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相关论文: Centre to limb brightness variations from ALMA ful…

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We measured the center-to-limb variation of the brightness temperature, $T_b$, from ALMA full-disk images at two frequencies and inverted the solution of the transfer equation to obtain the electron temperature, $T_e$ as a function of…

太阳与恒星天体物理 · 物理学 2017-09-13 C. E. Alissandrakis , S. Patsourakos , A. Nindos , T. S. Bastian

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…

Measurements of the radius and limb brightening of the Sun provide important information about the solar atmosphere structure and temperature. The solar radius increases as the observation at radio frequency decreases, indicating that each…

太阳与恒星天体物理 · 物理学 2021-12-15 Fabian Menezes , Caius L. Selhorst , Carlos Guillermo Giménez de Castro , Adriana Valio

We present the first full-disk solar images obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 7 (0.86 mm; 347 GHz). In spite of the low spatial resolution (21"), several interesting results were obtained. During…

太阳与恒星天体物理 · 物理学 2022-05-25 C. E. Alissandrakis , T. S. Bastian , A. Nindos

Solar observations with the Atacama Large Millimeter/submillimeter Array (ALMA) provide us with direct measurements of the brightness temperature in the solar chromosphere. We study the temperature distributions obtained with ALMA Band 6…

太阳与恒星天体物理 · 物理学 2019-02-13 Shahin Jafarzadeh , Sven Wedemeyer , Mikolaj Szydlarski , Bart De Pontieu , Reza Rezaei , Mats Carlsson

ALMA observations of the Sun at mm-$\lambda$ offer a unique opportunity to investigate the temperature structure of the solar chromosphere. In this article we expand our previous work on modeling the chromospheric temperature of the quiet…

太阳与恒星天体物理 · 物理学 2020-08-19 C. E. Alissandrakis , A. Nindos , T. S. Bastian , S. Patsourakos

By direct measurements of the gas temperature, the Atacama Large Millimeter/sub-millimeter Array (ALMA) has yielded a new diagnostic tool to study the solar chromosphere. Here we present an overview of the brightness-temperature…

We report the results of the Atacama Large Millimeter/sub-millimeter Array (ALMA) observations of the solar chromosphere on the southern polar limb. Coordinated observations with the Interface Region Imaging Spectrograph (IRIS) are also…

太阳与恒星天体物理 · 物理学 2018-08-22 Takaaki Yokoyama , Masumi Shimojo , Takenori J. Okamoto , Haruhisa Iijima

The aim of this study is to demonstrate how the logarithmic millimeter continuum gradient observed using the Atacama Large Millimeter/submillimeter Array (ALMA) may be used to estimate optical thickness in the solar atmosphere. We discuss…

太阳与恒星天体物理 · 物理学 2019-05-01 Andrew S. Rodger , Nicolas Labrosse , Sven Wedemeyer , Mikolaj Szydlarski , Paulo J. A. Simões , Lyndsay Fletcher

We present an initial study of one of the first ALMA Band 3 observations of the Sun with the aim to characterise the diagnostic potential of brightness temperatures measured with ALMA on the Sun. The observation covers 48min at a cadence of…

We present the first high-resolution, simultaneous observations of the solar chromosphere in the optical and millimeter wavelength ranges, obtained with ALMA and the IBIS instrument at the Dunn Solar Telescope. In this paper we concentrate…

太阳与恒星天体物理 · 物理学 2019-08-27 Momchil E. Molnar , Kevin P. Reardon , Yi Chai , Dale Gary , Han Uitenbroek , Gianna Cauzzi , Steven R. Cranmer

Various solar features can be seen on maps of the Sun in the mm and sub-mm wavelength range. The recently installed Atacama Large Millimeter/submillimeter Array (ALMA) is capable of observing the Sun in that wavelength range with an…

太阳与恒星天体物理 · 物理学 2018-05-30 R. Brajša , D. Sudar , A. O. Benz , I. Skokić , M. Bárta , B. De Pontieu , S. Kim , A. Kobelski , M. Kuhar , M. Shimojo , S. Wedemeyer , S. White , P. Yagoubov , Y. Yan

The intensity of radiation at millimeter wavelengths from the solar atmosphere is closely related to the plasma temperature and the height of formation of the radiation is wavelength dependent. From that follows that the slope of the…

太阳与恒星天体物理 · 物理学 2023-01-18 Henrik Eklund , Mikolaj Szydlarski , Sven Wedemeyer

We present an overview of high resolution quiet Sun observations, from disk center to the limb, obtained with the Atacama Large mm and sub-mm Array (ALMA) at 3 mm. Seven quiet Sun regions were observed with resolution of up to 2.5" by 4.5".…

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…

天体物理学 · 物理学 2009-11-13 S. Wedemeyer-Boehm , H. -G. Ludwig , M. Steffen , J. Leenaarts , B. Freytag

We present first prominence observations obtained with ALMA in Band 3 at the wavelength of 3 mm. High-resolution observations have been coaligned with the MSDP H$\alpha$ data from Wroclaw-Bialk\'{o}w large coronagraph at similar spatial…

High-resolution observations of the solar chromosphere at millimeter wavelengths are now possible with the Atacama Large Millimeter Array (ALMA), promising to tackle many open problems in solar physics. Observations from other ground and…

太阳与恒星天体物理 · 物理学 2018-12-12 João M. da Silva Santos , Jaime de la Cruz Rodríguez , Jorrit Leenaarts

Aims. The main aim of the present analysis is to decipher (i) the small-scale bright features in solar images of the quiet Sun and active regions obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) and (ii) the ALMA…

太阳与恒星天体物理 · 物理学 2021-07-07 R. Brajsa , I. Skokic , D. Sudar , A. O. Benz , S. Krucker , H. -G. Ludwig , S. H. Saar , C. L. Selhorst

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…

太阳与恒星天体物理 · 物理学 2017-05-31 Kazumasa Iwai , Maria Loukitcheva , Masumi Shimojo , Sami K. Solanki , Stephen M. White

CONTEXT: The quiet Sun magnetic fields produce ubiquitous bright points (BPs) that cover a significant fraction of the solar surface. Their contribution to the total solar irradiance (TSI) is so-far unknown. AIMS: To measure the…

太阳与恒星天体物理 · 物理学 2015-06-03 J. A. Bonet , I. Cabello , J. Sanchez Almeida
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