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Astrophysics Luncheon Seminar

Increased Hubble Tension with a New Measurement of the Hubble Constant using Strong Lensing
Presented by Anowar Shajib
University of California, Los Angeles

Monday, November 18, 2019
12:00 noon in 169-336

The recent tension between early- and late-Universe measurements of the Hubble constant highlights the necessity for independent and precise probes such as the time-delay cosmography. The measured time-delays between the lensed images of a background quasar depend on the absolute physical scales in the lens configuration. Thus, they allow measurement of these scales to infer the Hubble constant, H0. Due to a number of great advancements over the past decade in both the data quality and modeling techniques, the measurement of H0 from the time-delays has already become competitive with other traditional methods such as the cosmic distance ladder. This is evident from the recent 2.4% blind measurement of H0 from only six lenses (Wong et al. 2019). Recently, I have analyzed one new lens system to infer H0 with the highest precision from a single lens system to date. This new measurement brings the combined uncertainty from time-delay cosmography to 2%, which is comparable to the SH0ES measurement-and increases the tension with the early-Universe probes. Lastly, I will present the future roadmap of time-delay cosmography to independently reach 1% precision within a few years.

JPL Contact: Jacqueline McCleary (3-4619)

SVCP Astrophysics

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