32 research outputs found
Multi-color optical monitoring of the quasar 3C 273 from 2005 to 2016
We have monitored the quasar 3C 273 in optical , and bands from
2005 to 2016. Intraday variability (IDV) is detected on seven nights. The
variability amplitudes for most of nights are less than 10\% and four nights
more than 20\%. When considering the nights with time spans hours, the
value of duty cycle (DC) is 14.17 per cent. Over the twelve years, the overall
magnitude and color index variabilities are ,
, , and
respectively. The largest clear IDV has an
amplitude of 42% over just 5.8 minutes and the weakest detected IDV is 5.4%
over 175 minutes. The BWB (bluer when brighter) chromatic trend is dominant for
3C 273 and appears at different flux levels on intraday timescales. The BWB
trend exists for short-term timescales and intermediate-term timescales but
different timescales have different correlations. There is no BWB trend for our
whole time-series data sets. A significant anti-correlation between BWB trend
and length of timescales is found. Combining with -band data from previous
works, we find a possible quasi-periodicity of days. The
possible explanations for the observed variability, BWB chromatic trend and
periodicity are discussed.Comment: 63 pages, 11 figures, 6 tables. Accepted for publication in ApJ