IIA Institutional Repository

Browsing IIAP Publications by Subject "Dark energy"

Browsing IIAP Publications by Subject "Dark energy"

Sort by: Order: Results:

  • Alternate Models to Dark Energy 
    Arun, K; Gudennavar, S. B; Prasad, A; Sivaram, C (Elsevier B.V, 2018-01)
    One of the unresolved questions currently in cosmology is that of the non-linear accelerated expansion of the universe. This has been attributed to the so called Dark Energy (DE). The accelerated expansion of the universe ...
  • 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 ...
  • 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 ...
  • Dark matter (energy) may be indistinguishable from modified gravity (MOND) 
    Sivaram, C (World Scientific Publishing Co Pte Ltd, 2017-10)
    For Newtonian dynamics to hold over galactic scales, large amounts of dark matter (DM) are required which would dominate cosmic structures. Accounting for the strong obser- vational evidence that the universe is accelerating ...
  • Dark matter density distributions and dark energy constraints on structure formation including MOND 
    Rebecca, L; Arun, K; Sivaram, C (Springer, 2020-09)
    In recent papers, it was shown explicitly that the sizes of gravitationally bound large-scale cosmic structures can be constrained from the requirement that their gravitational binding self-energy density should at least ...
  • Dark matter, dark energy, and alternate models: A review 
    Arun, k; Gudennavar, S.B; Sivaram, C (Elsevier B.V, 2017-07)
    The nature of dark matter (DM) and dark energy (DE) which is supposed to constitute about 95% of the energy density of the uni-verse is still a mystery. There is no shortage of ideas regarding the nature of both. While ...
  • Early mass-varying neutrino dark energy: nugget formation and Hubble anomaly 
    Gogoi, Antareep; Sharma, Ravi Kumar; Chanda, Prolay; Das, Subinoy (IOP Publishing, 2021-07-10)
    We present a novel scenario in which light (~few eV) dark fermions (sterile neutrinos) interact with a scalar field as in mass-varying neutrino dark energy theories. As the eV sterile states naturally become nonrelativistic ...
  • Extended Equivalence Principle: Implications for Gravity, Geometry and Thermodynamics 
    Sivaram, C; Arun, K (Handronic Press Inc, 2012)
    The equivalence principle was formulated by Einstein in an attempt to extend the concept of inertial frames to accelerated frames. Thereby bringing in gravity. In recent decades, it has been realized that gravity is linked ...
  • Extremal charged black holes, dark matter and dark energy 
    Sivaram, C; Arun, K; Prasad, A (Springer, 2018-10)
    Formation of black holes may be constrained by intrinsic parameters characterizing them such as electric charge. Here we discuss the effects of a relatively minute excess of charge on extremal black hole formation and the ...
  • The Hubble tension: change in dark energy or a case for modified gravity? 
    Sivaram, C; Arun, K; Rebecca, Louise (Springer, 2022-03)
    Recently, much controversy has been raised about the cosmological conundrum involving the discrepancy in the value of the Hubble constant as implied by Planck satellite observations of the CMBR in the early Universe and ...
  • 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 ...
  • Implications of an Extended Dark Energy Model with Massive Neutrinos 
    Sharma, Ravi Kumar; Pandey, Kanhaiya L; Das, Subinoy (American Astronomical Society, 2022-08-01)
    Recently there have been reports of finding a lower bound on the neutrino mass parameter (Σmν) when using the Atacama Cosmology Telescope (ACT) and SPTpol data; however, these bounds on the Σmν are still weaker for most ...
  • MOND, MONG, MORG as alternatives to dark matter and dark energy, and consequences for cosmic structures 
    Sivaram, C; Arun, Kenath; Rebecca, Louise (Indian Academy of Sciences, 2020-02)
    In view of the negative results from various dark matter detection experiments, we propose alternate models by postulating a minimal field strength (minimal curvature) and also a minimal acceleration. These postulates ...
  • Planckian pre big bang phase of the Universe 
    Sivaram, C; Arun, K; Rebecca, L (Springer, 2020-01)
    The standard model of cosmology, although very successful, has problems with the very initial phase, such as the existence of a singularity when the density and curvature becomes infinite. In this work we propose a possible ...

Search DSpace


Browse

My Account