Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bondi-Sachs metrics and Photon Rockets   We study the Bondi-Sachs rockets with nonzero cosmological constant. We
observe that the acceleration of the systems arises naturally in the asymptotic
symmetries of (anti-) de Sitter spacetimes. Assuming the validity of the
concepts of energy and mass previously introduced in asymptotically flat
spacetimes, we find that the emission of pure radiation energy balances the
loss of the Bondi mass in certain special families of the Bondi-Sachs rockets,
so in these there is no gravitational radiation.

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The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat