Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC 7793 P13

Israel, G. L.; Papitto, A.; Esposito, P.; Stella, L.; Zampieri, L.; Belfiore, A.; Castillo, G. A. Rodríguez; Luca, A. De; Tiengo, A.; Haberl, F.; Greiner, J.; Salvaterra, R.; Sandrelli, S.; Lisini, Gianni

doi:10.1093/mnrasl/slw218

Cited by 315 publications

(187 citation statements)

References 21 publications

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“…The broadband spectra observed are generally consistent with the expectation for super-Eddington accretion onto a compact stellar remnant (e.g., Shakura & Sunyaev 1973;Dotan & Shaviv 2011). Indeed, we now know that at least three of this population of extreme ULXs are actually highly super-Eddington neutron stars Fürst et al 2016;Israel et al 2017aIsrael et al , 2017b. Furthermore, in the case of NGC 1313 X-1, anotherL 10 X 40 erg s −1 ULX, discrete absorption features from a massive outflow have now finally been detected Walton et al 2016b), following an initial suggestion that low-energy (∼1 keV) residuals could be related to such a wind (Middleton et al 2014.…”

Section: Introductionsupporting

confidence: 80%

The Broadband Spectral Variability of Holmberg IX X-1

Walton

Fürst

Harrison

et al. 2017

ApJ

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We present results from four new broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 ( > L 10 X 40 erg s −1 ), performed by Suzaku and NuSTAR in coordination. Combined with the archival data, we now have broadband observations of this remarkable source from six separate epochs. Two of these new observations probe lower fluxes than seen previously, allowing us to extend our knowledge of the broadband spectral variability exhibited. The spectra are well fit by two thermal blackbody components thatdominate the emission below 10 keV, as well as a steep (G~3.5) power-law tail thatdominates above ∼15 keV. Remarkably, while the 0.3-10.0 keV flux varies by a factor of ∼3 between all these epochs, the 15-40 keV flux varies by only ∼20%. Although the spectral variability is strongest in the ∼1-10 keV band, both of the thermal components are required to vary when all epochs are considered. We also revisit the search for iron absorption features byleveraging the high-energy NuSTAR data to improve our sensitivity to extreme velocity outflows in light of the ultra-fast outflow recently detected in NGC 1313 X-1. Iron absorption from a similar outflow along our line of sight can be ruled out in this case. We discuss these results in the context of superEddington accretion models that invoke a funnel-like geometry for the inner flow, and propose a scenario in which we have an almost face-on view of a funnel that expands to larger radii with increasing flux, resulting in an increasing degree of geometrical collimation for the emission from intermediate-temperature regions.

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Section: Introductionsupporting

confidence: 80%

The Broadband Spectral Variability of Holmberg IX X-1

Walton

Fürst

Harrison

et al. 2017

ApJ

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“…The recent discovery that a number of ultra-luminous X-ray sources (ULXs: M82 X-2, NGC 7793 P13 and NGC 5907) are pulsating NSs (Bachetti et al 2014;Israel et al 2017b;Fürst et al 2016;Israel et al 2017a) has lead to the suggestion that ULXs might be HMXBs (Ekşi et al 2015;Kluźniak & Lasota 2015;Shao & Li 2015;Mushtukov et al 2015), including BeHMXBs (Karino & Miller 2016;Christodoulou et al 2017), and which could therefore suggest that some ULXs might potentially lead to the production DNS systems.…”

Section: Ulxs: Origin and Connection To Dns Progenitors?mentioning

confidence: 99%

Formation of Double Neutron Star Systems

Tauris

Krämer

Freire

et al. 2017

ApJ

642

690

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Double neutron star (DNS) systems represent extreme physical objects and the endpoint of an exotic journey of stellar evolution and binary interactions. Large numbers of DNS systems and their mergers are anticipated to be discovered using the Square-Kilometre-Array searching for radio pulsars and high-frequency gravitational wave detectors (LIGO/VIRGO), respectively. Here we discuss all key properties of DNS systems, as well as selection effects, and combine the latest observational data with new theoretical progress on various physical processes with the aim of advancing our knowledge on their formation. We examine key interactions of their progenitor systems and evaluate their accretion history during the high-mass X-ray binary stage, the common envelope phase and the subsequent Case BB mass transfer, and argue that the first-formed NSs have accreted at most ∼ 0.02 M ⊙ . We investigate DNS masses, spins and velocities, and in particular correlations between spin period, orbital period and eccentricity. Numerous Monte Carlo simulations of the second supernova (SN) events are performed to extrapolate pre-SN stellar properties and probe the explosions. All known close-orbit DNS systems are consistent with ultra-stripped exploding stars. Although their resulting NS kicks are often small, we demonstrate a large spread in kick magnitudes which may, in general, depend on the past interaction history of the exploding star and thus correlate with the NS mass. We analyze and discuss NS kick directions based on our SN simulations. Finally, we discuss the terminal evolution of close-orbit DNS systems until they merge and possibly produce a short γ-ray burst.

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“…Systematically higher Eddington ratios, slightly above unity, have been reported for SMBHs in quasars at very high redshifts (z ∼ 6 and above; Fan et al 2006, Willott et al 2010, De Rosa et al 2011, while in the local universe, ultraluminous X-ray sources (ULXs) are believed to often be hosted by stellar mass compact objects accreting significantly above the Eddington limit. Notably, X-ray pulsations have been detected for three ULXs, implying the compact object in those systems are neutron stars (Bachetti et al 2014, Fürst et al 2016, Israel et al 2017a, with an inferred peak isotropic luminosity of ∼ 1000 times the Eddington limit in at least one system (Israel et al 2017b). Despite its importance, the observed Eddington limited accretion in z = 6 − 7 quasars remains poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Eddington-limited Accretion in z ∼ 2 WISE-selected Hot, Dust-obscured Galaxies

Jun

Assef

et al. 2018

ApJ

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Hot, Dust-Obscured Galaxies, or "Hot DOGs", are a rare, dusty, hyperluminous galaxy population discovered by the WISE mission. Predominantly at redshifts 2-3, they include the most luminous known galaxies in the universe. Their high luminosities likely come from accretion onto highly obscured super massive black holes (SMBHs). We have conducted a pilot survey to measure the SMBH masses of five z ∼ 2 Hot DOGs via broad Hα emission lines, using Keck/MOSFIRE and Gemini/FLAMINGOS-2. We detect broad Hα emission in all five Hot DOGs. We find substantial corresponding SMBH masses for these Hot DOGs (∼ 10 9 M ), and their derived Eddington ratios are close to unity. These z ∼ 2 Hot DOGs are the most luminous AGNs for their BH masses, suggesting they are accreting at the maximum rates for their BHs. A similar property is found for known z ∼ 6 quasars. Our results are consistent with scenarios in which Hot DOGs represent a transitional, high-accretion phase between obscured and unobscured quasars. Hot DOGs may mark a special evolutionary stage before the red quasar and optical quasar phases, and they may be present at other cosmic epochs.

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Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC 7793 P13

Cited by 315 publications

References 21 publications

The Broadband Spectral Variability of Holmberg IX X-1

The Broadband Spectral Variability of Holmberg IX X-1

Formation of Double Neutron Star Systems

Eddington-limited Accretion in z ∼ 2 WISE-selected Hot, Dust-obscured Galaxies

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