Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
A Detection of Cosmological 21 cm Emission from CHIME in Cross-correlation with eBOSS Measurements of the Lyα Forest
Ist Teil von
The Astrophysical journal, 2024-03, Vol.963 (1), p.23
Ort / Verlag
Philadelphia: IOP Publishing
Erscheinungsjahr
2024
Link zum Volltext
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
We report the detection of 21 cm emission at an average redshift z¯=2.3 in the cross-correlation of data from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) with measurements of the Lyα forest from eBOSS. Data collected by CHIME over 88 days in the 400–500 MHz frequency band (1.8 < z < 2.5) are formed into maps of the sky and high-pass delay filtered to suppress the foreground power, corresponding to removing cosmological scales with k∥ ≲ 0.13 Mpc−1 at the average redshift. Line-of-sight spectra to the eBOSS background quasar locations are extracted from the CHIME maps and combined with the Lyα forest flux transmission spectra to estimate the 21 cm–Lyα cross-correlation function. Fitting a simulation-derived template function to this measurement results in a 9σ detection significance. The coherent accumulation of the signal through cross-correlation is sufficient to enable a detection despite excess variance from foreground residuals ∼6–10 times brighter than the expected thermal noise level in the correlation function. These results are the highest-redshift measurement of 21 cm emission to date, and they set the stage for future 21 cm intensity mapping analyses at z > 1.8.