Abstract We present a systematic and uniform analysis of NuSTAR data sample 60 SWIFT BAT-selected AGNs with 10–78 keV signal-to-noise ratio (S/N) > 50, 10 which are radio loud. measure their high-energy cutoff E cut or coronal temperature T e using three different spectral models to fit spectra show that threshold in S/N is essential for such measurements. High-energy breaks detected the majority sample, rest, strong constraints on obtained. Strikingly, we find extraordinarily large lower...

Abstract A core sample of 59 unobscured type 1 active galactic nuclei (AGNs) with simultaneous XMM-Newton X-ray and UV observations is compiled from the archives to probe nature soft excess (SE). In first paper this series, our focus centers on scrutinizing spectral profile excess. Of sources, ≈71% (42/59) exhibit power-law-like (po-like) excess, while ≈29% (17/59) blackbody-like (bb-like) We show that a cutoff power law could uniformly characterize both types excesses, median E cut 1.40 keV...

Abstract A recent study on the spectral energy distribution (SED) of AGN combined unobscured X-ray sources from eROSITA eFEDS Survey with high quality optical imaging Subaru’s Hyper Suprime-Cam (HSC). The HSC data enabled accurate host galaxy subtraction as well giving a uniform black hole mass estimator stellar mass. resulting stacked optical/X-ray SEDs for holes at fixed show dramatic transition, where dominating disc component in bright evaporates into an hot plasma below L/LEdd ∼ 0.01....

Investigating how the cutoff energy $E_{\rm cut}$ varies with X-ray flux and photon index $\Gamma$ in individual AGNs opens a new window to probe yet unclear coronal physics. So far variations have only been detected several but different patterns reported. Here we report detections of two Seyfert galaxies multiple NuSTAR exposures. While NGC 3227 monotonically increases $\Gamma$, cut}$-$\Gamma$ relation exhibits $\Lambda$ shape SWIFT J2127.4+5654 ($E_{\rm increasing at $\lesssim$ 2.05,...

A recently released <i>XMM-Newton</i> note revealed a significant calibration issue between nuclear spectroscopic telescope array (<i>NuSTAR)</i> and European Photon Imaging Camera (EPIC) provided an empirical correction to the EPIC effective area. To quantify bias caused by in joint analysis of <i>XMM-NuSTAR</i> spectra verify effectiveness correction, this work, we perform joint-fitting <i>NuSTAR</i> EPIC-pn for large sample 104 observation...

ABSTRACT A unique X-ray occultation event in NGC 6814 during an XMM–Newton observation 2016 has been reported, providing useful information of the absorber and corona. We revisit with aid hardness ratio (HR)–count rate (CR) plot comparison two other absorption-free XMM exposures 2009 2021. exhibits a clear ‘softer-when-brighter’ variation pattern exposures, but exposure significantly deviates from HR–CR plot. While spectral fitting does yield transient Compton-thin absorption corresponding...

Flux-resolved X-ray spectroscopy is widely adopted to investigate the spectral variation of a target between various flux levels. In many cases it done through horizontally splitting single light curve into multiple levels with certain count rate threshold(s). this work we point out there are two hidden biases in approach which could affect analyses under particular circumstances. The first that, when Poisson fluctuations source counts bins non-negligible compared intrinsic variation, would...

Compact radio AGN are thought to be young active galactic nuclei (AGN) at the early stage of evolution, thus ideal laboratory study high-energy emission throughout evolution AGN. In this work, we report for first time detection cutoff ($E_{\rm cut}$), a direct indicator thermal coronal radiation, X-ray in Mrk 348 ($z$ = 0.015), galaxy classified as compact symmetric object. With 100 ks NuSTAR exposure, find that cut}$ ) is firmly detected ($218^{+124}_{-62}$ keV). Fitting with various...

ABSTRACT Compact radio active galactic nuclei (AGNs) are thought to be young AGN at the early stage of evolution, thus ideal laboratory study high-energy emission throughout evolution AGN. In this work, we report for first time detection cutoff (Ecut), a direct indicator thermal coronal radiation, X-ray in Mrk 348 (z = 0.015), galaxy classified as compact symmetric object. With 100 ks Nuclear Spectroscopic Telescope Array exposure, find that (Ecut) is firmly detected ($218^{+124}_{-62}$...

We present the timing analysis of 10 archived \XMM observations with an exposure $>40$ ks Markarian 421. Mrk 421 is brightest high-frequency-peaked BL Lac object (HBL) emitting in X-rays produced by electrons accelerated innermost regions a relativistic jet pointing toward us. For each observation, we construct averaged X-ray spectra 0.5--10 keV band, as well 100 s binned light curves (LCs) various subbands. During these observations, source exhibited intensity states differing close to...

We searched the Chandra and XMM archives for observations of 900 green pea galaxies to find AGN signatures. Green peas are low-mass with prominent emission lines, similar in size star formation rate high-redshift dwarf galaxies. Of 29 found, 9 show X-ray detections $S/N>3$. The 2-10 keV luminosity these sources exceeds $10^{40}~\mathrm{erg~s}^{-1}$, 2 exceeding $10^{41}~\mathrm{erg~s}^{-1}$, suggesting presence intermediate-mass black holes (IMBH) or low-luminosity (LLAGN) BH masses between...

Abstract We present the timing analysis of 10 archived XMM-Newton observations with an exposure >40 ks Markarian 421. Mrk 421 is brightest high-frequency-peaked BL Lac object emitting in X-rays produced by electrons accelerated innermost regions a relativistic jet pointing toward us. For each observation, we construct averaged X-ray spectra 0.5–10 keV band, as well 100 s binned light curves (LCs) various subbands. During these observations, source exhibited intensity states differing...

A recent study on the spectral energy distribution (SED) of AGN combined unobscured X-ray sources from eROSITA eFEDS Survey with high quality optical imaging Subaru's Hyper Suprime-Cam (HSC). The HSC data enabled accurate host galaxy subtraction as well giving a uniform black hole mass estimator stellar mass. resulting stacked optical/X-ray SEDs for holes at fixed show dramatic transition, where dominating disc component in bright evaporates into an hot plasma below $L/L_{\rm Edd}\sim 0.01$....

Utilizing a range of techniques including multi-band light curves, softness ratio analysis, structure functions, rms spectra, cross-correlation and ratios spectra from different intervals, we present comprehensive study the complex X-ray spectral variability in Seyfert 1 galaxy Ark 120, through re-analyzing its six XMM-Newton observations taken between 2003 2014. We find clear ''softer-when-brighter" trend 2--10 keV power-law component over long timescales, with this being timescale...

Abstract Utilizing a range of techniques including multi-band light curves, softness ratio analysis, structure functions, rms spectra, cross-correlation and ratios spectra from different intervals, we present comprehensive study the complex X-ray spectral variability in Seyfert 1 galaxy Ark 120, through re-analyzing its six XMM-Newton observations taken between 2003 2014. We find clear ``softer-when-brighter" trend 2--10 keV power-law component over long timescales, with this being timescale...

A core sample of 59 unobscured type 1 AGNs with simultaneous XMM-Newton X-ray and UV observations is compiled from archive to probe the nature soft excess (SE). In first paper this series, our focus centers on scrutinizing spectral profile excess. Of sources, $\approx$ 71% (42/59) exhibit powerlaw-like (po-like) excess, while 29% (17/59) blackbody-like (bb-like) We show a cut-off powerlaw could uniformly characterize both types excesses, median Ecut 1.40 keV for po-like 0.14 bb-like. For...

Abstract The Nuclear Spectroscopic Telescope Array (NuSTAR) observatory, with its 3–78 keV broadband spectral coverage, enables the detection of high-energy cutoff in a number active galaxies, including several individual radio-loud ones. In this work, we present systematic and uniform analyses 55 spectra for large sample 28 radio 20 which are FR II galaxies. We perform fitting to measure E cut , photon index Γ, reflection factor R Fe K α line equivalent width (EW). Measurements given 13...

A unique X-ray occultation event in NGC 6814 during an XMM-Newton observation 2016 has been reported, providing useful information of the absorber and corona. We revisit with aid hardness ratio (HR) - count rate (CR) plot comparison two other absorption-free XMM exposures 2009 2021. exhibits a clear "softer-when-brighter" variation pattern exposures, but exposure significantly deviates from HR CR plot. While spectral fitting does yield transient Compton-thin absorption corresponding to...

A recently released XMM-Newton technical note has revealed a significant calibration issue between NuSTAR and EPIC, provided an empirical correction to EPIC effective area. To quantify the bias caused by joint analysis of XMM-NuSTAR spectra verify effectiveness correction, in this work we perform joint-fitting EPIC-pn for large sample 104 observation pairs 44 X-ray bright AGN. The were extracted after requiring perfect simultaneity exposures (merging GTIs from two missions) avoid due rapid...

Flux-resolved X-ray spectroscopy is widely adopted to investigate the spectral variation of a target between various flux levels. In many cases it done through horizontally splitting single light curve into multiple levels with certain count rate threshold(s). this work we point out there are two hidden biases in approach which could affect analyses under particular circumstances. The first that, when Poisson fluctuations source counts bins non-negligible compared intrinsic variation, would...