scholarly journals Robotic reverberation mapping of the broad-line radio galaxy 3C 120

2020 ◽  
Vol 497 (3) ◽  
pp. 2910-2929 ◽  
Author(s):  
Michael S Hlabathe ◽  
David A Starkey ◽  
Keith Horne ◽  
Encarni Romero-Colmenero ◽  
Steven M Crawford ◽  
...  

ABSTRACT We carried out photometric and spectroscopic observations of the well-studied broad-line radio galaxy 3C 120 with the Las Cumbres Observatory (LCO) global robotic telescope network from 2016 December to 2018 April as part of the LCO AGN Key Project on Reverberation Mapping of Accretion Flows. Here, we present both spectroscopic and photometric reverberation mapping results. We used the interpolated cross-correlation function to perform multiple-line lag measurements in 3C 120. We find the H γ, He ii λ4686, H β, and He i λ5876 lags of $\tau _{\text{cen}} = 18.8_{-1.0}^{+1.3}$, $2.7_{-0.8}^{+0.7}$, $21.2_{-1.0}^{+1.6}$, and $16.9_{-1.1}^{+0.9}$ d, respectively, relative to the V-band continuum. Using the measured lag and rms velocity width of the H β emission line, we determine the mass of the black hole for 3C 120 to be $M=(6.3^{+0.5}_{-0.3})\times 10^7\, (f/5.5)$ M⊙. Our black hole mass measurement is consistent with similar previous studies on 3C 120, but with small uncertainties. In addition, velocity-resolved lags in 3C 120 show a symmetric pattern across the H β line, 25 d at line centre decreasing to 17 d in the line wings at ±4000 km s−1. We also investigate the inter-band continuum lags in 3C 120 and find that they are generally consistent with τ ∝ λ4/3 as predicted from a geometrically thin, optically thick accretion disc. From the continuum lags, we measure the best-fitting value τ0 = 3.5 ± 0.2 d at $\lambda _{\rm 0} = 5477\, \mathring{\rm A}$. It implies a disc size a factor of 1.6 times larger than prediction from the standard disc model with L/LEdd = 0.4. This is consistent with previous studies in which larger than expected disc sizes were measured.

2018 ◽  
Vol 14 (S342) ◽  
pp. 270-271
Author(s):  
C. Alenka Negrete ◽  
Deborah Dultzin ◽  
Paola Marziani ◽  
Jack W. Sulentic ◽  
M. L. Martínez-Aldama

AbstractWe present a method that uses photoionization codes (CLOUDY) to estimate the supermassive black hole masses (MBH) for quasars at low and high redshift. This method is based on the determination of the physical conditions of the broad line region (BLR) using observational diagnostic diagrams from line ratios in the UV. We also considered that the density and metallicity of the BLR in quasars at high z could be different from those at the nearby Universe. The computed black hole masses obtained using this method are in agreement with those derived from the method of reverberation mapping.


2014 ◽  
Vol 568 ◽  
pp. A36 ◽  
Author(s):  
F. Pozo Nuñez ◽  
M. Haas ◽  
M. Ramolla ◽  
C. Bruckmann ◽  
C. Westhues ◽  
...  

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 20
Author(s):  
Aditi Agarwal ◽  
Priyanka Rani ◽  
Raj Prince ◽  
C. S. Stalin ◽  
G. C. Anupama ◽  
...  

We present here the detection of a possible quasi-periodic oscillation (QPO) signal in the X-ray light curve of the active galactic nucleus 3C 120, a broad line radio galaxy at z = 0.033. The hint of a QPO at the 3σ level at 7.1 × 10−6 Hz (∼1.65 days) was detected based on the analysis of X-ray data acquired in the 3–79 keV band by the Nuclear Spectroscopic Telescope Array (NuSTAR). The data, when processed separately in the soft (3–10 keV), hard (10–79 keV) and the total (3–79 keV) bands using four different techniques, namely discrete correlation function, Lomb Scargle periodogram, structure–function, and power spectral density indicated the presence of a QPO. 3C 120 very well fits in the negative correlation in the frequency of the QPO versus the black hole mass (FQPO versus MBH) diagram known for stellar-mass and supermassive black hole sources. Considering the observed signs of QPO to represent the innermost stable orbit of the accretion disk, we found a black hole mass of 1.9×109 M⊙ for a Kerr black hole and 3.04×108 M⊙ for a Schwarzschild black hole. This deduced black hole mass from QPO measurement is a few times larger than the black hole mass obtained from reverberation mapping observations.


2021 ◽  
Vol 918 (2) ◽  
pp. 50
Author(s):  
Kai-Xing Lu ◽  
Jian-Guo Wang ◽  
Zhi-Xiang Zhang ◽  
Ying-Ke Huang ◽  
Liang Xu ◽  
...  

2010 ◽  
Vol 715 (1) ◽  
pp. 355-361 ◽  
Author(s):  
J. León-Tavares ◽  
A. P. Lobanov ◽  
V. H. Chavushyan ◽  
T. G. Arshakian ◽  
V. T. Doroshenko ◽  
...  

2019 ◽  
Vol 625 ◽  
pp. A26
Author(s):  
S. Ronchini ◽  
F. Tombesi ◽  
F. Vagnetti ◽  
F. Panessa ◽  
G. Bruni

Context. We have investigated the dichotomy between jetted and non-jetted active galactic nuclei (AGNs), focusing on the fundamental differences of these two classes in the accretion physics onto the central supermassive black hole (SMBH). We tested the validity of the unification model of AGNs through the characterization of the mutual interaction between accreting and outflowing matter in radio galaxies. Aims. Our aim is to study and constrain the structure, kinematics and physical state of the nuclear environment in the broad line radio galaxy (BLRG) PKS 2251+11. The high X-ray luminosity and the relative proximity make such AGN an ideal candidate for a detailed analysis of the accretion regions in radio galaxies. The investigation will help to shed light on the analogies and differences between the BLRGs and the larger class of radio-quiet Seyfert galaxies and hence on the processes that trigger the launch of a relativistic jet. Methods. We performed a spectral and timing analysis of a ∼64 ks observation of PKS 2251+11 in the X-ray band with XMM-Newton. We modeled the spectrum considering an absorbed power law superimposed to a reflection component. We performed a time-resolved spectral analysis to search for variability of the X-ray flux and of the individual spectral components. Results. We find that the power law has a photon index Γ = 1.8 ± 0.1, absorbed by an ionized partial covering medium with a column density NH = (10.1 ± 0.8) × 1023 cm−2, a ionization parameter log ξ = 1.3 ± 0.1 erg s−1 cm and a covering factor f ≃ 90%. Considering a density of the absorber typical of the broad line region (BLR), its distance from the central SMBH is of the order of r ∼ 0.1 pc. An Fe Kα emission line is found at 6.4 keV, whose intensity shows variability on timescales of hours. We derive that the reflecting material is located at a distance r ≳ 600rs, where rs is the Schwarzschild radius. Conclusions. Concerning the X-ray properties, we found that PKS 2251+11 does not differ significantly from the non-jetted AGNs, confirming the validity of the unified model in describing the inner regions around the central SMBH, but the lack of information regarding the state of the very innermost disk and SMBH spin still leaves unconstrained the origin of the jet.


2014 ◽  
Vol 10 (S313) ◽  
pp. 43-47 ◽  
Author(s):  
J. León Tavares ◽  
V. Chavushyan ◽  
A. Lobanov ◽  
E. Valtaoja ◽  
T. G. Arshakian

AbstractAGN reverberate when the broad emission lines respond to changes of the ionizing thermal continuum emission. Reverberation measurements have been commonly used to estimate the size of the broad-line region (BLR) and the mass of the central black hole. However, reverberation mapping studies have been mostly performed on radio-quiet sources where the contribution of the jet can be neglected. In radio-loud AGN, jets and outflows may affect substantially the relation observed between the ionizing continuum and the line emission. To investigate this relation, we have conducted a series of multi-wavelength studies of radio-loud AGN, combining optical spectral line monitoring with regular VLBI observations. Our results suggest that at least a fraction of the broad-line emitting material can be located in a sub-relativistic outflow ionized by non-thermal continuum emission generated in the jet at large distances (> 1 pc) from the central engine of AGN. This finding may have a strong impact on black hole mass estimates based on measured widths of the broad emission lines and on the gamma-ray emission mechanisms.


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