English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The Atacama Large Millimeter-submillimeter Array (ALMA) radio telescope hascommenced science observations of the Sun starting in late 2016. Since the Sunis much larger than the field of view of individual ALMA dishes, the ALMAinterferometer is unable to measure the background level of solar emission whenobserving the solar disk. The absolute temperature scale is a criticalmeasurement for much of ALMA solar science, including the understanding ofenergy transfer through the solar atmosphere, the properties of prominences,and the study of shock heating in the chromosphere. In order to provide anabsolute temperature scale, ALMA solar observing will take advantage of theremarkable fast-scanning capabilities of the ALMA 12m dishes to makesingle-dish maps of the full Sun. This article reports on the results of anextensive commissioning effort to optimize the mapping procedure, and itdescribes the nature of the resulting data. Amplitude calibration is discussedin detail: a path that utilizes the two loads in the ALMA calibration system aswell as sky measurements is described and applied to commissioning data.Inspection of a large number of single-dish datasets shows significantvariation in the resulting temperatures, and based on the temperaturedistributions we derive quiet-Sun values at disk center of 7300 K at lambda=3mm and 5900 K at lambda=1.3 mm. These values have statistical uncertainties oforder 100 K, but systematic uncertainties in the temperature scale that may besignificantly larger. Example images are presented from two periods with verydifferent levels of solar activity. At a resolution of order 25 arcsec, the 1.3mm wavelength images show temperatures on the disk that vary over about a 2000K range.

Observing the Sun with the Atacama Large Millimeter-submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping