Abstract Details

Name: VINEET OJHA
Affiliation: Aryabhatta Research Institute of Observational Sciences (ARIES)
Conference ID: ASI2021_505
Title : Comparative intranight optical variability study of radio-loud narrow-line Seyfert 1 galaxies with and without radio jets
Authors and Co-Authors : Vineet Ojha (Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital - 263002, India), Vivek Jha (Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital - 263002, India), Gopal-Krishna (UM-DAE Centre for Excellence in Basic Sciences, Vidyanagari, Mumbai-400098, India), Hum Chand (Department of Physics and Astronomical Sciences, Central University of Himachal Pradesh (CUHP), Dharamshala−176215, India)
Abstract Type : Oral
Abstract Category : Extragalactic Astronomy
Abstract : To establish stronger intranight optical variability (INOV) with high duty cycle (DC) as evidence of the presence of jet in an AGN, a direct approach has been pursued by carrying out a first comparative INOV study of two samples of radio-loud narrow-line Seyfert 1 galaxies (RLNLSy1s) with and without radio jets, confirmed based upon their Very Long Baseline Array (VLBA) observations. Our unbiased sample consists of 15 and 8 RLNLSy1s with the presence and absence of radio jets, respectively. We have monitored these two sets of RLNLSy1s in 37 and 16 sessions of a minimum of 3.0 hours duration each. The INOV duty cycles for these two sets are found to be 41% and 20%, respectively for a typical INOV amplitude ($\psi$) detection threshold of > 3%. The higher DC of the jetted-RLNLSy1s sample in comparison to the sample of non-jetted-RLNLSy1s supports the scenario that jetted-AGN are more amenable to show INOV, thus INOV detections with higher INOV DC can be used as indirect evidence of the presence of jet even also in the case of low-luminous high accreting AGNs such as NLSy1s in which dilution of the AGN's nonthermal optical emission by the (much steadier) optical emission contributed the nuclear accretion disc is quite likely. We have detected an unexpected remarkable flare in a non-jetted-RLNLSy1 galaxy, J163401.94+480940.2, whose rapid brightening phase is shown to imply a minute like doubling time of ~ 22 minutes, thereby approaching to the extremely fast minute like variability, observed from FSRQ PKS 1222+21 at 400 GeV.