IIA Institutional Repository: Recent submissions

  • Partial Redistribution Theory and its Applications in the Interpretation of the Second Solar Spectrum 
    Nagendra, K. N (Astronomical Society of the Pacific, 2014-10)
    In this review we first describe briefly the techniques to formulate partial redistribution (PRD) matrices for polarized line scattering on atoms. These matrices have to be formulated by either semi-classical or quantum ...
  • Intrinsically Polarized Blend Lines 
    Sowmya, K; Nagendra, K. N; Sampoorna, M (Astronomical Society of the Pacific, 2014-10)
    The Second Solar Spectrum formed by coherent scattering processes in the Sun, is highly structured. It is characterized by numerous blend lines, both intrinsically polarizing and depolarizing, superposed on the background ...
  • A Co-Phasing technique for segmented mirror telescopes 
    Jacob, A (Indian Institute of Astrophysics, 2014-08)
    We are in an era where astronomy had taken steps to build giant telescope which have optics of size more than 10m, we can commonly call them ELTs or Extremely Large Telescopes. Due to various reasons like cost, ease of ...
  • The Role of Quantum Interference and Partial Redistribution in the Solar Ba II D2 4554 Ã… Line 
    Smitha, H. N; Nagendra, K. N; Stenflo, J. O; Sampoorna, M (Astronomical Society of the Pacific, 2014-10)
    The Ba ii D2 line at 4554 Å is a good example, where the F-state interference effects due to the odd isotopes produce polarization profiles, which are very different from those of the even isotopes that do not exhibit ...
  • Electron Scattering Redistribution Effect on Atomic Line Polarization 
    Supriya, H. D; Nagendra, K. N; Ravindra, B; Sampoorna, M (Astronomical Society of the Pacific, 2014-10)
    The scattering of line photons on free electrons modifies the polarization of the atomic spectral lines. Hence it is important to treat scattering by electrons as a redistribution process and to study in detail its effect ...
  • Studies on Carbon-Enhanced Metal-Poor (CEMP) stars 
    Drisya, K (Indian Institute of Astrophysics, 2015-03)
    Chemical composition of metal-poor stars are crucial to develop an understanding of the nature of the earliest stars formed in the universe, the nucleosynthesis events associated with them, as well as, to redefine the ...
  • Scattering polarization with Paschen-Back effect as a tool to diagnose the magnetic structuring of the solar atmosphere 
    Sowmya, K (Indian Institute of Astrophysics, 2016-03)
    The Sun is a unique physical laboratory in which the various domains of physics inaccessible to laboratories on earth can be studied in great detail. Its proximity allows us to understand it in great depths. George Ellery ...
  • Exploration of the second solar spectrum through polarimetric studies 
    Supriya, H. D (Indian Institute of Astrophysics, 2016-03)
    The discovery of Zeeman effect opened a new window to observe the Sun. It enabled to understand the magnetic field which is one of the basic features that govern different physical processes on the Sun. These magnetic ...
  • Magnetoconvective flows and waves in the lower solar atmosphere 
    Sangeetha, C. R (Indian Institute of Astrophysics, 2017-01)
    Sun has complex magnetic features like sunspots, magnetic bright points, plages, network fields, filaments, etc. These complex magnetic features are found to be associated with various observed dynamical phenomenons like ...
  • On the coupling between lower and upper atmosphere of the Sun 
    Samanta, T (Indian Institute of Astrophysics, 2017-01)
    The thesis is focused on the study of the small-scale transients and waves as seen in the different layers of the solar atmosphere and the coupling between the different layers. The unique high resolution data obtained ...
  • Development of detectors for space missions and balloon flights 
    Ambily, S (Indian Institute of Astrophysics, 2018-11)
    We are developing compact astronomical payloads for ultraviolet (UV) observations from CubeSats and high altitude balloons. It is important to have a highly sensitive, low noise detector in the UV region where the ...
  • Abundance patterns of old open clusters as tracers of galactic chemical evolution 
    Reddy, A. B. S (Indian Institute of Astrophysics, 2014-06)
    We have initiated a program to explore the presence of chemical inhomogeneities in the Galactic disk using the open clusters (OCs) as ideal probes. We have obtained high S/N - ratio and high- dispersion echelle spectra ...
  • Study of stellar streams in the galaxy 
    Ramya, P (Indian Institute of Astrophysics, 2014-02)
    Our Galaxy, also called the Milky Way, is a spiral galaxy consisting of three major distinct components: bulge, disc and halo. They differ from each other in their structural as well as kinematical and chemical properties. ...
  • Study of sun-like G stars and their exoplanets 
    Gurumath, S. R (Vellore Institute of Technology and Indian Institute of Astrophysics, 2019-05)
    By employing exoplanetary physical and orbital characteristics, aim of this study is to understand the genesis, dynamics, chemical abundance and magnetic field structure of Sun-like G stars and relationship with their ...
  • Application of polarized line formation theory to the solar spectrum 
    Smitha, H. N (Indian Institute of Astrophysics, 2014-06)
    One of the primary causes for the occurrence of observed features on the Sun is its magnetic field. The traditional way of measuring the solar magnetic fields is through the Zeeman effect. Over the decades, as the precision ...
  • Study of lunar surface chemistry using swept charge devices 
    Athiray, P. S (Indian Institute of Astrophysics, 2015-05)
    The study of origin and evolution of the Moon have generated scientific curiosity for a long time. With the improved technology, with larger telescopes and better scientific instruments the lunar surface got revealed and ...
  • Precision controller for segmented mirror telescope actuator: control and tuning 
    Prasanna Deshmukh; Parihar, P. S (IEEE, 2016-03)
    The segmented mirror telescopes are built using small hexagonal mirrors positioned and aligned by the three actuators and six edge sensors per segment to maintain the shape of the primary mirror. The global loop controller ...
  • The Effect of Bulge Mass on Bar Pattern Speed in Disk Galaxies 
    Kataria, Sandeep Kumar; Mousumi Das (IOP Publishing, 2019-11)
    We present a study of the effect of bulge mass on the evolution of bar pattern speed in isolated disk galaxies using N -body simulations. Earlier studies have shown that disk stars at the inner resonances can transfer a ...
  • Concerning the Li-rich status of KIC 9821622: a Kepler field RGB star reported as a Li-rich giant 
    Raghubar Singh; Bharat Kumar, Y; Reddy, B. E; Aoki, W (Oxford University Press on behalf of the Royal Astronomical Society, 2020-01)
    Given the implications for the origin of Li enhancement in red giants, we have reviewed the Li-rich classification of KIC 9821622, the only bonafide red giant branch (RGB) giant with a He inert core to date, reported as a ...
  • Delving into the Historical Ca II K Archive from the Kodaikanal Observatory: The Potential of the Most Recent Digitized Series 
    Chatzistergos, Theodosios; Ermolli, Ilaria; Solanki, Sami K; Krivova, Natalie A; Banerjee, D; Jha, Bibhuti K; Chatterjee, Subhamoy (Springer, 2019-10)
    Full-disc Ca II K photographic observations of the Sun carry direct information as regards the evolution of solar-plage regions for more than a century and are therefore a unique dataset for solar-activity studies. For a ...

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