arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1005.3028astro-ph.CO
收藏

VLT LBG红移巡天I:z~3处~1000星系团的成团和动力学

The VLT LBG Redshift Survey I: Clustering and Dynamics of ~1000 Galaxies at z~3

Rich Bielby, T. Shanks, P. M. Weilbacher, L. Infante, N. H. M. Crighton, Carlos Bornancini, N. Bouché, P. Héraudeau, D. G. Lambas, J. Lowenthal, D. Minniti, N. … 展开作者

Rich Bielby, T. Shanks, P. M. Weilbacher, L. Infante, N. H. M. Crighton, Carlos Bornancini, N. Bouché, P. Héraudeau, D. G. Lambas, J. Lowenthal, D. Minniti, N. Padilla, P. Petitjean, T. Theuns

摘要:

我们提出了最初的成像和光谱数据获得的VLT VIMOS莱曼break星系调查的一部分。UBR(或UBVI)成像覆盖了以明亮的z>3类星体为中心的5个36'x36'的区域,使用莱曼破裂技术可以选择约21,000个2<z<3.5的候选星系。我们使用VIMOS进行了光谱跟踪,从总共19个VIMOS点测量了1020个z>2的LBG和10个z>2的类星体的红移。从星系光谱中,我们观测到ISM吸收线和Ly-alpha发射线红移之间的速度偏移为625 ± 510 km/s。本文用光度星表和分光星表分析了z~3星系团。在光度计的情况下,角关联函数w(θ)符合双幂律,其聚集标度长度为:r < 1 Mpc/h时,r_0 = 3.19+0.32-0.54 Mpc/h,较大标度时,r_0 = 4.59+0.31-0.33 Mpc/h。利用红移样品,我们估计了半投影关联函数w_p(sigma),发现VLT样品的r_0 = 3.67+0.23-0.24 Mpc/h,VLT+Keck组合样品的r_0 = 3.98+0.14-0.15 Mpc/h。从z空间关联函数出发,在上述xi(r)模型的假设下,我们发现VLT和Keck联合巡天观测所要求的星系速度色散为<w_z^2>^1/2 ~ 700 km/s,高于前人所发现的~400 km/s。我们还测量了引力增长率参数β(z=3)= 0.48+-0.17的值,这意味着b = 2.06+1.1-0.5的偏差值较低。这个值与星系团的振幅一致,即b = 2.22+-0.16,假设标准宇宙学,这意味着引力增长率的演化也与爱因斯坦引力一致。我们已经比较了我们的LBG集群振幅与较低的红移测量,并发现集群强度是不一致的低红移L* 螺旋简单的“长寿”星系模型。

英文摘要:

We present the initial imaging and spectroscopic data acquired as part of the VLT VIMOS Lyman-break galaxy Survey. UBR (or UBVI) imaging covers five 36'x36' fields centred on bright z>3 QSOs, allowing ~21,000 2<z<3.5 galaxy candidates to be selected using the Lyman-break technique. We performed spectroscopic follow-up using VIMOS, measuring redshifts for 1020 z>2 LBGs and 10 z>2 QSOs from a total of 19 VIMOS pointings. From the galaxy spectra, we observe a 625+-510 km/s velocity offset between the ISM absorption and Ly-alpha emission line redshifts. Using the photometric and spectroscopic catalogues, we have analysed the galaxy clustering at z~3. In the photometric case, the angular correlation function, w(theta), is well fit by a double power-law with clustering scale-length, r_0 = 3.19+0.32-0.54 Mpc/h for r < 1 Mpc/h and r_0 = 4.59+0.31-0.33 Mpc/h at larger scales. Using the redshift sample we estimate the semi-projected correlation function, w_p(sigma) and find r_0 = 3.67+0.23-0.24 Mpc/h for the VLT sample and r_0 = 3.98+0.14-0.15 Mpc/h for a combined VLT+Keck sample. From the z-space correlation functions and assuming the above xi(r) models, we find that the combined VLT and Keck surveys require a galaxy velocity dispersion, <w_z^2>^1/2 ~ 700 km/s, higher than the ~400 km/s found by previous authors. We also measure a value for the gravitational growth rate parameter of beta(z=3) = 0.48+-0.17, implying a low value for the bias of b = 2.06+1.1-0.5. This value is consistent with the galaxy clustering amplitude which gives b = 2.22+-0.16, assuming the standard cosmology, implying that the evolution of the gravitational growth rate is also consistent with Einstein gravity. We have compared our LBG clustering amplitudes with lower redshift measurements and find that the clustering strength is not inconsistent with that of low-redshift L* spirals for simple 'long-lived' galaxy models.

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。

↑