ALMA as a prominence thermometer: First observations
| Autor: | Petr Heinzel, Arkadiusz Berlicki, Miroslav Bárta, Paweł Rudawy, Stanislav Gunár, Nicolas Labrosse, Krzysztof Radziszewski |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| ISSN: | 2041-8205 |
| Popis: | We present first prominence observations obtained with ALMA in Band 3 at the wavelength of 3 mm. High-resolution observations have been coaligned with the MSDP H$\alpha$ data from Wroclaw-Bialk\'{o}w large coronagraph at similar spatial resolution. We analyze one particular co-temporal snapshot, first calibrating both ALMA and MSDP data and then demonstrating a reasonable correlation between both. In particular we can see quite similar fine-structure patterns in both ALMA brightness temperature maps and MSDP maps of H$\alpha$ intensities. Using ALMA we intend to derive the prominence kinetic temperatures. However, having current observations only in one band, we use an independent diagnostic constraint which is the H$\alpha$ line integrated intensity. We develop an inversion code and show that it can provide realistic temperatures for brighter parts of the prominence where one gets a unique solution, while within faint structures such inversion is ill conditioned. In brighter parts ALMA serves as a prominence thermometer, provided that the optical thickness in Band 3 is large enough. In order to find a relation between brightness and kinetic temperatures for a given observed H$\alpha$ intensity, we constructed an extended grid of non-LTE prominence models covering a broad range of prominence parameters. We also show the effect of the plane-of-sky filling factor on our results. Comment: 9 pages, 3 figures, accepted for publication in the The Astrophysical Journal Letters |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|