black hole merger
Fr.: fusion de trous noirs
The collision of two → black holes in a → binary black hole system once they come so close that they cannot escape each other's gravity. They will merge in an extremely violent event to become one more massive black hole. The merger would produce tremendous energy and send massive ripples, called → gravitational waves, through the → space-time fabric of the Universe. Such an event (called GW150914) was first detected by the → Laser Interferometer Gravitational-Wave Observatory (LIGO) on September 14, 2015. The initial black hole masses were 36 and 29 Msun which gave a final black hole mass of 62 Msun, with 3 Msun radiated in gravitational waves. The event happened at a distance of 1.3 billion → light-years from Earth (Abbott et al., 2016, Phys. Rev. Lett. 116, 061102). Black hole merger is preceded by → inspiral and followed by → ringdown.
Fr.: fusion sans gaz
Fr.: fusion majeure
The → merging of two spiral galaxies with roughly equal masses colliding at appropriate angles. The dynamical friction is so efficient that the galaxies merge after only a few perigalactic passages.
1) tašké; 2) tašk
Fr.: fusion, coalescence
1) Any combination of two or more bodies into a single body. In particular, the formation
of a galaxy from the collision of two or more separate galaxies.
From → merge + -er (as in waiver).
Tašké; tašk, nouns from taškidan, → merge.
Fr.: processus de fusion
The process of collision between galaxies which leads to a single galaxy.
Fr.: arbre de coalescence
A method used in → numerical simulations for studying the growth and development of galaxies and → dark matter halos. Within the currently accepted ΛCDM cosmology, dark matter halos merge from small → clumps to ever larger structures. This merging history can be traced in simulations and stored in the form of merger trees. Merger trees are necessary because a galaxy may have more than one → progenitor at an early time.
Fr.: fusion mineure
The → merging in which one of the galaxies is significantly larger than the other (mass ratios above 10). The larger galaxy will often "swallow" the smaller satellite galaxy. The swallowed galaxy can trigger disk and nuclear star formation or activate a central core with shells that surround the predator.
Fr.: fusion mixte
Fr.: fusion avec gaz
A merger between → gas-rich galaxies. Wet mergers may lead to enhanced star formation, trigger → active galactic nuclei, and transform a → disk galaxy into an → elliptical galaxy. The larger the → redshift, the wetter mergers should be.