| Name: | Shikhar Mittal |
| Affiliation: | Tata Institute of Fundamental Research, Mumbai |
| Conference ID : | ASI2023_587 |
| Title : | Implications of the global 21-cm spectrum for high-redshift galaxies and JWST galaxy surveys |
| Authors : | Shikhar Mittal (TIFR)
Girish Kulkarni (TIFR) |
| Mode of Presentation: | Oral |
| Abstract Category : | General Relativity and Cosmology |
| Abstract : | The first JWST results have taken us closer to the goal of directly measuring star formation at the cosmic dawn. Various spectroscopic and photometric galaxy surveys plan to push this work further in the near future. In my talk, I will present a new method to derive falsifiable predictions for JWST galaxy surveys from measurements of the global 21-cm signal from the cosmic dawn. The linear dependence of the 21-cm signal on galaxy formation physics makes it easy to read out quantities such as galaxy luminosity functions (GLFs) under a bare minimum of assumptions. I will then discuss the peculiar shape of the EDGES measurement of the 21-cm signal. While a large amount of work has been devoted to the amplitude of the EDGES measurement, not much has been said about its shape. I will show that the shape of the 21-cm signal measured by EDGES requires either unphysically large modifications to the UV and X-ray SEDs of galaxies at cosmic dawn or an excess over extrapolations of low-redshifts GLF that can be measured by the JWST. This not only provides a means to develop models to analyse arbitrary 21-cm profiles but also paves a path forward to synergise 21-cm and JWST measurements. |
