The BINGO project. VI. Hi halo occupation distribution and mock building
The BINGO project. VI. Hi halo occupation distribution and mock building
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DOI：
10.1051/0004-6361/202140887
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Karin S. F. For
中科院分区：
文献类型：
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作者：
Jiajun Zhang;Pablo Motta;Camila P. Novaes;Filipe B. Abdalla;Andre A. Costa;Bin Wang;Zhenghao Zhu;Chenxi Shan;Haiguang Xu;Elcio Abdalla;Luciano Barosi;Francisco A. Brito;Amilcar Queiroz;Thyrso Villela;Carlos A. Wuensche;Elisa G. M. Ferreira;Karin S. F. For
BINGO (Baryon Acoustic Oscillations from Integrated Neutral Gas Observations.) is a radio telescope designed to survey from 980 MHz to 1260 MHz, observe the neutral Hydrogen (Hi) 21-cm line and detect BAO (Baryon Acoustic Oscillation) signal with Intensity Mapping technique. Here we present our method to generate mock maps of the 21-cm Intensity Mapping signal covering the BINGO frequency range and related test results. Aims. We would like to employ N-body simulations to generate mock 21-cm intensity map for BINGO and study what 21-cm intensity mapping observations can tell us about structure formation,Hi distribution and Hi mass-halo mass relation. Methods. We have fitted an Hi mass-halo mass relation from ELUCID semi-analytical galaxy catalog and applied to Horizen Run 4 halo catalog to generate the 21-cm mock map, named as HOD. We have also applied the abundance matching method, matched the Horizen Run 4 galaxy catalog with Hi mass function measured from ALFALFA, to generate the 21-cm mock map, named as HAM Results. We studied the angular power spectrum of the mock maps and the corresponding pixel histogram. The comparison between two different mock map generation method (HOD and HAM) is presented. We provided the fitting formula of ΩHi , Hi bias and the lognormal fitting parameter of the maps, which can be used to generate similar maps. We discussed the possibility of measuring ΩHi and Hi bias by comparing the angular power spectrum of the mock maps and the theoretical calculation. We also discussed the RSD (Redshift Space Distortion) effect, the nonlinear effect and the bin size effect in the mock map. Conclusions. By comparing the angular power spectrum measured from two different kinds of mock maps and the theoretical calculation, we find that the theoretical calculation can only fit to the mock result at large scale. At small scales, neither the linear calculation nor the halofit nonlinear calculation can provide accurate fitting, which reflects our poor understanding of nonlinear distribution of Hi and its scale-dependent bias. We have found that the bias is highly sensitive to the method of populating Hi in halos, which also means we can put constraints on the Hi distribution in halos by observing 21-cm intensity mapping. We have also illustrated that only with thin frequency bins (such as 2 MHz), we can discriminate the effect of Finger-of-God. All of our investigations using mocks provide useful guide for our expectation of BINGO experiments and other 21-cm intensity mapping experiments.
