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Activity Number: 222 - Statistical Challenges with Astronomical Data
Type: Invited
Date/Time: Monday, July 29, 2019 : 2:00 PM to 3:50 PM
Sponsor: National Institute of Statistical Sciences
Abstract #300452 Presentation
Title: Time Delay Cosmography Towards the Hubble Constant
Author(s): Hyungsuk Tak* and Simon Birrer?
Companies: University of Notre Dame and University of California, Los Angeles
Keywords: Astrostatistics; cosmology; physical sciences; time series; image data
Abstract:

The Hubble constant is a core cosmological parameter that represents the current expansion rate of the Universe. However, its estimates have been inconsistent. Astronomers have been concerned about this inconsistency, developing various estimation methods independently, such as time delay cosmography. This method is based on strong gravitational lensing, an effect that multiple images of the same astronomical object appear in the sky because paths of the images (from the object to the Earth) are bent by the strong gravitational field of an intervening galaxy. This strong gravitational lensing produces two types of the data; multiple time series data of brightness, and image data of lensing galaxy and lensed images. We use the time series data to infer time delays between the arrival times of the multiply-lensed images, and the image data to estimate gravitational potential of the lensing galaxy. The Hubble constant can be estimated with these quantities. Also, I explain the relationship among these three components, i.e., time delays, gravitational potential, and the Hubble constant, introducing data analytic challenges and our collaborative efforts to overcome these challenges.


Authors who are presenting talks have a * after their name.

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