Downloads provided by UsageCounts
Abstract We report on the observations of gamma-ray burst (GRB) 190114C by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory. The prompt gamma-ray emission was detected by the Fermi GRB Monitor (GBM), the Fermi Large Area Telescope (LAT), and the Swift Burst Alert Telescope (BAT) and the long-lived afterglow emission was subsequently observed by the GBM, LAT, Swift X-ray Telescope (XRT), and Swift UV Optical Telescope. The early-time observations reveal multiple emission components that evolve independently, with a delayed power-law component that exhibits significant spectral attenuation above 40 MeV in the first few seconds of the burst. This power-law component transitions to a harder spectrum that is consistent with the afterglow emission observed by the XRT at later times. This afterglow component is clearly identifiable in the GBM and BAT light curves as a slowly fading emission component on which the rest of the prompt emission is superimposed. As a result, we are able to observe the transition from internal-shock- to external-shock-dominated emission. We find that the temporal and spectral evolution of the broadband afterglow emission can be well modeled as synchrotron emission from a forward shock propagating into a wind-like circumstellar environment. We estimate the initial bulk Lorentz factor using the observed high-energy spectral cutoff. Considering the onset of the afterglow component, we constrain the deceleration radius at which this forward shock begins to radiate in order to estimate the maximum synchrotron energy as a function of time. We find that even in the LAT energy range, there exist high-energy photons that are in tension with the theoretical maximum energy that can be achieved through synchrotron emission from a shock. These violations of the maximum synchrotron energy are further compounded by the detection of very high-energy (VHE) emission above 300 GeV by MAGIC concurrent with our observations. We conclude that the observations of VHE photons from GRB 190114C necessitates either an additional emission mechanism at very high energies that is hidden in the synchrotron component in the LAT energy range, an acceleration mechanism that imparts energy to the particles at a rate that is faster than the electron synchrotron energy-loss rate, or revisions of the fundamental assumptions used in estimating the maximum photon energy attainable through the synchrotron process.
Sjónaukar, TELESCOPE, Gammageislar, ddc:520, FOS: Physical sciences, DDC Classification::5 Naturwissenschaften und Mathematik :: 53 Physik :: 530 Physik, Neil Gehrels Swift Observatory, 530, Gamma ray bursts, GAMMA-RAY BURST, Fermi Gamma-ray Space Telescope, Fysik, Astrophysics - High Energy Astrophysical Phenomena; Gamma-ray bursts, SPECTRA, Gamma-ray burst, RELATIVISTIC TURBULENCE, LIGHT CURVES, High Energy Astrophysical Phenomena (astro-ph.HE), SYNCHROTRON, gamma-ray bursts, ddc:530, COMPONENT, 520, QC Physics / fizika, Physical Sciences, Gamma-ray bursts, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, Stjörnuskoðun, info:eu-repo/classification/ddc/520
Sjónaukar, TELESCOPE, Gammageislar, ddc:520, FOS: Physical sciences, DDC Classification::5 Naturwissenschaften und Mathematik :: 53 Physik :: 530 Physik, Neil Gehrels Swift Observatory, 530, Gamma ray bursts, GAMMA-RAY BURST, Fermi Gamma-ray Space Telescope, Fysik, Astrophysics - High Energy Astrophysical Phenomena; Gamma-ray bursts, SPECTRA, Gamma-ray burst, RELATIVISTIC TURBULENCE, LIGHT CURVES, High Energy Astrophysical Phenomena (astro-ph.HE), SYNCHROTRON, gamma-ray bursts, ddc:530, COMPONENT, 520, QC Physics / fizika, Physical Sciences, Gamma-ray bursts, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, Stjörnuskoðun, info:eu-repo/classification/ddc/520
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 66 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 1% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 1% |
| views | 30 | |
| downloads | 61 |

Views provided by UsageCounts
Downloads provided by UsageCounts