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The precise mechanisms that provide the non-radiative energy for heating the chromosphere and the corona of the Sun and other stars are at the focus of intense contemporary research. Observations at submm/mm wavelengths are particularly…

Solar and Stellar Astrophysics · Physics 2016-10-19 R. Liseau , V. De la Luz , E. O'Gorman , E. Bertone , M. Chavez , F. Tapia

The precise mechanisms that provide the non-radiative energy for heating the chromosphere and the corona of the Sun and those of other stars constitute an active field of research. By studying stellar chromospheres one aims at identifying…

We recently announced the detection of an unknown submillimeter source in our ALMA observations of alpha Cen AB. The source was detected in two epochs, a strong detection at 445~GHz and one at lower significance at 343.5~GHz. After valuable…

Solar and Stellar Astrophysics · Physics 2015-12-18 R. Liseau , W. Vlemmings , E. O'Gorman , E. Bertone , M. Chavez , V. De la Luz

At radio wavelengths, solar-type stars emit thermal free-free and gyroresonance, gyrosynchrotron, and impulsive coherent emission. Thermal free-free emission originates at layers where the optical depth is close to unit, while high…

Solar and Stellar Astrophysics · Physics 2018-08-29 C. Trigilio , G. Umana , F. Cavallaro , C. Agliozzo , P. Leto , C. S. Buemi , A. Ingallinera , F. Bufano , S. Riggi

The thermal radio and sub-mm emission from the winds of massive stars is investigated and the contribution to the emission due to the stellar wind acceleration region and clumping of the wind is quantified. Building upon established theory,…

Solar and Stellar Astrophysics · Physics 2016-09-07 S. Daley-Yates , I. R. Stevens , T. D. Crossland

The unprecedented sensitivity of the Atacama Large millimeter/submillimeter array (ALMA) is providing many new discoveries. Several of these are serendipitous to the original goal of the observations. We report the discovery of previously…

Solar and Stellar Astrophysics · Physics 2016-01-21 W. Vlemmings , S. Ramstedt , M. Maercker , B. Davidsson

Chromospheres and coronae are common phenomena on solar-type stars. Understanding the energy transfer to these heated atmospheric layers requires direct access to the relevant empirical data. Study of these structures has, by and large,…

The alpha Centauri binary system, owing to its duplicity, proximity and brightness, and its components' likeness to the Sun, is a fundamental calibrating object for the theory of stellar structure and evolution and the determination of…

Astrophysics · Physics 2009-11-13 G. F. Porto de Mello , W. Lyra , G. R. Keller

The infrared spectral energy distributions (SEDs) of main-sequence galaxies in the early universe (z > 4) is currently unconstrained as infrared continuum observations are time consuming and not feasible for large samples. We present…

Sub-millimeter observations reveal the star-formation activity obscured by dust in the young Universe. It still remains unclear how galaxies detected at sub-millimeter wavelengths are related to ultraviolet/optical-selected galaxies in…

Astrophysics of Galaxies · Physics 2023-09-07 Tomoko L. Suzuki , Sophie E. van Mierlo , Karina I. Caputi

The Atacama Large Millimeter/submillimeter Array (ALMA) is a new powerful tool for observing the Sun at high spatial, temporal, and spectral resolution. These capabilities can address a broad range of fundamental scientific questions in…

We use the Atacama Large sub/Millimetre Array (ALMA) to efficiently observe spectral lines across Bands 3, 4, 5, 6, 7, and 8 at high-resolution (0.5" - 0.1") for 16 bright southern Herschel sources at $1.5 < z < 4.2$. With only six and a…

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of a quiet-Sun region at a wavelength of 3 mm, obtained during the first solar ALMA cycle on April 27, 2017, and compare them with available chromospheric…

Solar and Stellar Astrophysics · Physics 2019-06-05 Maria A. Loukitcheva , Stephen M. White , Sami K. Solanki

We performed a millimetric survey of a sample of 24 post-AGB stars aimed to search for emission from circumstellar matter, in order to investigate the physical properties of the outer parts of the envelopes. The observations were conducted…

Astrophysics · Physics 2009-11-11 C. S. Buemi , G. Umana , C. Trigilio , P. Leto

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

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…

We present 1.3 mm observations of the Sun-like star $\tau$ Ceti with the Atacama Large Millimeter/submillimeter Array (ALMA) that probe angular scales of $\sim1$'' (4 AU). This first interferometric image of the $\tau$ Ceti system, which…

We have carried out high resolution observations with Atacama Large Millimeter/Submillimeter Array (ALMA) of continuum emission from Orion KL region. We identify 11 compact sources at ALMA band 6 (245 GHz) and band 7 (339 GHz), including…

Solar and Stellar Astrophysics · Physics 2015-06-23 Tomoya Hirota , Mi Kyoung Kim , Yasutaka Kurono , Mareki Honma

Pulsars are neutron stars, stellar corpses left over after supernova explosions of stars about ten times as massive as our Sun, with densities comparable to the atomic nucleus', spinning with periods from few milliseconds up to few seconds,…

Proxima Centauri (Cen) has been the subject of many flaring studies due to its proximity and potential to host habitable planets. The discovery of millimeter flares from this M dwarf with ALMA has opened a new window into the flaring…

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