Jet Of Cygnus Research Articles

On the origin of the TeV gamma-ray emission from Cygnus X-3

Cygnus X-3 binary system is a famous object studied over the wide range of electromagnetic spectrum. Early detections of ultra-high energy gamma-rays from Cygnus X-3 by Kiel, Havera Park and then by Akeno triggered the construction of several large air shower detectors. Also, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of twenty-year observations of the Cyg X-3 binary at energies 800 GeV - 85 TeV are presented with images, spectra during periods of flaring activity and at low flux periods. The correlation of TeV flux increases with flaring activity at the lower energy range of X-ray and radio emission from the relativistic jets of Cygnus X-3 is found as well as 4.8-hour orbital modulation of TeV γ-ray intensity. Detected modulation of TeV γ-ray emission with orbit and important characteristics of Cyg X-3 such as the high luminosity of the companion star and the close orbit leads to an efficient generation of γ-ray emission through inverse Compton scattering in this object. The different type variability of very high-energy γ-emission and correlation of radiation activity in the wide energy range can provide essential information on the mechanism of particle production up to very high energies.

Particle acceleration in binaries

Cygnus X-3 massive binary system is one of the powerful sources of radio and X-ray emission consisting of an accreting compact object, probably a black hole, with a Wolf-Rayet star companion. Based on the detections of ultra high energy gamma-rays by Kiel and Havera Park, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of long-term observations of the Cyg X-3 binary at energies 800 GeV–85 TeV detected by SHALON in 1995 are presented with images, integral spectra and spectral energy distribution. The identification of source with Cygnus X-3 detected by SHALON was secured by the detection of its 4.8 hour orbital period in TeV gamma-rays. During the whole observation period of Cyg X-3 with SHALON significant flux increases were detected at energies above 0.8 TeV. These TeV flux increases are correlated with flaring activity at a lower energy range of X-ray and/or at observations of Fermi LAT as well as with radio emission from the relativistic jets of Cygnus X-3. The variability of very high-energy gamma-radiation and correlation of radiation activity in the wide energy range can provide essential information on particle mechanism production up to very high energies. Whereas, modulation of very high energy emission connected to the orbital motion of the binary system, provides an understanding of the emission processes, nature and location of particle acceleration.

First 3 mm-VLBI imaging of the two-sided jet in Cygnus A

First 3 mm-VLBI imaging of the two-sided jet in Cygnus A

Composition, Collimation, Contamination: The Jet of Cygnus X‐1

We model the observed size and brightness of the VLBA radio core of the jet in Cygnus X-1 to derive an expression for the jet power as a function of basic jet parameters. We apply this expression to recent constraints on the jet power from observations of a large-scale shocked shell around the source by Gallo and coworkers, which leads us to a set of alternative conclusions: either (1) the jet contains large amounts of protons (?2000 protons per radio-emitting electron), (2) it has a very low volume filling factor of f 3 ? 10-5, (3) the steady, radio-emitting VLBA jet is not the source of the kinetic energy powering the ISM shell, or (4) its asymptotic behavior differs fundamentally from a broad set of plausible analytic jet models.

A dark jet dominates the power output of the stellar black hole Cygnus X-1

Black holes undergoing accretion are thought to emit the bulk of their power in the X-ray band by releasing the gravitational potential energy of the infalling matter. At the same time, they are capable of producing highly collimated jets of energy and particles flowing out of the system with relativistic velocities. Here we show that the 10-solar-mass (10M(o)) black hole in the X-ray binary Cygnus X-1 (refs 3-5) is surrounded by a large-scale (approximately 5 pc in diameter) ring-like structure that appears to be inflated by the inner radio jet. We estimate that in order to sustain the observed emission of the ring, the jet of Cygnus X-1 has to carry a kinetic power that can be as high as the bolometric X-ray luminosity of the binary system. This result may imply that low-luminosity stellar-mass black holes as a whole dissipate the bulk of the liberated accretion power in the form of 'dark', radiatively inefficient relativistic outflows, rather than locally in the X-ray-emitting inflow.

Development of a two-sided relativistic jet in Cygnus X-3

We present multi-epoch radio maps of the microquasar Cygnus X-3 obtained with the Very Large Array (VLA). The observations were carried out as a Target-of-Opportunity (ToO) project triggered by a series of strong (>5 Jy) radio outbursts in September 2000. We find that Cygnus X-3 was well resolved and clearly elongated in the North-South direction at the VLA resolution in the weeks after the triggering events. In particular, the VLA map from our final epoch of observation perfectly shows the development of a two-sided radio jet extending over ~0.05 pc scales. We interpret both the proper motion and the brightness asymmetry between the jet components in the framework of special relativity effects. Assuming a distance of 10 kpc, the true jet velocity that we derive is close to with a large angle with the line of sight. The possible connection between the VLA bipolar jets and the elongated one-sided structures observed at milli-arcsecond angular scales is also discussed.

The nuclear jet and counterjet region of the radio galaxy Cygnus A.

Very-long-baseline interferometry images of the nuclear region of the radio galaxy Cygnus A reveal a pronounced "core" and a knotty jet and counterjet. The knots are moving away from the core at apparent speeds which are subluminal for h = 1 [h = H0/100 km.s-1.Mpc-1;1 parsec (pc) = 3.09 x 10(16)m] and about c for h = 0.5. The jet is aligned with the outer, kiloparsec-scale jet to within 2 degrees. The counterjet has a total flux density at 5 GHz of about one-fifth of that of the jet. In the context of the twin relativistic jet model for active galactic nuclei, the jet in Cygnus A is oriented at an angle to our line of sight of 35-80 degrees and 55-85 degrees, and the intrinsic velocity of the jet fluid is 0.4-0.6c and 0.6-1c for h = 1 and h = 0.5, respectively.

Second epoch VLBI observations of the nuclear jet in Cygnus A: Subluminal jet proper motion measured

We present an image of the core and nuclear jet in Cygnus A at 5 GHz with a resolution of ~1 mas, obtained from "global array" MKIIIA VLBI observations. Comparison of this image (epoch 1991.44) with a previous image made using similar techniques (epoch 1986.89) reveals outward motion of the brighter features in the jet between epochs. The allowed range in velocity for the brightest feature in the jet is: 0.19 c h^-1^ to 0.48 c h^-1^. The peak surface brightness and total flux density of the core and jet have varied < 10% between epochs, although individual knots may have varied by as much as 40%. The pc-scale jet is aligned with the kpc-scale jet to within 20. The core is self-absorbed, with a steeply rising spectrum of index >=0.9 between 5 and 43 GHz. The counterjet in Cygnus A remains elusive. From a combined epoch image we determine a nominal "best" range for the jet to counterjet flux density ratio of: 8 <= R <= 21, with a firm lower limit being: R >= 5, as dictated by extensive analysis of "simulated" data sets. In the context of the twin- symmetric relativistic jet model for powerful radio galaxies and quasars, the conclusions are that the Cygnus A jet must be at an intermediate angle relative to our line of sight (between 11^deg^ and 60^deg^), and must be moving at an intermediate velocity (between 0.37 and 0.74 times the speed of light).

VLBI observations of the nuclear jet in Cygnus A

view Abstract Citations (27) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS VLBI Observations of the Nuclear Jet in Cygnus A Carilli, Christopher L. ; Bartel, Norbert ; Linfield, Roger P. Abstract We present an image of the "core" and inner jet of Cygnus A at an angular resolution of 2 mas obtained from Mark III VLBI observations at 6 cm wavelength with an array of nine antennas. The core is resolved, at least partly due to its being broadened by scattering in the Galactic interstellar medium. The jet has several condensations out to a distance of ~25 mas from the core and has a fairly constant FWHM of ~2.2 mas. The parsec-scale jet points toward the arcsec-scale jet observed with the VLA to within 4^deg^. The ratio between the flux density of the jet and that of the counterjet is > 15:1. From a comparison with an earlier VLBI image of Cygnus A, we find an upper limit to the apparent velocity of the brightest knot in the jet of about 2c, where c is the speed of light (for H_0_ = 60 km s^-1^ Mpc^-1^,q_0_ =0). Publication: The Astronomical Journal Pub Date: November 1991 DOI: 10.1086/115988 Bibcode: 1991AJ....102.1691C Keywords: Cygnus Constellation; Radio Galaxies; Radio Jets (Astronomy); Very Long Base Interferometry; Interstellar Matter; Nuclear Astrophysics; Radio Scattering; Very Large Array (Vla); Astrophysics; RADIO SOURCES: GALAXIES full text sources ADS | data products SIMBAD (4) NED (1)

VLBI Observations of an Expanding Jet in Cygnus X-3

The X-ray binary Cyg X-3 offers a rare opportunity to study the physical conditions of the formation of a relativistic jet. While the central engines of extragalactic jets are generally poorly understood, the infrared and X-ray data on Cyg X-3 allow detailed modelling of the conditions in the inner disk and corona, the source of the jet energy. Study of the periodic nature of particle injection into the jet may yield an important clue to the nature of the particle injection mechanism. And the time scale of jet evolution is much shorter than for extragalactic sources, allowing the possibility of observing a large number of flares to determine general characteristics.

VLBI observations of the jet in Cygnus A

The luminous radio galaxy Cyg A was observed with a five-station US VLBI array at 5 GHz at epoch 1983.25. The jet can be followed from the core to a distance of 9 milliarcsec (mas). Within the limited dynamic range of these observations, it is one-sided (jet:counterjet ratio greater than 12:1). If this one-sidedness is due to Doppler boosting, then (1) the jet must decelerate to a mildly relativistic velocity on a kiloparsec scale, (2) the source cannot lie with 30 deg of the plane of the sky. The jet points directly at the base of the kpc-scale jet seen by Perley, Dreher, and Cowan (1984); the curvature occurs primarily or entirely on a scale of 10-100 kpc. The jet brightness falls off more slowly inside 1 kpc than in other powerful sources. A search for compact structure in the three bright hot spots revealed no structure lower than 3 mas in size with flux greater than 6 mJy.