scholarly journals Predicting the broad-lines polarization emitted by supermassive binary black holes

2019 ◽  
Vol 623 ◽  
pp. A56 ◽  
Author(s):  
D. Savić ◽  
F. Marin ◽  
L. Č. Popović
Keyword(s):  
Black Holes ◽  
Emission Lines ◽  
Polarization Angle ◽  
Broad Line ◽  
Line Profiles ◽  
Binary Black Holes ◽  
True Nature ◽  
Line Shapes ◽  
Highly Sensitive ◽  
Balmer Lines

Context. Some Type-1 active galactic nuclei (AGN) show extremely asymmetric Balmer lines with the broad peak redshifted or blueshifted by thousands of km s−1. These AGN may be good candidates for supermassive binary black holes (SMBBHs). The complex line shapes can be due to the complex kinematics of the two broad line regions (BLRs). Therefore other methods should be applied to confirm the SMBBHs. One of them is spectropolarimetry. Aims. We rely on numerical modeling of the polarimetry of binary black holes systems, since polarimetry is highly sensitive to geometry, in order to find the specific influence of supermassive binary black hole (SMBBH) geometry and dynamics on polarized parameters across the broad line profiles. We apply our method to SMBBHs in which both components are assumed to be AGN with distances at the subparsec scale. Methods. We used a Monte Carlo radiative transfer code that simulates the geometry, dynamics, and emission pattern of a binary system where two black holes are getting increasingly close. Each gravitational well is accompanied by its own BLR and the whole system is surrounded by an accretion flow from the distant torus. We examined the emission line deformation and predicted the associated polarization that could be observed. Results. We modeled scattering-induced broad line polarization for various BLR geometries with complex kinematics. We find that the presence of SMBBHs can produce complex polarization angle profiles φ and strongly affect the polarized and unpolarized line profiles. Depending on the phase of the SMBBH, the resulting double-peaked emission lines either show red or blue peak dominance, or both the peaks can have the same intensity. In some cases, the whole line profile appears as a single Gaussian line, hiding the true nature of the source. Conclusions. Our results suggest that future observation with the high resolution spectropolarimetry of optical broad emission lines could play an important role in detecting subparsec SMBBHs.

scholarly journals Kinematic signatures of reverberation mapping of close binaries of supermassive black holes in active galactic nuclei

2020 ◽  
Vol 635 ◽  
pp. A1 ◽  
Author(s):  
Andjelka B. Kovačević ◽  
Jian-Min Wang ◽  
Luka Č. Popović
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Transfer Functions ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Close Binary ◽  
Broad Line ◽  
Line Profiles ◽  
Reverberation Mapping ◽  
Line Shapes

Context. An unresolved region in the relative vicinity of the event horizon of a supermassive black holes (SMBH) in active galactic nuclei (AGN) radiates strongly variable optical continuum and broad-line emission flux. These fluxes can be processed into two-dimensional transfer functions (2DTF) of material flows that encrypt various information about these unresolved structures. An intense search for kinematic signatures of reverberation mapping of close binary SMBH (SMBBH) is currently ongoing. Aims. Elliptical SMBBH systems (i.e. both orbits and disc-like broad-line regions (BLR) are elliptic) have not been assessed in 2DTF studies. We aim to numerically infer such a 2DTF because the geometry of the unresolved region is imprinted on their optical emission. Through this, we determine their specific kinematical signatures. Methods. We simulated the geometry and kinematics of SMBBH whose components are on elliptical orbits. Each SMBH had a disc-like elliptical BLR. The SMBHs were active and orbited each other tightly at a subparsec distance. Results. Here we calculate for the first time 2DTF, as defined in the velocity-time delay plane, for several elliptical configurations of SMBBH orbits and their BLRs. We find that these very complex configurations are clearly resolved in maps. These results are distinct from those obtained from circular and disc-wind geometry. We calculate the expected line variability for all SMBBH configurations. We show that the line shapes are influenced by the orbital phase of the SMBBH. Some line profiles resemble observed profiles, but they can also be much deformed to look like those from the disc-wind model. Conclusions. First, our results imply that using our 2DTF, we can detect and quantify kinematic signatures of elliptical SMBBH. Second, the calculated expected line profiles share some intriguing similarities with observed profiles, but also with some profiles that are synthesised in disc-wind models. To overcome the non-uniqueness of the spectral line shapes as markers of SMBBH, they must be accompanied with 2DTF.

SDSS J154751.94+025550 with double-peaked broad H β but single-peaked broad H α: a candidate for central binary black hole system?

2021 ◽  
Vol 507 (4) ◽  
pp. 5205-5213
Author(s):  
XueGuang Zhang
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line ◽  
Line Profiles ◽  
Physical Conditions ◽  
Binary Black Hole ◽  
Sinusoidal Function

ABSTRACT In this manuscript, an interesting blue active galactic nuclei (AGNs) SDSS J154751.94+025550 (=SDSS J1547) is reported with very different line profiles of broad Balmer emission lines: double-peaked broad H β but single-peaked broad H α. SDSS J1547 is the first AGN with detailed discussions on very different line profiles of the broad Balmer emission lines, besides the simply mentioned different broad lines in the candidate for a binary black hole (BBH) system in SDSS J0159+0105. The very different line profiles of the broad Balmer emission lines can be well explained by different physical conditions to two central BLRs in a central BBH system in SDSS J1547. Furthermore, the long-term light curve from CSS can be well described by a sinusoidal function with a periodicity about 2159 d, providing further evidence to support the expected central BBH system in SDSS J1547. Therefore, it is interesting to treat different line profiles of broad Balmer emission lines as intrinsic indicators of central BBH systems in broad line AGN. Under assumptions of BBH systems, 0.125 per cent of broad-line AGN can be expected to have very different line profiles of broad Balmer emission lines. Future study on more broad line AGN with very different line profiles of broad Balmer emission lines could provide further clues on the different line profiles of broad Balmer emission lines as indicator of BBH systems.

scholarly journals Spectrophotometry of Supernovae

1974 ◽  
Vol 3 ◽  
pp. 533-544
Author(s):  
R. P. Kirshner
Keyword(s):  
Emission Lines ◽  
Absorption Lines ◽  
Spectral Energy ◽  
Line Profiles ◽  
Energy Distributions ◽  
Maximum Light ◽  
Balmer Lines ◽  
B Lines ◽  
Infrared Triplet ◽  
The Continuum

AbstractAbsolute spectral energy distributions for supernovae of both types I and II have been obtained. These observations demonstrate three facets of supernova spectra. First, both SN I’s and SN II’s have a continuum that varies slowly and uniformly with time, and which carries the bulk of the radiated flux at early epochs. Second, some lines in both SN I’s and SN II’s have P Cygni profiles: broad emissions flanked on their violet edges by broad absorptions. Third, some lines are common to SN I’s and SN II’s and persist throughout the evolution of the spectrum. The continuum temperatures for both SN I’s and SN II’s are about 10000 K at the earliest times of observation and drop in one month’s time to about 6000 K for SN II’s and about 7000 K for SN I’s. After several months, the continuum may cease to carry the bulk of the flux, which might be in emission lines, but continues to exist, as shown by the presence of absorption lines. The P Cygni line profiles indicate expansion velocities of 15000 km s-1 in SN II’s and 20000 km s-11 in the SN I 1972e in NGC 5253. Line identifications for SN II’s include Hα, Hβ, H and K of Ca II, the Ca II infrared triplet at λ8600, the Na I D-lines, the Mg I b-lines at λ5174, and perhaps Fe II. The [O I] lines λλ6300, 6363 and [Ca II] lines λλ7291, 7323 appear after eight months. For SN I’s, the lines identified are H and K of Ca II, the infrared Ca II lines, the Na I D-lines, and the Mg I b-lines. There is some evidence that Balmer lines are present two weeks after maximum. The strong and puzzling λ4600 features drifts with time from λ4600 near maximum light to λ4750 after 400 days.

scholarly journals Testing the relativistic Doppler boost hypothesis for supermassive binary black holes candidates via broad emission line profiles

2019 ◽  
Vol 491 (3) ◽  
pp. 4023-4030 ◽  
Author(s):  
Zihao Song ◽  
Junqiang Ge ◽  
Youjun Lu ◽  
Xiang Ji
Keyword(s):  
Black Holes ◽  
Emission Lines ◽  
Binary Black Holes ◽  
Broad Emission ◽  
Line Region ◽  
Two Samples ◽  
Region Model ◽  
Orbital Orientation ◽  
The Continuum

ABSTRACT Optical periodicity QSOs found by transient surveys are suggested to be subparsec supermassive binary black holes (BBHs). An intriguing interpretation for the periodicity of some of those QSOs is that the continuum is radiated from the accretion disc associated with the BBH secondary component and modulated by the periodical rotation of the secondary via Doppler-boost effect. Close to edge-on orbital orientation can lead to more significant Doppler-boost effect and thus are preferred for these systems, which is distinct from those normal type-1 QSOs with more or less face-on orientations. Therefore, the profiles of broad lines emitted from these Doppler-modulated systems may be significantly different from other systems that are not Doppler modulated. We investigate the properties of the broad emission lines of optical-periodicity QSOs, including both a sample of QSOs that can be interpreted by the Doppler-modulated effects and a sample that cannot. We find that there is no obvious difference in the profiles and other properties of various (stacked) broad emission lines of these two samples, though a simple broad line region model would suggest significant differences. Our finding raises a challenge to the Doppler boost hypothesis for some of those BBHs candidates with optical periodicity.

scholarly journals The Structure of the Envelopes of Symbiotic Novae

1990 ◽  
Vol 122 ◽  
pp. 431-432
Author(s):  
G.B. Baratta ◽  
A. Damineli Neto ◽  
C. Rossi ◽  
R. Viotti
Keyword(s):  
High Resolution ◽  
Uv Spectra ◽  
Emission Lines ◽  
Broad Line ◽  
Line Profiles ◽  
Composite Spectrum ◽  
Multiple Structure ◽  
Broad Emission ◽  
Light History

Symbiotic novae are composite spectrum stars whose light history is characterized by one single major outburst. At high resolution their optical and UV spectra are very rich of emission lines belonging to a wide ionization range. Generally one can identify both narrow and broad line systems. The latter includes emission lines with multiple structure, broad emission wings, WR features, and P Cygnl lines. Frequently the broad line profiles are largely variable with time. They should be associated with the major stellar outburst. An overview of the problem with extensive references can be found in Viotti (1989).

scholarly journals Broad emission lines for a negatively spinning black hole

2010 ◽  
Vol 6 (S275) ◽  
pp. 100-101
Author(s):  
T. Dauser ◽  
J. Wilms ◽  
C. S. Reynolds ◽  
L. W. Brenneman
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Forthcoming Paper ◽  
Emission Lines ◽  
X Ray ◽  
Line Shapes ◽  
Angular Momenta ◽  
Broad Emission ◽  
Rotating Black Holes ◽  
Limb Darkening

AbstractWe present an extended scheme for the calculation of the profiles of emission lines from accretion disks around rotating black holes. The scheme includes disks with angular momenta which are parallel and antiparallel with respect to the black hole's angular momentum, as both configurations are assumed to be stable (King et al. 2005). Based on a Green's function approach, an arbitrary radius dependence of the disk emissivity and arbitrary limb darkening laws can be easily taken into account, while the amount of precomputed data is significantly reduced with respect to other available models. We discuss line shapes for such disks and present a code for modelling observational data with this scheme in X-ray data analysis programs. A detailed discussion will soon be presented in a forthcoming paper (Dauser et al. 2010).

scholarly journals A search of new samples of active galactic nuclei with low-mass black holes from SDSS

2014 ◽  
Vol 10 (S312) ◽  
pp. 75-76
Author(s):  
H. Liu ◽  
W. Yuan ◽  
H. Zhou ◽  
X.-B. Dong
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Line Width ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line ◽  
Galaxy Sample ◽  
Low Mass ◽  
The Masses ◽  
Larger Sample

AbstractWe report on the progress of our on-going work to search for low-mass black holes (LMBHs) in active galactic nuclei. The masses of black holes are estimated using the broad line width and luminosity obtained from one-epoch optical spectra. As the first step, we fitted the spectra of 1263 objects in the quasar catalog of the SDSS DR10 and obtained accurate measurement of the emission lines. Two AGNs are found to have MBH ~ 106 M⊙. The next step is to analyze the spectra of the DR10 galaxy sample, from which a much larger sample of low-mass AGNs is expected to be obtained.

scholarly journals Accretion in the broad line region of active galactic nuclei

2006 ◽  
Vol 2 (S238) ◽  
pp. 329-330
Author(s):  
E. Bon ◽  
L. Č. Popović ◽  
D. Ilić
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line ◽  
Line Profiles ◽  
Spherical Region ◽  
Broad Line Region ◽  
Broad Emission ◽  
Line Region ◽  
Two Component

AbstractWe modeled the single-peaked Broad Emission Lines (BELs) with two-component model (accretion disk, with surrounding spherical region), comparing it with observational line profiles for a number of Active Galactic Nuclei (AGN). We find that the accretion in the Broad Line Region (BLR) can be present even if the profiles of BELs are single-peaked.

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