TY  - JOUR
AU  - Forconi, M.
AU  - Ruchika
AU  - Melchiorri, A.
AU  - Mena, O.
AU  - Menci, N.
PY  - 2023
DA  - 2023//
TI  - Do the early galaxies observed by JWST disagree with Planck's CMB polarization measurements?
T2  - J. Cosmol. Astropart. Phys.
JO  - Journal of Cosmology and Astroparticle Physics
SP  - 012
EP  - 16pp
VL  - 10
IS  - 10
PB  - IOP Publishing Ltd
KW  - cosmological parameters from CMBR
KW  - high redshift galaxies
KW  - CMBR polarisation
KW  - reionization
AB  - The recent observations from the James Webb Space Telescope have led to a surprising discovery of a significant density of massive galaxies with masses of M >= 10(10.5)M(circle dot) at redshifts of approximately z similar to 10. This corresponds to a stellar mass density of roughly rho* similar to 10(6)M(circle dot) Mpc(-3). Despite making conservative assumptions regarding galaxy formation, this finding may not be compatible with the standard.CDM cosmology that is favored by observations of CMB Anisotropies from the Planck satellite. In this paper, we confirm the substantial discrepancy with Planck's results within the.CDM framework. Assuming a value of is an element of = 0.2 for the efficiency of converting baryons into stars, we indeed find that the.CDM model is excluded at more than 99.7% confidence level (C.L.). An even more significant exclusion is found for is an element of similar to 0.1, while a better agreement, but still in tension at more than 95%, is obtained for is an element of = 0.32. This tension, as already discussed in the literature, could arise either from systematics in the JWST measurements or from new physics. Here, as a last-ditch effort, we point out that disregarding the large angular scale polarization obtained by Planck, which allows for significantly larger values of the matter clustering parameter sigma(8), could lead to better agreement between Planck and JWST within the.CDM framework. Assuming.CDM and no systematics in the current JWST results, this implies either an unknown systematic error in current large angular scale CMB polarization measurements or an unidentified physical mechanism that could lower the expected amount of CMB polarization produced during the epoch of reionization. Interestingly, the model compatible with Planck temperature-only data and JWST observation also favors a higher Hubble constant H-0 = 69.0 +/- 1.1 km/s/Mpc at 68% C.L., in better agreement with observations based on SN-Ia luminosity distances.
SN  - 1475-7516
UR  - https://arxiv.org/abs/2306.07781
UR  - https://doi.org/10.1088/1475-7516/2023/10/012
DO  - 10.1088/1475-7516/2023/10/012
LA  - English
N1  - WOS:001142721200001
ID  - Forconi_etal2023
ER  -