Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Keck/OSIRIS Pa$\beta$ high-contrast imaging and updated constraints on
  PDS~70b   We present a high-contrast imaging search for Pa$\beta$ line emission from
protoplanets in the PDS~70 system with Keck/OSIRIS integral field spectroscopy.
We applied the high-resolution spectral differential imaging technique to the
OSIRIS $J$-band data but did not detect the Pa$\beta$ line at the level
predicted using the parameters of \cite{Hashimoto2020}. This lack of Pa$\beta$
emission suggests the MUSE-based study may have overestimated the line width of
H$\alpha$. We compared our Pa$\beta$ detection limits with the previous
H$\alpha$ flux and H$\beta$ limits and estimated $A_{\rm V}$ to be $\sim0.9$
and 2.0 for PDS~70~b and c respectively. In particular, PDS~70~b's $A_{\rm V}$
is much smaller than implied by high-contrast near-infrared studies, which
suggests the infrared-continuum photosphere and the hydrogen-emitting regions
exist at different heights above the forming planet.

21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
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The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga