A New Analysis of the Medium-Timescale Periodicity in S5 0716+714

Abstract

In this paper, we have collected the available observation data of BL Lac S5 0716+714 in I-band from published literature during 1994 to 2000. The light curve shows S5 0716+714 is very active and very complicated non-sinusoidal variations. We studied its mediumtimescale periodicity using the Jurkevich and power spectrum method to search for the possible medium-timescale periods and found that one possible medium-timescale periodic with a period of around 14±0.1 day is obtained for S5 0716+714. It is interesting to note that these results are in good agreement with the previous results by Impey et al. (2000) and Qian et al. (2002), and this work provides a new analysis and evidence of the medium-timescale periodicity in BL Lac S5 0716+714. The helical jet model seems to be more reasonable for explaining our results than other models.

The Radio and $γ$-ray Variability Analysis of S5 0716+714

“…This is also agreement with the timescale P γ = 344.0 ± 16.4 days obtained by us. However, there are no obvious signs of 1-7, 4, 10, 14, 24 days, 3.3 and 5.5-6 years period in our results (Quirrenbach et al 1991;Qian et al 2002;Ma et al 2004;Raiteri et al 2003;Yuan et al 2017). For the timescale of 3.3 and 5.5-6 years obtained by Raiteri et al (2003), the duration of the data train used in the paper is too short to confirm them (Kidger et al 1992).…”

“…The foregoing analysis suggests that there is a tentative variability periodicity on timescale P 15GHz = 266.0 ± 11.5 and P γ = 344.0 ± 16.4 days in the radio 15 GHz, and γ-ray datasets of S5 0716+714, respectively. The variability of S5 0716+714 was studied in many literatures (Quirrenbach et al 1991;Qian et al 2002;Ma et al 2004;Rani et al 2013;Wiita et al 2009;Liao et al 2014;Raiteri et al 2003). They found that there are various timescales from 1 days to several years in the light curves of the object.…”

“…Based on the 5.3 years optical monitoring, Qian et al (2002) detected a cycle of 10 days. A periodicity about 14 days in I band was obtained by Ma et al (2004). Yuan et al (2017) have monitored and analyzed the optical variability of S5 0716+714.…”

A Periodicity Analysis of the Light Curve of 3C 454.3

“…Observations also show that some sources exhibit medium-time scale variability on time scales of weeks or months. Impey et al (2000) claimed that PKS 0716+714 likely has a periodic variation on time scales of about 10 days and Ma et al (2004) found that PKS 0716+714 has a variability period of 14 ± 0.1 days by using Jurkevich's method (1971a) and power spectrum analysis. Lainela et al (1999) and Katajainen et al (2000) have obtained a variability period about 65 days for 3C 66A and Xie et al (2002a) also found that 3C 66A has a variability period of 63 ± 5 days.…”

The long-term optical behavior of BL Lac object S5 0716+714

“…Qian et al also found evidence of quasi-periodic oscillations in their observations, and there may be a period on the order of 10 days in its light curve [24]. Ma et al obtained one possible medium-timescale variation with a period of around 14 days [25]. Raiteri et al found there may be an oscillation on a 3.3 year time scale in the R band light curve [26].…”