Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ellerman bombs at high resolution. IV. Visibility in Na I and Mg I   Ellerman bombs are transient brightenings of the wings of the solar Balmer
lines that mark reconnection in the photosphere. Ellerman noted in 1917 that he
did not observe such brightenings in the Na I D and Mg I b lines. This
non-visibility should constrain EB interpretation, but has not been addressed
in published bomb modeling. We therefore test Ellerman's observation and
confirm it using high-quality imaging spectrometry with the Swedish 1-m Solar
Telescope. However, we find diffuse brightness in these lines that seems to
result from prior EBs. We tentatively suggest this is a post-bomb hot-cloud
phenomenon also found in recent EB spectroscopy in the ultraviolet.

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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: supr-con
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The categories of this paper are: cond-mat
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: physics
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The categories of this paper are: dg-ga