Search results for " black"
showing 10 items of 317 documents
Search for eccentric binary black hole mergers with advanced LIGO and advanced Virgo during their first and second observing runs
2019
When formed through dynamical interactions, stellar-mass binary black holes may retain eccentric orbits ($e>0.1$ at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically-formed binaries from isolated binary black hole mergers. Current template-based gravitational-wave searches do not use waveform models associated to eccentric orbits, rendering the search less efficient to eccentric binary systems. Here we present results of a search for binary black hole mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. The search uses min…
Evaporation of Near-Extremal Reissner-Nordström Black Holes
2000
The formation of near-extremal Reissner-Nordstrom black holes in the S-wave approximation can be described, near the event horizon, by an effective solvable model. The corresponding one-loop quantum theory remains solvable and allows to follow analytically the evaporation process which is shown to require an infinite amount of time.
New horizons for fundamental physics with LISA
2022
K. G. Arun et al.
Accretion disks around binary black holes of unequal mass: General relativistic MHD simulations of postdecoupling and merger
2014
We report results from simulations in general relativity of magnetized disks accreting onto merging black hole binaries, starting from relaxed disk initial data. The simulations feature an effective, rapid radiative cooling scheme as a limiting case of future treatments with radiative transfer. Here we evolve the systems after binary-disk decoupling through inspiral and merger, and analyze the dependence on the binary mass ratio with $q\ensuremath{\equiv}{m}_{\text{bh}}/{M}_{\mathrm{BH}}=1,1/2$, and $1/4$. We find that the luminosity associated with local cooling is larger than the luminosity associated with matter kinetic outflows, while the electromagnetic (Poynting) luminosity associated…
Magnetorotational Collapse of Supermassive Stars: Black Hole Formation, Gravitational Waves and Jets
2017
We perform MHD simulations in full GR of uniformly rotating stars that are marginally unstable to collapse. Our simulations model the direct collapse of supermassive stars (SMSs) to seed black holes (BHs) that can grow to become the supermassive BHs at the centers of quasars and AGNs. They also crudely model the collapse of massive Pop III stars to BHs, which could power a fraction of distant, long gamma-ray bursts (GRBs). The initial stellar models we adopt are $\Gamma = 4/3$ polytropes seeded with a dynamically unimportant dipole magnetic field (B field). We treat initial B-field configurations either confined to the stellar interior or extending out from the interior into the stellar ext…
Simulating the magnetorotational collapse of supermassive stars: Incorporating gas pressure perturbations and different rotation profiles
2018
Collapsing supermassive stars (SMSs) with masses $M \gtrsim 10^{4-6}M_\odot$ have long been speculated to be the seeds that can grow and become supermassive black holes (SMBHs). We previously performed GRMHD simulations of marginally stable magnetized $\Gamma = 4/3$ polytropes uniformly rotating at the mass-shedding limit to model the direct collapse of SMSs. These configurations are supported entirely by thermal radiation pressure and model SMSs with $M \gtrsim 10^{6}M_\odot$. We found that around $90\%$ of the initial stellar mass forms a spinning black hole (BH) surrounded by a massive, hot, magnetized torus, which eventually launches an incipient jet. Here we perform GRMHD simulations o…
Multifrequency Studies of the Peculiar Quasar 4C +21.35 during the 2010 Flaring Activity
2014
著者人数: 290名
A search for point sources of EeV neutrons
2012
A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from −90◦ to +15◦ in declination using four different energy ranges above 1 EeV (1018 eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultrahigh energy cosmic rays in the Galaxy.
GW190521: A Binary Black Hole Merger with a Total Mass of 150 M⊙
2020
LIGO Scientific Collaboration and Virgo Collaboration: et al.
All-sky search for short gravitational-wave bursts in the second Advanced LIGO and Advanced Virgo run
2019
We present the results of a search for short-duration gravitational-wave transients in the data from the second observing run of Advanced LIGO and Advanced Virgo. We search for gravitational-wave transients with a duration of milliseconds to approximately one second in the 32-4096 Hz frequency band with minimal assumptions about the signal properties, thus targeting a wide variety of sources. We also perform a matched-filter search for gravitational-wave transients from cosmic string cusps for which the waveform is well-modeled. The unmodeled search detected gravitational waves from several binary black hole mergers which have been identified by previous analyses. No other significant event…