The Interaction of X-Ray Sources with Optically Thick Environments

Tarter, C. Bruce; Salpeter, E. E.

doi:10.1086/150027

Cited by 38 publications

(18 citation statements)

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“…This is at a distance of only about half of the expected average distance of the BLR for a QSO of the given L bol (in accordance to what has been found for the eclipsing cloud in NGC 1365 d ∼ 100r g , Risaliti et al 2007). An even looser limit is obtained following Tarter et al (1969).…”

Section: Two Best-fit Scenariosmentioning

confidence: 99%

XMM-Newtonreveals a Seyfert-like X-ray spectrum in thez= 3.6 QSO B1422+231

Dadina

Vignali²,

Cappi

et al. 2016

A&A

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Context. Matter flows from the central regions of quasi-stellar objects (QSOs) during their active phases are probably responsible for the properties of the super-massive black holes and those of the bulges of host galaxies. To understand how this mechanism works, we need to characterize the geometry and the physical state of the accreting matter at cosmological redshifts, when QSO activity is at its peak. Aims. We aim to use X-ray data to probe the matter inflow at the very center of a QSO at z = 3.62. While complex absorption, the iron K emission line, reflection hump, and high-energy cutoff are known to be almost ubiquitous in nearby active galactic nuclei (AGN), only a few distant objects are known to exhibit some of them.Methods. The few high-quality spectra of distant QSO were collected by adding sparse pointings of single objects obtained during X-ray monitoring campaigns. This could have introduced spurious spectral features due to source variability and/or microlensing. To avoid such problems, we decided to collect a single-epoch and high-quality X-ray spectrum of a distant AGN. We thus picked up the z = 3.62 QSO B1422+231, whose flux, enhanced by gravitationally lensing, is proven to be among the brightest lensed QSOs in X-rays (F 2−10 keV ∼ 10 −12 erg s −1 cm −2 ). Results. The X-ray spectrum of B1422+231 is found to be very similar to the one of a typical nearby Seyfert galaxy. Neutral absorption is clearly detected (N H ∼ 5 × 10 21 cm −2 at the redshift of the source), while a strong absorption edge is measured at E ∼ 7.5 keV with an optical depth of τ ∼ 0.14. We also find hints of the FeKα line in emission at E ∼ 6.4 keV line (EW < ∼ 70 eV), and a hump is detected in the E ∼ 15−20 keV energy band (rest frame) in excess of what is predicted by a simple absorbed power-law. Conclusions. The spectrum can best be modeled with two rather complex models; one assumes ionized and partially covering matter along the line of sight, the other is characterized by a reflection component. We argue that reflection seems more plausible here on a statistical basis. In this scenario, the primary emission of B1422+231 is most probably dominated by the thermal Comptonization of UV seed photons in a corona with kT ∼ 40 keV. We also detected a reflection component with relative direct-to-reflect normalization r ∼ 1. These findings confirm that gravitational lensing is suitable for obtaining good-quality X-ray spectral information of QSOs at high-z, moreover, they support the idea that the same general picture characterizing AGN in the nearby Universe is also valid at high redshift.

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Section: Two Best-fit Scenariosmentioning

confidence: 99%

XMM-Newtonreveals a Seyfert-like X-ray spectrum in thez= 3.6 QSO B1422+231

Dadina

Vignali²,

Cappi

et al. 2016

A&A

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“…I had told Bruce to stop working on such an unprofitable topic and to do a thesis on the interaction of X-rays with the interstellar medium, where one could hope for observational data soon. His work in this field was indeed well-received, (e.g., Tarter & Salpeter 1969), he became the director of the Livermore National Laboratory at a rather young age and generally did not suffer too much from my bad advice. Nevertheless, it took quite a while for others to get well beyond Bruce's unpublished work on accretion disks, and he might have had a more exciting youth without my timid, bad advice.…”

Section: Black Hole Accretionmentioning

confidence: 95%

A Generalist Looks Back

Salpeter

2002

Annu. Rev. Astron. Astrophys.

Self Cite

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I have stayed at Cornell ever since, and I have essentially had only a single job in my whole life, but have switched fields quite often. I worked in nuclear astrophysics and in late-stellar evolution, estimated the Initial Mass Function for star formation and the metal enrichment of the interstellar medium. I suggested black hole accretion as the energy source for quasars, worked on molecule formation on dust grain surfaces, and was involved in 21-cm studies of gas clouds and disk galaxies. I collaborated with my wife on the neurobiology of the neuromuscular junction and with one of my daughters on the epidemiology of tuberculosis.

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“…The theoretical work was initiated in astrophysical calculations starting with the work of Tarter et al [34] and Tarter and Salpeter [35] who performed calculations for photoionised astrophysical plasmas. There has been considerable work in the astrophysical community since that time culminating in the development of several codes that calculate the distribution of excitation and ionisation for photoionised plasmas, such as the code CLOUDY [9].…”

Section: Broad-band Photopumpingmentioning

confidence: 99%

The effect of a radiation field on excitation and ionisation in non-LTE high energy density plasmas

Rose

2009

High Energy Density Physics

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The Interaction of X-Ray Sources with Optically Thick Environments

Cited by 38 publications

References 0 publications

XMM-Newtonreveals a Seyfert-like X-ray spectrum in thez= 3.6 QSO B1422+231

XMM-Newtonreveals a Seyfert-like X-ray spectrum in thez= 3.6 QSO B1422+231

A Generalist Looks Back

The effect of a radiation field on excitation and ionisation in non-LTE high energy density plasmas

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