The first simultaneous X-ray broadband view of Mrk 110 with <i>XMM-Newton</i> and <i>NuSTAR</i>

Porquet, D.; Reeves, J. N.; Grosso, N.; Braito, V.; Lobban, A.

doi:10.1051/0004-6361/202141577

Cited by 22 publications

(14 citation statements)

References 91 publications

(120 reference statements)

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“…The Nuclear Spectroscopic Telescope Array (NuSTAR; Harrison et al 2013) is the first hard X-ray telescope with direct-imaging capability above 10 keV. With its broad spectral coverage of 3-78 keV, NuSTAR has enabled the measurements (or lower limits) of E cut /kT e in a number of AGNs (e.g., Ballantyne et al 2014;Matt et al 2015;Ursini et al 2016;Kamraj et al 2018;Tortosa et al 2018;Molina et al 2019;Rani et al 2019;Panagiotou & Walter 2020;Akylas & Georgantopoulos 2021;Hinkle & Mushotzky 2021;Porquet et al 2021;Kamraj et al 2022). Meanwhile, variations of E cut /T e are also reported in a few individual sources (e.g., Keek & Ballantyne 2016;Zhang et al 2018;Kang et al 2021).…”

Section: Introductionmentioning

confidence: 99%

The X-Ray Coronae in NuSTAR Bright Active Galactic Nuclei

Wang

2022

ApJ

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We present a systematic and uniform analysis of NuSTAR data of a sample of 60 SWIFT BAT-selected AGNs with 10–78 keV signal-to-noise ratio (S/N) > 50, 10 of which are radio loud. We measure their high-energy cutoff E cut or coronal temperature T e using three different spectral models to fit their NuSTAR spectra and show that a threshold in NuSTAR spectral S/N is essential for such measurements. High-energy spectral breaks are detected in the majority of the sample, and for the rest, strong constraints on E cut or T e are obtained. Strikingly, we find extraordinarily large E cut lower limits (>400 keV, up to >800 keV) in 10 radio-quiet sources, whereas we find none in the radio-loud sample. Consequently and surprisingly, we find a significantly larger mean E cut/T e of radio-quiet sources compared with radio-loud ones. The reliability of these measurements is carefully inspected and verified with simulations. We find a strong positive correlation between E cut and photon index Γ, which cannot be attributed to the parameter degeneracy. The strong dependence of E cut on Γ, which could fully account for the discrepancy of the E cut distribution between radio-loud and radio-quiet sources, indicates that the X-ray coronae in AGNs with steeper hard X-ray spectra have on average higher temperature and thus smaller opacity. However, no prominent correlation is found between E cut and λ edd. In the l–Θ diagram, we find a considerable fraction of sources lie beyond the boundaries of forbidden regions due to runaway pair production, posing (stronger) challenges to various (flat) coronal geometries.

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Section: Introductionmentioning

confidence: 99%

The X-Ray Coronae in NuSTAR Bright Active Galactic Nuclei

Wang

2022

ApJ

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“…kT e ∼ 15 keV in Akn 564 (Kara et al 2017;Barua et al 2020), kT e ∼ 3-22 keV in IRAS 04416+1215 (Tortosa et al 2022), kT e ∼ 21−31 keV in Mrk 110 (Porquet et al 2021), and kT e ∼ 20 keV in ESO 362-G18 (Xu et al 2021). The broadband X-ray power-law flux in the 2-500 keV band ( f xpl ) decreased by a factor of ∼4 from 2018 June to 2019 August (Figure 3(e)).…”

Section: Resultsmentioning

confidence: 94%

Thermal Comptonization in a Changing Corona in the Changing-look Active Galaxy NGC 1566

Tripathi

Dewangan

2022

ApJ

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We present broadband UV/X-ray spectral variability of the changing-look active galactic nucleus (AGN) NGC 1566, based on simultaneous near-ultraviolet and X-ray observations performed by the XMM-Newton, Swift, and NuSTAR satellites at five different epochs during the declining phase of the 2018 outburst. We found that the accretion disk, soft X-ray excess, and X-ray power-law components were extremely variable. Additionally, the X-ray power-law flux was correlated with both the soft excess plus disk and the pure disk fluxes. Our finding shows that at high-flux levels the soft X-ray excess and the disk emission both provided the seed photons for thermal Comptonization in the hot corona, whereas at low-flux levels, where the soft excess was absent, the pure disk emission alone provided the seed photons. The X-ray power-law photon index was only weakly variable (ΔΓhot ≤ 0.06), and it was not well correlated with the X-ray flux over the declining timescale. On the other hand, we found that the electron temperature of the corona increased from ∼22 to ∼200 keV with the decreasing numbers of seed photons from 2018 June to 2019 August. At the same time, the optical depth of the corona decreased from τ hot ∼ 4 to ∼0.7, and the scattering fraction increased from ∼1% to ∼10%. These changes suggest structural changes in the hot corona, such as it was growing in size and becoming hotter with the decreasing accretion rate during the declining phase. The AGN is most likely evolving with a decreasing accretion rate toward a state similar to the low/hard state of black hole X-ray binaries.

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“…This indicates that during the high flux states, the soft excess and the disk emission both provided the seed photon for thermal Comptonization in the hot corona, but a larger contribution came from the soft excess than the pure disk emission which made the corona to be sufficiently cooler at the outburst-peak (∼ 22 keV). The strong soft excess may be responsible for the low temperature of the hot corona in some narrow-line Seyfert 1 galaxies e.g., kT e ∼ 15 keV in Akn 564 (Kara et al 2017;Barua et al 2020), kT e ∼ 3 − 22 keV in IRAS 04416+1215 (Tortosa et al 2022), kT e ∼ 21 − 31 keV in Mrk 110 (Porquet et al 2021), kT e ∼ 20 keV in ESO 362-G18 (Xu et al 2021). The broadband X-ray power-law flux in the 2-500 keV band (f xpl ) decreased by a factor of ∼ 4 from June 2018 to August 2019 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Thermal Comptonization in a changing corona in the changing-look active galaxy NGC 1566

Tripathi,

Dewangan

2022

Preprint

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We present broadband UV/X-ray spectral variability of the changing-look active galactic nucleus NGC 1566 based on simultaneous near-ultraviolet (NUV) and X-ray observations performed by XMM-Newton, Swift, and NuSTAR satellites at five different epochs during the declining phase of the 2018 outburst. We found that the accretion disk, soft X-ray excess, and the X-ray power-law components were extremely variable. Additionally, the X-ray power-law flux was correlated with both the soft excess plus disk, and the pure disk fluxes. Our finding shows that at high flux levels the soft X-ray excess and the disk emission both provided the seed photons for thermal Comptonization in the hot corona, whereas at low flux levels where the soft excess was absent, the pure disk emission alone provided the seed photons. The X-ray power-law photon-index was only weakly variable (∆Γ hot ≤ 0.06) and it was not well correlated with the X-ray flux over the declining timescale. On the other hand, we found that the electron temperature of the corona increased from ∼ 22 to ∼ 200 keV with decreasing number of seed photons from June 2018 to August 2019. At the same time, the optical depth of the corona decreased from τ hot ∼ 4 to ∼ 0.7, and the scattering fraction increased from ∼ 1% to ∼ 10%. These changes suggest structural changes in the hot corona such that it grew in size and became hotter with decreasing accretion rate during the declining phase. The AGN is most likely evolving with decreasing accretion rate towards a state similar to the low/hard state of black hole X-ray binaries.

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The first simultaneous X-ray broadband view of Mrk 110 with XMM-Newton and NuSTAR

Cited by 22 publications

References 91 publications

The X-Ray Coronae in NuSTAR Bright Active Galactic Nuclei

The X-Ray Coronae in NuSTAR Bright Active Galactic Nuclei

Thermal Comptonization in a Changing Corona in the Changing-look Active Galaxy NGC 1566

Thermal Comptonization in a changing corona in the changing-look active galaxy NGC 1566

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