Research Progress Meeting
Date: November 7, 2024
Time: 4:00- 5:00 pm
Location: Sessler Conference Room- 50A-5132 [In-Person and HYBRID]
Speaker: Taylor Hoyt (LBNL)
Title: Toward a Precision Cosmology Measurement of the Hubble Constant
Abstract: The local value of the Hubble constant (H0) derived from a Cepheid calibration of nearby supernovae (SNe) continues to disagree with values derived from a Lambda(or w)CDM interpretation of large scale cosmological datasets from, e.g., Planck or DESI. The Cepheid-SN and high-z values of H0 consistently come in close to 73 and 68 km/s/Mpc, respectively, with a latest claim that the Hubble tension has surpassed 5 sigma significance. At the same time, a calibration of the SNe based on the Tip of the Red Giant Branch (TRGB) distance indicator suggests significantly less of a tension, consistently returning values near 69.5 km/s/Mpc. This persistent local Hubble Tension indicates that classical H0 experiments have not yet reached the level of accuracy required of a “precision cosmology” measurement.
To this end, I will discuss ongoing efforts aimed at evaluating, and ultimately reducing, the amount that underestimated systematic errors could contribute to SN-derived H0 measurements and subsequently bias the evidence for or against the Hubble Tension. These efforts include: new, higher signal-to-noise distance measurements from JWST, investigations into the differing treatment of nearby SNe, and the calibration of a new methodology for SN distance measurement twice as precise and accurate as the canonical approach. These paths together will ensure a more complete understanding of the Hubble Tension, its significance (e.g., H0 tails), and will prove crucial in ushering the accuracy of local H0 measurements into the regime of precision cosmology.
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https://lbnl.zoom.us/j/98854322464?pwd=K2tKUm1VZjRlV1J5RHE3cXdHQzRxdz09
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