Magnetically driven gamma-ray bursts/ Gamma-ray Burst: A Possible Site to Detect R-process Elements?/Nuclear collective excitations and r-process nucleosynthesis

Wednesday 12 Feb 2014, 11:00 → 12:30 Asia/Tokyo

RIBF Bldg. Room 203 (RIKEN Wako)

Date: Wednesday, February 12th, 11:00- Place: Room 203, RIBF building Title: Magnetically driven gamma-ray bursts Speaker: Dr. Maxim Barkov (ABB Lab) Abstract: The strong dependence of the neutrino annihilation mechanism on the mass accretion rate makes it difficult to explain the long-duration gamma-ray bursts (LGRBs) with duration in excess of 100 s as well as the precursors separated from the main gamma-ray pulse by few hundreds of seconds. Even more difficult is to explain the Swift observations of the shallow decay phase and X-ray flares, if they indeed indicate activity of the central engine for as long as 10^4 s. These data suggest that some other, most likely magnetic mechanisms have to be considered. Since the efficiency of magnetic mechanisms does not depend that much on the mass accretion rate, the magnetic models do not require the development of accretion disc within the first few seconds of the stellar collapse and hence do not require very rapidly rotating stellar cores at the pre-supernova (SN) state. This widens the range of potential LGRB progenitors. Our 2D GRMHD numerical simulations confirm the possibility of magnetically driven stellar explosions, but point towards the required magnetic flux on the BH horizon in excess of 10^28 G cm^2. Title: Gamma-ray Burst: A Possible Site to Detect R-process Elements? Speaker: Dr. Jirong Mao (ABB Lab) Abstract: In this talk, I will briefly introduce gamma-ray burst observation and related physics. In particular, I will present recent observation of short GRB 130603B, which shows a possible detection of r-process. Title: Nuclear collective excitations and r-process nucleosynthesis Speaker: Dr. Haozhao Liang (TNP Lab) Abstract: In this talk, I will start from a brief introduction of nuclear collective excitations, and then discuss their roles in the r-process as an example of interdisciplinary applications in nuclear astrophysics.