WFST等望远镜对千新星的探测能力与观测策略研究

Study of the detection capability and observation strategy of WFST-like telescope for kilonovae

本文模拟了红移z<0.2的双中子星并合源,并通过采用一个简单的千新星模型,计算了这些并合源所对应的千新星光变曲线.分别分析了大视场巡天望远镜(WFST)、大型综合巡天望远镜(LSST)和巡天空间望远镜(CSST)对这些模拟千新星的观测能力.发现WFST和LSST的最佳波段是g波段,它能观测到最多的源.此外,最佳双波段联合观测策略为:在最初的1.5天以内,通过g/r波段观测事件;在1.5天以后,通过r/i波段观测事件.对于CSST而言,通过采用深度无缝光谱来观测,发现GU波段能够在前1.5天观测到事件,GV波段能在前3.5天观测到事件,GI波段可观测事件的时间最长.同时我们发现,观测倾角对光变曲线的影响与质量比有关,对于质量比q<0.8的源,不同观测倾角对光变曲线的影响很小;但是对于质量比q>0.8的源,观测倾角对光变曲线的影响则非常明显.

We simulated the sources of binary neutron star mergers at redshift z<0.2 and calculated the light curves for the kilonovae associated with these mergers by adopting a simple kilonova model.We investigated the detectability of these simulated kilonovae using the wide field survey telescope(WFST),large synoptic survey telescope(LSST),and Chinese space station telescope(CSST).We determined that the best band for WFST and LSST is the g band,which could detect most sources.Moreover,the best two-band-observing strategies are observing events through the g/r band in the first 1.5 d and observing events via the r/i band after 1.5 d.For CSST,by observing via a deep slitless spectrum,we determined that GU band could detect the events in the first 1.5 d,the GV band could detect the events in the first 3.5 d,and the GI band could detect the events in the longest time.Meanwhile,we determined that the effect of viewing angle on light curve is related to mass ratio.For sources with a mass ratio q<0.8,the effect of viewing angle on the lightcurve is small.Conversely,for sources with a mass ratio q>0.8,the effect of viewing angle on the light curve is significant.