Changing Accretion Geometry of Seyfert 1 Mrk 335 with NuSTAR: A Comparative Study

Mondal, Santanu; Stalin, C. S.

doi:10.3390/galaxies9020021

Cited by 9 publications

(7 citation statements)

References 63 publications

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“…The current JeTCAF model is an updated version (including jet) of the TCAF model, which has been successfully applied to low-mass black hole X-ray binaries (Debnath et al 2014;Mondal et al 2014a;, and references therein) and to AGNs (e.g. Nandi et al 2019;Mondal & Stalin 2021) to fit their spectra and to infer the underlying accretion dynamics. In this model, the same corona, which is producing hard radiation, is also launching a jet at its base.…”

Section: Modellingmentioning

confidence: 99%

Variable mass accretion and failed wind explain changing-look phenomena in NGC 1365

Mondal

Adhikari

Hryniewicz

et al. 2022

A&A

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Changing-look active galactic nuclei (CLAGNs) show a complex nature in their X-ray spectral shape and line-of-sight column-density variation. The physical mechanisms responsible for these variations are unclear. Here, we study the spectral properties of a CLAGN, NGC 1365 using combined XMM-Newton and NuSTAR observations to understand the CL behavior. The model-fitted mass-accretion rate varied between 0.003 ± 0.001 and 0.009 ± 0.002 ṀEdd and the dynamic corona changed from 28 ± 3 to 10 ± 1 rg. We found that the variable absorption column density correlates with the mass accretion rate and the geometry of the corona. The derived wind velocity was sufficiently low compared to the escape velocity to drive the wind away from the disc for the epochs during which column densities were high. This suggests that the high and variable absorption can be due to failed winds from the disc. Our estimated ratio of mass outflow to inflow rate from the inner region of the disc lies between 0.019 ± 0.006 and 0.12 ± 0.04. From spectral fitting of the combined data, we found the mass of the central black hole to be constant 4.38 ± 0.34−4.51 ± 0.29 × 106 M⊙, consistent with earlier findings. The confidence contours of NH with other model parameters show that the model-fitted parameters are robust and non-degenerate. Our study construed that the changing accretion rate, which is a fundamental physical quantity and the geometry of the corona are driving the CL phenomena in NGC 1365. The physical picture considered in this work connects both variable continuum and variable absorbing medium scenarios.

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Section: Modellingmentioning

confidence: 99%

Variable mass accretion and failed wind explain changing-look phenomena in NGC 1365

Mondal

Adhikari

Hryniewicz

et al. 2022

A&A

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“…For spectral fitting, we ran the source code directly in XSPEC as a local model 6 . The Tcaf model 7 (Chakrabarti & Titarchuk 1995) can successfully fit the X-ray data on low-mass X-ray binaries (Debnath et al 2014(Debnath et al , 2015Mondal et al 2014;Iyer et al 2015, and references therein) and AGN (Mandal & Chakrabarti 2008;Nandi et al 2019;Mondal & Stalin 2021), and has been used to infer the outburst behaviour as well as the variability properties of compact objects. This model requires five parameters, namely, (i) the mass of the black hole (M BH ), (ii) the disc accretion rate ( ṁd ), (iii) the halo accretion rate ( ṁh ), (iv) the shock location, which is the boundary of the CENBOL (Chakrabarti 1989, X s in units of r s , where r s is the Schwarzschild radius, 2GM BH /c 2 ), and (v) the shock compression ratio (R).…”

Section: Spectral Analysismentioning

confidence: 99%

Flux and spectral variability of Mrk 421 during its moderate activity state usingNuSTAR: Possible accretion disc contribution?

Mondal

Rani

Stalin

et al. 2022

A&A

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Context. The X-ray emission in BL Lac objects is believed to be dominated by synchrotron emission from their relativistic jets. However, when the jet emission is not strong, one could expect signatures of X-ray emission from inverse Compton scattering of accretion disc photons by hot and energetic electrons in the corona. Moreover, the observed X-ray variability can also originate in the disc, and get propagated and amplified by the jet. Aims. Here, we present results on the BL Lac object Mrk 421 using the Nuclear Spectroscopic Telescope Array data acquired during 2017 when the source was in a moderate X-ray brightness state. For comparison with high jet activity state, we also considered one epoch of data in April 2013 when the source was in a very high X-ray brightness state. Our aim is to explore the possibility of the signature of accretion disc emission in the overall X-ray emission from Mrk 421 and also examine changes in accretion parameters considering their contribution to spectral variations. Methods. We divided each epoch of data into different segments in order to find small-scale variability. Data for all segments were fitted using a simple power-law model. We also fitted the full epoch data using the two component advective flow (TCAF) model to extract the accretion flow parameters. Furthermore, we estimated the X-ray flux coming from the different components of the flow using the lowest normalisation method and analysed the relations between them. For consistency, we performed the spectral analysis using models available in the literature. Results. The simple power-law function does not fit the spectra well, and a cutoff needs to be added. The spectral fitting of the data using the TCAF model shows that the data can be explained with a model where (a) the size of the dynamic corona at the base of the jet is from ∼28 to 10 rs, (b) the disc mass accretion rate is from 0.021 to 0.051 ṀEdd, (c) the halo mass accretion rate is from 0.22 to 0.35 ṀEdd, and (d) the viscosity parameter of the Keplerian accretion disc from 0.18 to 0.25. In the assumed model, the total flux, disc and jet flux correlate with the radio flux observed during these epochs. Conclusions. From the spectral analysis, we conclude that the spectra of all the epochs of Mrk 421 in 2017 are well described by the accretion-disc-based TCAF model. The estimated disc and jet flux relations with radio flux show that accretion disc can contribute to the observed X-ray emission, when X-ray data (that cover a small portion of the broad band spectral energy distribution of Mrk 421) are considered in isolation. However, the present disc-based models are disfavoured with respect to the relativistic jet models when considering the X-ray data in conjunction with data at other wavelengths.

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“…It harbors a supermassive black hole of M BH ≈ (1−3) × 10 7 M (see e.g., Kassebaum et al 1997;Peterson et al 1998Peterson et al , 2004Zu et al 2011;Grier et al 2012;Yao et al 2021, and references therein). This source has been extensively investigated in radio (Yang et al 2020;Yao et al 2021), infrared (Martínez-Paredes et al 2017), optical (Doroshenko et al 2005), X-rays (Parker et al 2014;Wilkins et al 2015;Mondal & Stalin 2021), and gamma rays (not detected, just upper limit established, see Kataoka et al 2011). The geometry and kinematics of the BLR in Mrk 335 have been investigated in Grier et al (2017).…”

Section: Application To Mrk 335mentioning

confidence: 99%

Nonthermal radiation from the central region of super-accreting active galactic nuclei

Checa

Romero

2022

A&A

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Context. The radio emission mechanism in active galactic nuclei (AGNs) with high accretion rates is unclear. It has been suggested that low-power jets may explain the observed radiation at subparsec scales. The mechanisms for jet formation at super-Eddington rates, however, are not well understood. On the same scale, clouds from the broad-line region (BLR) propagating with supersonic velocities in the wind launched by the accretion disk may lead to the production of nonthermal radiation. Aims. We aim to characterize the nonthermal emission produced by the propagation of clouds through the wind of the accretion disk in super-accreting AGNs, and to estimate the relevance of such a contribution to the radio band of the electromagnetic spectrum. Methods. We determined the conditions under which the BLR clouds are not destroyed by shocks or hydrodynamic instabilities when immersed in the powerful wind of the accretion disk. These clouds form bowshocks which are suitable sites for particle acceleration. We developed a semianalytical model to calculate the distribution of relativistic particles in these bowshocks and the associated spectral energy distribution (SED) of the emitted radiation. Results. For typical parameters of super-accreting AGNs, we find that the cloud-wind interactions can produce nonthermal emission from radio up to a few tens of TeV, with slight absorption effects, if the processes occur outside the wind photosphere. Conclusions. Radio emission in AGNs without jets can be explained if the accretion rate is super-Eddington and if there is a BLR at subparsec scales around the central black hole. The accretion rate must not be extremely high so most of the clouds orbit outside of the wind photosphere and the radiation can escape to the observer. Instabilities in the disk wind, which have previously been reported in numerical simulations, generate clumps that increase the filling factor of the overdensities in the BLR and enhance the emitted radiation.

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Changing Accretion Geometry of Seyfert 1 Mrk 335 with NuSTAR: A Comparative Study

Cited by 9 publications

References 63 publications

Variable mass accretion and failed wind explain changing-look phenomena in NGC 1365

Variable mass accretion and failed wind explain changing-look phenomena in NGC 1365

Flux and spectral variability of Mrk 421 during its moderate activity state usingNuSTAR: Possible accretion disc contribution?

Nonthermal radiation from the central region of super-accreting active galactic nuclei

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