We present the long-term X-ray spectral and temporal analysis of a 'bare-type AGN' Ark 120. We consider the observations from XMM-Newton, Suzaku, Swift, and NuSTAR from 2003 to 2018. The spectral properties of this source are studied using various phenomenological and physical models present in the literature. We report (a) the variations of several physical parameters, such as the temperature and optical depth of the electron cloud, the size of the Compton cloud, and accretion rate for the last fifteen years. The spectral variations are explained from the change in the accretion dynamics; (b) the X-ray time delay between 0.2-2 keV and 3-10 keV light-curves exhibited zero-delay in 2003, positive delay of 4.71 \pm 2.1 ks in 2013, and negative delay of 4.15 \pm 1.5 ks in 2014. The delays are explained considering Comptonization, reflection, and light-crossing time; (c) the long term intrinsic luminosities obtained using nthcomp, of the soft-excess and the primary continuum show a correlation with a Pearson Correlation Coefficient of 0.922. This indicates that the soft-excess and the primary continuum are originated from the same physical process. From a physical model fitting, we infer that the soft excess for Ark 120 could be due to a small number of scatterings in the Compton cloud. Using Monte-Carlo simulations, we show that indeed the spectra corresponding to fewer scatterings could provide a steeper soft-excess power-law in the 0.2-3 keV range. Simulated luminosities are found to be in agreement with the observed values.
The Seyfert 1 galaxy Ark 564 was observed with Chandra high energy transmission gratings for 250 ks. We present the high resolution X-ray spectrum that shows several associated absorption lines. The photoionization model requires two warm absorbers with two different ionization states (logU=0.39\pm0.03 and logU=-0.99\pm0.13), both with moderate outflow velocities (~100 km s^-1) and relatively low line of sight column densities (logNH=20.94 and 20.11 cm^-2). The high ionization phase produces absorption lines of OVII, OVIII, NeIX, NeX, MgXI, FeXVII and FeXVIII while the low ionization phase pro…
We present \chandra high energy transmission grating spectra of the narrow-line Seyfert-1 galaxy Ark 564. The spectrum shows numerous absorption lines which are well modeled with low velocity outflow components usually observed in Seyfert galaxies \citep{Gupta2013}. There are, however, some residual absorption lines which are not accounted for by low-velocity outflows. Here we present identifications of the strongest lines as $Kα$ transitions of \oviin (two lines) and \ovin at outflow velocities of $\sim 0.1c$. These lines are detected at $6.9σ$, $6.2σ$, and $4.7σ$ respectively and cannot be d…
We present results from a detailed spectral-timing analysis of a long ~486 ks XMM-Newton observation of the bare Seyfert 1 galaxy Ark 120 which showed alternating diminution and increment in the 0.3-10 keV X-ray flux over four consecutive orbits in 2014. We study the energy-dependent variability of Ark 120 through broad-band X-ray spectroscopy, fractional root-mean-squared (rms) spectral modelling, hardness-intensity diagram and flux-flux analysis. The X-ray (0.3-10 keV) spectra are well fitted by a thermally Comptonized primary continuum with two (blurred and distant) reflection components an…
We analyse eight XMM-Newton observations of the bright Narrow-Line Seyfert 1 galaxy Arakelian 564 (Ark 564). These observations, separated by ~6 days, allow us to look for correlations between the simultaneous UV emission (from the Optical Monitor) with not only the X-ray flux but also with the different X-ray spectral parameters. The X-ray spectra from all the observations are found to be adequately fitted by a double Comptonization model where the soft excess and the hard X-ray power law are represented by thermal Comptonization in a low temperature plasma and hot corona, respectively. Apart…
We report on the results of a multiwavelength monitoring campaign of the bright, nearby Seyfert galaxy, Ark 120 using a ~50-day observing programme with Swift and a ~4-month co-ordinated ground-based observing campaign, predominantly using the Skynet Robotic Telescope Network. We find Ark 120 to be variable at all optical, UV, and X-ray wavelengths, with the variability observed to be well-correlated between wavelength bands on short timescales. We perform cross-correlation analysis across all available wavelength bands, detecting time delays between emission in the X-ray band and the Swift V,…
Over the last few years several models have been proposed to interpret the widespread soft excess observed in the X-ray spectra of type 1 active galactic nuclei (AGN). In particular, reflection from the photoionized accretion disc blurred by relativistic effects has proven to be successful in reproducing both the spectral shape and the variability pattern of many sources. As a further test to this scenario we present the analysis of a recent ~100 ks long Suzaku observation of Arakelian 120, a prototypical 'bare' Seyfert 1 galaxy in which no complex absorption system is expected to mimic a soft…
We present a detailed analysis of xmm X-ray observations of the Narrow line Seyfert-1 (NLS1) galaxy Ark 564 taken between 2000 and 2011. High-resolution X-ray spectroscopy is carried out on the resultant high signal-to-noise stacked spectrum. We find three separate photoionised warm absorbers outflowing at velocities unusually lower than typical NLS1s. Using recombination timescale estimates, improved constraints on the location of these clouds show they could be located beyond 4 pc from the central source. Our estimates of the outflow kinetics suggest that the AGN in Ark 564 is unlikely to af…
We present the first results obtained by the application of the KYNREFREV-reverberation model, which is ready for its use in XSPEC. This model computes the time dependent reflection spectra of the disc as a response to a flash of primary power-law radiation from a point source corona located on the axis of the black hole accretion disc (lamp-post geometry). Full relativistic effects are taken into account. The ionisation of the disc is set for each radius according to the amount of the incident primary flux and the density of the accretion disc. We tested the model by fitting model predictions…
We perform an X-ray spectral analysis of the brightest and cleanest bare AGN known so far, Ark 120, in order to determine the process(es) at work in the vicinity of the SMBH. We present spectral analysis of data from an extensive campaign observing Ark 120 in X-rays with XMM-Newton (4$\times$120 ks, 2014 March 18-24), and NuSTAR (65.5 ks, 2014 March 22). During this very deep X-ray campaign, the source was caught in a high flux state similar to the earlier 2003 XMM-Newton observation, and about twice as bright as the lower-flux observation in 2013. The spectral analysis confirms the "softer wh…
We present simultaneous XMM-Newton and NuSTAR observations of the `bare' Seyfert 1 galaxy, Ark 120, a system in which ionized absorption is absent. The NuSTAR hard X-ray spectral coverage allows us to constrain different models for the excess soft X-ray emission. Among phenomenological models, a cutoff power law best explains the soft X-ray emission. This model likely corresponds to Comptonization of the accretion disk seed UV photons by a population of warm electrons: using Comptonization models, a temperature of ~0.3 keV and an optical depth of ~13 are found. If the UV-to-X-ray optxagnf mode…
Newman College（纽曼学院）；Baselius College（巴瑟留斯学院）；Providence Women’s College（普罗维登斯女子学院）；St. Francis de Sales College（圣方济各沙雷氏学院）；Inter-University Centre for Astronomy & Astrophysics（大学天体物理中心）；Islamic University of Science and Technology（伊斯兰科学与技术大学）
We report the results of a six-month Swift monitoring campaign of Ark120, a prototypical bare Seyfert1 galaxy. The lack of intrinsic absorption combined with the nearly contemporaneous coverage of the UV and X-ray bands makes it possible to investigate the link between the accretion disk and the Comptonization corona. Our observations confirm the presence of substantial temporal variability, with the X-rays characterized by large-amplitude flux changes on timescales of few days, while the variations in the UV bands are smoother on timescales of several weeks. The source also shows spectral var…
Ark 564 is an archetypal Narrow line Seyfert 1 that has been well observed in soft X-rays from 0.3-10 keV, revealing a steep spectrum, strong soft excess, iron K emission line and dramatic variability on the order of hours. Because of its very steep spectrum, observations of the source above 10 keV have been sparse. We report here on the first NuSTAR observation of Ark 564. The source was observed for 200 ks with NuSTAR, 50 ks of which were concurrent with Suzaku observations. NuSTAR and Suzaku observed a dramatic flare, in which the hard emission is clearly delayed with respect to the soft em…
We report on the detection of ultra-fast outflows in the Seyfert~1 galaxy Mrk 590. These outflows are identified through highly blue-shifted absorption lines of OVIII and NeIX in the medium energy grating spectrum and SiXIC and MgXII in the high energy grating spectrum on board Chandra X-ray observatory. Our best fit photoionization model requires two absorber components at outflow velocities of 0.176c and 0.0738c and a third tentative component at 0.0867c. The components at 0.0738c and 0.0867c have high ionization parameter and high column density, similar to other ultra-fast outflows detecte…
We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray excess. The Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in AGNs at present. We use the simultaneous X-ray observation data of XMM-Newton and NuSTAR on Sep. 24th, 2016 to perform spectral analysis in two steps. First, we analyze the time-average spectra by using Warm Corona and Relativistic Reflection models. Moreover, we also explore the Hybrid model, Double Reflection model and Double Warm Corona model. We find that both of Warm Corona and Relati…
We present the spectral/timing properties of the bare Seyfert galaxy Ark 120 through a deep ~420ks XMM-Newton campaign plus recent NuSTAR observations and a ~6-month Swift monitoring campaign. We investigate the spectral decomposition through fractional rms, covariance and difference spectra, finding the mid- to long-timescale (~day-year) variability to be dominated by a relatively smooth, steep component, peaking in the soft X-ray band. Additionally, we find evidence for variable FeK emission red-ward of the FeK-alpha core on long timescales, consistent with previous findings. We detect a cle…
A sample of narrow-line (NLS1) and broad-line Seyfert 1 (BLS1) galaxies observed with Suzaku is presented. The final sample consists of 22 NLS1s and 47 BLS1s, for a total of 69 AGN that are all at low redshift (z<0.5) and exhibit low host galaxy column densities (<10^22 cm^-2). The average spectrum for each object is fit with a toy model to characterise important parameters, including the photon index, soft excess, Compton hump (or hard excess), narrow iron line strength, luminosity and X-ray Eddington ratio (L_x/L_Edd). We confirm previous findings that NLS1s have steeper power laws and highe…
Probing the physics of the accretion flow around active galactic nuclei (AGN) is crucial to understanding their emission mechanisms as well as being able to constrain the geometrical and variability properties of the different regions around them. The soft X-ray excess -- usually observed below $\sim2\,\mathrm{keV}$ in excess of the dominant X-ray powerlaw continuum -- is one prominent feature that is commonly seen in type 1 Seyfert AGN and therefore readily provides a useful diagnostic of the accretion flow mechanism around these systems. NGC 5940 is a Seyfert 1 AGN which reveals strong, prom…
We report on the results from a large observational campaign on the bare Seyfert galaxy Ark 120, jointly carried out in 2014 with XMM-Newton, Chandra, and NuSTAR. The fortunate line of sight to this source, devoid of any significant absorbing material, provides an incomparably clean view to the nuclear regions of an active galaxy. Here we focus on the analysis of the iron fluorescence features, which form a composite emission pattern in the 6$-$7 keV band. The prominent K$α$ line from neutral iron at 6.4 keV is resolved in the Chandra High-Energy Transmission Grating spectrum to a full-width a…
We explore the origin of the strong soft X-ray excess in Narrow Line Seyfert 1 galaxies using spectral-timing information from a 120ks {\it XMM-Newton} observation of PG 1244+026. Spectral fitting alone cannot distinguish between a true additional soft X-ray continuum component and strongly relativistically smeared reflection, but both models also require a separate soft blackbody component. This is most likely intrinsic emission from the disc extending into the lowest energy X-ray bandpass. The {\it RMS} spectra on short timescales (200-5000s) contain both (non-disk) soft excess and power law…
Variable X-ray reverberation in the rapidly accreting AGN Ark 564: the response of the soft excess to the changing geometry of the inner accretion flow
A detailed X-ray Soft Excess of the narrow-line Seyfert-1 galaxy Tonantzintla S180 (Ton s180) present. The study used four XMM-Newton observations for period from the year 2000 to the year 2016 taken from the XMM-Newton archive. Two different models were used to treat the X-ray Soft Excess for each data separately, the first model is power law component and the second one is two black body components. We found that, for all observations, the spectra fitted by using a power law component are poor and the output parameters much different from the previous studies, this model unsuccessfully repro…
We present the first results from a detailed analysis of a new, long ($\sim100$ ks) XMM-Newton observation of the narrow-line Seyfert 1 galaxy PG 1404$+$226 which showed a large-amplitude, rapid X-ray variability by a factor of $\sim7$ in $\sim10$ ks with an exponential rise and a sharp fall in the count rate. We investigate the origin of the soft X-ray excess emission and rapid X-ray variability in the source through time-resolved spectroscopy and fractional root-mean-squared (rms) spectral modeling. The strong soft X-ray excess below 1 keV observed both in the time-averaged and time-resolved…
Fermi-LAT Detection of a Gamma-ray Excess toward the Radio-quiet Narrow-line Seyfert 1 Galaxy 1H 1934-063
Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；University of Chinese Academy of Sciences（中国科学院大学）；Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台暗物质与空间天文重点实验室）；School of Astronomy and Space Science, University of Science and Technology of China（中国科学技术大学天文与空间科学学院）
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. 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 co…
We report the results obtained by a broad-band (0.5-500 keV) data analysis of narrow-line Seyfert 1 galaxy NGC 4748 observed with an XMM-Newton/PN, INTEGRAL/ISGRI and SWIFT/BAT telescopes. This galaxy has a soft X-ray excess that is typical for the class of narrow-line Seyfert 1. The question of the origin of soft excess in such objects is still unclear. We tested and compared two spectral models for the soft X-ray spectra based on the different physical scenarios. The first one is based on the Done & Nayakshin model of two-phase accretion disc in a vertical direction, which includes two refle…
We analysed the archival XMM-Newton data of the radio loud narrow line Seyfert1 galaxy PMN J0948+0022 in the energy range 0.3--10.0 keV. The X-ray data reveal that the spectrum in the 0.3--10.0 keV energy band is not a simple power-law as previously described in the literature. Instead it consists of a power-law with soft excess below 2.5 keV. The X-ray spectrum was fitted with four different models and it was shown the soft excess component of the spectrum in the 0.3--2.5 keV energy range could be described reasonably well within the framework of the thermal Comptonization model as well as re…
The Seyfert 1 galaxy, Ark 120, is a prototype example of the so-called class of bare nucleus AGN, whereby there is no known evidence for the presence of ionized gas along the direct line of sight. Here deep ($>400$ ks exposure), high resolution X-ray spectroscopy of Ark 120 is presented, from XMM-Newton observations which were carried out in March 2014, together with simultaneous Chandra/HETG exposures. The high resolution spectra confirmed the lack of intrinsic absorbing gas associated with Ark 120, with the only X-ray absorption present originating from the ISM of our own Galaxy, with a poss…
We report flux-resolved spectroscopic analysis of the active galactic nucleus (AGN) ESO 103--035 using \textit{NuSTAR} observations. Following an earlier work, we fit the spectra using a thermal Comptonization model with a relativistic reflection component to obtain estimates of the coronal temperature for two flux levels. The coronal temperature was found to increase from 24.0$^{+6.8}_{-3.4}$ to 55.3$^{+54.6}_{-7.2}$ keV (errors at 1-$σ$ confidence level) as the flux increased from $9.8$ to $11.9 \times 10^{-11}$ erg cm$^{-2}$ s$^{-1}$ in the 3--78 keV band. A marginal variation in the high e…
We present an analysis of all XMM-Newton and Suzaku X-ray spectra of the nearby luminous Seyfert galaxy Fairall 9. Confirming previous analyses, we find robust evidence for a broad iron line associated with X-ray reflection from the innermost accretion disk. By fitting a spectral model that includes a relativistically ionized reflection component, we examine the constraints on the inclination of the inner accretion disk and the black hole spin, and the complications introduced by the presence of a photoionized emission line system. Employing multi-epoch fitting, we attempt to obtain robust and…
Ark 564 (z=0.0247) is an X-ray-bright NLS1. By using advanced X-ray timing techniques, an excess of "delayed" emission in the hard X-ray band (4-7.5 keV) following about 1000 seconds after "flaring" light in the soft X-ray band (0.4-1 keV) was recently detected. We report on the X-ray spectral analysis of eight XMM-Newton and one Suzaku observation of Ark 564. High-resolution spectroscopy was performed with the RGS in the soft X-ray band, while broad-band spectroscopy was performed with the EPIC-pn and XIS/PIN instruments. We analysed time-averaged, flux-selected, and time-resolved spectra. De…
The origin of the observed time lags, in nearby active galactic nuclei (AGN), between hard and soft X-ray photons is investigated using new XMM-Newton data for the narrow-line Seyfert I galaxy Ark 564 and existing data for 1H0707-495 and NGC 4051. These AGN have highly variable X-ray light curves that contain frequent, high peaks of emission. The averaged light curve of the peaks is directly measured from the time series, and it is shown that (i) peaks occur at the same time, within the measurement uncertainties, at all X-ray energies, and (ii) there exists a substantial tail of excess emissio…
We explore the nature of Infrared Excess sources (IRX), which are proposed as candidates for luminous L_X(2-10keV)>1e43erg/s Compton Thick (N_H>2e24cm^{-2}$) QSOs at z~2. Lower redshift, z~1, analogues of the distant IRX population are identified by firstly redshifting to z=2 the SEDs of all sources with secure spectroscopic redshifts in the AEGIS (6488) and the GOODS-North (1784) surveys and then selecting those that qualify as IRX sources at that redshift. A total of 19 galaxies are selected. The mean redshift of the sample is $z\approx1$. We do not find strong evidence for Compton Thick QSO…
We analysed new simultaneous \emph{Suzaku} and \emph{Swift} data of the Broad Line Seyfert 1 (BLS1) galaxy CBS 126. A clear Fe emission line and a strong soft excess are present in the source spectra. We fit the spectra with a relativistic reflection model and find the model tends to fit the data with a high iron abundance possibly due to the large soft excess present. By checking the difference and the RMS spectra, we find there is likely an absorption edge at $\sim$ 0.89 keV, which might be caused by oxygen or neon. We also produced an analysis of the time-resolved spectra in order to examin…
We present medium and high resolution X-ray spectral study of a Seyfert 1 galaxy ESO~198--G24 using a long (122 ks) XMM-Newton observation performed in February 2006. The source has a prominent featureless soft X-ray excess below $2\kev$. This makes the source well suited to investigate the origin of the soft excess. Two physical models -- blurred reflection, and optically thick thermal Comptonization in a warm plasma, describe the soft-excess equally well resulting in similar fits in the $0.3-10\kev$ band. These models also yield similar fits to the broad-band UV (Optical Monitor) and X-ray d…
We present a comprehensive flux resolved spectral analysis of the bright Narrow line Seyfert I AGNs, Mrk~335 and Ark~564 using observations by XMM-Newton satellite. The mean and the flux resolved spectra are fitted by an empirical model consisting of two Comptonization components, one for the low energy soft excess and the other for the high energy power-law. A broad Iron line and a couple of low energies edges are required to explain the spectra. For Mrk~335, the 0.3 - 10 keV luminosity relative to the Eddington value, L{$_{X}$}/L$_{Edd}$, varied from 0.002 to 0.06. The index variation can be…
We present a detailed timing and spectral study of an extremely variable narrow-line Seyfert~1 galaxy NGC 4748 using observations in the year 2017 and 2014 performed with AstroSat and XMM-Newton, respectively. Both observations show extremely variable soft and hard X-ray emission that are correlated with each other. In the 2014 data set, the source retains its general behaviour of "softer when brighter" while the 2017 observation exhibits a "harder when brighter" nature. Such changing behaviour is rare in AGNs and is usually observed in the black hole binary systems. The "harder when brighter"…
We study the origin of the soft X-ray excess seen in the 'simple' Narrow Line Seyfert 1 galaxy PG1244+026 using all available spectral-timing information. This object shows the standard switch between soft leading the hard band on long timescales, to the opposite behaviour on short timescales. This is interpreted as a combination of intrinsic fluctuations propagating down through the accretion flow giving the soft lead, together with reflection of the hard X-rays giving the soft lag. We build a full model of the spectral and time variability including both propagation and reflection, and compa…
We have extensively studied the broadband X-ray spectra of the source ESO~141--G055 using all available \xmm{} and \nustar{} observations. We detect a prominent soft excess below 2 keV, a narrow Fe line and a Compton hump (>10 keV). The origin of the soft excess is still debated. We used two models to describe the soft excess: the blurred reflection from the ionized accretion disk and the intrinsic thermal Comptonisation model. We find that both of these models explain the soft excess equally well. We confirm that we do not detect any broad Fe line in the X-ray spectra of this source, although…
We present for the first time the timing and spectral analyses for a narrow-line Seyfert 1 galaxy, SBS 1353+564, using \it{XMM-Newton} and \it{Swift} multi-band observations from 2007 to 2019. Our main results are as follows: 1) The temporal variability of SBS 1353+564 is random, while the hardness ratio is relatively constant over a time span of 13 years; 2) We find a prominent soft X-ray excess feature below 2 keV, which cannot be well described by a simple blackbody component; 3) After comparing the two most prevailing models for interpreting the origin of the soft X-ray excess, we find tha…
We report results on multiband observations from radio to gamma-rays of the two radio-loud narrow-line Seyfert 1 (NLSy1) galaxies PKS 2004-447 and J1548+3511. Both sources show a core-jet structure on parsec scale, while they are unresolved at the arcsecond scale. The high core dominance and the high variability brightness temperature make these NLSy1 galaxies good gamma-ray source candidates. Fermi-LAT detected gamma-ray emission only from PKS 2004-447, with a gamma-ray luminosity comparable to that observed in blazars. No gamma-ray emission is observed for J1548+3511. Both sources are variab…
Narrow-line Seyfert\,1 galaxies (NLS1s) with very small broad-line widths (say, FWHM(\hb) $\la $ 1200\,\kms) represent the extreme type of Seyfert\,1 galaxies that have small black hole masses (\mbh) and/or high Eddington ratios (\redd). Here we study the X-ray properties of a homogeneously and optically selected sample of 13 such objects, termed as very narrow line Seyfert\,1 galaxies (VNLS1s), using archival \xmm\ data. It is found that the Fe K$α$ emission line is at most weak in these objects. A soft X-ray excess is ubiquitous, with the thermal temperatures falling within a strict range of…
We present an analysis of spectrum and variability of the bright reddened narrow line Seyfert 1 galaxy Was~61 using 90 ks archival {\it XMM-Newton} data. The X-ray spectrum in 0.2-10 keV can be characterized by an absorbed power-law plus soft excess and an Fe K$α$ emission line. The power-law spectral index remains constant during the flux variation. The absorbing material is mildly ionized, with a column density of 3.2$\times$10$^{21}$ cm$^{-2}$, and does not appear to vary during the period of the X-ray observation. If the same material causes the optical reddening (E(B-V)$\simeq$0.6 mag), i…
We present a broadband spectral study of the radio-loud narrow-line Seyfert 1 galaxy 1H~0323+342 based on multi-epoch observations performed with NuSTAR on 2014 March 15, and two simultaneous observations performed with Suzaku and Swift on 2009 July 26 and 2013 March 1. We found the presence of a strong soft X-ray excess emission, a broad but weak Fe line and hard X-ray excess emission. We used the blurred reflection (relxill) and the intrinsic disc Comptonization (optxagnf), two physically motivated models, to describe the broadband spectra and to disentangle the disk/corona and jet emission.…
The reprocessed X-ray emission from Active Galactic Nuclei (AGN) is an important diagnostic tool to study the dynamics and geometry of the matter surrounding the supermassive black holes (SMBHs). We present a broadband (optical-UV to hard X-ray) spectral study of the bare Seyfert 1 galaxy, ESO~511--G030, using multi-epoch Suzaku and XMM-Newton data from 2012 and 2007 respectively. The broadband spectra of ESO~511--G030 exhibit a UV bump, a prominent soft-excess below 2 keV, a relatively broad ($σ=0.08 - 0.14$ keV) Fe emission line at 6.4 keV and a weak Compton hump at E > 10 keV. The soft X-ra…
Approximately 10-20% of Active Galactic Nuclei are known to eject powerful jets from the innermost regions. There is very little observational evidence if the jets are powered by spinning black holes and if the accretion disks extend to the innermost regions in radio-loud AGN. Here we study the soft X-ray excess, the hard X-ray spectrum and the optical/UV emission from the radio-loud narrow-line Seyfert 1 galaxy PKS 0558-504 using Suzaku and Swift observations. The broadband X-ray continuum of PKS 0558- 504 consists of a soft X-ray excess emission below 2 keV that is well described by a blackb…
Our objective is to critically assess the X-ray flux variability as a tool for measuring the black hole (BH) mass in active galactic nuclei (AGN). We aim to establish a prescription for estimating BH masses based on measurements of the normalised excess variance from X-ray data. We discuss the minimum requirements in terms of the light-curve duration and X-ray signal-to-noise ratio (S/N) to enable a reliable determination that is comparable to what can be derived from the continuum and emission line reverberation studies. We used the light curves of local Seyfert from the Nuclear Spectroscopic…
The aim of this paper is to study the variability of the warm absorber "clouds of ionised gas within AGN", for the Seyfert 1 galaxies Arakelian 564. The X-ray spectra for four XMM-Newton observations of this object are analysed in EPIC and RGS instruments. These four observations covered a period of eleven years. There are some changes in the ionisation parameter ($ ξ$) of the absorbing matter from one observation to another( $\logξ=0.889 \pm 3.11 \times 10^{-2}$ for year 2000 observation and $0.437 \pm 7.60 \times 10^{-2}$ for year 2001 ). Also the X-ray soft excess is studied for the four ob…
We have carried out an extensive X-ray spectral study of the bare Seyfert-1 galaxy MCG--02--58--22 to ascertain the nature of the X-ray reprocessing media, using observations from Suzaku (2009) and simultaneous observations from XMM-Newton and NuSTAR (2016) . The most significant results of our investigation are: 1. The primary X-ray emission from the corona is constant in these observations, both in terms of the power law slope ($Γ=1.80$) and luminosity ($L_{2-10 \rm keV}= 2.55\times 10^{44} $ erg/s). 2. The soft excess flux decreased by a factor of two in 2016, the Compton hump weakened/vani…
We report on partially overlapping XMM-Newton (~260 ks) and Suzaku (~100 ks) observations of the iron K band in the nearby, bright Seyfert 1 galaxy Mrk 509. The source shows a resolved neutral Fe K line, most probably produced in the outer part of the accretion disc. Moreover, the source shows further emission blue-ward of the 6.4 keV line due to ionized material. This emission is well reproduced by a broad line produced in the accretion disc, while it cannot be easily described by scattering or emission from photo-ionized gas at rest. The summed spectrum of all XMM-Newton observations shows t…
We report on X-ray observations of the radio-intermediate, X-ray bright Seyfert 1 galaxy, III Zw 2, obtained with XMM-Newton, Suzaku, and Swift over the past 17-years. The source brightness varies significantly over yearly time scales, but more modestly over periods of days. Pointed observations with XMM-Newton in 2000 and Suzaku in 2011 show spectral differences despite comparable X-ray fluxes. The Suzaku spectra are consistent with a power law continuum and a narrow Gaussian emission feature at ~6.4 keV, whereas the earlier XMM-Newton spectrum requires a broader Gaussian profile and soft-exc…
We have carried out a systematic analysis of the nearby (z=0.0279) active galaxy Zw 229.015 using multi-epoch, multi-instrument and deep pointed observations with XMM-Newton, Suzaku, Swift and NuSTAR. Spectral and temporal variability are examined in detail on both the long (weeks-to-years) and short (hours) timescales. A deep Suzaku observation of the source shows two distinct spectral states; a bright-soft state and a dim-hard state in which changes in the power law component account for the differences. Partial covering, blurred reflection and soft Comptonisation models describe the X-ray s…
We present results from the spectral analysis of a long XMM-Newton observation of the radio-loud NLS1 galaxy PKS0558-504. The source is highly variable, on all sampled time scales. We did not observe any absorption features in either the soft or hard X-ray band. We found weak evidence for the presence of an iron line at ~6.8 keV, which is indicative of emission from highly ionized iron. The 2-10 keV band spectrum is well fitted by a simple power law model, whose slope steepens with increasing flux, similar to what is observed in other Seyferts as well. The soft excess is variable both in flux …
