2 research outputs found
Searching for prompt signatures of nearby core-collapse supernovae by a joint analysis of neutrino and gravitational-wave data
We discuss the science motivations and prospects for a joint analysis of
gravitational-wave (GW) and low-energy neutrino data to search for prompt
signals from nearby supernovae (SNe). Both gravitational-wave and low-energy
neutrinos are expected to be produced in the innermost region of a
core-collapse supernova, and a search for coincident signals would probe the
processes which power a supernova explosion. It is estimated that the current
generation of neutrino and gravitational-wave detectors would be sensitive to
Galactic core-collapse supernovae, and would also be able to detect
electromagnetically dark SNe. A joint GW-neutrino search would enable
improvements to searches by way of lower detection thresholds, larger distance
range, better live-time coverage by a network of GW and neutrino detectors, and
increased significance of candidate detections. A close collaboration between
the GW and neutrino communities for such a search will thus go far toward
realizing a much sought-after astrophysics goal of detecting the next nearby
supernova.Comment: 10 pages, 3 figures. To appear in Class. Quantum Gra
Axisymmetric general relativistic simulations of the accretion-induced collapse of white dwarfs
The accretion-induced collapse (AIC) of a white dwarf may lead to the formation of a protoneutron star
and a collapse-driven supernova explosion. This process represents a path alternative to thermonuclear
disruption of accreting white dwarfs in type Ia supernovae. In the AIC scenario, the supernova explosion
energy is expected to be small and the resulting transient short-lived, making it hard to detect by
electromagnetic means alone. Neutrino and gravitational-wave (GW) observations may provide crucial
information necessary to reveal a potential AIC. Motivated by the need for systematic predictions of the
GW signature of AIC, we present results from an extensive set of general-relativistic AIC simulations
using a microphysical finite-temperature equation of state and an approximate treatment of deleptonization
during collapse. Investigating a set of 114 progenitor models in axisymmetric rotational equilibrium,
with a wide range of rotational configurations, temperatures and central densities, and resulting white
dwarf masses, we extend previous Newtonian studies and find that the GW signal has a generic shape akin
to what is known as a ‘‘type III’’ signal in the literature. Despite this reduction to a single type of
waveform, we show that the emitted GWs carry information that can be used to constrain the progenitor
and the postbounce rotation. We discuss the detectability of the emitted GWs, showing that the signal-tonoise
ratio for current or next-generation interferometer detectors could be high enough to detect such
events in our Galaxy. Furthermore, we contrast the GW signals of AIC and rotating massive star iron core
collapse and find that they can be distinguished, but only if the distance to the source is known and a
detailed reconstruction of the GW time series from detector data is possible. Some of our AIC models
form massive quasi-Keplerian accretion disks after bounce. The disk mass is very sensitive to progenitor
mass and angular momentum distribution. In rapidly differentially rotating models whose precollapse
masses are significantly larger than the Chandrasekhar mass, the resulting disk mass can be as large as
0:8M. Slowly and/or uniformly rotating models that are limited to masses near the Chandrasekhar
mass produce much smaller disks or no disk at all. Finally, we find that the postbounce cores of rapidly
spinning white dwarfs can reach sufficiently rapid rotation to develop a gravitorotational bar-mode
instability. Moreover, many of our models exhibit sufficiently rapid and differential rotation to become
subject to recently discovered low-E_(rot)/│W│-type dynamical instabilities