Time delays in PG1115+080: new estimates

TL;DR

This paper presents new measurements of time delays in the gravitational lens PG1115+080, which could lead to more accurate estimates of the Hubble constant by reducing discrepancies with other measurement methods.

Contribution

It provides updated time delay estimates based on recent monitoring data, improving the precision of gravitational lensing measurements for cosmological purposes.

Findings

New time delays: 16.4 and 12 days for specific image pairs.

Previous estimates were 23.7/9.4 and 25/13.3 days, respectively.

Updated delays may lead to higher Hubble constant estimates.

Abstract

We report new estimates of the time delays in the quadruple gravitationally lensed quasar PG1115+080, obtained from the monitoring data in filter R with the 1.5-m telescope at the Maidanak Mountain (Uzbekistan, Central Asia) in 2004-2006. The time delays are 16.4 days between images C and B, and 12 days between C and A1+A2, with image C being leading for both pairs. The only known estimates of the time delays in PG1115 are those based on observations by Schechter et al. (1997) -- 23.7 and 9.4 days between images C and B, C and A1+A2, respectively, as calculated by Schechter et al., and 25 and 13.3 days as revised by Barkana (1997) for the same image components with the use of another method. The new values of time delays in PG 1115+080 may be expected to provide larger estimates of the Hubble constant thus decreasing a diversity between the H_0 estimates taken from gravitationally lensed quasars and with other methods.