ABSTRACT Strongly lensed explosive transients such as supernovae, gammaray bursts, fast radio bursts, and gravitational waves are very promising tools to determine the Hubble constant (H0) in the near future in addition to strongly lensed quasars. In this work, we show that the transient nature of the point source provides an advantage over quasars: The lensed host galaxy can be observed before or after the transient’s appearance. Therefore, the lens model can be derived from images free of contamination from bright point sources. We quantify this advantage by comparing the precision of a lens model obtained from the same lensesmore »
TDCOSMO: V. Strategies for precise and accurate measurements of the Hubble constant with strong lensing
Strong lensing time delays can measure the Hubble constant H 0 independently of any other probe. Assuming commonly used forms for the radial mass density profile of the lenses, a 2% precision has been achieved with seven TimeDelay Cosmography (TDCOSMO) lenses, in tension with the H 0 from the cosmic microwave background. However, without assumptions on the radial mass density profile – and relying exclusively on stellar kinematics to break the masssheet degeneracy – the precision drops to 8% with the current data obtained using the seven TDCOSMO lenses, which is insufficient to resolve the H 0 tension. With the addition of external information from 33 Sloan Lens ACS (SLACS) lenses, the precision improves to 5% if the deflectors of TDCOSMO and SLACS lenses are drawn from the same population. We investigate the prospect of improving the precision of timedelay cosmography without relying on mass profile assumptions to break the masssheet degeneracy. Our forecasts are based on a previously published hierarchical framework. With existing samples and technology, 3.3% precision on H 0 can be reached by adding spatially resolved kinematics of the seven TDCOSMO lenses. The precision improves to 2.5% with the further addition of kinematics for 50 nontimedelay lenses more »
 Award ID(s):
 1906976
 Publication Date:
 NSFPAR ID:
 10287445
 Journal Name:
 Astronomy & Astrophysics
 Volume:
 649
 Page Range or eLocationID:
 A61
 ISSN:
 00046361
 Sponsoring Org:
 National Science Foundation
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