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Browsing IIAP Publications by Title

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  • Measurement of Kodaikanal white-light images - IV. Axial Tilt Angles of Sunspot Groups 
    Sivaraman, K. R; Gupta, S. S; Howard, R. F (Kluwer Academic Publishers, 1999-10)
    The Kodaikanal sunspot data set, covering the interval 1906-1987, is used in conjunction with the similar Mount Wilson sunspot data set, covering the interval 1917-1985, to examine characteristics of sunspot group axial ...
  • Measurement of Kodaikanal white-light images - VI. Variation of Rotation Rate with Age of Sunspot Groups 
    Sivaraman, K. R; Sivaraman, H; Gupta, S. S; Howard, R. F (Springer, 2003-05)
    We find from an analysis of the Kodaikanal sunspot group data that the rotation rates of spot groups increase with their age when the rotation rates are computed after sorting the spot groups life-span-wise. We confirm ...
  • Measurement of kodaikanal white-light images – V. Tilt-angle and size variations of sunspot groups 
    Howard, R. F; Sivaraman, K. R; Gupta, S. S (Springer, 2000-10)
    We examine here the variations of tilt angle and polarity separation (as defined in this paper) of multi-spot sunspot groups from the Kodaikanal and Mount Wilson data sets covering many decades. We confirm the tilt-angle ...
  • Measurement of Kodaikanal white-light images. I - A comparison of 35 years of Kodaikanal and Mount Wilson sunspot data 
    Sivaraman, K. R; Gupta, S. S; Howard, R. F (Kluwer Academic Publishers, 1993-07)
    Areas and positions of individual sunspot umbrae measured in white-light solar images from Kodaikanal and Mount Wilson are compared and shown to be in quite good agreement. The agreement is sufficiently good that it is ...
  • Measurement of Kodaikanal White-Light Images: Relaxation of Tilts of Spot Groups as Indicator of Subsurface Dynamics of Parent Flux Loops 
    Sivaraman, K. R; Gokhale, M. H; Sivaraman, H; Gupta, S. S; Howard, R. F (The American Astronomical Society, 2007-03)
    We reexamine the evolution of the observed tilts θ of spot groups with life spans 2–7 days in the two latitude belts <13° and >13°. Using an iterative procedure, we refine the linear fit between θ and the daily tilt angle ...
  • Measurement of Solar Magnetic Fields 
    Bhattacharyya, J. C; Balasubramaniam, K. S (Indian Institute of Astrophysics, Bangalore, 1986)
    The paper reviews several methods of estimation of solar magnetic fields so far employed. The possibility of measurement of the vector magnetic fields by using two dimensional detector arrays is discussed. A program for ...
  • Measurement of vector magnetic fields. I - Theoretical approach to the instrumental polarisation of the Kodaikanal Solar Tower 
    Balasubramaniam, K. S; Venkatakrishnan, P; Bhattacharyya, J. C (D. Reidel Publishing Co., 1985-09)
    The observations of Stokes line profiles require an accurate knowledge of the instrumental polarisation caused by optical components in the path of the light beam. In this context we present a theoretical approach to the ...
  • Measurement of Water Vapour over Delhi during the Solar Eclipse - 1995 
    Bose, S; Lal, M; Ghosh, A. B (Indian Institute of Astrophysics, Bangalore, 1997)
    Ground-based IR spectroradiometer has been used for the measurements of water vapour over Delhi (28.7N, 77.2E, 220MSL) during October 24, 1995 solar eclipse. Water vapour variation has been measured during solar eclipse ...
  • Measurements of 220 GHz atmospheric transparency at IAO, Hanle, during 2000-2003 
    Ananthasubramanian, P. G; Yamamoto, S; Prabhu, T. P; Angchuk, D (Astronomical Society of India, 2004-06)
    A 220 GHz tipping radiometer was installed at the Indian Astronomical Observatory (IAO), Hanle (Latitude 32o46'46" N; Longitude 78o57'51" E; Altitude 4500 m, above msl) towards the end of December 1999. The system is in ...
  • Measurements of atmospheric turbulence parameters at Vainu Bappu Observatory using short-exposure CCD images 
    Sreekanth Reddy, V; Banyal, R. K; Sridharan, R; Aishwarya, S (IOP Publishing, 2019-05)
    We report atmospheric turbulence parameters, namely atmospheric seeing, tilt-anisoplanatic angle (θ0) and coherence time (τ0), measured under various sky conditions, at Vainu Bappu Observatory in Kavalur. Bursts of short ...
  • Measurements of linear polarization of some Herbig Ae/Be stars 
    Jain, S. K; Bhatt, H. C; Sagar, R (The American Physical Society, 1990-05)
    The linear polarization of eight bright Herbig Ae/Be stars in UBVRI bands has been measured. No unique wavelength dependence of polarization magnitude or direction is found in these measurements. Comparison with earlier ...
  • Measurements of photoinduced refractive index changes in bacteriorhodopsin films 
    Banyal, R. K; Prasad, B. R (Indian Academy of Sciences, 2007-03)
    We report the pump--probe measurements of nonlinear refractive index changes in photochromic bacteriorhodopsin films. The photoinduced absorption is caused by pump beam at 532 nm and the accompanying refractive ...
  • Measurements of solar differential rotation using the century long kodaikanal sunspot data 
    Jha, Bibhuti K; Priyadarshi, Aditya; Mandal, Sudip; Chatterjee, Subhamoy; Banerjee, D (Springer, 2021-01)
    The rotational profile of the Sun is considered to be one of the key inputs in a solar dynamo model. Hence, precise and long-term measurements of this quantity is important for our understanding of solar magnetism and its ...
  • Measuring the level of nuclear activity in Seyfert galaxies and the unification scheme 
    Singh, V; Shastri, P; Risaliti, G (EDP Sciences, 2011-09)
    Context. The unification scheme of Seyfert galaxies hypothesizes that Seyfert type 1s and type 2s are intrinsically similar and the observed differences between the two subtypes are solely due to the differing orientations ...
  • A mechanism for injection of ultrahigh energy extragalactic cosmic rays 
    de Sabbata, V; Sivaram, C (International Cosmic Ray, 1990)
  • The MeerKAT Galaxy Cluster Legacy Survey. I. Survey Overview and Highlights 
    Knowles, K; Cotton, W. D; Rudnick, L; Camilo, F; Goedhart, S; Deane, R; Ramatsoku, M; Bietenholz, M. F; Bruggen, M; Button, C; Chen, H; Ranchod, S; Retana-Montenegro, E; Sebokolodi, L; Sikhosana, S. P; Smirnov, O; Cheetham, T; Thorat, K; Venturi, T; Abbott, T. D; Adam, R. M; Kotze, A. G; Adams, G; Aldera, M. A; Bauermeister, E. F; Bennett, T. G. H; Bode, W. A; Botha, D. H; de Villiers, D. I. L; Botha, A. G; Dikgale-Mahlakoana, M. A; du Toit, L. J; Kriek, N; Esterhuyse, S. W. P; Fadana, G; Fanaroff, B. L; Manley, J. R; Fataar, S; Foley, A. R; Fourie, D. J; Frank, B. S; Gamatham, R. R. G; Gatsi, T. G; Kriel, H; Geyer, M; Gouws, M; Gumede, S. C; Heywood, I; Marais, S. J; Hlakola, M. J; Hokwana, A; Hoosen, S. W; Horn, D. M; Horrell, J. M. G; Krishnan, V. K; Hugo, B. V; Isaacson, A. R; Jonas, J. L; Jordaan, J. D. B; Joubert, A. F; Maree, M. D. J; Julie, R. P. M; Kapp, F. B; Kasper, V. A; Kenyon, J. S; Kusel, T. W; Kotze, P. P. A; Martens, A; Legodi, L. S; Lehmensiek, R; Liebenberg, D; Lord, R. T; Taljaard, B; Lunsky, B. M; Madisa, K; Magnus, L. G; Main, J. P. L; Makhaba, A; Makhathini, S; Mauch, T; Malan, J. A; McAlpine, K; Merry, B. C; Tasse, C; Millenaar, R. P; Mokone, O. J; Monama, T. E; Chibueze, J. O; Mphego, M. C; New, W. S; Ngcebetsha, B; Ngoasheng, K. J; Ockards, M. T; Otto, A. J; Tiplady, A. J; Patel, A. A; Peens-Hough, A; Perkins, S. J; Ramanujam, N. M; Clarke, T. E; Ramudzuli, Z. R; Ratcliffe, S. M; Renil, R; Robyntjies, A; Rust, A. N; Toruvanda, O; Salie, S; Sambu, N; Schollar, C. T. G; Schwardt, L. C; Schwartz, R. L; Gasperin, F. de; Serylak, M; Siebrits, R; Sirothia, S. K; Slabber, M; Twum, S. N; Sofeya, L; Ianjamasimanana, R; van Balla, T. J; van der Byl, A; van der Merw, C; van Dy, C. L; Brederode, L. R. S; Van Tonder, V; Van Wyk, R; Venter, A. J; Venter, M; Welz, M. G; William, L. P; Jozsa, G. I. G; Xaia, B; Hilton, M; Kesebonye, K. C; Buchner, S; Kolokythas, K; Kraan-Korteweg, R. C; Lawrie, G; Lochner, M; Loubser, S. I; Marchegiani, P; Mhlahlo, N; Moodley, K; Murphy, E; Namumba, B; Burger, J. P; Oozeer, N; Parekh, V; Pillay, D. S; Passmoo, S. S; Ramaila, A. J. T (EDP Sciences, 2022-01)
    MeerKAT’s large number (64) of 13.5 m diameter antennas, spanning 8 km with a densely packed 1 km core, create a powerful instrument for wide-area surveys, with high sensitivity over a wide range of angular scales. The ...
  • Membership of stars in faint galactic open clusters 
    Babu, G. S. D (Indian Academy of Sciences, 1983-12)
    Low-dispersion spectra of the order of 1000 Å mm-1 have been obtained for stars in several faint galactic clusters with a transmission grating placed in front of the photographic plate at the Cassegrain focus of the Kavalur ...
  • Membrane-based deformable mirror: intrinsic aberrations and alignment issues 
    Bayanna, A. R; Louis, R. E; Chatterjee, S; Mathew, S. K; Venkatakrishnan, P (Optical Society of America, 2015-03-01)
    A deformable mirror (DM) is an important component of an adaptive optics system. It is known that an on-axis spherical/parabolic optical component, placed at an angle to the incident beam introduces defocus as well as ...
  • Memoirs of the Kodaikanal Observatory, Volume II: An Atlas of Equatorial Ionograms 
    Bhargava, B. N; Saha, A. K (Kodaikanal Observatory, Kodaikanal, 1967)
  • Mercury monohalides: suitability for electron electric dipole moment searches 
    Srinivasa Prasannaa, V; Vutha, A. C; Abe, M; Das, B. P (The American Physical Society, 2015-05)
    Heavy polar diatomic molecules are the primary tools for searching for the T-violating permanent electric dipole moment of the electron (eEDM). Valence electrons in some molecules experience extremely large effective ...

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