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Sunday, 31 March 2013

The First Generation of Stars formation at Red shift Z-0 and when did they lit up from the dark Matter

http://www.sciencenews.org/view/generic/id/48016/description/
Authors_;

* Mr. Rupak Bhattacharya-Bsc(cal)Msc(JU) of Residence 7/51 purbapalli,Po-sodepur, Dist 24 parganas(north),Kol-110,West Bengal, India**ProfessorPranab kumar BhattacharyaMD(cal) FIC Path(India); Professor and Head of Department of Pathology [course coordinator of DCP course of  West Bengal University of Health sciences(WBUHS); member secretary of  Board of Studies for DCP course and member of Board of Studies for undergraduate, Post graduate & Doctoral courses in Pathology Discipline  of WBUHS],School of Tropical Medicine, 108 CR Avenue ,Kolkata-73, West Bengal , India,** Miss Upasana Bhattacharya- Student, Mahamayatala, Garia, kol-86, Only daughter of Prof.PK Bhattacharya ***Mr.Ritwik Bhattacharya B.com(cal) of Residence 7/51 Purbapalli, Po-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**** Miss Oaindrila Mukherjee- BA(hons)cal Student,  ****Miss Ayshi Mukherjee –Student of residence Swamiji Road, South Habra, 24 Parganas(north), West Bengal, India ***Miss Rupsa Bhattacharya and ***Mr Somyak Bhattacharya BHM(IGNOU) Msc student(PUSHA) of 7/51 Purbapalli PO-Sodepur Dist 24 Parganas(north) Kolkata-110 West Bengal, India and Mrs Runa Mitra of BK Mitra Social Worker Barrackpore 


Age of Universe & Hubble constant=The universe started at 20x1010 (20,0000 millions years ) ago but there are still uncertainty about the ages of the universe according these authors. Determination of Hydrogen molecule suggest that H~50Km/s-1MPC-10H-1=20x109 years, while age old galactic clusters NGC is 10x109 years and the age of elements obtained from the active isotopes were ~10x109 years. The Freidman and Le -maitre models of universe tell us that the universe however has a finite age and it must be either expanding or contracting. The observation that galaxies are in red shift having special features of shifted to redder wave length in an apparent Doppler recession, strongly support the expanding universe model. Confidence in the Friedman- le-maitre model was strengthening further when Edwin Hubble discovered the near relation between red shift and distances in galaxies in 1929. Hubble discovered a cosmological constant and this constant is proportionally is known widely as Hubble constant. The H(0) is usually expressed in terms of Kilometers per second per mega Per sec ie 50 Km/s/MPC Hubble constant. The Hubble parameter is defined as H(t)=1/R(t)xdR(t)/dt, where R(t) is the scale factor of the universe. Hubble constant is the current value of that parameter and defined as H0=H(now)= velocity/distance and is estimated by measuring the velocity and distance of extra galactic objects. Hubble constant is perhaps the most important parameter in cosmology because it not only provide us the physical scale of the universe which affects the observed absolute size, dynamical mass and luminosity of extra galactic objects but it also provide us estimated age of the universe. The Hubble constant has the units of inverse time. An estimate of the age of the universe is the Hubble time 1/H0. This is the approximate age of a nearly empty universe one, where expansion had not significantly been solved by its mass energy content. A new Model called Ω=1 model, whereΩ is ratio of the universe mass energy density to the critical value required for binding. In the Friedman- Le maitre models the expansion rate of the universe approaches 0 as time approaches  and the current age of the universe  will be  then(2/3) H0-1 is then Age=1/H0[(1-2q0)-1-q0(1-2q0)-3/2 cos h-1(1/q0-1)] where the de-acceleration parameter q0 is (1/2)Ω the ratio of the universe mean mass density to the closer density[ Bhattacharya Rupak and Bhattacharya Pranab Kumar-unpublished data & equation Published  in this blog  Do not try to do plagiarism]
 The age of the universe when H0 is of 50KmS-1MPC-1 gives an age of near 20 billions years while an H0 of 10050KmS-1MPC-1 in an empty universe roughly correspond to an age of 10 billion years. But the Cepheid variables are the bright stars where brightness varies periodically on time scale between one and hundred days. The period of Cepheid is very tightly correlated with its brightness. So they are the excellent indicators of distances of expanding universe and also the age of the universe. Cephids are most distant galaxies of the observable universe and are figured prominently in the extragalactic distance scale. Cepheid first gave us the idea that other galaxies lay outside our Milky way galaxy. Virgo cephid or Virgo  galaxy clusters are so far farthest, twice as far as the most distant previously measured cephids. They are now measured by Hubble Space Telescope(HST). New example of Virgo cephid H0=87± 7 Kms-1MPC-1. The galaxy there NGC 4571 is in the core of Virgo clusters galaxy. Again Taking H0 as H0=87± 7 Kms-1MPC-1 as short value ( H0=80-100 Kms-1MPC-1)
 [Picture of Virgo clusters of galaxy  taken by Rupak Bhattacharya]

and long value H0=50 Kms-1MPC-1) will after the age of the universe for 20 billions years to 11.2±0.9 billions years and 7.3±billions years for Ω=0 model and Ω=1 model respectively. The absence of accelerating force for the age of universe is less then 1/H0 and in standard Big Bang Model is 2/3x1/H0 0r 7x109 years. In contrast some stars are thought to be 8x109 years old, .So here starts the crisis regarding the age of the universe what these authors feels. In Freidman Universe model, Freidman et al calculated Ho=80+17 Kms-1MPC-1 implying the age of the universe 9x109 years. In that  case, identifying 20 cephid variables in m 100 a beautiful spiral galaxy in Virgo. However if we are ready to accept the theory that age of the universe is estimated from the cosmological model based on Hubble constant, as per this model the age of universe will be 13.7±0.2GYR ie 13.7 billions years old.

Though a big bang like event happened in the early universe, universe spent a period of time in the early phase (1s Planck’s time) in a super cooled stage[About 400,000 years after the Big Bang, that the cosmos had cooled sufficiently for protons and electrons to recombine into atoms]. In the super cooled stage its density (3K) was then dominated by large positive constant vacuum energy and false vacuum. The super cooled stage was then followed by appearance of multiple bubbles inflation. The temperature variation occurred in 3K cosmological background imprinted some 10~35 second in pre- inflationary stage and grand unified theory [GUT] happened there with generation of trillions and trillions degrees of temperature. As per old inflationary theory of Big Bang, there appeared multiple bubbles of true vacuum and inflation blowed up a small casually connected region of the universe that was some thing much like the observable universe of today. This actually preceded large scale cosmological homogeneity & were reduced to an exponentially small number the present density of any magnetic monopoles, that according to many of particle physicists GUT & would have been produced in the pre-inflationary phase. In the old inflationary theory the universe must be homogeneous in all its direction and was no doubt isotropic. In old inflation theory, the super cooled stage was married by appearance of bubbles of the true vacuum, the broken symmetry of ground state. The model of old inflation theory however was later on abandoned, because the exponential expansion of any super cooled state always present the bubbles from merging and complicate the phase transition. More over in true sense, universe is not totally homogenous but in small scale non homogenous too.
It is very much a well known fact that universe contain a critical density of matter (3K) and infinite space-time. The matters are mostly baryonic and Mixed Dark matter [MDM]. Through COBE satellite studies, we know that the early universe was consisted of mixture of Cold Dark matter and hot dark Matter, which is known altogether as Mixed Dark Matter [MDM]. Most Red shift survey had been either shallow (Z=<0.03), three dimensional survey of few thousands of galaxies covering a large angle or somewhat deeper (Z>0.05). So argument  still persist about the mechanism by which galaxies/first generation stars were formed in the early universe?. The essence of the problem is so high level physics that while galaxies were on average, uniformly distributed through out the volume of the universe, as it should be in the Inflationary “ Big Bang” model, the observed distribution of both optically visible and radio galaxies on the sky were not uniform. But very much patchy( Authors Prof Pranab Kumar Bhattacharya’s Concept only). Does this clumsiness’ represent that the distribution of matter at some primeval stage in the evolution of the universe or there had been some kind of gravitational process?. Ostriker and cowie in the journal Astrophysics (Vol 243; P127; 1981) had suggested that the present distribution of galaxies are in the relic of a dynamic process, in which an outward propagating shock wave created an earlier generation of galaxies. Created galaxies at some places were of high density on shock front. But the problem of their theory to present authors are that the empirical rule, which says that the chance finding of a second galaxy within same value unit at a distance of “S” is proportional to an inverse power of ”S”, which simply means that there is a greater chance that galaxies will be close together than it is far apart. Secondly the distribution of galaxies in the universe may have a fractal three-dimensional structure. The most spectacular of large voids in three dimensions of galaxies is the BOTES VOID. -A region at least 50 MPS in diameter that contain no luminous galaxies. Why? A survey of large-scale galaxies distributions reveals that the “ Large Voids “ were not the exception, but the rule. The survey was the systemic collection of Red Shifts of all galaxies of apparent magnitude brightness than 15.5 in a region measuring 6 degrees by 12 degrees on the sky. These Red Shifts via “Hubble laws” provides us a three dimensional map of galaxy distribution in a limited volume of the universe. Inspection of the map of the galaxy revealed a striking result- large apparently empty, quase spherical “Voids” dominate space & time and galaxies are crammed into the thin shits and ridges in between hole. (Joseph Sick- Nature-Vol.320; P12; 1986) Joseph Sick discussed in his article published in Nature (Vol 320; p12; 1986) that galaxies were distributed in a thin slice of universe to 150 MPC. The red shift measurement of galaxies however reveals a foamy and clustered distribution of galaxies in the universe. Most of them lying on a sheet, surrounding large, almost empty holes up to 50 MPC According to Ostriker and Cowie, an explosion initiated by many supernovas in a newly formed galaxy drive a blast wave, which propagated outward and swept up a spherical shell of ambient gas. A hole was thus evacuated and the unstable compressed shell fragmented to form more galaxies. These in turn developed blast waves and a series of bubbles developed that filled most of the spaces with galaxies (Jeremiath Ostriker & Lennoy Cowie- Astrophysics journal letter Vol 243; P127; 1981) and published independently by Satron Ikeuchi-Astronomical Society of Japan Vol, 33; P211; 1981) But the problem of this hypothesis before present authors are * 1) possibility of the mechanism itself- Supernova exploded and cleared out holes that are tens or in rare cases hundreds of parsec cross? And* 2) did this phenomenon really worked out on scale of MPC? *3) Billions of supernovae were presumed to be exploded coherently over the crossing time of galaxy of about 108 years to yield a vast explosion 4) Next is the missing ingredients which is Gravity. Density fluctuations were present at the beginning of the time in the earliest instants of the” Big Bang gospel” and the gravity amplified the fluctuation into large-scale structure of the universe. Most cosmologists& theoretical physicists believe today that galaxies were originated in this manner rather then by explosive amplification of primordial seeds which themselves must be attributed into initial condition.
A “giant hole” in the universe had been a discovered by astronomers from Minnesota in 2009 January. Investigating an area of the sky known as the WMAP Cold Spot, Lawrence Rudnick and colleagues found a void empty of stars, gas and even dark matter. As AP’s widely circulating report notes, the hole is big: an “expanse of nearly 6 billion trillion miles of emptiness” Astronomers have long known that there are big voids in the universe, and think they can explain them with their theories as to how large scale structures first formed.[ Plenty of nothing - August 24, 2007The Great Beyond Nature.Com http://blogs.nature.com/cgi-bin/mt/mt-tb.cgi/3329].our Galaxy, the Milky Way, contains also disks of ‘dark matter. Dark’ matter is always invisible but its presence can be inferred through its gravitational influence on its surroundings. Dark matter particles is neutral it does not couple directly to the electromagnetic field, and hence annihilations straight into two monochromatic photons (or a photon and a Z boson) are typically strongly suppressed. γ-rays can be a significant by-product of dark matter annihilations, since they can arise either from the decay of neutral pions produced in the hadronization of the annihilation products, or through internal bremsstrahlung associated into charged particles, with annihilations into charged particles, interactions of energetic leptons. In the Lattanzi & Silk models the annihilation results in two neutral Z bosons Or a pair of W+ and W. bosons, and the dominant source of γ-rays is neutral pion decay. Form_ = 4.5 TeV, every annihilation results in  26 photons with energies between 3 and 300GeV.
Physicists today believe that dark matter makes up 22% of the mass of the Universe (compared with the 4% of normal matter and 74% comprising the mysterious ‘dark energy’). But, despite its pervasive influence, even today no-one is sure what dark matter consists of. It was thought that dark matter forms in roughly spherical lumps called ‘halos’, one of which envelopes the Milky Way and other spiral galaxies. Stars and gas are thought to have settled into disks very early on in the life of the Universe and this affected how smaller dark matter halos formed.  Such a theory suggest that most lumps of dark matter in our locality actually merged to form a halo around the Milky Way. But the largest lumps were preferentially dragged towards the galactic disk and were then torn apart, creating a disk of dark matter within the Galaxy. The presence of unseen haloes of Dark matter had long been inferred from high rotation speed of Gas and stars in outer part of spiral galaxies. The volume of density of these dark matter decreases less quickly from the galactic center than does heat luminous mass such as that in stars meaning that dark matter dominates the mass from the center of galaxies. A spiral galaxy is composed of thin disk of young stars called( population I stars) whose local surface brightness falls exponentially with cylindrical distances from galactic center and with height above galactic plane.
 The concept of biasing the formation of large scale structure of universe was first introduced by Nick Kaisar in journal of Astrophysics (Peacock .JA &Heavens A.F- Monday Nottingham. Royal Astronomical Society Vol 217; P805; 1985 &BardenJ. Bond .Jr, Kaiser. N. Eszalay –Journal of Astrophysics). Galaxies were presumed only to form in the rare peaks of an initial gaussian distribution of density fluctuation. The average density of universe is roughly 1031gcm-3 which is less than 10% of critical Density( K) of present universe.[ The matter of which universe is made of 42.3% is CDM matter and 73% is dark energy] Density fluctuation peaks that occurred in a potential large-scale cluster acquired with slight boost that enabled galaxies to form. The biasing hypothesis enhanced the large-scale structure that developed as gravitational forces amplified the initial fluctuations. Biasing hypothesis enabled stimulation of a universe containing “cold Dark Matter” at the critical density, with observational determination of density perturbation of the universe. Density Fluctuation was present at the beginning of Time in the earliest instants of the Big Bang and the Gravity amplified the fluctuations into large-scale structure of our universe. The “Voids “ were not really voids but contained matter that had some how failed to become luminous. The Dark matter was more uniformly distributed than the luminous matter and does not respond to most of astronomical tests. The universe is now populated with non-luminous component of matter (Dark Matter) made of weakly interacting massive particles which does cluster in galactic scale and designated ΩDM≈0.15-0.35. The dark matter was weakly interacting and was clustered in all scale (hence labeled as cold). It selectively formed galaxies at an early epoch in the rare density peaks. The Cosmic Back ground Explorer study announced on 18th nov’1990 that COBE had used its liquid helium cooled detectors to make stunningly accurate measurement of BIG Bang after glow .The COBE study was based on microwave background radiation that bathes every object in the universe with a cool wash of photon 2.7K. COBE study conferred that the Big Bang was a remarkably smooth and homogeneous event. The COBE study consistently pegged its temperature at about 2.7 K_ what was predicted by Standard Big Bang Model which holds that radiation was emitted by cosmic fire ball just a few hundred years after the Big Bang moment it self and cooling off ever since then. George Smoot[2006 Nobel Laureate in Physics] and his colleagues of Barkley university used differential microwave radiometer to look for anisotropic variations in the brightness of radiation from point to point of the sky. They presumably corresponded to density variation in the cosmic plasma shortly after the Big Bang and these variation are in turn presumably the clumps of matter that CONTRACTED BY GRAVITY TO FORM THE GALAXIES. The problem was that anisotropies if they existed at all, were so weak that it was hard to see now that how they had contracted into much of galaxies. Any clump that was going to form a galaxy needs to be heavy enough to fight cosmic expansion which tends to pull the material apart almost as fast as gravity can pull it together. COBE showed no anisotropy at all to an accuracy of one part in 104to one part 105 and it was DARK MATTER. This Dark matter consisted of some kind of massive but weakly interacting elementary particles produced in the Big Bang. The cosmic back ground explorer study(COBE) satellite study was undertaken by leadership of George Smoot considers the Big Bang very seriously. Microwave Background Study also provided BIG Bang COBE study had spotted millionth of a degree variations in the temperature of microwave left over from Big Bang traces of the early universe .Images of the cosmic microwave background, the radiation left over from the Big Bang, provide the earliest snapshots of the cosmos—from when it was only about 400,000 years old only  The model of MDM of the universe is consistent with homogeneous inflation theory and large-scale density fluctuation and galaxies distribution that happened in the early universe. It was the Merry Gelman, who first described the nature of earliest particles in the universe. According to her “ it was quark particles in quantum theories.” Actually speaking, the quest for the early Universe had provided the particle physicists with an unrivalled accelerator of high-energy particles. The Grand Unification Theory (GUT) based on ‘Gauge Symmetry” say that Proton (Nucleon) should decay with half-life of at most 1031 Years. But while isolating  the rarest events due to  spontaneous decaying of protons, extensive shielding from atmospheric “ Muon” produced by cosmic rays showers were also regarded and primary result once was reported at Geneva, Switzerland. This experiment was carried out us provided in deep underground Kolar Gold field, Kamoka. This experiment provided us the most sensitive limit so far, that the half-life of proton is 1.5x 1032years. This half-life of proton is close to the age of the elements obtained from Radioactive isotopes ~10X109years.This experiments had great implications to astrophysicists in that 1) possible explanation of ratio of proton to photon in the universe. Since the photons now seen in 3K-background radiation are the remnants of equal numbers of particles and antiparticles created during the thermal equilibrium of first instants of the Universe. This particle was Merry Gelman’s quark particles and its antiparticles were antiquarks. Today’s observed proton [matter] represent an excess of matter after antimatter. This is the asymmetry in Universe. This asymmetry probably had arisen naturally after 10-35seconds of initial Big bang. However Madsen and Mark Tailor gave the concept of another particles in the primordial universe. The name of their particles is ‘ Neutrinos”. There are broadly three (3) species of ‘Neutrinos”.  I) Electron neutrinos 2) Muon neutrinos 3) and tat neutrinos. To start the universe i.e. before nucleosynthesis, neutrinos should have a zero mass, which can support at least a hypothesis and theories of large-scale structure of universe. According to Maiden and Tailor, the Dark Matter of which this universe consisted of were the neutrinos and not the quarks.
How did the cosmic Dark Age ended and when did the first star lit up in the universe in a few hundred millions years after the Big Bang?
 According to the standard Model of Big Bang Star formation in the early universe was very different from the present now. Star today form in the giant clouds of molecular gas and dust embedded in the disk of large galaxies like our milky ways. Where as the first stars evolved inside “Mini holes” agglomerates of primoriadial gas and dark matter with a total mass of millions times of our Sun.  Another difference arises for the initial absences of elements, other then hydrogen and helium that were synthesized in the big bang. Gas clouds today be efficiently via radiation emitted by atoms molecule or dust grains that contain heavy elements. Because the primoridial gas lacked those coolants it remained comparatively hot. For gravity to overcome when the higher thermal pressure, the mass of all first stars must had been larger as well. The emergence of first stars fundamentally changed the early universe at the end of cosmic dark ages. Owing to the high masses these stars were copious. They also produced many ultraviolet photons that were energetic enough to ionize hydrogen, the most abundant element in the universe. Thus began the extended process ”re-Ionization” which transformed the universe from the completely cooled and dark material state into fully ionized medium. Observation of CMB due to scattering of CMB photons of free electrons, phase constrains in the onset of re-ionization. How the first stars formed and how they affected the evolution of cosmos assumes that dark matter is made up of WIMP-yet undetected because they interact with normal matter only via gravity and weak nuclear interactions. A possible WIMP candidate is the Neutrions particles, the lightest super partner in mass super symmetry theory but not zero mass particles. Super symmetry postulated that for every known particle there must be a super partner thus affectively doubling mass of the elementary particles. Most of the super particles that were produced after the Big Bang (including Rupak particles also] were unstable and decayed. The neutrinos is expected to be rather massive having roughly the mass of hundred of protons, so are a part of cosmos.
 Most of the matter in the universe did not interact then with light except gravitationally. These dark matter assumed to be very intensively cold, that is its velocity dispersion was sufficiently small for density perturbation imprinted in the early universe to persist in a very small sale. Dark matter has yet to be detected in the human laboratories. However  there might exist some viable dark matter candidates from particle physics that were not cold. They may be termed as Warm Dark Matter(WDM) as per present authors .Warm dark matter particles had intensive thermal velocities and there motion quench the growth of structure bellow a “ free streaming scale”{ the distances over which a typical WDM particles travel}, which depend on the nature of the particle, because small and dark haloes do not form better then free streaming scale. The dark matter haloes that formed the galaxies in a WDM model had far less substructures and were less concentrated as compared to the cold dark matter(CDM) counterparts. The first generation of stars in the universe formed when primoridial gas compressed by falling into these small dark matter potential wells. Large scale partner in the spectrum of density perturbation causes progenitors of present day clusters of galaxies to be among the first objects to condense out of the initially almost smooth mass distribution.
 Lang Gao & Tom Thennus[science 317:14th Sept:Page1527:2007] did studied the early star formation in the red shift Z=0 and they concluded that pristine gas heat and it falls into the dark matter potential Well [halos) cools radiatively because of formation of molecular hydrogen and became self gravitating. They told  another important particle- called- Gravitinos_ a popular WDM candidate particle with mass MWDM=3Kev-a.    a free streaming particle of few +_ evs of kelopersec and first stars at red shift Z~200 and the growth structure re-simulation in the  led to a pattern of filaments and sheets which is familiar form the local large scale distribution of Galaxies. In assumed Gaussian spectrum of density perturbation appropriate for an inflationary model lead collapse along  one(sheet) and two(filaments) direction before formation of Haloes. Altogether the large scale filamentary pattern is very similar in CDM &WDM. This structure of filaments themselves were very different. The CDM filaments fragmented  later into numerous nearly spherical high density regions(haloes) and WDM filaments fragmented at red shift Z=23.34 when universe was 140 millions years old. Gas and Dark matter accreted perpendicular and to filament axis. Dark matter particles falling into filaments performed damped oscillations as the potential well deepened. Baryons did not under go orbit but gas compressed to a temperature T~7000K atγ~ 20Pc. Rapid build up of H2 induced cooling and gas started to dominate the density.
 See the following Links also
http://www.sciencenews.org/view/generic/id/48016/description/
http://phys.org/news162651549.html
http://mnras.oxfordjournals.org/content/378/2/449.full.pd
http://www.firstgalaxies.org/the-early-universe
http://www.sciencenews.org/view/generic/id/48016/description/

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