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Browsing by Author "Joshi, Ravi"

Browsing by Author "Joshi, Ravi"

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  • Accretion disc sizes from continuum reverberation mapping of AGN selected from the ZTF survey 
    Jha, Vivek Kumar; Joshi, Ravi; Chand, Hum; Wu, Xue-Bing; Ho, Luis C; Rastogi, Shantanu; Ma, Qinchun (Oxford University Press on behalf of Royal Astronomical Society, 2022-04)
    We present the accretion disc-size estimates for a sample of 19 active galactic nuclei (AGNs) using the optical g-, r-, and i-band light curves obtained from the Zwicky Transient Facility survey. All the AGNs have reliable ...
  • Appearance versus disappearance of broad absorption line troughs in quasars 
    Mishra, Sapna; Vivek, M; Chand, Hum; Joshi, Ravi (Oxford University Press on behalf of the Royal Astronomical Society, 2021-07)
    We present a new set of 84 broad absorption line (BAL) quasars (1.7 < zem < 4.4) exhibiting an appearance of C IV BAL troughs over 0.3–4.8 rest-frame years by comparing the Sloan Digital Sky Survey Data Release (SDSSDR)-7, ...
  • 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). ...
  • Host galaxies of ultrastrong Mg II absorbers at z ∼ 0.5 
    Guha, Labanya Kumar; Srianand, Raghunathan; Dutta, Rajeshwari; Joshi, Ravi; Noterdaeme, Pasquier; Petitjean, Patrick (Oxford University Press on behalf of Royal Astronomical Society, 2022-07)
    From a sample of 109 candidate ultrastrong Mg II (USMg II; having rest equivalent width of Mg II, W2796 > 3.0 Å) systems at z = 0.4–0.6, we confirm 27 and identify host galaxies of 20 systems based on associated nebular ...
  • 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 ...
  • 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 physically-motivated perspective of Fanaroff–Riley classification of radio galaxies 
    Gopal-Krishna; Wiita, Paul J; Joshi, Ravi; Patra, Dusmanta (Indian Academy of Sciences, 2023-06)
    A small subset of extragalactic double radio sources, termed HYbrid MOrpholgy Radio Sources (HYMORS), is distinguished by a very unusual, hybrid morphology in terms of Fanaroff–Riley (FR) classification. In HYMORS, one ...
  • Spectral index variation across X-shaped radio galaxies 
    Patra, Dusmanta; Joshi, Ravi; Gopal-Krishna (Oxford University Press on behalf of Royal Astronomical Society, 2023-09)
    The formation mechanism of the enigmatic subclass of radio galaxies, called ‘X-shaped radio galaxies’ (XRGs), or ‘winged’ radio galaxies, which account for ∼10 per cent of the radio galaxy population, can be effectively ...
  • The twin radio galaxy TRG J104454+354055 
    Gopal-Krishna; Joshi, Ravi; Patra, Dusmanta; Yang, Xiaolong; Ho, Luis C; Wiita, Paul J; Omar, Amitesh (Oxford University Press on behalf of Royal Astronomical Society, 2022-07)
    We report observations of a bright dumb-bell system of galaxies (z = 0.162) with the upgraded Giant Metrewave Radio Telescope (uGMRT), which show that each member of this gravitationally bound pair of galaxies hosts bipolar ...
  • X-shaped Radio Galaxies: Optical Properties, Large-scale Environment, and Relationship to Radio Structure 
    Joshi, Ravi; Gopal Krishna; Yang, Xiaolong; Shi, Jingjing; Yu, Si-Yue; Wiita; Paul J.; Ho, Luis C.; Wu, Xue-Bing; An, Tao; Wang, Ran; Subramanian, S; Yesuf, Hassen (IOP Publishing, 2019-12)
    In pursuit of clues to the origin of “ winged ” or X-shaped radio galaxies ( XRGs ) we investigate the parent galaxies of a large sample of 106 XRGs for optical – radio axes alignment, interstellar medium, black ...
  • The X-shaped Radio Galaxy J0725+5835 is Associated with an AGN Pair 
    Yang, Xiaolong; Ji, Jialu; Joshi, Ravi; Yang, Jun; An, Tao; Wang, Ran; Ho, Luis C; Roberts, David H; Saripalli, Lakshmi (IOP Publishing, 2022-07-01)
    X-shaped radio galaxies (XRGs) are those that exhibit two pairs of unaligned radio lobes (main radio lobes and wings). One of the promising models for the peculiar morphology is jet reorientation. To clarify this, we ...

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