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Related papers: Intranight optical variability of Blazars

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We present the results of a comparative study of the intra-night optical variability (INOV) characteristics of radio-loud and radio-quiet quasars, which involves a systematic intra-night optical monitoring of seven sets of high luminosity…

Astrophysics · Physics 2009-11-10 C. S. Stalin , Gopal-Krishna , Ram Sagar , Paul J. Wiita

We report optical monitoring observations of 20 high-luminosity AGN, 12 of which are radio-quiet quasars (RQQs). Intra-night optical variability (INOV) was detected for 13 of the 20 objects, including 5 RQQs. The variations are distinctly…

Astrophysics · Physics 2009-11-10 C. S. Stalin , A. C. Gupta , Gopal-Krishna , P. J. Wiita , R. Sagar

We present results of a programme of multi-epoch, intra-night optical monitoring of a sample of non-blazar type AGN, which includes seven radio-quiet QSOs (RQQs) and an equal number of radio-loud, lobe-dominated quasars (LDQs), covering a…

Astrophysics · Physics 2009-11-10 C. S. Stalin , Gopal-Krishna , Ram Sagar , Paul J. Wiita

We report the results of our intensive intranight optical monitoring of 8 `radio-intermediate quasars' (RIQs) having flat or inverted radio spectra. The monitoring was carried out in {\it R-} band on 25 nights during 2005-09. An intranight…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Arti Goyal , Gopal-Krishna , S. Joshi , R. Sagar , Paul J. Wiita , G. C. Anupama , D. K. Sahu

This is continuation of our search for the elusive radio-quiet blazars, by carrying out a systematic programme to detect intranight optical variability (INOV) in a subset of `Weak-Lines-Quasars' (WLQs) which are designated as `high…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Hum Chand , Parveen Kumar , Gopal-Krishna

We report an extension of our program to search for radio-quiet BL Lac candidates using intra-night optical variability (INOV) as a probe. The present INOV observations cover a well-defined representative set of 10 `radio-quiet…

High Energy Astrophysical Phenomena · Physics 2016-07-27 Parveen Kumar , Hum Chand , Gopal-Krishna

{Abridged} Rapid variations in optical flux are seen in many quasars and all blazars. The amount of variability in different classes of Active Galactic Nuclei has been studied extensively but many questions remain unanswered. We present the…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Arti Goyal , Gopal-Krishna , Paul J. Wiita , G. C. Anupama , D. K. Sahu , R. Sagar , S. Joshi

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 Energy Astrophysical Phenomena · Physics 2015-06-23 Parveen Kumar , Gopal-Krishna , Hum Chand

Although well established for BL Lac objects and radio-loud quasars, the occurrence of intra-night optical variability (INOV) in radio-quiet quasars is still debated, primarily since only a handful of INOV events with good statistical…

Astrophysics · Physics 2007-06-01 A. Goyal , Gopal-Krishna , Ram Sagar , G. C. Anupama , D. K. Sahu

Based on a recently started programme, we report the first search for intranight optical variability among radio-quiet weak-line-quasars (RQWLQs). Eight members of this class were observed on 13 nights in the R-band, such that each source…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-08 Gopal-Krishna , Ravi Joshi , Hum Chand

In this first systematic attempt to characterise the intranight optical variability (INOV) of TeV detected blazars, we have monitored a well defined set of 9 TeV blazars on total 26 nights during 2004-2010. In this R (or V)-band monitoring…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Gopal-Krishna , Arti Goyal , S. Joshi , Chrisphin Karthick , R. Sagar , Paul J. Wiita , G. C. Anupama , D. K. Sahu

For a new sample of 8 weak-line-quasars (WLQs) we report a sensitive search in 20 intranight monitoring sessions, for blazar-like optical flux variations on hour-like and longer time scale (day/month/year$-$like). The sample consists…

High Energy Astrophysical Phenomena · Physics 2017-09-20 P. Kumar , Gopal-Krishna , C. S. Stalin , H. Chand , R. Srianand , P. Petitjean

We report the first results obtained from our campaign to characterize the intranight-optical variability (INOV) properties of {\it Fermi}~detected blazars, using the observations from the recently commissioned 1.3 m J C Bhattacharya…

High Energy Astrophysical Phenomena · Physics 2018-12-31 Vaidehi S. Paliya , C. S. Stalin , M. Ajello , A. Kaur

The incidence of intra-night optical variability (INOV) is known to to differ significantly among different classes of powerful active galactic nuclei (AGN). A number of statistical methods have been employed in the literature for testing…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Arti Goyal , Gopal-Krishna , Paul J. Wiita , C. S. Stalin , Ram Sagar

We explore the potential of the ongoing Zwicky-Transient-Facility (ZTF) survey for studying Intra-Night Optical Variability (INOV) of active galactic nuclei (AGN), in particular for picking rare events of large INOV amplitudes, whose…

Astrophysics of Galaxies · Physics 2023-05-03 Vibhore Negi , Gopal-Krishna , Ravi Joshi , Hum Chand , Paul Wiita , Navaneeth P K , Ravi S. Singh

We present the results obtained from our campaign to characterize the intra-night-optical variability properties of blazars detected by the {\it Fermi} Large Area Telescope. This involves R-band monitoring observations of a sample of 18…

High Energy Astrophysical Phenomena · Physics 2022-02-16 K. Subbu Ulaganatha Pandian , A. Natarajan , C. S. Stalin , Ashwani Pandey , S. Muneer , B. Natarajan

This overview provides a historical perspective highlighting the pioneering role which the fairly modest observational facilities of ARIES have played since the 1990s in systematically characterizing the optical variability on hour-like…

Astrophysics of Galaxies · Physics 2017-11-16 Gopal-Krishna , Paul J. Wiita

We report the first study to characterise intranight variability of the blazar class from the perspective of (rest-frame) UV emission. For this, we carried out intranight optical monitoring of 14 flat-spectrum radio quasars (FSRQs) located…

Astrophysics of Galaxies · Physics 2022-01-02 Krishan Chand , Gopal-Krishna , Amitesh Omar , Hum Chand , Sapna Mishra , P. S. Bisht , S. Britzen

We present the result of our extensive intranight optical monitoring of the well known low-energy peaked BL Lac (LBL) object PKS 0735+178. This long-term follow-up consists of $R$-band monitoring for a minimum duration of $\sim 4$ hours, on…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Arti Goyal , Gopal-Krishna , G. C. Anupama , D. K. Sahu , R. Sagar , S. Britzen , M. Karouzos , M. F. Aller , H. D. Aller

In this paper we present results of a short-term optical monitoring of 13 blazars. The objects were monitored mostly in the R-band for a total of ~ 160 hours between 2006 and 2011. We study the nature of the short-term variations and show…

High Energy Astrophysical Phenomena · Physics 2013-11-21 R. Bachev , E. Semkov , A. Strigachev , Alok C. Gupta , Haritma Gaur , B. Mihov , S. Boeva , L. Slavcheva-Mihova
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