A Robust Determination of the Time Delay in 0957+561A,B and a Measurement of the Global Value of Hubble's Constant
Continued photometric monitoring of the gravitational lens system 0957+561A,B in the g and r bands with the Apache Point Observatory (APO) 3.5 m telescope during 1996 shows a sharp g band event in the trailing (B) image light curve at the precise time predicted in an earlier paper. The prediction was 1 Supported by the Fannie and John Hertz Foundation 2 Currently at the Kitt Peak National Observatory 3 Currently at the Space Telescope Science Institute -- 2 -- based on the observation of the event during 1995 in the leading (A) image and on a differential time delay of 415 days. This success confirms the so called "short delay", and the absence of any such feature at a delay near 540 days rejects the "long delay" for this system, thus resolving a long standing controversy. A series of statistical analyses of our light curve data yield a best fit delay of 417 Sigma 3 days (95% confidence interval) and demonstrate that this result is quite robust against variations in the analysi...
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.