Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Synchronous X-ray/Optical QPOs from the Black Hole LMXB MAXI J1820+070   We present high-speed optical photometry from SAAO and SALT on the black hole
LMXB \MAXI (ASSASN-18ey), some of it simultaneous with NICER, Swift and
Insight-HXMT X-ray coverage. We detect optical Quasi-Periodic Oscillations
(QPOs) that move to higher frequencies as the outburst progresses, tracking
both the frequency and evolution of similar X-ray QPOs previously reported.
Correlated X-ray/optical data reveal a complex pattern of lags, including an
anti-correlation and a sub-second lag that evolve over the first few weeks of
outburst. They also show correlated components separated by a lag equal to the
QPO period roughly centered on zero lag, implying that the inter-band
variability is strongly and consistently affected by these QPOs at a constant
phase lag of roughly +/- pi. The synchronisation of X-ray and optical QPOs
indicates that they must be produced in regions physically very close to each
other; we thus propose that they can be explained by a precessing jet model,
based on analogies with V404 Cyg and MAXI J1348-630.

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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn
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The categories of this paper are: cs
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: econ
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The categories of this paper are: chem-ph