Formation of a new superconducting tetragonal phase, YBCO-T* (T c = 87 K) in YBa2Cu3O7??

Subramanian, S.; Swamy, C. S.; Karge, Hellmut G.

doi:10.1007/bf00455622

Cited by 8 publications

(13 citation statements)

References 15 publications

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“…-The gas density of collapsed baryons in systems with rotation speed of > 180 km/s, as a function of redshift for six models. The observations are from Lanzetta et al (1995) and Storrie-Lombardi et al 91996) with 1σ errorbars.the conclusion drawn byMa et al (1997) for a comparable model, and consistent with previous analyses(Subramanian & Padmanabhan 1994; Kauffmann & Charlot 1994;Mo & Miralda-Escudé 1994; …”

supporting

confidence: 85%

Testing Cold Dark Matter Models at Moderate to High Redshift

Cen

1998

ApJ

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The COBE microwave background temperature fluctuations and the abundance of local rich clusters of galaxies provide the two most powerful constraints on cosmological models. When all variants of the standard cold dark matter (CDM) model are subject to the combined constraint, the power spectrum of any model is fixed to ∼ 10% accuracy in both the shape and overall amplitude. These constrained models are not expected to differ dramatically in their local large-scale structure properties. However, their evolutionary histories differ, resulting in dramatic differences towards high redshift. In particular, it should be true that any statistical measure that probes a rapidly diminishing tail of some distribution should provide a sensitive test at some sufficiently high redshift, when the objects in question are rare and hence in the tail.We examine in detail six standardized, COBE and cluster normalized CDM models with respect to a large set of independent observations. The observations include correlation function of rich clusters of galaxies, galaxy power spectrum, evolution of rich cluster abundance, gravitational lensing by moderateto-high redshift clusters, Lyα forest, damped Lyα systems, high redshift galaxies, reionization of the universe and future CMB experiments. It seems that each of the independent observations examined is or potentially is capable of distinguishing between at least some of the models. The combined power of several or all of these observations is tremendous. Thus, we appear to be on the verge of being able to make dramatic tests of all models in the near future using a rapidly growing set of observations, mostly at moderate to high redshift. Consistency or inconsistency between different observed phenomena on different scales and/or at different epochs with respect to the models will have profound implications for theory of growth of cosmic structure.

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supporting

confidence: 85%

Testing Cold Dark Matter Models at Moderate to High Redshift

Cen

1998

ApJ

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“…Several authors (Subramanian & Padmanabhan 1994;Mo & Miralda-Escudé 1994;Kauffmann & Charlot 1994;Ma & Bertschinger 1994) have recently claimed that the large value of Ωg observed at z ∼ > 3 is incompatible with predictions of the Mixed (i.e. cold+hot) Dark Matter (MDM) model with spectral index n = 1 and Ων ≃ 0.3 contributed by one species of massive neutrinos and Ω b = 0.1 for the baryon fractional density Nolthenius, Klypin & Primack 1995).…”

Section: Introductionmentioning

confidence: 99%

The epoch of structure formation in blue mixed dark matter models

Borgani¹,

Lucchin²,

Matarrese³

et al. 1996

Monthly Notices of the Royal Astronomical Society

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Recent data on the high-redshift abundance of damped Lyα systems are compared with theoretical predictions for 'blue' (i.e. n > 1) Mixed Dark Matter models. The results show that decreasing the hot component fraction Ω ν and/or increasing the primordial spectral index n implies an earlier epoch of cosmic structure formation. However, we also show that varying Ω ν and n in these directions makes the models barely consistent with the observed abundance of galaxy clusters. Therefore, requiring at the same time observational constraints on damped Lyα systems and cluster abundance to be satisfied represents a challenge for the Mixed Dark Matter class of models.

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“…Several authors recognized DLAS as a powerful test for DM models, based on a linear theory approach, Subramanian & Padmanabhan (1994), Kauffman & Charlot (1994), Mo & Miralda-Escudé (1994) and Ma & Bertschinger (1994) concluded that the standard CHDM scenario with Ω ν = 0.3 is not able to generate enough collapsed structures at z ∼ > 3, due to the lack of power on galactic scales. However, either lowering Ω ν to about 0.2 or 'blueing' the primordial spectrum, P i (k) ∝ k n to n ≃ 1.2 keeps CHDM into a better agreement with data.…”

Section: High-redshift Behaviourmentioning

confidence: 99%

Large-Scale Structure in Mixed Dark Matter Models with a Nonthermal Volatile Component

Pierpaoli¹,

Coles²,

Bonometto³

et al. 1996

ApJ

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We investigate the properties of large-scale structure predicted in a class of mixed dark matter models in which the volatile component (made of particles with high rms velocity) derives from the decay of a heavier particle. Such models based on cold+volatile dark matter (CVDM) differ from the standard mixture of CDM and massive neutrinos, usually known as CHDM, in that they involve a component which has a non-thermal phase space distribution function. As a consequence, and differently from CHDM models, the value of the redshift at which volatile particles become non relativistic, z nr , can be varied almost independently of the volatile fraction, Ω X . We compute transfer functions for a selection of such models, having 0.1 ≤ Ω X ≤ 0.5 and different values of z nr . Using linear theory and assuming a scalefree primordial spectrum, we compare such models with observational constraints on largescale galaxy clustering and bulk flows, as well as on the abundance of galaxy clusters and high-redshift damped Lyα systems. We find that these constraints enable us to discriminate between different Ω X and z nr ; within the range of the models inspected, those which can be most easily accommodated by the data correspond to the parameter choice Ω X ≃ 0.2 and z nr ≃ 2 × 10 4 Ω X .Subject headings: Cosmology: large-scale structure of the universe -galaxies: clusters: general 1

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Formation of a new superconducting tetragonal phase, YBCO-T* (T c = 87 K) in YBa2Cu3O7??

Cited by 8 publications

References 15 publications

Testing Cold Dark Matter Models at Moderate to High Redshift

Testing Cold Dark Matter Models at Moderate to High Redshift

The epoch of structure formation in blue mixed dark matter models

Large-Scale Structure in Mixed Dark Matter Models with a Nonthermal Volatile Component

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