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The resonance lines of \ion{Si}{4} formed at $\lambda$1394 and 1403 {\AA} are the most critical for the diagnostics of the solar transition region in the observations of the Interface Region Imaging Spectrograph (IRIS). Studying the…

Solar and Stellar Astrophysics · Physics 2020-05-20 Durgesh Tripathi , V. N. Nived , Hiroaki Isobe , J. G. Doyle

Context. An analysis of the oscillations above sunspots was carried out using simultaneous ground-based and Solar Dynamics Observatory (SDO) observations (SiI 10827A, HeI 10830A, FeI 6173A, 1700A, HeII 304A, FeIX 171A). Aims. Investigation…

Solar and Stellar Astrophysics · Physics 2014-11-25 N. I. Kobanov , A. A. Chelpanov , D. Y. Kolobov

Sunspot penumbrae show a fine structure in continuum intensity that displays considerable dynamics. The magnetic field, in contrast, although also highly structured, has appeared to be relatively static. Here we report the discovery of…

Astrophysics · Physics 2009-11-13 Jun Zhang , S. Solanki , J. Woch

The inverse Evershed flow (IEF) is an inflow of material into the penumbra of sunspots in the solar chromosphere that occurs along dark, elongated superpenumbral fibrils extending from about the outer edge of the moat cell to the sunspot.…

Solar and Stellar Astrophysics · Physics 2020-03-18 C. Beck , D. P. Choudhary

We present high angular resolution ($2\rlap.{''}8 \times 1\rlap.{''}7$) SiO J=5$\to$4; $v=0$ line observations of the OMC1S region in the Orion Nebula made using the Submillimeter Array (SMA). We detect for the first time a cluster of four…

We perform a high-cadence transient survey with Subaru Hyper Suprime-Cam (HSC), which we call the Subaru HSC survey Optimized for Optical Transients (SHOOT). We conduct HSC imaging observations with time intervals of about one hour on two…

Short abstract: We present fully 3-D simulations of supersonic, radiatively cooling intermittent jets with intermediate and long variability periods (that is, periods of the order of or longer than, the dynamical time scale of the jet).…

Astrophysics · Physics 2009-10-22 E. M. de Gouveia Dal Pino , W. Benz

We present a 106-minute TiO (705.7nm) time series of high spatial and temporal resolution that contains thousands of umbral dots (UDs) in a mature sunspot in the active region NOAA 10667 at $\mu$=0.95. The data were acquired with the 1-m…

Astrophysics · Physics 2008-12-03 T. L. Riethmueller , S. K. Solanki , V. Zakharov , A. Gandorfer

We have measured the meridional motions of the magnetic elements in the Sun's surface layers since 1996 and find systematic and substantial variations. In general the meridional flow speed is fast at cycle minima and slow at cycle maxima.…

Solar and Stellar Astrophysics · Physics 2015-06-19 David H. Hathaway , Lisa Upton

We present the properties of the inverse Evershed flow (IEF) based on the center-to-limb variation of the plasma speed and loop geometry of chromospheric superpenumbral fibrils in eleven sunspots that were located at a wide range of…

Solar and Stellar Astrophysics · Physics 2020-10-14 C. Beck , D. P. Choudhary , M. Ranganathan

The increased amount of information provided by ongoing missions such as the Solar Dynamics Observatory (SDO) represents a great challenge for the understanding of basic questions such as the internal structure of sunspots and how they…

Solar and Stellar Astrophysics · Physics 2013-10-29 R. Gafeira , C. C. Fonte , M. A. Pais , J. Fernandes

Data analysis of sunspot oscillation based on 6-hr SDO run of observation showed that low frequency (0.2 < ! < 1 mHz) oscillations are local similar to three and five minute oscillations. The oscillations in the sunspot are concentrated in…

Solar and Stellar Astrophysics · Physics 2018-09-19 Y. Zhugzhda , R. Sych

A sunspot acts as a waveguide in response to the dynamics of the solar interior; the trapped waves and oscillations could reveal its thermal and magnetic structures. We study the oscillations in a sunspot intruded by a light bridge, the…

Solar and Stellar Astrophysics · Physics 2016-10-19 Ding Yuan , Robert W. Walsh

The evolution of turbulent spots in a parallel shear flow is studied by means of full three-dimensional numerical simulations. The flow is bounded by free surfaces and driven by a volume force. Three regions in the spanwise spot…

Chaotic Dynamics · Physics 2009-11-07 Joerg Schumacher , Bruno Eckhardt

High cadence, multiwavelength, optical observations of solar magnetic bright points, captured at disk center using the ROSA and IBIS imaging systems on the Dunn Solar Telescope, are presented. Magnetic bright points manifesting in the Na I…

Solar and Stellar Astrophysics · Physics 2015-05-19 D. B. Jess , M. Mathioudakis , D. J. Christian , P. J. Crockett , F. P. Keenan

Surges often appear as a result of the emergence of magnetized plasma from the solar interior. Traditionally, they are observed in chromospheric lines such as H$\alpha$ 6563 \AA and Ca II 8542 \AA. However, whether there is a response to…

Solar and Stellar Astrophysics · Physics 2017-12-05 D. Nóbrega-Siverio , J. Martínez-Sykora , F. Moreno-Insertis , L. Rouppe van der Voort

We study the plasma flows in the solar photosphere during the emergence of two small active regions, NOAA 9021 and 10768. Using SOHO/MDI data, we find that the strong plasma upflows appear at the initial stage of active region formation,…

Solar and Stellar Astrophysics · Physics 2017-05-01 Anna Khlystova , Shin Toriumi

We measure the horizontal subsurface flow in a fast emerging active region (NOAA 11158) using the ring-diagram technique and the HMI high-spatial resolution Dopplergrams. This active region had a complex magnetic structure and displayed…

Solar and Stellar Astrophysics · Physics 2015-08-04 Kiran Jain , S. C. Tripathy , F. Hill

We investigate subsurface moat flow system around symmetrical sunspots of McIntosh type H and compare it to the flow system within supergranular cells. Representatives of both types of flows are constructed by means of statistical averaging…

Solar and Stellar Astrophysics · Physics 2015-06-19 M. Švanda , M. Sobotka , T. Bárta

We report the discovery of transient radio emission from the nearby optically-discovered TDE ASASSN-14li (distance of 90 Mpc), making it the first typical TDE detected in the radio, and unambiguously pointing to the formation of a…

High Energy Astrophysical Phenomena · Physics 2016-03-16 Kate D. Alexander , Edo Berger , James Guillochon , Bevin A. Zauderer , Peter K. G. Williams