ملخص
The Murchison Widefield Array (MWA) team has derived new upper limits on the spherically averaged power spectrum of the 21-cm signal at six redshifts in the range z ≈ 6.5-8.7. We use these upper limits and a Bayesian inference framework to derive constraints on the ionization and thermal state of the intergalactic medium (IGM) as well as on the strength of a possible additional radio background. We do not find any constraints on the state of the IGM for z ≳ 7.8 if no additional radio background is present. In the presence of such a radio background, the 95 per cent credible intervals of the disfavoured models at redshift ≳ 6.5 correspond to an IGM with a volume-averaged fraction of ionized regions below 0.6 and an average gas temperature ≲ 103 K. In these models, the heated regions are characterized by a temperature larger than that of the radio background, and by a distribution with characteristic size ≲ 10 h−1 Mpc and a full width at half maximum (FWHM) of ≲ 30 h−1 Mpc. Within the same credible interval limits, we exclude an additional radio background of at least 0.008 per cent of the CMB at 1.42 GHz.
اللغة الأصلية | الإنجليزيّة |
---|---|
الصفحات (من إلى) | 4551-4562 |
عدد الصفحات | 12 |
دورية | Monthly Notices of the Royal Astronomical Society |
مستوى الصوت | 503 |
رقم الإصدار | 3 |
المعرِّفات الرقمية للأشياء | |
حالة النشر | نُشِر - 1 مايو 2021 |
ملاحظة ببليوغرافية
Funding Information:We would like to thank the anonymous referee for insightful comments. We thank Cathryn M. Trott for providing the lists of the MWA upper limits and the corresponding errors, and Bradley Greig for useful discussion related to this work. We acknowledge that the results in this paper have been achieved using the PRACE Research Infrastructure resources Curie based at the Tr?s Grand Centre de Calcul (TGCC) operated by CEA near Paris, France, and Marenostrum based in the Barcelona Supercomputing Center, Spain. Time on these resources was awarded by PRACE under PRACE4LOFAR grants 2012061089 and 2014102339 as well as under the Multi-scale Reionization grants 2014102281 and 2015122822. The computations were partly enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC) at PDC partially funded by the Swedish Research Council through grant agreement no. 2018-05973. RG and SZ furthermore acknowledge support by the Israel Science Foundation (grant no. 255/18). GM is supported by Swedish Research Council grants 2016-03581 and 2020-04691.
Funding Information:
We would like to thank the anonymous referee for insightful comments. We thank Cathryn M. Trott for providing the lists of the MWA upper limits and the corresponding errors, and Bradley Greig for useful discussion related to this work. We acknowledge that the results in this paper have been achieved using the PRACE Research Infrastructure resources Curie based at the Très Grand Centre de Calcul (TGCC) operated by CEA near Paris, France, and Marenos-trum based in the Barcelona Supercomputing Center, Spain. Time on these resources was awarded by PRACE under PRACE4LOFAR grants 2012061089 and 2014102339 as well as under the Multi-scale Reionization grants 2014102281 and 2015122822. The computations were partly enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC) at PDC partially funded by the Swedish Research Council through grant agreement no. 2018-05973. RG and SZ furthermore acknowledge support by the Israel Science Foundation (grant no. 255/18). GM is supported by Swedish Research Council grants 2016-03581 and 2020-04691.
Publisher Copyright:
© 2021 The Author(s)