The impact of cosmic dust on supernova cosmology
The impact of cosmic dust on supernova cosmology
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DOI：
10.1111/j.1365-2966.2006.10825.x
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发表时间：
2006-03
影响因子：
4.8
通讯作者：
Pier Stefano Corasaniti
中科院分区：
文献类型：
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作者：
Pier Stefano Corasaniti
星系间灰尘的消光在Ia型超新星的标准烛光关系中引入了星等红移相关的偏移。与无尘宇宙相比，这导致高估了光度距离。量化这种系统效应的振幅对于精确确定暗能量参数至关重要。本文从宇宙的恒星形成历史和尘埃颗粒的物理性质出发，建立了灰尘消光的模型。我们关注一类满足当前观测约束的宇宙尘埃模型。这些可以在z = 1.7时产生高达0.08等的消光，并可能破坏未来SN调查的暗能量参数推断。特别是依赖于尘埃模型，我们发现一个未计算的消光可以通过将其最佳拟合值从其真实值移动到20%而使恒定暗能量状态方程w的估计产生偏差。近红外宽带光度法很难检测到这种效应，而巴尔默线的诱导衰减需要高信噪比光谱。事实上，红外光谱将需要用于高红移SNe。宇宙尘埃的消光也可能导致距离-对偶关系的可探测破坏。对星系间介质的物理学有更全面的了解是精确模拟星系间尘埃的必要条件。由于较大的星等色散，电流光度距离测量对这种可能的消光效应不敏感。相比之下，如果我们希望在即将到来的Ia超新星调查中揭示暗能量的真实本质，就必须考虑到这些因素。
Extinction by intergalactic grey dust introduces a magnitude redshift-dependent offset in the standard‐candle relation of supernova Type Ia. This leads to overestimated luminosity distances compared to a dust-free universe. Quantifying the amplitude of this systematic effect is crucial for an accurate determination of the dark energy parameters. In this paper, we model the grey dust extinction in terms of the star formation history of the Universe and the physical properties of the dust grains. We focus on a class of cosmic dust models which satisfy current observational constraints. These can produce an extinction as large as 0.08 mag at z = 1.7 and potentially disrupt the dark energy parameter inference from future SN surveys. In particular depending on the dust model, we find that an unaccounted extinction can bias the estimation of a constant dark energy equation of state w by shifting its best-fitting value up to 20 per cent from its true value. Near-IR broad-band photometry will hardly detect this effect, while the induced decrement of the Balmer lines requires high signal-to-noise spectra. Indeed, IR-spectroscopy will be needed for high-redshift SNe. Cosmic dust extinction may also cause a detectable violation of the distance‐duality relation. A more comprehensive knowledge of the physics of the intergalactic medium is necessary for an accurate modelling of intergalactic dust. Due to the large magnitude dispersion current luminosity distance measurements are insensitive to such possible extinction effects. In contrast, these must be taken into account if we hope to disclose the true nature of dark energy with the upcoming generation of SN Ia surveys.