186 research outputs found

    Cosmology with the largest galaxy cluster surveys: Going beyond Fisher matrix forecasts

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    We make the first detailed MCMC likelihood study of cosmological constraints that are expected from some of the largest, ongoing and proposed, cluster surveys in different wave-bands and compare the estimates to the prevalent Fisher matrix forecasts. Mock catalogs of cluster counts expected from the surveys -- eROSITA, WFXT, RCS2, DES and Planck, along with a mock dataset of follow-up mass calibrations are analyzed for this purpose. A fair agreement between MCMC and Fisher results is found only in the case of minimal models. However, for many cases, the marginalized constraints obtained from Fisher and MCMC methods can differ by factors of 30-100%. The discrepancy can be alarmingly large for a time dependent dark energy equation of state, w(a); the Fisher methods are seen to under-estimate the constraints by as much as a factor of 4--5. Typically, Fisher estimates become more and more inappropriate as we move away from LCDM, to a constant-w dark energy to varying-w dark energy cosmologies. Fisher analysis, also, predicts incorrect parameter degeneracies. From the point of mass-calibration uncertainties, a high value of unknown scatter about the mean mass-observable relation, and its redshift dependence, is seen to have large degeneracies with the cosmological parameters sigma_8 and w(a) and can degrade the cosmological constraints considerably. We find that the addition of mass-calibrated cluster datasets can improve dark energy and sigma_8 constraints by factors of 2--3 from what can be obtained compared to CMB+SNe+BAO only. Since, details of future cluster surveys are still being planned, we emphasize that optimal survey design must be done using MCMC analysis rather than Fisher forecasting. [abridged]Comment: 26 pages, 13 figures, 7 tables, accepted for publication in JCA

    Precision cosmology with a combination of wide and deep Sunyaev-Zeldovich cluster surveys

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    We show the advantages of a wedding cake design for Sunyaev-Zel'dovich cluster surveys. We show that by dividing up a cluster survey into a wide and a deep survey, one can essentially recover the cosmological information that would be diluted in a single survey of the same duration due to the uncertainties in our understanding of cluster physics. The parameter degeneracy directions of the deep and wide surveys are slightly different, and combining them breaks these degeneracies effectively. A variable depth survey with a few thousand clusters is as effective at constraining cosmological parameters as a single depth survey with a much larger cluster sample.Comment: 4 figures, 1 table; revised versio

    Kupipakwa Rasayana: Unique Metalo-Mineral preparation

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    Kupipakwa Rasayana is used as therapeutic agents in the Indian system of Medicine, Ayurveda. It is unique due to its method of preparation. Kupipakwa Rasayana are prepared in the specially designed device Valuka Yantra. Parada (Mercury) and Gandhaka (Sulphur) are the chief ingredients in this medicine along with other metals and minerals. These Kupipakwa Rasayana are used in the different disorders like Rajyakshma, Kushtha, Prameha, Arsha, Vatvikara etc. Here in the present study it was decided to screen and review its reported experimental efficacy studies. On screening, it was revealed that numerous Kupipakwa Rasayana showed significant anti-microbial, anti-diabetic, anti-oxidant, immune-modulatory, anti-hyperglycemic properties. The observed encouraging results shows the further scope for broad spectrum research era in Kupipakwa Rasayana

    Scattering of emission lines in galaxy cluster cores: measuring electron temperature

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    The central galaxies of some clusters can be strong emitters in the Lyα\alpha and Hα\alpha lines. This emission may arise either from the cool/warm gas located in the cool core of the cluster or from the bright AGN within the central galaxy. The luminosities of such lines can be as high as 1042−104410^{42} - 10^{44} erg/s. This emission originating from the core of the cluster will get Thomson scattered by hot electrons of the intra-cluster medium (ICM) with an optical depth ∼\sim 0.01 giving rise to very broad (Δλ/λ∼\Delta \lambda / \lambda \sim 15%) features in the scattered spectrum. We discuss the possibility of measuring the electron density and temperature using information on the flux and width of the highly broadened line features.Comment: 9 pages, 5 figures, accepted in MNRA

    An Efficient Authenticating Short Encrypted Messages Using IND-CPA Algorithms

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    In today's age of information and technology , many applications can exchange network of information and communication. In Banking , educational, economical area can also exchange the information over the internet. The exchange of information is too risky to work from internet. So many hackers are try to stolen information from the internet. So there is must require data security and integrity over the internet.There are many authentication Technics are in information technology fields. Like HMAC , UMAC, etc.but all this authentication schemes are time consuming and less secure .so we propose more secure and less time consuming authentication codes that are more useful than any other message authentication code in the our literature survey . DOI: 10.17762/ijritcc2321-8169.15073

    On Cohomology theory for topological groups

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    We construct some new cohomology theories for topological groups and Lie groups and study some of its basic properties. For example, we introduce a cohomology theory based on measurable cochains which are continuous in a neighbourhood of identity. We show that if G and A are locally compact and second countable, then the second cohomology group based on locally continuous measurable cochains as above parametrizes the collection of locally split extensions of G by A

    Some interesting morphological features of liver lobes in Mumbai population

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    Introduction: Liver is the largest gland in the body mainly situated in the right upper quadrant of the abdomen. Abnormalities of liver are rare. Common abnormalities are irregularities in form, occurrence of one or more accessory lobes, fissures or abnormal ligaments. Rare abnormalities include atrophy, or complete absence of one of the lobes. Although the segmental anatomy of the liver has been extensively researched, very few studies have dealt with the surface variations of the liver. Accessory lobe may be confused with tumour. Accessory fissure may mimic internal trauma at the time of the post-mortem study. Aim: Present study was carried to find out the morphological variations of liver lobes occurring in Mumbai population. Methods & Materials: The materials used for present study comprised of formalin fixed 50 adult livers. Results & conclusion: In the present study we found accessory liver lobes in 3 cadavers i.e. 6 %, atrophy of left lobe in 15 cadavers i.e. 30 %, accessory fissures in 21 cases i.e.42%.There is also abnormal connection between left lobe and quadrate lobe in 14% cases. The findings of study may be helpful to radiologist and surgeons respectively, to avoid possible errors in interpretations and subsequent misdiagnosis, and for planning appropriate surgical approaches
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