论文标题
加快谐波空间星系双光谱的可检测性
Speeding up the detectability of the harmonic-space galaxy bispectrum
论文作者
论文摘要
我们提出了一种方法，该方法首次允许我们估算由重力引起的谐波星系双光谱的信噪比（SNR），这是一种互补的探针，用于已经建立了良好的傅立叶空间群集分析。我们展示了如何考虑在多极空间中仅考虑$ \ sim1000 $三角形配置，这对应于因子$ \ Mathcal {o}（10^2）（10^2） - \ Mathcal {O}（10^3）$的计算加速度，取决于红shift bin，包括轻度的非线性量表。假设观察性规范与即将进行的光谱和光度星系调查一致，例如欧几里得卫星和平方公里阵列（第1阶段），我们表明：鉴于单个红移箱，光谱调查，光谱均匀的调查均超过了效得的光度测量；而且，由于射击量和红移箱的宽度平衡 - 红移$ z \ sim1 $带来的累积SNR比低红移$ z \ sim 0.5 $更高。我们最大的累积snr $ \ sim 15 $的结果表明，在狭窄（$Δz\ sim 0.01 $）的光谱红移箱中可以检测到谐波空间双光谱，即使仅包括轻度非线性尺度。层析成像的重建和包括高度非线性尺度的包含将通过即将进行的星系调查进一步提高可检测性。此外，我们讨论了如何使用Karhunen-Loève变换，检测分析仅需要$ 1 \ times 1 $协方差矩阵，用于单个红移箱。
We present a method that allows us for the first time to estimate the signal-to-noise ratio (SNR) of the harmonic-space galaxy bispectrum induced by gravity, a complementary probe to already well established Fourier-space clustering analyses. We show how to do it considering only $\sim1000$ triangle configurations in multipole space, corresponding to a computational speedup of a factor $\mathcal{O}(10^2)-\mathcal{O}(10^3)$, depending on the redshift bin, when including mildly non-linear scales. Assuming observational specifications consistent with forthcoming spectroscopic and photometric galaxy surveys like the Euclid satellite and the Square Kilometre Array (phase 1), we show: that given a single redshift bin, spectroscopic surveys outperform photometric surveys; and that -- due to shot-noise and redshift bin width balance -- bins at redshifts $z\sim1$ bring higher cumulative SNR than bins at lower redshifts $z \sim 0.5$. Our results for the largest cumulative SNR $\sim 15$ suggest that the harmonic-space bispectrum is detectable within narrow ($Δz \sim 0.01$) spectroscopic redshift bins even when including only mildly non-linear scales. Tomographic reconstructions and inclusion of highly non-linear scales will further boost detectability with upcoming galaxy surveys. In addition, we discuss how, using the Karhunen-Loève transform, a detection analysis only requires a $1 \times 1$ covariance matrix for a single redshift bin.
