HQM - Hamburg Quasar Monitoring
The Hamburg Quasar Monitoring Programm (HQM) has been performed between 1988 and 1995. Later follow-up observations in 1996, 1998, 2000 and 2001 as well as some earlier data between 1984 and 1986 from previous projects enlarged the overall sample time for some of our targets up to 15 years. The HQM sample contains lightcurves for roughly 500 quasars, in total about 35.000 individual datapoints, although the main target list is much shorter - around 300 targets.
The original purpose of HQMwas the detection of high amplification events in quasar lighcurves lensed by an unknown foreground galaxy. An intensive monitoring of quasars is as well a presentation of intrinsic quasar variability. Although this was not the primary goal for HQM, several quasars became members of the main target list from collaborations with other observers whos first interests were quasar physics.
HQM was designed to create a large quantity of lightcurves of Quasars and AGN. In the beginning we had been a little too enthusiastic. We thought a large and carefully selected sample, a good analysis program and five years time would produce a at least few High Amplification Events. The longer HQM was running the more it became evident that the key would either be a larger and much denser observed sample or a sample to do statistical evaluations. At the end in 1995 we had a great list of quasars and numbers of datapoints and lightcurves but all we had not was a complete sample.
Several influences destroid our original goals during the eight years that HQM run between 1988 and 1995. Why has our sample became so inhomogenous?
All in all a large list of targets with sometimes very good resolved lightcurves was observed but the discussion of the sample as originated in 1988 was not possible.
But we had been chasing microlensing events in quasar lightcurves and non (except some in multiple imaged quasars like the double quasar 0957+561 or the Einstein cross 2237+0305) had been found. In all of our lightcurves we see a large variety of variability but a definite microlensing event feature was not between the data.
On the other hand we cannot exclude Microlensing Events.
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contact: Jochen Schramm, Hamburger Sternwarte