IIA Institutional Repository: Recent submissions

  • Temporal correlation between the optical and γ-ray flux variations in the blazar 3C 454.3 
    Rajput, Bhoomika; Stalin, C. S; Sahayanathan, S; Rakshit, S; Amit Kumar Mandal (Oxford University Press on behalf of the Royal Astronomical Society, 2019-06)
    Blazars show optical and γ-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data ...
  • Cosmic evolution of AGN using self-consistent black hole energetics 
    Mangalam, A (Astronomical Society of India, 2015)
    We consider a model that takes into account the mass and spin accreted by the hole and the angular momentum torque due to an electrodynamical jet. The spin evolution is calculated with and without accretion; if the accretion ...
  • High-resolution, high-sensitivity, ground-based solar spectropolarimetry with a new fast imaging polarimeter: I .Prototype characterization 
    Iglesias, F. A; Feller, A; Nagaraju, K; Solanki, S. K (EDP Sciences, 2016-06)
    Remote sensing of weak and small-scale solar magnetic fields is of utmost relevance when attempting to respond to a number of important open questions in solar physics. This requires the acquisition of spectropolarimetric ...
  • Tracking galaxy evolution through low-frequency radio continuum observations using SKA and citizen-science research using multi-wavelength data 
    Hota, A; Konar, C; Stalin, C. S; Vaddi, Sravani; Mohanty, Pradeepta K; Dabhade, Pratik; Arun, Sai; Bhoga, Dharmik; Rajoria, Megha; Sethi, Sagar (Indian Academy of Sciences, 2016-12)
    We present a brief review of progress in the understanding of general spiral and elliptical galaxies, through merger, star formation and AGN activities. With reference to case studies performed with the GMRT, we highlight ...
  • Silicon depletion in the interstellar medium 
    Haris, U; Parvathi, V. S; Gudennavar, S. B; Bubbly, S. G; Murthy, J; Sofia, U. J (IOP Publishing, 2016-07)
    We report interstellar silicon ( Si ) depletion and dust-phase column densities of Si along 131 Galactic sight lines using archival observations. The data were corrected for differences in the assumed oscillator ...
  • Probing magnetic fields with square kilometre array and its precursors 
    Roy, S; Sur, Sharanya; Subramanian, K; Mangalam, A; Seshadri, T. R; Chand, H (Indian Academy of Sciences, 2016-12)
    Origin of magnetic fields, its structure and effects on dynamical processes in stars to galaxies are not well understood. Lack of a direct probe has remained a problem for its study. The first phase of Square Kilometre ...
  • Solar wind associated with near equatorial coronal Hole 
    Hegde, M; Hiremath, K. M; Doddamani, V. H; Gurumath, S. R (2015-09)
    Present study probes temporal changes in the area and radiative flux of near equatorial coronal hole associated with solar wind parameters such as wind speed, density, magnetic field and temperature. Using high temporal ...
  • A new study of the variable star population in the Hercules globular cluster (M13; NGC 6205) 
    Deras, D; Arellano Ferro, A; Lazaro, C; Bustos Fierro, I. H; Calderon, J. H; Muneer, S; Giridhar, S (Oxford University Press on behalf of the Royal Astronomical Society, 2019-06)
    We present the results from VI CCD time-series photometry of the globular cluster M13 (NGC 6205). From the Fourier decomposition of the light curves of RRab and RRc stars we found an average metallicity of [Fe/H]zw = −1.58 ...
  • SN 2016B a.k.a. ASASSN-16ab: a transitional Type II supernova 
    Dastidar, R; Misra, K; Singh, M; Sahu, D. K; Pastorello, A; Gangopadhyay, A; Tomasella, L; Benetti, S; Terreran, G; Sanwal, Pankaj; Kumar, B; Singh, A; Brajesh Kumar; Anupama, G. C; Pandey, S. B (Oxford University Press on behalf of the Royal Astronomical Society, 2019-06)
    We present photometry, polarimetry, and spectroscopy of the Type II supernova ASASSN-16ab/SN 2016B in PGC 037392. The photometric and spectroscopic follow-up commenced about 2 weeks after shock breakout and continued until ...
  • Workshop I: gender studies 
    Hennessey, E; Kurup, A; Meza-Montes, L; Shastri, P; Ghose, S (AIP Publishing, 2015-05)
    Participants in the Gender Studies workshop of the 5th IUPAP International Conference on Women in Physics discussed the gender question in science practice from a policy perspective, informed by investigations ...
  • Are H 0 and σ 8 Tensions Generic to Present Cosmological Data? 
    Bhattacharyya, Archita; Alam, Ujjaini; Pandey, Kanhaiya L; Das, Subinoy; Pal, Supratik (IOP Publishing, 2019-05-10)
    Yes, for a wide range of cosmological models (ΛCDM, non-interacting wz CDM, wz WDM, or a class of interacting DMDE). Recently there have been attempts to solve the tension between direct measurements of H0 and s8 0m W from ...
  • Measurements of atmospheric turbulence parameters at Vainu Bappu Observatory using short-exposure CCD images 
    Sreekanth Reddy, V; Banyal, R. K; Sridharan, R; Aishwarya, S (IOP Publishing, 2019-05)
    We report atmospheric turbulence parameters, namely atmospheric seeing, tilt-anisoplanatic angle (θ0) and coherence time (τ0), measured under various sky conditions, at Vainu Bappu Observatory in Kavalur. Bursts of short ...
  • High dynamic range observations of solar coronal transients at low radio frequencies with a spectro-correlator 
    Hariharan, K; Ramesh, R; Kathiravan, C; Abhilash, H. N; Rajalingam, M (IOP Publishing, 2016-02)
    A new antenna system with a digital spectro-correlator that provides high temporal, spectral, and amplitude resolutions has been commissioned at the Gauribidanur Observatory near Bangalore in India. Presently, it is used ...
  • Low-frequency radio observations of the solar corona with arcminute angular resolution: implications for coronal turbulence and weak energy releases 
    Mugundhan, V; Ramesh, R; Barve, Indrajit V; Kathiravan, C; Gireesh, G. V. S; Kharb, P; Misra, A (IOP Publishing, 2016-11-10)
    We report on the first long baseline interferometer (length ≈8 km) observations of the solar corona at 37 MHz that were carried out recently with an angular resolution of ≈1'. The results indicate that, (1) discrete radio ...
  • The eleventh and twelfth data releases of the sloan digital sky survey: final data from SDSS-III 
    Alam, S; Albareti, F. D; Prieto, C. A; Anders, F; Anderson, S. F; Anderton, T; Andrews, B. H; Armengaud, E; Aubourg, E; Bailey, S; Basu, S; Bautista, J. E; Beaton, R. L; Beers, T. C; Bender, C. F; Berlind, A. A; Beutler, F; Bhardwaj, V; Bird, J. C; Bizyaev, D; Blake, C. H; Blanton, M. R; Blomqvist, M; Bochanski, J. J; Bolton, A. S; Bovy, J; Bradley, A. S; Brandt, W. N; Brauer, D. E; Brinkmann, J; Brown, P. J; Brownstein, J. R; Burden, A; Burtin, E; Busca, N. G; Cai, Z; Capozzi, D; Rosell, A. C; Carr, M. A; Carrera, R; Chambers, K. C; Chaplin, W. J; Chen, Y-C; Chiappini, C; Chojnowski, S. D; Chuang, C-H; Clerc, N; Comparat, J; Covey, K; Croft, R. A. C; Cuesta, A. J; Cunha, K; da Costa, L. N; Da Rio, N; Davenport, J. R. A; Dawson, K. S; De Lee, N; Delubac, T; Deshpande, R; Dhital, S; Dutra-Ferreira, L; Dwelly, T; Ealet, A; Ebelke, G. L; Edmondson, E. M; Eisenstein, D. J; and 237 coauthors; Sivarani, T (IOP Publishing, 2015-07-20)
    The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new ...
  • Galaxy outflows without supernovae 
    Sur, Sharanya; Scannapieco, E; Ostriker, E. C (IOP Publishing, 2016-02)
    High surface density, rapidly star-forming galaxies are observed to have ≈ 50 – 100 km s − 1 line of sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from ...
  • Constraining the solar coronal magnetic field strength using split-band type ii radio burst observations 
    Kishore, P; Ramesh, R; Hariharan, K; Kathiravan, C; Gopalswamy, N (IOP Publishing, 2016-11-20)
    We report on low-frequency radio (85–35 MHz) spectral observations of four different type II radio bursts, which exhibited fundamental-harmonic emission and split-band structure. Each of the bursts was found to be closely ...
  • Observations of oppositely directed umbral wavefronts rotating in sunspots obtained from the New Solar Telescope of BBSO 
    Su, J. T; Ji, K. F; Cao, W; Banerjee, D; Priya, T. G; Zhao, J. S; Bai, X. Y; Chen, J; Zhang, M; Ji, H. S (IOP Publishing, 2016-02)
    We study the umbral waves as observed by chromospheric imaging observations of two sunspots with the New Solar Telescope at the Big Bear Solar Observatory. We find that the wavefronts (WFs) rotate clockwise and form ...
  • Can the long-term hemispheric asymmetry of solar activity result from fluctuations in dynamo parameters? 
    Nepomnyashchikh, A; Mandal, Sudip; Banerjee, D; Kitchatinov, Leonid (EDP Sciences, 2019-05)
    Context. The hemispheric asymmetry of sunspot activity observed possesses a regular component varying on a timescale of several solar cycles whose origin and properties are currently debated. Aims This paper addresses ...
  • Primordial planets predominantly of dark Matter 
    Sivaram, C; Arun, K; Kiren, O. V (Springer, 2019-05)
    Cosmic structure formation is thought to occur as a bottom-up scenario, i.e. the lightest objects would have formed first. It has been suggested that the earliest structures to form could have been primordial planets. Here ...

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