A Deep X-Ray View of the Bare Agn Ark 120. I. Revealing the Soft X-Ray Line Emission

Reeves, J. N.; Porquet, D.; Braito, V.; Nardini, E.; Lobban, A.; Turner, T. J.

doi:10.3847/0004-637x/828/2/98

Cited by 26 publications

(29 citation statements)

References 86 publications

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“…3.1. Building the model ThebareSeyfertgalaxyArk120(z = 0.0327Osterbrock & Phillips 1977) is an excellent source for studying the accretion disc-corona environment, since no significant extra-Galactic absorption along the line of sight is present, both in the UV and in X-rays (Crenshaw et al 1999;Vaughan et al 2004;Reeves et al 2016).…”

Section: Discussionmentioning

confidence: 99%

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A deep X-ray view of the bare AGN Ark 120

Marinucci

Porquet

Tamborra

et al. 2019

A&A

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Context. The spectral shape of the hard X-ray continuum of Active Galactic Nuclei (AGN) can be ascribed to inverse Compton scattering of optical/UV seed photons from the accretion disc by a hot corona of electrons. This physical process produces a polarization signal which is strongly sensitive to the geometry of the scattering medium (i.e. the hot corona) and of the radiation field. Aims. MoCA (Monte Carlo code for Comptonisation in Astrophysics) is a versatile code which allows for different geometries and configurations to be tested for Compton scattering in compact objects. A single photon approach is considered as well as polarisation and Klein–Nishina effects. In this work, we selected four different geometries for the scattering electrons cloud above the accretion disc, namely an extended slab, an extended spheroid and two compact spheroids. Methods. We discuss the first application of the MoCA model to reproduce the hard X-ray primary continuum of the bare Seyfert 1 galaxy Ark 120, using different geometries for the hot corona above the accretion disc. The lack of extra-Galactic absorption along the line of sight makes it an excellent target for studying the accretion disc-corona system. We report on the spectral analysis of the simultaneous 2013 and 2014 XMM-Newton and NuSTAR observations of the source. Results. A general agreement is found between the best fit values of the hot coronal parameters obtained with MoCA and the ones inferred using other Comptonisation codes from the literature. The expected polarization signal from the best fits with MoCA is then presented and discussed, in view of the launch in 2021 of the Imaging X-ray Polarimetry Explorer (IXPE). Conclusions. We find that none of the tested geometries for the hot corona (extended slab and extended/compact spheroids) can be statistically preferred, based on spectroscopy solely. In the future, an IXPE observation less than 1 Ms long will clearly distinguish between an extended slab or a spherical hot corona.

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Section: Discussionmentioning

confidence: 99%

“…See text for details about the four models applied. The only residuals present are near to 0.5 keV, which are likely associated to the OI K-shell absorption from our galaxy (seeReeves et al 2016, for further details).…”

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confidence: 91%

A deep X-ray view of the bare AGN Ark 120

Marinucci

Porquet

Tamborra

et al. 2019

A&A

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“…619-48,834 1991-1992 20 5.0 × 10.0 0.70 1.078 ± 0.005 0.46 ± 0.06 D08 5 48, 629-53,445 1992-2005 88 3.0 × 11.0 1.13 1.037 ± 0.003 0.09 ± 0.03 L 6 57,295-57,839 2015-2017 100 2.5 × 8.5 0.96 · · · · · · Photometry b M79 c 7 25, 622-33,446 1935-1950 52 · · · · · · · · · · · · P83 8 42, 392-44,226 1974-1979 36 15.0 · · · 0.687 ± 0.087 0.45 ± 0.95 P89 2 43, 426-47,414 1977-1988 In this paper, we study the variability and analyze the possible periodicity in Ark 120 (z = 0.03271 1 ), a nearby radioquiet AGN with a radio-loudness R ≈ 0.1 (Condon et al 1998;Ho 2002). Ark 120 has been intensively observed and investigated in optical/UV (e.g., Kollatschny et al 1981a,b;Schulz & Rafanelli 1981;Alloin et al 1988;Marziani et al 1992;Peterson et al 1998;Stanic et al 2000;Popović et al 2001;Doroshenko et al 2008;Kuehn et al 2008) and X-ray bands (e.g., Vaughan et al 2004;Nardini et al 2016;Reeves et al 2016;Gliozzi et al 2017;Lobban et al 2018). The published photometric and spectroscopic monitoring data of 1 The redshift is taken from the NASA/IPAC Extragalactic Database, corresponding to a luminosity distance of 143 Mpc based on the WMAP-5 cosmological parameters H 0 = 70.5 km s −1 Mpc −1 , Ωm = 0.27, and Ω Λ = 0.73.…”

Section: Introductionmentioning

confidence: 99%

A Possible ∼20 yr Periodicity in Long-term Optical Photometric and Spectral Variations of the Nearby Radio-quiet Active Galactic Nucleus Ark 120

Wang

Zhang

et al. 2019

ApJS

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We study the long-term variability in the optical monitoring database of Ark 120, a nearby radio-quiet active galactic nucleus (AGN) at a distance of 143 Mpc (z = 0.03271). We compiled the historical archival photometric and spectroscopic data since 1974 and conducted a new two-year monitoring campaign in 2015-2017, resulting in a total temporal baseline over four decades. The long-term variations in the optical continuum exhibit a wave-like pattern and the Hβ integrated flux series varies with a similar behaviour. The broad Hβ profiles have asymmetric double peaks, which change strongly with time and tend to merge into a single peak during some epochs. The period in the optical continuum determined from various period-search methods is about 20 years and the estimated false alarm probability with null hypothesis simulations is about 1 × 10 −3 . The overall variations of the broad Hβ profiles also follow the same period. However, the present database only covers two cycles of the suggested period, which strongly encourages continued monitoring to track more cycles and confirm the periodicity. Nevertheless, in light of the possible periodicity and the complicated Hβ profile, Ark 120 is one candidate of the nearest radio-quiet AGNs with possible periodic variability and it is thereby a potential candidate host for a sub-parsec supermassive black hole binary. (15) the All-Sky Automated Survey for Supernovae database (Shappee et al. 2014; Kochanek et al. 2017). a The flux of [O III] λ5007 used for absolute calibration of spectra in the dataset. b The photometric data of all the datasets are at V -band, except for dataset M79 at B-band.c This dataset has no temporal overlap with the other datasets so that it is impossible to do intercalibration. We simply adjust the fluxes to make the mean and standard deviation to be at the same scales as those of the other datasets. We do not use this dataset for periodicity analysis.d This dataset includes 15 additional observations (50,863-52,282) that have not been public.e There is a large flux difference with respect to the other datasets. We offset the fluxes by −20.0 × 10 −15 erg s −1 cm −2 Å −1 before performing intercalibration.f This dataset has a poor temporal overlap with the other datasets and we simply fix ϕ = 1.

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“…These measurements of L may be compared with those derived using other methods, to determine the reliability of the latter and the assumptions made. Indeed, in principle the enhancement effect could provide a very powerful diagnostic tool for determining plasma pathlengths in any remote, spatially-unresolved, astrophysical source which shows similar values of N e and L to the late-type stellar cases, such as the coronal regions of active galactic nuclei (Reeves et al 2016). …”

Section: Resultsmentioning

confidence: 99%

X-ray line coincidence photopumping in a solar flare

Keenan

Poppenhaeger

Mathioudakis

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Line coincidence photopumping is a process where the electrons of an atomic or molecular species are radiatively excited through the absorption of line emission from another species at a coincident wavelength. There are many instances of line coincidence photopumping in astrophysical sources at optical and ultraviolet wavelengths, with the most famous example being Bowen fluorescence (pumping of O iii 303.80Å by He ii), but none to our knowledge in X-rays. However, here we report on a scheme where a He-like line of Ne ix at 11.000Å is photopumped by He-like Na x at 11.003Å, which predicts significant intensity enhancement in the Ne ix 82.76Å transition under physical conditions found in solar flare plasmas. A comparison of our theoretical models with published X-ray observations of a solar flare obtained during a rocket flight provides evidence for line enhancement, with the measured degree of enhancement being consistent with that expected from theory, a truly surprising result. Observations of this enhancement during flares on stars other than the Sun would provide a powerful new diagnostic tool for determining the sizes of flare loops in these distant, spatially-unresolved, astronomical sources.

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A Deep X-Ray View of the Bare Agn Ark 120. I. Revealing the Soft X-Ray Line Emission

Cited by 26 publications

References 86 publications

A deep X-ray view of the bare AGN Ark 120

A deep X-ray view of the bare AGN Ark 120

A Possible ∼20 yr Periodicity in Long-term Optical Photometric and Spectral Variations of the Nearby Radio-quiet Active Galactic Nucleus Ark 120

X-ray line coincidence photopumping in a solar flare

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