Browsing Institutt for teoretisk astrofysikk by Author "Mota, David"
Now showing items 61-80 of 81
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Asghari, Mahnaz; Beltran Jimenez, Jose; Khosravi, Shahram; Mota, David (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)We consider a cosmological model with an interaction between dark matter and dark energy which leaves the background cosmology unaffected and only affects the evolution of the perturbations. This is achieved by introducing ...
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Ho, Alex; Gronke, Max Balthasar; Falck, Bridget Lynn; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)Multiple modifications of general relativity (GR) have been proposed in the literature in order to understand the nature of the accelerated expansion of the Universe. However, thus far all the predictions of GR have been ...
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Hammami, Amir; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)Reproduced with permission from Astronomy & Astrophysics, © ESO 2017
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Llinares, Claudio; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)Several extensions of general relativity and high energy physics include scalar fields as extra degrees of freedom. In the search for predictions in the nonlinear regime of cosmological evolution, the community makes use ...
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Sahlu, Shambel; Ntahompagaze, Joseph; Abebe, Amare; de la Cruz Dombriz, Álvaro; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
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Mina, Mattia; Mota, David; Winther, Hans Arnold (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)We present a new code,SCALAR, based on the high-resolution hydrodynamics andN-body codeRAMSES, to solve the Schrödingerequation on adaptive refined meshes. The code is intended to be used to simulate axion ...
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Vargas dos santos, Marcelo; Alcaniz, Jailson S; Mota, David; Capozziello, Salvatore (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)We investigate the efficiency of screening mechanisms in the hybrid metric-Palatini gravity. The value of the field is computed around spherical bodies embedded in a background of constant density. We find a thin shell ...
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Koivisto, Tomi Sebastian; Mota, David; Zumalacárregui, Miguel (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)It is shown that extensions to general relativity, which introduce a strongly coupled scalar field, can be viable if the interaction has a nonconformal form. Such disformal coupling depends upon the gradients of the scalar ...
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Aviles, Alejandro; Cervantes-Cota, Jorge L; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)We present a formalism to study screening mechanisms in modified theories of gravity through perturbative methods in different cosmological scenarios. We consider Einstein-frame posed theories that are recast as Jordan-frame ...
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Llinares, Claudio; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)Scalar fields are crucial components in high energy physics and extensions of general relativity. The fact that they are not observed in the Solar System may be due to a mechanism which screens their presence in high dense ...
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Mina, Mattia; Mota, David; Winther, Hans Arnold (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)We present the results of a full cosmological simulation with the new code SCALAR , where dark matter is in the form of fuzzy dark matter (FDM), described by a light scalar field with a mass of m B = 2.5 × 10 −22 eV and ...
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Silva, M. F.; Winther, Hans Arnold; Mota, David; Martins, Carlos Jose Amaro Parente (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)We investigate the variation of the fine-structure constant, α, in symmetron models using N-body simulations in which the full spatial distribution of α at different redshifts has been calculated. In particular, we obtain ...
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Sapa, Stharporn; Karwan, Khamphee; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)We investigate the effects of a disformal coupling between dark energy and dark matter in the predictions of the spherical collapse and its signatures in galaxy cluster number counts. We find that the disformal coupling ...
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Davis, A.-C.; Li, Baojiu; Mota, David; Winther, Hans Arnold (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)Scalar fields, strongly coupled to matter, can be present in nature and still be invisible to local experiments if they are subject to a screening mechanism. The symmetron is one such mechanism that relies on restoration ...
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Honardoost, M.; Mota, David; Sepangi, H. R. (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)We investigate the compatibility of the Symmetron with dark energy by introducing a non-minimal kinetic term associated with the Symmetron. In this new model, the effect of the friction term appearing in the equation of ...
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Mota, David; Salzano, Vincenzo; Capozziello, S. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2011)We investigate whether there is any cosmological evidence for a scalar field with a mass and coupling to matter which change accordingly to the properties of the astrophysical system it “lives in,” without directly focusing ...
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Hagala, Robert; Llinares, Claudio; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)Context: There are currently no reliable methods to measure the transverse velocities of galaxies. This is an important piece of information that is lacking in galaxy catalogues, and it could allow us to probe the physics ...
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Mauland-Hus, Renate; Elgarøy, Øystein; Mota, David; Winther, Hans Arnold (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)Massive neutrinos and f ( R )-modified gravity have degenerate observational signatures that can impact the interpretation of results in galaxy survey experiments, such as cosmological parameter estimations and gravity ...
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Del Popolo, Antonino; Chan, Man Ho; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)We determine the relationship between the turnaround radius, Rt, and mass, Mt, in Λ CDM , and in dark energy scenarios, using an extended spherical collapse model taking into account the effects of shear and vorticity. We ...
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Salzano, Vincenzo; Mota, David; Capoziello, S.; Napolitano, N. R. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)Aims: We investigated the gravitational effects of a scalar field within scalar-tensor gravity as an alternative to dark matter. Motivated by chameleon, symmetron, and f(R)-gravity models, we studied a phenomenological ...