Forecasting constraints on the high-z IGM thermal state from the Lyman-α forest flux autocorrelation function
The autocorrelation function of the Lyman-α (Ly α) forest flux from high-z quasars probes the small-scale structure of the intergalactic medium (IGM). The thermal state of the IGM, determined by the physics of reionization, sets the small-scale power observed in the Ly α forest. To explore the sensi...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad de Sevilla (US) |
| Repositorio: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/174966 |
| Acceso en línea: | https://hdl.handle.net/11441/174966 https://doi.org/10.1093/mnras/staf753 |
| Access Level: | acceso abierto |
| Palabra clave: | Methods: statistical Intergalactic medium Quasars: absorption lines Dark ages Reionization First stars |
| Sumario: | The autocorrelation function of the Lyman-α (Ly α) forest flux from high-z quasars probes the small-scale structure of the intergalactic medium (IGM). The thermal state of the IGM, determined by the physics of reionization, sets the small-scale power observed in the Ly α forest. To explore the sensitivity of the autocorrelation function to the IGM’s thermal state, we compute the autocorrelation function from a cosmological hydrodynamical simulation with an instantaneous reionization model and 135 post-processed thermal states. Using mock data sets of 20 quasars, we forecast constraints on T0 and γ , which characterize the post-processed IGM thermalstate, at 5.4 ≤ z ≤ 6. While this model simplifiesthe IGM’sthermalstate, itserves as a key firststep in assessing future observational prospects. We also perform an inference test on mocks and re-weight out posterior distributions to guarantee that they exhibit statistically correct behaviour. At z = 5.4, we find that an idealized data set constrains T0 to 59 per cent and γ to 16 per cent at the 1σ equivalent confidence level. To explore more realistic, non-instantaneous reionization scenarios, we analyse four models combining temperature and ultraviolet background (UVB) fluctuations at z = 5.8. We find that mock data generated from a model with both temperature and UVB fluctuations can rule out a model with only temperature fluctuations at the > 1σ level 73.9 per cent of the time. |
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