Related papers: Measuring H-beta BLR Flows in NGC 5548

We have undertaken a new ground-based monitoring campaign on the BLRG 3C390.3 to improve the measurement of the size of the BLR and to estimate the black hole mass. Optical spectra and g-band images were observed in 2005 using the 2.4m…

Using deep and high-cadence gamma-ray burst (GRB) afterglow data from RATIR, we observe a sharp and achromatic light curve break 12.6 days after the GRB, accompanied by an approximately achromatic bump. Fitting of the optical, NIR, and…

We present results from very high signal-to-noise spectropolarimetric observations of the Seyfert 1 galaxy NGC 3783. Position Angle (PA) changes across the Balmer lines show that the scatterer is resolving the Broad-Emission Line Region…

In order to contribute to the general effort aiming at the improvement of our knowledge about the physical conditions within the Broad Line Region (BLR) of Active Galactic Nuclei (AGN), here we present the results achieved by our analysis…

The colour behaviour of blazars is a subject of much debate. One argument is that the BL Lac objects show bluer-when-brighter chromatism while the flat-spectrum radio quasars (FSRQs) display redder-when-brighter trend. Base on a 3.5-year…

The time delay between flux variations in different wavelength bands can be used to probe the inner regions of active galactic nuclei (AGN). Here, we present the first measurements of the time delay between optical and near-infrared (NIR)…

We report velocity-delay maps for prominent broad emission lines, Ly_alpha, CIV, HeII and H_beta, in the spectrum of NGC5548. The emission-line responses inhabit the interior of a virial envelope. The velocity-delay maps reveal stratified…

From a parent catalog of 561 changing-look active galactic nuclei (CL-AGNs) identified by Guo et al. (2025), we investigate the evolutionary sequence of broad emission lines using a redshift-selected subset (0.35 < z < 0.45) of 54 CL-AGNs…

Line broadening and variability are observational hallmarks of active galactic nuclei which allow us to measure supermassive black hole masses as well as constrain the geometry and kinematics of the emitting gas, with the most precise…

We carried out multi-color optical monitoring of a sample of ten blazars from 2005 to 2011. The sample contains 3 LBLs, 2 IBLs, 4 HBLs, and 1 FSRQ. Our monitoring focused on the long-term variability and the sample included nine BL Lac…

We report on the largest Swift AGN monitoring program, concerning UV/optical variability in Seyferts. From 554 observations, over a 750d period, of the Seyfert galaxy NGC 5548, we see (McHardy et al. 2014) a good overall correlation between…

In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and…

The lag-luminosity relation for gamma-ray bursts (GRBs) is an anti-correlation between the time lag, tau_lag, which represents the delay between the arrival of hard and soft photons, and the isotropic peak luminosity, L. In this paper, we…

We present spectroscopic and photometric monitoring of NGC 3783 conducted throughout the first half of 2020. Time delays between the continuum variations and the response of the broad optical emission lines were clearly detected, and we…

We present an extensive recent multi-band optical photometric observations of the blazar S5 0716+714 carried out over 53 nights with two telescopes in India, two in Bulgaria, one in Serbia, and one in Egypt during 2019 November -- 2022…

Results of a ground-based optical monitoring campaign on NGC5548 in June 1998 are presented. The broad-band fluxes (U,B,V), and the spectrophotometric optical continuum flux F_lambda(5100 A) monotonically decreased in flux while the…

We present the results of a careful analysis of associated absorption systems toward NGC 5548. Most of the well resolved narrow components in the associated system, defined by the Lyman alpha, C IV and N V profiles, show velocity separation…

In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the absorption and emission lines decorrelated from continuum variations. During this time the soft X-ray part…

The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with…

Using VLTI/GRAVITY and SINFONI data, we investigate the sub-pc gas and dust structure around the nearby type 1 AGN hosted by NGC 3783. The K-band coverage of GRAVITY uniquely allows a simultaneous analysis of the size and kinematics of the…