The Hamburg quasar monitoring program (HQM) at Calar Alto. III. Lightcurves of optically violent variable sources
Abstract
HQM is an optical broad-band photometric monitoring program carried out since September 1988. We use a CCD camera at the MPIA 1.2 m telescope. Fully automatic photometric reduction relative to stars in the frames is done within a few minutes after each exposure, thus interesting brightness changes can be followed in detail. The typical photometric error is 1-2% for a 17.5 mag quasar. We here present lightcurves of 14 known violently variable sources and compare them with literature data. For two BL Lac objects, 1E 1229+645 and 4C 56.27 (1823+568), this paper is the first variability study. We have also carried out POSS photometry to obtain indications for variability on a longer timescale.
- Publication:
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Astronomy and Astrophysics Supplement Series
- Pub Date:
- August 1994
- Bibcode:
- 1994A&AS..106..349S
- Keywords:
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- QUASARS: GENERAL