Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxies
The halo model offers a framework for investigating galaxy clustering, and for understanding the growth of galaxies and the distribution of galaxies of different types. Here, we use the halo model to study the small-scale clustering and halo occupation distribution (HOD) of the unWISE-Blue galaxy sa...
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| Format: | Article |
| Language: | English |
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Maynooth Academic Publishing
2025-04-01
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| Series: | The Open Journal of Astrophysics |
| Online Access: | https://doi.org/10.33232/001c.137297 |
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| author | Alex Krolewski Jensen Lawrence Will J. Percival |
| author_facet | Alex Krolewski Jensen Lawrence Will J. Percival |
| author_sort | Alex Krolewski |
| collection | DOAJ |
| description | The halo model offers a framework for investigating galaxy clustering, and for understanding the growth of galaxies and the distribution of galaxies of different types. Here, we use the halo model to study the small-scale clustering and halo occupation distribution (HOD) of the unWISE-Blue galaxy sample, an infrared-selected sample of $\sim$100 million galaxies across the entire extragalactic sky at $z\sim 0.5$ $-$ similar redshifts to the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS sample. Although the photometric unWISE galaxies cannot be easily split in redshift, we use their cross-correlation with the BOSS CMASS sample to tomographically probe the HOD of the unWISE galaxies at $0.45 < z < 0.75$. To do so, we develop a new method for applying the halo model to cross-correlations between a photometric sample and a spectroscopic sample in narrow redshift bins, incorporating halo exclusion, post-Limber corrections, and redshift-space distortions. We reveal strong evolution in the CMASS HOD, and modest evolution in the unWISE-Blue HOD. For unWISE-Blue, we find that the average bias and mean halo mass drop from $b = 1.6$ and $\log_{10}(M_{\mathrm{h}}/M_{\odot}) \sim 13.4$ at $z \sim 0.5$ to $b = 1.4$ and $\log_{10}(M_{\mathrm{h}}/M_{\odot}) \sim 13.1$ at $z \sim 0.7$, and that the satellite fraction drops modestly from $\sim$20% to $\sim$10% in the same range. These results are useful for creating mock samples of the unWISE-Blue galaxies. Furthermore, the techniques developed to obtain these results are applicable to other tomographic cross-correlations between photometric samples and narrowly-binned spectroscopic samples, such as clustering redshifts. |
| format | Article |
| id | doaj-art-3d8ced892b4f43a3ad8c60601f5d478f |
| institution | Kabale University |
| issn | 2565-6120 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Maynooth Academic Publishing |
| record_format | Article |
| series | The Open Journal of Astrophysics |
| spelling | doaj-art-3d8ced892b4f43a3ad8c60601f5d478f2025-08-20T03:33:43ZengMaynooth Academic PublishingThe Open Journal of Astrophysics2565-61202025-04-01810.33232/001c.137297Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxiesAlex KrolewskiJensen LawrenceWill J. PercivalThe halo model offers a framework for investigating galaxy clustering, and for understanding the growth of galaxies and the distribution of galaxies of different types. Here, we use the halo model to study the small-scale clustering and halo occupation distribution (HOD) of the unWISE-Blue galaxy sample, an infrared-selected sample of $\sim$100 million galaxies across the entire extragalactic sky at $z\sim 0.5$ $-$ similar redshifts to the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS sample. Although the photometric unWISE galaxies cannot be easily split in redshift, we use their cross-correlation with the BOSS CMASS sample to tomographically probe the HOD of the unWISE galaxies at $0.45 < z < 0.75$. To do so, we develop a new method for applying the halo model to cross-correlations between a photometric sample and a spectroscopic sample in narrow redshift bins, incorporating halo exclusion, post-Limber corrections, and redshift-space distortions. We reveal strong evolution in the CMASS HOD, and modest evolution in the unWISE-Blue HOD. For unWISE-Blue, we find that the average bias and mean halo mass drop from $b = 1.6$ and $\log_{10}(M_{\mathrm{h}}/M_{\odot}) \sim 13.4$ at $z \sim 0.5$ to $b = 1.4$ and $\log_{10}(M_{\mathrm{h}}/M_{\odot}) \sim 13.1$ at $z \sim 0.7$, and that the satellite fraction drops modestly from $\sim$20% to $\sim$10% in the same range. These results are useful for creating mock samples of the unWISE-Blue galaxies. Furthermore, the techniques developed to obtain these results are applicable to other tomographic cross-correlations between photometric samples and narrowly-binned spectroscopic samples, such as clustering redshifts.https://doi.org/10.33232/001c.137297 |
| spellingShingle | Alex Krolewski Jensen Lawrence Will J. Percival Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxies The Open Journal of Astrophysics |
| title | Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxies |
| title_full | Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxies |
| title_fullStr | Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxies |
| title_full_unstemmed | Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxies |
| title_short | Tomographic halo model of the unWISE-Blue galaxies using cross-correlations with BOSS CMASS galaxies |
| title_sort | tomographic halo model of the unwise blue galaxies using cross correlations with boss cmass galaxies |
| url | https://doi.org/10.33232/001c.137297 |
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