Photoionization and High‐Density Gas

Kallman, T. R.; Bautista, M. A.

doi:10.1086/319184

Cited by 617 publications

(605 citation statements)

References 29 publications

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“…The variability above $2 keV can be explained by flux changes of a single component, a scattered power law with intrinsic absorption of N H ¼ 10 22:5 cm À2 . Strong Fe K line emission would not be expected from scattering off of a highly ionized plasma ( $ 10 5 ergs cm s À1 ) where the Fe atoms are largely stripped of electrons (Kallman & Bautista 2001).…”

Section: X-ray Variability and Spectral Resultsmentioning

confidence: 99%

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

Gallagher

Brandt

Chartas

et al. 2002

ApJ

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With 40 ks of Chandra ACIS-S3 exposure, new information on both the starburst and QSO components of the X-ray emission of Markarian 231, an ultraluminous infrared galaxy and broad absorption line QSO, has been obtained. The bulk of the X-ray luminosity is emitted from an unresolved nuclear point source, and the spectrum is remarkably hard, with the majority of the flux emitted above 2 keV. Most notably, significant nuclear variability (a decrease of $45% in approximately 6 hr) at energies above 2 keV indicates that Chandra has probed within light-hours of the central black hole. Although we concur with Maloney & Reynolds that the direct continuum is not observed, this variability coupled with the 188 eV upper limit on the equivalent width of the Fe K emission line argues against the reflection-dominated model put forth by these authors based on their ASCA data. Instead, we favor a model in which a small, Compton-thick absorber blocks the direct X-rays, and only indirect, scattered X-rays from multiple lines of sight can reach the observer. Extended soft, thermal emission encompasses the optical extent of the galaxy and exhibits resolved structure. An off-nuclear X-ray source with a 0.35-8.0 keV luminosity of L X ¼ 7 Â 10 39 ergs s À1 , consistent with the ultraluminous X-ray sources in other nearby starbursts, is detected. We also present an unpublished Faint Object Spectrograph spectrum from the Hubble Space Telescope archive showing the broad C iv absorption.

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Section: X-ray Variability and Spectral Resultsmentioning

confidence: 99%

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

Gallagher

Brandt

Chartas

et al. 2002

ApJ

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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: Resultsmentioning

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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“…To this end, we created a grid of self-consistent photoionization models with XSTAR ( Kallman & Bautista 2001). These were read into XSPEC as a multiplicative model to fit the HEG spectral data.…”

Section: Photo-ionization Modeling Of the Chandra Datamentioning

confidence: 99%

Disc reflection and a possible disc wind during a soft X-ray state in the neutron star low-mass X-ray binary 1RXS J180408.9–342058

Degenaar

Altamirano

Parker

et al. 2016

Mon. Not. R. Astron. Soc.

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ABSTRACT1RXS J180408.9-342058 is a transient neutron star low-mass X-ray binary that exhibited a bright accretion outburst in 2015. We present NuSTAR, Swift, and Chandra observations obtained around the peak brightness of this outburst. The source was in a soft X-ray spectral state and displayed an X-ray luminosity of L X ≃(2 − 3) × 10 37 (D/5.8 kpc) 2 erg s −1 (0.5-10 keV). The NuSTAR data reveal a broad Fe-K emission line that we model as relativistically broadened reflection to constrain the accretion geometry. We found that the accretion disk is viewed at an inclination of i≃27 • -35 • and extended close to the neutron star, down to R in ≃5-7.5 gravitational radii (≃11-17 km). This inner disk radius suggests that the neutron star magnetic field strength is B 2×10 8 G. We find a narrow absorption line in the Chandra/HEG data at an energy of ≃7.64 keV with a significance of ≃4.8σ. This feature could correspond to blue-shifted Fe XXVI and arise from an accretion disk wind, which would imply an outflow velocity of v out ≃0.086c (≃25 800 km s −1 ). However, this would be extreme for an X-ray binary and it is unclear if a disk wind should be visible at the low inclination angle that we infer from our reflection analysis. Finally, we discuss how the X-ray and optical properties of 1RXS J180408.9-342058 are consistent with a relatively small (P orb 3 hr) binary orbit.

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Photoionization and High‐Density Gas

Cited by 617 publications

References 29 publications

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

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

Disc reflection and a possible disc wind during a soft X-ray state in the neutron star low-mass X-ray binary 1RXS J180408.9–342058

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Photoionization and High‐Density Gas

Cited by 617 publications

References 29 publications

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

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

Disc reflection and a possible disc wind during a soft X-ray state in the neutron star low-mass X-ray binary 1RXS J180408.9–342058

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