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Browsing by Author "Rakshit, S"

Browsing by Author "Rakshit, S"

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  • 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 ...
  • 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 ...
  • 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 ...
  • Dust reverberation mapping of Z229–15 
    Mandal, A. K; Rakshit, S; Stalin, C. S; Wylezalek, D; Patig, M. K; Sagar, R; Mathew, B; Muneer, S; Pal, I (Oxford University Press on behalf of the Royal Astronomical Society, 2021-03)
    We report results of the dust reverberation mapping (DRM) on the Seyfert 1 galaxy Z229–15 at z = 0.0273. Quasi-simultaneous photometric observations for a total of 48 epochs were acquired during the period 2017 July to ...
  • 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 ...
  • Flux and polarization variability of OJ 287 during the early 2016 outburst 
    Rakshit, S; Stalin, C. S; Muneer, S; Neha, S; Paliya, Vaidehi S (IOP Publishing, 2017-02-01)
    The gamma-ray blazar OJ 287 was in a high activity state during 2015 December–2016 February. Coinciding with this high brightness state, we observed this source for photometry on 40 nights in R-band and for polarimetry on ...
  • 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 ...
  • 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 ...
  • High-redshift narrow-line Seyfert 1 galaxies: a candidate sample 
    Rakshit, S; Stalin, C. S; Kotilainen, Jari; Shin, Jaejin (IOP Publishing, 2021-03)
    The study of narrow-line Seyfert 1 galaxies (NLS1s) is now mostly limited to low redshift (z < 0.8) because their definition requires the presence of the Hβ emission line, which is redshifted out of the spectral coverage ...
  • 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 ...
  • Long-term ultraviolet variability of Seyfert galaxies 
    Sukanya, N; Stalin, C. S; Joseph, P; Rakshit, S; Praveen, D; Damle, R (Indian Academy of Sciences, 2018-12)
    Flux variability is one of the defining characteristics of Seyfert galaxies, a class of active galactic nuclei (AGN). Although these variations are observed over a wide range of wavelengths, results on their flux variability ...
  • Long-term ultraviolet variability of Seyfert galaxies 
    Sukanya, N; Stalin, C. S; Joseph, P; Rakshit, S; Praveen, D; Damle, R (Indian Academy of Sciences, 2018-12)
    Flux variability is one of the defining characteristics of Seyfert galaxies, a class of active galactic nuclei (AGN). Although these variations are observed over a wide range of wavelengths, results on their flux variability ...
  • 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 ...
  • Optical variability of narrow-line and broad-line Seyfert 1 galaxies 
    Rakshit, S; Stalin, C. S (IOP Publishing, 2017-05)
    We studied the optical variability ( OV ) of a large sample of narrow-line Seyfert 1 ( NLSy1 ) and broad-line Seyfert 1 ( BLSy1 ) galaxies with z  <  0.8 to investigate any differences in their OV ...
  • PAH features within few hundred parsecs of active galactic nuclei 
    Jensen, J. J; Honig, S. F; Rakshit, S; Alonso-Herrero, A; Asmus, D; Gandhi, P; Kishimoto, M; Smette, A; Tristram, K. R. W (Oxford University Press on behalf of the Royal Astronomical Society, 2017-08)
    Spectral features from polycyclic aromatic hydrocarbon (PAH) molecules observed in the mid-infrared (mid-IR) range are typically used to infer the amount of recent and ongoing star formation on kiloparsec scales around ...
  • Probing the central engine and environment of AGN using ARIES 1.3-m and 3.6-m telescopes 
    Chand, H; Rakshit, S; Jalan, P; Ojha, V; Srianand, R; Vivek, M; Mishra, S; Omar, A; Kumar, P; Joshi, R; Gopal Krishna; Kumar, R (Societe Royale des Sciences de Liege, 2018-04)
    : We discuss three long term observational programmes to probe the central engine and environment of active galactic nuclei (AGN) using the recently installed ARIES 1.3-m and 3.6-m telescopes. The first programme is on ...
  • Properties of Narrow line Seyfert 1 galaxies 
    Rakshit, S; Stalin, C. S; Chand, H; Zhang, X (Bulletin de la Societe Royale des Sciences de Liege, 2018-04)
    Narrow line Seyfert 1 (NLSy1) galaxies constitute a class of active galactic nuclei characterized by the full width at half maximum (FWHM) of the Hα broad emission line <2000 km s-1 and the flux ratio of [O III] to Hα ...
  • Rare Finding of a 100 Kpc Large, Double-lobed Radio Galaxy Hosted in the Narrow-line Seyfert 1 Galaxy SDSS J103024.95+551622.7 
    Rakshit, S; Stalin, C. S; Hota, A; Konar, C (IOP Publishing, 2018-12)
    Among the many varieties of active galactic nuclei (AGNs) known, narrow-line Seyfert 1 (NLSy1) galaxies are a puzzling class, particularly after the discovery of γ-ray emission in a handful of them using observations from ...
  • REMAP: Determination of the inner edge of the dust torus in AGN by measuring time delays 
    Mandal, A. K; Rakshit, S; Pal, I; Stalin, C. S; Sagar, R; Mathew, B. (Societe Royale des Sciences de Liege, 2019-10)
    Active galactic nuclei (AGN) are high luminosity sources powered by accretion of matter onto super-massive black holes (SMBHs) located at the centres of galaxies. According to the Unification model of AGN, the SMBH is ...

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