The nearby Type II active galactic nucleus (AGN) 1ES 1927+654 went through a violent changing-look (CL) event beginning 2017 December during which the optical and UV fluxes increased by four magnitudes over a few months, and broad emission lines newly appeared in the optical/UV. By 2018 July, the X-ray coronal emission had completely vanished, only to reappear a few months later. In this work we report the evolution of the radio, optical, UV and X-rays from the preflare state through mid-2021 with new and archival data from the Very Long Baseline Array, the European VLBI Network, the Very Large Array, the Telescopio Nazionale Galileo, Gran Telescopio Canarias, The Neil Gehrels Swift observatory, and XMM-Newton. The main results from our work are (i) the source has returned to its pre-CL state in optical, UV, and X-ray; the disk–corona relation has been reestablished as it has been in the pre-CL state, with an α OX ∼ 1.02. The optical spectra are dominated by narrow emission lines. (ii) The UV light curve follows a shallower slope of ∝ t −0.91±0.04 compared to that predicted by a tidal disruption event. We conjecture that a magnetic flux inversion event is the possible cause for this enigmatic event. (iii) The compact radio emission which we tracked in the pre-CL (2014), during CL (2018), and post-CL (2021) at spatial scales <1 pc was at its lowest level during the CL event in 2018, nearly contemporaneous with a low 2–10 keV emission. The radio to X-ray ratio of the compact source L Radio/L X−ray ∼ 10−5.5 follows the Güdel–Benz relation, typically found in coronally active stars and several AGNs. (iv) We do not detect any presence of nascent jets at the spatial scales of ∼5–10 pc.

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 relxill model is mainly constrained by the strong soft X-ray excess although the model failed to predict this excess when fitted above 3 keV and extrapolated to lower energies. The joint spectral analysis of the three datasets above 3 keV with this model resulted in a high black hole spin (a > 0.9) and moderate reflection fraction R ∼ 0.5. The optxagnf model fitted to the two simultaneous datasets resulted in an excess emission in the UV band. The simultaneous UV-to-hard X-ray spectra of 1H 0323+342 are best described by a model consisting of a primary X-ray power-law continuum with Γ ∼ 1.8, a blurred reflection component with R ∼ 0.5, Comptonised disk emission as the soft X-ray excess, optical/UV emission from a standard accretion disk around a black hole of mass ∼ 10 7 M ⊙ and a steep power law (Γ ∼ 3 − 3.5) component, most likely the jet emission in the UV band. The fractional RMS variability spectra suggest that both the soft excess and the powerlaw component are variable in nature.

We analyze X-ray light curves of the blazars Mrk 421, PKS 2155−304, and 3C 273 using observations by the Soft X-ray Telescope on board AstroSat and archival XMM-Newton data. We use light curves of length 30–90 ks from three to four epochs for all three blazars. We apply the autoregressive integrated moving average model, which indicates the variability is consistent with short memory processes for most of the epochs. We show that the power spectral density (PSDs) of the X-ray variabilities of the individual blazars are consistent within uncertainties across the epochs. This implies that the construction of broadband PSD using light curves from different epochs is accurate. However, using certain properties of the variance of the light curves and its segments, we show that the blazars exhibit hints of nonstationarity beyond that due to their characteristic red-noise nature in some of those observations. We find a linear relationship between the root-mean-squared amplitude of variability at shorter timescales and the mean flux level at longer timescales for light curves of Mrk 421 across epochs separated by decades as well as light curves spanning 5 days and ∼10 yr. The presence of a flux–rms relation over very different timescales may imply that, similar to the X-ray binaries and Seyfert galaxies, longer and shorter timescale variabilities are connected in blazars.

We have carried out an extensive X-ray spectral analysis of a sample of galaxies exhibiting molecular outflows (MOX sample), to characterize the X-ray properties and investigate the effect of AGN on the dynamical properties of the molecular outflows. We find that the X-ray bolometric correction (L 2−10 keV /L AGN ) of these sources ranges from ∼ 10 −4.5 to 10 −0.5 , with ∼ 70% of the sources below 10 −2 , implying a weak X-ray emission relative to the AGN bolometric luminosity (L AGN ). However, the upper limit on the 2 − 10 keV luminosity (L 2−10 keV, 12µm ) obtained from 12µm flux, following the correlation derived by Asmus et al., are ∼ 0.5 − 3 orders of magnitude larger than the L 2−10 keV values estimated using X-ray spectroscopy, implying a possibility that the MOX sources host normal AGN (not X-ray weak), and their X-ray spectra are extremely obscured. We find that both L 2−10 keV , and L AGN correlates strongly with the molecular outflow velocity as well as the mass outflow rates (Ṁ out ), implying that the central AGN plays an important role in driving these massive outflows. However, we also find statistically significant positive correlations between the starburst emission and MO mass outflow rate, L Starburst vsṀ out , and L 0.6−2 keV vsṀ out , which implies that starbursts can generate and drive the molecular outflows. The correlations of MO velocity andṀ out with AGN luminosities are found to be stronger compared to those with the starburst luminosities. We conclude that both starbursts and AGN play crucial role in driving the large scale MO.# The C-thick sources for which we multiplied the L 2−10 keV obtained in Column 3 by a factor of 100. † The L 2−10 keV of the MOX sources estimated using the hardness ratio method. Columns 1 & 2: The source indices and names. Column 3: The L 2−10 keV values of the MOX sources obtained using X-ray spectral fits and HR method using XMM-Newton and Chandra observations.

The reprocessed X-ray emission from active galactic nuclei is an important diagnostic tool to study the dynamics and geometry of the matter surrounding 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 , a relatively broad ( ) Fe emission line at , and a weak Compton hump at . The soft X-ray excess in ESO 511–G030 can be described either as the thermal Comptonization of disk seed photons by a warm ( ), optically thick ( ), and compact ( ) corona or as the blurred reflection from an untruncated and moderate to highly ionized accretion disk. However, for the blurred reflection, the model requires some extreme configuration of the disk and corona. Both these models prefer a rapidly spinning black hole ( ) and a compact corona, indicating a relativistic origin of the broad Fe emission line. We found an inner disk temperature of that characterizes the UV bump and the SMBH accretes at a sub-Eddington rate ( ).