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The observing signals from pulsar are always influenced by the interstellar medium (ISM) scattering. In the lower frequency observation, the intensity profiles are broadened and the plane of polarization angle (PPA) curves are flattened by…

太阳与恒星天体物理 · 物理学 2015-06-16 Abdujappar Rusul , Ali Esamdin , Xiao-Ping Zheng , Jian-Ping Yuan

Context. The spatially coherent multipath propagation of pulsar radiation leads to a temporal and spectral interference patterns called scintillation. It is caused by density variations in the ionized interstellar medium, which often take…

高能天体物理现象 · 物理学 2026-05-15 Tim Sprenger , Xun Shi , Olaf Wucknitz , Robert A. Main

We highlight the main results of a three-dimensional (3D) multilevel radiative transfer investigation about the solar disk-center polarization of the Ca {\sc ii} 8542 \AA\ line. First, we investigate the linear polarization due to the…

太阳与恒星天体物理 · 物理学 2016-07-27 Jiří Štěpán , Javier Trujillo Bueno

In this work we study variations in the parabolic scintillation arcs of the binary millisecond pulsar PSR J1643-1224 over five years using the Large European Array for Pulsars (LEAP). The 2D power spectrum of scintillation, called the…

Using radiative magneto-hydrodynamic simulations of the magnetised solar photosphere and detailed spectro-polarimetric diagnostics with the FeI $6301.5\mathrm{\AA}$ and $6302.5\mathrm{\AA}$ photospheric lines in the local thermodynamic…

太阳与恒星天体物理 · 物理学 2015-06-23 S. Shelyag

Synchrotron radiation from active galactic nuclei (AGN) is often highly polarized. We present a search for linear polarization with the Very Large Array (VLA) at 4.8 GHz and 8.4 GHz from the nearest AGN, Sagittarius A*. As a part of this…

天体物理学 · 物理学 2009-10-31 Geoffrey C. Bower , Donald C. Backer , Jun-Hui Zhao , Miller Goss , Heino Falcke

We present spectropolarimetric observations of the nearby Type Ia SN 2014J in M82 over six epochs: +0, +7, +23, +51, +77, +109, and +111 days with respect to B-band maximum. The strong continuum polarization, which is constant with time,…

We measured the linear polarization of Sagittarius A* to be 7.2 +/- 0.6 % at 230 GHzusing the BIMA array with a resolution of 3.6 x 0.9 arcsec. This confirms the previously reported detection with the JCMT 14-m antenna. Our high resolution…

天体物理学 · 物理学 2008-11-26 Geoffrey C. Bower , Melvyn C. H. Wright , Heino Falcke , Donald C. Backer

An increasing number of young circumstellar disks show strikingly ordered (sub)millimeter polarization orientations along the minor axis, which is strong evidence for polarization due to scattering by ~0.1 mm sized grains. To test this…

地球与行星天体物理 · 物理学 2020-06-10 Zhe-Yu Daniel Lin , Zhi-Yun Li , Haifeng Yang , Leslie Looney , Ian Stephens , Charles L. H. Hull

We studied the turbulence spectrum of the local interstellar plasma in the direction of PSR J0437-4715, on the basis of our observations and those reported earlier by others. We combine these data to form a structure function for the…

天体物理学 · 物理学 2009-11-11 T. V. Smirnova , C. R. Gwinn , V. I. Shishov

The turbulent nature of the ionised interstellar medium (IISM) causes dispersion measure (DM) and scattering variations in pulsar timing measurements. To improve precision of gravitational wave measurements, pulsar timing array (PTA)…

高能天体物理现象 · 物理学 2025-11-06 A. D. Kulkarni , R. M. Shannon , D. J. Reardon , M. T. Miles

A very slight rotation-induced latitudinal temperature variation (presumably on the order of several Kelvin) on the solar surface is theoretically expected. While recent high-precision solar brightness observations reported its detection,…

太阳与恒星天体物理 · 物理学 2017-08-30 Y. Takeda , S. UeNo

The detection of suspended single particles (SSPs) in water is a crucial element for monitoring water ecosystems. Although there are a variety of sensory methods, it is still an unrealized goal to combine multi-wavelength polarized light…

光学 · 物理学 2024-10-31 Tong Liu

Aims: We investigate how well modeled solar irradiances agree with measurements from the SORCE satellite, both for total solar irradiance and broken down into spectral regions on timescales of several years. Methods: We use the SATIRE model…

太阳与恒星天体物理 · 物理学 2015-05-27 Will T. Ball , Yvonne C. Unruh , Natalie A. Krivova , Sami Solanki , Jerald W. Harder

Polarimetric studies of light transmitted through interstellar clouds may give constraints on the properties of the interstellar dust grains. Traditionally, broadband linear polarisation (BBLP) measurements have been considered an important…

Radio images of the Galactic Center supermassive black hole, Sagittarius A* (Sgr A*), are dominated by interstellar scattering. Previous studies of Sgr A* have adopted an anisotropic Gaussian model for both the intrinsic source and the…

Scattering polarization tends to dominate the linear polarization signals of the Ca II 8542 A line in weakly magnetized areas ($B \lesssim 100$ G), especially when the observing geometry is close to the limb. In this paper we evaluate the…

太阳与恒星天体物理 · 物理学 2021-09-08 Rebecca Centeno , Jaime de la Cruz Rodriguez , Tanausu del Pino Aleman

Aims: We test the reliability of the observed and calculated spectral irradiance variations between 200 and 1600 nm over a time span of three solar rotations in 2004. Methods: We compare our model calculations to spectral irradiance…

天体物理学 · 物理学 2009-11-13 Yvonne C. Unruh , Natalie A. Krivova , Sami K. Solanki , Jerald W. Harder , Greg Kopp

We present multilevel radiative transfer modeling of the scattering polarization observed in the solar O I infrared triplet around 777 nm. We demonstrate that the scattering polarization pattern observed on the solar disk forms in the…

太阳与恒星天体物理 · 物理学 2015-08-06 T. del Pino Alemán , J. Trujillo Bueno

We present far ultraviolet (FUV: 912 - 1750AA) spectral imaging observations recorded with the SPEAR satellite of the interstellar OVI (1032AA), CIV (1550AA), SiIV (1394AA), SiII* (1533AA) and AlII (1671AA) emission lines originating in a…

天体物理学 · 物理学 2009-11-13 B. Y. Welsh , J. Edelstein , E. Korpela