http://arxiv.org/abs/2305.00999
JWST has opened up a new observational probe of our Universe. The early data release by JWST have revealed several high redshift massive galaxy candidates by photometry, and some of them have been confirmed spectroscopically. We use these observations to study their implications on the primordial power spectrum. In the first part of this work, we use the data from the CEERS photometric survey, along with respective spectroscopic updates, to compute the cumulative comoving stellar mass density. We find that a very high star formation efficiency (unlikely in various theoretical scenarios) is required to explain these observations within $\Lambda$CDM cosmology. We show that the tension can be eased if the primordial power spectrum has a blue tilt on small length scales. The required blue tilt depends on the currently unknown star formation efficiency in these galaxy candidates. In the second part of this work, we study the spectroscopically confirmed galaxies reported in the JADES survey at redshift $z \gtrsim 10$, which have been shown to be consistent with $\Lambda$CDM cosmology. We investigate the implications of these measurements on a red-tilted primordial power spectrum. For these galaxies, we estimate the star formation efficiency from an earlier observation of galaxies (with similar redshifts) by the Spitzer telescope. We find that the star formation efficiency is an order of magnitude smaller than that required to explain the CEERS photometric observations mentioned earlier. Using the estimated star formation efficiency, we find the strongest constraints on the red tilt of the power spectrum on certain length scales. Our study shows that JWST observations will be an excellent probe of the power spectrum and can lead to novel discoveries.
P. Parashari and R. Laha
Wed, 3 May 23
62/67
Comments: 6 pages, 5 figures, Comments and suggestions are welcome