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arXiv 1504.04088astro-ph.COastro-ph.GA
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来自SDSS/BOSS的莱曼α发射强度的大尺度聚类

Large-scale clustering of Lyman-alpha emission intensity from SDSS/BOSS

Rupert A. C. Croft, Jordi Miralda-Escudé, Zheng Zheng, Adam Bolton, Kyle S. Dawson, Jeffrey B. Peterson, Donald G. York, Daniel Eisenstein, Jon Brinkmann, Joel … 展开作者

Rupert A. C. Croft, Jordi Miralda-Escudé, Zheng Zheng, Adam Bolton, Kyle S. Dawson, Jeffrey B. Peterson, Donald G. York, Daniel Eisenstein, Jon Brinkmann, Joel Brownstein, Timothée Delubac, Andreu Font-Ribera, Jean-Christophe Hamilton, Khee-Gan Lee, Adam Myers, Nathalie Palanque-Delabrouille, Isabelle Pâris, Patrick Petitjean, Matthew M. Pieri, Nicholas P. Ross, Graziano Rossi, David J. Schlegel, Donald P. Schneider, Anže Slosar, José Vazquez, Matteo Viel, David H. Weinberg, Christophe Yèche

摘要:

通过测量Lya表面亮度与SDSS/BOSS类星体的互相关,我们探测到宇宙中红移z=2-3.5的Lya辐射的大尺度结构。我们使用一百万个光谱,目标是z<0.8的发光红星系,在从每个光谱中减去最佳拟合模型星系光谱后,作为高红移Lya表面亮度的估计。我们探测到的类星体-Lya发射互相关的形状与Lambda CDM模型一致,Ω_M =0.30^+0.10-0.07。这种互相关的预测幅度与平均Lya表面亮度<mu_alpha>、质量波动幅度以及类星体和Lya发射偏置因子的乘积成比例。利用已知的值,我们可以推断出<mu_alpha>(b_alpha/3)=(3.9 +/- 0.9)x 10^-21 erg/s cm^-2 A^-1 arcsec^-2,其中b_alpha是Lya发射偏置因子。如果Lya辐射的主要来源是恒星形成星系,我们推断在z=2-3.5时rho_SFR =(0.28 +/- 0.07)(3/b_alpha)/yr/Mpc ^3。对于b_alpha=3,这一数值比先前从单独探测到的Lya发射体得出的估计值高出21-35倍,但与从经灰尘校正的连续紫外线调查得出的总rho_SFR一致。因此,宇宙中97%的Lya发射在这些红移下在以前的Lya发射体调查中未被检测到。我们的测量结果比以前检测到的Lya发射体周围的微弱晕的叠加分析要大得多,但我们推测它来自于所有发光的恒星形成星系周围的类似Lya晕。我们还检测到类星体Lya发射互相关的红移空间各向异性,在3.0 sigma水平上发现证据表明它是径向拉长的,与辐射传输效应引起的扭曲一致(Zheng et al.(2011))。我们的测量代表的第一个应用程序的强度映射技术的光学观测。

英文摘要:

(Abridged) We detect the large-scale structure of Lya emission in the Universe at redshifts z=2-3.5 by measuring the cross-correlation of Lya surface brightness with quasars in SDSS/BOSS. We use a million spectra targeting Luminous Red Galaxies at z<0.8, after subtracting a best fit model galaxy spectrum from each one, as an estimate of the high-redshift Lya surface brightness. The quasar-Lya emission cross-correlation we detect has a shape consistent with a LambdaCDM model with Omega_M =0.30^+0.10-0.07. The predicted amplitude of this cross-correlation is proportional to the product of the mean Lya surface brightness, <mu_alpha>, the amplitude of mass fluctuations, and the quasar and Lya emission bias factors. Using known values, we infer <mu_alpha>(b_alpha/3) = (3.9 +/- 0.9) x 10^-21 erg/s cm^-2 A^-1 arcsec^-2, where b_alpha is the Lya emission bias factor. If the dominant sources of Lya emission are star forming galaxies, we infer rho_SFR = (0.28 +/- 0.07) (3/b_alpha) /yr/Mpc^3 at z=2-3.5. For b_alpha=3, this value is a factor of 21-35 above previous estimates from individually detected Lya emitters, although consistent with the total rho_SFR derived from dust-corrected, continuum UV surveys. 97% of the Lya emission in the Universe at these redshifts is therefore undetected in previous surveys of Lya emitters. Our measurement is much greater than seen from stacking analyses of faint halos surrounding previously detected Lya emitters, but we speculate that it arises from similar Lya halos surrounding all luminous star-forming galaxies. We also detect redshift space anisotropy of the quasar-Lya emission cross-correlation, finding evidence at the 3.0 sigma level that it is radially elongated, consistent with distortions caused by radiative-transfer effects (Zheng et al. (2011)). Our measurements represent the first application of the intensity mapping technique to optical observations.

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