scholarly journals Multiple black hole system in 4C31.61 (2201+315)

2020 ◽  
Vol 634 ◽  
pp. A101
Author(s):  
J. Roland ◽  
C. Gattano ◽  
S. B. Lambert ◽  
F. Taris
Keyword(s):  
Time Series ◽  
Black Holes ◽  
Black Hole ◽  
Very Long Baseline Interferometry ◽  
Radio Sources ◽  
Mass Ratio ◽  
The Third ◽  
Long Baseline ◽  
Binary Black Hole ◽  
Different Origins

Modeling trajectories of radio components ejected by the nucleus of 4C31.61 (2201+315) and observed by very long baseline interferometry (VLBI) in the frame of the MOJAVE survey suggests that they are ejected from three different origins that possibly host three different supermassive black holes. These origins correspond to three stationary components, one of which one is the VLBI core. Most of the mass of the nucleus is associated with a supermassive binary black hole system whose separation is ≈0.3 milliarc second, that is, a distance of ≈1.3 parsec and the mass ratio is ≈2. In contrast, the mass ratio with respect to the third black hole is ≈1/100. The three origins lie within 0.6 milliarc second, or a distance of ≈2.6 parsec. Based in this structure of the nucleus, we explain the variations observed in the astrometric coordinate time series obtained from VLBI geodetic surveys. This study shows that it is possible to exploit large MOJAVE-like VLBI databases to propose more insights into the structure of the extragalactic radio sources that are targeted by VLBI in geodetic and astrometry programs.

scholarly journals Imaging compact supermassive binary black holes with Very Long Baseline Interferometry

2006 ◽  
Vol 2 (S238) ◽  
pp. 269-272 ◽  
Author(s):  
G. B. Taylor ◽  
C. Rodriguez ◽  
R. T. Zavala ◽  
A. B. Peck ◽  
L. K. Pollack ◽  
...  
Keyword(s):  
Black Holes ◽  
Hot Spots ◽  
Very Long Baseline Interferometry ◽  
Radio Galaxy ◽  
Host Galaxy ◽  
Binary Black Holes ◽  
Long Baseline ◽  
Compact Binary ◽  
Binary Black Hole ◽  
Very Long Baseline Array

AbstractWe report on the discovery of a supermassive binary black-hole (SBBH) system in the radio galaxy 0402+379, with a projected separation between the two black holes of just 7.3 pc. This is the most compact SBBH pair yet imaged by more than two orders of magnitude. These results are based upon multi-frequency imaging using the Very Long Baseline Array (VLBA) which reveal two compact, variable, flat-spectrum, active nuclei within the elliptical host galaxy of 0402+379. Multi-epoch observations from the VLBA also provide constraints on the total mass and dynamics of the system. The two nuclei appear stationary while the jets emanating from the weaker of the two nuclei appear to move out and terminate in bright hot spots. The discovery of this system has implications for the number of compact binary black holes that might be sources of gravitational radiation. The VLBI Imaging and Polarimetry Survey (VIPS) currently underway should discover several more SBBHs.

SPIN EXPANSION FOR HEAD-ON COLLISION OF TWO BLACK HOLES

2011 ◽  
Vol 20 (01) ◽  
pp. 43-57 ◽  
Author(s):  
ZHOUJIAN CAO ◽  
CHENZHOU LIU
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
New Method ◽  
Initial State ◽  
Final State ◽  
The Third ◽  
Binary Black Hole ◽  
Expansion Technique

The spin expansion technique proposed in [L. Boyel, M. Kesden and S. Nissanke, Phys. Rev. Lett.100 (2008) 151101] is very powerful to analyze the relation between the initial state of binary black hole and the final state of the merged black hole. But this technique needs orbital angular momentum to determine the third direction of a triad. Without this triad we cannot get the decomposed components of the involved quantities, and the spin expansion breaks down. The head-on collision of two black holes, whose orbital angular momentum vanishes, falls into this case. In this paper we propose a new method to construct a triad for spin expansion technique. With this new method, we get the same set of equations as in the above-mentioned paper. Furthermore, we use numerical simulations to illustrate the validity of our new method for the head-on collision of two black holes.

scholarly journals A radio parallax to the black hole X-ray binary MAXI J1820+070

2020 ◽  
Vol 493 (1) ◽  
pp. L81-L86 ◽  
Author(s):  
P Atri ◽  
J C A Miller-Jones ◽  
A Bahramian ◽  
R M Plotkin ◽  
A T Deller ◽  
...  
Keyword(s):  
Black Hole ◽  
Inclination Angle ◽  
Precise Measurement ◽  
Very Long Baseline Interferometry ◽  
X Ray ◽  
Long Baseline ◽  
Model Independent ◽  
Jet Velocity ◽  
Very Long Baseline Array

ABSTRACT Using the Very Long Baseline Array and the European Very Long Baseline Interferometry Network, we have made a precise measurement of the radio parallax of the black hole X-ray binary MAXI J1820+070, providing a model-independent distance to the source. Our parallax measurement of (0.348 ± 0.033) mas for MAXI J1820+070 translates to a distance of (2.96 ± 0.33) kpc. This distance implies that the source reached (15 ± 3) per cent of the Eddington luminosity at the peak of its outburst. Further, we use this distance to refine previous estimates of the jet inclination angle, jet velocity, and the mass of the black hole in MAXI J1820+070 to be (63 ± 3)°, (0.89 ± 0.09) c, and (9.2 ± 1.3) M⊙, respectively.

scholarly journals The astrophysical odds of GW151216

2020 ◽  
Vol 498 (2) ◽  
pp. 1905-1910 ◽  
Author(s):  
Gregory Ashton ◽  
Eric Thrane
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Bayesian Method ◽  
Massive Stars ◽  
Stellar Mass ◽  
Population Analyses ◽  
Wave Detection ◽  
Binary Black Hole ◽  
Bona Fide

ABSTRACT The gravitational-wave candidate GW151216 is a proposed binary black hole event from the first observing run of the Advanced LIGO detectors. Not identified as a bona fide signal by the LIGO–Virgo collaboration, there is disagreement as to its authenticity, which is quantified by pastro, the probability that the event is astrophysical in origin. Previous estimates of pastro from different groups range from 0.18 to 0.71, making it unclear whether this event should be included in population analyses, which typically require pastro > 0.5. Whether GW151216 is an astrophysical signal or not has implications for the population properties of stellar-mass black holes and hence the evolution of massive stars. Using the astrophysical odds, a Bayesian method that uses the signal coherence between detectors and a parametrized model of non-astrophysical detector noise, we find that pastro = 0.03, suggesting that GW151216 is unlikely to be a genuine signal. We also analyse GW150914 (the first gravitational-wave detection) and GW151012 (initially considered to be an ambiguous detection) and find pastro values of 1 and 0.997, respectively. We argue that the astrophysical odds presented here improve upon traditional methods for distinguishing signals from noise.

Very long baseline interferometry polarization studies of quasars and active galactic nuclei

1986 ◽  
Vol 64 (4) ◽  
pp. 434-439 ◽  
Author(s):  
J. F. C. Wardle ◽  
D. H. Roberts
Keyword(s):  
Active Galactic Nuclei ◽  
Linear Polarization ◽  
Very Long Baseline Interferometry ◽  
Galactic Nuclei ◽  
Radio Sources ◽  
Long Baseline ◽  
First Results ◽  
Polarization Studies ◽  
Theoretical Issues

We present some first results of a program to map the distribution of linear polarization in compact radio sources with milliarcsecond resolution. We show first-epoch maps of 3C345 and 0735 + 178 and first- and second-epoch maps of OJ287. In general, the polarization is mainly associated with optically thin (jet) components. In the case of OJ287, polarization maps made 1 year apart are strikingly different. We also discuss some of the theoretical issues raised by these observations.

A ROBUST TEST OF GENERAL RELATIVITY IN SPACE

2007 ◽  
Vol 16 (12a) ◽  
pp. 2319-2324 ◽  
Author(s):  
JAMES GRABER
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Quadrupole Moment ◽  
Binary Systems ◽  
High Mass ◽  
Uniqueness Theorems ◽  
Mass Ratio ◽  
Intermediate Mass ◽  
Robust Test

LISA may make it possible to test the black-hole uniqueness theorems of general relativity, also called the no-hair theorems, by Ryan's method of detecting the quadrupole moment of a black hole using high-mass-ratio inspirals. This test can be performed more robustly by observing inspirals in earlier stages, where the simplifications used in making inspiral predictions by the perturbative and post-Newtonian methods are more nearly correct. Current concepts for future missions such as DECIGO and BBO would allow even more stringent tests by this same method. Recently discovered evidence supports the existence of intermediate-mass black holes (IMBHs). Inspirals of binary systems with one IMBH and one stellar-mass black hole would fall into the frequency band of proposed maximum sensitivity for DECIGO and BBO. This would enable us to perform the Ryan test more precisely and more robustly. We explain why tests based on observations earlier in the inspiral are more robust and provide preliminary estimates of possible optimal future observations.

scholarly journals The Astrometric Possibilities of Very-Long-Baseline Interferometry

1986 ◽  
Vol 109 ◽  
pp. 143-155
Author(s):  
D. S. Robertson
Keyword(s):  
Plane Wave ◽  
Arrival Time ◽  
Very Long Baseline Interferometry ◽  
Radio Sources ◽  
Arrival Times ◽  
Long Baseline ◽  
The Difference ◽  
Different Sources

In the application of Very-Long-Baseline Interferometry (VLBI) to astrometric problems the fundamental observable is the difference in the arrival times of a wavefront at two widely separated receiving stations. Since the radio sources being observed are sufficiently distant that the arriving wavefront can be considered to be a plane wave, the differential arrival time is a measure of the component of the baseline in the direction of the source. Equivalently, if the baseline is known, the differential arrival time is sufficient to determine a circle on the sky containing the source. It is easy to show that a minimum of ten observations distributed among three different sources is sufficient to determine all of the source coordinates and the baseline coordinates simultaneously (Robertson, 1975).

scholarly journals Comparing the birth rate of stellar black holes in binary black hole mergers and long gamma-ray bursts

2018 ◽  
Vol 610 ◽  
pp. A58
Author(s):  
J.-L. Atteia ◽  
J.-P. Dezalay ◽  
O. Godet ◽  
A. Klotz ◽  
D. Turpin ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Birth Rate ◽  
Gamma Ray ◽  
Reference Model ◽  
Stellar Mass ◽  
Gamma Ray Bursts ◽  
Birth Rates ◽  
Binary Black Hole ◽  
History Of

Context. Gravitational wave interferometers have proven the existence of a new class of binary black hole (BBH) weighing tens of solar masses, and have provided the first reliable measurement of the rate of coalescing black holes (BHs) in the local Universe. Furthermore, long gamma-ray bursts (GRBs) detected with gamma-ray satellites are believed to be associated with the birth of stellar-mass BHs, providing a measure of the rate of these events across the history of the Universe, thanks to the measure of their cosmological redshift. These two types of sources, which are subject to different detection biases and involve BHs born in different environments with potentially different characteristics, provide complementary information on the birth rate of stellar BHs. Aims. We compare the birth rates of BHs found in BBH mergers and in long GRBs. Methods. We construct a simple model that makes reasonable assumptions on the history of GRB formation, and takes into account some major uncertainties, like the beaming angle of GRBs or the delay between the formation of BBHs and their coalescence. We use this model to evaluate the ratio of the number of stellar mass BHs formed in BBH mergers to those formed in GRBs. Results. We find that in our reference model the birth rate of stellar BHs in BBH mergers represents a significant fraction of the rate of long GRBs and that comparable birth rates are favored by models with moderate beaming angles. These numbers, however, do not consider subluminous GRBs, which may represent another population of sources associated with the birth of stellar mass BHs. We briefly discuss this result in view of our understanding of the progenitors of GRBs and BBH mergers, and we emphasize that this ratio, which will be better constrained in the coming years, can be directly compared with the prediction of stellar evolution models if a single model is used to produce GRBs and BBH mergers with the same assumptions.

scholarly journals Testing the No-Hair Theorem with Sgr A*

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Tim Johannsen
Keyword(s):  
Black Hole ◽  
Free Parameter ◽  
Milky Way ◽  
Very Long Baseline Interferometry ◽  
Angular Size ◽  
High Brightness ◽  
Supermassive Black Hole ◽  
Long Baseline ◽  
Nearby Stars ◽  
Sgr A

The no-hair theorem characterizes the fundamental nature of black holes in general relativity. This theorem can be tested observationally by measuring the mass and spin of a black hole as well as its quadrupole moment, which may deviate from the expected Kerr value. Sgr A*, the supermassive black hole at the center of the Milky Way, is a prime candidate for such tests thanks to its large angular size, high brightness, and rich population of nearby stars. In this paper, I discuss a new theoretical framework for a test of the no-hair theorem that is ideal for imaging observations of Sgr A* with very long baseline interferometry (VLBI). The approach is formulated in terms of a Kerr-like spacetime that depends on a free parameter and is regular everywhere outside of the event horizon. Together with the results from astrometric and timing observations, VLBI imaging of Sgr A* may lead to a secure test of the no-hair theorem.

scholarly journals Quantum leaps of black holes: Magnifying glasses of quantum gravity

2016 ◽  
Vol 25 (12) ◽  
pp. 1644024 ◽  
Author(s):  
Sumanta Chakraborty ◽  
Kinjalk Lochan
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Gravity ◽  
The Third

We show using simple arguments, that the conceptual triad of a classical black hole, semi-classical Hawking emission and geometry quantization is inherently, mutually incompatible. Presence of any two explicitly violates the third. We argue that geometry quantization, if realized in nature, magnifies the quantum gravity features hugely to catapult them into the realm of observational possibilities. We also explore a quantum route towards extremality of the black holes.

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