Intra-night optical variability of γ −ray detected narrow-line Seyfert1 galaxies

Ojha, Vineet; Chand, Hum; Gopal-Krishna, Gopal-Krishna

doi:10.1093/mnras/staa3937

Cited by 4 publications

(8 citation statements)

References 49 publications

(8 reference statements)

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“…The chance of a false INOV detection signal becomes lower for a smaller value of α. Therefore, in the present work, similar to our previous work, two critical significance levels, α = 0.01 and α = 0.05 are set by us (e.g., see Ojha et al 2021). Following Ojha et al (2021), a NLSy1 is designated as variable for a given session according to this test if the computed value of F η is found to be greater than its F c (0.99).…”

Section: Data Reductionmentioning

confidence: 96%

“…5. Nonetheless, bearing the above in mind, we have chosen an aperture radius equal to 2×FWHM for our final analysis, as already elaborated in Ojha et al (2021).…”

Section: Data Reductionmentioning

confidence: 99%

“…Table 3 lists coordinates together with some other parameters of the steady comparison stars used for all the sessions. It has been shown in Ojha et al (2021) that the color differences of such orders can be safely discounted while analyzing the variability of the DLCs. (Abolfathi et al 2018) has been used for getting optical positions and apparent magnitudes of the sources and their comparison stars.…”

Section: Data Reductionmentioning

confidence: 99%

“…To guarantee the reliability of detection for microvariability events, multi-testing has mostly been used in recent years (e.g., Joshi et al 2011;Goyal et al 2012;de Diego 2014;Ojha et al 2021). Therefore, for unambiguous detection of INOV in a DLC, we have used in the current work two different versions of F-test, which are the standard F-test (hereafter F η -test) and the power-enhanced F-test (hereafter F enh -test).…”

Section: Data Reductionmentioning

confidence: 99%

“…This alternative tool is also used to indirectly verify the presence or absence of jets in other sub-classes of AGN because of the well established observational fact that for radio-loud jet dominated sources such as blazars, both INOV amplitude (ψ) and the duty cycle (DC) are found to be distinctively high in comparison to non-blazars, including weakly polarised flat-radio-spectrum (i.e., radio-beamed) quasars (Goyal et al 2013b;Gopal-Krishna & Wiita 2018). Interestingly, such an indirect tool has been used for a decade in searching for the Doppler boosted optical jets in low luminous AGNs such as NLSy1s and weak emission line QSOs (e.g., see Liu et al 2010;Paliya et al 2013a;Kumar et al 2015;Parveen et al 2016;Kumar et al 2017;Ojha et al 2018Ojha et al , 2021. However, this indirect evidence is based upon the observed high amplitude, and duty cycle of INOV as seen in blazars consisting of strongly Doppler boosted jets.…”

Section: Introductionmentioning

confidence: 99%

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Evidence of jet-induced optical microvariability in radio-loud narrow-line Seyfert 1 galaxies

Ojha

Jha

Chand

et al. 2022

Monthly Notices of the Royal Astronomical Society

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To quantify the role of radio jets for Intra-Night Optical Variability (INOV) in Radio-Loud Narrow-Line Seyfert 1 (RLNLSy1) galaxies, we report the first systematic comparative INOV study of 23 RLNLSy1 galaxies, with 15 RLNLSy1s having confirmed detection of jets (jetted) and the remaining 8 RLNLSy1s having no detection of jets (non-jetted) based on their Very Long Baseline Array observations. We have monitored these two samples, respectively, in 37 and 16 sessions of a minimum 3-hour duration each. Based upon Fη-test at 99% confidence level with a typical INOV amplitude (ψ) detection threshold of > 3%, we find the INOV duty cycles of 12% for the sample of jetted RLNLSy1s, however, none of the sources showed INOV in the sample of non-jetted RLNLSy1s. Among the jetted RLNLSy1s, we find that the Duty Cycle (DC) for jetted γ-ray detected (γ-ray) RLNLSy1s is found to be 34% in contrast to null INOV detection in the case of non-γ-ray RLNLSy1s. It suggests that instead of the mere presence of a jet, relativistic beaming plays a significant role for INOV in the case of low-luminous high accreting AGNs such as NLSy1s in which dilution of the AGN’s non-thermal optical emission by the (much steadier) optical emission contributed by the nuclear accretion disc is quite likely. Our study of jetted γ-ray RLNLSy1s shows more frequent INOV detection for sources with higher apparent jet speed. Further, our results also suggest that among the NLSy1s, only jetted γ-ray RNLSy1 galaxies DC approaches blazar like DC.

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Intra-night optical variability of γ −ray detected narrow-line Seyfert1 galaxies

Cited by 4 publications

References 49 publications

Evidence of jet-induced optical microvariability in radio-loud narrow-line Seyfert 1 galaxies

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