The "amplitude" parameter of Gamma-Ray Bursts and its implications for GRB classification

Traditionally gamma-ray bursts (GRBs) are classified in the $T_{90}$-hardness ratio two-dimensional plane into long/soft and short/hard GRBs. In this paper, we suggest to add the "amplitude" of GRB prompt emission as the third dimension as a complementary criterion to classify GRBs, especially those of short durations. We define three new parameters $f$, $f_{\rm eff}$ and $f_{\rm eff,z}$ as ratios between the measured/simulated peak flux of a GRB/pseudo-GRB and the flux background, and discuss the applications of these parameters to GRB classification. We systematically derive these parameters to find that most short GRBs are likely not "tip-of-iceberg" of long GRBs. However, one needs to be cautious if a short GRB has a relatively small $f$ (e.g. $f<1.5$), since the chance for an intrinsically long GRB to appear as a "disguised" short GRB is higher. Based on avaialble data, we quantify the probability of a disguised short GRB below a certain $f$ value is as $P (<f)\sim 0.78^{+0.71}_{-0.4} f^{-4.33\pm 1.84}$. By progressively "moving" a long GRB to higher redshifts through simulations, we also find that most long GRBs would show up as rest-frame short GRBs above a certain redshift.Comment: 11 pages, 14 figures. Accepted by MNRA

From cultural diversity to creative city: theoretical logic and practical exploration of the gourmet city

The construction of creative cities is an important choice for the current urban transformation and development. Taking the “city of gastronomy” of UNESCO creative cities network as the research object, this paper analyzes the impact of cultural diversity on creative cities. Based on the theoretical connotation of creative cities and the logical analysis of the relationship between cultural and creative industries and creative cities, this paper puts forward the theoretical basis for the construction of “food city”, and constructs the urban food creative system from four aspects: urban food culture, creative community, environment and atmosphere, investment and financing, and intellectual property protection. On this basis, combined with the group characteristics of the “food city” and the case of Yangzhou, this paper analyzes the practical process and key issues of creating the “food city”, and summarizes the experience and Enlightenment from the “food city” to the creative city