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arXiv 1111.1791astro-ph.SR
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Spitzer IRAC波段造父变星的理论周期-亮度和周期-颜色关系

Theoretical Cepheid Period-Luminosity And Period-Color Relations In Spitzer IRAC Bands

Chow-Choong Ngeow, Marcella Marconi, Ilaria Musella, Michele Cignoni, Shashi M. Kanbur

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13 pages, 14 figures and 5 tables, ApJ accepted
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摘要：

本文根据一系列不同金属和氦丰度的理论脉动模型，研究了Spitzer IRAC波段的合成周期光度关系。这些合成的P-L关系的选择集进行了比较的经验IRAC波段P-L关系最近确定的银河系和麦哲伦云造父变星。对于银河系的情况，从模型组（Y = 0.26，Z = 0.01），（Y = 0.26，Z = 0.02）和（Y = 0.28，Z = 0.02）的综合P-L关系符合经验银河系的P-L关系从哈勃空间望远镜的望远镜望远镜。对于麦哲伦云造父变星，由（Y = 0.25，Z = 0.008）模型集合成的P-L关系与经验的大麦云（LMC）和小麦哲伦云（SMC）P-L关系都符合。对所有模型集的合成P-L关系的分析表明，IRAC带P-L关系可能不独立于金属丰度，因为P-L斜率和截距可能受到金属丰度和/或氦丰度的影响。我们还推导了IRAC波段的合成周期色（P-C）关系。非零合成的P-C关系，发现某些组合的IRAC带通滤波器和金属。然而，合成的P-C关系与最近发现的银河系造父变星的[3.6]-[8.0] P-C关系不一致。另一方面，如果采用1.0 < log（P）< 1.8的周期范围，则来自（Y = 0.25，Z = 0.008）模型集的合成[3.6]-[4.5] P-C斜率与经验LMC P-C对应物非常一致。

英文摘要：

In this paper the synthetic period-luminosity (P-L) relations in Spitzer's IRAC bands, based on a series of theoretical pulsation models with varying metal and helium abundance, were investigated. Selected sets of these synthetic P-L relations were compared to the empirical IRAC band P-L relations recently determined from Galactic and Magellanic Clouds Cepheids. For the Galactic case, synthetic P-L relations from model sets with (Y = 0.26, Z = 0.01), (Y = 0.26, Z = 0.02) and (Y = 0.28, Z = 0.02) agree with the empirical Galactic P-L relations derived from the Hubble Space Telescope parallaxes. For Magellanic Cloud Cepheids, the synthetic P-L relations from model sets with (Y = 0.25, Z = 0.008) agree with both of the empirical Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) P-L relations. Analysis of the synthetic P-L relations from all model sets suggested that the IRAC band P-L relations may not be independent of metallicity, as the P-L slopes and intercepts could be affected by the metallicity and/or helium abundance. We also derive the synthetic period color(P-C) relations in the IRAC bands. Non-vanishing synthetic P-C relations were found for certain combinations of IRAC band filters and metallicity. However, the synthetic P-C relations disagreed with the [3.6]-[8.0] P-C relation recently found for the Galactic Cepheids. The synthetic [3.6]-[4.5] P-C slope from (Y = 0.25, Z = 0.008) model set, on the other hand, is in excellent agreement to the empirical LMC P-C counterpart, if a period range of 1.0 < log(P) < 1.8 is adopted.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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