International Conference on Astronomy, Astrophysics and Astrobiology May 30-31,2018 Osaka , Japan

Biography:

Alain Iltis has been In-Charge of developing Lanthanum Halides (LaBr3: Ce) scintillators and radiation detectors for St Gobain crystal. He has done the first LaBr3 PET modules for Joel Karp (U Penn). His expertise is in crystal growth and scintillation based radiation detectors. He had proposed the concept of temporal imaging and Founded Damavan imaging to exploit. He is currently Damavan’s President. He has filed more than 25 patents

Abstract:

Our objective is to promote a Compton camera for the energy range (200 keV- 2 meV) that uses fast scintillating crystals and a new concept for locating scintillation event accurately in thick plates: temporal imaging. We believe this concept could allow cost effective and still efficient imaging systems to be built. Temporal imaging uses monolithic plates of fast scintillators and measures photons time of arrival distribution in order to locate each gamma ray with a high precision in space (X, Y, Z), time (T) and energy (E). This provides a native estimation of the depth of interaction (Z) of every detected gamma ray. This also allows a time correction for the propagation time of scintillation photons inside the crystal, therefore resulting in excellent time resolution. The high temporal resolution of the system makes it possible to veto quite efficiently background by using narrow time coincidence window (<300 ps). It is also possible to reconstruct the direction of propagation of the photons inside the detector using timing constraints. A hand held demonstrator featuring one Compton head with two CeBr₃ crystals 32x32x5 mm then 32x32x20 mm both readout by Phillips DPC Si-PM has been built. We present here preliminary images of a ²²Na source obtained with the 511 keV line. The sensitivity of our system is better than 1 nSv/h in a 60 seconds acquisition with a ²²Na source.

Biography:

Dr. Chan, Man-Ho obtained his Bachelor degree, Master degree and Doctoral degree in physics from The Chinese University of Hong Kong. He also finished his second Doctoral degree in philosophy at Hong Kong Baptist University. He is now an Assistant Professor of Department of Science and Environmental Studies, The Education University of Hong Kong. His research interests include Astrophysics, Cosmology, Philosophy of Science and dialogue between Science and Religion.

Abstract:

Radio observations of nearby galaxies can give stringent constraints for annihilating dark matter. If dark matter particles can annihilate, the high-energy electrons and positrons produced would emit strong synchrotron radiation (in radio waves) due to the strong magnetic field in galaxies. By using the observed radio fluxes emitted from nearby galaxies, we can constrain the annihilation cross sections and dark matter mass for different annihilation channels. In this talk, we report some good target objects for constraining annihilating dark matter and present the latest radio constraints based on the recent radio data

Biography:

Jérôme Pétri is an Expert in Theory and Modeling of Neutron Star Electrodynamics and Relativistic Radiation Mechanisms in strong magnetic fields. He has tackled several problems related to relativistic plasma dynamics with special emphasizes to magneto hydrodynamics and kinetic neutral/non-neutral plasma configurations arising around compact stellar objects, investigating their stability properties. He has also developed himself several algorithm to solve nonstandard relativistic astrophysics plasma problems, like linear dispersion relations for the two-stream and tearing instabilities, evolution of the diocotron and magnetron instabilities in linear and non-linear stages, pulsar magnetosphere including strong gravity and strong electromagnetic field effects. He had computed polarized synchrotron and inverse Compton emission emanating from the striped pulsar wind or from an off-centered magnetic dipole. Recently he computed neutron star magnetospheres in general relativity including quantum electrodynamics corrections and radiation from general-relativistic rotating magnetic multipoles.

Abstract:

Most current pulsar emission models assume photon production and emission within the magnetosphere although recently some attempts were made to explain pulsed emission emanating from the striped wind. Low frequency radiation is preferentially produced in the vicinity of the polar caps whereas the high-energy tail is shifted to regions closer but still inside the light-cylinder (that is within the magnetosphere). We conducted a systematic study of the merit of several popular radiation sites like the polar cap, the outer gap and the slot gap. We computed sky maps emanating from each emission site according to a prescribed distribution function for the emitting particles made of an electron/positron mixture. Calculations are performed using a three dimensional integration of the plasma emissivity in the vacuum electromagnetic field of a rotating centered general relativistic dipole. We compare Newtonian electromagnetic fields to their general relativistic counterpart. In the latter case, light bending is also taken into account. As a typical example, light-curves and sky maps are plotted for several power-law indices of the particle distribution function. The detailed pulse profiles strongly depending on the underlying assumption about the fluid motion subject to strong electromagnetic fields. From this electromagnetic topology we deduced the photon propagation direction directly or indirectly from aberration effects. We also discuss the implication of a net stellar electric charge on to the sky maps. Taking into account the electric field in the photon propagation direction strongly affects the light-curves originating close to the light-cylinder where the electric field strength becomes comparable to the magnetic field strength. We plan to include plasma screening in the force free limit as well as some quantum electrodynamics effects and an off-centered dipole.

Biography:

Abstract:

The binary star Tau Ophiuchi is a difficult system to study. Although 633 observations were made between 1835 and 2014, they do not cover the full period of the orbit, which I calculate as 230.21 years, nor include the time of periastron passage, 1834.55 by my calculations. The difficulty arises from trying to obtain an orbit that statistically satisfies the observations and also the dynamics of binary star motion. The orbit published in the Washington double star catalog fails to satisfy the dynamics because the variation of mean anomaly with time, which should be linear, shows, decided nonlinearity. The best fit orbit I calculate satisfies statistics, with satisfactory randomness of the residuals, but fails dynamically because the orbit is hyperbolic, eccentricity of 1.05, impossibility. By use of semi definite programming to solve for both the orbital elements and the constant of areal velocity I finds an orbit that, although not entirely satisfactory statistically as measured by a statistical test for randomness of the residuals, 259 runs out of an expected 317, results in a mean anomaly that varies linearly with time and thus satisfies the dynamics. The sum of the masses of the two components, 6.07 solar masses, also becomes consistent with the primary, according to observational astronomers, being a giant star, although one cannot calculate the individual masses. The orbit is a high eccentricity ellipse, eccentricity 0.773, with perihelion 211.41, node 60.10 and inclination 54.64, all in degrees. This binary shows the importance of both statistics and dynamics for successful orbit computation.

Biography:

Dr. Yu-Qing Lou, winner of 1981 China-US Physics Examination and Application (CUSPEA) sponsored by Nobel Laureate

Professor T.D. Lee, has completed his physics PhD in 1987 from Harvard University. He became High Altitude Observatory and

Advanced Study Program Fellow at National Center for Atmospheric Research (NCAR) 1987-1989. He has published more than

140 international journal papers (including Nature, Science, The Astrophysical Journal (Letters), Monthly Notices of the Royal

Astronomical Society (Letters), Journal of Geophysical Research, Geophysical Research Letters, Astronomy and Astrophysics).

In 2002, he became distinguished Yangtze Professor in Physics Department of Tsinghua University. He has served in review

panels in USA, China and others.

Abstract:

The background information of stars and galaxies in the cosmos is first described. The physical scenario and the theoretical model framework are then outlined. The basic phenomenology and the key concepts pertinent to density waves and fast and slow magnetohydrodynamic (MHD) density waves for spiral galaxies are presented. Major theoretical results are shown and explained. As examples of astrophysical applications, we discuss multiwavelength diagnostics, hot galactic coronae, inhomogeneous spiral galactic winds, circumnuclear starburst rings in barred spiral galaxies and chains of galaxies among others.

Biography:

Poornima Varma is working as Women Scientist in the Department of Physics at Dr. H. S. Gour Central University, Sagar, Madhya Pradesh in India. She has completed her PhD degree. She has been awarded CSIR National fellowship for her Post-Doctoral work. During her Post-Doctoral tenure she has been awarded best paper presentation award in national conferences and young scientist award by ISCA. She has published more than 98 research papers in cited journals and various national and international conferences. She is life time Member of ISCA, Kolkata and PSSI, Ahmedabad. She had completed 11 major research project as Principal and Co-Principal Investigator and guided PhD student and MSc student regularly. Her research interest in theoretical modulation of plasma approach in space physics, magnetosphere-ionosphere coupling, auroral electrodynamics, earth’s magnetosphere; gas discharge physics, theoretical approaches, atmospheric physics and ultra-low frequency wave phenomena

Abstract:

The study of ultra-low frequency wave phenomena is of global interest. The various international organizations are involved to investigate the same pattern of the instabilities concerning the electromagnetic emissions, plasma transport, micro pulsations and heating of the thermonuclear plasma. The investigation is based upon particle aspect approach as well as kinetic approach which we have been pursuing since last 25 years (e.g. Varma, et al., 1991 and references therein) in various space regions. Shukla et al., (2008) stated that the Polar and Cluster satellites have observed that large amplitude KAWs are observed throughout the plasma sheet, particularly at the plasma sheet boundary layer (PSBL) during substorm (Wygant et al., 2002). Recent investigation by Patel et al., (2011_{a, b}) describes a useful mathematical model developed for hot multi-ion (H⁺, He⁺ and O⁺) plasma to study the electromagnetic ion cyclotron waves in auroral acceleration region and polar cusp region. The effect of increasing electron thermal anisotropies is to enhance the growth rate due to the interaction of electrons with EMIC waves. It is applicable to explain the EMIC wave phenomena in the Earth’s magnetosphere. Agarwal et al., 2012 analyzed the dispersive Alfven wave (DAW) features in auroral acceleration region. The findings indicate that inhomogeneity of magnetosphere may play a significant role in the description of auroral dynamic by DAW. The density and temperature gradients contribute significantly to excite the dispersive Alfven waves in the acceleration region. The role of velocity shear should be taken into account while dealing the dynamics of DAW in the magnetospheric plasmas. The findings of the investigation may be useful for the plasma heating processes, confinement device and the space plasmas. Laboratory plasmas as well as plasmas in space often contain strong gradients perpendicular to the background magnetic field. The outcome of the investigation is anticipated to explain the complexity and diversity of magnetosphere-ionosphere coupling and auroral electrodynamics by studying the wave phenomena of ULF waves at the substorm times which may be useful to study space environment at higher latitudes useful for polar satellites. This study may play a major role to unfold the mystery of substorm behavior effective on earths. This study also may be utilized to explain wave phenomena and acceleration of solar atmosphere and for thermonuclear plasma which are the future energy programs of the next era. The behavior of ultra-low frequency waves are studied in view of Birkeland current system, magnetospheric morphology and auroral acceleration pattern.