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TOPIC: Atacama Large Millimeter Array
Blobrana


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ALMA
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Title: Observing the Sun with the Atacama Large Millimeter-submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping
Author: S.M. White, K. Iwai, N.M.Phillips, R.E. Hills, A. Hirota, P. Yagoubov, G. Siringo, M. Shimojo, T.S. Bastian, A.S. Hales, T. Sawada, S. Asayama, M. Sugimoto, R.G. Marson, W. Kawasaki, E. Muller, T. Nakazato, K. Sugimoto, R. Brajsa, I. Skokic, M. Barta, S. Kim, A. Remijan, I. de Gregorio, S.A. Corder, H.S. Hudson, M. Loukitcheva, B. Chen, B. De Pontieu, G.D. Fleishmann, D.E. Gary, A. Kobelski, S. Wedemeyer, Y. Yan

The Atacama Large Millimeter-submillimeter Array (ALMA) radio telescope has commenced science observations of the Sun starting in late 2016. Since the Sun is much larger than the field of view of individual ALMA dishes, the ALMA interferometer is unable to measure the background level of solar emission when observing the solar disk. The absolute temperature scale is a critical measurement for much of ALMA solar science, including the understanding of energy transfer through the solar atmosphere, the properties of prominences, and the study of shock heating in the chromosphere. In order to provide an absolute temperature scale, ALMA solar observing will take advantage of the remarkable fast-scanning capabilities of the ALMA 12m dishes to make single-dish maps of the full Sun. This article reports on the results of an extensive commissioning effort to optimize the mapping procedure, and it describes the nature of the resulting data. Amplitude calibration is discussed in detail: a path that utilizes the two loads in the ALMA calibration system as well as sky measurements is described and applied to commissioning data. Inspection of a large number of single-dish datasets shows significant variation in the resulting temperatures, and based on the temperature distributions we derive quiet-Sun values at disk center of 7300 K at lambda=3 mm and 5900 K at lambda=1.3 mm. These values have statistical uncertainties of order 100 K, but systematic uncertainties in the temperature scale that may be significantly larger. Example images are presented from two periods with very different levels of solar activity. At a resolution of order 25 arcsec, the 1.3 mm wavelength images show temperatures on the disk that vary over about a 2000 K range.

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ALMA Starts Observing the Sun

New images taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile have revealed otherwise invisible details of our Sun, including a new view of the dark, contorted centre of a sunspot that is nearly twice the diameter of the Earth. The images are the first ever made of the Sun with a facility where ESO is a partner. The results are an important expansion of the range of observations that can be used to probe the physics of our nearest star. The ALMA antennas had been carefully designed so they could image the Sun without being damaged by the intense heat of the focussed light.
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Atacama Large Millimeter/submillimeter Array
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First Light for Band 5 at ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA) in Chile has begun observing in a new range of the electromagnetic spectrum. This has been made possible thanks to new receivers installed at the telescope's antennas, which can detect radio waves with wavelengths from 1.4 to 1.8 millimetres - a range previously untapped by ALMA. This upgrade allows astronomers to detect faint signals of water in the nearby Universe.
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New Webcam for ALMA Offers Stunning Views of the Array

A new high-definition camera has been installed at the Atacama Large Millimeter/submillimeter Array (ALMA), providing a 24/7 interactive view of the telescope's mountain home at 16,500 feet above sea level.
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Sharpest View Ever of Star Formation in the Distant Universe

ALMA's Long Baseline Campaign has produced a spectacular image of a distant galaxy being gravitationally lensed. The image shows a magnified view of the galaxy's star-forming regions, the likes of which have never been seen before at this level of detail in a galaxy so remote. The new observations are far sharper than those made using the NASA/ESA Hubble Space Telescope, and reveal star-forming clumps in the galaxy equivalent to giant versions of the Orion Nebula in the Milky Way.
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Title: Solar ALMA Observations - A new view of our host star
Author: Sven Wedemeyer, Tim Bastian, Roman Brajsa, Miroslav Barta, Masumi Shimojo, Antonio Hales, Pavel Yagoubov, Hugh Hudson

ALMA provides the necessary spatial, temporal and spectral resolution to explore central questions in contemporary solar physics with potentially far-reaching implications for stellar atmospheres and plasma physics. It can uniquely constraint the thermal and magnetic field structure in the solar chromosphere with measurements that are highly complementary to simultaneous observations with other ground-based and space-borne instruments. Here, we highlight selected science cases.

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Final Antenna Delivered to ALMA
All 66 ALMA antennas now handed over to the observatory

The final antenna for the Atacama Large Millimetre/submillimetre Array (ALMA) project has just been handed over to the ALMA Observatory. The 12-metre-diameter dish was manufactured by the European AEM Consortium and also marks the successful delivery of a total of 25 European antennas - the largest ESO contract so far.
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ALMA resumes operations after end of workers' strike

The Atacama Large Millimeter/submillimeter Array (ALMA) is pleased to announce that the process to restore full operational conditions will start on Monday September 9th, after 17-day strike declared by the local labor union workers.
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Workers at the Alma telescope in Chile go on strike

Workers at the world's biggest radio telescope in Chile have gone on strike to demand a pay rise.
They are also demanding benefits to compensate for the high altitude and isolation they endure.



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New telescope brings distant galaxies into sharp focus

Durham University astronomers have played a key role in research using a powerful new telescope to bring images of the distant Universe into much sharper focus.
Fertile star-forming galaxies that were highly active when the Universe was at a relatively youthful age - less than three billion years old - can now be seen in images that are significantly sharper than anything previously possible. 
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