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Cosmology

About: Cosmology is a research topic. Over the lifetime, 18004 publications have been published within this topic receiving 631028 citations. The topic is also known as: physical cosmology & cosmologies.


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Proceedings ArticleDOI
01 Aug 1997

206 citations

Journal ArticleDOI
02 Dec 2011-Science
TL;DR: The detection of deuterium in one system at the level predicted by primordial nucleosynthesis provides a direct confirmation of the standard cosmological model and implies that the transport of heavy elements from galaxies to their surroundings is highly inhomogeneous.
Abstract: In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced later in stars. To date, however, heavy elements have been observed in all astrophysical environments. We report the detection of two gas clouds with no discernible elements heavier than hydrogen. These systems exhibit the lowest heavy-element abundance in the early universe, and thus are potential fuel for the most metal-poor halo stars. The detection of deuterium in one system at the level predicted by primordial nucleosynthesis provides a direct confirmation of the standard cosmological model. The composition of these clouds further implies that the transport of heavy elements from galaxies to their surroundings is highly inhomogeneous.

206 citations

Journal ArticleDOI
17 Feb 2000-Nature
TL;DR: During the lifetime of their Milky Way galaxy, there have been something like 100 million supernova explosions, which have enriched the Galaxy with the oxygen the authors breathe, the iron in their cars, the calcium in their bones and the silicon in the rocks beneath their feet.
Abstract: During the lifetime of our Milky Way galaxy, there have been something like 100 million supernova explosions, which have enriched the Galaxy with the oxygen we breathe, the iron in our cars, the calcium in our bones and the silicon in the rocks beneath our feet. These exploding stars also influence the birth of new stars and are the source of the energetic cosmic rays that irradiate us on the Earth. The prodigious amount of energy (approximately 10(51), or approximately 2.5 x 10(28) megatonnes of TNT equivalent) and momentum associated with each supernova may even have helped to shape galaxies as they formed in the early Universe. Supernovae are now being used to measure the geometry of the Universe, and have recently been implicated in the decades-old mystery of the origin of the gamma-ray bursts. Together with major conceptual advances in our theoretical understanding of supernovae, these developments have made supernovae the centre of attention in astrophysics.

206 citations

Journal ArticleDOI
TL;DR: In this paper, cosmological constraints on scenarios in which the gravitino is the lightest supersymmetric particle and a charged slepton is the next-to-lightest super-symmetric particle (NLSP) were studied.
Abstract: The gravitino is a promising cold dark matter candidate. We study cosmological constraints on scenarios in which the gravitino is the lightest supersymmetric particle and a charged slepton the next-to-lightest supersymmetric particle (NLSP). We obtain new results for the hadronic nucleosynthesis bounds by computing the four-body decay of the NLSP slepton into the gravitino, the associated lepton, and a quark–antiquark pair. The bounds from the observed dark matter density are refined by taking into account gravitinos from both late NLSP decays and thermal scattering in the early Universe. We examine the present free-streaming velocity of gravitino dark matter and the limits from observations and simulations of cosmic structures. Assuming that the NLSP sleptons freeze out with a thermal abundance before their decay, we derive new bounds on the slepton and gravitino masses. The implications of the constraints for cosmology and collider phenomenology are discussed and the potential insights from future experiments are outlined. We propose a set of benchmark scenarios with gravitino dark matter and long-lived charged NLSP sleptons and describe prospects for the Large Hadron Collider and the International Linear Collider.

205 citations

Journal ArticleDOI
TL;DR: In this paper, the search for the curl component (B mode) in the cosmic microwave background (CMB) polarization induced by inflationary gravitational waves is described, and issues involved in the experimental pursuit of these B modes are described.
Abstract: The search for the curl component (B mode) in the cosmic microwave background (CMB) polarization induced by inflationary gravitational waves is described. The canonical single-field slow-roll model of inflation is presented, and we explain the quantum production of primordial density perturbations and gravitational waves. It is shown how these gravitational waves then give rise to polarization in the CMB. We then describe the geometric decomposition of the CMB polarization pattern into a curl-free component (E mode) and curl component (B mode) and show explicitly that gravitational waves induce B modes. We discuss the B modes induced by gravitational lensing and by Galactic foregrounds and show how both are distinguished from those induced by inflationary gravitational waves. Issues involved in the experimental pursuit of these B modes are described, and we summarize some of the strategies being pursued. We close with a brief discussion of some other avenues toward detecting/characterizing the inflationar...

205 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023768
20221,518
2021737
2020784
2019782