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We studied chromospheric oscillations using Atacama Large millimeter and sub-millimeter Array (ALMA) time-series of interferometric observations of the quiet Sun obtained at 3 mm with a 2-s cadence and a spatial resolution of a few arcsec.…

Solar and Stellar Astrophysics · Physics 2020-02-12 S. Patsourakos , C. E. Alissandrakis , A. Nindos , T. S. Bastian

The Ha line, one of the most studied chromospheric diagnostics, is a tracer for magnetic field structures, while its line core intensity provides an estimate of the mass density. The brightness temperatures from Atacama Large…

Solar and Stellar Astrophysics · Physics 2024-04-29 Sneha Pandit , Sven Wedemeyer , Mats Carlsson , Mikołaj Szydlarski

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…

Solar and Stellar Astrophysics · Physics 2020-08-19 C. E. Alissandrakis , A. Nindos , T. S. Bastian , S. Patsourakos

Aims. We use advanced 3D NLTE radiative magnetohydrodynamic simulations of the solar atmosphere to carry out detailed tests of chromospheric diagnostics at millimeter and submillimeter wavelengths. Methods. We focused on the diagnostics of…

Solar and Stellar Astrophysics · Physics 2015-02-18 Maria Loukitcheva , Sami Solanki , Mats Carlsson , Stephen White

The (sub)millimeter radiation of solar flares is poorly understood. Without spatial resolution, it cannot be compared easily to flare emissions in other wavelengths. The Atacama Large Millimeter-submillimeter Array (ALMA) offers sufficient…

Solar and Stellar Astrophysics · Physics 2023-02-01 I. Skokić , A. O. Benz , R. Brajša , D. Sudar , F. Matković , M. Bárta

The Atacama Large Millimeter/submillimeter Array (ALMA) allows for solar observations in the wavelength range of 0.3$-$10 mm, giving us a new view of the chromosphere. The measured brightness temperature at various frequencies can be fitted…

Solar and Stellar Astrophysics · Physics 2024-03-01 F. Matković , R. Brajša , M. Kuhar , A. O. Benz , H. -G. Ludwig , C. L. Selhorst , I. Skokić , D. Sudar , A. Hanslmeier

The Ca II H & K lines are strong chromospheric diagnostics that can be used to determine the temperature stratification and magnetic structure of the solar atmosphere. The Atacama Large Millimetre/Submillimetre Array (ALMA) offers…

Solar and Stellar Astrophysics · Physics 2024-05-09 Sneha Pandit , Sven Wedemeyer , Mats Carlsson

We present four daytime thermal images of Europa taken with the Atacama Large Millimeter Array. Together, these images comprise the first spatially resolved thermal dataset with complete coverage of Europa's surface. The resulting…

Earth and Planetary Astrophysics · Physics 2018-10-31 Samantha K. Trumbo , Michael E. Brown , Bryan J. Butler

Using ALMA observations, we performed the first systematic survey for transient brightenings (i.e. weak, small-scale episodes of energy release) in the quiet solar chromosphere at 3 mm. Our dataset included images of six 87'' x 87'' regions…

Solar and Stellar Astrophysics · Physics 2020-07-01 A. Nindos , C. E. Alissandrakis , S. Patsourakos , T. S. Bastian

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…

Solar and Stellar Astrophysics · Physics 2019-02-13 Shahin Jafarzadeh , Sven Wedemeyer , Mikolaj Szydlarski , Bart De Pontieu , Reza Rezaei , Mats Carlsson

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…

Solar and Stellar Astrophysics · Physics 2021-07-07 R. Brajsa , I. Skokic , D. Sudar , A. O. Benz , S. Krucker , H. -G. Ludwig , S. H. Saar , C. L. Selhorst

The Atacama Large Millimeter/submillimeter Array (ALMA) offers new diagnostic capabilities for studying the Sun, providing complementary insights through high spatial and temporal resolution at millimeter wavelengths. ALMA acts as a linear…

We present observations of a solar plage in the millimeter-continuum with the ALMA and in the Ca 8542 and Na 5896 spectral lines with the Interferometric BIdimensional Spectrometer (IBIS). Our goal is to compare the measurement of local gas…

Solar and Stellar Astrophysics · Physics 2022-07-27 Ryan Hofmann , Kevin Reardon , Ivan Milic , Momchil Molnar , Yi Chai , Han Uitenbroek

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…

Solar and Stellar Astrophysics · Physics 2022-05-25 C. E. Alissandrakis , T. S. Bastian , A. Nindos

The Cosmic Microwave Background (CMB) physics can be used to constrain the dark energy dynamics: B modes of the polarization of the diffuse CMB emission as well as the polarized signal towards clusters of galaxies are sensitive to the…

Astrophysics · Physics 2007-05-23 Paola Andreani , Carlo Baccigalupi

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

Using Atacama Large Millimeter/submillimeter Array (ALMA) observations of the quiet Sun at 1.26 and 3 mm, we study spatially resolved oscillations and transient brightenings, i.e. small, weak events of energy release. Both phenomena may…

Solar and Stellar Astrophysics · Physics 2021-08-18 A. Nindos , S. Patsourakos , C. E. Alissandrakis , T. S. Bastian

Observations of the Sun at millimeter and submillimeter wavelengths offer a unique probe into the structure, dynamics, and heating of the chromosphere; the structure of sunspots; the formation and eruption of prominences and filaments; and…

By observing bright and compact astronomical sources while also taking data with the 183 GHz Water Vapour Radiometers, ALMA will be able to measure the `empirical' relationship between fluctuations in the phase of the astronomical signal…

Instrumentation and Methods for Astrophysics · Physics 2009-07-28 Bojan Nikolic

Solar observations at sub-mm, mm and cm wavelengths offer a straightforward diagnostic of physical conditions in the solar atmosphere because they yield measurement of brightness temperature which, for optically thick features, equals…

Solar and Stellar Astrophysics · Physics 2022-09-07 Costas Alissandrakis , Timothy Bastian , Roman Brajša