Conveners
Transients and Gamma-Ray Bursts I: Gravitational Waves
- John Kirk (Max-Planck-Institut fuer Kernphysik)
Observation of gravitational-waves from compact binary mergers with Advanced LIGO have opened up the field of gravitational-wave astronomy. We'll discuss results from
the recent observing run of LIGO/Virgo and prospects for the future.
We talk about the released results from the searches of GBM data for electromagnetic counterparts to gravitational waves.
We use observations of the INTErnational Gamma-Ray Astrophysics
Laboratory (INTEGRAL) to search for gamma-ray and hard X-ray emission
associated with the gravitational wave events discovered during the
first and the second scientific runs of Advanced LIGO and Advanced
Virgo. The highly eccentric orbit of INTEGRAL ensures high duty
cycle, long-term stable background, and unobstructed view...
As the first detections of Gravitational Waves (GW) from the coalescence of compact objects were announced by LIGO and Virgo, a new era for astronomy began. Searches for electromagnetic (EM) counterparts of GW events are of fundamental importance, as their success will increase the confidence in the GW detection and will help characterize the system parameters. The Fermi Gamma-ray Space...
Binary neutron star mergers are considered to be the most favorable sources that produce electromagnetic (EM) signals associated with gravitational waves (GWs). They are also the likely progenitors of short duration gamma-ray bursts (GRBs). The brief gamma-ray emission (the “prompt” GRB emission) is produced by ultra-relativistic jets, as a result, this emission is strongly beamed over a small...
AT2017gfo is the first clearly detected kilonova, with comprehensive photometry and spectroscopy in the optical and NIR. I discuss this unique dataset in the context of previously published models and show fitting results using newly developed ones. I discuss inferred constraints on ejecta mass and composition in relation to simulations of neutron star mergers and theories for the origin of...
The prompt emission of the long, smooth, and single-pulsed gamma-ray burst, GRB 141028A, is analyzed under the guise of an external shock model. First, we fit the γ-ray spectrum with a two-component photon model, namely, synchrotron+blackbody, and then fit the recovered evolution of the synchrotron νFν peak to an analytic model derived considering the emission of a relativistic blast wave...
There is no conclusive model for the emission mechanism for Gamma-Ray Bursts (GRBs). The conventional synchrotron emission models have been shown to present difficulties in explaining the hard low-energy spectral slopes (e.g., Preece et al. 1998) and the sharp peak curvature (e.g., Yu et al. 2015) in the observed time-resolved spectra. On the contrary, thermal emission from the photosphere...
We numerically simulate the gamma-ray burst (GRB) afterglow emission with a one-zone time-dependent code. The temporal evolutions of the decelerating shocked shell and energy distributions of electrons and photons are consistently calculated. The photon spectrum and light curves for an observer are obtained taking into account the relativistic propagation of the shocked shell and the curvature...
The spectral width and sharpness of unfolded, observed GRB spectra have been presented as a new tool to infer physical properties about GRB emission via spectral fitting of empirical models. Following the tradition of the ’line-of-death’, the spectral width has been used to rule out synchrotron emission in a majority of GRBs. This claim is investigated via examination of both cataloged GRB...
Many of the properties of Gamma Ray Bursts (GRBs) remain poorly understood, particularly for short GRBs with durations less than ~2 sec. Fermi/LAT has shown that some GRBs emit at high-energy (100 MeV - ~100 GeV) gamma-rays with a hard (index of <2) spectrum. Atmospheric Cherenkov Telescopes (IACTs) could provide information on the possible emission at very-high-energy (VHE, >100 GeV)...
Gamma-ray bursts (GRBs) are the most energetic transients in the far Universe. Several thousands of GRBs have been observed so far but we could measure the distance of only a few hundreds. We studied the parameters of GRBs with available spectroscopic redshift in order to be able to estimate the redshift of those GRBs without a measured redshift. To calculate their distances we applied two...
The Fermi Flare Advocate (also known as Gamma-ray Sky Watcher) service provides for a quick look and review of the gamma-ray sky observed daily by the Fermi Large Area Telescope (LAT) through on-duty LAT Flare Advocates and high level software pipelines like the LAT Automatic Science Processing (ASP) and the Fermi All-sky Variability Analysis (FAVA). The FA-GSW service provides alerts and...
Classification of gamma-ray bursts (GRBs) into groups has been intensively studied by various statistical tests since 1998. It has been suggested that next to the groups of short/hard and long/soft GRBs there could be another class of intermediate durations. For the Swift/BAT database Veres et al. 2010 (ApJ, 725, 1955) it was found that the intermediate-duration bursts might be related to...
High-energy emission from Gamma-Ray Bursts is a powerful probe for extreme physics in these highly relativistic sources. Despite the advancements prompted by observations from the Fermi Large Area Telescope and the Fermi Gamma-Ray Burst Monitor, as well as other observatories, many questions remain open, especially on radiative processes and mechanisms. We present here the most extensive...
Gamma-ray bursts (GRBs) are characterised by a strong correlation between the instantaneous luminosity and the spectral peak energy within a burst. This correlation, which is known as the hardness-intensity correlation or the Golenetskii correlation, not only holds important clues to the physics of GRBs but is thought to have the potential to determine redshifts of bursts. In this paper, I use...
