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Browsing IIAP Publications by Subject "Black hole physics"

Browsing IIAP Publications by Subject "Black hole physics"

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  • Parsec-scale jet properties of the quasar PG 1302-102 
    Mohan, P; An, T; Frey, S; Mangalam, A; Gabanyi, K. E; Kun, E (Oxford University Press on behalf of the Royal Astronomical Society, 2016-12-01)
    The quasar PG 1302−102 is believed to harbour a supermassive binary black hole (SMBBH) system. Using the available 15 GHz and 2–8 GHz, multi-epoch Very Long Baseline Array data, we constrain the pc-scale jet properties ...
  • Polarization and QPOs from jets in black hole systems 
    Mangalam, A (Indian Academy of Sciences, 2018-12)
    The historical observations of polarized jet emission for Blazars are reviewed and previous models are discussed. Motivated by this, a model for polarization of both steady and transient behavior using a helical magnetic ...
  • Probing the Active Massive Black Hole Candidate in the Center of NGC 404 with VLBI 
    Paragi, Z; Frey, S; Kaaret, P; Cseh, D; Overzier, R; Preethi, K (IOP Publishing, 2014-08-10)
    Recently, Nyland et al. argued that the radio emission observed in the center of the dwarf galaxy NGC 404 originates in a low-luminosity active galactic nucleus powered by a massive black hole (MBH, M lsim 106 M ☉). ...
  • Probing the physics of narrow-line regions in active galaxies. III. accretion and cocoon shocks in the liner NGC 1052 
    Dopita, M. A; Ho, I-Ting; Dressel, L. L; Sutherland, R; Kewley, L; Davies, R; Hampton, E; Shastri, P; Kharb, P; Jose, Jessy; Bhatt, H. C; Ramya, S; Scharwachter, J; Jin, C; Banfield, J; Zaw, I; James, B; Juneau, S; Srivastava, S (IOP Publishing, 2015-03-01)
    We present Wide Field Spectrograph integral field spectroscopy and Hubble Space Telescope Faint Object Spectrograph spectroscopy for the low-ionization nuclear emission line region (LINER) galaxy NGC 1052. We infer the ...
  • Probing the physics of narrow-line regions of Seyfert galaxies, I. The case of NGC 5427 
    Dopita, M. A; Scharwachter, J; Shastri, P; Kewley, L. J; Davies, R; Sutherland, R; Kharb, P; Jose, J; Hampton, E; Jin, C; Banfield, J; Basurah, H; Fischer, S (EDP Sciences, 2014-06)
    Context. The spectra of the extended narrow-line regions (ENLRs) of Seyfert 2 galaxies probe the physics of the central active galaxy nucleus (AGN), since they encode the energy distribution of the ionising photons, the ...
  • Relation between Quiescence and Outbursting Properties of GX 339-4 
    Bhowmic, Riya; Debnath, Dipak; Chatterjee, Kaushik; Nagarkoti, Shreeram; Chakrabarti, S. K; Sarkar, Ritabrata; Chatterjee, Debjit; Jana, Arghajit (IOP Publishing, 2021-04-01)
    Galactic black hole candidate GX 339-4 underwent several outbursting phases in the past two and a half decades at irregular intervals of 2–3 years. The nature of these outbursts in terms of the duration, number of peaks, ...
  • Spectral and temporal studies of Swift J1658.2–4242 using AstroSat observations with the JeTCAF model 
    Mondal, Santanu; Jithesh, V (Oxford University Press on behalf of Royal Astronomical Society, 2023-06)
    We present the X-ray spectral and temporal analysis of the black hole X-ray transient Swift J1658.2–4242 observed by AstroSat. Three epochs of data have been analysed using the JeTCAF model to estimate the mass accretion ...
  • Spectral signature of mass outflow in the two component advective flow paradigm 
    Mondal, Santanu; Chakrabarti, S. K (IOP Publishing, 2021-10-10)
    Outflows are common in many astrophysical systems. In the Two Component Advective Flow (TCAF) paradigm, which is essentially a generalized Bondi flow including rotation, viscosity, and cooling effects, the outflow originates ...
  • Stellar and gas dynamical model for tidal disruption events in a quiescent galaxy 
    Mageshwaran, T; Mangalam, A (IOP Publishing, 2015-12-01)
    A detailed model of the tidal disruption events (TDEs) has been constructed using stellar dynamical and gas dynamical inputs that include black hole (BH) mass M•, specific orbital energy E and angular momentum J, star mass ...
  • Study of accretion flows around an ultraluminous X-ray source M82 X-1 using NuSTAR data 
    Mondal, Santanu; Palit, Biswaraj; Chakrabarti, Sandip K (Indian Academy of Sciences, 2022-12)
    We study the spectral properties and accretion flow behavior of an ultraluminous X-ray source M82 X-1 using NuSTAR observations. We use the physical two-component advective flow (TCAF) model to fit the data and to derive ...
  • TeV blazar variability: the firehose instability? 
    Subramanian, P; Shukla, A; Becker, P. A (Wiley-Blackwell, 2012-06)
    Recently observed minute-time-scale variability of blazar emission at TeV energies has imposed severe constraints on jet models and TeV emission mechanisms. We focus on a robust jet instability to explain this variability. ...
  • Variable mass accretion and failed wind explain changing-look phenomena in NGC 1365 
    Mondal, Santanu; Adhikari, T. P; Hryniewicz, K; Stalin, C. S; Pandey, Ashwani (EDP Sciences, 2022-06)
    Changing-look active galactic nuclei (CLAGNs) show a complex nature in their X-ray spectral shape and line-of-sight column-density variation. The physical mechanisms responsible for these variations are unclear. Here, we ...
  • Wide-band view of high-frequency quasi-periodic oscillations of GRS 1915+105 in ‘softer’ variability classes observed with AstroSat 
    Majumder, Seshadri; Sreehari, H; Aftab, Nafisa; Katoch, Tilak; Das, Santabrata; Nandi, Anuj (Oxford University Press on behalf of Royal Astronomical Society, 2022-05)
    We present a comprehensive temporal and spectral analysis of the ‘softer’ variability classes (i.e. θ, β, δ, ρ, κ, ω and γ ) of the source GRS 1915+105 observed by AstroSat during the 2016−2021 campaign. Wide-band (3−60 ...
  • X-ray variability and the inner region in active galactic nuclei 
    Mohan, Prashanth; Mangalam, A (IOP Publishing, 2014-08-20)
    We present theoretical models of X-ray variability attributable to orbital signatures from an accretion disk including emission region size, quasi-periodic oscillations (QPOs), and its quality factor Q, and the emergence ...

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