IIA Institutional Repository: Recent submissions

  • SN 2013ej: a type IIL supernova with weak signs of interaction 
    Bose, S; Sutaria, F. K; Kumar, B; Duggal, C; Misra, K; Brown, P. J; Singh, M; Dwarkadas, V; York, D. G; Chakraborti, S; Chandola, H. C; Dahlstrom, J; Ray, A; Safonova, M (IOP Publishing, 2015-06)
    We present optical photometric and spectroscopic observations of SN 2013ej. It is one of the brightest Type II supernovae (SNe II) exploded in a nearby (∼10 Mpc) galaxy, NGC 628. The light-curve characteristics are similar ...
  • Contribution of Field Strength Gradients to the Net Vertical Current of Active Regions 
    Vemareddy, P (IOP Publishing, 2017-12)
    We examined the contribution of fi eld strength gradients for the degree of net vertical current ( NVC ) neutralization in active regions ( ARs ) . We used photospheric vector magnetic fi eld observations of ...
  • Leptonic and hadronic modeling of Fermi-LAT hard spectrum quasars and predictions for high-energy polarization 
    Paliya, Vaidehi S; Zhang, H; Bottcher, M; Ajello, M; Domi­nguez, A; Joshi, M; Hartmann, D; Stalin, C. S (IOP Publishing, 2018-08)
    We present the results of a study of the time-averaged spectral energy distributions (SEDs) of eight flat spectrum radio quasars (FSRQs) present in the second catalog of high energy sources detected beyond 50 GeV by the ...
  • Helioseismic inversion to infer the depth profile of solar meridional flow using spherical born kernels 
    Mandal, K; Hanasoge, S. M; Rajaguru, S. P; Antia, H. M (IOP Publishing, 2018-08)
    Accurate inferences of solar meridional flow are crucial for understanding solar dynamo processes. Wave travel times, as measured on the surface, will change if the waves encounter perturbations, e.g., in the sound speed ...
  • The needle in the 100 deg2 haystack: uncovering afterglows of fermi GRBs with the palomar transient factory 
    Singer, L. P; Kasliwal, M. M; Cenko, S. B; Perley, D. A; Anderson, G. E; Anupama, G. C; Arcavi, I; Bhalerao, V; Bue, B. D; Cao, Y; Connaughton, V; Corsi, A; Cucchiara, A; Fender, R. P; Fox, D. B; Gehrels, N; Goldstein, A; Gorosabel, J; Horesh, A; Hurley, K; Johansson, J; Kann, D. A; Kouveliotou, C; Huang, K; Kulkarni, S. R; Masci, F; Nugent, P; Rau, A; Rebbapragada, U. D; Staley, T. D; Svinkin, D; Thone, C. C; de Ugarte Postigo, A; Urata, Y; Weinstein, A (IOP Publishing, 2015-06)
    The Fermi Gamma-ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi ...
  • Kinematics of and emission from helically orbiting blobs in a relativistic magnetized jet 
    Mohan, Prashanth; Mangalam, A (IOP Publishing, 2015-07-01)
    We present a general relativistic (GR) model of jet variability in active galactic nuclei due to orbiting blobs in helical motion along a funnel or cone-shaped magnetic surface anchored to the accretion disk near the black ...
  • Tensor Minkowski Functionals for random fields on the sphere 
    Pravabati, C; Yogendran, K. P; Joby, P. K; Vidhya, G; Appleby, S; Park, C (IOP Publishing, 2017-12)
    We generalize the translation invariant tensor-valued Minkowski Functionals which are defined on two-dimensional flat space to the unit sphere. We apply them to level sets of random fields. The contours enclosing ...
  • Characterization of the HD 219134 multi-planet system I. Observations of stellar magnetism, wind, and high-energy flux 
    Folsom, C. P; Fossati, L; Wood, B. E; Sreejith, A. G; Cubillos, P. E; Vidotto, A. A; Alecian, E; Girish, V; Lichtenegger, H; Murthy, J; Petit, P; Valyavin, G (Oxford University Press on behalf of the Royal Astronomical Society, 2018-12)
    HD 219134 hosts several planets, with seven candidates reported, and the two shortest period planets are rocky (4–5 M⊕) and transit the star. Here, we present contemporaneous multiwavelength observations of the star ...
  • High-resolution spectroscopy of the relatively hydrogen-poor metal-rich giants in the globular cluster ω centauri 
    Hema, B. P; Pandey, G; Srianand, R (IOP Publishing, 2018-09)
    High-resolution optical spectra are analyzed for two of the four metal-rich, mildly hydrogen-poor or helium-enhanced giants discovered by Hema & Pandey, along with their comparison normal (hydrogen-rich) giants. The strengths ...
  • Target selection for the SDSS-III marvels survey 
    Paegert, M; Stassun, K. G; De Lee, N; Pepper, J; Fleming, S. W; Sivarani, T; Mahadevan, S; Mack, C. E; Dhital, S; Hebb, L; Ge, J (IOP Publishing, 2015-06)
    We present the target selection process for the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the Sloan Digital Sky Survey (SDSS) III. MARVELS is a medium-resolution (R ∼ 11,000) ...
  • UVIT imaging of WLM: demographics of star-forming regions in the nearby dwarf irregular galaxy 
    Mondal, Chayan; Subramaniam, A; George, K (IOP Publishing, 2018-09)
    We present a study of star-forming regions and their demographics in the nearby dwarf irregular galaxy WLM using Ultraviolet Imaging Telescope (UVIT) multiband observations in three filters, F148W, N245M, and N263M. We ...
  • Strong near-infrared carbon in the type Ia supernova iPTF13ebh 
    Hsiao, E. Y; Burns, C. R; Contreras, C; Hoflich, P; Sand, D; Marion, G. H; Phillips, M. M; Stritzinger, M; Gonzalez-Gaitan, S; Mason, R. E; Folatelli, G; Parent, E; Gall, C; Amanullah, R; Anupama, G. C; Arcavi, I; Banerjee, D. P. K; Beletsky, Y; Blanc, G. A; Bloom, J. S; Brown, P. J; Campillay, A; Cao, Y; De Cia, A; Diamond, T; Freedman, W. L; Gonzalez, C; Goobar, A; Holmbo, S; Howell, D. A; Johansson, J; Kasliwal, M. M; Kirshner, R. P; Krisciunas, K; Kulkarni, S. R; Maguire, K; Milne, P. A; Morrell, N; Nugent, P. E; Ofek, E. O; Osip, D; Palunas, P; Perley, D. A; Persson, S. E; Piro, A. L; Rabus, M; Roth, M; Schiefelbein, J. M; Srivastav, S; Sullivan, M; Suntzeff, N. B; Surace, J; Wozniak, P. R; Yaron, O (EDP Sciences, 2015-06)
    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated ...
  • Latitude Distribution of Sunspots: Analysis Using Sunspot Data and a Dynamo Model 
    Mandal, Sudip; Karak, B. B; Banerjee, D (2017-12)
    In this paper, we explore the evolution of sunspot latitude distribution and explore its relations with the cycle strength. With the progress of the solar cycle, the distributions in two hemispheres from mid-latitudes ...
  • Star clusters in the magellanic clouds II. age-dating, classification, and spatio-temporal distribution of the SMC clusters 
    Nayak, P. K; Subramaniam, A; Choudhury, S; Sagar, R (EDP Sciences, 2018-08)
    Aims. We aim to estimate the age and reddening parameters of already identified star clusters within the Small Magellanic Cloud (SMC) in a consistent way using available photometric data, classify them based on their mass ...
  • The recent signs of total column ozone recovery over mid-latitudes: the effects of the montreal protocol mandate 
    Shantikumar, S. N; Vemareddy, P; Song, H. -J (Elsevier B.V, 2018-10)
    After successful implementation of the Montreal Protocol, total ozone column (TOC) has considerably increased since the mid 1990s. However, the recovery is weak and statistically non-significant particularly at low-latitudes ...
  • Hemispheric asymmetry of sunspot area in solar cycle 23 and rising phase of solar cycle 24: comparison of three data sets 
    Ravindra, B; Javaraiah, J (2015-08)
    Analysis of long-term solar data from different observatories is required to compare and confirm the various level of solar activity in depth. In this paper, we study the north–south asymmetry of monthly mean sunspot area ...
  • Signatures of the Impact of Flare-Ejected Plasma on the Photosphere of a Sunspot Light Bridge 
    Felipe, T; Collados, M; Khomenko, E; Rajaguru, S. P; Franz, M; Kuckein, C; Asensio Ramos, A (EDP Sciences, 2017-12)
    Aims. We investigate the properties of a sunspot light bridge, focusing on the changes produced by the impact of a plasma blob ejected from a C-class flare. Methods. We observed a sunspot in active region NOAA 12544 ...
  • A novel probe of ionized bubble shape and size statistics of the epoch of reionization using the contour Minkowski tensor 
    Akanksha, K; Pravabati, C; Appleby, S; Park, C (IOP Publishing, 2018-10)
    We employ the rank-2 contour Minkowski tensor in two dimensions to probe length and time scales of ionized bubbles during the epoch of reionization. We demonstrate that ionized bubbles are not circular, and hence not ...
  • ASASSN-14dq: A fast-declining type II-P Supernova in a low-luminosity host galaxy 
    Singh, A; Srivastav, S; Brajesh Kumar; Anupama, G. C; Sahu, D. K (Oxford University Press on behalf of the Royal Astronomical Society, 2018-10)
    Optical broadband (UBVRI) photometric and low-resolution spectroscopic observations of the Type II-P supernova (SN) ASASSN-14dq are presented. ASASSN-14dq exploded in a low-luminosity/metallicity host galaxy UGC 11860, the ...
  • Coronal magnetic field measurements using forbidden emission lines 
    Megha, A; Sampoorna, M; Nagendra, K. N; Sankarasubramanian, K (Cambridge University Press, 2018-02)
    The polarization measurement of coronal forbidden emission lines is the most promising method of determining the direction of magnetic fields in the corona. A classical theory for the forbidden lines was presented in Megha ...

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