Period-luminosity relations of type II Cepheids in the Magellanic Clouds
Period-luminosity relations of type II Cepheids in the Magellanic Clouds
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DOI：
10.1111/j.1365-2966.2010.18126.x
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发表时间：
2010-12
影响因子：
4.8
通讯作者：
N. Matsunaga;M. Feast;Igor Soszynski Kiso Observatory;U. Tokyo;South African astronomical Observatory;U. C. Town;W. University
中科院分区：
文献类型：
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作者：
N. Matsunaga;M. Feast;Igor Soszynski Kiso Observatory;U. Tokyo;South African astronomical Observatory;U. C. Town;W. University
根据OGLE-III、IRSF/SIRIUS等资料，导出了小麦哲伦星云(SMC)中II型造父变星(T2Cs)的周期-光度关系(PLR)，并与大麦哲伦星云(LMC)和银河系球状星系团的结果进行了比较。发现了PLR坡度从一个系统到另一个系统变化的证据。单独处理长周期的T2Cs(W-VIr星)，在没有任何金属丰度校正的情况下，SMC-LMC的模差为0.39±0.05mag。这与基于不同距离指示器的模数的差异很好地吻合，特别是经典造父变星的PLR。周期较短的T2Cs(BLHER星)给出的SMC-LMC差较小，表明它们的绝对星等可能受到金属丰度或年龄效应的影响。结果表明，T2C周期的频率分布也随系统的不同而不同。
Period–luminosity relations (PLRs) of type II Cepheids (T2Cs) in the Small Magellanic Cloud (SMC) are derived based on OGLE-III, IRSF/SIRIUS and other data, and these are compared with results for the Large Magellanic Cloud (LMC) and Galactic globular clusters. Evidence is found for a change of the PLR slopes from system to system. Treating the longer period T2Cs (W Vir stars) separately gives an SMC–LMC modulus difference of 0.39 ± 0.05 mag without any metallicity corrections being applied. This agrees well with the difference in moduli based on different distance indicators, in particular the PLRs of classical Cepheids. The shorter period T2Cs (BL Her stars) give a smaller SMC–LMC difference suggesting that their absolute magnitudes might be affected either by metallicity or by age effects. It is shown that the frequency distribution of T2C periods also changes from system to system.