Fe Kα Research Articles

Timing and spectral variability of the high-mass X-ray pulsar GX 301−2 over orbital phases observed by Insight-HXMT

ABSTRACT We report the orbital X-ray variability of the high-mass X-ray binary (HMXB) GX 301−2. GX 301−2 underwent a spin-up process in 2018–2020 with the period evolving from ∼685–670 s. The energy-resolved pulse profiles of the pulsar at 1–60 keV varied from single-peaked and sinusoidal shapes to multipeaked ones across different orbital phases. Pulse fractions evolving over the orbit had negative correlations with the X-ray flux. The broad-band X-ray energy spectrum of the pulsar can be described with a partially covered negative–positive cut-off power-law continuum model. Near the periastron passage of the pulsar we found strong variation in the additional column density ($N_{\mathrm{H}_{2}}$), which correlated with variation of the flux. Curves of growth for both Fe Kα and Fe Kβ lines were plotted to investigate the distribution of matter around the neutron star. We also found evidence for two cyclotron absorption lines in the phase-averaged spectra in GX 301−2, with one line of 30–42 keV and the other line varying over 48–56 keV. The centroid energies of both lines show a similar relationship with X-ray luminosity: positive correlation in the lower luminosity range, and a negative relation above a critical luminosity of $10^{37}\, \rm erg\, s^{-1}$. We estimate the surface magnetic field of the neutron star in GX 301−2 to be ∼(0.5–2) × 1013 G. The two cyclotron line energies have a nearly fixed ratio of ∼1.63 while having a low strength ratio (∼0.05), suggesting that these two features may actually be one line.

NuSTAR Observation of LS 5039

Abstract LS 5039 is a high-mass γ-ray binary hosting a compact object of unknown type. NuSTAR observed LS 5039 during the entire 3.9-day binary period. We performed a periodic signal search up to 1000 Hz, which did not produce credible period candidates. We do see the 9.05 s period candidate, originally reported by Yoneda et al. using the same data, in the Fourier power spectrum, but we find that the statistical significance of this feature is too low to claim it as a real detection. We did not find significant bursts or quasiperiodic variability either. The modulation with orbital period is clearly seen and remains unchanged over a timescale of 10 years when compared to the earlier Suzaku light curve. The joint analysis of the NuSTAR and Suzaku XIS data shows that the 0.7–70 keV spectrum can be satisfactory described by a single absorbed power-law model with no evidence of a cutoff at higher energies. The slope of the spectrum is anticorrelated with the flux during the binary orbit. If LS 5039 hosts a young neutron star, its X-ray pulsations therefore appear to be outshone by the intrabinary shock emission. The lack of spectral lines and/or an exponential cutoff at higher energies suggests that the putative neutron star is not actively accreting. Although a black hole scenario still remains a possibility, the lack of variability or Fe Kα lines, which typically accompany accretion, makes it less likely.

Evidence for Fe Kα line and soft X-ray lag in NGC 7456 ultraluminous X-ray source-1

ABSTRACT We report the first detection of an Fe Kα line and soft X-ray lag in the ultraluminous X-ray (ULX) source NGC 7456 ULX-1. The XMM–Newton spectra show the presence of the 6.4 keV Fe line at 2.6σ confidence and an upper limit on the FWHM of 32900 km s−1. Assuming that the line arises by reflection from a Keplerian disk, it must originate beyond 85rg from the compact object. As a result of Fourier timing analysis, we found that the soft X-ray photons lag behind the hard X-ray photons with a ∼1300 s delay. The covariance spectra indicate that the hard spectral component is responsible for the correlated variability and the soft X-ray lag. This is the second ULX in which an Fe Kα line is found, the fifth with a soft X-ray lag, and the first with both features detected.

Chandra Observations of Excess Fe Kα Line Emission in Galaxies with High Star Formation Rates: X-Ray Reflection on Galaxy Scales?

Abstract In active galactic nuclei (AGNs), fluorescent Fe Kα (iron) line emission is generally interpreted as originating from obscuring material around a supermassive black hole on the scale of a few parsecs. However, recent Chandra studies indicate the existence of iron line emission extending to kiloparsec scales in the host galaxy. The connection between iron line emission and large-scale material can be spatially resolved directly only in nearby galaxies, but could be inferred in more distant AGNs by a connection between line emission and star-forming gas and dust that is more extended than the parsec-scale torus. Here we present the results from a stacking analysis and X-ray spectral fitting performed on sources in the Chandra Deep Field South (CDFS) 7 Ms observations. From the deep stacked spectra, we select sources with stellar mass at 0.5 < z < 2, obtaining 25 sources with high-infrared (IR) luminosity (star formation rate, SFRFIR ≥ 17 M ☉ yr−1) and 32 sources below this threshold. We find that the equivalent width (EW) of the iron line EW(Fe) is a factor of three higher with 3σ significance for high-IR luminosity measured from Herschel observations, indicating a connection between iron line emission and star-forming material on galaxy scales. We show that there is no significant dependence of the EW(Fe) on M * or X-ray luminosity, suggesting that the reflection of AGN X-ray emission over large scales in their host galaxies may be widespread.

Accretion properties of MAXI J1813-095 during its failed outburst in 2018

We present the results obtained from detailed timing and spectral studies of a black hole candidate MAXI J1813–095 using Swift, NICER, and NuSTAR observations during its 2018 outburst. The timing behavior of the source is mainly studied by examining NICER light curves in the 0.5–10 keV range. We did not find any signature of quasi-periodic oscillations in the power density spectra of the source. We carry out spectral analysis with a combined disk blackbody & power law model, and physical two-component advective flow (TCAF) model. From the combined disk blackbody & power-law model, we extracted thermal and non-thermal fluxes, photon index and inner disk temperature. We also find evidence for weak reflection in the spectra. We have tested the physical TCAF model on a broadband spectrum from NuSTAR and Swift/XRT. The parameters like mass accretion rates, the size of Compton clouds and the shock strength are extracted. Our result affirms that the source remained in the hard state during the entire outburst which indicates a ‘failed’ outburst. We estimate the mass of the black hole as 7.4 ± 1.5 M ⊙ from the spectral study with the TCAF model. We apply the LAOR model for the Fe Kα line emission. From this, the spin parameter of the black hole is ascertained as a* > 0.76$ The inclination angle of the system is estimated to be in the range of 28° – 45° from the reflection model. We find the source distance to be ∼ 6 kpc.

A Reaction–Diffusion–Reaction System for Forming Periodic Precipitation Bands of Cu-Fe-Based Prussian Blue Analogues

We propose a simple and novel system to form precipitation patterns of Cu-Fe-based Prussian blue analogues (Cu-Fe PBA) in agarose gel through coupled electrochemical reactions, reactant ion diffusion influenced by electric field, and precipitation reactions. The spatiotemporal evolution, spatial distribution, and crystallite morphologies of the precipitates were investigated by visual inspection, Fe Kα intensity distribution measurements, and optical and scanning electron microscope observations. The observed precipitation patterns and their evolution depended on the applied voltage. Multicolored periodic precipitation bands were stochastically formed under cyclic alternating voltage (4 V for 1 h and then 1 V for 4 h per cycle). The distances between adjacent bands were randomly distributed (0.30 ± 0.25 mm). The sizes and shapes of the crystallites generated in the gel were position-dependent. Cubic but fairly irregular crystallites (0.1–0.8 μm) were formed in the periodic bands, whereas definitely cube-shaped crystallites (1–3 μm) appeared close to the anode. These cube-like reddish–brown crystallites were assigned to Cu-FeII PBA. In some periodic bands, plate-like blue crystallites (assigned to Cu(OH)2) were also present. Future issues for potential applications of the observed periodic banding for selective preparation of Cu-Fe PBA crystallites were discussed.

X-Ray Constraint on the Location of the AGN Torus in the Circinus Galaxy

Abstract The location of the obscuring “torus” in an active galactic nucleus (AGN) is still an unresolved issue. The line widths of X-ray fluorescence lines originating from the torus, particularly Fe Kα, carry key information on the radii of line-emitting regions. Utilizing XCLUMPY, an X-ray clumpy torus model, we develop a realistic model of emission line profiles from an AGN torus where we take into account line broadening due to the Keplerian motion around the black hole. Then, we apply the updated model to the best available broadband spectra (3–100 keV) of the Circinus galaxy observed with Suzaku, XMM-Newton, Nuclear Spectroscopic Telescope Array, and Chandra, including 0.62 Ms Chandra/HETG data. We confirm that the torus is Compton-thick (hydrogen column density along the equatorial plane is ), geometrically thin (torus angular width ), viewed edge-on (inclination ), and has supersolar abundance ( times solar). Simultaneously analyzing the Chandra/HETG first-, second-, and third-order spectra with consideration of the spatial extent of the Fe Kα line-emitting region, we constrain the inner radius of the torus to be times the gravitational radius, or for a black hole mass of (1.7 ± 0.3) × 106 M ⊙. This is about three times smaller than that estimated from the dust sublimation radius, suggesting that the inner side of the dusty region of the torus is composed of dust-free gas.

Exploring higher order images with Fe Kα-lines from relativistic discs: black hole spin determination and bias

ABSTRACT We study the contributions to the relativistic Fe K α line profile from higher order images (HOIs) produced by strongly deflected rays from the disc which cross the plunging region, located between the innermost stable circular orbit (ISCO) radius and the event horizon of a Kerr black hole. We investigate the characteristics features imprinted by the HOIs in the line profile for different black hole spins, disc emissivity laws, and inclinations. We find that they extend from the red wing of the profile up to energies slightly lower than those of the blue peak, adding ∼0.4–1.3 per cent to the total line flux. The contribution to the specific flux is often in the ∼1 to 7 per cent range, with the highest values attained for low and negative spin (a ≲ 0.3) black holes surrounded by intermediate inclination angle (i ∼ 40°) discs. We simulate future observations of a black hole X-ray binary system with the Large Area Detector of the planned X-ray astronomy enhanced X-ray Timing and Polarimetry Mission (eXTP) and find that the Fe Kα line profiles of systems accreting at ≲1 per cent the Eddington rate are affected by the HOI features for a range of parameters. This would provide evidence of the extreme gravitational lensing of HOI rays. Our simulations show also that not accounting for HOI contributions to the Fe Kα line profile may systematically bias measurements of the black hole spin parameter towards values higher by up to ∼0.3 than the inputted ones.

Properties of Faint X-ray Activity of XTE J1908+094 in 2019

We study the properties of the faint X-ray activity of Galactic transient black hole candidate XTE J1908+094 during its 2019 outburst. Here, we report the results of detailed spectral and temporal analysis during this outburst using observations from Nuclear Spectroscopic Telescope Array (NuSTAR). We have not observed any quasi-periodic-oscillations (QPOs) in the power density spectrum (PDS). The spectral study suggests that the source remained in the softer (more precisely, in the soft–intermediate) spectral state during this short period of X-ray activity. We notice a faint but broad Fe Kα emission line at around 6.5 keV. We also estimate the probable mass of the black hole to be 6.5−0.7+0.5M⊙, with 90% confidence.

Looking through the photoionisation wake: Vela X−1 at φorb ≈ 0.75 with Chandra/HETG

Context. The supergiant X-ray binary Vela X−1 represents one of the best astrophysical sources to investigate the wind environment of an O/B star irradiated by an accreting neutron star. Previous studies and hydrodynamic simulations of the system have revealed a clumpy environment and the presence of two wakes: an accretion wake surrounding the compact object and a photoionisation wake trailing it along the orbit. Aims. Our goal is to conduct, for the first time, high-resolution spectroscopy on Chandra/HETGS data at the orbital phase φorb ≈ 0.75, when the line of sight is crossing the photoionisation wake. We aim to conduct plasma diagnostics, inferring the structure and the geometry of the wind. Methods. We performed a blind search employing a Bayesian block algorithm to find discrete spectral features and identify them thanks to the most recent laboratory results or through atomic databases. Plasma properties were inferred both with empirical techniques and with photoionisation models within CLOUDY and SPEX. Results. We detect and identify five narrow radiative recombination continua (Mg XI-XII, Ne IX-X, O VIII) and several emission lines from Fe, S, Si, Mg, Ne, Al, and Na, including four He-like triplets (S XV, Si XIII, Mg XI, and Ne IX). Photoionisation models reproduce the overall spectrum well, except for the near-neutral fluorescence lines of Fe, S, and Si. Conclusions. We conclude that the plasma is mainly photoionised, but more than one component is most likely present, which is consistent with a multi-phase plasma scenario, where denser and colder clumps of matter are embedded in the hot, photoionised wind of the companion star. Simulations with the future X-ray satellites Athena and XRISM show that a few hundred seconds of exposure is sufficient to disentangle the lines of the Fe Kα doublet and the He-like Fe XXV, improving, in general, the determination of the plasma parameters.

Stellar wind structures in the eclipsing binary system IGR J18027–2016

Context. IGR J18027–2016 is an obscured high-mass X-ray binary formed by a neutron star accreting from the wind of a supergiant companion with a ∼4.57 d orbital period. The source shows an asymmetric eclipse profile that remained stable across several years. Aims. We aim to investigate the geometrical and physical properties of stellar wind structures formed by the interaction between the compact object and the supergiant star. Methods. In this work we analysed the temporal and spectral evolution of this source along its orbit using six archival XMM-Newton observations and the accumulated Swift/BAT hard X-ray light curve. Results. The XMM-Newton light curves show that the source hardens during the ingress and egress of the eclipse, in accordance with the asymmetric profile seen in Swift/BAT data. A reduced pulse modulation is observed on the ingress to the eclipse. We modelled XMM-Newton spectra by means of a thermally Comptonized continuum (NTHCOMP), adding two Gaussian emission lines corresponding to Fe Kα and Fe Kβ. We included two absorption components to account for the interstellar and intrinsic media. We found that the local absorption column outside the eclipse fluctuates uniformly around ∼6 × 1022 cm−2, whereas when the source enters and leaves the eclipse the column increases by a factor of ≳3, reaching values up to ∼35 and ∼15 × 1022 cm−2, respectively. Conclusions. Combining the physical properties derived from the spectral analysis, we propose a scenario in which, primarily, a photo-ionisation wake and, secondarily, an accretion wake are responsible for the orbital evolution of the absorption column, continuum emission, and variability seen at the Fe-line complex.

Relativistic Reflection in NGC 4151

Abstract We investigate the X-ray spectrum of the Seyfert galaxy NGC 4151 using the simultaneous Suzaku/NuSTAR observation and flux-resolved INTEGRAL spectra supplemented by Suzaku and XMM observations. Our best spectral solution indicates that the narrow Fe Kα line is produced in Compton-thin matter at a distance of several hundred gravitational radii. In such a model, we find a weak but significant relativistic reflection from a disk truncated at about 10 gravitational radii when the source is in bright X-ray states. We do not find evidence either for or against the presence of relativistic reflection in the dim X-ray state. We also rule out models with X-ray emission dominated by a source located very close to the black hole horizon, which was proposed in previous works implementing the lamppost geometry for this source. We point out that accurate computation of the thermal Comptonization spectrum and its distortion by strong gravity is crucial in applications of the lamppost geometry to the NuSTAR data.

The Kiloparsec-scale Fe Ka Emission in the Compton-thin Seyfert 2 Galaxy NGC 4388 Resolved by Chandra

Abstract We present imaging and spectral analysis of the combined ∼48 ks Chandra observations of Seyfert 2 galaxy NGC 4388. Compared with previous studies, three prominent extended X-ray structures around the nucleus on a kiloparsec-scale are well imaged, allowing an in-depth spatially resolved study. Both the extended hard continuum (4–6 keV) and the Fe Kα line (6.2–6.7 keV) show similar morphology, consistent with a scenario where the ionizing emission from the nucleus is reprocessed by circumnuclear cold gas, resulting in a weak reflection continuum and an associated neutral Fe Kα line. This has been seen in other Compton-thick active galactic nuclei (AGN), but NGC 4388 is one of the rare cases with a lower column density (N H < 1.25 × 1024 cm−2) along the line of sight. Significant differences in equivalent width of the Fe Kα emission line (up to a factor of 3) are found for the nuclear and extended regions. Such a difference could be ascribed to different column densities or scattering angles with respect to the line of sight, rather than variations in iron abundances. The northeast and west extended structures appear to be aligned with the larger-scale galactic disk and dust lane in the HST V − H color map, and are located at the peak of molecular gas distribution. The morphology of remaining extended features likely traces edges of a known radio jet, indicating that the outflow at the kiloparsec-scale may have compressed the interstellar gas and produced clumps working as the reflector to enhance line emission. In addition, using [O iv] emission as a proxy of the AGN intrinsic luminosity, we find that both of the extended Fe Kα emission and reflection continuum are linearly correlated with the [O iv] luminosity, which indicates a connection between the central AGN and the extended emission.

X-ray reprocessing in accreting pulsar GX 301-2 observed with Insight-HXMT

ABSTRACT We investigate the absorption and emission features in observations of GX 301-2 detected with Insight-HXMT/LE in 2017–2019. At different orbital phases, we found prominent Fe Kα, Kβ, and Ni Kα lines, as well as Compton shoulders and Fe K-shell absorption edges. These features are due to the X-ray reprocessing caused by the interaction between the radiation from the source and surrounding accretion material. According to the ratio of iron lines (Kα and Kβ), we infer the accretion material is in a low ionization state. We find an orbital-dependent local absorption column density, which has a large value and strong variability around the periastron. We explain its variability as a result of inhomogeneities of the accretion environment and/or instabilities of accretion processes. In addition, the variable local column density is correlated with the equivalent width of the iron Kα lines throughout the orbit, which suggests that the accretion material near the neutron star is spherically distributed.

Einstein’s Geometrical versus Feynman’s Quantum-Field Approaches to Gravity Physics: Testing by Modern Multimessenger Astronomy

Modern multimessenger astronomy delivers unique opportunity for performing crucial observations that allow for testing the physics of the gravitational interaction. These tests include detection of gravitational waves by advanced LIGO-Virgo antennas, Event Horizon Telescope observations of central relativistic compact objects (RCO) in active galactic nuclei (AGN), X-ray spectroscopic observations of Fe Kα line in AGN, Galactic X-ray sources measurement of masses and radiuses of neutron stars, quark stars, and other RCO. A very important task of observational cosmology is to perform large surveys of galactic distances independent on cosmological redshifts for testing the nature of the Hubble law and peculiar velocities. Forthcoming multimessenger astronomy, while using such facilities as advanced LIGO-Virgo, Event Horizon Telescope (EHT), ALMA, WALLABY, JWST, EUCLID, and THESEUS, can elucidate the relation between Einstein’s geometrical and Feynman’s quantum-field approaches to gravity physics and deliver a new possibilities for unification of gravitation with other fundamental quantum physical interactions.

The chemical composition of the accretion disc and donor star in ultra-compact X-ray binaries: A comprehensive X-ray analysis

ABSTRACT We have analysed the X-ray spectra of all known Ultra-Compact X-ray Binaries (UCXBs), with the purpose of constraining the chemical composition of their accretion disc and donor star. Our investigation was focused on the presence (or absence) of the Fe Kα emission line, which was used as the probe of chemical composition of the disc, based on previously established theoretical predictions for the reflection of X-ray radiation off the surface of C/O-rich or He-rich accretion discs in UCXBs. We have contrasted the results of our spectral analysis to the history of type I X-ray bursts from these systems, which can also indicate donor star composition. We found that UCXBs with prominent and persistent iron Kα emission also featured repeat bursting activity. On the other hand, the UCXBs for which no iron line was detected, appear to have few or no type I X-ray bursts detected over more than a decade of monitoring. Based on Monte Carlo simulations, demonstrating a strong correlation between the Fe Kα line strength and the abundance of C and O in the accretion disc material and given the expected correlation between the H/He abundance and the recurrence rate of type I X-ray bursts, we propose that there is a considerable likelihood that UCXBs with persistent iron emission have He-rich donors, while those that do not, likely have C/O or O/Ne/Mg-rich donors. Our result strongly advocate for the development of more sophisticated simulations of X-ray reflection from hydrogen-poor accretion discs.

Probing the nuclear and circumnuclear properties of NGC 6300 using X-ray observations

ABSTRACT We present the results obtained from a detailed X-ray timing and spectral analysis of the Seyfert 2 galaxy NGC 6300 by using observations from the Suzaku observatory, theChandra X-ray Observatory and the Nuclear Spectroscopic Telescope Array(NuSTAR) mission between 2007 and 2016. We calculate the variance and the rms fractional variability of the source in different energy bands and we find variabilities in various energy bands. Spectral properties of the source are studied by using various phenomenological and physical models. The properties of the Compton clouds, reflection, Fe Kα line emission and soft X-ray excess are studied in detail. Several physical parameters of the source are extracted and investigated to establish the presence/absence of any correlation between them. We also investigate the nature of the circumnuclear ‘torus’ and we find that the torus is not uniform, but clumpy. The observed changes in the line-of-sight column density can be explained in terms of transiting clouds. The iron line-emitting region is found to be different in the different epochs of observations. We also observe that the torus and the nucleus independently evolve over the years.

Canonical X-Ray Fluorescence Line Intensities as Column Density Indicators

Abstract X-ray line fluorescence is ubiquitous around powerful accretion sources, namely, active galactic nuclei and X-ray binaries. The brightest and best-studied line is the Fe Kα line at λ = 1.937 Å(6.4 keV). This paper presents a survey of all well-measured Chandra/HETG grating spectra featuring several Kα fluorescence lines from elements between Mg and Ni. Despite the variety of sources and physical conditions, we identify a common trend that dictates the Kα line intensity ratios between elements. For the most part, the line intensities are well described by a simple, plane-parallel approximation of a near-neutral, solar-abundance, high column density (N H > 1024 cm−2) medium. This approximation gives canonical photon-intensity line ratios for the Kα fluorescence of all elements, e.g., 0.104:0.069:1.0:0.043 for Si:S:Fe:Ni, respectively. Deviations from these ratios are shown to be primarily due to excess column density along the line of sight beyond the Galactic column. Therefore, measured fluorescence line ratios provide an independent estimate of N H and insight into the environment of accretion sources. Residual discrepancies with the canonical ratios could be due to a variety of effects such as a fluorescing medium with N H < 1024 cm−2, a non-neutral medium, variations in the illuminating spectrum, nonsolar abundances, or an irregular source geometry. However, evidently and perhaps surprisingly, these are uncommon, and their effect remains minor.

Unveiling Sub-pc Supermassive Black Hole Binary Candidates in Active Galactic Nuclei

Abstract The elusive supermassive black hole binaries (SMBHBs) are thought to be the penultimate stage of galaxy mergers, preceding a final coalescence phase. SMBHBs are sources of continuous gravitational waves, possibly detectable by pulsar timing arrays; the identification of candidates could help in performing targeted gravitational wave searches. Due to SMBHBs’ origin in the innermost parts of active galactic nuclei (AGN), X-rays are a promising tool for unveiling their presence, by means of either double Fe Kα emission lines or periodicity in their light curve. Here we report on a new method for selecting SMBHBs by means of the presence of a periodic signal in their Swift Burst Alert Telescope (BAT) 105 month light curves. Our technique is based on Fisher’s exact g-test and takes into account the possible presence of colored noise. Among the 553 AGN selected for our investigation, only the Seyfert 1.5 galaxy Mrk 915 emerges as a candidate SMBHB; from subsequent analysis of its light curve we find a period P 0 = 35 ± 2 months, and the null hypothesis is rejected at the 3.7σ confidence level. We also present a detailed analysis of the BAT light curve of the only previously X-ray-selected binary candidate source in the literature, the Seyfert 2 galaxy MCG+11-11-032. We find P 0 = 26.3 ± 0.6 months, consistent with the one inferred from previously reported double Fe Kα emission lines.

Isolated AGNs NGC 5347, ESO 438‐009, MCG‐02‐04‐090, and J11366‐6002: Swift and NuSTAR joined view1

AbstractWe present the spectral analysis with the Nuclear Spectroscopic Telescope Array (NuSTAR) of four isolated galaxies with active galactic nuclei selected from the 2MIG catalogue: NGC 5347, ESO 438‐009, MCG‐02‐09‐040, and IGR J11366‐6002. We also used the Swift/Burst Alert Telescope (BAT) data up to ∼150 keV for MCG 02‐09‐040, ESO 438‐009, and IGR J11366‐6002 as well as the Swift/XRT data in 0.3–10 keV energy band for NGC 5347, ESO 438‐009, and IGR J11366‐6002. All the sources appear to have the reflected spectrum component with different reflection fractions in addition to the primary power‐law continuum. We found that power‐law indices for these sources lie between 1.6 and 1.8. The spectra of two sources, NGC 5347 and MCG‐02‐09‐040, show the Fe Kα emission line. For both of these sources, the Fe Kα lines have a significant value of EW ∼1 keV. The X‐ray spectrum of NGC 5347 is best fitted by a pure reflection model with Ecut ∼ 117 keV and without the presence of any additional primary power‐law component. We also found that the X‐ray spectrum of MCG‐02‐09‐040 shows the presence of heavy neutral obscuration of NH ∼ 1024 cm−2. However, this provides a non‐physical value of reflection in the case with fitting by a simple reflection model. A more appropriate fit is obtained with adopting the physical Monte Carlo‐based model as BNTorus. It allowed us to determine the absorption value of NH ∼ 1.04 × 1024 cm−2 and reasonable power‐law index of Γ ≈ 1.63. Results for MCG‐02‐09‐040 are presented for the first time.