English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In this work, we restudy the dependence of luminosity function and eventrates for different gamma-ray burst samples on the criteria of sample selectionand threshold effect. To compare with many previous studies, we have chosen twosamples including 88 and 118 long bursts with known redshift and peak flux over2.6 ph cm$^{-2}$ s$^{-1}$, from which 79 bursts are picked out to constituteour complete sample. It is found that the evolution of luminosity with redshiftcan be expressed by $L\propto(1+z)^k$ with a diverse $k$ relied more on thesample selection. Interestingly, the cumulative distributions of eithernon-evolving luminosities or redshifts are found to be also determined by thesample selection rather than the instrumental sensitivity. Nevertheless, thenon-evolving luminosities of our samples are similarly distributed with acomparable break luminosity of $L_0\sim10^{51}$ erg s$^{-1}$. Importantly, weverify with a K-S test that three cases of event rates for the two burstsamples evolve with redshift similarly except a small discrepancy due tosampling differences at low-redshift of $z<1$, in which all event rates show anexcess of Gaussian profile instead of monotonous decline no matter whether thesample is complete. Most importantly, it is found that the burst rates violatethe star formation rate at low redshift, while both of them are good inagreement with each other in the higher-redshift regions as many authorsdiscovered previously. Therefore, we predict that two types of long bursts arefavored in terms of their associations with both the star formation and thecosmic metallicity.

A Comparative Study of Luminosity Functions and Event Rate Densities of Long GRBs with Non-parametric Method