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CCNU Made New Advances in Astrophysical Rresearch on Observational Limit of Jet Structure of Gamma-Ray Bursts


Revision:Chen Jialong; Xiao YaoDate:2020/10/31


Gamma-ray bursts (GRBs) is the most intense explosion phenomenon in the universe and the radiation of GRBs mainly come from a pair of relativistic jets. However, there exists a key scientific problem of lacking knowledge on the productive process and physical structures jets in GRBs research.

Prof. Yu Yunwei from the School of Physics of CCNU and associate Prof. Tan Weiwei from Hubei University of Education have made some new breakthroughs. The joint observation of GW170817 and GRB 170817A indicated that short gamma-ray bursts (SGRBs) can originate from binary neutron star mergers. Moreover, some SGRBs could be detected off axis, while the SGRBs jets are highly structured. Then, by assuming a universal angular distribution of the jet emission for all SGRBs, we reproduce the flux and redshift distributions of the cosmological SGRBs detected by Swift and Fermi. For self-consistency, this angular distribution is simultaneously constrained by the luminosity and event rate of GRB 170817A. As a result, it is found that the universal jet structure of SGRBs could approximately have a two-Gaussian profile. Meanwhile, the intrinsic luminosity function (LF) of the on-axis emission of the jets can be simply described by a single power law with a low-luminosity exponential cutoff. The usually discovered broken-power-law apparent LF for relatively high luminosities can naturally result from the coupling of the intrinsic LF with the angular distribution of the jet emission, as the viewing angles to the SGRBs are arbitrarily distributed. The study was published recently on Astrophysical Journal (https://iopscience.iop.org/article/10.3847/1538-4357/abb404).

Meanwhile, Prof. Yu Yunwei points out that gravitational waves memory could enable us directly to “see” the production and propagation of the GRBs through the gravitational waves spectrum, which provides a potential way to change the current situation of indirectly inferencing the structure of jets only by electromagnetic wave observation. This study was published on Astrophysical Journal (https://iopscience.iop.org/article/10.3847/1538-4357/ab93cc).


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