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Browsing by Subject "Variability"

Browsing by Subject "Variability"

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  • Comments on the variability and physical parameters of the F supergiant Phi Cassiopeiae 
    Ferro, A. A; Parrao, L; Giridhar, S (Astronomical Society of the Pacific, 1988-08)
    UBVRI and uvby photometry and radial velocities have been obtained for the F0 Ia supergiant Phi Cas. The variability is confirmed from the radial velocities; the velocity range is small (Delta V/subr of about 6 km/s). No ...
  • Curvit: An open-source Python package to generate light curves from UVIT data 
    Joseph, P; Stalin, C. S; Tandon, S. N; Ghosh, S. K (Indian Academy of Sciences, 2021-10)
    Curvit is an open-source Python package that facilitates the creation of light curves from the data collected by the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat, India’s first multi-wavelength astronomical ...
  • H-alpha variability in the quiescent spectrum of the recurrent nova T Coronae Borealis 
    Anupama, G. C; Prabhu, T. P (Blackwell Publishing, 1991-12)
    The emission lines in the quiescent spectrum of the recurrent nova T Coronae Borealis are variable. Optical spectra recorded during the years 1985-90 show one full cycle of high and low states. After removing the slow ...
  • 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 ...
  • Multi-band optical variability studies of Blazars 
    Aditi Agarwal (Societe Royale des Sciences de Liege, 2018-04)
    To search for optical variability on a wide range of timescales, we have carried out photometric monitoring of a dozen blazars. CCD magnitudes in B, V, R and I pass-bands were determined for > 10,000 new optical observations ...
  • Multiwavelength study of the variability in blazars 
    Baliyan, K. S (Astronomical Society of India, 2001)
    Blazars are the radio-loud AGNs with polarized, highly luminous and rapidly variable non-thermal continuum emission ranging from radio to ??rays, from a relativistic jet. These features are interpreted in terms of the ...
  • 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 ...
  • Rapid H-alpha variability in Phi Persei 
    Ghosh, K. K; Sanjeevkumar, T; Jaykumar, K; Kuppuswamy, K; Rosario, M. J (Astronomical Society of the Pacific, 1988-06)
    A search for rapid variability of H-alpha with a time resolution from 30 to 45 seconds is performed for Phi Per. In total, 42 spectra in H-alpha were obtained during three nights. Results show the presence of rapid irregular ...
  • Rapid polarization variability in intense sources 
    Gangadhara, R. T; Krishan, V (The American Astronomical Society, 1995-02)
    We have recently reported the polarization changes of the intense electromagnetic radiation, in active galactic nuclei and pulsars, due to stimulated Raman scattering. In this paper, we show that the incident and the ...
  • A search for intra-night optical variability in radio-quiet QSOs 
    Gopal-Krishna; Sagar, R; Witta, P. J (Royal Astronomical Society, 1993-06-15)
    We report results from a new program, using the 2.34-m Vainu Bappu Telescope, to search for intra-night optical variability in five QSOs which are radio-quiet but optically bright and luminous. Our limited data show mild ...
  • Search for rapid H-alpha variability studies in Be stars - 28 Eri, X Ophiuchi, 66 Ophiuchi and Pi Aquarii 
    Ghosh, K. K (EDP Sciences, 1988-10)
    In order to search for rapid Hα variability in Be stars, a series of Hα profiles were observed on a time scale of few minutes for 28 Eri, X Oph, 66 Oph and π Aqr. In total, 95 and 54 Hα profiles were obtained for the program ...
  • Study of variability in BL Lac objects 
    Baliyan, K. S; Ganesh, S; Joshi, U. C; Shah, C. R; Vadher, N. M; Deshpande, M. R (Astronomical Society of India, 2001)
    We have monitored some of the BL Lac objects, such as OJ287, Mrk 421, Mrk 501 etc from Mt Abu Infrared Observatory, using optical photopolarimeter, CCD and NICMOS-3 IR array mounted at the Cassegrain focus of the 1.2 m ...

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