scholarly journals SECONDARY EMISSION BEHIND THE RADIO OUTFLOWS IN GAMMA-RAY BINARIES

2010 ◽  
Vol 19 (06) ◽  
pp. 741-747 ◽  
Author(s):  
VALENTÍ BOSCH-RAMON
Keyword(s):  
Radio Emission ◽  
Binary Systems ◽  
Gamma Ray ◽  
Orbital Motion ◽  
Compact Object ◽  
Radio Spectrum ◽  
Secondary Emission ◽  
Primary Star ◽  
Structure Extension ◽  
The Impact

Several binary systems consisting of a massive star and a compact object have been detected above 100 GeV in the Galaxy. In most of these sources, gamma-rays show a modulation associated to the orbital motion, which means that the emitter should not be too far from the bright primary star. This implies that gamma-ray absorption will be non-negligible, and large amounts of secondary electron–positron pairs will be created in the stellar surroundings. In this work, we show that the radio emission from these pairs should be accounted for when interpreting the radio spectrum, variability, and morphology found in gamma-ray binaries. Relevant features of the secondary radio emission are the relatively hard spectrum, the orbital motion of the radio peak center and the radio structure extension following a spiral-like trajectory. The impact of the stellar wind free–free absorption should not be neglected.

scholarly journals Nonthermal emission from high-mass microquasar jets affected by orbital motion

2018 ◽  
Vol 618 ◽  
pp. A146 ◽  
Author(s):  
E. Molina ◽  
V. Bosch-Ramon
Keyword(s):  
Radio Emission ◽  
Stellar Wind ◽  
Gamma Ray ◽  
Orbital Motion ◽  
Source Parameters ◽  
High Energy ◽  
High Mass ◽  
Broadband Emission ◽  
Inverse Compton ◽  
The Impact

Context. The stellar wind in high-mass microquasars should interact with the jet. This interaction, coupled with orbital motion, is expected to make the jet follow a helical, nonballistic trajectory. The jet energy dissipated by this interaction, through shocks for example, could lead to nonthermal activity on scales significantly larger than the system size. Aims. We calculate the broadband emission from a jet affected by the impact of the stellar wind and orbital motion in a high-mass microquasar. Methods. We employ a prescription for the helical trajectory of a jet in a system with a circular orbit. Subsequently, assuming electron acceleration at the onset of the helical jet region, we compute the spatial and energy distribution of these electrons, and their synchrotron and inverse Compton emission including gamma-ray absorption effects. Results. For typical source parameters, significant radio, X- and gamma-ray luminosities are predicted. The scales on which the emission is produced may reduce, but not erase, orbital variability of the inverse Compton emission. The wind and orbital effects on the radio emission morphology could be studied using very long baseline interferometric techniques. Conclusions. We predict significant broadband emission, modulated by orbital motion, from a helical jet in a high-mass microquasar. This emission may be hard to disentangle from radiation of the binary itself, although the light curve features, extended radio emission, and a moderate opacity to very high-energy gamma rays, could help to identify the contribution from an extended (helical) jet region.

VACUUM DISCHARGE AS A POSSIBLE SOURCE OF GAMMA-RAY BURSTS

2000 ◽  
Vol 09 (02) ◽  
pp. 185-192
Author(s):  
G. MAO ◽  
S. CHIBA ◽  
W. GREINER ◽  
K. OYAMATSU
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Ambient Medium ◽  
Critical Density ◽  
Compact Object ◽  
Dense Matter ◽  
Initial Energy ◽  
Strong Interactions ◽  
Γ Ray ◽  
The Impact

We propose that spontaneous particle–anti-particle pair creations from the discharged vacuum caused by the strong interactions in dense matter are major sources of γ-ray bursts. Two neutron star collisions or black-hole-neutron star mergers at cosmological distance could produce a compact object with its density exceeding the critical density for pair creations. The emitted anti-particles annihilate with corresponding particles at the ambient medium. This releases a large amount of energy. We discuss the spontaneous [Formula: see text] pair creations within two neutron star collision and estimate the exploded energy from [Formula: see text] annihilation processes. The total energy could be around 1051–1053 erg depending on the impact parameter of colliding neutron stars. This value fits well into the range of the initial energy of the most energetic γ-ray bursts.

Understanding jets in post-AGB close binaries

2018 ◽  
Vol 14 (S343) ◽  
pp. 355-356
Author(s):  
Dylan Bollen ◽  
Devika Kamath ◽  
Hans Van Winckel ◽  
Orsola De Marco
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Orbital Motion ◽  
Young Stellar Objects ◽  
Close Binaries ◽  
Primary Star ◽  
Stellar Objects ◽  
Optical Time ◽  
The Impact ◽  
Stellar Mergers

AbstractWe have discovered jets in post-AGB binaries. The orbital motion allows us to carry out tomography of the jet as light from the primary star shines through the jet cone. Jets play a major role in many astrophysical environments, from young stellar objects to galaxies. They are also used to study the energetics of accretion phenomena in systems such as red transients and stellar mergers. We use high-resolution, optical, time-series spectra to constrain theories of jet launching, and the impact of jets on the evolution of these post-AGB binaries.

scholarly journals Black hole mass accretion rates and efficiency factors for over 750 AGN and multiple GBH

2020 ◽  
Vol 500 (1) ◽  
pp. 215-231
Author(s):  
Ruth A Daly
Keyword(s):  
Black Hole ◽  
Radio Emission ◽  
Binary Systems ◽  
Accretion Rate ◽  
Beam Power ◽  
Black Hole Mass ◽  
X Ray ◽  
Accretion Rates ◽  
Efficiency Factors ◽  
The Impact

ABSTRACT Mass accretion rates in dimensionless and physical units, and efficiency factors describing the total radiant luminosity of the disc and the beam power of the outflow are obtained and studied here for samples of black hole systems with outflows. Four samples of sources including 576 LINERs, 100 classical double (FRII) radio sources, 80 relatively local AGN, and 103 measurements of four stellar mass X-ray binary systems, referred to as Galactic Black Holes (GBHs), are included in the study. All of the sources have highly collimated outflows leading to compact radio emission or powerful extended (FRII) radio emission. The properties of each of the full samples are explored, as are those of the four individual GBH, and sub-types of the FRII and local AGN samples. Source types and sub-types that have high, medium, and low values of accretion rates and efficiency factors are identified and studied. A new efficiency factor that describes the relative impact of black hole spin and mass accretion rate on the beam power is defined and studied, and is found to provide a new and interesting diagnostic. Mass accretion rates for 13 sources and efficiency factors for 6 sources are compared with values obtained independently, and indicate that similar values are obtained with independent methods. The mass accretion rates and efficiency factors obtained here substantially increase the number of values available, and improve our understanding of their relationship to source types. The redshift dependence of quantities is presented and the impact on the results is discussed.

scholarly journals Hints about the multiplicity of WR 133 based on multiepoch radio observations

2019 ◽  
Vol 623 ◽  
pp. A163 ◽  
Author(s):  
M. De Becker ◽  
N. L. Isequilla ◽  
P. Benaglia
Keyword(s):  
Radio Emission ◽  
Binary Systems ◽  
Thermal Emission ◽  
Radio Spectrum ◽  
Particle Accelerator ◽  
Stellar Winds ◽  
Apparent Contradiction ◽  
Thermal Radio Emission ◽  
Massive Binary Systems ◽  
Thermal Emission Spectrum

Several tens of massive binary systems display indirect, or even strong evidence for non-thermal radio emission, hence their particle accelerator status. These objects are referred to as particle-accelerating colliding-wind binaries (PACWBs). WR 133 is one of the shortest period Wolf-Rayet + O systems in this category, and is therefore critical to characterize the boundaries of the parameter space adequate for particle acceleration in massive binaries. Our methodology consists in analyzing JVLA observations of WR 133 at different epochs to search for compelling evidence for a phase-locked variation attributable to synchrotron emission produced in the colliding-wind region. New data obtained during two orbits reveal a steady and thermal emission spectrum, in apparent contradiction with the previous detection of non-thermal emission. The thermal nature of the radio spectrum along the 112.4-d orbit is supported by the strong free–free absorption by the dense stellar winds, and shows that the simple binary scenario cannot explain the non-thermal emission reported previously. Alternatively, a triple system scenario with a wide, outer orbit would fit with the observational facts reported previously and in this paper, albeit no hint for the existence of a third component exists to date. The epoch-dependent nature of the identification of synchrotron radio emission in WR 133 emphasizes the issue of observational biases in the identification of PACWBs, that undoubtedly affect the present census of PACWB among colliding-wind binaries.

scholarly journals The impact of stellar rotation on the black hole mass-gap from pair-instability supernovae

2020 ◽  
Vol 640 ◽  
pp. L18 ◽  
Author(s):  
Pablo Marchant ◽  
Takashi J. Moriya
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
Compact Object ◽  
Iron Core ◽  
Lower Edge ◽  
Stellar Rotation ◽  
Transport Models ◽  
Mass Gap ◽  
Efficient Coupling ◽  
The Impact

Models of pair-instability supernovae (PISNe) predict a gap in black hole (BH) masses between ∼45 M⊙ and 120 M⊙, which is referred to as the upper BH mass-gap. With the advent of gravitational-wave astrophysics, it has become possible to test this prediction, and there is an important associated effort to understand which theoretical uncertainties modify the boundaries of this gap. In this work we study the impact of rotation on the hydrodynamics of PISNe, which leave no compact remnant, as well as the evolution of pulsational-PISNe (PPISNe), which undergo thermonuclear eruptions before forming a compact object. We perform simulations of nonrotating and rapidly rotating stripped helium stars in a metal-poor environment (Z⊙/50) in order to resolve the lower edge of the upper mass-gap. We find that the outcome of our simulations is dependent on the efficiency of angular momentum transport: models that include efficient coupling through the Spruit-Tayler dynamo shift the lower edge of the mass-gap upward by ∼4%, while simulations that do not include this effect shift it upward by ∼15%. From this, we expect that the lower edge of the upper mass-gap is dependent on BH spin, which can be tested as the number of observed BH mergers increases. Moreover, we show that stars undergoing PPISNe have extended envelopes (R ∼ 10 − 1000 R⊙) at iron-core collapse, making them promising progenitors for ultra-long gamma-ray bursts.

scholarly journals Microquasars and ULXS: Fossils of GRB Sources

2004 ◽  
Vol 194 ◽  
pp. 14-17 ◽  
Author(s):  
I. F. Mirabell
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Binary Systems ◽  
Gamma Ray ◽  
Massive Stars ◽  
Compact Objects ◽  
Primary Star ◽  
Long Duration ◽  
Supernova Explosions ◽  
Low Mass

AbstractGamma-ray bursts (GRBs) of long duration probably result from the core-collapse of massive stars in binary systems. After the collapse of the primary star the binary system may remain bound leaving a microquasar or ULX source as remnant. In this context, microquasars and ULXs are fossils of GRB sources and should contain physical and astrophysical clues on their GRB-source progenitors. Here I show that the identification of the birth place of microquasars can provide constrains on the progenitor stars of compact objects, and that the runaway velocity can be used to constrain the energy in the explosion of massive stars that leave neutron stars and black holes. The observations show that the neutron star binaries LS 5039, LSI +61°303 and the low-mass black hole GRO J1655-40 formed in energetic supernova explosions, whereas the black holes of larger masses (M ≥ 10 M⊙) in Cygnus X-l and GRS 1915+105 formed promptly, in the dark or in underluminous supornovao. The association with clusters of massive stars of the microquasar LSI +61°303 and the magnetars SGR 1806-20 and SGR 1900+14, suggest that very massive stars (M ≥ 50 M⊙) may -in some cases- leave neutron stars rather than black holes. The models of GRB sources of long duration have the same basic ingredients as microquasars and ULXs: compact objects with accretion disks and relativistic jets in binary systems. Therefore, the analogies between microquasars and AGN may be extended to the sources of GRBs.

scholarly journals Refining the origins of the gamma-ray binary 1FGL J1018.6–5856

2018 ◽  
Vol 619 ◽  
pp. A26 ◽  
Author(s):  
B. Marcote ◽  
M. Ribó ◽  
J. M. Paredes ◽  
M. Y. Mao ◽  
P. G. Edwards
Keyword(s):  
Radio Emission ◽  
Gamma Ray ◽  
Galactic Plane ◽  
Three Dimensional ◽  
Compact Object ◽  
High Energy ◽  
Physical Relation ◽  
Long Baseline ◽  
The Galaxy ◽  
Peculiar Motion

Context. Gamma-ray binaries are systems composed of a massive star and a compact object that exhibit emission from radio to very high energy gamma rays. They are ideal laboratories to study particle acceleration and a variety of physical processes that vary as a function of the orbital phase. Aims. We aim to study the radio emission of the gamma-ray binary 1FGL J1018.6–5856 to constrain the emitting region and determine the peculiar motion of the system within the Galaxy to clarify its origin. Methods. We analyzed an observation of 1FGL J1018.6–5856 with the Australian Long Baseline Array (LBA) at 8.4 GHz to obtain an accurate astrometry of the system and study its emission on milliarcsecond scales. We combined these data with the optical Gaia DR2 and UCAC4 catalogs to consolidate the astrometry information therein. Results. The gamma-ray binary 1FGL J1018.6–5856 shows compact radio emission (< 3 mas or ≲20 au at ∼6.4 kpc distance), implying a brightness temperature of ≳5.6 × 106 K, and confirming its nonthermal origin. We report consistent results between the proper motion reported by Gaia DR2 and the positions obtained from the Gaia DR2, UCAC4, and LBA data (spanning 20 yr in total). We also determined the distance to 1FGL J1018.6–5856 to be 6.4−0.7+1.7. Together with the radial velocity of the source we computed its three-dimensional (3D) proper and peculiar motion within the Galaxy. We obtained a peculiar motion of 1FGL J1018.6–5856 on its regional standard of rest (RSR) frame of |u| = 45−9+30, with the system moving away from the Galactic plane. In the simplest scenario of a symmetric stellar core collapse we estimate a mass loss of 4 ≲ ΔM ≲ 9 M⊙ during the creation of the compact object. Conclusions. 1FGL J1018.6–5856 exhibits compact radio emission similar to that detected in other gamma-ray binaries. We provide the first accurate peculiar motion estimations of the system and place it within the Galaxy. The obtained motion and distance excludes the physical relation of the binary source with the supernova remnant (SNR) G284.3−1.8.

scholarly journals The binary systems associated with short and long gamma-ray bursts and their detectability

2017 ◽  
Vol 26 (09) ◽  
pp. 1730016 ◽  
Author(s):  
Jorge A. Rueda ◽  
Y. Aimuratov ◽  
U. Barres de Almeida ◽  
L. Becerra ◽  
C. L. Bianco ◽  
...  
Keyword(s):  
Neutron Star ◽  
Gravitational Collapse ◽  
Binary Systems ◽  
Gamma Ray ◽  
Critical Mass ◽  
Compact Object ◽  
Gamma Ray Bursts ◽  
Black Hole Binaries ◽  
Long Duration

Short and long-duration gamma-ray bursts (GRBs) have been recently sub-classified into seven families according to the binary nature of their progenitors. For short GRBs, mergers of neutron star binaries (NS–NS) or neutron star-black hole binaries (NS-BH) are proposed. For long GRBs, the induced gravitational collapse (IGC) paradigm proposes a tight binary system composed of a carbon–oxygen core (CO[Formula: see text]) and a NS companion. The explosion of the CO[Formula: see text] as supernova (SN) triggers a hypercritical accretion process onto the NS companion which might reach the critical mass for the gravitational collapse to a BH. Thus, this process can lead either to a NS-BH or to NS–NS depending on whether or not the accretion is sufficient to induce the collapse of the NS into a BH. We shall discuss for the above compact object binaries: (1) the role of the NS structure and the equation-of-state on their final fate; (2) their occurrence rates as inferred from the X and gamma-ray observations; (3) the expected number of detections of their gravitational wave (GW) emission by the Advanced LIGO interferometer.

scholarly journals Tidal Interactions in Compact Binary Systems

1976 ◽  
Vol 73 ◽  
pp. 83-83
Author(s):  
J. C. Wheeler ◽  
M. Lecar
Keyword(s):  
Angular Velocity ◽  
Binary Systems ◽  
Compact Star ◽  
Compact Object ◽  
Major Axis ◽  
Semi Major Axis ◽  
Primary Star ◽  
Tidal Interactions ◽  
Single Orbit ◽  
The Difference

An analytic model has been constructed for the change of orbital elements because of tidal drag in a binary system where one of the components is compact (Lecar et al., 1976). The basic assumptions are (i) tides on the compact object are neglected (ii) only P2 deformations of the non-compact star are considered (iii) the lag angle is linearly proportional to the difference between the instantaneous orbital angular velocity and the spin angular velocity of the non-compact star (iv) the semi major axis a and eccentricity e do not change significantly in a single orbit. The results are exact solutions for a and ė as a function of e and the ratio of primary star to orbital angular velocity, Ω/ω.Tidal instability in this model is manifest by the dynamical inability to attain or sustain synchronism. An analysis to second order in e and first order in (Ω/ω−1) shows that the criterion for instability is the same as in the work of Counselman (1973), namely ma2 > I where m is the reduced mass and I the moment of inertia of the primary star. This criterion is shown to apply to eccentric orbits and is thus more general than the criterion derived from the energetics of circular orbits. Stable systems may overshoot the condition of synchronism before settling into the final circular synchronous orbit.

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