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.

9 pages, 3 figures, accepted for publication in ApJL

References in corpus (2)

• Observing the Sun with the Atacama Large Millimeter-submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping
• The solar chromosphere at millimetre and ultraviolet wavelengths. I. Radiation temperatures and a detailed comparison

Cited by in corpus (13)

• Observations of solar chromospheric oscillations at 3 mm with ALMA
• The Sun at millimeter wavelengths -- II. Small-scale dynamic events in ALMA Band 3
• 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 the variability of the quiet Sun at millimeter wavelengths
• Modeling the quiet Sun cell and network emission with ALMA
• 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
• Observations of pores and surrounding regions with CO 4.66 μm lines by BBSO/CYRA
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)
• The Solar ALMA Science Archive (SALSA)