Search results for "ULXs"

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Broadband X-ray spectral variability of the pulsing ULX NGC 1313 X-2

2021

[Context] It is thought that ultraluminous X-ray sources (ULXs) are mainly powered by super-Eddington accreting neutron stars or black holes as shown by the recent discovery of X-ray pulsations and relativistic winds. [Aims] This work presents a follow-up study of the spectral evolution over two decades of the pulsing ULX NGC 1313 X-2 in order to understand the structure of the accretion disc. The primary objective is to determine the shape and nature of the dominant spectral components by investigating their variability with the changes in the source luminosity. [Methods[ We performed a spectral analysis over the canonical 0.3-10.0 keV energy band of all the high signal-to-noise XMM-Newton…

AccretionULXsAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesContext (language use)Astrophysicsindividuals: NGC 1313 X-2 [X-rays]Astrophysics::Cosmology and Extragalactic AstrophysicsSpectral lineSettore FIS/05 - Astronomia E AstrofisicaX-rays: Individuals: NGC 1313 X-2ThermalCutoffAstrophysics::Solar and Stellar AstrophysicsBlack-body radiationX-rays: BinariesAstrophysics::Galaxy AstrophysicsPhysicsastro-ph.HEHigh Energy Astrophysical Phenomena (astro-ph.HE)Accretion (meteorology)Astronomy and AstrophysicsRadiusAccretion accretion disksNeutron starSpace and Planetary ScienceAccretion disksbinaries [X-rays]Astrophysics::Earth and Planetary AstrophysicsAstrophysics - High Energy Astrophysical PhenomenaX-rays: individuals:NGC 1313 X-2
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Long term X-ray spectral variability of the nucleus of M81

2003

We have analysed the soft X-ray emission from the nuclear source of the nearby spiral galaxy M81, using the available data collected with ROSAT, ASCA, BeppoSAX and Chandra. The source flux is highly variable, showing (sometimes dramatic: a factor of 4 in 20 days) variability at different timescales, from 2 days to 4 years, and in particular a steady increase of the flux by a factor of >~ 2 over 4 years, broken by rapid flares. After accounting for the extended component resolved by Chandra, the nuclear soft X-ray spectrum (from ROSAT/PSPC, BeppoSAX/LECS and Chandra data) cannot be fitted well with a single absorbed power-law model. Acceptable fits are obtained adding an extra component, …

PhysicsSolar massSpiral galaxyAstrophysics::High Energy Astrophysical PhenomenaAstrophysics (astro-ph)FluxFOS: Physical sciencesAstronomy and AstrophysicsAstrophysicsRadiusAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysicsBlack holeRotating black holeSpace and Planetary ScienceROSATX-ray x rays sources ULXsAbsorption (electromagnetic radiation)Astrophysics::Galaxy Astrophysics
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