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Browsing by Subject "Galaxies: Seyfert"

Browsing by Subject "Galaxies: Seyfert"

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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 ...
  • Broadband observations of the gamma-ray emitting narrow line Seyfert 1 galaxy SBS 0846+513 
    Paliya, Vaidehi S; Rajput, Bhoomika; Stalin, C. S; Pandey, S. B (IOP Publishing, 2016-03)
    We present the results of our broadband study of the γ -ray emitting narrow line Seyfert 1 ( NLSy1 ) galaxy SBS 0846 + 513 ( z = 0.585 ) . This includes multiband fl ux variations, γ -ray spectral analysis, ...
  • 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 ...
  • A Catalog of Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey Data Release 12 
    Rakshit, S; Stalin, C. S; Chand, H; Zhang, Xue-Guang (IOP Publishing, 2017-04)
    We present a new catalog of narrow-line Seyfert 1 (NLSy1) galaxies from the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). This was obtained by a systematic analysis through modeling of the continuum and emission ...
  • Coronal Proerties of the Seyfert 1 Galaxy 3C 120 with NuSTAR 
    Priyanka Rani; Stalin, C. S (IOP Publishing, 2018-04-01)
    We present a measurement of the cut-off energy, a proxy for the temperature of the corona in the nuclear continuum of the Seyfert 1 galaxy 3C 120 using ~120 ks of observation from NuSTAR. The quality broadband spectrum ...
  • 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 ...
  • Determination of the size of the dust torus in H0507+164 through optical and infrared monitoring 
    Amit Kumar; Rakshit, S; Kshama, S. K; Stalin, C. S; Mathew, B; Hoenig, Sebastian; Gandhi, Poshak; Sagar, R; Pandge, M. B (Oxford University Press on behalf of the Royal Astronomical Society, 2018-04)
    The time delay between flux variations in different wavelength bands can be used to probe the inner regions of active galactic nuclei (AGNs). Here, we present the first measurements of the time delay between optical and ...
  • 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. ...
  • Discovery of soft and hard X-ray time lags in low-mass AGNs 
    Mallick, L; Wilkins, D. R; Alston, W. N; Markowitz, A; Marco, B. De; Parker, M. L; Lohfink, A. M; Stalin, C. S (Oxford University Press on behalf of the Royal Astronomical Society, 2021-05)
    The scaling relations between the black hole (BH) mass and soft lag properties for both active galactic nuclei (AGNs) and BH X-ray binaries (BHXRBs) suggest the same underlying physical mechanism at work in accreting BH ...
  • Dissecting galaxies: spatial and spectral separation of emission excited by star formation and AGN activity 
    Davies, R. L; Groves, B; Kewley, L; Dopita, M. A; Hampton, E. J; Shastri, P; Scharwachter, J; Sutherland, R; Kharb, P; Bhatt, H. C; Jin, C; Banfield, J; Zaw, I; James, B; Juneau, S; Srivastava, S (Oxford University Press on behalf of the Royal Astronomical Society, 2016-10-21)
    The optical spectra of Seyfert galaxies are often dominated by emission lines excited by both star formation and active galactic nucleus (AGN) activity. Standard calibrations (such as for the star formation rate) are not ...
  • 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 ...
  • Estimation of the size and structure of the broad line region using Bayesian approach 
    Mandal, A. K; Rakshit, S; Stalin, C. S; Petrov, R. G; Mathew, B; Sagar, R (Oxford University Press on behalf of the Royal Astronomical Society, 2021-04)
    Understanding the geometry and kinematics of the broad line region (BLR) of active galactic nuclei (AGN) is important to estimate black hole masses in AGN and study the accretion process. The technique of reverberation ...
  • 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 ...
  • 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 ...
  • Gamma-Ray-emitting Narrow-line Seyfert 1 Galaxies in the Sloan Digital Sky Survey 
    Paliya, Vaidehi S; Ajello, M; Rakshit, S; Amit Kumar; Stalin, C. S; Kaur, A; Hartmann, D (IOP Publishing, 2018-01)
    The detection of signi fi cant γ -ray emission from radio-loud narrow-line Seyfert 1 ( NLSy1s ) galaxies enables us to study jets in environments different than those in blazars. However, due to the small number ...
  • Intra-night optical variability characteristics of different classes of narrow-line seyfert 1 galaxies 
    Kshama, S. K; Paliya, Vaidehi S; Stalin, C. S (Oxford University Press on behalf of the Royal Astronomical Society, 2017-04)
    In a first systematic effort to characterize the intra-night optical variability (INOV) of different classes of narrow-line Seyfert 1 (NLSy1) Galaxies, we have carried out observations on a sample of radio-loud (RL) and ...
  • Kiloparsec-scale radio emission in Seyfert and LINER galaxies 
    Singh, V; Ishwara-Chandra, C. H; Wadadekar, Yogesh; Beelen, Alexandre; Kharb, P (Oxford University Press on behalf of the Royal Astronomical Society, 2015-01-01)
    Seyfert and LINER galaxies are known to exhibit compact radio emission on ∼10–100 pc scales, but larger Kiloparsec-Scale Radio structures (KSRs) often remain undetected in sub-arcsec high-resolution observations. We ...
  • Kinematics and Excitation of the Nuclear Spiral in the Active Galaxy Arp 102B 
    Couto, G. S; Storchi-Bergmann, T; Axon, D. J; Robinson, A; Kharb, P; Riffel, R. A (Oxford University Press on behalf of the Royal Astronomical Society, 2013-11-11)
    We present a two-dimensional analysis of the gaseous excitation and kinematics of the inner 2.5 × 1.7 kpc2 of the low-ionization nuclear emission-line region (LINER)/Seyfert 1 galaxy Arp 102B, from optical spectra obtained ...
  • Low-frequency radio observations of Seyfert galaxies: A test of the unification scheme 
    Singh, V; Shastri, P; Ishwara-Chandra, C. H; Athreya, R (EDP Sciences, 2013-06)
    Aims. We present low-frequency radio imaging and spectral properties of a well-defined sample of Seyfert galaxies using GMRT 240/610 MHz dual frequency observations. Radio spectra of Seyfert galaxies over 240 MHz to 5.0 ...
  • Mass of the black hole in the Seyfert 1.5 galaxy H 0507+164 from reverberation mapping 
    Stalin, C. S; Jeyakumar, S; Coziol, R; Pawase, R. S; Thakur, S. S (Wiley-Blackwell, 2011-09)
    We present the results of our optical monitoring campaign of the X-ray source H 0507+164, a low-luminosity Seyfert 1.5 galaxy at a redshift z= 0.018. Spectroscopic observations were carried out during 22 nights in 2007, ...

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