The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform
I Arcavi - One of the best experts on this subject based on the ideXlab platform.
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optical emission from a kilonova following a gravitational wave Detected Neutron star merger
Nature, 2017Co-Authors: I Arcavi, G Hosseinzadeh, Andrew D Howell, C Mccully, Dovi Poznanski, Daniel KasenAbstract:The merger of two Neutron stars has been predicted to produce an optical–infrared transient (lasting a few days) known as a ‘kilonova’, powered by the radioactive decay of Neutron-rich species synthesized in the merger. Evidence that short γ-ray bursts also arise from Neutron-star mergers has been accumulating. In models of such mergers, a small amount of mass (10^(−4)–10^(−2) solar masses) with a low electron fraction is ejected at high velocities (0.1–0.3 times light speed) or carried out by winds from an accretion disk formed around the newly merged object. This mass is expected to undergo rapid Neutron capture (r-process) nucleosynthesis, leading to the formation of radioactive elements that release energy as they decay, powering an electromagnetic transient. A large uncertainty in the composition of the newly synthesized material leads to various expected colours, durations and luminosities for such transients. Observational evidence for kilonovae has so far been inconclusive because it was based on cases of moderate excess emission Detected in the afterglows of γ-ray bursts. Here we report optical to near-infrared observations of a transient coincident with the detection of the gravitational-wave signature of a binary Neutron-star merger and with a low-luminosity short-duration γ-ray burst20. Our observations, taken roughly every eight hours over a few days following the gravitational-wave trigger, reveal an initial blue excess, with fast optical fading and reddening. Using numerical models, we conclude that our data are broadly consistent with a light curve powered by a few hundredths of a solar mass of low-opacity material corresponding to lanthanide-poor (a fraction of 10^(−4.5) by mass) ejecta.
S Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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reverse shocks in the relativistic outflows of gravitational wave Detected Neutron star binary mergers
Monthly Notices of the Royal Astronomical Society, 2019Co-Authors: G P Lamb, S KobayashiAbstract:The afterglows to gamma-ray bursts (GRBs) are due to synchrotron emission from shocks generated as an ultrarelativistic outflow decelerates. A forward and a reverse shock will form, however, where emission from the forward shock is well studied as a potential counterpart to gravitational wave-Detected Neutron star mergers the reverse shock has been neglected. Here, we show how the reverse shock contributes to the afterglow from an off-axis and structured outflow. The off-axis reverse shock will appear as a brightening feature in the rising afterglow at radio frequencies. For bursts at ∼100 Mpc, the system should be inclined ≲20° for the reverse shock to be observable at ∼0.1–10 d post-merger. For structured outflows, enhancement of the reverse shock emission by a strong magnetic field within the outflow is required for the emission to dominate the afterglow at early times. Early radio photometry of the afterglow could reveal the presence of a strong magnetic field associated with the central engine.
Daniel Kasen - One of the best experts on this subject based on the ideXlab platform.
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optical emission from a kilonova following a gravitational wave Detected Neutron star merger
Nature, 2017Co-Authors: I Arcavi, G Hosseinzadeh, Andrew D Howell, C Mccully, Dovi Poznanski, Daniel KasenAbstract:The merger of two Neutron stars has been predicted to produce an optical–infrared transient (lasting a few days) known as a ‘kilonova’, powered by the radioactive decay of Neutron-rich species synthesized in the merger. Evidence that short γ-ray bursts also arise from Neutron-star mergers has been accumulating. In models of such mergers, a small amount of mass (10^(−4)–10^(−2) solar masses) with a low electron fraction is ejected at high velocities (0.1–0.3 times light speed) or carried out by winds from an accretion disk formed around the newly merged object. This mass is expected to undergo rapid Neutron capture (r-process) nucleosynthesis, leading to the formation of radioactive elements that release energy as they decay, powering an electromagnetic transient. A large uncertainty in the composition of the newly synthesized material leads to various expected colours, durations and luminosities for such transients. Observational evidence for kilonovae has so far been inconclusive because it was based on cases of moderate excess emission Detected in the afterglows of γ-ray bursts. Here we report optical to near-infrared observations of a transient coincident with the detection of the gravitational-wave signature of a binary Neutron-star merger and with a low-luminosity short-duration γ-ray burst20. Our observations, taken roughly every eight hours over a few days following the gravitational-wave trigger, reveal an initial blue excess, with fast optical fading and reddening. Using numerical models, we conclude that our data are broadly consistent with a light curve powered by a few hundredths of a solar mass of low-opacity material corresponding to lanthanide-poor (a fraction of 10^(−4.5) by mass) ejecta.
C Mccully - One of the best experts on this subject based on the ideXlab platform.
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optical emission from a kilonova following a gravitational wave Detected Neutron star merger
Nature, 2017Co-Authors: I Arcavi, G Hosseinzadeh, Andrew D Howell, C Mccully, Dovi Poznanski, Daniel KasenAbstract:The merger of two Neutron stars has been predicted to produce an optical–infrared transient (lasting a few days) known as a ‘kilonova’, powered by the radioactive decay of Neutron-rich species synthesized in the merger. Evidence that short γ-ray bursts also arise from Neutron-star mergers has been accumulating. In models of such mergers, a small amount of mass (10^(−4)–10^(−2) solar masses) with a low electron fraction is ejected at high velocities (0.1–0.3 times light speed) or carried out by winds from an accretion disk formed around the newly merged object. This mass is expected to undergo rapid Neutron capture (r-process) nucleosynthesis, leading to the formation of radioactive elements that release energy as they decay, powering an electromagnetic transient. A large uncertainty in the composition of the newly synthesized material leads to various expected colours, durations and luminosities for such transients. Observational evidence for kilonovae has so far been inconclusive because it was based on cases of moderate excess emission Detected in the afterglows of γ-ray bursts. Here we report optical to near-infrared observations of a transient coincident with the detection of the gravitational-wave signature of a binary Neutron-star merger and with a low-luminosity short-duration γ-ray burst20. Our observations, taken roughly every eight hours over a few days following the gravitational-wave trigger, reveal an initial blue excess, with fast optical fading and reddening. Using numerical models, we conclude that our data are broadly consistent with a light curve powered by a few hundredths of a solar mass of low-opacity material corresponding to lanthanide-poor (a fraction of 10^(−4.5) by mass) ejecta.
Andrew D Howell - One of the best experts on this subject based on the ideXlab platform.
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optical emission from a kilonova following a gravitational wave Detected Neutron star merger
Nature, 2017Co-Authors: I Arcavi, G Hosseinzadeh, Andrew D Howell, C Mccully, Dovi Poznanski, Daniel KasenAbstract:The merger of two Neutron stars has been predicted to produce an optical–infrared transient (lasting a few days) known as a ‘kilonova’, powered by the radioactive decay of Neutron-rich species synthesized in the merger. Evidence that short γ-ray bursts also arise from Neutron-star mergers has been accumulating. In models of such mergers, a small amount of mass (10^(−4)–10^(−2) solar masses) with a low electron fraction is ejected at high velocities (0.1–0.3 times light speed) or carried out by winds from an accretion disk formed around the newly merged object. This mass is expected to undergo rapid Neutron capture (r-process) nucleosynthesis, leading to the formation of radioactive elements that release energy as they decay, powering an electromagnetic transient. A large uncertainty in the composition of the newly synthesized material leads to various expected colours, durations and luminosities for such transients. Observational evidence for kilonovae has so far been inconclusive because it was based on cases of moderate excess emission Detected in the afterglows of γ-ray bursts. Here we report optical to near-infrared observations of a transient coincident with the detection of the gravitational-wave signature of a binary Neutron-star merger and with a low-luminosity short-duration γ-ray burst20. Our observations, taken roughly every eight hours over a few days following the gravitational-wave trigger, reveal an initial blue excess, with fast optical fading and reddening. Using numerical models, we conclude that our data are broadly consistent with a light curve powered by a few hundredths of a solar mass of low-opacity material corresponding to lanthanide-poor (a fraction of 10^(−4.5) by mass) ejecta.