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Related papers: Spectral Diagnostics of Solar Photospheric Bright …

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It has been suggested that the prompt emission in gamma-ray bursts (GRBs) could be described by radiation from the photosphere in a hot fireball. Such models must be tested by directly fitting them to data. In this work we use data from the…

High Energy Astrophysical Phenomena · Physics 2019-01-30 Björn Ahlgren , Josefin Larsson , Erik Ahlberg , Christoffer Lundman , Felix Ryde , Asaf Pe'er

We model the deepest observable layers of dark sunspot umbral atmospheres in terms of an empirical model which equally describes observed near infrared continuum intensities and line profiles. We use the umbral continuum intensity at 1.67…

Solar and Stellar Astrophysics · Physics 2012-10-17 Goetz Stellmacher , Eberhard Wiehr

Acoustic and magnetoacoustic waves are among the possible candidate mechanisms that heat the upper layers of solar atmosphere. A weak chromospheric plage near a large solar pore NOAA 11005 was observed on October 15, 2008 in the lines Fe I…

Solar and Stellar Astrophysics · Physics 2016-07-27 M. Sobotka , P. Heinzel , M. Švanda , J. Jurčák , D. del Moro , F. Berrilli

We investigate the dynamics of and the relations between small-scale penumbral and photospheric features near the outer penumbral boundary: penumbral grains (PGs), dark penumbral fibrils, granules, and photospheric G-band bright points. The…

Astrophysics · Physics 2009-11-10 J. A. Bonet , I. Marquez , R. Muller , M. Sobotka , A. Tritschler

The specification of the upper atmosphere strongly relies on solar proxies that can properly reproduce the solar energetic input in the UV. Whilst the microwave flux at 10.7 cm (also called F10.7 index) has been routinely used as a solar…

Solar and Stellar Astrophysics · Physics 2014-02-18 Thierry Dudok de Wit , Sean Bruinsma , Kiyoto Shibasaki

The solar atmosphere is filled with clusters of hot small-scale loops commonly known as Coronal Bright Points (CBPs). These ubiquitous structures stand out in the Sun by their strong X-ray and/or extreme-ultraviolet (EUV) emission for hours…

Solar and Stellar Astrophysics · Physics 2024-06-14 D. Nóbrega-Siverio , F. Moreno-Insertis , K Galsgaard , K. Krikova , L. Rouppe van der Voort , R. Joshi , M. S. Madjarska

Spectra of the cellular photospheric flows are determined from full-disk Doppler velocity observations acquired by the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO) spacecraft. Three different…

Solar and Stellar Astrophysics · Physics 2015-10-01 David H. Hathaway , Thibaud Teil , Aimee A. Norton , Irina Kitiashvili

Context. Magnetic Bright Points (MBPs) are small-scale magnetic features in the solar photosphere. They may be a possible source of coronal heating by rapid footpoint motions that cause magnetohydrodynamical waves. The number and size…

Solar and Stellar Astrophysics · Physics 2014-11-20 D. Utz , A. Hanslmeier , C. Möstl , R. Muller , A. Veronig , H. Muthsam

Some models of coronal heating suppose that convective motions at the photosphere shuffle the footpoints of coronal magnetic fields and thereby inject sufficient magnetic energy upward to account for observed coronal and chromospheric…

Solar and Stellar Astrophysics · Physics 2015-06-18 B. T. Welsch

We present an estimate of the polarized spectral index between the Planck 30 and 44 GHz surveys in $3.7^\circ$ pixels across the entire sky. We use an objective reference prior that maximises the impact of the data on the posterior and…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-13 Luke Jew , Richard Grumitt

We present new estimates of the brightness temperatures of Jupiter, Saturn, Uranus, and Neptune based on the measurements carried in 2009--2013 by PLANCK/LFI at 30, 44, and 70 GHz and released to the public in 2018. This work extends the…

In this paper we study 21-cm absorption spectra and the corresponding emission spectra toward bright continuum sources in the test region (326deg< l < 333 deg) of the Southern Galactic Plane Survey. This survey combines the high resolution…

Astrophysics · Physics 2009-11-07 John M. Dickey , N. M. McClure-Griffiths , B. M. Gaensler , A. J. Green

The Fermi Gamma-ray Space Telescope observed the bright and long GRB090902B, lying at a redshift of z = 1.822. Together the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) cover the spectral range from 8 keV to >300 GeV is…

$Context$. The thermal structure of the penumbra below its visible surface (i.e., $\tau_5 \ge 1$) has important implications for our present understanding of sunspots and their penumbrae: their brightness and energy transport, mode…

Solar and Stellar Astrophysics · Physics 2017-05-24 J. M. Borrero , M. Franz , R. Schlichenmaier , M. Collados , A. Asensio Ramos

We present model atmospheres for an Earth-like planet orbiting the entire grid of main sequence FGK stars with effective temperatures ranging from Teff = 4250K to Teff = 7000K in 250K intervals. We model the remotely detectable spectra of…

Earth and Planetary Astrophysics · Physics 2013-04-11 Sarah Rugheimer , Lisa Kaltenegger , Andras Zsom , Antígona Segura , Dimitar Sasselov

Aerosol particles experience significant photophoretic forces at low pressure. Previous work assumed the average particle temperature to be very close to the gas temperature. This might not always be the case. If the particle temperature or…

Statistical Mechanics · Physics 2016-09-09 C. Loesche , G. Wurm , T. Jankowski , M. Kuepper

We report the discovery of a brightness enhancement in the center of a large sunspot umbra at a wavelength of 3 mm using the Atacama Large Millimeter/sub-millimeter Array (ALMA). Sunspots are amongst the most prominent features on the solar…

Solar and Stellar Astrophysics · Physics 2017-05-31 Kazumasa Iwai , Maria Loukitcheva , Masumi Shimojo , Sami K. Solanki , Stephen M. White

In recent decades our understanding of solar active regions (ARs) has improved substantially due to observations made with better angular resolution and wider spectral coverage. While prior AR observations have shown that these structures…

Reported are UBV and uvbybeta observations of 15 candidates for Kepler primary astero- seismic targets and 14 other stars in the Kepler field, carried out at the M.G. Fracastoro station of the Catania Astrophysical Observatory. These data…

Solar and Stellar Astrophysics · Physics 2009-07-07 J. Molenda-Zakowicz , M. Jerzykiewicz , A. Frasca

Polar brightening of the Sun at radio frequencies has been studied for almost fifty years and yet a disagreement persists between solar atmospheric models and observations. Some observations reported brightening values much smaller than the…