The long-term variability of BL Lac object PKS 0735+178

¹ CCAST(World Laboratory), P.O. BOX 8730, Beijing, China
² Center for Astrophysics, Guangzhou Normal University, Guangzhou 510400, China
³ Joint Laboratory for Optical Astronomy, Chinese Academy of Sciences, China
⁴ Yunnan Observatory, Chinese Academy of Sciences, China
⁵ Department of Physics, Yunnan Normal University, Kunming, China

Send offprint request to: J.H. Fan

Received: 14 June 1996
Accepted: 31 January 1997

Abstract

The long-term variability of PKS 0735+178 in B band is shown with some new data presented and discussed by means of Jurkevich's method. The results show with good possibility the presence of a period of 14.2 years. The period of 4.89 years found by Webb et al. (1988) and Smith et al. (1987) might be confirmed with more observations, and their period of 1.2 years can be ruled out.