Related papers: Heavy element nucleosynthesis associated with a ga…
We present radiative transfer simulations for blue kilonovae hours after neutron star (NS) mergers by performing detailed opacity calculations for the first time. We calculate atomic structures and opacities of highly ionized elements (up…
The recent discovery of the neutron star merger and multi-messenger event GW170817 (also known as kilonova GRB170817A) provides an unprecedented laboratory in which to study these mysterious objects, as well as an opportunity to test…
The spectral features in the optical/near-infrared counterparts of neutron star mergers (kilonovae, KNe), evolve dramatically on hour timescales. To examine the spectral evolution we compile a temporal series complete at all observed epochs…
Direct detection of gravitational waves (GW) on Aug. 17, 2017, propagating from a binary neutron star merger, opened the era of multimessenger astronomy. The ejected material from neutron star mergers, or kilonova, is a good candidate for…
We study the radioactively-powered transients produced by accretion disk winds following a compact object merger. Starting with the outflows generated in two-dimensional hydrodynamical disk models, we use wavelength-dependent radiative…
Binary neutron star mergers and neutron star-black hole mergers are multi-messenger sources that can be detected in gravitational waves and in electromagnetic radiation. The low electron fraction of neutron star merger ejecta favors the…
Observations of metal-poor stars indicate that at least two different nucleosynthesis sites contribute to the production of r-process elements. One site is responsible for the production of light r-process elements Z<~50 while the other…
The existence of a secondary (in addition to compact object mergers) source of heavy element ($r$-process) nucleosynthesis, the core-collapse of rapidly-rotating and highly-magnetized massive stars, has been suggested by both simulations…
GW170817 was the first detection of a binary neutron star merger via gravitational waves. The event was observed over a wide range of the electromagnetic spectrum, revealing a thermal kilonova dominating the optical signal during the first…
In kilonovae, freshly-synthesized $r$-process elements imprint features on optical spectra, as observed in AT2017gfo, the counterpart to the GW170817 binary neutron star merger. However, measuring the $r$-process compositions of the merger…
The contemporaneous detection of gravitational waves and gamma rays from the GW170817/GRB 170817A, followed by kilonova emission a day after, confirmed compact binary neutron-star mergers as progenitors of short-duration gamma-ray bursts…
The historic observations of the neutron star merger GW170817 advanced our understanding of r-process nucleosynthesis and the equation of state (EOS) of neutron rich matter. Simple neutrino physics suggests that supernovae are not the site…
Observations of the kilonova from a neutron star merger event GW170817 opened a way to directly study r-process nucleosynthesis by neutron star mergers. It is, however, challenging to identify the individual elements in the kilonova spectra…
Compact object mergers can produce a thermal electromagnetic counterpart (a "kilonova") powered by the decay of freshly synthesized radioactive isotopes. The luminosity of kilonova light curves depends on the efficiency with which…
The 2017 detection of a kilonova coincident with gravitational-wave emission has identified neutron star mergers as the major source of the heaviest elements, and dramatically constrained alternative theories of gravity. Observing a…
The extremely rapid evolution of kilonovae results in spectra that change on an hourly basis. These spectra are key to understanding the processes occurring within the event, but this rapid evolution is an unfamiliar domain compared to…
On 17 August 2017, a gravitational wave event (GW170817) and an associated short gamma-ray burst (GRB 170817A) from a binary neutron star merger had been detected. The followup optical/infrared observations also identified the…
Recently, several telescopes, including Swift-BAT, GBM, and LHAASO, have observed the ever highest-energy and long-duration gamma-rays from a gamma-ray burst named as GRB221009A (located at a red-shift of $z=0.151$) on October 9, 2022.…
The unprecedented optical and near-infrared lightcurves of the first electromagnetic counterpart to a gravitational wave source, GW170817, a binary neutron star merger, exhibited a strong evolution from blue to near-infrared (a so-called…
We report the discovery of a transient equivalent hydrogen column density with an absorption edge at ~3.8 kiloelectron volts in the spectrum of the prompt x-ray emission of gamma-ray burst (GRB) 990705. This feature can be satisfactorily…