IIA Institutional Repository: Recent submissions

  • Polarized Line Formation in Arbitrary Strength Magnetic Fields: The Case of a Two-level Atom with Hyperfine Structure Splitting 
    Sampoorna, M; Nagendra, K. N; Sowmya, K; Stenflo, J. O; Anusha, L. S (IOP Publishing, 2019-10-01)
    Quantum interference effects, together with partial frequency redistribution (PFR) in line scattering, produce subtle signatures in the so-called Second Solar Spectrum (the linearly polarized spectrum of the Sun). These ...
  • Finding the Critical Decay Index in Solar Prominence Eruptions 
    Vasantharaju, N.; Vemareddy, P; Ravindra, B; Doddamani, V. H (IOP Publishing, 2019-11)
    The background fi eld is assumed to play a prime role in erupting structures like prominences. In the fl ux rope models, the critical decay index ( n c ) is a measure of the rate at which background fi eld ...
  • In fl uence of Wolf – Rayet Stars on Surrounding Star-forming Molecular Clouds 
    Baug, T; Richard de Grijs; Dewangan, L. K; Herczeg, Gregory J; Ojha, D. K; Ke Wang; Licai Deng; Bhatt, B. C (IOP Publishing, 2019-11)
    We investigate the in fl uence of Wolf – Rayet ( W-R ) stars on their surrounding star-forming molecular clouds. We study fi ve regions containing W-R stars in the inner Galactic plane ( l ∼ [ 14 ° ...
  • Ultraviolet Imaging Telescope View of Dwarf Irregular Galaxy IC 2574: Is the Star Formation Triggered Due to Expanding H I Shells? 
    Chayan Mondal; Subramaniam, A; Koshy George (IOP Publishing, 2019-11)
    Star-forming dwarf galaxies in the local volume are diverse and ideal test beds to understand the details of star formation in a variety of environments. Here we present a deep far-UV ( FUV ) imaging study of the ...
  • Spectroscopic study of the Carbon-Enhanced Metal-Poor star: HE 0110-0406 
    Meenakshi, P; Goswami, A; Doddamani, V. H (Societe Royale des Sciences de Liege, 2019-10)
    The halo system of the Milky way comprises the vast majority of the presently observed metal-poor ([Fe/H] <1.0) and very metal-poor ([Fe/H] <2.0) stars. A sizable fraction (~ 30%) of the metal-poor stars with carbon ...
  • Detecting Outliers in SDSS using Convolutional Neural Network 
    Sharma, K; Kembhavi, Ajit; Kembhavi, Aniruddha; Sivarani, T; Abraham, S. (Societe Royale des Sciences de Liege, 2019-10)
    We propose an automated algorithm based on Convolutional Neural Network (CNN) for the detection of peculiar objects in large databases using their spectral observations. A convolutional neural network is a class of ...
  • Planckian pre big bang phase of the Universe 
    Sivaram, C; Arun, K; Rebecca, L (Springer, 2020-01)
    The standard model of cosmology, although very successful, has problems with the very initial phase, such as the existence of a singularity when the density and curvature becomes infinite. In this work we propose a possible ...
  • Diffraction by ruled gratings with variable spacing: fundamental method of intensity calculation 
    Chatterjee, S; Vani, V. C; Haghighi, Rezvan R; Banyal, R. K (Optical Society of America, 2019-11-01)
    A regular diffraction grating produces intensity patterns that combine waves coming through equispaced slits, so that the waves emerging from any two neighboring slits have identical phase differences. In this paper, we ...
  • High-resolution spectroscopy of the high-velocity hot post-AGB star IRAS 18379–1707 (LS 5112) 
    Ikonnikova, N. P; Parthasarathy, M; Dodin, A. V; Hubrig, S; Sarkar, G (Oxford University Press on behalf of the Royal Astronomical Society, 2020-02)
    The high-resolution (⁠R∼48000⁠) optical spectrum of the B-type supergiant LS 5112, identified as the optical counterpart of the post-AGB candidate IRAS 18379–1707 is analysed. We report the detailed identifications of the ...
  • Application of convolutional neural networks for stellar spectral classification 
    Sharma, K; Kembhavi, Ajit; Kembhavi, Aniruddha; Sivarani, T; Abraham, Sheelu; Vaghmare, Kaustubh (Oxford University Press on behalf of the Royal Astronomical Society, 2020-01)
    Due to the ever-expanding volume of observed spectroscopic data from surveys such as SDSS and LAMOST, it has become important to apply artificial intelligence (AI) techniques for analysing stellar spectra to solve spectral ...
  • Sunspot drawings at Kodaikanal Observatory: a representative results on hemispheric sunspot numbers and area measurements 
    Ravindra, B; Kumaravel, P; Selvendran, R; Samuel, Joyce; Kumar, P; Nancy Jassoria; Navneeth, R. S (Springer, 2020-01)
    The importance of the periodicity in sunspot appearance was well recognized by the mid-19th century. Several observatories around the globe have made the record of sunspots in the form of drawings and preserved them safely ...
  • The VMC survey – XXXIV. Morphology of stellar populations in the Magellanic Clouds 
    Youssouf, Dalal El; Cioni, Maria-Rosa L; Bell, Cameron P. M; Rubele, Stefano; Bekki, Kenji; Grijs, Richard de; Girardi, Leo; Ivanov, Valentin D; Matijevic, Gal; Niederhofer, Florian; Oliveira, Joana M; Ripepi, Vincenzo; Subramanian, S; van Loon, Jacco Th (Oxford University Press on behalf of the Royal Astronomical Society, 2019-11)
    The Magellanic Clouds are nearby dwarf irregular galaxies whose morphologies show different properties when traced by different stellar populations, making them an important laboratory for studying galaxy morphologies. We ...
  • Testing Alfvén wave propagation in a “realistic” set-up of the solar atmosphere 
    Chatterjee, Piyali (Taylor & Francis, 2020-07)
    We present a radiative magneto-hydrodynamic simulation set-up using the pencil code to study the generation, propagation and dis- sipation of Alfvén waves in the solar atmosphere which includes a convective layer, ...
  • Evolution of the universe and Earth’s place in cosmos – The 2019 Nobel Prize for Physics 
    Murthy, J (Indian Academy of Sciences, 2019-11-10)
    This was an unusual Nobel prize in that it was awarded ‘for contributions to our understanding of the evolution of the universe and Earth’s place in the cosmos’. This is a broad area which could include almost anything in ...
  • Stellar and Galactic studies with the 2-m Himalayan Chandra Telescope 
    Goswami, A (Societe Royale des Sciences de Liege, 2019-10)
    The Himalayan Chandra Telescope (HCT), of the Indian Astronomical Observatory (IAO), is currently one of the most heavily subscribed telescopes in India. The telescope has been in regular use for scientific observations ...
  • Probing the Galactic s-process nucleosynthesis using barium stars 
    Goswami, A.; Jameela, S (Societe Royale des Sciences de Liege, 2019-10)
    The origin and evolution of neutron-capture elements in our Galaxy is poorly understood. In this work, we have attempted to understand the Galactic s-process nucleosynthesis using barium stars as probes. We have performed ...
  • Optical characterization and Radial velocity monitoring of Exoplanet and Eclipsing Binary candidates 
    Joshi, Y. C; De Cat, P; Panchal, A; Goswami, A; Lampens, P; Vermeylen, L; Maurya, J (Societe Royale des Sciences de Liege, 2019-10)
    In recent times, many new exoplanet and eclipsing binary candidates are reported, particularly from the archival data produced by the Kepler space mission destined to detect exoplanets in the Cygnus-Lyra region of the sky. ...
  • Magnetic activities on active solar-type stars 
    Naik, S; Pandey, J. C; Naik, S; Savanov, I. S; Raj, A. (Societe Royale des Sciences de Liege, 2019-10)
    We present results obtained from the studies of magnetic activities on four solar-type stars (F-type star KIC 6791060, K-type star LO Peg, and two M-type planet-hosting stars K2–33 and EPIC 211901114) by using optical ...
  • 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 ...
  • Scientific potential of the Indo-Belgian 3.6-m DOT in the field of Galactic Astronomy 
    Sagar, R; Kumar, B; Subramaniam, A (Societe Royale des Sciences de Liege, 2019-10)
    India and Belgium have jointly established two 4-meter class optical telescopes at Devasthal located in Nainital, India. After successful installation of the 3.6-m modern new technology Devasthal Optical Telescope (DOT) ...

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