Related papers: Baldwin Effect and Additional BLR Component in AGN…
We present the discovery of a Baldwin effect in 8 nearby Seyfert galaxies for the three most prominent mid-infrared forbidden emission lines observable from the ground that are commonly found in AGN, [ArIII](8.99 micron), [SIV](10.51…
We present the optical and UV emission line properties of 160 X-ray selected AGN taken from the RIXOS survey (including Halpha, Hbeta, [OIII]5007, MgII2798 and CIII]1909). This sample is believed to contain a mixture of absorbed and…
Accretion rates in radio galaxies are typically estimated from optical and total radio flux measurements, incorporating emission from the core, jets, and lobes. These estimates can be used to investigate the link between observed Active…
They are weak, they are small, and they are often overlooked, but they are numerous and an ubiquitous sign of accreting black holes: compact radio cores and jets in low-power AGN. Here I summarize our work concerning these radio cores and…
With their emission mainly coming from a relativistic jet pointing towards us, blazars are fundamental sources to study extragalactic jets and their central engines, consisting of supermassive black holes (SMBHs) fed by accretion discs.…
We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164 in 2008. We analyze the timing of multi-waveband variations in the flux and linear…
Context. Multiwavelength studies of transients in actively accreting supermassive black holes have revealed that large-amplitude variability is frequently linked to significant changes in the optical spectra -- a phenomenon known as…
We present the optical narrow line ratios in an SDSS based sample of 3,175 broad Ha selected type 1 AGN, and explore their positions in the BPT diagrams as a function of the AGN and the host properties. We find the following: 1. The…
We present measurements of broad emission lines and virial estimates of supermassive black hole masses ($M_{BH}$) for a large sample of ultra-hard X-ray selected active galactic nuclei (AGNs) as part of the second data release of the BAT…
We present our latest results on the connection between accretion rate and relativistic jet power in AGN, by using a large sample which includes mostly blazars, but contains also some radio--galaxies. The jet power can be traced by…
We present a spectroscopic analysis of a broad-line active galactic nucleus (AGN) selected as little red dot at $z = 5.3$ behind the Bullet cluster (Bz5.3), based on JWST/NIRCam and NIRSpec data. The detection of strong FeII, OI, and CaII…
Low-luminosity AGNs with low-mass black holes (BHs) in the early universe are fundamental to understanding the BH growth and their co-evolution with the host galaxies. Utilizing JWST NIRCam Wide Field Slitless Spectroscopy (WFSS), we…
The correlation between the jet power and accretion disk luminosity is investigated and analyzed with our model for 7 samples of low luminosity active galactic nuclei (LLAGNs). The main results are: (1) the power-law correlation index…
A systematic analysis of a large sample of radio-loud Active Galactic Nuclei available in the BeppoSAX public archive has been performed. The sample includes 3 Narrow Line Radio Galaxies (NLRG), 10 Broad Line Radio Galaxies (BLRG), 6 Steep…
We study the correlations between the Very Long Baseline Array radio emission at 15 GHz, extended emission at 151 MHz, and optical nuclear emission at 5100 AA for a complete sample of 135 compact jets. We use the partial Kendall's tau…
Although the super-massive (AGN) and stellar mass (XRBs) black holes have many properties in common, the broad emission lines (BELs) are exclusively signatures of the AGN. Based on the detection of these lines from SDSS data bases, there…
The long-term variability study over a range of black hole (BH) mass systems from the microquasars of stellar-mass black holes to the Active Galactic Nuclei (AGNs) of supermassive black holes, in $\gamma$-rays offers new insights into the…
Observations of very-high-energy (VHE, E > 250 GeV) gamma-ray emission from several blazars at z > 0.1 have placed stringent constraints on the elusive spectrum and intensity of the intergalactic infrared background radiation (IIBR).…
The correlation between the kinetic power $P_{\rm jet}$ and intrinsic bolometric luminosity $L_{\rm jet}$ of jets may reveal the underlying jet physics in various black hole systems. Based on the recent work by Nemmen et al. (2012), we…
There is an increasing number of observational evidence that very high energy gamma-rays in radio-loud active galactic nuclei are produced in the direct vicinity of a supermassive black hole (SMBH), close to the base of a relativistic jet.…