Probing ultralate reionization: direct measurements of the mean free path over 5 < z < 6
The mean free path of ionizing photons, λ mfp, is a critical parameter for modeling the intergalactic medium (IGM) both during and after reionization. We present direct measurements of λ mfp from QSO spectra over the redshift range 5 < z < 6, including the first measurements at z ≃ 5.3 and 5.6...
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2023 October 1
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| In: |
The astrophysical journal
Year: 2023, Volume: 955, Issue: 2, Pages: 1-13 |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/1538-4357/aceef4 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.3847/1538-4357/aceef4 Verlag, lizenzpflichtig, Volltext: https://dx.doi.org/10.3847/1538-4357/aceef4 |
| Author Notes: | Yongda Zhu, George D. Becker, Holly M. Christenson, Anson D’Aloisio, Sarah E. I. Bosman, Tom Bakx, Valentina D’Odorico, Manuela Bischetti, Christopher Cain, Frederick B. Davies, Rebecca L. Davies, Anna-Christina Eilers, Xiaohui Fan, Prakash Gaikwad, Martin G. Haehnelt, Laura C. Keating, Girish Kulkarni, Samuel Lai, Hai-Xia Ma, Andrei Mesinger, Yuxiang Qin, Sindhu Satyavolu, Tsutomu T. Takeuchi, Hideki Umehata and Jinyi Yang |
| Summary: | The mean free path of ionizing photons, λ mfp, is a critical parameter for modeling the intergalactic medium (IGM) both during and after reionization. We present direct measurements of λ mfp from QSO spectra over the redshift range 5 < z < 6, including the first measurements at z ≃ 5.3 and 5.6. Our sample includes data from the XQR-30 VLT large program, as well as new Keck/ESI observations of QSOs near z ∼ 5.5, for which we also acquire new [C ii] 158 μm redshifts with ALMA. By measuring the Lyman continuum transmission profile in stacked QSO spectra, we find , , , and pMpc at z = 5.08, 5.31, 5.65, and 5.93, respectively. Our results demonstrate that λ mfp increases steadily and rapidly with time over 5 < z < 6. Notably, we find that λ mfp deviates significantly from predictions based on a fully ionized and relaxed IGM as late as z = 5.3. By comparing our results to model predictions and indirect λ mfp constraints based on IGM Lyα opacity, we find that the evolution of λ mfp is consistent with scenarios wherein the IGM is still undergoing reionization and/or retains large fluctuations in the ionizing UV background well below redshift 6. |
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| Item Description: | Im Titel steht für kleiner das mathematische Zeichen Gesehen am 08.04.2024 |
| Physical Description: | Online Resource |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/1538-4357/aceef4 |