119414440
Cometary panspermia explains the red rain of Kerala
Red coloured rain occurred in many places of Kerala in India during July to September 2001 due to the mixing of huge quantity of microscopic red cells in the rainwater. Considering its correlation with a meteor airbust event, this phenomenon raised an extraordinary question whether the cells are extraterrestrial. Here we show how the observed features of the red rain phenomenon can be explained by considering the fragmentation and atmospheric disintegration of a fragile cometary body that presumably contains a dense collection of red cells. Slow settling of cells in the stratosphere explains the continuation of the phenomenon for two months. The red cells under study appear to be the resting spores of an extremophilic microorganism. Possible presence of these cells in the interstellar clouds is speculated from its similarity in UV absorption with the 217.5 nm UV extinction feature of interstellar clouds.
118437731
Growth and replication of red rain cells at 121°C and their red fluorescence
We have shown that the red cells found in the Red Rain (which fell on Kerala, India, in 2001) survive and grow after incubation for periods of up to two hours at 121°C . Under these conditions daughter cells appear within the original mother cells and the number of cells in the samples increases with length of exposure to 121°C. No such increase in cells occurs at room temperature, suggesting that the increase in daughter cells is brought about by exposure of the Red Rain cells to high temperatures. This is an independent confirmation of results reported earlier by two of the present authors, claiming that the cells can replicate under high pressure at temperatures upto 300°C. The flourescence behaviour of the red cells is shown to be in remarkable correspondence with the extended red emission observed in the Red Rectagle planetary nebula and other galactic and extragalactic dust clouds, suggesting, though not proving an extraterrestrial origin.
83809193
New biology of red rain extremophiles prove cometary panspermia
This paper reports the extraordinary biology of the microorganisms from the mysterious red rain of Kerala, India. These chemosynthetic organisms grow optimally at an extreme high temperature of 300 degrees C in hydrothermal conditions and can metabolize inorganic and organic compounds including hydrocarbons. Stages found in their life cycle show reproduction by a special multiple fission process and the red cells found in the red rain are identified as the resting spores of these microbes. While these extreme hyperthermophiles contain proteins, our study shows the absence of DNA in these organisms, indicating a new primitive domain of life with alternate thermostable genetics. This new biology proves our earlier hypothesis that these microbes are of extraterrestrial origin and also supports our earlier argument that the mysterious red rain of Kerala is due to the cometary delivery of the red spores into the stratosphere above Kerala.
119347677
On the Shallow Decay of Some GRB Afterglows
Half of the radio afterglows for which there is a good temporal coverage exhibit, after 10 days from the burst, a decay which is shallower than at optical frequencies, contrary to what is expected within the simplest form of the standard model of relativistic fireballs or jets. We investigate possible ways to decouple the radio and optical decays. First, the radio and optical emissions are assumed to arise from the same electron population, and we allow for either a time‐varying slope of the power‐law distribution of electron energy or for time‐varying microphysical parameters. Then we consider two scenarios where the radio and optical emissions arise in distinct parts of the GRB outflow, either because the outflow has an angular structure or because there is a long‐lived reverse shock. We find that only the last scenario is compatible with the observations.
16519092
Analytic Light Curves of Gamma-Ray Burst Afterglows: Homogeneous versus Wind External Media
Assuming an adiabatic evolution of a gamma-ray burst (GRB) remnant interacting with an external medium, we calculate the injection, cooling, and absorption break frequencies and the afterglow flux for plausible orderings of the break and observing frequencies. The analytical calculations are restricted to a relativistic remnant and, in the case of collimated ejecta, to the phase where there is an insignificant lateral expansion. Results are given for both a homogeneous external medium and a wind ejected by the GRB progenitor. We compare the afterglow emission at different observing frequencies, for each type of external medium. It is found that observations at submillimeter frequencies during the first day provide the best way of discriminating between the two models. By taking into account the effect of inverse Compton (IC) scatterings on the electron cooling, a new possible time dependence of the cooling break is identified. The signature of the upscattering losses could be seen in the optical synchrotron emission from a GRB remnant interacting with a preejected wind, as a temporary mild flattening of the afterglow decay. The upscattered radiation itself should be detected in the soft X-ray emission from GRB remnants running into denser external media, starting a few hours after the main event.
118721274
Wounded quarks and multiplicity at relativistic ion colliders
In this paper, we propose a parameterization which is based on a phenomenological model involving the wounded quarks interactions for explaining the average charged particle multiplicity 〈nch〉, the central pseudo-rapidity density 〈(dn/dη)η=0〉 and the complete rapidity dependence of dn/dη in relativistic heavy-ion collider experiments. The model also interrelates nucleus-nucleus (A-A collisions with p-A and p-p interactions. Our parameterization rests on simple assumptions regarding the mean number of participating quarks and their average number of collisions. The results for 〈nch〉 and their variations with the mass number of colliding nuclei, center-of-mass energy (√sNN) and collision centrality are well supported by the available experimental data. Finally we give the predictions from our model for A-A collisions at the Large Hadron Collider (LHC) and Compressed Baryonic Matter (CBM) experiments. Our results indicate the existence of a possible universal production mechanism for p-p, p -A and A-A collisions.
73714687
Charged Hadron Multiplicity Distribution at Relativistic Heavy-Ion Colliders
The present paper reviews facts and problems concerning charge hadron production in high energy collisions. Main emphasis is laid on the qualitative and quantitative description of general characteristics and properties observed for charged hadrons produced in such high energy collisions. Various features of available experimental data, for example, the variations of charged hadron multiplicity and pseudorapidity density with the mass number of colliding nuclei, center-of-mass energies, and the collision centrality obtained from heavy-ion collider experiments, are interpreted in the context of various theoretical concepts and their implications. Finally, several important scaling features observed in the measurements mainly at RHIC and LHC experiments are highlighted in the view of these models to draw some insight regarding the particle production mechanism in heavy-ion collisions.
121869085
Systematic study of multiparticle production in nucleus–nucleus interactions at 14.6 A GeV
An experimental analysis of 855 events induced by 14.6 A GeV 28Si in nuclear emulsion is presented. Mean multiplicities of charged secondary particles produced in the nuclear interactions are studied and compared with the results from the other experiments for the same projectile at 3.7 A GeV as well as data for proton at similar energy (14 GeV). An analysis of pseudorapidity densities of target fragments (black and grey particles) is also performed. The behaviour of the KNO scaling law of the multiplicity distribution for shower particles has been examined. In order to accumulate knowledge about the intermittent behaviour of shower particles, the scaled factorial moments (SFMs) are computed in η-space and ϕ-space for a set of data in the 28Si–AgBr events. Furthermore, validity of limiting fragmentation of shower particles produced in central collision events induced by 28Si-emulsion interactions has been tested. A crude estimation for the energy density of the nuclear matter formed in the central collision events at our energy has been examined.