Late-time photometry of two nearby type II-P supernovae: 2004dj and 2004et

查看全文 作　　者：Tian-Meng [1,2,4]Zhang;Xiao-Feng [3,5]Wang;Xu [1]Zhou;Jun [1]Ma;Zhao-Ji [1]Jiang;Jiang-Hua [1]Wu;Zhen-Yu [1]Wu;Stephane [2]Basa 机构地区：[1]NationalAstronomicalObservatories, Chinese Academy of Sciences, Beijing 100012, China;;[2]Observatoire Astronomique de Marseille-Provence, 38, rue Fric Joliot-Curie, 13388 Marseille Cedex 13, France;[3]Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 100084, China;[4]Graduate University of Chinese Academy of Sciences, Beijing 100049, China;[5]Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA 出　　处：《Research in Astronomy and Astrophysics》索引2009年第9卷第7期,共8页 基　　金：supported by the Chinese National Natural Science Foundation through grants 10873016, 10803007, 10473012, 10573020, 10633020, 10603006 and 10673007;the National Basic Research Program of China (973 Program) No. 2007CB815403;the National Key Basic Research Science Foundation (NKBRSF TG199075402) ;Basic Research Funding at Tsinghua University (JCqn2005036) 摘　　要：We present late-time photometry for two bright type II-P supernovae (SNe) 2004dj and 2004et,extending over 400d after the explosion,which are measured with a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features. Although these two SNe II-P exhibit similar photometric evolution at earlier times,they diverge during the nebular phase. SN 2004dj shows a slow late-time decline rate with ~ 0.7 ± 0.1 mag (100d)-1 during the period ranging from t ≈ 200 300 d after the explosion,while SN 2004et shows a much faster decline rate at a comparable phase,e.g.,1.3 ± 0.1mag (100d)-1. The steeper decay rate seen in SN 2004et is likely due to dust formation in the explosion ejecta. Based on intermediate-band photometry,we derived the evolution of the feature lines [e.g.,Hα] of SNe 2004dj and 2004et which are similar in flux at comparable phases but perhaps with significantly different decay rates. The origin of the observed variations in the continuum and the feature lines is briefly discussed. 关 键 词：光谱特征 光度学 星云相 连续介质