arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.00070astro-ph.COastro-ph.GAastro-ph.IM
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从星系视差直接几何测量哈勃常数:Vera C.的预测。鲁宾天文台和南希格雷斯罗马太空望远镜

Direct geometrical measurement of the Hubble constant from galaxy parallax: predictions for the Vera C. Rubin Observatory and Nancy Grace Roman Space Telescope

Rupert A. C. Croft

摘要:

我们调查的可能性,由于地球的运动相对于CMB框架(宇宙长期视差)的星系视差偏移的统计检测可以由维拉C。鲁宾天文台的遗产调查的空间和时间(LSST)或南希格雷斯罗马太空望远镜(NGST),并用于测量哈勃常数。我们做了模拟星系调查,从一个大的N-体模拟扩展到红移z=0.06,并包括天体测量误差的LSST和NGSINS的科学要求,红移误差和特有的速度。我们包括光谱红移的最亮的星系(r < 18)在基准的情况下。我们使用这些星表来测量视差与红移,各种假设的调查参数和分析技术。我们发现,为了使一个有竞争力的测量,将是必要的模型和星系自行的特殊速度分量的校正。也有必要将扩展源的天体测量推向一个新的领域,并将来自已分辨星系的不同元素的信息结合起来。在附录中,我们描述了一些简单的测试星系图像配准产生相对有前途的结果。对于我们的基准调查参数,我们预测的均方根误差H 0的直接几何测量为2.8%的LSST和0.8%的NGSINS。

英文摘要:

We investigate the possibility that a statistical detection of the galaxy parallax shift due to the Earth's motion with respect to the CMB frame (cosmic secular parallax) could be made by the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) or by the Nancy Grace Roman Space Telescope (NGRST), and used to measure the Hubble constant. We make mock galaxy surveys which extend to redshift z=0.06 from a large N-body simulation, and include astrometric errors from the LSST and NGRST science requirements, redshift errors and peculiar velocities. We include spectroscopic redshifts for the brightest galaxies (r < 18) in the fiducial case. We use these catalogues to make measurements of parallax versus redshift,for various assumed survey parameters and analysis techniques. We find that in order to make a competitive measurement it will be necessary to model and correct for the peculiar velocity component of galaxy proper motions. It will also be necessary to push astrometry of extended sources into a new regime, and combine information from the different elements of resolved galaxies. In an appendix we describe some simple tests of galaxy image registration which yield relatively promising results. For our fiducial survey parameters, we predict an rms error on the direct geometrical measurement of H0 of 2.8% for LSST and 0.8% for NGRST.

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