Intranight Optical Variability of Radio-Quiet Weak Emission Line Quasars-III

Abstract

This is continuation of our programme to search for the elusive radio-quiet BL Lacs, by carrying out a systematic search for intranight optical variability (INOV) in a subset of `weak-line quasars' which are already designated as `high-confidence BL Lac candidate' and are also known to be radio-quiet. For 6 such radio-quiet weak-line quasars (RQWLQs), we present here new INOV observations taken in 11 sessions of duration >3 hours each. Combining these data with our previously published INOV monitoring of RQWLQs in 19 sessions yields INOV observations for a set of 15 RQWLQs monitored in 30 sessions, each lasting more than 3 hours. The 30 differential light curves, thus obtained for the 15 RQWLQs, were subjected to a statistical analysis using the F-test, and the deduced INOV characteristics of the RQWLQs then compared with those published recently for several prominent AGN classes, also applying the F-test. From our existing INOV observations, there is a hint that RQWLQs in our sample show a significantly higher INOV duty cycle than radio-quiet quasars and radio lobe-dominated quasars. Two sessions when we have detected strong (blazar-like) INOV for RQWLQs are pointed out, and these two RQWLQs are therefore the best known candidates for radio-quiet BL Lacs, deserving to be pursued. For a proper comparison with the INOV properties already established for (brighter) members of several prominent classes of AGN, a factor of 2-3 improvement in the INOV detection threshold for the RQWLQs is needed and it would be very interesting to check if that would yield a significantly higher estimate for INOV duty cycle than is found here.

9 pages, 1 figure and 4 tables, accepted for publication in MNRAS main journal. arXiv admin note: text overlap with arXiv:1212.5384, arXiv:1403.7440

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Cited by in corpus (9)

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• Evidence of under-developed torus and broad-line region of weak emission line quasars based on their spectral energy distribution
• Super-Eddington accretion in the Q2237+0305 quasar?
• Intranight optical variability of radio-quiet BL Lacertae objects
• Intra-night optical variability and radio characteristics of extremely radio-loud narrow-line Seyfert 1 galaxies
• Evidence of jet induced optical microvariability in radio-loud Narrow Line Seyfert 1 Galaxies
• Intra-night optical variability study of a non-jetted narrow-line Seyfert 1 galaxy: SDSS J163401.94+480940.1
• The shortest detected intra-day variability of active galactic nuclei in TESS survey