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Browsing IIAP Publications by Subject "Cosmology"

Browsing IIAP Publications by Subject "Cosmology"

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  • The afterglow and the host galaxy of GRB 011211 
    Jakobsson, P; Hjorth, J; Fynbo, J. P. U; Gorosabel, J; Pedersen, K; Burud, I; Levan, A; Kouveliotou, C; Tanvir, N; Fruchter, A; Rhoads, J; Grav, T; Hansen, M. W; Michelsen, R; Jensen, B. L; Pedersen, H; Thomsen, B; Weidinger, M; Bhargavi, S. G; Cowsik, R; Pandey, S. B (The European Southern Observatory, 2003-09)
    We present optical, near-infrared, and X-ray observations of the optical afterglow (OA) of the X-ray rich, long-duration gamma-ray burst GRB 011211. Hubble Space Telescope (HST) data obtained 14, 26, 32, and 59 days after ...
  • The angular appearance of white holes 
    Narlikar, J. V; Kapoor, R. C (D. Reidel Publishing Company, 1978-01)
    It is shown that non-radial light rays emitted from the surface of a white hole can emerge from inside the Schwarzschild barrier. The upper limit on their impact parameter is calculated under the requirement that such rays ...
  • Anomalous redshifts of quasi-stellar objects 
    Narlikar, J. V; Das, P. K (American Astronomical Society, 1980-09)
    This paper is based on the assumption that the observational evidence to date does point to the possibility that high-redshift quasars are physically associated with low-redshift galaxies. It is first argued that the excess ...
  • Application of the contour Minkowski tensor and D statistic to the Planck E -mode data 
    Joby, P. K; Sen, Aparajita; Ghosh, Tuhin; Pravabati, C; Basak, Soumen (American Physical Society, 2021-06-15)
    We test the statistical isotropy (SI) of the E -mode polarization of the cosmic microwave background (CMB) radiation observed by the Planck satellite using two statistics, namely, the α estimator that is derived ...
  • Atomic electric-dipole moments from Higgs-boson-mediated interactions 
    Sahoo, B. K; Das, B. P; Chaudhuri, R. K; Mukherjee, D; Venugopal, E. P (The American Physical Society, 2008-07)
    Electric-dipole moments of paramagnetic atoms can provide important insights into a unique kind of CP violation involving Higgs-boson-mediated interactions between leptons and hadrons. We report a limit for the coupling ...
  • Clustering of galaxies by inverse cascade in a turbulent medium 
    Krishan, V; Sivaram, C (Royal Astronomical Society, 1991-05)
    A definite physical mechanism based in inverse cascading is suggested which quite naturally yields a bottom-up hierarchical structure for galactic clustering. In this mechanism, nonlinear interactions between small fluid ...
  • The completed SDSS-IV extended baryon oscillation spectroscopic survey: BAO and RSD measurements from the anisotropic power spectrum of the quasar sample between redshift 0.8 and 2.2 
    Neveux, Richard; Burtin, Etienne; Mattia, Arnaud de; Smith, Alex; Ross, Ashley J; Hou, Jiamin; Bautista, Julian; Brinkmann, Jonathan; Chuang, Chia-Hsun; Dawson, Kyle S; Gil-Marin, Hector; Lyke, Brad W; Macorra, Axel de la; Bourboux, Helion du Mas des; Mohammad, Faizan G; Muller, Eva-Maria; Myers, Adam D; Newman, Jeffrey A; Percival, Will J; Rossi, Graziano; Schneider, Donald; Vivek, M; Zarrouk, Pauline; Zhao, Cheng; Zhao, Gong-Bo (Oxford University Press on behalf of the Royal Astronomical Society, 2020-11)
    We measure the clustering of quasars of the final data release (DR16) of eBOSS. The sample contains 343708 quasars between redshifts 0.8 ≤ z ≤ 2.2 over 4699deg2⁠. We calculate the Legendre multipoles (0,2,4) of the anisotropic ...
  • The Completed SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations with Lyα Forests 
    du Mas des Bourboux, H; Rich, J; Font-Ribera, A; de Sainte Agathe, V; Farr, J; Etourneau, T; Le Goff, J.-M; Cuceu, Andrei; Balland, C; Bautista, J. E; Blomqvist, M; Brinkmann, J; Brownstein, J. R; Chabanier, S; Chaussidon, E; Dawson, K; Gonzalez-Morales, A. X; Guy, J; Lyke, B. W; de la Macorra, A; Mueller, E.-M; Myers, A. D; Nitschelm, C; Gutierrez, A. M; Palanque-Delabrouille, N; Parker, J; Percival, W. J; Perez-Rafols, I; Petitjean, P; Pieri, M. M; Ravoux, R; Rossi, R; Schneider, D. P; Seo, H.-J; Slosar, A; Stermer, J; Vivek, M; Yeche, C; Youles, S (IOP Publishing, 2020-10-01)
    We present a measurement of baryonic acoustic oscillations (BAOs) from Lyα absorption and quasars at an effective redshift z = 2.33 using the complete extended Baryonic Oscillation Spectroscopic Survey (eBOSS). The 16th ...
  • Cosmic background temperature and the coupling constants of fundamental interactions 
    Sivaram, C (Kluwer Academic Publishers, 1993-08)
    The underlying links between the coupling constants of the fundamental interactions and cosmological parameters explored earlier is shown to give rise to a definite value for the cosmic background temperature.
  • Cosmic perspectives : essays dedicated to the memory of M.K.V. Bappu 
    Biswas, S. K (editor); Mallik, D. C. V (editor); Vishveshwara, C. V (editor) (Cambridge University Press, 1989)
    Cosmic Perspectives is a collection of essays that details modern cosmology and its relationship to the development of human civilization. Written by leading astronomers, cosmologists and historians, these fourteen essays ...
  • Cosmoglobe: Towards end-to-end CMB cosmological parameter estimation without likelihood approximations 
    Eskilt, J. R; Lee, K; Watts, D. J; Anshu, V; Aurlien, R; Basyrov, A; Bersanelli, M; Colombo, L. P. L; Eriksen, H. K; Fornazier, K. S. F; Fuskeland, U; Galloway, M; Gjerlow, E; Hergt, L. T; Ihle, H. T; Lunde, J. G. S; Marins, A; Nerval, S. K; Paradiso, S; Rahman, Fazlu; San, M; Stutzer, N. O; Wehus, I. K (EDP Sciences, 2023-10)
    We implement support for a cosmological parameter estimation algorithm in Commander and quantify its computational efficiency and cost. For a semi-realistic simulation similar to Planck LFI 70 GHz, we find that the ...
  • The cosmological constant as a unifying link 
    Sivaram, C (Anita Publications, 2005)
  • A cosmological prediction from the coupling constants of fundamental interactions 
    Sivaram, C (Springer, 1986-07)
    The notion of gravitational charge is used to suggest a link in the Machian sense between fundamental interactions and cosmology. The observed values of the coupling constants of these interactions then give a definite ...
  • Deep J -band imaging of high redshift QSO candidates with the Himalayan Chandra Telescope 
    Goto, T; Ojha, D (Astronomical Society of India, 2006)
    High redshift QSOs (redshift >5.7) are highly important ob jects. If such QSOs may be found, their spectra will reveal the onset of reionization of the intergalactic medium (Gunn-Peterson trough), and provide precious in ...
  • Ensemble Average of Three-dimensional Minkowski Tensors of a Gaussian Random Field in Redshift Space 
    Appleby, S; Joby, P. K; Pravabati, C; Park, C (IOP Publishing, 2019-11-20)
    We present the ensemble expectation values for the translation-invariant, rank-2 Minkowski tensors in three dimensions, for a linearly redshift-space-distorted Gaussian random field. The Minkowski tensors W1 0,2, W2 0,2 ...
  • Ether, Luminosity and Galactic Source Counts 
    Tomaschitz, R (Kluwer Academic Publishers, 1998-08)
    An interpretation of the cosmological redshift in terms of a cosmic ether is given. We study a Robertson-Walker cosmology in which the ether is phenomenologically defined by a homogeneous and isotropic permeability tensor. ...
  • A feasibility study of cosmic microwave radiation via graphite needles 
    Sivaram, C; Shah, G. A (D. Reidel Publishing Co.,, 1985-12)
    It is pointed out that the total amount of microwave radiation that could possibly be generated by all the graphite needles in space would be considerably smaller than the observed total energy of the cosmic microwave ...
  • Formation and Abundance of Late-forming Primordial Black Holes as Dark Matter 
    Chakraborty, Amlan; Chanda, Prolay K; Pandey, Kanhaiya L; Das, Subinoy (American Astronomical Society, 2022-06-20)
    We propose a novel mechanism where primordial black hole (PBH) dark matter is formed much later in the history of the universe, between the epochs of Big Bang nucleosynthesis and cosmic microwave background photon decoupling. ...
  • Fundamental interactions in the early universe 
    Sivaram, C (Springer, 1994-05)
    A unified approach to fundamental interactions as explored earlier is further elaborated and its consequences for the early universe studied especially in connection with the energy dependence of the coupling constants.
  • Hundred Years of Einstein's Cosmological Constant 
    Sivaram, C; Arun, K; Kiren, O. V; Sivaram, C (Isaac Scientific Publishing, 2018-06)
    It was little over a hundred years ago that Einstein introduced the ‘cosmological constant’ in his General Theory of Relativity in order to obtain a static universe, to conform to the philosophical view of the universe ...

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