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Bright points (BPs) are manifestations of small magnetic elements in the solar photosphere. Their brightness contrast not only gives insight into the thermal state of the photosphere (and chromosphere) in magnetic elements, but also plays…

The irradiance of the Sun is modulated on all time scales. Small-scale solar magnetic elements composed of quiet-Sun network and active region plages contribute to this modulation on solar cycle time scales. The evaluation of their contrast…

Solar and Stellar Astrophysics · Physics 2021-09-02 Fatima Kahil

We compare the rms contrast in observed speckle reconstructed G-band images with synthetic filtergrams computed from two magneto-hydrodynamic simulation snapshots. The observations consist of 103 bursts of 80 frames each taken at the Dunn…

Astrophysics · Physics 2009-11-13 Han Uitenbroek , Alexandra Tritschler , Thomas Rimmele

We investigate the relationship between the photospheric magnetic field of small-scale magnetic elements in the quiet Sun (QS) at disc centre, and the brightness at 214 nm, 300 nm, 313 nm, 388 nm, 397 nm, and at 525.02 nm. To this end we…

Solar and Stellar Astrophysics · Physics 2017-04-05 F. Kahil , T. L. Riethmüller , S. K. Solanki

Magnetic elements have an intensity contrast that depends on the type of region they are located in (e.g. quiet Sun, or active region plage). Observed values also depend on the spatial resolution of the data. Here we investigate the…

Solar and Stellar Astrophysics · Physics 2019-01-16 F. Kahil , T. L. Riethmüller , S. K. Solanki

We present accurate measurements of the central wavelengths of 4947 atomic absorption lines in the solar optical spectrum. The wavelengths, precise to a level ~ 50-150 m/s, are given for both flux and disc-centre spectra, as measured in…

Astrophysics · Physics 2009-10-30 Carlos Allende Prieto , Ramon J. Garcia Lopez

Long-term trends in the solar spectral irradiance are important to determine the impact on Earth's climate. These long-term changes are thought to be caused mainly by changes in the surface area covered by small-scale magnetic elements. The…

Solar and Stellar Astrophysics · Physics 2015-05-14 N. Afram , Y. C. Unruh , S. K. Solanki , M. Schuessler , S. K. Mathew

Our observations of the quiet Sun with the NST have yielded unanticipated results on smal-scale solar dynamic. Althought small-scale solar dynamic have been well-studied, the NST is enabling us to probe finer scale dynamic exploiting higher…

Solar and Stellar Astrophysics · Physics 2009-12-23 Aleksandra Andic

We present a dataset of high resolution spectra of the Sun and ten bright stars of the domains [6297-6303] and [6361-6367] Angtr{\"o}m. Solar spectra were obtained in the quiet Sun at various distances from disk centre with the ground based…

Instrumentation and Methods for Astrophysics · Physics 2025-03-11 Jean-Marie Malherbe

Changes in the solar surface area covered by small-scale magnetic elements are thought to cause long-term changes in the solar spectral irradiance, which are important for determining the impact on Earth's climate. To study the effect of…

Solar and Stellar Astrophysics · Physics 2015-05-20 N. Afram , Y. C. Unruh , S. K. Solanki , M. Schuessler , A. Lagg , A. Voegler

The last solar minimum has been unusually quiet compared to the previous minima (since space-based radiometric measurements are available). The Sun's magnetic flux was substantially lower during this minimum. Some studies also show that the…

Solar and Stellar Astrophysics · Physics 2015-09-02 F. Shakeri , L. Teriaca , S. K. Solanki

The continuum intensity at wavelengths around 1 mm provides an excellent way to probe the solar chromosphere. Future high-resolution millimetre arrays, such as the Atacama Large Millimeter Array (ALMA), will thus produce valuable input for…

Astrophysics · Physics 2009-11-13 S. Wedemeyer-Boehm , H. -G. Ludwig , M. Steffen , J. Leenaarts , B. Freytag

The Sunrise balloon-borne solar observatory consists of a 1m aperture Gregory telescope, a UV filter imager, an imaging vector polarimeter, an image stabilization system and further infrastructure. The first science flight of Sunrise…

The determination of the cutoff frequency in real solar observations under different local physical conditions is an important and insufficiently explored aspect of waves in solar physics. This work utilizes the near ultraviolet (NUV)…

Solar and Stellar Astrophysics · Physics 2026-05-14 Pradeep Kayshap , Gayathri Hegde , Z. E. Musielak , Kris Murawski , Tobıas Felipe

On 12 March 1996 we obtained observations of the quiet Sun with the SUMER instrument. The observa- tions were sequences of 15-20 second exposures of ultraviolet emission line profiles and of the neighboring continua. These data contain…

Astrophysics · Physics 2009-10-30 Mats Carlsson , Philip G. Judge , Klaus Wilhelm

We present a visual determination of the number of bright points (BPs) existing in the quiet Sun, which are structures though to trace intense kG magnetic concentrations. The measurement is based on a 0.1 arcsec angular resolution G-band…

Solar and Stellar Astrophysics · Physics 2015-03-16 J. Sanchez Almeida , J. A. Bonet , B. Viticchie , D. Del Moro

The contrasts of features in the quiet Sun are studied using filtergrams recorded by the Broad-band Filter Imager on the Hinode/Solar Optical Telescope. In a first step, the scattered light originating in the instrument is modeled using…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. K. Mathew , V. Zakharov , S. K. Solanki

Aims: The aim of this paper is to demonstrate that millimeter wave data can be used to distinguish between various atmospheric models of sunspots, whose temperature structure in the upper photosphere and chromosphere has been the source of…

Solar and Stellar Astrophysics · Physics 2015-01-14 Maria A. Loukitcheva , Sami K. Solanki , Stephen M. White

The brightness temperature of the radio free-free emission at millimeter range is an effective tool for characterizing the vertical structure of the solar chromosphere. In this paper, we report on the first single-dish observation of a…

Solar and Stellar Astrophysics · Physics 2015-06-24 Kazumasa Iwai , Masumi Shimojo

The third science flight of the balloon-borne solar observatory Sunrise carries three entirely new post-focus science instruments with spectropolarimetric capabilities, concurrently covering an extended spectral range from the near…

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