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Browsing by Subject "Galaxies: jets"

Browsing by Subject "Galaxies: jets"

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  • 2.5-dimensional solution of the advective accretion disk: a self-similar approach 
    Ghosh, S; Mukhopadhyay, B (Institute of Physics, 2009-02)
    We provide a 2.5-dimensional solution to a complete set of viscous hydrodynamical equations describing accretion-induced outflows and plausible jets around black holes/compact objects. We prescribe a self-consistent advective ...
  • The AGN and gas disk in the low surface brightness galaxy PGC045080 
    Das, M; Kantharia, N; Ramya, S; Prabhu, T. P; McGaugh, S. S; Vogel, S. N (Blackwell Publishing, 2007-07)
    We present radio observations and optical spectroscopy of the giant low surface brightness (LSB) galaxy PGC 045080 (or 1300+0144). PGC 045080 is a moderately distant galaxy having a highly inclined optical disc and massive ...
  • AT2020ohl: its nature and probable implications 
    Roy, Rupak; Mandal, Samir; Sahu, D. K; Anupama, G. C; Nandi, Sumana; Kumar, Brijesh (Oxford University Press on behalf of Royal Astronomical Society., 2024-03)
    ASASSN-20hx, a.k.a AT2020ohl, is an ambiguous nuclear transient, which was discovered in the nearby galaxy NGC6297 by the All-Sky Automated Survey for Supernovae. We have investigated the evolution of AT2020ohl using a ...
  • Awakening of the high-redshift blazar CGRaBS J0809+5341 
    Paliya, Vaidehi S; Parker, M. L; Stalin, C. S; Fabian, A. C; Ramya, S; Covino, S; Tagliaferri, G; Sahayanathan, S; Ravikumar, C. D (IOP Publishing, 2015-04)
    CGRaBS J0809+5341, a high-redshift blazar at z = 2.144, underwent a giant optical outburst on 2014 April 19 when it brightened by ~5 mag and reached an unfiltered apparent magnitude of 15.7 mag. This implies an absolute ...
  • Broadband observations of high redshift blazars 
    Paliya, Vaidehi S; Parker, M. L; Fabian, A. C; Stalin, C. S (IOP Publishing, 2016-07-01)
    We present a multi-wavelength study of four high redshift blazars, S5 0014+81 (z = 3.37), CGRaBS J0225+1846 (z = 2.69), BZQ J1430+4205 (z = 4.72), and 3FGL J1656.2−3303 (z = 2.40) using quasi-simultaneous data from the ...
  • A candidate dual AGN in a double-peaked emission-line galaxy with precessing radio jets 
    Rubinur, K; Mousumi Das; Kharb, P; Honey, M (Oxford University Press on behalf of the Royal Astronomical Society, 2017-03)
    We present high-resolution radio continuum observations with the Karl G. Jansky very large array at 6, 8.5, 11.5 and 15 GHz of the double-peaked emission-line galaxy 2MASXJ12032061+1319316. The radio emission has a prominent ...
  • Correlation between optical and γ -ray flux variations in bright flat spectrum radio quasars 
    Rajput, Bhoomika; Stalin, C. S; Sahayanathan, S (Oxford University Press on behalf of the Royal Astronomical Society, 2020-11)
    Blazars are known to show flux variations over a range of energies from low-energy radio to high-energy γ-rays. Cross-correlation analysis of the optical and γ-ray light curves in blazars shows that flux variations are ...
  • 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 ...
  • Correlation between optical flux and polarization variations in flat-spectrum radio quasars on diverse time-scales 
    Pandey, Ashwani; Bhoomika, R; Stalin, C. S (Oxford University Press on behalf of Royal Astronomical Society, 2022-02)
    Study of the polarization behaviour in blazars is a powerful tool to discern the role of the magnetic field in the variable emission process in their relativistic jets. We present here the results of our systematic ...
  • Cosmic evolution of AGN using self-consistent black hole energetics 
    Mangalam, A (Astronomical Society of India, 2015)
    We consider a model that takes into account the mass and spin accreted by the hole and the angular momentum torque due to an electrodynamical jet. The spin evolution is calculated with and without accretion; if the accretion ...
  • A curved 150 pc long jet in the double-peaked emission-line AGN KISSR 434 
    Kharb, P; Vaddi, Sravani; Sebastian, B; Subramanian, S; Mousumi Das; Paragi, Z (IOP Publishing, 2019-02-01)
    Double-peaked emission lines in the narrow- and/or broad-line spectra of active galactic nuclei (AGNs) have been suggested to arise as a result of disky broad/narrow-line regions, jet–medium interaction, or the presence ...
  • The detection of Diffuse Extended Structure in 3C 273: implications for jet power 
    Punsly, B; Kharb, P (IOP Publishing, 2016-12-10)
    We present deep Very Large Array imaging of 3C 273 in order to determine the diffuse, large scale radio structure of this famous radio-loud quasar. Diffuse extended structure (radio lobes) is detected for the first time ...
  • Discovery of Dramatic Optical Variability in SDSS J1100+4421: A Peculiar Radio-loud Narrow-line Seyfert 1 Galaxy? 
    Tanaka, M; Morokuma, T; Itoh, R; Akitaya, H; Tominaga, N; Saito, Y; Stawarz, L; Tanaka, Y, T; Gandhi, P; Ali, G; Aoki, T; Contreras, C; Doi, M; Essam, A; Hamed, G; Hsiao, E. Y; Iwata, I; Kawabata, K. S; Kawai, N; Kikuchi, Y; Kobayashi, N; Kuroda, D; Maehara, H; Matsumoto, E; Mazzali, P. A; Minezaki, T; Mito, H; Miyata, T; Miyazaki, S; Mori, K; Moritani, Y; Morokuma-Matsui, Kana; Morrell, N; Nagao, T; Nakada, Y; Nakata, F; Noma, C; Ohsuga, K; Okada, N; Phillips, M. M; Pian, E; Richmond, M. W; Sahu, D. K; Sako, S; Sarugaku, Y; Shibata, T; Soyano, T; Stritzinger, M. D; Tachibana, Y; Taddia, F; Takaki, K; Takey, Ali; Tarusawa, K; Ui, T; Ukita, N; Urata, Y; Walker, E. S; Yoshii, T (IOP Publishing, 2014-10-01)
    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. ...
  • 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 ...
  • Double-peaked Emission Lines Due to a Radio Outflow in KISSR 1219 
    Kharb, P; Subramanian, S; Vaddi, Sravani; Mousumi Das; Paragi, Z (IOP Publishing, 2017-09)
    We present the results from 1.5 and 5 GHz phase-referenced VLBA and 1.5 GHz Karl G. Jansky Very Large Array (VLA) observations of the Seyfert 2 galaxy KISSR 1219, which exhibits double-peaked emission lines in its optical ...
  • 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). ...
  • The extreme ultraviolet deficit: jet connection in the quasar 1442+101 
    Punsly, B; Marziani, P; Kharb, P; O'Dea, C. P; Vestergaard, M (IOP Publishing, 2015-10-10)
    In previous studies, it has been shown that the long-term time-averaged jet power, Q, is correlated with spectral index in the extreme ultraviolet (EUV), αEUV (defined by n ~ n-a F EUV computed between 700 and 1100 Å ). ...
  • Fermi monitoring of radio-loud narrow-line seyfert 1 galaxies 
    Paliya, Vaidehi S; Stalin, C. S; Ravikumar, C. D (IOP Publishing, 2015-02)
    We present detailed analysis of the γ-ray flux variability and spectral properties of the five radio-loud narrow line Seyfert 1 (RL-NLSy1) galaxies, detected by the Large Area Telescope on board the Fermi Gamma-Ray Space ...
  • The first GeV outburst of the radio-loud narrow-line Seyfert 1 galaxy PKS 1502+036 
    Paliya, Vaidehi S; Stalin, C. S (IOP Publishing, 2016-03)
    The γ-ray-loud narrow-line Seyfert 1 (γ-NLSy1) galaxy PKS 1502+036 (z = 0.409) exhibited its first γ-ray outburst on 2015 December 20. In the energy range of 0.1–300 GeV, the highest flux measured by the Fermi-Large Area ...
  • Flux and spectral variability of Mrk 421 during its moderate activity state using NuSTAR: Possible accretion disc contribution? 
    Mondal, S; Priyanka Rani; Stalin, C. S; Chakrabarti, S. K; Rakshit, S (EDP Sciences, 2022-07)
    Context. The X-ray emission in BL Lac objects is believed to be dominated by synchrotron emission from their relativistic jets. However, when the jet emission is not strong, one could expect signatures of X-ray emission ...

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