2000/07/11 by I. Burud, J. Hjorth, A. O. Jaunsen +9 · 5 citations
Earth and Planetary Sciences · Physics and Astronomy · #Adaptive optics and wavefront sensing #Geophysics and Gravity Measurements #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1086/317213
published as Astrophys.J. 544 (2000) 117-122 · 15 pages, 4 figures, accepted for publication in ApJ
arxiv created 2000/07/11 · openalex publication_date 2000/11/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We present optical I -band light curves of the gravitationally lensed double QSO B1600+434 from observations obtained at the Nordic Optical Telescope (NOT) between 1998 April and 1999 November. The photometry has been performed by simultaneous deconvolution of all the data frames, involving a numerical lens galaxy model. Four methods have been applied to determine the time delay between the two QSO components, giving a mean estimate of Δ t = 51 ± 4 days (95% confidence level). This is the fourth optical time delay ever measured. Adopting a Ω = 0.3, Λ = 0 universe and using the mass model of Maller et al., this time delay estimate yields a Hubble parameter of H 0 = 52 km s -1 Mpc -1 (95% confidence level), where the errors include time delay as well as model uncertainties. There are time-dependent offsets between the two (appropriately shifted) light curves that indicate the presence of external variations due to microlensing.