On the Observational Difference Between the Accretion Disk-Corona Connections among Super- and Sub-Eddington Accreting Active Galactic Nuclei

Liu, Hezhen; Luo, B.; Brandt, W. N.; Brotherton, Michael S.; Gallagher, S. C.; Ni, Q.; Shemmer, Ohad; Timlin, J. D.

doi:10.48550/arxiv.2102.02832

Cited by 3 publications

(4 citation statements)

References 165 publications

(310 reference statements)

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“…This value is in perfect agreement with the dimensionless accretion rate from Du et al (2014). However even assuming the luminosity from Liu et al 2021, with which the value of the accretion rate would be 𝜆 Edd ∼ 4.40, the source would remain a super-Eddington accreting AGN. IRAS 04416+1215 turned out to be the most peculiar of our sample, it is classified as NLS1 galaxy, showing narrow H𝛽 line (FWHM=1670 km s −1 , Moran et al 1996) and very broad [OIII] (FWHM=1150 km s −1 , Véron-Cetty et al 2001) lines, which is typically found in sources accreting at such high Eddington accretion rates (Greene & Ho 2005;Ho 2009).…”

Section: Introductionsupporting

confidence: 74%

“…In this campaign we are carrying out to study the broadband X-ray properties of super-Eddington AGN, all the sources have new NuSTAR observations performed simultaneously with XMM-Newton or Swift-XRT. IRAS 04416+1215 has bolometric luminosity log(𝐿 bol /erg s −1 ) = 47.55, according to Castelló-Mor et al 2016 and log(𝐿 bol /erg s −1 ) = 45.52 according to Liu et al 2021. The former estimate is computed using, for the spectral energy distribution (SED) fitting procedure, the Slone & Netzer (2012) code, including the comparison of the observed SED with various combinations of disc SEDs covering the range of mass, accretion rate, spins and taking into account the correction for intrinsic reddening and host-galaxy contribution.…”

Section: Introductionmentioning

confidence: 99%

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The extreme properties of the nearby hyper-Eddington accreting Active Galactic Nucleus in IRAS 04416+1215

Tortosa,

Ricci,

Tombesi

et al. 2021

Preprint

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The physical properties of the accretion flow and of the X-ray emitting plasma, in supermassive black holes accreting at extreme Eddington rates, are still very unclear. Here we present the analysis of simultaneous XMM-Newton and NuSTAR observations of the hyper-Eddington Seyfert 1 galaxy IRAS 04416+1215, carried out in 2020. The main goal of these observations is to investigate the properties of the X-ray corona, as well as the structure of the accretion flow and of the circumnuclear environment, in this regime of extreme accretion. IRAS 04416+1215 has one of the highest Eddington ratio (𝜆 Edd 472) in the local Universe. It shows an interesting spectral shape with the presence of multi-phase absorption structure composed of three phases, whose estimate of the minimum and maximum distances suggests two different interpretations, one consistent with the three X-ray winds being co-spatial, and possibly driven by magnetohydrodynamical processes, the other consistent with the multi-phase winds being also multi-scale. The X-ray spectrum of IRAS 04416+1215 also has a prominent soft excess component and a hard X-ray emission dominated by a reflection component. Moreover, our detailed spectral analysis shows that IRAS 04416+1215 has the lowest coronal temperature measured so far by NuSTAR (𝑘𝑇 𝑒 = 3 − 22 keV, depending on the model). This is consistent with a hybrid coronal plasma, in which the primary continuum emission is driven by pair production due to high-energy tail of the energy distribution of non-thermal electrons.

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Section: Introductionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

The extreme properties of the nearby hyper-Eddington accreting Active Galactic Nucleus in IRAS 04416+1215

Tortosa,

Ricci,

Tombesi

et al. 2021

Preprint

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“…Furthermore, the correlations of the data in Figure 5 (and Table 2) indicate that 𝛼 ox correlates as strongly with He EW as it does with 𝐿 2500 , if not slightly more so, which is a notable result given that previous investigations have been unable to find another parameter that correlates as strongly with 𝛼 ox as 𝐿 2500 (e.g. Shemmer et al 2008;Liu et al 2021).…”

Section: The Interdependence Of 𝛼 Ox 𝐿 2500 and He Ewmentioning

confidence: 64%

What controls the UV-to-X-ray continuum shape in quasars?

Timlin,

Brandt,

Laor

2021

Preprint

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We present an investigation of the interdependence of the optical-to-X-ray spectral slope (𝛼 ox ), the He equivalent-width (EW), and the monochromatic luminosity at 2500 Å (𝐿 2500 ). The values of 𝛼 ox and He EW are indicators of the strength/shape of the quasar ionizing continuum, from the ultraviolet (UV; 1500-2500 Å), through the extreme ultraviolet (EUV; 300-50 Å), to the X-ray (2 keV) regime. For this investigation, we measure the He EW of 206 radio-quiet quasars devoid of broad absorption lines that have high-quality spectral observations of the UV and 2 keV X-rays. The sample spans wide redshift (≈ 0.13-3.5) and luminosity (log(𝐿 2500 ) ≈ 29.2-32.5 erg s −1 Hz −1 ) ranges. We recover the well-known 𝛼 ox -𝐿 2500 and He EW-𝐿 2500 anti-correlations, and we find a similarly strong correlation between 𝛼 ox and He EW, and thus the overall spectral shape from the UV, through the EUV, to the X-ray regime is largely set by luminosity. A significant 𝛼 ox -He EW correlation remains after removing the contribution of 𝐿 2500 from each quantity, and thus the emission in the EUV and the X-rays are also directly tied. This set of relations is surprising, since the UV, EUV, and X-ray emission are expected to be formed in three physically distinct regions. Our results indicate the presence of a redshift-independent physical mechanism that couples the continuum emission from these three different regions, and thus controls the overall continuum shape from the UV to the X-ray regime.

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“…2. Absorption on scales smaller than most of the accretion disk (e.g., due to a thick inner disk, a "failed wind", or the outflowing material itself in the case of radiation-pressure confinement; e.g., Proga & Kallman 2004;Baskin et al 2014;Ni et al 2018;Liu et al 2021) can absorb the X-ray photons from the hot corona, leaving the UV emission from the accretion disk largely unaffected, thus resulting in significant X-ray weakness observed for type 1 QSOs. 3.…”

Section: X-ray Weakness Of Pso167-13mentioning

confidence: 99%

Chandra and Magellan/FIRE follow-up observations of PSO167-13: an X-ray weak QSO at $z=6.515$

Vito,

Brandt,

Ricci

et al. 2021

Preprint

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Context. The discovery of hundreds of quasi-stellar objects (QSOs) in the first Gyr of the Universe powered by already grown supermassive black holes (SMBHs) challenges our knowledge of SMBH formation. In particular, investigations of z > 6 QSOs presenting notable properties can provide unique information on the physics of fast SMBH growth in the early universe. Aims. We present the results of follow-up observations of the z = 6.515 radio-quiet QSO PSO167-13, which is interacting with a close companion galaxy. The PSO167-13 system has been recently proposed to host the first heavily obscured X-ray source at high redshift. The goals of these new observations are to confirm the existence of the X-ray source and to investigate the rest-frame UV properties of the QSO. Methods. We observed the PSO167-13 system with Chandra/ACIS-S (177 ks), and obtained new spectroscopic observations (7.2 h) with Magellan/FIRE. Results. No significant X-ray emission is detected from the PSO167-13 system, suggesting that the obscured X-ray source previously tentatively detected was either due to a strong background fluctuation or is highly variable. The upper limit (90% confidence level) on the X-ray emission of PSO167-13 (L 2−10 keV < 8.3 × 10 43 ergs −1 ) is the lowest available for a z > 6 QSO. The ratio between the X-ray and UV luminosity of α ox < −1.95 makes PSO167-13 a strong outlier from the α ox − L UV and L X − L bol relations. In particular, its X-ray emission is > 6 times weaker than the expectation based on its UV luminosity. The new Magellan/FIRE spectrum of PSO167-13 is strongly affected by the unfavorable sky conditions, but the tentatively detected C IV and Mg II emission lines appear strongly blueshifted. Conclusions. The most plausible explanations for the X-ray weakness of PSO167-13 are intrinsic weakness or small-scale absorption by Compton-thick material. The possible strong blueshift of its emission lines hints at the presence of nuclear winds, which could be related to its X-ray weakness.

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On the Observational Difference Between the Accretion Disk-Corona Connections among Super- and Sub-Eddington Accreting Active Galactic Nuclei

Cited by 3 publications

References 165 publications

The extreme properties of the nearby hyper-Eddington accreting Active Galactic Nucleus in IRAS 04416+1215

The extreme properties of the nearby hyper-Eddington accreting Active Galactic Nucleus in IRAS 04416+1215

What controls the UV-to-X-ray continuum shape in quasars?

Chandra and Magellan/FIRE follow-up observations of PSO167-13: an X-ray weak QSO at $z=6.515$

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