State of the Universe

Reassessing the Constraints from SH0ES Extragalactic Cepheid Amplitudes on Systematic Blending Bias

by Dr. Doron Kushnir (Weizmann Institute)

Friday, June 23, 2023 from to (Asia/Kolkata)
at On zoom : https://us02web.zoom.us/j/82512956967?pwd=angyQ0ZDdHZUdzFUbjkybmxsWFNFUT09 Meeting ID: 825 1295 6967 Passcode: 384194
Description
The SH0ES collaboration Hubble constant determination is ∼5σ different from the Planck value, known as the Hubble tension. The accuracy of the Hubble constant measured with extragalactic Cepheids depends on robust stellar-crowding background estimation, where γ=0.24±0.05 mag is the required unaccounted systematic blending bias to resolve the Hubble tension. I will discuss a method to constrain γ by comparing the light curves amplitudes of extragalactic and MW Cepheids. A careful application of this method leads to an estimate of γ=0.013±0.057 mag. Although the obtained γ is consistent with zero, folding (in quadratures) it is ≈ 3.0σ away from aligning with Planck.