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 A nearby luminous AGN sample optically selected from Hubble Space Telescope

2019 ◽  
Vol 490 (3) ◽  
pp. 3793-3798 ◽  
Author(s):  
Shuang-Liang Li
Keyword(s):  
Active Galactic Nucleus ◽  
Very Long Baseline Interferometry ◽  
Hubble Space Telescope ◽  
Radio Flux ◽  
Space Telescope ◽  
Very Large Array ◽  
X Ray ◽  
Long Baseline ◽  
Very Long Baseline Array ◽  
The Relationship

ABSTRACT In this work, a nearby luminous active galactic nucleus (AGN) sample is selected from Hubble Space Telescope(HST), where only sources with both X-ray emission observed by Chandra/XMM–Newton and radio flux detected by Very Large Array (VLA)/Very Long Baseline Array (VLBA)/very long baseline interferometry (VLBI)/Multi-Element Radio Linked Interferometer Network (MERLIN) are adopted to keep high precision. Finally, we get a sample of 30 luminous AGNs, which consists of 11 radio-loud AGNs (RLAGN) and 19 radio-quiet AGNs (RQAGN). It is found that the relationship between RUV and αox, which was first reported by Li & Xie in low-luminosity AGNs (LLAGN), and other relationships are all absent in RLAGN, probably due to the complex physical process therein. Our results indicate that the X-ray emission from jet should play an important role in RLAGN and further support the transition of accretion mode between LLAGN and RLAGN. On the other hand, the traditional relationships in RQAGN, such as αox and λ, Γ and λ, are found to be well consistent with previous works.

scholarly journals Energetics of a black hole: constraints on the jet velocity and the nature of the X-ray emitting region in Cyg X-1

2009 ◽  
Vol 400 (3) ◽  
pp. 1512-1520 ◽  
Author(s):  
Julien Malzac ◽  
Renaud Belmont ◽  
Andrew C. Fabian
Keyword(s):  
Black Hole ◽  
X Ray ◽  
Jet Velocity

scholarly journals Estimation of the jet inclination angle for the TDE Swift J1644+57

2019 ◽  
Vol 492 (2) ◽  
pp. 1634-1640
Author(s):  
Sudip Chakraborty ◽  
Sudip Bhattacharyya ◽  
Chandrachur Chakraborty ◽  
A R Rao
Keyword(s):  
Black Hole ◽  
Data Analysis ◽  
Inclination Angle ◽  
Jet Physics ◽  
Triggering Mechanism ◽  
Tidal Disruption ◽  
X Ray ◽  
Upper Limit ◽  
The One ◽  
Disruption Event

ABSTRACT An estimate of the jet inclination angle relative to the accreting black hole’s spin can be useful to probe the jet triggering mechanism and the disc–jet coupling. A tidal disruption event (TDE) of a star by a supermassive spinning black hole provides an excellent astrophysical laboratory to study the jet direction through the possibility of jet precession. In this work, we report a new method to constrain the jet inclination angle β and apply it to the well-sampled jetted TDE Swift J1644+57. This method involves X-ray data analysis and comparisons of jet models with broad properties of the observed X-ray dips, to estimate the upper limit of the extent of the contribution of a plausible jet precession to these X-ray dips. From this limit, we find that β is very likely to be less than ∼15° for Swift J1644+57. Such a well-constrained jet inclination angle could be useful to probe the jet physics. The main advantage of our method is that it does not need to assume an origin of the observed X-ray dips, and the conclusion does not depend on any particular type of jet precession (e.g. the one due to the Lense–Thirring effect) or any specific value of precession frequency or any particular jet model. These make this method reliable and applicable to other jetted TDEs, as well as to other jetted accreting systems.

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 Science with radio pulsar astrometry

2012 ◽  
Vol 8 (S291) ◽  
pp. 269-269 ◽  
Author(s):  
Shami Chatterjee
Keyword(s):  
Gamma Ray ◽  
Radio Pulsars ◽  
Long Baseline ◽  
Pulsar Timing ◽  
Pulse Timing ◽  
Model Independent ◽  
Scientific Results ◽  
Very Long Baseline Array ◽  
Gravitational Wave Background ◽  
Precision Astrometry

AbstractHigh precision astrometry on radio pulsars can provide model-independent estimates of their distances and velocities. Such estimates serve to calibrate models of the Galactic electron density distribution, thereby improving distance estimates for the entire pulsar population. They can provide independent astrometric information for precision pulse timing, reducing the number of fit parameters and thus potentially improving the sensitivity of pulsar timing arrays to the gravitational wave background. Individual neutron stars also serve as laboratories for astrophysics. For example, distances to highly luminous recycled pulsars identified by the Fermi gamma ray space telescope will constrain their energetics and may serve to probe the equation of state for nuclear matter at extremes of density and pressure. Here we provide an update on ongoing astrometry programs with the Very Long Baseline Array and the scientific results from these efforts.

scholarly journals Possible Detection of Quasi-Periodic Oscillations from Sgr A* at 43 GHz

2016 ◽  
Vol 11 (S322) ◽  
pp. 50-51
Author(s):  
Yuhei Iwata ◽  
Tomoharu Oka ◽  
Makoto Miyoshi
Keyword(s):  
Indirect Evidence ◽  
Two Dimensional ◽  
Resonant Oscillation ◽  
Periodic Oscillations ◽  
Gaussian Shape ◽  
X Ray ◽  
Long Baseline ◽  
Spin Parameter ◽  
Sgr A ◽  
Very Long Baseline Array

AbstractQuasi-periodic oscillations (QPOs) are believed to be indirect evidence for black holes. Several authors have reported detections of QPOs from Sgr A*, the nucleus of our Galaxy, in infrared and X-ray wavelength during flare-ups. Miyoshi et al. (2011) reported a tentative detection of QPOs in the 43 GHz light curve of Sgr A* obtained with the Very Long Baseline Array (VLBA). To confirm their detection, we reanalysed their VLBA data very conservatively. The 43 GHz flux was calculated for every 15 seconds by assuming a two-dimensional Gaussian-shape spatial structure. The Lomb-Scargle periodogram of the 43 GHz flux just after a millimeter wave flare of Sgr A*, shows three apparent peaks at 10.2, 14.6 and 32.1 min. Two of them are barely consistent with the previously reported QPOs. Using the resonant oscillation model, we estimated the spin parameter of the Sgr A* black hole to be 0.56 assuming the mass of 4.3 × 106M⊙.

scholarly journals Is OJ 287 a Single Supermassive Black Hole?

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 191
Author(s):  
Marina S. Butuzova ◽  
Alexander B. Pushkarev
Keyword(s):  
Black Hole ◽  
Galactic Nuclei ◽  
Geometrical Parameters ◽  
Observation Data ◽  
Supermassive Black Hole ◽  
Long Baseline ◽  
Photometric Observations ◽  
Long Time ◽  
Component Motion ◽  
Very Long Baseline Array

Light curves for more than century optical photometric observations of the blazar OJ 287 reveals strong flares with a quasi-period of about 12 years. For a long time, this period has been interpreted by processes in a binary black hole system. We propose an alternative explanation for this period, which is based on Doppler factor periodic variations of the emitting region caused by jet helicity. Using multi-epoch very large baseline interferometry (VLBI) observations carried out in a framework of the MOJAVE (Monitoring Of Jets in Active galactic nuclei with VLBA Experiments) program and other VLBA (Very Long Baseline Array) archival experiments at the observing frequency of 15 GHz, we derived geometrical parameters of the jet helix. To reach an agreement between the VLBI and photometric optical observation data, the jet component motion at a small angle to the radial direction is necessary. Such non-radial motion is observed and, together with the jet helical shape, can be naturally explained by the development of the Kelvin–Helmholtz instability in the parsec-scale outflow. In this case, the true precession of the OJ 287 jet may manifest itself in differences between the peak flux values of the 12-year optical flares. A possibility to create this precession due to Lense–Thirring effect of a single supermassive black hole is also discussed.

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.

scholarly journals Jets in AGN at extremely high redshifts

2014 ◽  
Vol 10 (S313) ◽  
pp. 327-328
Author(s):  
Leonid I. Gurvits ◽  
Sándor Frey ◽  
Zsolt Paragi
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Plasma Flow ◽  
Very Long Baseline Interferometry ◽  
Angular Resolution ◽  
Galactic Nuclei ◽  
Physical Parameters ◽  
Long Baseline ◽  
General Terms ◽  
Jet Structure

The jet phenomenon is a trademark of active galactic nuclei (AGN). In most general terms, the current understanding of this phenomenon explains the jet appearance by effects of relativistic plasma physics. The fundamental source of energy that feeds the plasma flow is believed to be the gravitational field of a central supermassive black hole. While the mechanism of energy transfer and a multitude of effects controlling the plasma flow are yet to be understood, major properties of jets are strikingly similar in a broad range of scales from stellar to galactic. They are supposed to be controlled by a limited number of physical parameters, such as the mass of a central black hole and its spin, magnetic field induction and accretion rate. In a very simplified sense, these parameters define the formation of a typical core–jet structure observed at radio wavelengths in the region of the innermost central tens of parsecs in AGN. These core–jet structures are studied in the radio domain by Very Long Baseline Interferometry (VLBI) with milli- and sub-milliarcsecond angular resolution. Such structures are detectable at a broad range of redshifts. If observed at a fixed wavelength, a typical core–jet AGN morphology would appear as having a steep-spectrum jet fading away with the increasing redshift while a flat-spectrum core becoming more dominant. If core–jet AGN constitute the same population of objects throughout the redshift space, the apparent “prominence” of jets at higher redshifts must decrease (Gurvits 1999): well pronounced jets at high z must appear less frequent than at low z.

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