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We study a granular-sized magnetic flux emergence event that occurred in NOAA 11024 in July 2009. The observations were made with the CRISP spectropolarimeter at the Swedish 1 m Solar Telescope achieving a spatial resolution of 0.14".…

Solar and Stellar Astrophysics · Physics 2015-06-18 Ada Ortiz , Luis Bellot Rubio , Viggo Hansteen , Jaime de la Cruz Rodriguez , Luc Rouppe van der Voort

Solar active regions show a wide variety of oscillatory phenomena. The presence of the magnetic field leads to the appearance of several wave modes, whose behavior is determined by the sunspot thermal and magnetic structure. We aim to study…

Solar and Stellar Astrophysics · Physics 2019-01-09 T. Felipe , C. Kuckein , E. Khomenko , I. Thaler

We present proper motions obtained from a dual frequency, six-epoch, VLBA polarization experiment monitoring a sample of 12 blazars. The observations were made at 15 GHz and 22 GHz at bi-monthly intervals over 1996. Ten of the eleven…

Astrophysics · Physics 2009-10-31 D. C. Homan , R. Ojha , J. F. C. Wardle , D. H. Roberts , M. F. Aller , H. D. Aller , P. A. Hughes

We present results of the study of chromospheric and photospheric line-of-sight velocity fields in the young active region NOAA 11024. Multi-layer, multi-wavelength observational data were used for the analysis of the emerging flux in this…

Solar and Stellar Astrophysics · Physics 2012-12-07 N. N. Kondrashova , M. N. Pasechnik , S. N. Chornogor , E. V. Khomenko

Based on observations obtained with the Solar and Heliospheric Observatory - SOHO joint observing program for velocity fields in sunspot regions, we have detected 3 min transition region umbral oscillations in NOAA 8156. Simultaneous…

Astrophysics · Physics 2009-10-31 N. Brynildsen , T. Leifsen , O. Kjeldseth-Moe , P. Maltby , K. Wilhelm

In this paper we analyse the methodology to derive the bar pattern speed from dynamical simulations. The results are robust to the changes in the vertical-scale height and in the mass-to-light (M/L) ratios. There is a small range of…

Astrophysics of Galaxies · Physics 2010-02-08 I. Perez , K. C. Freeman , R. Fux , A. Zurita

Context. Bright points (BPs) are small-scale, magnetic features ubiquitous across the solar surface. Previously, we have observed and noted their properties for quiet Sun regions. Here, we determine the dynamic properties of BPs using…

Solar and Stellar Astrophysics · Physics 2014-07-02 Peter H. Keys , Mihalis Mathioudakis , David B. Jess , Duncan H. Mackay , Francis P. Keenan

High-resolution spectropolarimetric observations of active region NOAA 11271 were obtained with the spectro-polarimeter on board Hinode to analyze the properties of an anomalous flow in the photosphere in a sunspot penumbra. We detect a…

Solar and Stellar Astrophysics · Physics 2014-10-29 Rohan E. Louis , Christian Beck , Shibu K. Mathew , P. Venkatakrishnan

Sunspot observations in chromospheric spectral lines have revealed the existence of short-lived linear bright transients, commonly referred to as penumbral micro-jets (PMJs). Details on the origin and physical nature of PMJs are to large…

Solar and Stellar Astrophysics · Physics 2019-06-19 Luc Rouppe van der Voort , Ainar Drews

The magnetic geometry of the solar atmosphere, combined with projection effects, makes it difficult to accurately map the propagation of ubiquitous waves in fibrillar structures. These waves are of interest due to their ability to carry…

Helioseismic and magnetohydrodynamic waves are abundant in and above sunspots. Through cross-correlating oscillation signals in the photosphere observed by the SDO/HMI, we reconstruct how waves propagate away from virtual wave sources…

Solar and Stellar Astrophysics · Physics 2015-08-19 Junwei Zhao , Ruizhu Chen , Thomas Hartlep , Alexander G. Kosovichev

Solar flare ribbons are features in the lower atmosphere that show enhanced emission intensity, particularly noticeable in H$\alpha$ and EUV images of the transition region and upper chromosphere. In this study, we provide observational…

NRAO 150 -a compact and bright radio to mm source showing core/jet structure- has been recently identified as a quasar at redshift z=1.52 through a near-IR spectral observation. To study the jet kinematics on the smallest accessible scales…

Context: Except for the Ca II resonance lines, fibrils are ubiquitously present in most high-resolution observations of chromospheric lines. Aims: We show that fibrils are also a prevailing feature in Ca II K, provided the…

Solar and Stellar Astrophysics · Physics 2015-05-13 A. Pietarila , J. Hirzberger , V. Zakharov , S. K. Solanki

We report a chromospheric jet lasting for more than 1 hr observed by Hinode Solar Optical Telescope in unprecedented detail. The ejection occurred in three episodes separated by 12-14 min, with the amount and velocity of material decreasing…

Solar and Stellar Astrophysics · Physics 2012-08-17 Wei Liu , Thomas E. Berger , Alan M. Title , Theodore D. Tarbell

We present a statistical study of prominence and filament eruptions observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). Several properties are recorded for 904 events that were culled from the…

Solar and Stellar Astrophysics · Physics 2015-05-11 Patrick I. McCauley , Yingna Su , Nicole Schanche , Kaitlin E. Evans , Chuan Su , Sean McKillop , Katharine K. Reeves

Peculiar motion of the solar system, determined from the dipole anisotropy in the Cosmic Microwave Background Radiation (CMBR), has given a velocity $370$ km s$^{-1}$ along RA$=168^{\circ}$, Dec$=-7^{\circ}$. Subsequent peculiar motion…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-04 Ashok K. Singal

We report the discovery and characterization of high-speed (>100 km/s) horizontal flows in solar active regions, making use of the Sun-as-a-star spectroscopy in the range 5-105 nm provided by the EVE (Extreme Ultraviolet Variability…

Spirals are common in Nature: the snail's shell and the ordering of seeds in the sunflower are amongst the most widely-known occurrences. While these are static, dynamic spirals can also be observed in excitable systems such as heart…

Dynamical Systems · Mathematics 2007-05-23 Patrick Boily