Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A deep XMM-Newton observation of the ultraluminous X-ray source HoII X-1
  : the case against a 1000 solar mass black hole   We present results from a 112 ks long look by XMM-Newton at the ultraluminous
X-ray source (ULX) Holmberg II X-1, long thought to be the one of best
candidates for the missing class of intermediate mass black holes (IMBHs). Our
data comprises the first high quality XMM-Newton/RGS spectrum of an ULX, and an
XMM-Newton/EPIC spectrum with unprecedented signal-to-noise. A detailed timing
analysis shows that any variability on time-scales of minutes to hours is very
weak (< few per cent fractional rms), though larger amplitude variations on
much shorter time-scales could be hidden by photon counting statistics. This
result suggests that if Ho II X-1 harbours an IMBH, then we are observing this
source in a highly unusual and atypical state when compared with the known
variability behaviour of other accreting systems of large mass. Moreover unlike
Galactic X-ray binaries, our spectral analysis indicates the possible presence
of an optically-thick low temperature corona. Taken together our timing and
spectral analysis suggests that the compact companion is most-likely a high
luminosity analogue of black hole binary systems similar to GRS 1915+105, the
Galactic microquasar, harbouring a compact object of mass no greater than 100
solar masses.

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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: q-alg
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con