Related papers: Investigating the Variable Continuum Lags in PG 21…
Disk reverberation mapping of a handful of nearby AGN suggest accretion disk sizes which are a factor few too large for their luminosities, apparently at odds with the standard model. Here, we investigate the likely contribution to the…
A generalized approach to reverberation mapping (RM) is presented, which is applicable to broad- and narrow-band photometric data, as well as to spectroscopic observations. It is based on multivariate correlation analysis techniques and, in…
Magnetohydrodynamics (MHD) turbulence can drive significant temperature fluctuations in the accretion disk of an active galactic nucleus (AGN). As a result, the disk can be highly inhomogeneous and has a half-light radius larger than the…
The masses and emission-line region sizes of Active Galactic Nuclei (AGNs) can be measured by ``reverberation-mapping'' (measuring the lag of the emission-line luminosity after changes in the continuum). We use tis technique to calibrate…
The inter-band lags among the optical broad-band continua of active galactic nuclei (AGNs) have been intensively explored over the past decade. However, the nature of the lags remains under debate. Here utilizing two distinct scenarios for…
The variable continuum emission of an active galactic nucleus (AGN) produces corresponding responses in the broad emission lines, which are modulated by light travel delays, and contain information on the physical properties, structure, and…
We present the results of a four-year velocity-resolved reverberation mapping (RM) campaign of the changing-look active galactic nucleus (CL-AGN) NGC 4151 during its outburst phase. By measuring the time lags of the \ha, \hb, \hg, \hei, and…
We present the results from a spectroscopic monitoring campaign to obtain reverberation-mapping measurements and investigate the broad-line region kinematics for active galactic nuclei (AGN) of Mrk~817 and NGC~7469. This campaign was…
Spectroastrometry measures source astrometry as a function of wavelength/velocity. Reverberations of spectroastrometric signals naturally arise in broad-line regions (BLRs) of active galactic nuclei (AGNs) as a result of the continuum…
We present photometric reverberation mapping of the narrow-line Seyfert 1 galaxy ESO399-IG20 performed with the robotic 15 cm telescope VYSOS-6 at the Cerro Armazones Observatory. Through the combination of broad- and narrow-band filters we…
In the standard AGN reverberation-mapping model, variations in broad-line region (BLR) fluxes are predicted from optical continuum variability (taken as a proxy for the ionizing continuum) convolved with a response function that depends on…
Active galactic nuclei (AGN) light curves observed with different wavebands show that the variability in longer wavelength bands lags the variability in shorter wavelength bands. Measuring these lags, or reverberation mapping, is used to…
The innermost regions of Active Galactic Nuclei (AGN) are critical for understanding galaxy evolution and the dynamics of matter near a Supermassive Black Hole (SMBH). Yet, due to smaller angular projections, it is very difficult to resolve…
The X-ray emission from active galactic nuclei (AGN) is highly variable. Measurements of time lags (characterised by lag spectra) between variability in the light curves in energy bands corresponding to directly observed continuum emission…
The changes of broad emission lines should be a crucial issue to understanding the physical properties of changing-look active galactic nucleus (CL-AGN). Here, we present the results of an intensive and homogeneous 6-month long…
Over the last years, a number of broadband reverberation mapping campaigns have been conducted to explore the short-term UV and optical variability of nearby AGN. Despite the extensive data collected, the origin of the observed variability…
We have measured the wavelength-dependent lags between the X-ray, UV and optical bands in the high accretion rate ($L/L_{\rm Edd}\approx40\%$) Active Galactic Nucleus Mrk 110 during two intensive monitoring campaigns in February and…
X-ray reverberation mapping is a powerful technique for probing the innermost accretion disk, whereas continuum reverberation mapping in the UV, optical, and infrared (UVOIR) reveals reprocessing by the rest of the accretion disk and…
A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations from telescopes around the world, reveals that the Hbeta emission…
Robust extragalactic distance measurements are crucial for resolving the persistent discrepancy in the value of the Hubble constant (H$_0$)). Active Galactic Nuclei (AGNs), through their compact and variable broad-line regions (BLRs),…