scholarly journals Explaining temporal variations in the jet position angle of the blazar OJ 287 using its binary black hole central engine model

2021 ◽  
Author(s):  
Lankeswar Dey ◽  
Mauri J Valtonen ◽  
A Gopakumar ◽  
Rocco Lico ◽  
José L Gómez ◽  
...  
Keyword(s):  
Black Hole ◽  
Position Angle ◽  
Temporal Variations ◽  
Optical Observations ◽  
High Angular Resolution ◽  
Orbital Parameters ◽  
Engine Model ◽  
Binary Black Hole ◽  
Central Engine ◽  
Blazar Oj 287

Abstract The bright blazar OJ 287 is the best-known candidate for hosting a supermassive black hole binary system. It inspirals due to the emission of nanohertz gravitational waves (GWs). Observations of historical and predicted quasi-periodic high-brightness flares in its century-long optical lightcurve, allow us to determine the orbital parameters associated with the binary black hole (BBH) central engine. In contrast, the radio jet of OJ 287 has been covered with Very Long Baseline Interferometry (VLBI) observations for only about 30 years and these observations reveal that the position angle (PA) of the jet exhibits temporal variations at both millimetre and centimetre wavelengths. Here we associate the observed PA variations in OJ 287 with the precession of its radio jet. In our model, the evolution of the jet direction can be associated either with the primary black hole (BH) spin evolution or with the precession of the angular momentum direction of the inner region of the accretion disc. Our Bayesian analysis shows that the BBH central engine model, primarily developed from optical observations, can also broadly explain the observed temporal variations in the radio jet of OJ 287 at frequencies of 86, 43, and 15 GHz. Ongoing Global mm-VLBI Array (GMVA) observations of OJ 287 have the potential to verify our predictions for the evolution of its 86 GHz PA values. Additionally, thanks to the extremely high angular resolution that the Event Horizon Telescope (EHT) can provide, we explore the possibility to test our BBH model through the detection of the jet in the secondary black hole .

scholarly journals The Unique Blazar OJ 287 and Its Massive Binary Black Hole Central Engine

Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 108 ◽  
Author(s):  
Lankeswar Dey ◽  
Achamveedu Gopakumar ◽  
Mauri Valtonen ◽  
Stanislaw Zola ◽  
Abhimanyu Susobhanan ◽  
...  
Keyword(s):  
Black Hole ◽  
Strong Field ◽  
Observable Universe ◽  
Engine Model ◽  
Binary Black Hole ◽  
Central Engine ◽  
Optical Light Curve ◽  
General Relativistic ◽  
Improved Model ◽  
Blazar Oj 287

The bright blazar OJ 287 is the best-known candidate for hosting a nanohertz gravitational wave (GW) emitting supermassive binary black hole (SMBBH) in the present observable universe. The binary black hole (BBH) central engine model, proposed by Lehto and Valtonen in 1996, was influenced by the two distinct periodicities inferred from the optical light curve of OJ 287. The current improved model employs an accurate general relativistic description to track the trajectory of the secondary black hole (BH) which is crucial to predict the inherent impact flares of OJ 287. The successful observations of three predicted impact flares open up the possibility of using this BBH system to test general relativity in a hitherto unexplored strong field regime. Additionally, we briefly describe an ongoing effort to interpret observations of OJ 287 in a Bayesian framework.

scholarly journals Promise of Persistent Multi-Messenger Astronomy with the Blazar OJ 287

Galaxies ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Mauri J. Valtonen ◽  
Lankeswar Dey ◽  
Achamveedu Gopakumar ◽  
Staszek Zola ◽  
S. Komossa ◽  
...  
Keyword(s):  
Black Hole ◽  
Spectral Lines ◽  
Host Galaxy ◽  
Central Engine ◽  
Multi Wavelength ◽  
Hole Model ◽  
Electromagnetic Signals ◽  
The Times ◽  
Spectral Survey ◽  
Blazar Oj 287

Successful observations of the seven predicted bremsstrahlung flares from the unique bright blazar OJ 287 firmly point to the presence of a nanohertz gravitational wave (GW) emitting supermassive black hole (SMBH) binary central engine. We present arguments for the continued monitoring of the source in several electromagnetic windows to firmly establish various details of the SMBH binary central engine description for OJ 287. In this article, we explore what more can be known about this system, particularly with regard to accretion and outflows from its two accretion disks. We mainly concentrate on the expected impact of the secondary black hole on the disk of the primary on 3 December 2021 and the resulting electromagnetic signals in the following years. We also predict the times of exceptional fades, and outline their usefulness in the study of the host galaxy. A spectral survey has been carried out, and spectral lines from the secondary were searched for but were not found. The jet of the secondary has been studied and proposals to discover it in future VLBI observations are mentioned. In conclusion, the binary black hole model explains a large number of observations of different kinds in OJ 287. Carefully timed future observations will be able to provide further details of its central engine. Such multi-wavelength and multidisciplinary efforts will be required to pursue multi-messenger nanohertz GW astronomy with OJ 287 in the coming decades.

scholarly journals WISDOM project – IV. A molecular gas dynamical measurement of the supermassive black hole mass in NGC 524

2019 ◽  
Vol 485 (3) ◽  
pp. 4359-4374 ◽  
Author(s):  
Mark D Smith ◽  
Martin Bureau ◽  
Timothy A Davis ◽  
Michele Cappellari ◽  
Lijie Liu ◽  
...  
Keyword(s):  
Black Hole ◽  
Gas Flow ◽  
Line Emission ◽  
Position Angle ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Continuum Source ◽  
Supermassive Black Hole ◽  
Sphere Of Influence ◽  
Dynamical Measurement

ABSTRACT We present high angular resolution (0.3 arcsec or $37\, \mathrm{pc}$) Atacama Large Millimeter/submillimeter Array observations of the CO(2–1) line emission from a central disc in the early-type galaxy NGC 524. This disc is shown to be dynamically relaxed, exhibiting ordered rotation about a compact $1.3\, \mathrm{mm}$ continuum source, which we identify as emission from an active supermassive black hole (SMBH). There is a hole at the centre of the disc slightly larger than the SMBH sphere of influence. An azimuthal distortion of the observed velocity field is found to be due to either a position angle warp or radial gas flow over the inner 2${^{\prime\prime}_{.}}$5. By forward-modelling the observations, we obtain an estimate of the SMBH mass of $4.0^{+3.5}_{-2.0}\times 10^8\,$ M⊙, where the uncertainties are at the 3σ level. The uncertainties are dominated by the poorly constrained inclination and the stellar mass-to-light ratio of this galaxy, and our measurement is consistent with the established correlation between SMBH mass and stellar velocity dispersion. Our result is roughly half that of the previous stellar dynamical measurement, but is consistent within the uncertainties of both. We also present and apply a new tool for modelling complex molecular gas distributions.

scholarly journals X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
Vol 188 ◽  
pp. 388-389
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Optical Observations ◽  
Black Hole Mass ◽  
X Ray ◽  
Upper Limit ◽  
Supergiant Star ◽  
X Ray Binaries ◽  
Two Bodies

About 10 X-ray binaries in our Galaxy and LMC/SMC are considered to contain black hole candidates (BHCs). Among these objects, Cyg X-1 was identified as the first BHC, and it has led BHCs for more than 25 years(Oda 1977, Liang and Nolan 1984). It is a binary system composed of normal blue supergiant star and the X-ray emitting compact object. The orbital kinematics derived from optical observations indicates that the compact object is heavier than ~ 4.8 M⊙ (Herrero 1995), which well exceeds the upper limit mass for a neutron star(Kalogora 1996), where we assume the system consists of only two bodies. This has been the basis for BHC of Cyg X-1.

scholarly journals Optimization of model independent gravitational wave search for binary black hole mergers using machine learning

2021 ◽  
Vol 104 (2) ◽  
Author(s):  
T. Mishra ◽  
B. O’Brien ◽  
V. Gayathri ◽  
M. Szczepańczyk ◽  
S. Bhaumik ◽  
...  
Keyword(s):  
Machine Learning ◽  
Black Hole ◽  
Gravitational Wave ◽  
Binary Black Hole ◽  
Model Independent

scholarly journals Binary black hole spectroscopy: A no-hair test of GW190814 and GW190412

2020 ◽  
Vol 102 (12) ◽  
Author(s):  
Collin D. Capano ◽  
Alexander H. Nitz
Keyword(s):  
Black Hole ◽  
Binary Black Hole

scholarly journals Binary black hole mergers from LIGO/Virgo O1 and O2: Population inference combining confident and marginal events

2020 ◽  
Vol 102 (12) ◽  
Author(s):  
Javier Roulet ◽  
Tejaswi Venumadhav ◽  
Barak Zackay ◽  
Liang Dai ◽  
Matias Zaldarriaga
Keyword(s):  
Black Hole ◽  
Binary Black Hole ◽  
Population Inference
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