Intensity mapping of post-reionization 21-cm signal and its cross-correlations as a probe of f(R) gravity

Dash, Chandrachud B. V.; Sarkar, Tapomoy Guha; Sarkar, Arnab

doi:10.1007/s12036-022-09885-w

Cited by 3 publications

(2 citation statements)

References 116 publications

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“…For example, SKA phase I may be comparable to optical stage III experiments such as the Dark Energy Survey (Bonaldi et al 2016;Harrison et al 2016;Camera et al 2017). VLBI with SKA-Mid will also be competitive in cosmology studies, especially for ΛCDM cosmology, where autocorrelations and/or cross-correlation with galaxy weak-lensing and Lyα forest observations can be employed (e.g., Dash et al 2023). SKA-VLBI will have a higher resolution compared to SKA, making it suitable for strengthening SKA surveys, and which has great potential to bring about a major breakthrough in gravitational lensing research.…”

Section: Gravitational Lensesmentioning

confidence: 99%

VLBI with SKA: Possible Arrays and Astrometric Science

Li,

Xu,

et al. 2024

Res. Astron. Astrophys.

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The next generation of very long baseline interferometry (VLBI) is stepping into the era of microarcsecond ($\mu$as) astronomy, and pushing astronomy, especially astrometry, to new heights. VLBI with the Square Kilometre Array (SKA), SKA-VLBI, will increase current sensitivity by an order of magnitude, and reach astrometric precision routinely below 10 $\mu$as, even challenging 1 $\mu$as. This advancement allows precise parallax and proper motion measurements of various celestial objects. Such improvements can be used to study objects (including isolated objects, and binary or multiple systems) in different stellar stages (such as star formation, main-sequence stars, asymptotic giant branch stars, pulsars, black holes, white dwarfs, etc.), unveil the structure and evolution of complex systems (such as the Milky Way), benchmark the international celestial reference frame, and reveal cosmic expansion. Furthermore, the theory of general relativity can also be tested with SKA-VLBI using precise measurements of light deflection under the gravitational fields of different solar system objects and the perihelion precession of solar system objects.

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Section: Gravitational Lensesmentioning

confidence: 99%

VLBI with SKA: Possible Arrays and Astrometric Science

Li,

Xu,

et al. 2024

Res. Astron. Astrophys.

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“…[194] (see also ref. [241] for discussions on the expected sensitivity to a nCC from future 21-cm observations). From a theoretical standpoint, such a phenomenological model has been argued to loosely carry string motivation in the case where Λ < 0 [191,195,209].…”

Section: Dark Energy Modelsmentioning

confidence: 99%

Negative cosmological constant in the dark energy sector: tests from JWST photometric and spectroscopic observations of high-redshift galaxies

Menci,

Adil,

Mukhopadhyay

et al. 2024

J. Cosmol. Astropart. Phys.

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Early observations with the James Webb Space Telescope (JWST) have revealed the existence of an unexpectedly large abundance of extremely massive galaxies at redshifts z ≳ 5: these are in tension with the predictions not only of the standard ΛCDM cosmology, but also with those of a wide class of dynamical dark energy (DE) models, and are generally in better agreement with models characterized by a phantom behaviour. Here we consider a model, inspired by string theory and the ubiquity of anti-de Sitter vacua therein, featuring an evolving DE component with positive energy density on top of a negative cosmological constant, argued in an earlier exploratory analysis to potentially be able to explain the JWST observations. We perform a robust comparison of this model against JWST data, considering both photometric observations from the CEERS program, and spectroscopic observations from the FRESCO survey. We show that the model is able to accommodate the JWST observations, with a consistency probability of up to 98%, even in the presence of an evolving component with a quintessence-like behaviour (easier to accommodate theoretically compared to phantom DE), while remaining consistent with standard low-redshift probes. Our results showcase the potential of measurements of high-redshift galaxy abundances in tests of fundamental physics, and their complementarity with standard cosmological probes.

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