IIA Institutional Repository: Recent submissions

  • Optical Spectroscopy of the Recurrent Nova RS Ophiuchi - from the Outburst of 2006 to Quiescence 
    Mondal, Anindita; Anupama, G. C; Kamath, U. S; Das, Ramkrishna; Selvakumar, G; Mondal, Soumen (Oxford University Press on behalf of the Royal Astronomical Society, 2018-03)
    Optical spectra of the 2006 outburst of RS Ophiuchi beginning one day after discovery to over a year after the outburst are presented here. The spectral evolution is found to be similar to that in previous outbursts. The ...
  • Correlation between sunspot number and Ca II K emission index 
    Bertello, L; Pevtsov, A; Tlatov, A; Singh, J (Springer, 2016-11)
    Long-term synoptic observations in the resonance line of Ca II K constitute a fundamental database for a variety of retrospective analyses of the state of the solar magnetism. Synoptic Ca II K observations began in late ...
  • Flux emergence in the solar active region NOAA 11158: the evolution of net current 
    Vemareddy, P; Venkatakrishnan, P; Karthikreddy, S (IOP Publishing, 2015-09)
    We present a detailed investigation of the evolution of observed net vertical current using a time series of vector magnetograms of the active region (AR) NOAA 11158 obtained from the Helioseismic and Magnetic Imager. We ...
  • Highly Reddened Type Ia Supernova SN 2004ab: Another Case of Anomalous Extinction 
    Chakradhari, N. K; Sahu, D. K; Anupama, G. C; Prabhu, T. P (Oxford University Press on behalf of the Royal Astronomical Society, 2018-02)
  • Automated Detection of Coronal Mass Ejections in Stereo Heliospheric Imager Data 
    Pant, V; Willems, S; Rodriguez, L; Mierla, M; Banerjee, D; Davies, J. A (IOP Publishing, 2016-12-10)
    We present deep Very Large Array imaging of 3C 273 in order to determine the diffuse, large scale radio structure of this famous radio-loud quasar. Diffuse extended structure (radio lobes) is detected for the first time ...
  • Constraints of the Physics of Low-Mass AGB Stars from CH and CEMP Stars 
    Cristallo, S; Karinkuzhi, D; Goswami, A; Piersanti, L; Gobrecht, D (IOP Publishing, 2016-12-20)
    We analyze a set of published elemental abundances from a sample of CH stars which are based on high resolution spectral analysis of ELODIE and SUBARU/HDS spectra. All the elemental abundances were derived from local ...
  • H0 from ten well-measured time delay lenses 
    Rathna Kumar, S; Stalin, C. S; Prabhu, T. P (EDP Sciences, 2015-08)
    In this work, we present a homogeneous curve-shifting analysis using the difference-smoothing technique of the publicly available light curves of 24 gravitationally lensed quasars, for which time delays have been reported ...
  • Stara -Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau 
    Guo, Zhen; Herczeg, Gregory J; Jose, J; Fu, Jianning; Chiang, Po-Shih; Grankin, Konstantin; Michel, R; Yadav, Ram Kesh; Liu, Jinzhong; Chen, Wen-Ping; Li, Gang; Xue, Huifang; Niu, Hubiao; Subramaniam, A; Sharma, Saurabh; Prasert, Nikom; Flores-Fajardo, Nahiely; Castro, Angel; Altamirano, Liliana (IOP Publishing, 2018-01)
    The variability of young stellar objects is mostly driven by star – disk interactions. In long-term photometric monitoring of the accreting T Tauri star GI Tau, we detect extinction events with typical depths ...
  • VLTI-AMBER velocity-resolved aperture-synthesis imaging of η· Carinae with a spectral resolution of 12 000 
    Weigelt, G; Hofmann, K. H; Schertl, D; Clementel, N; Corcoran, M. F; Damineli, A; De Wit, W. J; Grellmann, R; Groh, J; Guieu, S; Gull, T; Heininger, M; Hillier, D. J; Hummel, C. A; Kraus, S; Madura, T; Mehner, A; Merand, A; Millour, F; Moffat, A. F. J; Ohnaka, K; Patru, F; Petrov, R. G; Sridharan, R; Richardson, N. D; Rivinius, T; Scholler, M; Teodoro, M; Wittkowski, M (EDP Sciences, 2016-10)
    Context. The mass loss from massive stars is not understood well. η Carinae is a unique object for studying the massive stellar wind during the luminous blue variable phase. It is also an eccentric binary with a period of ...
  • Detecting exomoons around self-luminous giant exoplanets through polarization 
    Sengupta, S; Marley, M. S (IOP Publishing, 2016-06-20)
    Many of the directly imaged self-luminous gas-giant exoplanets have been found to have cloudy atmospheres. Scattering of the emergent thermal radiation from these planets by the dust grains in their atmospheres should ...
  • Performance analysis of free space optical communication in open-atmospheric turbulence conditions with beam wandering compensation control 
    Anthonisamy, Arockia Bazil Raj; Durairaj, Padmavathi; Lancelot, J. P (IET, 2016-06-16)
    Among various atmospheric effects, beam wandering is the main cause for the major power loss in free space optical communication (FSOC) which cannot be resolved without incorporating the beam wandering compensation (BWC) ...
  • Age aspects of habitability 
    Safonova, M; Murthy, J; Shchekinov, Yu. A (Cambridge University Press, 2016-04)
    A ‘habitable zone’ of a star is defined as a range of orbits within which a rocky planet can support liquid water on its surface. The most intriguing question driving the search for habitable planets is whether they host ...
  • Taming the Electronic Structure of Diradicals through the Window of Computationally Cost Effective Multireference Perturbation Theory 
    Sinha Ray, Suvonil; Ghosh, A; Chattopadhyay, S; Chaudhuri, R. K (American Chemical Society, 2016-07-28)
    Recently a state-specific multireference perturbation theory (SSMRPT) with an improved virtual orbitals complete active space configuration interaction (IVO-CASCI) reference function has been proposed for treating electronic ...
  • Exploring the optical behaviour of a Type Iax supernova SN 2014dt 
    Singh, M; Misra, K; Sahu, D. K; Dastidar, R; Gangopadhyay, A; Bose, S; Srivastav, S; Anupama, G. C; Chakradhari, N. K; Brajesh Kumar; Kumar, B; Pandey, S. B (Oxford University Press on behalf of the Royal Astronomical Society, 2018-02)
    We present optical photometric (up to ∼ 410 d since B max ) and spectroscopic (up to ∼ 157 d since B max ) observations of a Type Iax supernova (SN) 2014dt located in M61. SN 2014dt is one of the brightest and ...
  • Characterization of X-ray flare properties of AB Dor 
    Lalitha, S (International Astronomical Union, 2015-08)
    The strong similarities between the flares observed on the Sun and in low mass stars has raised question regarding dynamo in these stars. Using the Sun as a prototype, one may be able to address this. In this paper, we ...
  • Relationships between fluid vorticity, kinetic helicity, and magnetic field on small-scales (quiet-network) on the sun 
    Sangeetha, C. R; Rajaguru, S. P (IOP Publishing, 2016-06-20)
    We derive horizontal fluid motions on the solar surface over large areas covering the quiet-Sun magnetic network from local correlation tracking of convective granules imaged in continuum intensity and Doppler velocity by ...
  • Ejecta curtain radiative transfer modeling for probing its geometry and dust optical properties 
    Shalima, P; Wada, K; Kimura, H (Elsevier, 2015-10)
    An ejecta curtain is produced as a result of impact cratering of celestial bodies that excavates and ejects their surface and underground material. Since ejecta particles are thought to reflect the interior materials and ...
  • Balloon UV experiments for astronomical and atmospheric observations 
    Sreejith, A. G; Mathew, J; Mayuresh, Sarpotdar; Nirmal, K; Ambily, S; Prakash, A; Safonova, M; Murthy, J (SPIE-The International Society for Optical Engineering, 2016-08)
    The ultraviolet (UV) window has been largely unexplored through balloons for astronomy. We discuss here the development of a compact near-UV spectrograph with fiber optics input for balloon flights. It is a modified ...
  • Topological and statistical properties of nonlinear force-free fields 
    Mangalam, A; Prasad, A (Elsevier B.V, 2018-01)
    We use our semi-analytic solution of the nonlinear force-free field equation to construct three-dimensional magnetic fields that areapplicable to the solar corona and study their statistical properties for estimating the ...
  • Developing scanning-slit spectrograph for imaging the Sun 
    Pruthvi, H; Ramesh, K. B; Dhara, Sajal Kumar; Ravindra, B (SPIE--The International Society for Optical Engineering, 2016-08)
    For moderate resolution spectroscopy of the Sun, an imaging spectrograph is being developed at Indian Institute of Astrophysics. With this instrument images of the region of interest of the Sun can be obtained with low ...

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