*Mr. Rupak Bhattacharya-Bsc(cal), Msc(JU), of residences 7/51Purbapalli, Sodepur, Dist 24 Parganas(north) Kol-110,West Bengal, India**ProfessorPranab kumar Bhattacharya- MD(cal), FIC Path(Ind), Professor and HOD of Pathology convener in-charge of DCP and DLT course of WBUHS, , Calcutta school of Tropical Medicine, 108, CR Avenue, KOlkata-73 , West Bengal, India, Ex- Professor and HOD Ophthalmic pathology, RIO KOl-73, Ex professor of Pathology WBUHS and EX Add. Professor IPGME&R KOl-20 W.B, India** Miss Upasana Bhattacharya – only daughter of Professor Pranab Kumar Bhattacharya of mahamaya Apartment Mahamyatala, Garia kol-84 *Mr.RitwikBhattacharya B.com(cal), *Miss Rupsa Bhattacharya-,* Mr Soumyak Bhattacharya BHM(cal) MSC(student) PUSHA, New Delhi, all of residence 7/51 Purbapalli, Sodepur, Dist 24 parganas(north) ,Kolkata-110,WestBengal, India*** Mrs. Dalia Mukherjee BA(hons) Cal, Swamiji Road, South Habra, 24 Parganas(north) West Bengal, India*** Mrs Dalia Mukherjee BA(hons) Cal cutta university, ***Miss Oaindrila Mukherjee- BA(hons) Student Cal Univ, ***Mr Debasis Mukherjee BSC(cal) ,Swamiji Road, South Habra, 24 Parganas(north), West Bengal, India
Quasars are the most distant distinct objects that astronomers have been able to detect. In a region smaller than our solar system, a quasar in fact emits more & more light than our total entire Milky Way galaxy emits light. Can you imagine that ? But Quasars are again believed to be super massive black holes, whose masses exceed that of a million Suns, and whose pull is swallowing gas and stars from their host galaxies. Then black holes also emits light. They do shine brightly by converting the gravitational energy of the in falling Astronomers and physicists are not till date certain what objects ionized the gas(Mixed dark matter oe WIMP) in the early universe nor do they know at what time this ionization occurred. Some speculate that an early generation of massive stars ionized the gas. Others speculate that most galaxies contain super massive black holes and that the formation of these super massive black holes illuminated the early universe. When Was then Gas Ionized is our question ? While observations of quasars enable astronomers to infer that the gas was ionized within the first billion years of the universe, we need to observe something more distant than quasars to learn when the gas was first ionized: the cosmic microwave background radiation. Since the cosmic microwave background photons were emitted roughly 380,000 years after the Big Bang, much earlier than the photons from quasars, their properties tell us about the subsequent evolutionary history of the universe. Microwave photons move freely through neutral gas, but they scatter off of ionized gas. This scattering reduces the amplitude of fluctuations in the temperature of the cosmic microwave background and produces new "polarized" microwave background fluctuations.material into light. The most distant quasars are seen at a time when the universe was one tenth its present age, roughly a billion years after the Big Bang
What Ionized the Gas in the Early Universe? Scattered light is often polarized. On a bright day, we see not only sunlight directly from the Sun, but also light that scatters off of dust in the air. This scattered light, or "glare", is polarized and can thus be filtered out by a good pair of polarized sunglasses. Similarly, scattered cosmic microwave background photons are polarized by scattering off of free electrons in the early universe. WMAP is designed to detect polarized photons. In principal, their properties reveal the number of free electrons in the early universe and the ionization history of the universe. This enables astronomers to infer that the first objects in the universe capable of ionizing the gas formed at about 200 million years after the Big Bang. We hope that the time history of the ionization will help determine the nature of these first objects
How the spiral galaxies were formed? Before formation of the galaxies, there were pre galactic clouds which is consisted of gaseous substance. Sir James Jeans first proposed that when the same density perturbation exist in the homogenous gas clouds and when clouds exceeds a certain limit, the cloud suffer an instability. As a result the cloud begins to collapse. The Jeans critical mass (Mj) was described as follows.
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