Our neighboring univers

[alokmohan]

With its powerful detectors, Integral has performed the most-sensitive all-sky survey ever, finding expected clumpy areas at large scales in our local universe. Scientists working with ground-based telescopes have found the same local clumps, while looking for sources of cosmic showers. <br /><br />Integral performed the survey in the hard X-ray band of the electromagnetic spectrum. Although it wasn't the first such survey, Integral's strength lies in the fact that it is unbiased towards sources that are shrouded by dust or gas, invisible at optical and soft X-ray wavelengths. <br /><br />An interesting correlation has been found in data collected with the Auger telescopes in Argentina. Such a correlation with optical data is opening a new door in the exploration of the local universe. <br /><br />Looking around, our neighbouring local universe is fairly homogeneous. However, a lot of 'clumps' or structures are found at smaller scales, less than 100 megaparsecs or about 326 million light-years. <br /><br />Scientists believe that as the early universe expanded and grew, small perturbations introduced later formed structures confined to smaller spatial scales, leaving the universe homogeneous on scales larger than 100-200 megaparsecs (about 326 million to 652 million light-years). Integral has confirmed just this. <br /><br />The catalogue produced with the survey includes more than a hundred extragalactic objects, mainly Active Galactic Nuclei (AGNs), located at distances up to 200-300 megaparsecs (about 652 to 980 million light-years). Thanks to the hard X-ray selection, among these sources, the survey has included many dust-enshrouded AGNs. <br /><br />The survey found galaxies, clusters, superclusters, voids and even the highest known mass clumps (of mass greater than that of million of billions Suns put together) ever-observed: including the nearby Virgo cluster and the more distant Great Attractor and Perseus-Pisces supercluster. <br /><br />Nearly every galaxy in the local