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| Main Authors: | , , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2506.22064 |
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| _version_ | 1866918072857657344 |
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| author | Chavan, Pankaj Sarkar, Tapomoy Guha Sen, Anjan A |
| author_facet | Chavan, Pankaj Sarkar, Tapomoy Guha Sen, Anjan A |
| contents | This work serves two-fold purpose. Firstly, we provide an alternative to the traditional method of determining the growth rate of density perturbations $f(z)$. In usual practice, $f(z)$ can not be directly measured from tracer clustering at some redshift without knowledge of the bias. While the bayron acoustic oscillation (BAO) imprint allows the determination of $(D_A(z), H(z))$, redshift space anisotropy (RSD) allows the measurement of a quantity $f_8(z) = f(z) σ_{8,0} D_{+}(z)$. To extract $f(z)$ from $f_8(z)$, one usually requires some other data set. We show that precise BAO and RSD measurements in and around some key redshifts themselves can solely reconstruct $f(z)$ without requiring any other data sets. Secondly, we extend this approach to another tracer, namely the post-reionization 21-cm brightness temperature intensity maps. We demonstrate that the measured $f(z)$ from purely redshift space clustering allows us to measure the 21-cm bias, which is a largely unknown quantity. This may help interpret the observed intensity mapping signal in the future. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_22064 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Disentangling the growth rate of perturbations from the HI bias using only clustering data from galaxy surveys Chavan, Pankaj Sarkar, Tapomoy Guha Sen, Anjan A Cosmology and Nongalactic Astrophysics This work serves two-fold purpose. Firstly, we provide an alternative to the traditional method of determining the growth rate of density perturbations $f(z)$. In usual practice, $f(z)$ can not be directly measured from tracer clustering at some redshift without knowledge of the bias. While the bayron acoustic oscillation (BAO) imprint allows the determination of $(D_A(z), H(z))$, redshift space anisotropy (RSD) allows the measurement of a quantity $f_8(z) = f(z) σ_{8,0} D_{+}(z)$. To extract $f(z)$ from $f_8(z)$, one usually requires some other data set. We show that precise BAO and RSD measurements in and around some key redshifts themselves can solely reconstruct $f(z)$ without requiring any other data sets. Secondly, we extend this approach to another tracer, namely the post-reionization 21-cm brightness temperature intensity maps. We demonstrate that the measured $f(z)$ from purely redshift space clustering allows us to measure the 21-cm bias, which is a largely unknown quantity. This may help interpret the observed intensity mapping signal in the future. |
| title | Disentangling the growth rate of perturbations from the HI bias using only clustering data from galaxy surveys |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2506.22064 |