90 research outputs found
ALMA as a prominence thermometer: First observations
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 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
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 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
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 Letter
Observations and Modeling of Line Asymmetries in Chromospheric Flares
International audienc
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