NuSTAR view of Swift/BAT AGN: The R−Γ correlation

Panagiotou, Christos; Walter, R.

doi:10.1051/0004-6361/201937390

Cited by 27 publications

(30 citation statements)

References 42 publications

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“…1) rather than an NLS1 one, the latter of which is still commonly assumed in the literature. Moreover, no Compton hump is observed in the NuS-TAR spectra, which instead has a flat spectrum and a hard X-ray deficit above ∼30 keV; this is in line with what was found previously for the deep January 2017 NuSTAR observation, which caught the source in a slightly higher flux level (Panagiotou & Walter 2020;Ezhikode et al 2020).…”

Section: Summary and Discussionsupporting

confidence: 91%

“…The photon indices are found to be ∼1.7−1.8, confirming previous measurements found with the 2004 XMM-Newton (Boller et al 2007), the 2007 Suzaku (Patrick et al 2012;Walton et al 2013;Mantovani et al 2016;Waddell & Gallo 2020), and the 2017 NuSTAR (Ezhikode et al 2020;Panagiotou & Walter 2020) observations. Such values are much flatter than what are commonly observed in NLS1s but are consistent with BLS1s (e.g.…”

Section: Summary and Discussionsupporting

confidence: 85%

“…The spectral analysis above 3 keV allows us to characterise the hot corona and the relativistic reflection emission properties. The deep January 2017 NuSTAR observation was also included in the simultaneous fit (Ezhikode et al 2020;Panagiotou & Walter 2020). From the relxill reflection model, and assuming a primary exponential cutoff power-law continuum, we find moderate reflection strengths, R ∼ 0.1−0.2, and high cutoff energies, E cut ∼ 110−120 keV.…”

Section: Summary and Discussionmentioning

confidence: 94%

“…In this section we focus on the hard X-ray shape of Mrk 110 using the simultaneous XMM-Newton and NuSTAR data above 3 keV to prevent the fit from being driven by the soft X-ray emission. We also include here the deep NuSTAR observation of Mrk 110 performed in January 2017 (Ezhikode et al 2020;Panagiotou & Walter 2020).…”

Section: Spectral Analysis Above 3 Kev At Three Epochs: 2017 2019 and 2020mentioning

confidence: 99%

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

Porquet

Reeves

Grosso

et al. 2021

A&A

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Context. Soft and hard X-ray excesses, compared to the continuum power-law shape between ∼2−10 keV, are common features observed in the spectra of active galactic nuclei (AGN) and are associated with the accretion disc-corona system around the supermassive black hole. However, the dominant process at work is still highly debated and has been proposed to be either relativistic reflection or Comptonisation. Such an investigation can be problematic for AGN that have significant intrinsic absorption, either cold or warm, which can severely distort the observed continuum. Therefore, AGN with no (or very weak) intrinsic absorption along the line-of-sight, called bare AGN, are the best targets for directly probing disc-corona systems. Aims. We aim to characterise the main X-ray spectral physical components from the bright bare broad-line Seyfert 1 AGN Mrk 110, as well as the physical process(es) at work in its disc-corona system viewed almost face-on. Methods. We perform the X-ray broadband spectral analysis thanks to two simultaneous XMM-Newton and NuSTAR observations performed on November 16−17, 2019, and April 5−6, 2020. We also use a deep NuSTAR observation obtained in January 2017 for the spectral analysis above 3 keV. Results. The broadband X-ray spectra of Mrk 110 are characterised by the presence of a prominent and absorption-free smooth soft X-ray excess, moderately broad O VII and Fe Kα emission lines, and a lack of a strong Compton hump. The continuum above ∼3 keV is very similar at both epochs, while some variability (stronger when brighter) is present for the soft X-ray excess. A combination of soft and hard Comptonisation by a warm and hot corona, respectively, plus mildly relativistic disc reflection reproduce the broadband X-ray continuum very well. The inferred warm corona temperature, kTwarm ∼ 0.3 keV, is similar to the values found in other sub-Eddington AGN, whereas the hot corona temperature, kThot ∼ 21−31 keV (depending mainly on the assumed hot corona geometry), is found to be in the lower range of the values measured in AGN.

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Section: Summary and Discussionsupporting

confidence: 91%

Section: Summary and Discussionsupporting

confidence: 85%

Section: Summary and Discussionmentioning

confidence: 94%

Section: Spectral Analysis Above 3 Kev At Three Epochs: 2017 2019 and 2020mentioning

confidence: 99%

See 2 more Smart Citations

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

Porquet

Reeves

Grosso

et al. 2021

A&A

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“…The fraction of highly obscured AGNs is still poorly known. Hard X-ray observations indicates that only 10-15% of Seyfert 2s are Compton thick [5,6] (note that the fraction of sources sources with N > 10 26 cm −2 is almost unconstrained). The uncertainties on the CXB hard X-ray spectral shape and of its normalization is a major source of difficulty for the synthesis models and therefore for our knowledge of the accretion power in the Universe and of the importance of heavily obscured AGN in the Universe.…”

Section: Introductionmentioning

confidence: 99%

Measuring the Cosmic X-ray Background accurately

Li¹,

Produit²,

Walter³

2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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We propose a detector that attempts to measure the diffuse Cosmic X-ray Background (CXB) in the 10-100 keV energy band with unprecedented precision, so as to: 1). help to understand the source population of the CXB, most of which are proposed to be Active Galactic Nuclei (AGNs); 2). study the anisotropy of the CXB intensity over the sky, which helps to understand the largescale structure of the Universe. An obstacle of the above studies is the difficulty of measuring the absolute intensity of the CXB. Detectors working at X-ray bands suffer from time-dependent backgrounds which are difficult to subtract. Our design is similar to the projected MVN (Monitor Vsego Neba) Russian experiment, which mainly consist of four collimated spectrometers with a rotating obturator on top of the aperture. In this paper, we will show the construction ideas, its performance simulations, and some preliminary setup of the prototype, we will also discuss the launch opportunities.

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NuSTAR view of heavily absorbed AGN: The R–N_H correlation

Panagiotou

Walter

Paltani

2021

A&A

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Context. The nature of the putative torus and the outer geometry of active galactic nuclei (AGN) are still rather unknown and the subject of active research. Improving our understanding of them is crucial for developing a physical picture for the structure of AGN. Aims. The main goal of this work is to investigate the outer geometry of AGN by studying the observed hard X-ray spectrum of obscured sources. We primarily aim at researching the reflected emission in these sources. Methods. To that end, we analysed archived NuSTAR observations of a sample of nearby AGN, whose X-ray emission has been found to be heavily absorbed, with 1023 < NH < 2.5 × 1023 cm−2; the upper limit on NH was necessary due to the analysis we followed and the data quality. Fitting their emission with both a phenomelogical and a physical model, we investigated the relation between reflection and absorption. Results. The strength of reflected emission, as well as the equivalent width of the Fe Kα line, correlates with the absorption column density, which can be explained with a clumpy torus origin for the reflection in these sources. The shape of the observed correlation is found to be well reproduced when the effects of a clumpy torus with a variable filling factor are simulated. A similar increase in reflection seems to be featured even by sources with larger absorption, reaching the Compton thick (NH > 1.5 × 1024 cm−2) regime.

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NuSTAR view of Swift/BAT AGN: The R−Γ correlation

Cited by 27 publications

References 42 publications

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

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

Measuring the Cosmic X-ray Background accurately

NuSTAR view of heavily absorbed AGN: The R–N_H correlation

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NuSTAR view of Swift/BAT AGN: The R−Γ correlation

Cited by 27 publications

References 42 publications

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

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

Measuring the Cosmic X-ray Background accurately

NuSTAR view of heavily absorbed AGN: The R–NH correlation

Contact Info

Product

Resources

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NuSTAR view of heavily absorbed AGN: The R–N_H correlation