IIA Institutional Repository

Browsing by Subject "Dark matter"

Browsing by Subject "Dark matter"

Sort by: Order: Results:

  • Effects of dark matter in red giants 
    Clea, Sunny; Sivaram, C; Gudennavar, S. B (Elsevier B. V., 2020-12)
    Dark matter (DM) which constitutes five-sixths of all matter is hypothesized to be a weakly interacting non-baryonic particle, created in the early stages of cosmic evolution. It can affect various cosmic structures in the ...
  • Effects of dark matter in star formation 
    Arun, K; Gudennavar, S; Prasad, A; Sivaram, C (Springer, 2019-02)
    The standard model for the formation of structure assumes that there existed small fluctuations in the early universe that grew due to gravitational instability. The origins of these fluctuations are as yet unclear. In ...
  • Effects of dark matter on the upper bound mass of neutron stars 
    Kumar, S. S; Kenath, A; Sivaram, C (Elsevier B.V, 2020-05)
    Observations have indicated that we do not see neutron stars (NS) of mass near the theoretical upper limit as predicted. Here we invoke the role of dark matter (DM) particles in star formation, and their role in lowering ...
  • Enhanced star formation in the cometary globules of the GUM nebula 
    Bhatt, H. C (Royal Astronomical Society, 1993-06-01)
    Evidence for an enhanced rate of star formation in the cometary globules of the Gum nebula is presented. The IRAS Point Source Catalog has been searched for sources with spectral energy distributions characteristic of young ...
  • Evolution of primordial dark matter planets in the early Universe 
    Kiren, O. V; Arun, K; Sivarani, C (Elsevier B. V, 2021-08-15)
    In a recent paper we had discussed possibility of DM at high redshifts forming primordial planets composed entirely of DM to be oneof the reasons for not detecting DM (as the flux of ambient DM particles would be consequently ...
  • 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 ...
  • A faster growth of perturbations in an early matter dominated epoch: primordial black holes and gravitational waves 
    Das, Subinoy; Maharana, Anshuman; Muia, Francesco (Oxford University Press on behalf of Royal Astronomical Society, 2022-09)
    We present a scenario for fast growth of cosmological perturbations; δ(t) ∼ a(t)s, a(t) being the scale factor, with s > 10 for the numerical examples reported in this article. The basic ingredients of the scenario are an ...
  • 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. ...
  • Galaxy formation 
    Padmanabhan, T; Subramanian, K (Astronomical Society of India, 1992)
    An attempt is made to develop a consistent theory describing galaxy formation. First, a discussion of the smooth universe is presented. The linear theory of perturbations is introduced, and its applications are described. ...
  • 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 ...
  • Lower bounds on axion rest mass in a general cosmological scenario 
    Datta, B; Joshi, P. S (Astronomical Society of Indian, 1986-09)
    It is shown that, if axions make up the dark matter in the universe, a general lower limit range of 1.07-4.09 x 10 to the -5th eV can be set on the axion rest mass on the basis of consideration of general spacetimes, without ...
  • The M31 pixel lensing plan campaign: macho lensing and self-lensing signals 
    Novati, S. C; Bozza, V; Bruni, I; Dall'Ora, M; Paolis, F. D; Dominik, M; Gualandi, R; Ingrosso, G; Jetzer, P; Mancini, L; Nucita, A; Safonova, M; Scarpetta, G; Sereno, M; Strafella, F; Subramaniam, A; Gould, A (IOP Publishing, 2014-03-10)
    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign ...
  • Minkowski Tensors in Two Dimensions: Probing the Morphology and Isotropy of the Matter and Galaxy Density Fields 
    Appleby, S; Pravabati, C; Park, C; Hong, S. E; Kim, J; Vidhya, G (IOP Publishing, 2018-05-10)
    We apply the Minkowski tensor statistics to two-dimensional slices of the three-dimensional matter density field. The Minkowski tensors are a set of functions that are sensitive to directionally dependent signals in the ...
  • Modelling dark matter halo spin using observations and simulations: application to UGC 5288 
    Ansar, Sioree; Kataria, Sandeep Kumar; Mousumi Das (Oxford University Press on behalf of Royal Astronomical Society, 2023-06)
    Dark matter (DM) halo properties are extensively studied in cosmological simulations but are very challenging to estimate from observations. The DM halo density profile of observed galaxies is modelled using multiple ...
  • 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 ...
  • MONG: An extension to galaxy clusters 
    Rebecca, Louise; Kenath, Arun; Sivaram, C (World Scientific Publishing, 2022-04-30)
    The presence of dark matter (DM), though well established by indirect evidence, is yet to be observed directly. Various DM detection experiments running for several years have yielded no positive results. In view of these ...
  • The mystery of the cosmic diffuse ultraviolet background radiation 
    Henry, R. C; Murthy, J; Overduin, James; Tyler, Joshua (IOP Publishing Ltd, 2015-01-01)
    The diffuse cosmic background radiation in the Galaxy Evolution Explorer far-ultraviolet (FUV, 1300-1700 Å) is deduced to originate only partially in the dust-scattered radiation of FUV-emitting stars: the source of a ...
  • Near-infrared and optical imaging of Q2345+007: The largest gravitationally lensed QSO system? 
    Gopal-Krishna; Yates, M; Wiita, P. J; Smette, A; Pati, A. K; Altieri, B (The European Southern Observatory, 1993-12)
    We have taken K, R, V, and B band images of Q 2345+007, which has been claimed to be the gravitationally lensed quasar with the widest separation between the two images (approximately equal 7 arcsec), although the lens ...
  • Nonthermal warm dark matter limits from small-scale structure 
    Banerjee, Arka; Das, Subinoy; Maharana, Anshuman; Nadler, Ethan O.; Sharma, Ravi Kumar (American Physical Society, 2023-08-15)
    We present small-scale structure constraints on sterile dark matter produced from a heavy mediator particle, inspired by models of moduli decay. Dark matter particles produced through this mechanism can contribute to the ...
  • The origin of dark matter and its estimate in the metagalaxy 
    Srivastava, D. N (Astronomical Society of India, 1993)
    On dark matter, whereas current research is in the field of weakly interacting particles, this work puts forward a different line of approach. It interprets dark matter as a transformation of matter by a generalized ...

Search DSpace

Browse

My Account