots carried out with the Tenerife Infrared Polarimeter (TIP) in a near-IR spectral region around 15410 A, which is known to contain two groups of prominent OH lines that show circular…

天体物理学 · 物理学 2009-11-11 A. Asensio Ramos , J. Trujillo Bueno , M. Collados

Magnetic field in the solar lower atmosphere can be measured by the use of the Zeeman and Hanle effects. In contrast, the coronal magnetic field well above the solar surface, which directly controls various eruptive phenomena, can not be…

太阳与恒星天体物理 · 物理学 2010-01-05 P. F. Chen

The angular power spectrum of the SZ effect, C_l, is a powerful probe of cosmology. It is easier to detect than individual clusters in the field, is insensitive to observational selection effects and does not require a calibration between…

天体物理学 · 物理学 2009-11-07 Eiichiro Komatsu , Uros Seljak

Dynamos in the Sun and other bodies tend to produce magnetic fields that possess magnetic helicity of opposite sign at large and small scales, respectively. The build-up of magnetic helicity at small scales provides an important saturation…

太阳与恒星天体物理 · 物理学 2010-11-30 Piyali Chatterjee , Gustavo Guerrero , Axel Brandenburg

Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously…

太阳与恒星天体物理 · 物理学 2020-11-05 Zihao Yang , Hui Tian , Steven Tomczyk , Richard Morton , Xianyong Bai , Tanmoy Samanta , Yajie Chen

The determination of the magnetic filed vector in solar filaments is possible by interpreting the Hanle and Zeeman effects in suitable chromospheric spectral lines like those of the He I multiplet at 10830 A. We study the vector magnetic…

太阳与恒星天体物理 · 物理学 2019-05-29 C. J. Díaz Baso , M. J. Martínez González , A. Asensio Ramos

The Delta a photometric system provides an efficient observational method to identify and distinguish magnetic and several other types of chemically peculiar (CP) stars of spectral types B to F from other classes of stars in the same range…

天体物理学 · 物理学 2009-11-07 F. Kupka , E. Paunzen , H. M. Maitzen

We propose a method to derive the line-of-sight magnetic flux density from measurements in the chromospheric Ca II IR line at 854.2 nm. The method combines two well-understood techniques, the center-of-gravity and bisector methods, in a…

太阳与恒星天体物理 · 物理学 2009-12-18 F. Wöger , S. Wedemeyer-Böhm , H. Uitenbroek , T. Rimmele

The small DAHe and DAe spectral classes comprise isolated, hydrogen-dominated atmosphere white dwarfs that exhibit variable photometric flux and Balmer line emission. These mysterious systems offer unique insight into the complex interplay…

First results from a study of high ionization absorption properties in roughly 30 Mg II absorption selected galaxies are presented. We have tested for correlations of Mg II, C IV, Si IV, N V, and O VI equivalent widths with the galaxy…

天体物理学 · 物理学 2008-02-03 Christopher W. Churchill

We present further observational evidence in support of our earlier proposal (Houde et al. 2000) for detecting the presence of the magnetic field in molecular clouds by comparing spectra of molecular ions with those of neutral molecules.…

天体物理学 · 物理学 2009-11-10 Martin Houde , Ruisheng Peng , Thomas G. Phillips , Pierre Bastien , Hiroshige Yoshida
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