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Context. The radiative losses in the solar chromosphere vary from 4~kW~m$^{-2}$ in the quiet Sun, to 20~kW~m$^{-2}$ in active regions. The mechanisms that transport non-thermal energy to and deposit it in the chromosphere are still not…

Solar and Stellar Astrophysics · Physics 2018-04-18 Jorrit Leenaarts , Jaime de la Cruz Rodríguez , Sanja Danilovic , Göran Scharmer , Mats Carlsson

We analyse the multi-frequency radio spectral properties of $41$ 6GHz-detected ALMA-identified, submillimetre galaxies (SMGs), observed at 610MHz, 1.4GHz, 6GHz with GMRT and the VLA. Combining high-resolution ($\sim0.5''$) 6GHz radio and…

The Simons Observatory is a ground-based telescope array located at an elevation of 5200 meters, in the Atacama Desert in Chile, designed to measure the temperature and polarization of the cosmic microwave background. It comprises four…

We report the identification of a very metal-poor damped Lyman-alpha system (DLA) at z_abs = 3.067295 that is modestly carbon-enhanced, with an iron abundance of ~1/700 solar ([Fe/H] = -2.84) and [C,O/Fe] ~ +0.6. Such an abundance pattern…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Ryan Cooke , Max Pettini , Michael Murphy

Hydrogen recombination lines (HRLs) are valuable diagnostics of the physical conditions in ionized regions around high-mass stars. Understanding their broadening mechanisms and intensity trends can provide insights into the densities,…

We have analyzed the NH$_{2}$CHO, HNCO, H$_{2}$CO, and CH$_{3}$CN ($^{13}$CH$_{3}$CN) molecular lines at an angular resolution of $\sim 0.3''$ obtained by the Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 toward 30 high-mass…

Observations of the emission at radio, millimeter, sub-millimeter, and infrared wavelengths in the center of the solar disk validate the auto-consistence of semi-empirical models of the chromosphere. Theoretically, these models must…

Solar and Stellar Astrophysics · Physics 2016-07-20 Victor De la Luz

We introduce an ALMA band 3 spectroscopic survey, targeting the brightest submillimeter galaxies (SMGs) in the COSMOS field. Here we present the first results based on the 18 primary SMGs that have 870 $\mu$m flux densities of…

We analyze observations from the Interface Region Imaging Spectrograph of the Mg II k line, the Mg II UV subordinate lines, and the O I 135.6 nm line to better understand the solar plage chromosphere. We also make comparisons with…

Solar and Stellar Astrophysics · Physics 2015-08-21 Mats Carlsson , Jorrit Leenaarts , Bart De Pontieu

We present a study of the radio properties of 870$\mu$m-selected submillimetre galaxies (SMGs), observed at high resolution with ALMA in the Extended Chandra Deep Field South. From our initial sample of 76 ALMA SMGs, we detect 52 SMGs at…

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 Atacama Large Millimeter-Submillimeter Array (ALMA) has opened a new window for studying the Sun via high-resolution high-sensitivity imaging at millimeter wavelengths. In this contribution I review the capabilities of the instrument…

Solar and Stellar Astrophysics · Physics 2019-02-13 Maria Loukitcheva

Solar observations from millimeter to ultraviolet wavelengths show that there is a temperature minimum between photosphere and chromosphere. Analysis based on semi-empirical models locate this point at about 500 km over the photosphere. The…

Solar and Stellar Astrophysics · Physics 2015-06-18 Victor De la Luz , Miguel Chavez , Emanuele Bertone , Guillermo Gimenez de Castro

We present a combined, homogenized analysis of archival Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA) observations of the spatially resolved 340 GHz (870 $\mu$m) continuum emission from 105 nearby…

Earth and Planetary Astrophysics · Physics 2018-10-17 Sean M. Andrews , Marie Terrell , Anjali Tripathi , Megan Ansdell , Jonathan P. Williams , David J. Wilner

This study investigates and compares brightness and area of coronal bright points (CBPs) inside and outside of coronal holes (CHs) using the single-dish Band 6 observations by the Atacama Large Millimeter/submillimeter Array (ALMA),…

Solar and Stellar Astrophysics · Physics 2023-02-22 F. Matković , R. Brajša , M. Temmer , S. G. Heinemann , H. -G. Ludwig , S. H. Saar , C. L. Selhorst , I. Skokić , D. Sudar

The variability of H$\alpha$ chromospheric activity of solar-like stars is investigated by using the time-domain data of LAMOST Medium-Resolution Spectroscopic Survey (MRS). We use $R_\mathrm{H\alpha}$ index (ratio of H$\alpha$ luminosity…

Solar and Stellar Astrophysics · Physics 2025-12-10 Han He , Ali Luo , Haotong Zhang , Song Wang

We present Atacama Large Millimeter/submillimeter Array observations of 99.02 GHz free-free and H40$\alpha$ emission from the centre of the nearby starburst galaxy NGC 253. We calculate electron temperatures of 3700-4500 K for the…

Astrophysics of Galaxies · Physics 2015-05-20 G. J. Bendo , R. J. Beswick , M. J. D'Cruze , C. Dickinson , G. A. Fuller , T. W. B. Muxlow

The distribution of stellar $\mathrm{H}\alpha$ chromospheric activity with respect to stellar atmospheric parameters (effective temperature $T_\mathrm{eff}$, surface gravity $\log\,g$, and metallicity $\mathrm{[Fe/H]}$) and…

Solar and Stellar Astrophysics · Physics 2023-08-01 Han He , Weitao Zhang , Haotong Zhang , Song Wang , Ali Luo , Jun Zhang

We aimed to measure the CMF in the evolved W33-Main star-forming protocluster to compare it with CMF recently obtained in other Galactic star-forming regions, including the ones included in the ALMA-IMF program. We used observations from…

Observations of chromospheric spectral lines near and beyond the solar limb provide information on the solar chromosphere without any photospheric contamination. For ground-based observations near and off the limb with real-time image…

Solar and Stellar Astrophysics · Physics 2012-03-12 C. Beck , R. Rezaei