IIAP Publications: Recent submissions

  • Simulation of the small-scale magnetism in main-sequence stellar atmospheres 
    Salhab, R. G; Steiner, O; Berdyugina, S. V; Freytagz, B; Rajaguru, S. P; Steffen, M (EDP Sciences, 2018-06)
    Context. Observations of the Sun tell us that its granular and subgranular small-scale magnetism has significant consequences for global quantities such as the total solar irradiance or convective blueshift of spectral ...
  • Polarization of Trappist-1 by the Transit of Its Planets 
    Sengupta, S (IOP Publishing, 2018-07-01)
    Being the first, and currently the only, multiple planet hosting dwarf star that is sufficiently cool to form condensate clouds in its atmosphere, Trappist-1 provides a unique opportunity to test the efficiency of image ...
  • Optical spectroscopic and polarization properties of 2011 outburst of the recurrent nova T Pyxidis 
    Pavana, M; Ramya, M. Anche; Anupama, G. C; Ramaprakash, A. N; Selvakumar, G (EDP Sciences, 2019-02)
    Aims. We aim to study the spectroscopic and ionized structural evolution of T Pyx during its 2011 outburst, and also study the variation in degree of polarization during its early phase. Methods. Optical spectroscopic data ...
  • Application of the finite-field coupled-cluster method to calculate molecular properties relevant to electron electric-dipole-moment searches 
    Abe, M; Prasannaa, V. S; Das, B. P (The American Physical Society, 2018-03)
    Heavy polar diatomic molecules are currently among the most promising probes of fundamental physics. Constraining the electric dipole moment of the electron (eEDM), in order to explore physics beyond the standard model, ...
  • Strong nonlocality variations in a spherical mean-field dynamo 
    Brandenburg, Axel; Chatterjee, Piyali (WILEY-VCH Verlag GmbH & Co., 2018-02)
    To explain the large-scale magnetic field of the sun and other bodies, the mean-field dynamo theory is commonly applied, where one solves the averaged equations for the mean magnetic field. However, the standard approach ...
  • Analysis of polarization introduced due to the telescope optics of the Thirty Meter Telescope 
    Ramya, M. Anche; Sen, A; Anupama, G. C; Sankarasubramanian, K; Skidmore, W (SPIE-The International Society for Optical Engineering, 2018-01)
    An analytical model has been developed to estimate the polarization effects, such as instrumental polarization (IP), crosstalk (CT), and depolarization, due to the optics of the Thirty Meter Telescope. These are estimated ...
  • Dissecting galaxies: separating star formation, shock excitation and AGN activity in the central region of NGC 613 
    Davies, R. L; Groves, B; Kewley, L. J; Medling, A. M; Shastri, P; Maithil, J; Kharb, P; Banfield, J; Longbottom, F; Dopita, M. A; Hampton, E. J; Scharwachter, J; Sutherland, R; Jin, C; Zaw, I; Juneau, S (Oxford University Press on behalf of the Royal Astronomical Society, 2017-08)
    The most rapidly evolving regions of galaxies often display complex optical spectra with emission lines excited by massive stars, shocks and accretion on to supermassive black holes. Standard calibrations (such as for ...
  • Design, development, and validation of a segment support actuator for the prototype segmented mirror telescope 
    Deshmukh, P. G; Mandal, A; Parihar, P. S; Nayak, D; Mishra, Deepta Sundar (SPIE-The International Society for Optical Engineering, 2018-01)
    Segmented mirror telescopes (SMT) are built using several 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 actuators ...
  • Abundance Analyses of the New R Coronae Borealis Stars ASAS-RCB-8 and ASAS-RCB-10 
    Hema, B. P; Pandey, G; Kamath, D; Kameswara Rao, N; Lambert, D. L; Woolf, V. M (IOP Publishing, 2017-10)
    Abundance analyses of the two newly discovered R Coronae Borealis (RCB) stars ASAS-RCB-8 and ASAS-RCB-10 were conducted using high-resolution optical spectra and model atmospheres. Their chemical compositions place the pair ...
  • Dynamic Loading Assembly for Testing Actuators of Segmented Mirror Telescope 
    Prasanna Deshmukh; Parihar, P. S; Balasubramaniam, K. A; Mishra, Deepta Sundar; Mahesh, P. K (World Scientific Publishing Co., 2017-09)
    Upcoming large telescopes are based on Segmented Mirror Telescope (SMT) technology which uses small hexagonal mirror segments placed side by side to form the large monolithic surface. The segments alignment needs to be ...
  • Period changes in the RR Lyrae stars of NGC 6171 (M107) 
    Arellano Ferro, A; Rosenzweig, P; Luna, A; Deras, D; Muneer, S; Giridhar, S; Michel, R (WILEY-VCH Verlag GmbH & Co., 2018-02)
    Based on photometric data obtained between 1935 and 2017, O −C diagrams were built for 22 RR Lyrae stars in the globular cluster NGC 6171, leading to the discovery of secular period changes in four variables for which we ...
  • Dark energy constraints on masses and sizes of large scale cosmic structures 
    Rebecca, L; Arun, K; Sivaram, C (Springer, 2018-07)
    The requirement that their gravitational binding self-energy density must at least equal the background repulsive dark energy density for large scale cosmic structures implies a mass-radius relation of M/R2 ≈ 1 g/cm2, as ...
  • A peculiar multiwavelength flare in the blazar 3C 454.3 
    Gupta, A. C; Mangalam, A; Wiita, J. Paul; Kushwaha, P; Gaur, H; Zhang, H; Gu, M. F; Liao, M; Dewangan, G. C; Ho, L. C; Mohan, P; Umeura, M; Sasada, M; Volvach, A. E; Agarwal, A; Aller, M. F; Aller, H. D; Bachev, R; Lahteenmaki, A; Semkov, E; Strigachev, A; Tornikoski, M; Volvach, L. N (Oxford University Press on behalf of the Royal Astronomical Society, 2017-11)
    The blazar 3C 454.3 exhibited a strong flare seen in γ -rays, X-rays and optical/near-infrared bands during 2009 December 3–12. Emission in the V and J bands rose more gradually than did the γ -rays and soft X-rays, ...
  • Variations in Ca-K line profiles and Ca-K line features as a function of latitude and solar cycle during the 20th century 
    Singh, J; Priyal, M; Sindhuja, G; Ravindra, B (Cambridge University Press, 2018-02)
    The analysis of the Ca-K line spectra as a function of latitude and integrated over the visible disk obtained during the period of 1989–2011 at the Kodaikanal Solar Tower Telescope shows that the FWHM of the K1 distribution ...
  • Flux tube model in the solar atmosphere 
    Sen, Samrat; Mangalam, A (Cambridge University Press, 2018-02)
    We construct two classes of the magnetohydrostatic equilibria of the axisymmetric flux tubes with twisted magnetic fields in the stratified solar atmosphere that span from the photosphere to the transition region. We built ...
  • Unusual long-term low-activity states of EGRET blazars in the Fermi era 
    Bhattacharya, Debbijoy; Mohana A, K; Gulati, S; Bhattacharyya, Subir; Bhatt, N; Sreekumar, P; Stalin, C. S (Oxford University Press on behalf of the Royal Astronomical Society, 2017-11)
    We examine the long-term (∼10 years) γ-ray variability of blazars observed by the Energetic Gamma Ray Experiment Telescope (EGRET) and Fermi and find that 10 EGRET-detected flat-spectrum radio quasars (FSRQs) were not ...
  • Energy distribution of solar flare events 
    Sen, Samrat; Mangalam, A; Ramesh, R (Cambridge University Press, 2018-02)
    The coronal field typically reorganizes itself to attain a force-free field configuration. We have evaluated the power law index of the energy distribution f(E) = f0E−α by using a model of relaxation incorporating ...
  • Investigating the in-flight performance of the UVIT payload on AstroSat 
    Rahna, P. T; Murthy, J; Safonova, M; Sutaria, F. K; Gudennavar, S. B; Bubbly, S. G (Oxford University Press on behalf of the Royal Astronomical Society, 2017-11)
    We have studied the performance of the Ultraviolet Imaging Telescope payload on AstroSat and derived a calibration of the far-ultraviolet (FUV) and near-ultraviolet (NUV) instruments on board. We find that the sensitivity ...
  • Unusual bright filaments on the sun on 1926 February 22 
    Royds, T (Royal Astronomical Society, 1926)
  • Search for variable stars in the open cluster NGC 2509 
    Dar, A. A; Parihar, P. S; Saleh, P; Malik, M. A (Elsevier B.V, 2018-10)
    This work presents the first photometric variability survey of the open cluster NGC 2509 carried out in February, 2017. Data of four nights was analysed by ensemble photometry technique, using 1k × 1k CCD and 1.3 m telescope ...

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