SIMBAD references

Using the 1.56 m telescope at Shanghai Observatory, China, we present the photometric results of 1ES 1959+650, which cover from 2006 June 11 to 2014 July 31. The maximum variabilities are Δm_V/max = 1.74 ± 0.02 mag in the V band, Δm_R/max = 0.97 ± 0.02 mag in the R band, and Δm_T/max = 1.15 ± 0.03 mag in the I band. During the monitoring period, we obtain intraday variabilities on 2009 September 2 (JD 2455077) and 2009 September 3 (JD 2455078). On 2009 September 2, the intraday variabilities are Δm_V = 0.36 ± 0.08 mag within 1.56 hr, Δm_R = 0.21 ± 0.04 mag within 23 minutes, and Δm_I = 0.53 ± 0.03 mag within 45 minutes. On 2009 September 3, the intraday variabilities are Δm_V = 0.40 ± 0.10 mag within 27 minutes, Δm_R = 0.48 ± 0.04 mag within 3.24 hr, and Δm_I = 0.68 ± 0.06 mag within 3.72 hr. The two intraday variabilities occur in 24 hr, which may occur in the same variable phase. Other results show that (1) no quasi-periodicity is found in the long-term light curve and (2) the correlations between the brightness and the spectrum show obvious anti-correlation, α = -(0.18 ± 0.02)F_V + (2.33 ± 0.12), with the correlation coefficient r = -0.74 and the chance probability p < 0.01%.