English
Related papers

Related papers: DKIST resolves sub-arcsec photospheric scattering …

200 papers

We present the first degree-scale tomography map of the dusty magnetized interstellar medium (ISM) from stellar polarimetry and distance measurements. We used the RoboPol polarimeter at Skinakas Observatory to conduct a survey of starlight…

We derive exact expressions for the degree of lineal polarization over a resolved or integrated stellar disc due to resonance scattering and the Hanle effect from a dipolar or quadrupolar distribution of magnetic fields. We apply the theory…

Solar and Stellar Astrophysics · Physics 2015-06-11 R. Manso Sainz , M. J. Martínez González

This paper presents a theoretical investigation on the polarization and magnetic sensitivity of the near-ultraviolet (near-UV) solar spectral lines of Fe II between 250 and 278 nm. In recent years, UV spectropolarimetry has become key to…

Solar and Stellar Astrophysics · Physics 2023-05-17 David Afonso Delgado , Tanausú del Pino Alemán , Javier Trujillo Bueno

Searches for small exoplanets around solar-type stars are limited by stellar physical variability. While chromospheric variability is well studied, observing, modeling. and understanding the much smaller fluctuations in photospheric…

Solar and Stellar Astrophysics · Physics 2024-07-03 Dainis Dravins , Hans-Günter Ludwig

High spatial resolution spectro-polarimetric observation of a decaying spot was observed with the Diffraction Limited Spectro-Polarimeter. The spatial resolution achieved was close to the diffraction limit (0."18) of the Dunn Solar…

Astrophysics · Physics 2008-01-21 K. Sankarasubramanian , H. Hagenaar

We report on spectropolarimetric observations of a near-IR line of Mn I located at 15262.702 A whose intensity and polarization profiles are very sensitive to the presence of hyperfine structure. A theoretical investigation of the magnetic…

The strongly coupled hydrodynamic, magnetic, and radiation properties of the plasma in the solar chromosphere makes it a region of the Sun's atmosphere that is poorly understood. We use data obtained with the high-resolution Visible…

Quiet-Sun regions cover most of the Sun's surface; its magnetic fields contribute significantly to the solar chromospheric and coronal heating. However, characterizing the magnetic fields of the quiet Sun is challenging due to their weak…

Solar and Stellar Astrophysics · Physics 2024-12-02 Jiayi Liu , Xudong Sun , Peter W. Schuck , Sarah A. Jaeggli

Polarization at millimeter wavelengths provides a powerful diagnostic of dust grain properties in protoplanetary disks. Standard models based on solid spherical grains often struggle to reproduce the observed polarization fractions and…

Polarized (sub)millimeter emission from dust grains in circumstellar disks was initially thought to be due to grains aligned with the magnetic field. However, higher resolution multi-wavelength observations along with improved models found…

The Hanle effect in strong spectral lines is the physical mechanism that should be increasingly exploited for quantitative explorations of the magnetism of the quiet solar chromospheric plasma. Here we show, by means of multilevel radiative…

Solar and Stellar Astrophysics · Physics 2011-02-25 Jiri Stepan , Javier Trujillo Bueno , Renzo Ramelli , Michele Bianda

Magnetic fields grown by instabilities driven by differential rotation are believed to be essential to accretion onto black holes. These instabilities saturate in a turbulent state; therefore, the spatial and temporal variability in the…

Instrumentation and Methods for Astrophysics · Physics 2022-12-07 Chunchong Ni , Avery E. Broderick , Roman Gold

Spatially resolved polarized millimeter/submillimeter emission has been observed in the disk of HL Tau and two other young stellar objects. It is usually interpreted as coming from magnetically aligned grains, but can also be produced by…

Solar and Stellar Astrophysics · Physics 2018-10-16 Haifeng Yang , Zhi-Yun Li , Leslie Looney , Ian Stephens

The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a suborbital rocket experiment that on 3rd September 2015 measured the linear polarization produced by scattering processes in the hydrogen Ly-$\alpha$ line of the solar disk…

The Southern Galactic Plane Survey (SGPS) is an HI and 1.4-GHz continuum survey of the 4th quadrant of the Galaxy at arcmin resolution. We present here results on linearly polarized continuum emission from an initial 28-square-degree Test…

Recent observation of linear optical polarization from brown dwarfs confirms the dust hypothesis in the atmospheres of brown dwarfs with effective temperature higher than 1400 K. The observed polarization could arise due to dust scattering…

Astrophysics · Physics 2009-11-07 Sujan Sengupta

Radio pulsars, as highly coherent point sources, serve as powerful probes of the ionized interstellar medium (IISM). Pulsar scintillation observations have revealed inverted arclets on the secondary spectrum, indicating quasilinearly…

Astrophysics of Galaxies · Physics 2026-04-14 Zhu Xu , Xun Shi

We performed the new JVLA full polarization observations at 40-48 GHz (6.3-7.5 mm) towards the nearby ($d$ $=$147$\pm$3.4 pc) Class 0 YSO IRAS 16293-2422, and compare with the previous SMA observations reported by Rao et al. (2009; 2014).…

Astrophysics of Galaxies · Physics 2018-09-19 Hauyu Baobab Liu , Yasuhiro Hasegawa , Tao-Chung Ching , Shih-Ping Lai , Naomi Hirano , Ramprasad Rao

Polarimetric radio observations of the Sun can provide rich information about emission mechanisms and the propagation medium. For the past five decades, solar polarimetric studies at low radio frequencies have almost always assumed the…

Solar and Stellar Astrophysics · Physics 2025-08-05 Soham Dey , Devojyoti Kansabanik , Divya Oberoi , Surajit Mondal

Using full-wave numerical simulations and analytical multipole expansions we investigated the properties of real-space polarization singularities that emerge in light scattering by subwavelength particles. We considered spherical and torus…

Optics · Physics 2021-02-18 Jie Peng , Wei Liu , Shubo Wang