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Browsing by Subject "BL Lacertae objects: general"

Browsing by Subject "BL Lacertae objects: general"

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  • Correlation between optical and γ-ray flux variations in BL Lacs 
    Rajput, Bhoomika; Shah, Zahir; Stalin, C. S; Sahayanathan, S; Rakshit, S (Oxford University Press on behalf of the Royal Astronomical Society, 2021-06)
    We report here results of the analysis of correlated flux variations between the optical and GeV γ-ray bands in three bright BL Lac objects, namely AO 0235+164, OJ 287, and PKS 2155−304. This was based on the analysis of ...
  • Detection of minute-timescale γ-ray variability in BL Lacertae by Fermi-LAT 
    Pandey, Ashwani; Stalin, C. S (EDP Sciences, 2022-12)
    BL Lacertae, the prototype of the BL Lacertae (BL Lac) category of blazars, underwent a giant γ-ray flare in April 2021. The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (hereafter Fermi-LAT) ...
  • Does black hole spin play a key role in the FSRQ/BL Lac dichotomy? 
    Bhattacharya, D; Sreekumar, P; Mukhopadhyay, B; Tomar, I (IOP Publishing, 2016-04)
    Blazars are characterized by large intensity and spectral v ariations across the electromagnetic spectrum It is believed that jets emerging from them are almo st aligned with the line-of-sight. The major- ity of ...
  • Evidence of underdeveloped torus and broad-line region of weak emission line quasars based on their spectral energy distribution 
    Kumar, Ritish; Chand, Hum; Joshi, Ravi (Oxford University Press on behalf of Royal Astronomical Society, 2023-03)
    To unravel the dominant cause of the weak emission line in a subset of optically selected radio-quiet 'weak emission line quasars' (WLQs), we have investigated the possibility of an underdeveloped broad line region (BLR). ...
  • From nearby low luminosity AGN to High Redshift Radio Galaxies: science interests with square kilometre array 
    Kharb, P; Lal, D. V; Singh, V; Bagchi, J; Ishwara-Chandra, C. H; Hota, A; Konar, C; Wadadekar, Yogesh; Shastri, P; Mousumi Das; Baliyan, K; Nath, B. B; M. Pandey-Pommier (Springer, 2016-12)
    We present detailed science cases that a large fraction of the Indian AGN community is interested in pursuing with the upcoming Square Kilometre Array (SKA). These interests range from understanding low luminosity active ...
  • Host galaxy magnitude of OJ 287 from its colours at minimum light 
    Valtonen, Mauri J; Dey, Lankeswar; Zola, S; Ciprini, S; Kidger, M; Pursimo, T; Gopakumar, A; Matsumoto, K; Sadakane, K; Caton, D. B; Nilsson, K; Komossa, S; Bagaglia, M; Baransky, A; Boumis, P; Boyd, D; Castro-Tirado, A. J; Debski, B; Drozdz, M; Perez, A. Escartin; Fiorucci, M; Garcia, F; Gazeas, K; Ghosh, S; Godunova, V; Gomez, J. L; Gredel, R; Grupe, D; Haislip, J. B; Henning, T; Hurst, G; Janík, J; Kouprianov, V. V; Lehto, H; Liakos, A; Mathur, S; Mugrauer, M; Nogues, R. Naves; Nucciarelli, G; Ogloza, W; Ojha, D. K; Pajdosz-Śmierciak, U; Pascolini, S; Poyner, G; Reichart, D. E; Rizzi, N; Roncella, F; Sahu, D. K; Sillanpää, A; Simon, A; Siwak, M; Alfaro, F. C. Soldán; Sonbas, E; Tosti, G; Vasylenko, V; Webb, J. R; Zielinski, P (Oxford University Press on behalf of Royal Astronomical Society, 2022-08)
    OJ 287 is a BL Lacertae type quasar in which the active galactic nucleus (AGN) outshines the host galaxy by an order of magnitude. The only exception to this may be at minimum light when the AGN activity is so low that ...
  • Intranight optical variability of blazars and radio-quiet quasars using the ZTF survey 
    Negi, Vibhore; Gopal-Krishna; Joshi, Ravi; Chand, Hum; Wiita, Paul J; Navaneeth, P. K; Singh, Ravi S (Oxford University Press on behalf of Royal Astronomical Society, 2023-07)
    We explore the potential of the ongoing Zwicky Transient Facility (ZTF) survey for studying intranight optical variability (INOV) of active galactic nuclei (AGNs), in particular for picking rare events of large INOV ...
  • Kinematics of and emission from helically orbiting blobs in a relativistic magnetized jet 
    Mohan, Prashanth; Mangalam, A (IOP Publishing, 2015-07-01)
    We present a general relativistic (GR) model of jet variability in active galactic nuclei due to orbiting blobs in helical motion along a funnel or cone-shaped magnetic surface anchored to the accretion disk near the black ...
  • Long term γ-ray variability of blazars 
    Rajput, Bhoomika; Stalin, C. S; Rakshit, S (EDP Sciences, 2020-02)
    We used the data from the Fermi Gamma-ray Space Telescope to characterise the γ-ray flux variability of blazars on month-like time scales. Our sample consists of 1120 blazars of which 481 are flat spectrum radio quasars ...
  • Long-term optical and infrared variability characteristics of Fermi blazars 
    Safna, P. Z; Stalin, C. S; Rakshit, S; Mathew, Blesson (Oxford University Press on behalf of the Royal Astronomical Society, 2020-11)
    We present long-term optical and near-infrared flux variability analysis of 37 blazars detected in the γ-ray band by the Fermi Gamma-Ray Space Telescope. Among them, 30 are flat spectrum radio quasars (FSRQs) and 7 are BL ...
  • Mid-infrared variability of γ-ray emitting blazars 
    Anjum, A; Stalin, C. S; Rakshit, S; Gudennavar, S. B; Durgapal, A (Oxford University Press on behalf of the Royal Astronomical Society, 2020-05)
    Using data from the Wide-field Infrared Survey Explorer, we studied the mid-infrared (mid-IR) 3.4 μm (W1-band) and 4.6 μm (W2-band) flux variability of γ-ray emitting blazars. Our sample consists of 460 flat spectrum radio ...
  • Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse timescales 
    Agarwal, A; Mihov, B; Andruchow, I; Cellone, S. A; Anupama, G. C; Agrawal, V; Zola, S; Slavcheva, L; Slavcheva-Mihova, L; Ozdonmez, A; Ege, Ergun; Raj, A; Mammana, L; Zibecchi, L; Fernandez-Lajus, E (EDP Sciences, 2021-01)
    Context. The TeV BL Lac object PG 1553+113 is one of the primary candidates for a binary supermassive black hole system. Aims. We study the flux and spectral variability of PG 1553+113 on intra-night to long-term ...
  • Multi-epoch intranight optical monitoring of eight radio-quiet BL Lac candidates 
    Kumar, P; Gopal-Krishna; Stalin, C. S; Chand, H; Srianand, R; Petitjean, P (Oxford University Press on behalf of the Royal Astronomical Society, 2017-10)
    For a new sample of eight 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 ...
  • Multiband optical variability of 3C 279 on diverse time scales 
    Aditi Agarwal; Cellone, Sergio A; Andruchow, I; Mammana, Luis; Singh, Mridweeka; Anupama, G. C; Mihov, B; Raj, A; eva-Mihova, L; Ozdonmez, Aykut; Ege, Ergun (Oxford University Press on behalf of the Royal Astronomical Society, 2019-09)
    We have monitored the flat spectrum radio quasar, 3C 279, in the optical B, V, R, and I passbands from 2018 February to 2018 July for 24 nights, with a total of 716 frames, to study flux, colour, and spectral variability ...
  • Multiband optical variability of 3C 279 on diverse time-scales 
    Agarwal, A; Cellone, S. A; Andruchow, Ileana; Mammana, Luis; Mridweeka Singh; Anupama, G. C; Mihov, B; Raj, A; Slavcheva-Mihova, L; Ozdonmez, Aykut; Ege, Ergun (Oxford University Press on behalf of the Royal Astronomical Society, 2019-09)
    We have monitored the flat spectrum radio quasar, 3C 279, in the optical B, V, R, and I passbands from 2018 February to 2018 July for 24 nights, with a total of 716 frames, to study flux, colour, and spectral variability ...
  • Multiwavelength intraday variability of the BL Lacertae S5 0716+714 
    Gupta, A. C; Krichbaum, T. P; Wiita, P. J; Rani, B; Sokolovsky, K. V; Mohan, Prashanth; Mangalam, A; Marchili, N; Fuhrmann, L; Agudo, I; Bach, U; Bachev, R; Böttcher, M; Gabanyi, K. E; Gaur, H; Hawkins, K; Kimeridze, G. N; Kurtanidze, O. M; Kurtanidze, S. O; Lee, C.-U; Liu, X; McBreen, B; Nesci, R; Nestoras, G; Nikolashvili, M. G; Ohlert, J. M; Palma, N; Peneva, S; Pursimo, T; Semkov, E; Strigachev, A; Webb, J. R; Wiesemeyer, H; Zensus, J. A (Wiley-Blackwell, 2012-09)
    We report results from a one-week multiwavelength campaign to monitor the BL Lacertae object (BL Lac) S5 0716+714 (on 2009 December 9–16). Nine ground-based telescopes at widely separated longitudes and one space-based ...
  • A multiwavelength study of three hybrid blazars 
    Stanley, E. C; Kharb, P; Lister, M. L; Marshall, H. L; O'Dea, C; Baum, S (IOP Publishing, 2015-07-01)
    We present multiwavelength imaging observations of PKS 1045−188, 8C 1849+670, and PKS 2216−038, three radio-loud active galactic nuclei from the MOJAVE-Chandra Sample that straddle the Fanaroff-Riley (FR) boundary between ...
  • Optical flux and colour variability of blazars in the ZTF survey 
    Negi, Vibhore; Joshi, Ravi; Chand, Krishan; Chand, Hum; Wiita, Paul; Ho, Luis C; Singh, Ravi S (Oxford University Press on behalf of Royal Astronomical Society, 2022-02)
    We investigate the temporal and colour variability of 897 blazars, comprising 455 BL Lacertae objects (BL Lacs) and 442 Flat Spectrum Radio Quasars (FSRQs), selected from the Roma-BZCAT catalogue, using the multiband light ...
  • A peculiar multiwavelength flare in the blazar 3C 454.3 
    Gupta, A. C; Mangalam, A; Wiita, J. Paul; Kushwaha, P; Gaur, H; Zhang, H; Gu, M. F; Liao, M; Dewangan, G. C; Ho, L. C; Mohan, P; Umeura, M; Sasada, M; Volvach, A. E; Agarwal, A; Aller, M. F; Aller, H. D; Bachev, R; Lahteenmaki, A; Semkov, E; Strigachev, A; Tornikoski, M; Volvach, L. N (Oxford University Press on behalf of the Royal Astronomical Society, 2017-11)
    The blazar 3C 454.3 exhibited a strong flare seen in γ -rays, X-rays and optical/near-infrared bands during 2009 December 3–12. Emission in the V and J bands rose more gradually than did the γ -rays and soft X-rays, ...
  • Polarimetric and spectroscopic study of radio quiet weak emission line quasars 
    Kumar, P; Chand, H; Srianand, R; Stalin, C. S; Petitjean, P; Gopal-Krishna (Oxford University Press on behalf of the Royal Astronomical Society, 2018-10)
    A small subset of optically selected radio-quiet quasars showing weak or no emission lines may turn out to be the elusive radio-quiet BL Lac objects, or simply be radio-quiet QSOs with a still-forming/shielded broad line ...

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