ALMA detection of dark chromospheric holes in the quiet Sun

Abstract

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 observations in the UV and visible as well as with photospheric magnetograms. ALMA images clearly reveal the presence of distinct particularly dark/cool areas in the millimeter maps having temperatures as low as 60% of the normal quiet Sun at 3 mm, which are not seen in the other data. We speculate that ALMA is sensing cool chromospheric gas, whose presence had earlier been inferred from infrared CO spectra.

arXiv comment9 pages, 3 figures, accepted for publication in ApJL

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Cited by in corpus (16)

• The Sun at millimeter wavelengths I. Introduction to ALMA Band 3 observations
• Observations of solar chromospheric oscillations at 3 mm with ALMA
• The Sun at millimeter wavelengths -- II. Small-scale dynamic events in ALMA Band 3
• The Formation Height of Millimeter-wavelength Emission in the Solar Chromosphere
• Transient brightenings in the quiet Sun detected by ALMA at 3 mm
• High-frequency wave power observed in the solar chromosphere with IBIS and ALMA
• An overall view of temperature oscillations in the solar chromosphere with ALMA
• ALMA observations of transient heating in a solar active region
• Modeling the quiet Sun cell and network emission with ALMA
• ALMA observations of the variability of the quiet Sun at millimeter wavelengths
• A first look at the submillimeter Sun with ALMA
• High-frequency oscillations in small chromospheric bright features observed with ALMA
• Flares detected in ALMA single-dish images of the Sun
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)
• Observations of pores and surrounding regions with CO 4.66 μm lines by BBSO/CYRA
• The Solar ALMA Science Archive (SALSA)