The properties of the X-ray corona in the distant (<i>z</i>= 3.91) quasar APM 08279+5255

Bertola, E.; Vignali, C.; Lanzuisi, G.; Dadina, M.; Cappi, M.; Gilli, R.; Matzeu, G. A.; Chartas, G.; Piconcelli, E.; Comastri, A.

doi:10.1051/0004-6361/202142642

Cited by 7 publications

(8 citation statements)

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“…Therefore pair production can become a runaway process in a sufficiently hot and compact corona, and the mechanism can act as a natural thermostat. This theory is demonstrated by many quasars sitting along the pair production balance line in the compactness versus temperature (l-θ) diagram, which is translated into observables in the L X -E cut diagram (Bertola et al 2022). We show RXJ1131 in the L X -E cut plane compared to other quasars collected by Bertola et al (2022) and references therein in Figure 6, where the X-ray luminosity has been corrected by a total magnification factor μ AGN = 48.2 (Paraficz et al 2018), and RXJ1131 lies on the allowable parameter space without violating the electron pair production limit.…”

Section: Resultsmentioning

confidence: 96%

“…This theory is demonstrated by many quasars sitting along the pair production balance line in the compactness versus temperature (l-θ) diagram, which is translated into observables in the L X -E cut diagram (Bertola et al 2022). We show RXJ1131 in the L X -E cut plane compared to other quasars collected by Bertola et al (2022) and references therein in Figure 6, where the X-ray luminosity has been corrected by a total magnification factor μ AGN = 48.2 (Paraficz et al 2018), and RXJ1131 lies on the allowable parameter space without violating the electron pair production limit. This lens model is based on the point-like (quasar) image position from the CO emission measured by the Atacama Large Millimeter/submillimeter Array, and the model is consistent with those based on the Hubble Space Telescope or 2.2μm quasar positions.…”

Section: Resultsmentioning

confidence: 96%

“…This is consistent with a picture that the reflection is occurring in a region in the accretion disk with a range larger than the soft X-ray size in RXJ1131. Remote reflection in the outer region of the accretion disk or torus as the majority of the reflection region in RXJ1131 can still be viable because of large measurement (Bertola et al 2022). The green and blue curves represent the boundary line for runaway pair production presented as a polynomial in Ricci et al (2018).…”

Section: Resultsmentioning

confidence: 99%

“…Figure6. X-ray luminosity vs. cutoff energy from a selection of quasars(Bertola et al 2022). The green and blue curves represent the boundary line for runaway pair production presented as a polynomial inRicci et al (2018).…”

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confidence: 99%

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NuSTAR Hard X-Ray Monitoring of Gravitationally Lensed Quasar RX J1131–1231

DeFrancesco,

Dai,

Mitchell

et al. 2023

ApJ

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The X-ray emission from active galactic nuclei is believed to come from a combination of inverse Compton scattering of photons from the accretion disk and reprocessing of the direct X-ray emission by reflection. We present hard (10–80 keV) and soft (0.5–8 keV) X-ray monitoring of a gravitationally lensed quasar RX J1131−1231 (hereafter RXJ1131) with NuSTAR, Swift, and XMM-Newton between 2016 June 10 and 2020 November 30. Comparing the amplitude of quasar microlensing variability at the hard and soft bands allows a size comparison, where larger sources lead to smaller microlensing variability. During the period between 2018 June 6 and 2020 November 30, where both the hard and soft light curves are available, the hard and soft bands varied by factors of 3.7 and 5.5, respectively, with rms variability of 0.40 ± 0.05 and 0.57 ± 0.02. Both the variability amplitude and rms are moderately smaller for the hard X-ray emission, indicating that the hard X-ray emission is moderately larger than the soft X-ray emission region. We found the reflection fraction from seven joint hard and soft X-ray monitoring epochs is effectively consistent with a constant with low significance variability. After decomposing the total X-ray flux into direct and reprocessed components, we find a smaller variability amplitude for the reprocessed flux compared to the direct emission. The power-law cutoff energy is constrained at 96 − 24 + 47 keV, which positions the system in the allowable parameter space due to the pair production limit.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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NuSTAR Hard X-Ray Monitoring of Gravitationally Lensed Quasar RX J1131–1231

DeFrancesco,

Dai,

Mitchell

et al. 2023

ApJ

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“…It is common to assume that the coronal plasma is thermal. However, several AGN show electron temperatures that are much lower than expected for a purely thermal pair plasma (see, e.g., Baloković et al, 2015;Ursini et al, 2016;Kara et al, 2017;Tortosa et al, 2018;Reeves et al, 2021;Bertola et al, 2022). These low temperatures could be indicative of a hybrid plasma composed of a mixture of thermal and non-thermal particles (Ghisellini et al, 1993;Zdziarski et al, 1993;Fabian et al, 2017).…”

Section: The Heating and Cooling Mechanisms Of The X-ray Coronamentioning

confidence: 96%

The high energy X-ray probe (HEX-P): probing the physics of the X-ray corona in active galactic nuclei

Kammoun,

Lohfink,

Masterson

et al. 2024

Front. Astron. Space Sci.

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The hard X-ray emission in active galactic nuclei (AGN) and black hole X-ray binaries is thought to be produced by a hot cloud of electrons referred to as the corona. This emission, commonly described by a power law with a high-energy cutoff, is suggestive of Comptonization by thermal electrons. While several hypotheses have been proposed to explain the origin, geometry, and composition of the corona, we still lack a clear understanding of this fundamental component. NuSTAR has been playing a key role improving our knowledge of X-ray coronæ thanks to its unprecedented sensitivity above 10 keV. However, these constraints are limited to bright, nearby sources. The High Energy X-ray Probe (HEX-P) is a probe-class mission concept combining high spatial resolution X-ray imaging and broad spectral coverage (0.2–80 keV) with a sensitivity superior to current facilities. In this paper, we highlight the major role that HEX-P will play in further advancing our insights of X-ray coronæ notably in AGN. We demonstrate how HEX-P will measure key properties and track the temporal evolution of coronæ in unobscured AGN. This will allow us to determine their electron distribution and test the dominant emission mechanisms. Furthermore, we show how HEX-P will accurately estimate the coronal properties of obscured AGN in the local Universe, helping address fundamental questions about AGN unification. In addition, HEX-P will characterize coronæ in a large sample of luminous quasars at cosmological redshifts for the first time and track the evolution of coronæ in transient systems in real time. We also demonstrate how HEX-P will enable estimating the coronal geometry using spectral-timing techniques. HEX-P will thus be essential to understand the evolution and growth of black holes over a broad range of mass, distance, and luminosity, and will help uncover the black holes’ role in shaping the Universe.

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Breaking the rules at z ≃ 0.45: The rebel case of RBS 1055

Marinucci

Vietri

Piconcelli

et al. 2022

A&A

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Context. Very luminous quasars are unique sources for studying the circumnuclear environment around supermassive black holes. Several components contribute to the overall X-ray spectral shape of active galactic nuclei (AGN). The hot (kTe = 50 − 100 keV) and warm (kTe = 0.1 − 1 keV) coronae are responsible for the hard and soft power-law continua, while the circumnuclear toroidal reflector accounts for the Fe Kα emission line and the associated Compton hump. However, all these spectral features are simultaneously observed only in a handful of sources above z ≃ 0.1. Aims. An ideal astrophysical laboratory for this investigation is the quasar RBS 1055, at z ≃ 0.45. With a luminosity L2 − 10 keV = 2 × 1045 erg s−1, it is the brightest radio-quiet quasar from the ROSAT Bright Survey. Despite the known anti-correlation between the equivalent width (EW) of the narrow neutral Fe Kα line and L2 − 10 keV, an intense Fe Kα was previously detected for this source. Methods. We report findings based on a long (250 ks) NuSTAR observation performed in March 2021 and archival XMM-Newton pointings (185 ks) taken in July 2014. We also analyzed an optical spectrum of the source taken with the Double Spectrograph at the Palomar Observatory quasi-simultaneously to the NuSTAR observations. Results. We find that the two-corona model, in which a warm and hot corona coexist, well reproduces the broad band spectrum of RBS 1055, with temperatures kTe = 0.12−0.03+0.08 keV, kTe = 30−10+40 keV and Thomson optical depths τ = 30−10+15 and τ = 3.0−1.4+1.0 for the former and the latter component, respectively. We confirm the presence of an intense Fe Kα emission line (EW = 55 ± 6 eV) and find, when a toroidal model is considered for reproducing the Compton reflection, a Compton-thin solution with NH = (3.2−0.8+0.9) × 1023 cm−2 for the circumnuclear reflector. A detailed analysis of the optical spectrum reveals a likely peculiar configuration of our line of sight with respect to the nucleus, and the presence of a broad [O III] component tracing outflows in the Narrow Line Region, with a velocity shift v = 1500 ± 100 km s−1, leading to a mass outflow rate Ṁout = 25.4 ±1.5 M⊙ yr−1 and outflow kinetic power normalized by the bolometric luminosity Ēkin/LBol ∼ 0.33%. We estimate the BH mass to be in the range 2.8 × 108–1.2 × 109 M⊙, according to different broad line region emission lines, with an average value of ⟨MBH⟩ = 6.5 × 108 M⊙. Conclusions. With an Fe Kα that is 3σ above the value predicted from the EW–L2 − 10 keV relation and an extreme source brightness at 2 keV (a factor 10−15 higher than the one expected from the optical/UV), we can confirm that RBS 1055 is an outlier in the X-rays compared to other objects in the same luminosity and redshift range.

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The properties of the X-ray corona in the distant (z= 3.91) quasar APM 08279+5255

Cited by 7 publications

References 84 publications

NuSTAR Hard X-Ray Monitoring of Gravitationally Lensed Quasar RX J1131–1231

NuSTAR Hard X-Ray Monitoring of Gravitationally Lensed Quasar RX J1131–1231

The high energy X-ray probe (HEX-P): probing the physics of the X-ray corona in active galactic nuclei

Breaking the rules at z ≃ 0.45: The rebel case of RBS 1055

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