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arXiv 1602.02596astro-ph.COastro-ph.GA
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SN Ia主星系性质如何影响宇宙学参数

How SN Ia host-galaxy properties affect cosmological parameters

H. Campbell, M. Fraser, G. Gilmore

摘要:

我们提出了一个系统的研究Ia型超新星(SN Ia)的属性之间的关系,和他们的宿主星系的特征,使用的样本581 SNe Ia从完整的斯隆数字巡天II(SDSS-II)SN调查。我们还研究了这对由SNe~Ia导出的宇宙学约束的影响。与之前的研究相比,我们的样本大了$>4$的一倍,并且覆盖了更大的红移范围(高达z~0.5),这直接适用于宇宙学兴趣的体积。我们测量到主星系恒星质量与SN~Ia哈勃残差(HR)之间存在显著的相关性(>5σ)。我们还发现,在低金属量星系中,主星系质量和HR的相关性比SN~Ia的相关性要陡-0. 11 $\mathrm{mag}/\mathrm{log}(\mathrm{M}_{\mathrm{host}}/\mathrm{M}_{\odot})$.我们测试的宇宙学分析的影响,使用主机参数和HR之间的最佳拟合相关性,并允许一个额外的自由参数在适合占主机属性,我们然后边缘化时,确定宇宙学参数。我们看到状态方程参数$w$向更负值的转变,以及在应用质量或金属丰度校正后向更低值的$Ω_\mathrm{m}$的转变。主星系恒星质量修正的宇宙学参数的变化与以前的研究一致。我们找到了$Ω_{\mathrm{m}} =0.266_{-0.016}^{+0.016}$、$Ω_Λ=0.740_{-0.018}^{+0.018}$和$w=-1.151_{-0.121}^{+0.123}$的最佳拟合宇宙学(仅统计误差)。

英文摘要:

We present a systematic study of the relationship between Type Ia Supernova (SN Ia) properties, and the characteristics of their host galaxies, using a sample of 581 SNe Ia from the full Sloan Digital Sky Survey II (SDSS-II) SN Survey. We also investigate the effects of this on the cosmological constraints derived from SNe~Ia. Compared to previous studies, our sample is larger by a factor of $>4$, and covers a substantially larger redshift range (up to z~0.5), which is directly applicable to the volume of cosmological interest. We measure a significant correlation (>5σ) between the host-galaxy stellar-mass and the SN~Ia Hubble Residuals (HR). We find a weak correlation (1.4σ) between the host-galaxy metallicity as measured from emission lines in the spectra, and the SN~Ia HR. We also find evidence that the slope of the correlation between host-galaxy mass and HR is -0.11 $\mathrm{mag}/\mathrm{log}(\mathrm{M}_{\mathrm{host}}/\mathrm{M}_{\odot})$ steeper in lower metallicity galaxies. We test the effects on a cosmological analysis using both the derived best-fitting correlations between host parameters and HR, and by allowing an additional free parameter in the fit to account for host properties which we then marginalize over when determining cosmological parameters. We see a shift towards more negative values of the equation of state parameter $w$, along with a shift to lower values of $Ω_\mathrm{m}$ after applying mass or metallicity corrections. The shift in cosmological parameters with host-galaxy stellar-mass correction is consistent with previous studies. We find a best-fitting cosmology of $Ω_{\mathrm{m}} =0.266_{-0.016}^{+0.016}$, $Ω_Λ=0.740_{-0.018}^{+0.018}$ and $w=-1.151_{-0.121}^{+0.123}$ (statistical errors only).

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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