Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low Levels of Sulphur Dioxide Contamination of Phosphine Spectra from
  Venus' Atmosphere   New analysis is presented of the 1.1 mm wavelength absorption lines in Venus'
atmosphere that suggested the presence of phosphine. We confirm that ALMA
detected absorption at the PH3 1-0 wavelength in 2019, from an optimised
spectrum covering half of the planetary disc. Sulphur dioxide
line-contamination was then <10%, from modelling of a simultaneous ALMA
spectrum of SO2. We retrieve an SO2 observation from the JCMT archive that was
simultaneous within a few days of the PH3 1-0 spectrum obtained in June 2017,
and demonstrate that contamination was also <10%. The contamination-subtracted
ALMA and JCMT spectra (of 6-7 sigma confidence) are now consistent with similar
levels of absorption. The variation is ~25% around -1.5 10-4 of the continuum,
albeit not for identical planetary areas. This similarity suggests the
abundance that can be attributed to phosphine in Venus' atmosphere was broadly
similar in 2017 and 2019.

29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex