scholarly journals Weighing in on black hole binaries with bpass: LB-1 does not contain a 70 M⊙ black hole

2020 ◽  
Vol 495 (3) ◽  
pp. 2786-2795 ◽  
Author(s):  
J J Eldridge ◽  
E R Stanway ◽  
K Breivik ◽  
A R Casey ◽  
D T H Steeghs ◽  
...  
Keyword(s):  
Black Hole ◽  
Binary System ◽  
Current Understanding ◽  
Stellar Winds ◽  
Population Synthesis ◽  
Distance Determination ◽  
Black Hole Binaries ◽  
Binary Evolution

ABSTRACT The recent identification of a candidate very massive (70 M⊙) black hole (BH) is at odds with our current understanding of stellar winds and pair-instability supernovae. We investigate alternate explanations for this system by searching the bpass v2.2 stellar and population synthesis models for those that match the observed properties of the system. We find binary evolution models that match the LB-1 system, at the reported Gaia distance, with more moderate BH masses of 4–7 M⊙. We also examine the suggestion that the binary motion may have led to an incorrect distance determination by Gaia. We find that the Gaia distance is accurate and that the binary system is consistent with the observation at this distance. Consequently, it is highly improbable that the BH in this system has the extreme mass originally suggested. Instead, it is more likely to be representative of the typical BH binary population expected in our Galaxy.

scholarly journals Prospects for the Discovery of Black Hole Binaries without Mass Accretion with Gaia

2016 ◽  
Vol 12 (S324) ◽  
pp. 41-42
Author(s):  
Norita Kawanaka ◽  
Masaki Yamaguchi ◽  
Tsvi Piran ◽  
Tomasz Bulik
Keyword(s):  
Mass Transfer ◽  
Black Holes ◽  
Black Hole ◽  
Orbital Period ◽  
Proper Motion ◽  
Binary Systems ◽  
Evolution Model ◽  
Black Hole Binaries ◽  
Black Hole Binary ◽  
Binary Evolution

AbstractWe study the prospect for Gaia to detect black hole binary systems without the mass transfer from their companion stars. Gaia will be able to discover Galactic black holes without mass accretion by detecting the proper motion of their companion stars. We evaluate the number of such black hole binaries which have the orbital period short enough to be detected by Gaia during its operation, taking into account the binary evolution model.

scholarly journals Contamination of RR Lyrae stars from Binary Evolution Pulsators

2015 ◽  
Vol 5 (1) ◽  
pp. 24-28
Author(s):  
P. Karczmarek
Keyword(s):  
Mass Transfer ◽  
Binary System ◽  
Synthesis Method ◽  
Population Synthesis ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Low Mass ◽  
Binary Evolution ◽  
Lyrae Stars ◽  
Range Of Values

A Binary Evolution Pulsator (BEP) is a low-mass (0.26 𝔐☉) member of a binary system, which pulsates as a result of a former mass transfer to its companion. The BEP mimics RR Lyrae-type pulsations, but has completely different internal structure and evolution history. Although there is only one known BEP (OGLE-BLG-RRLYR-02792), it has been estimated that approximately 0.2% of objects classified as RR Lyrae stars can be undetected Binary Evolution Pulsators. In the present work, this contamination value is re-evaluated using the population synthesis method. The output falls inside a range of values dependent on tuning the parameters in the StarTrack code, and varies from 0.06% to 0.43%.

scholarly journals Origin of spin–orbit misalignments: the microblazar V4641 Sgr

2020 ◽  
Vol 495 (2) ◽  
pp. 2179-2204 ◽  
Author(s):  
Greg Salvesen ◽  
Supavit Pokawanvit
Keyword(s):  
Black Hole ◽  
Binary System ◽  
Compact Object ◽  
Alternative Interpretation ◽  
Spin Orbit ◽  
Population Synthesis ◽  
Common Envelope ◽  
Black Hole Spin ◽  
Relativistic Jet ◽  
Jet Axis

ABSTRACT Of the known microquasars, V4641 Sgr boasts the most severe lower limit (>52°) on the misalignment angle between the relativistic jet axis and the binary orbital angular momentum. Assuming the jet and black hole spin axes coincide, we attempt to explain the origin of this extreme spin–orbit misalignment with a natal kick model, whereby an aligned binary system becomes misaligned by a supernova kick imparted to the newborn black hole. The model inputs are the kick velocity distribution, which we measure customized to V4641 Sgr, and the immediate pre/post-supernova binary system parameters. Using a grid of binary stellar evolution models, we determine post-supernova configurations that evolve to become consistent with V4641 Sgr today and obtain the corresponding pre-supernova configurations by using standard prescriptions for common envelope evolution. Using each of these potential progenitor system parameter sets as inputs, we find that a natal kick struggles to explain the origin of the V4641 Sgr spin–orbit misalignment. Consequently, we conclude that evolutionary pathways involving a standard common envelope phase followed by a supernova kick are highly unlikely for V4641 Sgr. An alternative interpretation is that the jet axis does not reliably trace the black hole spin axis. Our results raise concerns about compact object merger statistics gleaned from binary population synthesis models, which rely on unverified prescriptions for common envelope evolution and natal kicks. We also challenge the spin–orbit alignment assumption routinely invoked to measure black hole spin magnitudes.

scholarly journals Cosmic archaeology with massive stellar black hole binaries

2020 ◽  
Vol 495 (1) ◽  
pp. L81-L85 ◽  
Author(s):  
L Graziani ◽  
R Schneider ◽  
S Marassi ◽  
W Del Pozzo ◽  
M Mapelli ◽  
...  
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
Gravitational Wave ◽  
Galaxy Formation ◽  
Population Synthesis ◽  
Formation Model ◽  
Black Hole Binaries ◽  
The Galaxy ◽  
Low Metallicity ◽  
Black Hole Masses

ABSTRACT The existence of massive stellar black hole binaries (MBHBs), with primary black hole masses $\ge 31 \, \mathrm{ M}_\odot$, was proven by the detection of the gravitational wave (GW) event GW150914 during the first LIGO/Virgo observing run (O1), and successively confirmed by seven additional GW signals discovered in the O1 and O2 data. By adopting the galaxy formation model gamesh coupled with binary population synthesis (BPS) calculations, here we investigate the origin of these MBHBs by selecting simulated binaries compatible in mass and coalescence redshifts. We find that their cosmic birth rates peak in the redshift range 6.5 ≤ z ≤ 10, regardless of the adopted BPS. These MBHBs are then old systems forming in low-metallicity ($Z \sim [0.01\!-\!0.1] \, Z_{\odot }$), low-stellar-mass galaxies, before the end of cosmic reionization, i.e. significantly beyond the peak of cosmic star formation. GW signals generated by coalescing MBHBs open up new possibilities to probe the nature of stellar populations in remote galaxies, at present too faint to be detected by available electromagnetic facilities.

scholarly journals The origin of spin in binary black holes

2020 ◽  
Vol 635 ◽  
pp. A97 ◽  
Author(s):  
Simone S. Bavera ◽  
Tassos Fragos ◽  
Ying Qin ◽  
Emmanouil Zapartas ◽  
Coenraad J. Neijssel ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Scientific Progress ◽  
Hybrid Technique ◽  
Population Synthesis ◽  
Binary Black Holes ◽  
Common Envelope ◽  
The Common ◽  
Binary Evolution

Context. After years of scientific progress, the origin of stellar binary black holes is still a great mystery. Several formation channels for merging black holes have been proposed in the literature. As more merger detections are expected with future gravitational-wave observations, population synthesis studies can help to distinguish between them. Aims. We study the formation of coalescing binary black holes via the evolution of isolated field binaries that go through the common envelope phase in order to obtain the combined distributions of observables such as black-hole spins, masses and cosmological redshifts of mergers. Methods. To achieve this aim, we used a hybrid technique that combines the parametric binary population synthesis code COMPAS with detailed binary evolution simulations performed with the MESA code. We then convolved our binary evolution calculations with the redshift- and metallicity-dependent star-formation rate and the selection effects of gravitational-wave detectors to obtain predictions of observable properties. Results. By assuming efficient angular momentum transport, we are able to present a model that is capable of simultaneously predicting the following three main gravitational-wave observables: the effective inspiral spin parameter χeff, the chirp mass Mchirp and the cosmological redshift of merger zmerger. We find an excellent agreement between our model and the ten events from the first two advanced detector observing runs. We make predictions for the third observing run O3 and for Advanced LIGO design sensitivity. We expect approximately 80% of events with χeff <  0.1, while the remaining 20% of events with χeff ≥ 0.1 are split into ∼10% with Mchirp <  15 M⊙ and ∼10% with Mchirp ≥ 15 M⊙. Moreover, we find that Mchirp and χeff distributions are very weakly dependent on the detector sensitivity. Conclusions. The favorable comparison of the existing LIGO/Virgo observations with our model predictions gives support to the idea that the majority, if not all of the observed mergers, originate from the evolution of isolated binaries. The first-born black hole has negligible spin because it lost its envelope after it expanded to become a giant star, while the spin of the second-born black hole is determined by the tidal spin up of its naked helium star progenitor by the first-born black hole companion after the binary finished the common-envelope phase.

scholarly journals On the nature of the “radio quiet” black hole binaries

2010 ◽  
Vol 6 (S275) ◽  
pp. 265-269
Author(s):  
Paolo Soleri ◽  
Rob Fender
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Binary System ◽  
Lorentz Factor ◽  
Energy Output ◽  
X Ray ◽  
Black Hole Binaries ◽  
Accretion Flows ◽  
Empirical Relations ◽  
Many Sources

AbstractThe accretion/ejection coupling in accreting black hole binaries has been described by empirical relations between the X-ray/radio and X-ray/optical-infrared luminosities. These correlations were initially supposed to be universal. However, recently many sources have been found to produce jets that, given certain accretion-powered luminosities, are fainter than expected from the correlations. This shows that black holes with similar accretion flows can produce a broad range of outflows in power Here we discuss whether typical parameters of the binary system, as well as the properties of the outburst, produce any effect on the energy output in the jet. We also define a jet-toy model in which the bulk Lorentz factor becomes larger than ~1 above ~0.1% of the Eddington luminosity. We finally compare the “radio quiet” black holes with the neutron stars.

scholarly journals Formation of counter-rotating and highly eccentric massive black hole binaries in galaxy mergers

2021 ◽  
Vol 503 (1) ◽  
pp. 498-510
Author(s):  
Imran Tariq Nasim ◽  
Cristobal Petrovich ◽  
Adam Nasim ◽  
Fani Dosopoulou ◽  
Fabio Antonini
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Dynamical Evolution ◽  
Orbital Plane ◽  
Equal Mass ◽  
Galaxy Mergers ◽  
High Eccentricity ◽  
Massive Black Hole ◽  
Black Hole Binaries ◽  
Binary Evolution

ABSTRACT Supermassive black hole (SMBH) binaries represent the main target for missions such as the Laser Interferometer Space Antenna and Pulsar Timing Arrays. The understanding of their dynamical evolution prior to coalescence is therefore crucial to improving detection strategies and for the astrophysical interpretation of the gravitational wave data. In this paper, we use high-resolution N-body simulations to model the merger of two equal-mass galaxies hosting a central SMBH. In our models, all binaries are initially prograde with respect to the galaxy sense of rotation. But, binaries that form with a high eccentricity, e ≳ 0.7, quickly reverse their sense of rotation and become almost perfectly retrograde at the moment of binary formation. The evolution of these binaries proceeds towards larger eccentricities, as expected for a binary hardening in a counter-rotating stellar distribution. Binaries that form with lower eccentricities remain prograde and at comparatively low eccentricities. We study the origin of the orbital flip by using an analytical model that describes the early stages of binary evolution. This model indicates that the orbital plane flip is due to the torque from the triaxial background mass distribution that naturally arises from the galactic merger process. Our results imply the existence of a population of SMBH binaries with a high eccentricity and could have significant implications for the detection of the gravitational wave signal emitted by these systems.

scholarly journals Evolution of binary stars and its implications for evolutionary population synthesis

2009 ◽  
Vol 5 (S262) ◽  
pp. 44-47
Author(s):  
Z. Han ◽  
X. Chen ◽  
F. Zhang ◽  
Ph. Podsiadlowski
Keyword(s):  
Binary System ◽  
Binary Stars ◽  
Elliptical Galaxies ◽  
Close Binary System ◽  
Close Binary ◽  
Population Synthesis ◽  
Blue Stragglers ◽  
Uv Excess ◽  
Hot Subdwarfs ◽  
Binary Evolution

AbstractMost stars are members of binaries, and the evolution of a star in a close binary system differs from that of an ioslated star due to the proximity of its companion star. The components in a binary system interact in many ways and binary evolution leads to the formation of many peculiar stars, including blue stragglers and hot subdwarfs. We will discuss binary evolution and the formation of blue stragglers and hot subdwarfs, and show that those hot objects are important in the study of evolutionary population synthesis (EPS), and conclude that binary interactions should be included in the study of EPS. Indeed, binary interactions make a stellar population younger (hotter), and the far-ultraviolet (UV) excess in elliptical galaxies is shown to be most likely resulted from binary interactions. This has major implications for understanding the evolution of the far-UV excess and elliptical galaxies in general. In particular, it implies that the far-UV excess is not a sign of age, as had been postulated prviously and predicts that it should not be strongly dependent on the metallicity of the population, but exists universally from dwarf ellipticals to giant ellipticals.

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