scholarly journals A self-lensing supermassive binary black hole at radio frequencies: the story of Spikey continues

2020 ◽  
Vol 496 (3) ◽  
pp. 3336-3347
Author(s):  
Emma Kun ◽  
Sándor Frey ◽  
Krisztina É Gabányi
Keyword(s):  
Black Hole ◽  
Flux Density ◽  
Structural Model ◽  
High Energy ◽  
Secular Change ◽  
Long Baseline ◽  
Morphological Model ◽  
Optical Light Curve ◽  
5 Ghz ◽  
Jet Structure

ABSTRACT The quasar J1918+4937 was recently suggested to harbour a milliparsec-separation binary supermassive black hole (SMBH), based upon modelling the narrow spike in its high-cadence Kepler optical light curve. Known binary SMBHs are extremely rare, and the tight constraints on the physical and geometric parameters of this object are unique. The high-resolution radio images of J1918+4937 obtained with very long baseline interferometry (VLBI) indicate a rich one-sided jet structure extending to 80 mas. Here we analyse simultaneously made sensitive 1.7- and 5-GHz archive VLBI images as well as snapshot 8.4/8.7-GHz VLBI images of J1918+4937, and show that the appearance of the wiggled jet is consistent with the binary scenario. We develop a jet structural model that handles eccentric orbits. By applying this model to the measured VLBI component positions, we constrain the inclination of the radio jet, as well as the spin angle of the jet emitter SMBH. We find the jet morphological model is consistent with the optical and radio data, and that the secondary SMBH is most likely the jetted one in the system. Furthermore, the decade-long 15-GHz radio flux density monitoring data available for J1918+4937 are compatible with a gradual overall decrease in the total flux density caused by a slow secular change of the jet inclination due to the spin–orbit precession. J1918+4937 could be an efficient high-energy neutrino source if the horizon of the secondary SMBH is rapidly rotating.

scholarly journals The first estimate of radio jet proper motion at z > 5

2014 ◽  
Vol 446 (3) ◽  
pp. 2921-2928 ◽  
Author(s):  
Sándor Frey ◽  
Zsolt Paragi ◽  
Judit O. Fogasy ◽  
Leonid I. Gurvits
Keyword(s):  
High Redshift ◽  
Spectral Energy Distribution ◽  
Lorentz Factor ◽  
Spectral Energy ◽  
Dual Frequency ◽  
The Core ◽  
Long Baseline ◽  
Large Bulk ◽  
5 Ghz ◽  
Jet Structure

Abstract The extremely high-redshift (z = 5.3) radio source SDSS J102623.61+254259.5 (J1026+2542) is among the most distant and most luminous radio-loud active galactic nuclei (AGN) known to date. Its one-sided radio jet structure on milliarcsecond (mas) and ∼10-mas scales typical for blazars was first imaged at 5 GHz with very long baseline interferometry (VLBI) in 2006. Here we report on our dual-frequency (1.7 and 5 GHz) imaging observations performed with the European VLBI Network (EVN) in 2013. The prominent jet structure allows us to identify individual components whose apparent displacement can be detected over the time span of 7.33 yr. This is the first time when jet proper motions are directly derived in a blazar at z > 5. The small values of up to ∼0.1 mas yr−1 are consistent with what is expected in a relativistic cosmological model if redshift is a measure of distance. The apparent superluminal jet speeds, considered tentative because derived from two epochs only, exceed 10 c for three different components along the jet. Based on modelling its spectral energy distribution, J1026+2542 is known to have its X-ray jet oriented close to the line of sight, with significant Doppler boosting and a large bulk Lorentz factor (Γ ≈ 13). The new VLBI observations, indicating ∼2.3 × 1012 K lower limit to the core brightness temperature, are consistent with this picture. The spectral index in the core region is −0.35.

EVOLUTION OF THE RADIO OUTFLOW IN LS 5039

2014 ◽  
Vol 28 ◽  
pp. 1460196
Author(s):  
J. MOLDÓN ◽  
M. RIBÓ ◽  
J. M. PAREDES
Keyword(s):  
Gamma Ray ◽  
Morphological Changes ◽  
High Energy ◽  
Physical Processes ◽  
Long Baseline ◽  
Very High Energy ◽  
Energy Gamma ◽  
Orbital Modulation ◽  
5 Ghz ◽  
Very High

Gamma-ray binaries allow us to study physical processes such as particle acceleration up to TeV energies as well as very high energy gamma-ray emission and absorption with changing geometrical configurations on a periodic basis. These sources produce outflows of radio-emitting particles whose structure can be imaged with very long baseline interferometry (VLBI). We observed the gamma-ray binary LS 5039 with the VLBA at 5 GHz during five consecutive days. We present the observed radio morphological changes, which display a periodic orbital modulation. Multifrequency and multiepoch VLBI observations conducted during the last decade confirm that the morphological periodicity is stable on timescales of years. Using a simple model we show that the observed behavior is compatible with the presence of a young non-accreting pulsar with an outflow behind it.

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.

scholarly journals Relativistic Jets from AGN Viewed at Highest Angular Resolution

Galaxies ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
Kazuhiro Hada
Keyword(s):  
Black Hole ◽  
Spatial Scales ◽  
High Energy ◽  
Rapid Expansion ◽  
Relativistic Jets ◽  
Energy Bands ◽  
Theoretical Understanding ◽  
Broadband Emission ◽  
Long Baseline ◽  
Magnetohydrodynamic Simulations

Accreting supermassive black holes in active galactic nuclei (AGN) produce powerful relativistic jets that shine from radio to GeV/TeV γ-rays. Over the past decade, AGN jets have extensively been studied in various energy bands and our knowledge about the broadband emission and rapid flares are now significantly updated. Meanwhile, the progress of magnetohydrodynamic simulations with a rotating black hole have greatly improved our theoretical understanding of powerful jet production. Nevertheless, it is still challenging to observationally resolve such flaring sites or jet formation regions since the relevant spatial scales are tiny. Observations with very long baseline interferometry (VLBI) are currently the only way to directly access such compact scales. Here we overview some recent progress of VLBI studies of AGN jets. As represented by the successful black hole shadow imaging with the Event Horizon Telescope, the recent rapid expansion of VLBI capability is remarkable. The last decade has also seen a variety of advances thanks to the advent of RadioAstron, GMVA, new VLBI facilities in East Asia as well as to the continued upgrade of VLBA. These instruments have resolved the innermost regions of relativistic jets for a number of objects covering a variety of jetted AGN classes (radio galaxies, blazars, and narrow-line Seyfert 1 galaxies), and the accumulated results start to establish some concrete (and likely universal) picture on the collimation, acceleration, recollimation shocks, magnetic field topology, and the connection to high-energy flares in the innermost part of AGN jets.

scholarly journals Supernova 1986J: a Neutron Star or Black Hole in the Centre?

2017 ◽  
Vol 12 (S331) ◽  
pp. 57-62
Author(s):  
Michael F. Bietenholz
Keyword(s):  
Black Hole ◽  
Flux Density ◽  
Crab Nebula ◽  
Close Binary System ◽  
Close Binary ◽  
Central Component ◽  
Sn 1987A ◽  
Pulsar Wind ◽  
5 Ghz ◽  
The Crab Nebula

AbstractSupernova 1986J is almost the same age as SN 1987A, but was Type IIn, and likely had a massive progenitor. Located at 10 Mpc in NGC 891, it is one of the few supernovae whose radio emission can be resolved using VLBI. We present a new 5-GHz global-VLBI image of SN 1986J from 2014 as well as broadband VLA flux-density measurements. SN 1986J is unusual in that a compact synchrotron radio-emitting component appeared in the centre of the expanding shell of ejecta ~14 yr after the explosion, which now dominates the VLBI image. The central component is stationary to within the uncertainties (<570 km s−1), and it has a marginally resolved HWHM radius of (6.7−3.7+0.7) × 1016cm. The shell has expanded with averagev≃ 5400 km s−1. The central component’s 5-GHz flux density is still increasing with time, and at present it has a 5-GHz νLνluminosity of ~4 × 1035erg s−1, ~20 times that of the Crab Nebula. The central component may be due to a newly formed pulsar wind nebula, or an accreting black hole, or it may be due to interaction of the supernova shock with a highly structured environment left over from a progenitor which was in a close binary system. We discuss the newest observations and the constraints on its nature.

scholarly journals The central pc-scale region in blazars: insights from multi-band observations

2013 ◽  
Vol 9 (S304) ◽  
pp. 257-260
Author(s):  
Tigran G. Arshakian ◽  
Vahram Chavushyan
Keyword(s):  
Black Hole ◽  
High Energy ◽  
Opening Angle ◽  
Radiation Mechanisms ◽  
Long Baseline ◽  
Empirical Relations ◽  
Relativistic Jet ◽  
Line Region ◽  
Γ Ray ◽  
Very Long Baseline Array

AbstractThe empirical relations in the black hole-accretion disk-relativistic jet system and physical processes behind these relations are still poorly understood, partly because they operate close to the black hole within the central light year. Very long baseline array (VLBA) provides unparalleled resolution at 15 GHz with which to observe the jet components at sub-milliarcsecond scales, corresponding to sub-pc-scales for local blazars. We discuss the jet inner structure of blazars, location and radiation mechanisms operating in the innermost parsec-scale region of blazars, and evidence for jet-excited broad-line region (BLR) ouflowing downstream the jet. Outflowing BLR can provide necessary conditions for production of high energy emission along the jet between the base of the jet and the BLR and far beyond the BLR as evidenced by recent observations. Flat spectrum quasars and low synchrotron peaked sources are the most likely objects to host the outfllowing BLR. From the γ-ray absorption arguments, we propose that the jet-excited region of the outflowing BLR in quasars is small and/or gas filling factor is low, and that the orientation and opening angle of the outflowing BLR can lead to relevant γ-ray absorption features observed in quasars.

scholarly journals Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056

2019 ◽  
Vol 633 ◽  
pp. L1 ◽  
Author(s):  
E. Ros ◽  
M. Kadler ◽  
M. Perucho ◽  
B. Boccardi ◽  
H.-M. Cao ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Flux Density ◽  
Gamma Ray ◽  
High Energy ◽  
Density Increase ◽  
High Energy Neutrino ◽  
The Core ◽  
Neutrino Event ◽  
Long Baseline ◽  
Radio Outburst

Context. IceCube has reported a very-high-energy neutrino (IceCube-170922A) in a region containing the blazar TXS 0506+056. Correlated gamma-ray activity has led to the first high-probability association of a high-energy neutrino with an extragalactic source. This blazar has been found to be in a radio outburst during the neutrino event. Aims. Our goal is to probe the sub-milliarcsecond properties of the radio jet right after the neutrino detection and during the further evolution of the radio outburst. Methods. We performed target of opportunity observations at 43 GHz frequency using very long baseline interferometry imaging, corresponding to 7 mm in wavelength, with the Very Long Baseline Array two and eight months after the neutrino event. Results. We produced two images of the radio jet of TXS 0506+056 at 43 GHz with angular resolutions of (0.2 × 1.1) mas and (0.2 × 0.5) mas, respectively. The source shows a compact, high brightness temperature core, albeit not approaching the equipartition limit and a bright and originally very collimated inner jet. Beyond approximately 0.5 mas from the millimeter-VLBI core, the jet loses this tight collimation and expands rapidly. During the months after the neutrino event associated with this source, the overall flux density is rising. This flux density increase happens solely within the core. Notably, the core expands in size with apparent superluminal velocity during these six months so that the brightness temperature drops by a factor of three despite the strong flux density increase. Conclusions. The radio jet of TXS 0506+056 shows strong signs of deceleration and/or a spine-sheath structure within the inner 1 mas, corresponding to about 70–140 pc in deprojected distance, from the millimeter-VLBI core. This structure is consistent with theoretical models that attribute the neutrino and gamma-ray production in TXS 0506+056 to interactions of electrons and protons in the highly relativistic jet spine with external photons originating from a slower moving jet region. Proton loading due to jet-star interactions in the inner host galaxy is suggested as the possible cause of deceleration.

scholarly journals Very Long Baseline Interferometry observations: the closest look at the cores of AGN

2013 ◽  
Vol 9 (S304) ◽  
pp. 71-77
Author(s):  
Marcello Giroletti ◽  
Rocco Lico ◽  
Kazuhiro Hada ◽  
Gabriele Giovannini
Keyword(s):  
Very Long Baseline Interferometry ◽  
High Energy ◽  
Physical Parameters ◽  
Long Baseline ◽  
Superluminal Motion ◽  
Multi Wavelength ◽  
Very High Energy ◽  
Doppler Factor ◽  
Jet Structure ◽  
Very High

AbstractVery Long Baseline Interferometry (VLBI) provides the highest angular resolution achievable in astronomy, reaching sub-milliarcsecond scales. For radio loud AGNs, this offers the unique opportunity to directly image and monitor the fine details of the jet structure, approaching the event horizon in the nearest and most supermassive black holes, like in M87. After a quick review of various VLBI facilities, we present results from recent VLBI monitoring projects on two remarkable radio and high energy sources: the radio galaxy M87 and the BL Lac object Mrk421. For the latter, we present a detailed analysis of the jet structure in total intensity and polarization through the whole 2011, during which a multi-wavelength campaign took place. We reveal flux density variability but no significant changes in the jet structure. In M87, we detect and follow the evolution of the core and of the jet feature HST-1; we reveal superluminal motion of components within HST-1, with a possible connection between ejection of new such components and the occurrence of very high energy flares. Estimates on the physical parameters for both sources are given (Doppler factor, viewing angle, magnetic field, etc.).

THERMAL BEHAVIOR AND IGNITION OF HIGH-ENERGY MATERIALS CONTAINING B, ALB2, AND TIB2

2020 ◽  
Author(s):  
A. G. Korotkikh ◽  
◽  
V. A. Arkhipov ◽  
I. V. Sorokin ◽  
E. A. Selikhova ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Behavior ◽  
Flux Density ◽  
Ignition Delay ◽  
Delay Time ◽  
Heat Flux Density ◽  
Ignition Delay Time ◽  
High Energy ◽  
Energy Materials ◽  
High Energy Materials

The paper presents the results of ignition and thermal behavior for samples of high-energy materials (HEM) based on ammonium perchlorate (AP) and ammonium nitrate (AN), active binder and powders of Al, B, AlB2, and TiB2. A CO2 laser with a heat flux density range of 90-200 W/cm2 was used for studies of ignition. The activation energy and characteristics of ignition for the HEM samples were determined. Also, the ignition delay time and the surface temperature of the reaction layer during the heating and ignition for the HEM samples were determined. It was found that the complete replacement of micron-sized aluminum powder by amorphous boron in a HEM sample leads to a considerable decrease in the ignition delay time by a factor of 2.2-2.8 at the same heat flux density due to high chemical activity and the difference in the oxidation mechanisms of boron particles. The use of aluminum diboride in a HEM sample allows one to reduce the ignition delay time of a HEM sample by a factor of 1.7-2.2. The quasi-stationary ignition temperature is the same for the AlB2-based and AlB12-based HEM samples.

scholarly journals WISDOM project – VII. Molecular gas measurement of the supermassive black hole mass in the elliptical galaxy NGC 7052

2021 ◽  
Vol 503 (4) ◽  
pp. 5984-5996
Author(s):  
Mark D Smith ◽  
Martin Bureau ◽  
Timothy A Davis ◽  
Michele Cappellari ◽  
Lijie Liu ◽  
...  
Keyword(s):  
Black Hole ◽  
Hubble Space Telescope ◽  
Elliptical Galaxy ◽  
Continuum Emission ◽  
Molecular Gas ◽  
Supermassive Black Hole ◽  
Gas Kinematics ◽  
Long Baseline ◽  
Gas Measurement ◽  
Strong Gradient

ABSTRACT Supermassive black hole (SMBH) masses can be measured by resolving the dynamical influences of the SMBHs on tracers of the central potentials. Modern long-baseline interferometers have enabled the use of molecular gas as such a tracer. We present here Atacama Large Millimeter/submillimeter Array observations of the elliptical galaxy NGC 7052 at 0${^{\prime\prime}_{.}}$11 ($37\,$pc) resolution in the 12CO(2-1) line and $1.3\,$ mm continuum emission. This resolution is sufficient to resolve the region in which the potential is dominated by the SMBH. We forward model these observations, using a multi-Gaussian expansion of a Hubble Space Telescope F814W image and a spatially constant mass-to-light ratio to model the stellar mass distribution. We infer an SMBH mass of $2.5\pm 0.3\times 10^{9}\, \mathrm{M_\odot }$ and a stellar I-band mass-to-light ratio of $4.6\pm 0.2\, \mathrm{M_\odot /L_{\odot ,I}}$ (3σ confidence intervals). This SMBH mass is significantly larger than that derived using ionized gas kinematics, which however appears significantly more kinematically disturbed than the molecular gas. We also show that a central molecular gas deficit is likely to be the result of tidal disruption of molecular gas clouds due to the strong gradient in the central gravitational potential.

Sign in / Sign up

Export Citation Format

Share Document