The Nature of Soft Excess in ESO 362-G18 Revealed by XMM-Newton and NuSTAR Spectroscopy

Xu, Yerong; García, Javier A.; Walton, D. J.; Connors, Riley; Madsen, Kristin K.; Harrison, Fiona A.

doi:10.3847/1538-4357/abf430

Cited by 32 publications

(34 citation statements)

References 116 publications

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“…Jiang et al 2018;García et al 2019). If in reality there is indeed a warm corona, its presence would make it more difficult to constrain the soft X-ray shape of the reflection spectrum (Xu et al 2021). Since we believe our models to be most robust for E 3 keV, we ran an alternative fit ignoring E < 3 keV (Model 3), and found that the 3σ error on H 0 almost doubles (dH 0 ≈ 60 km s −1 Mpc −1 ) compared to the other fits.…”

Section: Soft X-raysmentioning

confidence: 99%

On measuring the Hubble constant with X-ray reverberation mapping of active galactic nuclei

Ingram

Mastroserio

Klis

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We show that X-ray reverberation mapping can be used to measure the distance to type 1 active galactic nuclei (AGNs). This is because X-ray photons originally emitted from the ‘corona’ close to the black hole irradiate the accretion disc and are re-emitted with a characteristic ‘reflection’ spectrum that includes a prominent ∼6.4 keV iron emission line. The shape of the reflection spectrum depends on the irradiating flux, and the light-crossing delay between continuum photons observed directly from the corona and the reflected photons constrains the size of the disc. Simultaneously modelling the X-ray spectrum and the time delays between photons of different energies therefore constrains the intrinsic reflected luminosity, and the distance follows from the observed reflected flux. Alternatively, the distance can be measured from the X-ray spectrum alone if the black hole mass is known. We develop a new model of our reltrans X-ray reverberation mapping package, called rtdist, that has distance as a model parameter. We simulate a synthetic observation that we fit with our new model, and find that this technique applied to a sample of ∼25 AGNs can be used to measure the Hubble constant with a 3σ statistical uncertainty of ∼6 km s−1Mpc−1. Since the technique is completely independent of the traditional distance ladder and the cosmic microwave background radiation, it has the potential to address the current tension between them. We discuss sources of modelling uncertainty, and how they can be addressed in the near future.

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Section: Soft X-raysmentioning

confidence: 99%

On measuring the Hubble constant with X-ray reverberation mapping of active galactic nuclei

Ingram

Mastroserio

Klis

et al. 2021

Monthly Notices of the Royal Astronomical Society

Self Cite

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show abstract

“…Jiang et al 2018;García et al 2019). If in reality there is indeed a warm corona, its presence would make it more difficult to constrain the soft X-ray shape of the reflection spectrum (Xu et al 2021). Since we believe our models to be most robust for 𝐸 3 keV, we ran an alternative fit ignoring 𝐸 < 3 keV (Model 3), and found that the 3𝜎 error on 𝐻 0 almost doubles (𝑑𝐻 0 ≈ 60 km s −1 Mpc −1 ) compared to the other fits.…”

Section: Soft X-raysmentioning

confidence: 99%

On measuring the Hubble constant with X-ray reverberation mapping of active galactic nuclei

Ingram,

Mastroserio,

van der Klis

et al. 2021

Preprint

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We show that X-ray reverberation mapping can be used to measure the distance to type 1 active galactic nuclei (AGNs). This is because X-ray photons originally emitted from the 'corona' close to the black hole irradiate the accretion disc and are re-emitted with a characteristic 'reflection' spectrum that includes a prominent ∼ 6.4 keV iron emission line. The shape of the reflection spectrum depends on the irradiating flux, and the light-crossing delay between continuum photons observed directly from the corona and the reflected photons constrains the size of the disc. Simultaneously modelling the X-ray spectrum and the time delays between photons of different energies therefore constrains the intrinsic reflected luminosity, and the distance follows from the observed reflected flux. Alternatively, the distance can be measured from the X-ray spectrum alone if the black hole mass is known. We develop a new model of our X-ray reverberation mapping package, called , that has distance as a model parameter. We simulate a synthetic observation that we fit with our new model, and find that this technique applied to a sample of ∼ 25 AGNs can be used to measure the Hubble constant with a 3𝜎 statistical uncertainty of ∼ 6 km s −1 Mpc −1 . Since the technique is completely independent of the traditional distance ladder and the cosmic microwave background radiation, it has the potential to address the current tension between them. We discuss sources of modelling uncertainty, and how they can be addressed in the near future.

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“…The properties of the inner accretion discs of AGNs are measured through X-ray reflection spectra, which show a soft X-ray excess below ∼ 2 keV, a broad emission profile due to Fe K lines at ∼ 6.4 − 7.1 keV, and Compton hump above 10 keV (e.g. Marinucci et al 2014;Matt et al 2014;Zoghbi et al 2015;García et al 2019;Xu et al 2021). The physical modeling of these features provides direct probes for the inner disc atmosphere and black hole spin (e.g.…”

Section: Introductionmentioning

confidence: 99%

High-density disc reflection spectroscopy of low-mass active galactic nuclei

Mallick,

Fabian,

García

et al. 2022

Preprint

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The standard alpha-disc model predicts an anti-correlation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in higher mass (M BH > 10 6 M ⊙ ) active galactic nuclei (AGNs). In this work, we test the predictions of the alpha-disc model and study the properties of the inner accretion flow for the low-mass end (M BH ≈ 10 5−6 M ⊙ ) of AGNs. We utilize a new high-density disc reflection model where the density parameter varies from n e = 10 15 to 10 20 cm −3 and apply it to the broadband X-ray (0.3−10 keV) spectra of the low-mass AGN sample. The sources span a wide range of Eddington fractions and are consistent with being sub-Eddington or near-Eddington. The X-ray spectra reveal a soft X-ray excess below ∼ 1.5 keV which is well modeled by high-density reflection from an ionized accretion disc of density n e ∼ 10 18 cm −3 on average. The results suggest a radiation pressure-dominated disc with an average of 70 per cent fraction of the disc power transferred to the corona, consistent with that observed in higher mass AGNs. We show that the disc density higher than 10 15 cm −3 can result from the radiation pressure compression when the disc surface does not hold a strong magnetic pressure gradient. We find tentative evidence for a drop in black hole spin at low-mass regimes.

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The Nature of Soft Excess in ESO 362-G18 Revealed by XMM-Newton and NuSTAR Spectroscopy

Cited by 32 publications

References 116 publications

On measuring the Hubble constant with X-ray reverberation mapping of active galactic nuclei

On measuring the Hubble constant with X-ray reverberation mapping of active galactic nuclei

On measuring the Hubble constant with X-ray reverberation mapping of active galactic nuclei

High-density disc reflection spectroscopy of low-mass active galactic nuclei

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