IIA Institutional Repository: Recent submissions

  • Nebula around R Corona Borealis 
    Kameswara Rao, N; Lambert, David L (International Astronomical Union, 2012-08-30)
    The star R Corona Borealis (R CrB) shows forbidden lines of [O II], [N II], and [S II] during the deep minimum when the star is fainter by about 8 to 9 magnitudes from normal brightness, suggesting the presence of nebular ...
  • Understanding jets from sources straddling the Fanaroff-Riley divide 
    Kharb, P; Stanley, E; Lister, M; Marshall, H; O'Dea, C; Baum, S (Cambridge University Press, 2015-03)
    Results from Chandra-HST-VLA observations of 13 hybrid sources are presented. Data from ten sources in the literature are analysed along with new data from three hybrid blazars belonging to the MOJAVE sample. Studies of ...
  • Association of Supergranule Mean Scales with Solar Cycle Strengths and Total Solar Irradiance 
    Mandal, Sudip; Chatterjee, Subhamoy; Banerjee, D (IOP Publishing, 2018-09)
    We analyze the long-term behavior of the supergranule scale parameter, in active regions (ARs) and quiet regions (QRs), using the Kodaikanal digitized data archive. This database provides century-long daily full ...
  • S stars and s-process in the Gaia era I. Stellar parameters and chemical abundances in a sub-sample of S stars with new MARCS model atmospheres 
    Shetye, S; Van Eck, S; Jorissen, A; Van Winckel, H; Siess, L; Goriely, S; Escorza, A; Drisya, K; Plez, B (EDP Sciences, 2018-12)
    Context. S stars are transition objects between M-type giants and carbon stars on the asymptotic giant branch (AGB). They are characterized by overabundances of s-process elements. Roughly half of them are enhanced in ...
  • Temporal asymmetry in aerosol optical characteristics: A case study at a high-altitude station, Hanle, in Ladakh region 
    Shantikumar, N. S; Bagare, S. P; Srivastava, A. K; Kanawade, V. P; Rajendra, B. S; Padhy, S. K (Elsevier, 2014-12)
    Diurnal features of aerosol optical depth (AOD) at a high-altitude station, Hanle (4500 m amsl) in the western Himalayas, were studied using direct/diffuse solar irradiance measurement from a Skyradiometer (Prede) during ...
  • Observations of photospheric vortical motions during the early stage of filament eruption 
    Sajal Kumar Dhara; Ravindra, B; Banyal, R. K (Springer, 2014-12)
    Solar filaments/prominences exhibit rotational motion during different phases of their evolution from their formation to eruption. We have observed the rotational/vortical motion in the photosphere near the ends of ten ...
  • An estimate of the magnetic field strength associated with a solar coronal mass ejection from low frequency radio observations 
    Sasikumar Raja, K; Ramesh, R; Hariharan, K; Kathiravan, C; Wang, T. J (IOP Publishing, 2014-11-20)
    We report ground based, low frequency heliograph (80 MHz), spectral (85-35 MHz), and polarimeter (80 and 40 MHz) observations of drifting, non-thermal radio continuum associated with the "halo" coronal mass ejection that ...
  • Relativistic many-body analysis of the electric dipole moment of 223 Rn 
    Sahoo, B. K; Singh, Yashpal; Das, B. P (American Physical Society, 2014-11)
    We report the results of our ab initio relativistic many-body calculations of the electric dipole moment (EDM) d(A) arising from the electron-nucleus tensor-pseudotensor (T-PT) interaction, the interaction of the nuclear ...
  • Deep optical survey of the stellar content of Sh2-311 region 
    Yadav, Ram Kesh; Pandey, A. K; Sharma, Saurabh; Jose, J; Ogura, K; Kobayashi, N; Samal, M. R; Eswaraiah, C; Chandola, H. C (Elsevier, 2015-01)
    The stellar content in and around Sh2-311 region have been studied using the deep optical observations as well as near-infrared (NIR) data from 2MASS. The region contains three clusters, viz. NGC 2467, Haffner 18 and Haffner ...
  • Aerosol radiative forcing over a high-altitude station Merak, in the trans-Himalayan region during advection of anthropogenic events from the Indo-Gangetic Plain 
    Shantikumar, N. S; Bagare, S. P; Srivastava, A. K; Sohn, B. J; Song, H.-J; Larson, E (Elsevier B.V, 2014-12)
    Advection of anthropogenic aerosols from the Indo-Gangetic Plain (IGP) and dust aerosols from distant deserts towards a high-altitude station Merak, in the trans-Himalayan region are reported during June–July 2011. In order ...
  • Speckle imaging with hypertelescopes 
    Surya, A; Saha, S. K; Labeyrie, A (Oxford University Press on behalf of the Royal Astronomical Society, 2014-09-01)
    Optical stellar interferometers have demonstrated milliarcsecond resolution with few apertures spaced hundreds of metres apart. To obtain rich direct images, many apertures will be needed, for a better sampling of the ...
  • Polarimetric analysis of the Thirty Meter Telescope (TMT) for modeling instrumental polarization characteristics 
    Atwood, J; Skidmore, W; Anupama, G. C; Ramya, M. Anche; Krishna Reddy; Sen, Asoke (SPIE--The International Society for Optical Engineering, 2014-08)
    The Thirty Meter Telescope (TMT) will be called upon to support a polarimetric observing capability. Many different observing programs covering a range of different science areas are being considered for the TMT and a model ...
  • An Estimate of the Coronal Magnetic Field near a Solar Coronal Mass Ejection from Low-frequency Radio Observations 
    Hariharan, K; Ramesh, R; Kishore, P; Kathiravan, C; Gopalswamy, N (IOP Publishing, 2014-11-01)
    We report ground-based, low-frequency (<100 MHz) radio imaging, spectral, and polarimeter observations of the type II radio burst associated with the solar coronal mass ejection (CME) that occurred on 2013 May 2. The ...
  • Optical observations of the fast declining Type Ib supernova iPTF13bvn 
    Srivastav, S; Anupama, G. C; Sahu, D. K (Oxford University Press on behalf of the Royal Astronomical Society, 2014-12-01)
    We present optical UBVRI photometry and medium resolution spectroscopy of the Type Ib supernova iPTF13bvn, spanning a phase of ∼−13 d to +71 d with respect to B-band maximum. The post-maximum decline rates indicate a fast ...
  • Application of relativistic coupled-cluster theory to the effective electric field in YbF 
    Abe, M; Gopakumar, G; Hada, M; Das, B. P; Tatewaki, H; Mukherjee, D (The American Physical Society, 2014-08)
    An accurate determination of the effective electric field (Eeff) in YbF is important as it can be combined with the results of future experiments to give an improved new limit for the electric dipole moment of the electron. ...
  • Quantum phases of attractive bosons on a Bose-Hubbard ladder with three-body constraint 
    Singh, Manpreet; Mishra, T; Pai, Ramesh V; Das, B. P (The American Physical Society, 2014-07)
    We obtain the complete quantum phase diagram of bosons on a two-leg ladder in the presence of attractive onsite and repulsive interchain nearest-neighbor interactions by imposing the onsite three-body constraint. We find ...
  • Relativistic equation-of-motion coupled-cluster method for the double-ionization potentials of closed-shell atoms 
    Pathak, H; Ghosh, A; Sahoo, B. K; Das, B. P; Vaval, N; Pal, S (The American Physical Society, 2014-07)
    We report the implementation of the relativistic equation-of-motion coupled-cluster method to calculate the double-ionization spectra (DI-EOMCC) of the closed-shell atomic systems. This method is employed to calculate the ...
  • Observational Aspects Of Core Collapse Supernovae 
    Gurugubelli, Uday Kumar (Indian Institute of Astrophysics, 2010-11)
    The discovery of several bright supernovae (SNe) in recent years has evoked a great deal of interest in these objects. The study of these objects are of importance not only as probes to the end stages of stellar evolution, ...
  • Discovery of Dramatic Optical Variability in SDSS J1100+4421: A Peculiar Radio-loud Narrow-line Seyfert 1 Galaxy? 
    Tanaka, M; Morokuma, T; Itoh, R; Akitaya, H; Tominaga, N; Saito, Y; Stawarz, L; Tanaka, Y, T; Gandhi, P; Ali, G; Aoki, T; Contreras, C; Doi, M; Essam, A; Hamed, G; Hsiao, E. Y; Iwata, I; Kawabata, K. S; Kawai, N; Kikuchi, Y; Kobayashi, N; Kuroda, D; Maehara, H; Matsumoto, E; Mazzali, P. A; Minezaki, T; Mito, H; Miyata, T; Miyazaki, S; Mori, K; Moritani, Y; Morokuma-Matsui, Kana; Morrell, N; Nagao, T; Nakada, Y; Nakata, F; Noma, C; Ohsuga, K; Okada, N; Phillips, M. M; Pian, E; Richmond, M. W; Sahu, D. K; Sako, S; Sarugaku, Y; Shibata, T; Soyano, T; Stritzinger, M. D; Tachibana, Y; Taddia, F; Takaki, K; Takey, Ali; Tarusawa, K; Ui, T; Ukita, N; Urata, Y; Walker, E. S; Yoshii, T (IOP Publishing, 2014-10-01)
    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. ...
  • iPTF13bvn: The First Evidence of a Binary Progenitor for a Type Ib Supernova 
    Bersten, M. C; Benvenuto, O. G; Folatelli, G; Nomoto, K; Kuncarayakti, H; Srivastav, Shubham; Anupama, G. C; Quimby, R; Sahu, D. K (IOP Publishing, 2014-10)
    The recent detection in archival Hubble Space Telescope images of an object at the location of supernova (SN) iPTF13bvn may represent the first direct evidence of the progenitor of a Type Ib SN. The object's photometry was ...

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