Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Renewed activity from the X-ray transient SAXJ 1810.8-2609 with INTEGRAL   We report on the results of INTEGRAL observations of the neutron star low
mass X-ray binary SAX J1810.8-2609 during its latest active phase in August
2007. The current outburst is the first one since 1998 and the derived
luminosity is 1.1-2.6x10^36 erg s-1 in the 20-100 keV energy range. This low
outburst luminosity and the long-term time-average accretion rate of
~5x10^-12Msolar/yr suggest that SAXJ 1810.8-2609 is a faint soft X-ray
transient. During the flux increase, spectra are consistent with a thermal
Comptonization model with a temperature plasma of ~23-30 keV and an optical
depth of ~1.2-1.5, independent from luminosity of the system. This is a typical
low hard spectral state for which the X-ray emission is attributed to the
upscattering of soft seed photons by a hot, optically thin electron plasma.
During the decay, spectra have a different shape, the high energy tail being
compatible with a single power law. This confirm similar behavior observed by
BeppoSAX during the previous outburst, with absence of visible cutoff in the
hard X-ray spectrum. INTEGRAL/JEM-X instrument observed four X-ray bursts in
Fall 2007. The first one has the highest peak flux (~3.5Crab in 3--25 keV)
giving an upper limit to the distance of the source of about 5.7 kpc, for a
LEdd~3.8x10^38 erg s^-1. The observed recurrence time of ~1.2 days and the
ratio of the total energy emitted in the persistent flux to that emitted in the
bursts (~73) allow us to conclude that the burst fuel was composed by mixed
hydrogen and helium with X>0.4.

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The categories of this paper are: hep-lat
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: nlin
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga