[O II] as an Effective Indicator of the Dependence Between the Standardised Luminosities of Type Ia Supernovae and the Properties of their Host Galaxies
B. Martin, C. Lidman, D. Brout, B. E. Tucker, M. Dixon, P. Armstrong
我们从 Foundation Supernova survey 中获取了 75 个 Ia 型超新星宿主星系的 IFU 光谱，以寻找单个星系性质与超新星哈勃残差之间的相关性。在应用了光变曲线宽度和超新星颜色的标准改正之后，我们发现哈勃残差与 [O II] λλ 3727, 3729 双线的等值宽度（2.3σ）之间存在相关性，该等值宽度是恒星形成率密度（sSFR）的一个指标。当按超新星颜色对我们的样本进行划分时，我们没有发现影响 EW[O II] 与哈勃残差之间相关性的颜色依赖性。然而，当按颜色划分时，我们揭示了蓝色 Ia 型超新星的哈勃残差与巴耳末减缩（2.2σ）之间的相关性，巴耳末减缩是尘埃消光的一个指标。在应用质量阶跃改正后，这些相关性仍然存在，这表明质量阶跃改正并未完全解决用于标准化 Ia 型超新星的颜色改正的局限性。我们不是采用质量改正，而是根据恒星形成星系可测量的 EW[O II] 对其中的超新星进行改正。我们发现这种改正也消除了宿主星系质量阶跃，同时大大降低了蓝色 Ia 型超新星与巴耳末减缩相关性的显著性。我们发现，对 EW[O II] 进行改正，无论是作为质量阶跃的补充还是替代，都可能进一步减小哈勃图中的弥散。
英文摘要：
We have obtained IFU spectra of 75 SN Ia host galaxies from the Foundation Supernova survey to search for correlations between the properties of individual galaxies and SN Hubble residuals. After standard corrections for light-curve width and SN colour have been applied, we find correlations between Hubble residuals and the equivalent width of the [O II] $λλ$ 3727, 3729 doublet (2.3$σ$), an indicator of the specific star formation rate (sSFR). When splitting our sample by SN colour, we find no colour dependence impacting the correlation between EW[O II] and Hubble residual. However, when splitting by colour, we reveal a correlation between the Hubble residuals of blue SNe Ia and the Balmer decrement (2.2$σ$), an indicator of dust attenuation. These correlations remain after applying a mass-step correction, suggesting that the mass-step correction does not fully account for the limitations of the colour correction used to standardise SNe Ia. Rather than a mass correction, we apply a correction to SNe from star forming galaxies based on their measurable EW[O II]. We find that this correction also removes the host galaxy mass step, while also greatly reducing the significance of the correlation with the Balmer decrement for blue SNe Ia. We find that correcting for EW[O II], in addition to or in place of the mass-step, may further reduce the scatter in the Hubble diagram.
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Peking University（北京大学）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Central China Normal University（华中师范大学）；Institute of Astrophysics, Central China Normal University（华中师范大学天体物理研究所）；Education Research and Application Center, National Astronomical Data Center（国家天文台教育研究与应用中心）
