Friday, February 09, 2024 at 12:15 pm

JILA Foothills Room

Nivedita Mahesh, Cal Tech

"Probing the Cosmic Dawn: Efforts with EDGES and OVRO-LWA"

Abstract:

Standard cosmological models predict that the first astrophysical sources formed from a Universe filled with neutral hydrogen (HI) around one hundred million years after the Big Bang. The transition into Cosmic Dawn (CD) that seeded all the structures we see today can only be probed directly by the 21-cm line of HI. Redshifted by the Hubble expansion, HI emission, and absorption during CD is expected to be visible in radio frequencies between 40 and 100 MHz, tracing redshifts of 35 >z>13. Precisely characterized and carefully calibrated low-frequency instruments are necessary to measure the predicted ~ 10-200 mK brightness temperature of this redshifted 21-cm signal against bright galactic foregrounds.

In this talk, I will discuss two experiments I work with, designed to probe the Cosmic Dawn - EDGES and OVRO-LWA. I will touch on the efforts carried out by the EDGES team since the reported detection in Bowman et al. (2018), focusing on new analysis techniques and updates on the new EDGES 3 system. For the OVRO- Long Wavelength Array, I will present the details of the upgraded telescope and discuss the development efforts of the 21cm cosmology pipeline.

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