CLOUDY 90: Numerical Simulation of Plasmas and Their Spectra

Ferland, Gary J.; Korista, K. T.; Verner, D. A.; Ferguson, Jason W.; Kingdon, J. B.; Verner, E. M.

doi:10.1086/316190

Cited by 2,426 publications

(2,443 citation statements)

References 164 publications

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“…Our theoretical results, obtained for ions in both the ground and metastable states, have been compared with high-resolution experimental measurements and with other theoretical methods. They should be suitable for incorporation into astrophysical modeling codes such as CLOUDY [57,58], XSTAR [20], and AtomDB [59] used to numerically simulate the thermal and ionization structures of ionized astrophysical nebulae.…”

Section: Discussionmentioning

confidence: 99%

K-shell photoionization of O^4 +and O^5 +ions: experiment and theory

McLaughlin

Bizau

Cubaynes

et al. 2016

Mon. Not. R. Astron. Soc.

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Absolute cross sections for the single and double K-shell photoionization of carbonlike O 2+ and nitrogenlike O + ions were measured in the 526-620-eV photon energy range by employing the ion-photon merged-beam technique at the SOLEIL synchrotron radiation facility. High-resolution spectroscopy up to E/ E ≈ 5300 was achieved. Rich resonance structures observed in the experimental spectra are analyzed and identified with the aid of R-matrix and multiconfiguration Dirac-Fock (MCDF) methods. For these two atomic oxygen ions of particular astrophysical interest we characterized the strong 1s → 2p and the weaker 1s → np (n > 2) resonances observed. A detailed comparison of the energies of the 1s → 2p resonances in the first members of the oxygen isonuclear sequence measured by synchrotron based experiments and the Chandra and XMM-Newton x-ray satellites is presented.

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Section: Discussionmentioning

confidence: 99%

K-shell photoionization of O^4 +and O^5 +ions: experiment and theory

McLaughlin

Bizau

Cubaynes

et al. 2016

Mon. Not. R. Astron. Soc.

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“…In order to estimate the contribution from a photo-ionized plasma near an INS, as mentioned above, we have used the widespread photoionization code CLOUDY (calculations were performed with version 07.02.02 of Cloudy, as described by Ferland et al 1998). Despite the restrictions (luminosity of the ionizing source, ionization parameter, i.e.…”

Section: Discussionmentioning

confidence: 99%

XMM-Newton RGS spectrum of RX J0720.4-3125: an absorption feature at 0.57 keV

Hambaryan¹,

Neuhäuser²,

Haberl

et al. 2009

A&A

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Aims. By measuring the gravitational redshift of spectral features in the spectrum of thermal radiation emitted from neutron stars, useful constraints for the equation of state of superdense matter can be obtained via an estimate of the mass-to-radius ratio. We searched for spectral line features in the high-resolution X-ray spectrum of the isolated neutron star RX J0720.4−3125. Methods. Our target was observed by XMM-Newton on many occasions. We used the XMM-Newton SAS task rgscombine in order to create a co-added RGS spectrum of RX J0720.4−3125. We modeled the resulting spectrum with absorbed blackbody radiation with a Gaussian absorption features using the XSPEC package. Results. We found a narrow absorption feature at 0.57 keV in the co-added RGS spectrum of the isolated neutron star RX J0720.4−3125 with an equivalent width of 1.35 ± 0.3 eV and FWHM ∼ 6.0 eV. The feature was identified with an absorption line of highly ionized oxygen O vii, most probably originating in the ambient medium of RX J0720.4−3125. An extensive investigation with the photo-ionization code CLOUDY indicates the possibility that the optical flux excess observed in the spectrum of RX J0720.4−3125 at least partially originates in a relatively dense (e.g. n H ∼ 10 8 cm −3 ) slab, located in the vicinity of the neutron star (e.g. ∼10 10 cm).

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“…Noting that He star disruptions would be exceedingly rare, Guillochon et al (2014) instead argued for the disruption of a normal main-sequence star but with the hydrogen line emission suppressed by photoionization effects (e.g., Korista & Goad 2004). Gaskell & Rojas Lobos (2014) performed new calculations using the photoionization code CLOUDY (Ferland et al 1998(Ferland et al , 2013 and showed that, if the lines are optically thick, radiation transport effects may reduce the hydrogen emission line strength. However, a separate CLOUDY parameter study performed by Strubbe & Murray (2015) disputed this interpretation, concluding that, for the conditions relevant to TDEs, hydrogen lines would not be suppressed enough to be consistent with the observations of PS1-10jh.…”

Section: Introductionmentioning

confidence: 99%

The X-Ray Through Optical Fluxes and Line Strengths of Tidal Disruption Events

Roth

Kasen

Guillochon

et al. 2016

ApJ

206

244

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We study the emission from tidal disruption events (TDEs) produced as radiation from black hole accretion propagates through an extended, optically thick envelope formed from stellar debris. We analytically describe key physics controlling spectrum formation, and present detailed radiative transfer calculations that model the spectral energy distribution and optical line strengths of TDEs near peak brightness. The steady-state transfer is coupled to a solver for the excitation and ionization states of hydrogen, helium, and oxygen (as a representative metal), without assuming local thermodynamic equilibrium. Our calculations show how an extended envelope can reprocess a fraction of soft X-rays and produce the observed optical fluxes of the order of 10 43 erg s −1 , with an optical/UV continuum that is not described by a single blackbody. Variations in the mass or size of the envelope may help explain how the optical flux changes over time with roughly constant color. For high enough accretion luminosities, X-rays can escape to be observed simultaneously with the optical flux. Due to optical depth effects, hydrogen Balmer line emission is often strongly suppressed relative to helium line emission (with He II-to-H line ratios of at least 5:1 in some cases) even in the disruption of a solar-composition star. We discuss the implications of our results to understanding the type of stars destroyed in TDEs and the physical processes responsible for producing the observed flares.

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CLOUDY 90: Numerical Simulation of Plasmas and Their Spectra

Cited by 2,426 publications

References 164 publications

K-shell photoionization of O^4 +and O^5 +ions: experiment and theory

K-shell photoionization of O^4 +and O^5 +ions: experiment and theory

XMM-Newton RGS spectrum of RX J0720.4-3125: an absorption feature at 0.57 keV

The X-Ray Through Optical Fluxes and Line Strengths of Tidal Disruption Events

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CLOUDY 90: Numerical Simulation of Plasmas and Their Spectra

Cited by 2,426 publications

References 164 publications

K-shell photoionization of O4 +and O5 +ions: experiment and theory

K-shell photoionization of O4 +and O5 +ions: experiment and theory

XMM-Newton RGS spectrum of RX J0720.4-3125: an absorption feature at 0.57 keV

The X-Ray Through Optical Fluxes and Line Strengths of Tidal Disruption Events

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K-shell photoionization of O^4 +and O^5 +ions: experiment and theory

K-shell photoionization of O^4 +and O^5 +ions: experiment and theory