scholarly journals Estimating black hole masses in obscured AGN using X-rays

2021 ◽  
Vol 502 (3) ◽  
pp. 3329-3342
Author(s):  
Mario Gliozzi ◽  
James K Williams ◽  
Dina A Michel
Keyword(s):  
Black Hole ◽  
Broad Band ◽  
High Rate ◽  
X Rays ◽  
Host Galaxies ◽  
Scaling Method ◽  
X Ray ◽  
Band Spectra ◽  
Black Hole Masses

ABSTRACT Determining the black hole masses in active galactic nuclei (AGN) is of crucial importance to constrain the basic characteristics of their central engines and shed light on their growth and co-evolution with their host galaxies. While the black hole mass (MBH) can be robustly measured with dynamical methods in bright type 1 AGN, where the variable primary emission and the broad-line region are directly observed, a direct measurement is considerably more challenging if not impossible for the vast majority of heavily obscured type 2 AGN. In this work, we tested the validity of an X-ray-based scaling method to constrain the MBH in heavily absorbed AGN. To this end, we utilized a sample of type 2 AGN with good-quality hard X-ray data obtained by the Nuclear Spectroscopic Telescope Array satellite and with MBH dynamically constrained from megamaser measurements. Our results indicate that, when the X-ray broad-band spectra are fitted with physically motivated self-consistent models that properly account for absorption, scattering, and emission-line contributions from the putative torus and constrain the primary X-ray emission, then the X-ray scaling method yields MBH values that are consistent with those determined from megamaser measurements within their respective uncertainties. With this method, we can therefore systematically determine the MBH in any type 2 AGN, provided that they possess good-quality X-ray data and accrete at a moderate to high rate.

scholarly journals Black hole masses from X-rays

2012 ◽  
Vol 8 (S290) ◽  
pp. 371-372
Author(s):  
Xin-Lin Zhou ◽  
Roberto Soria
Keyword(s):  
Black Hole ◽  
X Rays ◽  
X Ray ◽  
Reverberation Mapping ◽  
Photon Index ◽  
Bolometric Correction ◽  
Black Hole Masses ◽  
Intrinsic Scatter

AbstractWe discuss two methods to estimate black hole (BH) masses using X-ray data only: from the X-ray variability amplitude and from the photon index Γ. The first method is based on the anti-correlation between BH mass and X-ray variability amplitude. Using a sample of AGN with BH masses from reverberation mapping, we show that this method shows small intrinsic scatter. The second method is based on the correlation between Γ and both the Eddington ratio Lbol/LEdd and the bolometric correction Lbol/L2−10keV.

scholarly journals Chandra reveals a luminous Compton-thick QSO powering a Lyα blob in a z = 4 starbursting protocluster

2020 ◽  
Vol 642 ◽  
pp. A149
Author(s):  
F. Vito ◽  
W. N. Brandt ◽  
B. D. Lehmer ◽  
C. Vignali ◽  
F. Zou ◽  
...  
Keyword(s):  
Black Hole ◽  
High Redshift ◽  
High Rate ◽  
Host Galaxies ◽  
Gas Reservoirs ◽  
Nuclear Activity ◽  
X Ray ◽  
Supermassive Black Hole ◽  
Nuclear Regions ◽  
Massive Outflow

Context. Galaxy clusters in the local universe descend from high-redshift overdense regions known as protoclusters. The large gas reservoirs and high rate of galaxy interaction in protoclusters are expected to enhance star-formation activity and trigger luminous supermassive black-hole accretion in the nuclear regions of the host galaxies. Aims. We investigated the active galactic nucleus (AGN) content of a gas-rich and starbursting protocluster at z = 4.002, known as the Distant Red Core (DRC). In particular, we search for luminous and possibly obscured AGN in 13 identified members of the structure, and compare the results with protoclusters at lower redshifts. We also test whether a hidden AGN can power the Lyα blob (LAB) detected with VLT/MUSE in the DRC. Methods. We observed all of the identified members of the structure with 139 ks of Chandra ACIS-S imaging. Being less affected by absorption than optical and IR bands, even in the presence of large column densities of obscuring material, X-ray observations are the best tools to detect ongoing nuclear activity in the DRC galaxies. Results. We detect obscured X-ray emission from the two most gas-rich members of the DRC, named DRC-1 and DRC-2. Both of them are resolved into multiple interacting clumps in high-resolution Atacama Large Millimeter Array and Hubble Space Telescope observations. In particular, DRC-2 is found to host a luminous (L2−10 keV ≈ 3 × 1045 erg s−1 ) Compton-thick (NH ≳ 1024 cm−2) quasar (QSO) candidate, comparable to the most luminous QSOs known at all cosmic times. The AGN fraction among DRC members is consistent with results found for lower redshift protoclusters. However, X-ray stacking analysis reveals that supermassive black hole (SMBH) accretion is likely also taking place in other DRC galaxies that are not detected individually by Chandra. Conclusions. The luminous AGN detected in the most gas-rich galaxies in the DRC and the widespread SMBH accretion in the other members, which is suggested by stacking analysis, point toward the presence of a strong link between large gas reservoirs, galaxy interactions, and luminous and obscured nuclear activity in protocluster members. The powerful and obscured QSO detected in DRC-2 is likely powering the nearby LAB detected with VLT/MUSE, possibly through photoionization; however, we propose that the diffuse Lyα emission may be due to gas shocked by a massive outflow launched by DRC-2 over a ≈10 kpc scale.

scholarly journals The black hole X-ray transient Swift J1357.2–0933 as seen with Swift and NuSTAR during its 2017 outburst

2019 ◽  
Vol 485 (3) ◽  
pp. 3064-3075 ◽  
Author(s):  
Aru Beri ◽  
B E Tetarenko ◽  
A Bahramian ◽  
Diego Altamirano ◽  
Poshak Gandhi ◽  
...  
Keyword(s):  
Black Hole ◽  
Coming Out ◽  
Broad Band ◽  
Light Curves ◽  
Optical Data ◽  
Optical Telescope ◽  
X Ray ◽  
Optical Light Curve ◽  
Band Spectra ◽  
Inner Region

ABSTRACT We report on observations of black hole Swift J1357.2–0933, a member of the modest population of very faint X-ray transients. This source has previously shown intense dips in the optical light curve, a phenomena that has been linked to the existence of a ‘unique toroidal structure’ in the inner region of the disc, seen at a high inclination. Our observations, carried out by the Neil Gehrels Swift and NuSTAR X-ray observatories, do not show the presence of intense dips in the optical light curves. We find that the X-ray light curves do not show any features that would straightforwardly support an edge-on configuration or high inclination configuration of the orbit. This is similar to what was seen in the X-ray observations of the source during its 2011 outburst. Moreover, the broad-band spectra were well described with an absorbed power-law model without any signatures of cut-off at energies above 10 keV, or any reflection from the disc or the putative torus. Thus, the X-ray data do not support the unique ‘obscuring torus’ scenario proposed for J1357. We also performed a multiwavelength study using the data of X-ray telescope and Ultraviolet/Optical Telescope aboard Swift, taken during the ∼4.5 months duration of the 2017 outburst. This is consistent with what was previously inferred for this source. We found a correlation between the simultaneous X-ray and ultraviolet/optical data and our study suggests that most of the reprocessed flux must be coming out in the ultraviolet.

scholarly journals Project MOMO: Multiwavelength Observations and Modeling of OJ 287

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 261
Author(s):  
S. Komossa ◽  
D. Grupe ◽  
A. Kraus ◽  
L. C. Gallo ◽  
A. G. Gonzalez ◽  
...  
Keyword(s):  
Black Hole ◽  
Broad Band ◽  
Spectral Energy ◽  
X Rays ◽  
X Ray ◽  
Binary Black Hole ◽  
Accretion Physics ◽  
Radio Measurements ◽  
Multiwavelength Observations

Our project MOMO (Multiwavelength observations and modeling of OJ 287) consists of dedicated, dense, long-term flux and spectroscopic monitoring, and deep follow-up observations of the blazar OJ 287 at >13 frequencies from the radio to the X-ray band since late 2015. In particular, we are using Swift to obtain optical-UV-X-ray spectral energy distributions (SEDs) and the Effelsberg telescope to obtain radio measurements between 2 and 40 GHz. MOMO is the densest long-term monitoring of OJ 287 involving X-rays and broad-band SEDs. The theoretical part of the project aims at understanding jet and accretion physics of the blazar central engine in general and the supermassive binary black hole scenario in particular. Results are presented in a sequence of publications and so far included: detection and detailed analysis of the bright 2016/17 and 2020 outbursts and the long-term light curve; Swift, XMM, and NuSTAR spectroscopy of the 2020 outburst around maximum; and interpretation of selected events in the context of the binary black hole scenario of OJ 287 (papers I–IV). Here, we provide a description of the project MOMO, a summary of previous results, the latest results, and we discuss future prospects.

scholarly journals X-ray properties of reverberation-mapped AGNs with super-Eddington accreting massive black holes

2019 ◽  
Vol 15 (S356) ◽  
pp. 143-143
Author(s):  
Jaya Maithil ◽  
Michael S. Brotherton ◽  
Bin Luo ◽  
Ohad Shemmer ◽  
Sarah C. Gallagher ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rate ◽  
Time Lags ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
X Ray ◽  
Photon Index ◽  
The Impact

AbstractActive Galactic Nuclei (AGN) exhibit multi-wavelength properties that are representative of the underlying physical processes taking place in the vicinity of the accreting supermassive black hole. The black hole mass and the accretion rate are fundamental for understanding the growth of black holes, their evolution, and the impact on the host galaxies. Recent results on reverberation-mapped AGNs show that the highest accretion rate objects have systematic shorter time-lags. These super-Eddington accreting massive black holes (SEAMBHs) show BLR size 3-8 times smaller than predicted by the Radius-Luminosity (R-L) relationship. Hence, the single-epoch virial black hole mass estimates of highly accreting AGNs have an overestimation of a factor of 3-8 times. SEAMBHs likely have a slim accretion disk rather than a thin disk that is diagnostic in X-ray. I will present the extreme X-ray properties of a sample of dozen of SEAMBHs. They indeed have a steep hard X-ray photon index, Γ, and demonstrate a steeper power-law slope, ασx.

scholarly journals Multiwavelength morphological study of active galaxies

2019 ◽  
Vol 15 (S356) ◽  
pp. 295-298
Author(s):  
Betelehem Bilata-Woldeyes ◽  
Mirjana Pović ◽  
Zeleke Beyoro-Amado ◽  
Tilahun Getachew-Woreta ◽  
Shimeles Terefe
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Formation Rate ◽  
Stellar Mass ◽  
Active Galaxies ◽  
Morphological Properties ◽  
X Rays ◽  
Host Galaxies ◽  
X Ray ◽  
Public Data

AbstractStudying the morphology of a large sample of active galaxies at different wavelengths and comparing it with active galactic nuclei (AGN) properties, such as black hole mass (MBH) and Eddington ratio (λEdd), can help us in understanding better the connection between AGN and their host galaxies and the role of nuclear activity in galaxy formation and evolution. By using the BAT-SWIFT hard X-ray public data and by extracting those parameters measured for AGN and by using other public catalogues for parameters such as stellar mass (M*), star formation rate (SFR), bolometric luminosity (Lbol), etc., we studied the multiwavelength morphological properties of host galaxies of ultra-hard X-ray detected AGN and their correlation with other AGN properties. We found that ultra hard X-ray detected AGN can be hosted by all morphological types, but in larger fractions (42%) they seem to be hosted by spirals in optical, to be quiet in radio, and to have compact morphologies in X-rays. When comparing morphologies with other galaxy properties, we found that ultra hard X-ray detected AGN follow previously obtained relations. On the SFR vs. stellar mass diagram, we found that although the majority of sources are located below the main sequence (MS) of star formation (SF), still non-negligible number of sources, with diverse morphologies, is located on and/or above the MS, suggesting that AGN feedback might have more complex influence on the SF in galaxies than simply quenching it, as it was suggested in some of previous studies.

Central Black Hole Masses in Active Galactic Nuclei Inferred from X‐Ray Variability

1998 ◽  
Vol 500 (2) ◽  
pp. 642-659 ◽  
Author(s):  
Kiyoshi Hayashida ◽  
Sigenori Miyamoto ◽  
Shunji Kitamoto ◽  
Hitoshi Negoro ◽  
Hajime Inoue
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Central Black Hole ◽  
X Ray ◽  
Black Hole Masses

scholarly journals The X-ray/UV ratio in active galactic nuclei: dispersion and variability

2018 ◽  
Vol 619 ◽  
pp. A95 ◽  
Author(s):  
E. Chiaraluce ◽  
F. Vagnetti ◽  
F. Tombesi ◽  
M. Paolillo
Keyword(s):  
Black Hole ◽  
Cosmological Parameters ◽  
Multivariate Regression Analysis ◽  
Physical Parameters ◽  
Distance Modulus ◽  
X Rays ◽  
Viewing Angle ◽  
Black Hole Mass ◽  
Intrinsic Variability ◽  
X Ray

Context. The well established negative correlation between the αOX spectral slope and the optical/ultraviolet (UV) luminosity, a by-product of the relation between X-rays and optical/UV luminosity, is affected by relatively large dispersion. The main contributors to this dispersion can be variability in the X-ray/UV ratio and/or changes in fundamental physical parameters. Aims. We want to quantify the contribution from variability within single sources (intra-source dispersion) and that from variations of other quantities different from source to source (inter-source dispersion). Methods. We use archival data from the XMM-Newton Serendipitous Source Catalog (XMMSSC) and from the XMM-OM Serendipitous Ultraviolet Source Survey (XMMOM-SUSS3). We select a sub-sample in order to decrease the dispersion of the relation due to the presence of radio-loud and broad absorption line objects, and that due to absorptions in both X-ray and optical/UV bands. We use the structure function (SF) to estimate the contribution from variability to the dispersion. We analyse the dependence of the residuals of the relation on various physical parameters in order to characterise the inter-source dispersion. Results. We find a total dispersion of σ ∼ 0.12 and find that intrinsic variability contributes 56% of the variance of the αOX − LUV relation. If we select only sources with a larger number of observational epochs (≥3) the dispersion of the relation decreases by approximately 15%. We find weak but significant dependencies of the residuals of the relation on black-hole mass and on Eddington ratio, which are also confirmed by a multivariate regression analysis of αOX as a function of UV luminosity and black-hole mass and/or Eddington ratio. We find a weak positive correlation of both the αOX index and the residuals of the αOX − LUV relation with inclination indicators, such as the full width at half maximum (Hβ) and the equivalent width (EW)[OIII], suggesting a weak increase of X-ray/UV ratio with the viewing angle. This suggests the development of new viewing angle indicators possibly applicable at higher redshifts. Moreover, our results suggest the possibility of selecting a sample of objects, based on their viewing angle and/or black-hole mass and Eddington ratio, for which the αOX − LUV relation is as tight as possible, in light of the use of the optical/UV – X-ray luminosity relation to build a distance modulus (DM)-z plane and estimate cosmological parameters.

scholarly journals In situ damage assessment using synchrotron X-rays in materials loaded by a Hopkinson bar

2014 ◽  
Vol 372 (2015) ◽  
pp. 20130191 ◽  
Author(s):  
Weinong W. Chen ◽  
Matthew C. Hudspeth ◽  
Ben Claus ◽  
Niranjan D. Parab ◽  
John T. Black ◽  
...  
Keyword(s):  
High Speed ◽  
Particle Interaction ◽  
Tensile Failure ◽  
High Rate ◽  
X Rays ◽  
Contrast Imaging ◽  
X Ray ◽  
Damage Initiation ◽  
Dynamic Experiments

Split Hopkinson or Kolsky bars are common high-rate characterization tools for dynamic mechanical behaviour of materials. Stress–strain responses averaged over specimen volume are obtained as a function of strain rate. Specimen deformation histories can be monitored by high-speed imaging on the surface. It has not been possible to track the damage initiation and evolution during the dynamic deformation inside specimens except for a few transparent materials. In this study, we integrated Hopkinson compression/tension bars with high-speed X-ray imaging capabilities. The damage history in a dynamically deforming specimen was monitored in situ using synchrotron radiation via X-ray phase contrast imaging. The effectiveness of the novel union between these two powerful techniques, which opens a new angle for data acquisition in dynamic experiments, is demonstrated by a series of dynamic experiments on a variety of material systems, including particle interaction in granular materials, glass impact cracking, single crystal silicon tensile failure and ligament–bone junction damage.

scholarly journals Review of GRANAT Observations of AGNs

1994 ◽  
Vol 159 ◽  
pp. 63-72 ◽  
Author(s):  
E. Churazov ◽  
M. Gilfanov ◽  
A. Finoguenov ◽  
R. Sunyaev ◽  
M. Chernyakova ◽  
...  
Keyword(s):  
Time Scales ◽  
Gamma Ray ◽  
Broad Band ◽  
Band 3 ◽  
X Rays ◽  
X Ray ◽  
X Ray Background

Brief review of AGNs observations in the X-ray / soft gamma-ray bands with the orbital observatory GRANAT is presented.For three well known bright objects (3C273, NGC4151 and Cen A) broad band (3 keV–few hundreds keV) spectra have been obtained. Imaging capabilities allowed accurate (several arcminutes) identification of these objects with sources of hard X-rays.The spectrum of NGC4151 above ≈ 50 keV was found to be much steeper than that in most of the previous observations, while in standard X-ray band the spectrum agrees with observed previously. The comparison of the observed spectra with that of the X-Ray Background (XRB) indicates that sources similar to NGC4151 could reproduce the shape of XRB spectrum in 3–60 keV band.Cen A was observed in the very low state during most of observations in 1990–1993, except for two observations in 1991. The variability of the hard X-ray flux has been detected on the time scales of several days.

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