Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys
Abstract The fluctuations produced during cosmic inflation may exhibit non-Gaussian characteristics that are imprinted in the large-scale structure of the Universe. This non-Gaussian imprint is an ultra-large scale signal that can be detected using the power spectrum. We focus on the local-type non-...
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SpringerOpen
2025-05-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | https://doi.org/10.1140/epjc/s10052-025-14241-7 |
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| author | Mponeng Kopana Sheean Jolicoeur Roy Maartens |
| author_facet | Mponeng Kopana Sheean Jolicoeur Roy Maartens |
| author_sort | Mponeng Kopana |
| collection | DOAJ |
| description | Abstract The fluctuations produced during cosmic inflation may exhibit non-Gaussian characteristics that are imprinted in the large-scale structure of the Universe. This non-Gaussian imprint is an ultra-large scale signal that can be detected using the power spectrum. We focus on the local-type non-Gaussianity $$f_\textrm{NL}$$ f NL and employ a multi-tracer analysis that combines different probes in order to mitigate cosmic variance and maximize the non-Gaussian signal. In our previous paper, we showed that combining spectroscopic galaxy surveys with 21 cm intensity mapping surveys in interferometer mode could lead to a $$\sim $$ ∼ 20–30% improvement in the precision on this non-Gaussian signal. Here we combine the same 21 cm experiments, including also single-dish surveys, with photometric galaxy surveys. The 21 cm single-dish surveys are based on MeerKAT and SKAO and the interferometric surveys are alike to HIRAX and PUMA. We implement foreground-avoidance filters and utilize models for the 21 cm thermal noise associated with single-dish and interferometer modes. The photometric galaxy surveys are similar to the DES and LSST. Our multi-tracer Fisher forecasts show a better precision for the combination of the photometric galaxy surveys and 21 cm interferometric surveys than with the 21 cm single-dish surveys – leading to at most an improvement of $$23\%$$ 23 % in the former case and $$16\%$$ 16 % in the latter case. Furthermore, we examine the impact of varying the foreground filter parameter, redshift range and sky area on the derived constraint. We find that the $$f_\textrm{NL}$$ f NL constraint is highly sensitive to both the redshift range and sky area. The foreground filter parameter shows negligible effect. |
| format | Article |
| id | doaj-art-bf800ab747f54f29b4bd3f6e26c56af2 |
| institution | DOAJ |
| issn | 1434-6052 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | SpringerOpen |
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| series | European Physical Journal C: Particles and Fields |
| spelling | doaj-art-bf800ab747f54f29b4bd3f6e26c56af22025-08-20T03:07:51ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522025-05-0185511410.1140/epjc/s10052-025-14241-7Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveysMponeng Kopana0Sheean Jolicoeur1Roy Maartens2Department of Physics and Astronomy, University of the Western CapeDepartment of Physics, Stellenbosch UniversityDepartment of Physics and Astronomy, University of the Western CapeAbstract The fluctuations produced during cosmic inflation may exhibit non-Gaussian characteristics that are imprinted in the large-scale structure of the Universe. This non-Gaussian imprint is an ultra-large scale signal that can be detected using the power spectrum. We focus on the local-type non-Gaussianity $$f_\textrm{NL}$$ f NL and employ a multi-tracer analysis that combines different probes in order to mitigate cosmic variance and maximize the non-Gaussian signal. In our previous paper, we showed that combining spectroscopic galaxy surveys with 21 cm intensity mapping surveys in interferometer mode could lead to a $$\sim $$ ∼ 20–30% improvement in the precision on this non-Gaussian signal. Here we combine the same 21 cm experiments, including also single-dish surveys, with photometric galaxy surveys. The 21 cm single-dish surveys are based on MeerKAT and SKAO and the interferometric surveys are alike to HIRAX and PUMA. We implement foreground-avoidance filters and utilize models for the 21 cm thermal noise associated with single-dish and interferometer modes. The photometric galaxy surveys are similar to the DES and LSST. Our multi-tracer Fisher forecasts show a better precision for the combination of the photometric galaxy surveys and 21 cm interferometric surveys than with the 21 cm single-dish surveys – leading to at most an improvement of $$23\%$$ 23 % in the former case and $$16\%$$ 16 % in the latter case. Furthermore, we examine the impact of varying the foreground filter parameter, redshift range and sky area on the derived constraint. We find that the $$f_\textrm{NL}$$ f NL constraint is highly sensitive to both the redshift range and sky area. The foreground filter parameter shows negligible effect.https://doi.org/10.1140/epjc/s10052-025-14241-7 |
| spellingShingle | Mponeng Kopana Sheean Jolicoeur Roy Maartens Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys European Physical Journal C: Particles and Fields |
| title | Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys |
| title_full | Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys |
| title_fullStr | Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys |
| title_full_unstemmed | Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys |
| title_short | Constraining primordial non-Gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys |
| title_sort | constraining primordial non gaussianity by combining photometric galaxy and 21 cm intensity mapping surveys |
| url | https://doi.org/10.1140/epjc/s10052-025-14241-7 |
| work_keys_str_mv | AT mponengkopana constrainingprimordialnongaussianitybycombiningphotometricgalaxyand21cmintensitymappingsurveys AT sheeanjolicoeur constrainingprimordialnongaussianitybycombiningphotometricgalaxyand21cmintensitymappingsurveys AT roymaartens constrainingprimordialnongaussianitybycombiningphotometricgalaxyand21cmintensitymappingsurveys |