scholarly journals Detection of LIGO-Virgo binary black holes in the pair-instability mass gap

2021 ◽  
Vol 104 (8) ◽  
Author(s):  
B. O’Brien ◽  
M. Szczepańczyk ◽  
V. Gayathri ◽  
I. Bartos ◽  
G. Vedovato ◽  
...  
Keyword(s):  
Black Holes ◽  
Binary Black Holes ◽  
Mass Gap

scholarly journals Great Impostors: Extremely Compact, Merging Binary Neutron Stars in the Mass Gap Posing as Binary Black Holes

2020 ◽  
Vol 124 (7) ◽  
Author(s):  
Antonios Tsokaros ◽  
Milton Ruiz ◽  
Stuart L. Shapiro ◽  
Lunan Sun ◽  
Kōji Uryū
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Binary Black Holes ◽  
Mass Gap ◽  
Binary Neutron Stars

scholarly journals Binary black holes in the pair instability mass gap

2020 ◽  
Vol 497 (1) ◽  
pp. 1043-1049 ◽  
Author(s):  
Ugo N Di Carlo ◽  
Michela Mapelli ◽  
Yann Bouffanais ◽  
Nicola Giacobbo ◽  
Filippo Santoliquido ◽  
...  
Keyword(s):  
Black Holes ◽  
Formation Rate ◽  
Star Clusters ◽  
Design Sensitivity ◽  
Young Star ◽  
Binary Black Holes ◽  
Single Star ◽  
Mass Gap ◽  
Young Star Clusters ◽  
Stellar Mergers

ABSTRACT Pair instability (PI) and pulsational PI prevent the formation of black holes (BHs) with mass ≳60 M⊙ from single star evolution. Here, we investigate the possibility that BHs with mass in the PI gap form via stellar mergers and multiple stellar mergers, facilitated by dynamical encounters in young star clusters. We analyse 104 simulations, run with the direct N-body code nbody6++gpu coupled with the population synthesis code mobse. We find that up to ∼6 per cent of all simulated BHs have mass in the PI gap, depending on progenitor’s metallicity. This formation channel is strongly suppressed in metal-rich (Z = 0.02) star clusters because of stellar winds. BHs with mass in the PI gap are initially single BHs but can efficiently acquire companions through dynamical exchanges. We find that ∼21 per cent, 10 per cent, and 0.5 per cent of all binary BHs have at least one component in the PI mass gap at metallicity Z = 0.0002, 0.002, and 0.02, respectively. Based on the evolution of the cosmic star formation rate and metallicity, and under the assumption that all stars form in young star clusters, we predict that ∼5 per cent of all binary BH mergers detectable by advanced LIGO and Virgo at their design sensitivity have at least one component in the PI mass gap.

scholarly journals Polluting the Pair-instability Mass Gap for Binary Black Holes through Super-Eddington Accretion in Isolated Binaries

2020 ◽  
Vol 897 (1) ◽  
pp. 100 ◽  
Author(s):  
L. A. C. van Son ◽  
S. E. De Mink ◽  
F. S. Broekgaarden ◽  
M. Renzo ◽  
S. Justham ◽  
...  
Keyword(s):  
Black Holes ◽  
Binary Black Holes ◽  
Mass Gap

scholarly journals The mass gap, the spin gap, and the origin of merging binary black holes

2020 ◽  
Vol 102 (4) ◽  
Author(s):  
Vishal Baibhav ◽  
Davide Gerosa ◽  
Emanuele Berti ◽  
Kaze W. K. Wong ◽  
Thomas Helfer ◽  
...  
Keyword(s):  
Black Holes ◽  
Spin Gap ◽  
Binary Black Holes ◽  
Mass Gap

scholarly journals Merger Rate Density of Population III Binary Black Holes Below, Above, and in the Pair-instability Mass Gap

2021 ◽  
Vol 910 (1) ◽  
pp. 30
Author(s):  
Ataru Tanikawa ◽  
Hajime Susa ◽  
Takashi Yoshida ◽  
Alessandro A. Trani ◽  
Tomoya Kinugawa
Keyword(s):  
Black Holes ◽  
Binary Black Holes ◽  
Mass Gap ◽  
Merger Rate ◽  
Population Iii

scholarly journals Degeneracy between mass and peculiar acceleration for the double white dwarfs in the LISA band

2021 ◽  
Vol 502 (3) ◽  
pp. 4199-4209
Author(s):  
Zeyuan Xuan ◽  
Peng Peng ◽  
Xian Chen
Keyword(s):  
Black Holes ◽  
Analytical Method ◽  
Heliocentric Distance ◽  
Physical Parameters ◽  
Primordial Black Holes ◽  
Binary Black Holes ◽  
Mass Gap ◽  
Laser Interferometer Space Antenna ◽  
Measured Distance ◽  
Large Parameter Space

ABSTRACT Mass and distance are fundamental quantities to measure in gravitational wave (GW) astronomy. However, recent studies suggest that the measurement may be biased due to the acceleration of GW source. Here, we develop an analytical method to quantify such a bias induced by a tertiary star on a double white dwarf (DWD), since DWDs are the most common GW sources in the milli-Hertz band. We show that in a large parameter space the mass is degenerate with the peculiar acceleration, so that from the waveform we can only retrieve a mass of ${\cal M}(1+\Gamma)^{3/5}$, where ${\cal M}$ is the real chirp mass of the DWD and Γ is a dimensionless factor proportional to the peculiar acceleration. Based on our analytical method, we conduct mock observation of DWDs by the Laser Interferometer Space Antenna. We find that in about $9{{\ \rm per\ cent}}$ of the cases the measured chirp mass is biased by $(5-30){{\ \rm per\ cent}}$ due to the presence of a tertiary. Even more extreme biases are found in about a dozen DWDs and they may be misclassified as double neutron stars, binary black holes, DWDs undergoing mass transfer, or even binaries containing lower-mass-gap objects and primordial black holes. The bias in mass also affects the measured distance, resulting in a seemingly overdensity of DWDs within a heliocentric distance of 1 kpc as well as beyond 100 kpc. Our result highlights the necessity of modelling the astrophysical environments of GW sources to retrieve their correct physical parameters.

scholarly journals The missing link in gravitational-wave astronomy

2021 ◽  
Author(s):  
Manuel Arca Sedda ◽  
Christopher P. L. Berry ◽  
Karan Jani ◽  
Pau Amaro-Seoane ◽  
Pierre Auclair ◽  
...  
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Particle Physics ◽  
Cosmic Time ◽  
Compact Object ◽  
Stellar Mass ◽  
Wave Band ◽  
Binary Black Holes ◽  
Tests Of General Relativity ◽  
Binary Neutron Star

AbstractSince 2015 the gravitational-wave observations of LIGO and Virgo have transformed our understanding of compact-object binaries. In the years to come, ground-based gravitational-wave observatories such as LIGO, Virgo, and their successors will increase in sensitivity, discovering thousands of stellar-mass binaries. In the 2030s, the space-based LISA will provide gravitational-wave observations of massive black holes binaries. Between the $\sim 10$ ∼ 10 –103 Hz band of ground-based observatories and the $\sim 10^{-4}$ ∼ 1 0 − 4 –10− 1 Hz band of LISA lies the uncharted decihertz gravitational-wave band. We propose a Decihertz Observatory to study this frequency range, and to complement observations made by other detectors. Decihertz observatories are well suited to observation of intermediate-mass ($\sim 10^{2}$ ∼ 1 0 2 –104M⊙) black holes; they will be able to detect stellar-mass binaries days to years before they merge, providing early warning of nearby binary neutron star mergers and measurements of the eccentricity of binary black holes, and they will enable new tests of general relativity and the Standard Model of particle physics. Here we summarise how a Decihertz Observatory could provide unique insights into how black holes form and evolve across cosmic time, improve prospects for both multimessenger astronomy and multiband gravitational-wave astronomy, and enable new probes of gravity, particle physics and cosmology.

scholarly journals Predicting the broad-lines polarization emitted by supermassive binary black holes

2019 ◽  
Vol 623 ◽  
pp. A56 ◽  
Author(s):  
D. Savić ◽  
F. Marin ◽  
L. Č. Popović
Keyword(s):  
Black Holes ◽  
Emission Lines ◽  
Polarization Angle ◽  
Broad Line ◽  
Line Profiles ◽  
Binary Black Holes ◽  
True Nature ◽  
Line Shapes ◽  
Highly Sensitive ◽  
Balmer Lines

Context. Some Type-1 active galactic nuclei (AGN) show extremely asymmetric Balmer lines with the broad peak redshifted or blueshifted by thousands of km s−1. These AGN may be good candidates for supermassive binary black holes (SMBBHs). The complex line shapes can be due to the complex kinematics of the two broad line regions (BLRs). Therefore other methods should be applied to confirm the SMBBHs. One of them is spectropolarimetry. Aims. We rely on numerical modeling of the polarimetry of binary black holes systems, since polarimetry is highly sensitive to geometry, in order to find the specific influence of supermassive binary black hole (SMBBH) geometry and dynamics on polarized parameters across the broad line profiles. We apply our method to SMBBHs in which both components are assumed to be AGN with distances at the subparsec scale. Methods. We used a Monte Carlo radiative transfer code that simulates the geometry, dynamics, and emission pattern of a binary system where two black holes are getting increasingly close. Each gravitational well is accompanied by its own BLR and the whole system is surrounded by an accretion flow from the distant torus. We examined the emission line deformation and predicted the associated polarization that could be observed. Results. We modeled scattering-induced broad line polarization for various BLR geometries with complex kinematics. We find that the presence of SMBBHs can produce complex polarization angle profiles φ and strongly affect the polarized and unpolarized line profiles. Depending on the phase of the SMBBH, the resulting double-peaked emission lines either show red or blue peak dominance, or both the peaks can have the same intensity. In some cases, the whole line profile appears as a single Gaussian line, hiding the true nature of the source. Conclusions. Our results suggest that future observation with the high resolution spectropolarimetry of optical broad emission lines could play an important role in detecting subparsec SMBBHs.

scholarly journals Up-down instability of binary black holes in numerical relativity

2021 ◽  
Vol 103 (6) ◽  
Author(s):  
Vijay Varma ◽  
Matthew Mould ◽  
Davide Gerosa ◽  
Mark A. Scheel ◽  
Lawrence E. Kidder ◽  
...  
Keyword(s):  
Black Holes ◽  
Numerical Relativity ◽  
Binary Black Holes
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