Advances in Astronomy The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Caravan-Submm, Black Hole Imager in the Andes Wed, 20 Jul 2016 10:05:04 +0000 Imaging a black hole horizon as a shadow at the center of black hole accretion disk is another method to prove/check Einstein’s general relativity at strong gravitational fields. Such black hole imaging is expected to be achievable using a submillimeter wavelength VLBI (very long baseline interferometer) technique. Here, we introduce a Japanese black hole imaging project, Caravan-submm undertaken in the Andes. Makoto Miyoshi, Takashi Kasuga, Jose K. Ishitsuka Iba, Tomoharu Oka, Mamoru Sekido, Kazuhiro Takefuji, Masaaki Takahashi, Hiromi Saida, and Rohta Takahashi Copyright © 2016 Makoto Miyoshi et al. All rights reserved. Kilonova/Macronova Emission from Compact Binary Mergers Thu, 14 Jul 2016 07:15:28 +0000 We review current understanding of kilonova/macronova emission from compact binary mergers (mergers of two neutron stars or a neutron star and a black hole). Kilonova/macronova is emission powered by radioactive decays of -process nuclei and it is one of the most promising electromagnetic counterparts of gravitational wave sources. Emission from the dynamical ejecta of ~0.01 is likely to have a luminosity of ~1040–1041 erg s−1 with a characteristic timescale of about 1 week. The spectral peak is located in red optical or near-infrared wavelengths. A subsequent accretion disk wind may provide an additional luminosity or an earlier/bluer emission if it is not absorbed by the precedent dynamical ejecta. The detection of near-infrared excess in short GRB 130603B and possible optical excess in GRB 060614 supports the concept of the kilonova/macronova scenario. At 200 Mpc distance, a typical peak brightness of kilonova/macronova with ejecta is about 22 mag and the emission rapidly fades to >24 mag within ~10 days. Kilonova/macronova candidates can be distinguished from supernovae by (1) the faster time evolution, (2) fainter absolute magnitudes, and (3) redder colors. Since the high expansion velocity () is a robust outcome of compact binary mergers, the detection of smooth spectra will be the smoking gun to conclusively identify the gravitational wave source. Masaomi Tanaka Copyright © 2016 Masaomi Tanaka. All rights reserved. The Photometric Investigation of V921 Her Using the Lunar-Based Ultraviolet Telescope of Chang’e-3 Mission Wed, 15 Jun 2016 09:26:11 +0000 The light curve of V921 Her in ultraviolet band observed by the Lunar-based Ultraviolet Telescope (LUT) is analyzed by the Wilson-Devinney code. Our solutions conclude that V921 Her is an early type marginal contact binary system with an additional close-in component. The binary system is under poor thermal contact with a temperature difference of nearly 700 K between the two components. The close-in component contributes about 19% of the total luminosity in the triple system. Combining the radial velocity study together with our photometric solutions, the mass of the primary star and secondary one is calculated to be , . The evolutionary scenario of V921 Her is discussed. All times of light minimum of V921 Her available in the bibliography are taken into account and the curve is analyzed for the first time. The most probable fitting results are discussed in the paper, which also confirm the existence of a third component ( year) around the binary system. The period of V921 Her is also undergoing a continuously rapid increase at a rate of , which may be due to mass transfer from the less massive component to the more massive one. Xiao Zhou, Sheng-Bang Qian, Jia Zhang, Lin-Jia Li, and Qi-Shan Wang Copyright © 2016 Xiao Zhou et al. All rights reserved. A Time-Dependent and Cosmological Model Consistent with Cosmological Constraints Wed, 08 Jun 2016 09:19:53 +0000 The prevailing constant cosmological model agrees with observational evidence including the observed red shift, Big Bang Nucleosynthesis (BBN), and the current rate of acceleration. It assumes that matter contributes 27% to the current density of the universe, with the rest (73%) coming from dark energy represented by the Einstein cosmological parameter in the governing Friedmann-Robertson-Walker equations, derived from Einstein’s equations of general relativity. However, the principal problem is the extremely small value of the cosmological parameter (~10−52 m2). Moreover, the dark energy density represented by is presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variable model. Cosmic constraints from action principles require that either both and remain time-invariant or both vary in time. Here, we propose a variable cosmological model consistent with the latest red shift data, the current acceleration rate, and BBN, provided the split between matter and dark energy is 18% and 82%. decreases (, where is the normalized cosmic time) and increases () with cosmic time. The model results depend only on the chosen value of at present and in the far future and not directly on . L. Kantha Copyright © 2016 L. Kantha. All rights reserved. Diverse Features of the Multiwavelength Afterglows of Gamma-Ray Bursts: Natural or Special? Sun, 15 May 2016 08:22:39 +0000 The detection of optical rebrightenings and X-ray plateaus in the afterglows of gamma-ray bursts (GRBs) challenges the generic external shock model. Recently, we have developed a numerical method to calculate the dynamics of the system consisting of a forward shock and a reverse shock. Here, we briefly review the applications of this method in the afterglow theory. By relating these diverse features to the central engines of GRBs, we find that the steep optical rebrightenings would be caused by the fall-back accretion of black holes, while the shallow optical rebrightenings are the consequence of the injection of the electron-positron-pair wind from the central magnetar. These studies provide useful ways to probe the characteristics of GRB central engines. J. J. Geng and Y. F. Huang Copyright © 2016 J. J. Geng and Y. F. Huang. All rights reserved. Adjacent Zero Communication Parallel Cloud Computing Method and Its System for -Body Problem with Short-Range Interaction Domain Decomposition Mon, 21 Mar 2016 10:45:29 +0000 Although parallel computing is used in the existing numerical solutions of -body problem, tons of communications between particles render the parallel efficiency extremely low. Despite the fact that domain decomposition based on short-range interaction is used, when is exceedingly large and lots of communications exist between particles in adjacent areas, the parallel efficiency remains terribly low. This paper puts forward adjacent zero communication parallel cloud computing method for -body problem with short-range interaction domain decomposition. According to this method, the adjacent subblock data are exchanged and redundantly stored without acquiring data from other subblocks in the parallel processing, so the waiting time for data transmission can be saved and hence the parallel processing efficiency can be enhanced substantially. Dingju Zhu Copyright © 2016 Dingju Zhu. All rights reserved. Physical Environment of Accreting Neutron Stars Mon, 21 Mar 2016 09:17:36 +0000 Neutron stars (NSs) powered by accretion, which are known as accretion-powered NSs, always are located in binary systems and manifest themselves as X-ray sources. Physical processes taking place during the accretion of material from their companions form a challenging and appealing topic, because of the strong magnetic field of NSs. In this paper, we review the physical process of accretion onto magnetized NS in X-ray binary systems. We, firstly, give an introduction to accretion-powered NSs and review the accretion mechanism in X-ray binaries. This review is mostly focused on accretion-induced evolution of NSs, which includes scenario of NSs both in high-mass binaries and in low-mass systems. J. Wang Copyright © 2016 J. Wang. All rights reserved. Realization of High Dynamic Range Imaging in the GLORIA Network and Its Effect on Astronomical Measurement Sun, 13 Mar 2016 13:51:32 +0000 Citizen science project GLORIA (GLObal Robotic-telescopes Intelligent Array) is a first free- and open-access network of robotic telescopes in the world. It provides a web-based environment where users can do research in astronomy by observing with robotic telescopes and/or by analyzing data that other users have acquired with GLORIA or from other free-access databases. Network of 17 telescopes allows users to control selected telescopes in real time or schedule any more demanding observation. This paper deals with new opportunity that GLORIA project provides to teachers and students of various levels of education. At the moment, there are prepared educational materials related to events like Sun eclipse (measuring local atmosphere changes), Aurora Borealis (calculation of Northern Lights height), or transit of Venus (measurement of the Earth-Sun distance). Student should be able to learn principles of CCD imaging, spectral analysis, basic calibration like dark frames subtraction, or advanced methods of noise suppression. Every user of the network can design his own experiment. We propose advanced experiment aimed at obtaining astronomical image data with high dynamic range. We also introduce methods of objective image quality evaluation in order to discover how HDR methods are affecting astronomical measurements. Stanislav Vítek and Petr Páta Copyright © 2016 Stanislav Vítek and Petr Páta. All rights reserved. Planar Central Configurations of Symmetric Five-Body Problems with Two Pairs of Equal Masses Tue, 08 Mar 2016 09:38:19 +0000 We study central configuration of a set of symmetric planar five-body problems where the five masses are arranged in such a way that , , and are collinear and , , and are collinear; the two sets of collinear masses form a triangle with at the intersection of the two sets of collinear masses; four of the bodies are on the vertices of an isosceles trapezoid and the fifth body can take various positions on the axis of symmetry both outside and inside the trapezoid. We form expressions for mass ratios and identify regions in the phase space where it is possible to choose positive masses which will make the configuration central. We also show that the triangular configuration is not possible. Muhammad Shoaib, Abdul Rehman Kashif, and Anoop Sivasankaran Copyright © 2016 Muhammad Shoaib et al. All rights reserved. A Hydrodynamical Model of a Rotating Wind Source and Its Effects on the Collapse of a Rotating Core Sun, 27 Dec 2015 11:54:16 +0000 This work presents three-dimensional hydrodynamical simulations with the fully parallel GAGDET2 code, to model a rotating source that emits wind in order to study the subsequent dynamics of the wind in three independent scenarios. In the first scenario we consider several models of the wind source, which is characterized by a rotation velocity and an escape velocity , so that the models have a radially outward wind velocity magnitude given by 1, 2, 4, 6, and 8 times . In the second scenario, we study the interaction of winds emitted from a binary system in two kinds of models: one in which the source remains during the wind emission and a second one in which all the source itself becomes wind. In the third scenario we consider the interaction of a rotating source that emits wind within a collapsing and rotating core. In this scenario we consider only wind models of the second kind built over a new initial radial mesh, such that the angular velocity of the wind is 1, 100, and 1000 times the angular velocity of the core . Guillermo Arreaga-Garcia Copyright © 2015 Guillermo Arreaga-Garcia. All rights reserved. The Impact of KLT Coder on the Image Distortion in Astronomy Tue, 24 Nov 2015 09:27:49 +0000 Presented paper is devoted to the application of Karhunen-Loève transform (KLT) for compression and to study of KLT impact on the image distortion in astronomy. This transform is an optimal fit for images with Gaussian probability density function in order to minimize the root mean square error (RMSE). The main part of the encoder is proposed in relation to statistical image properties. Selected astronomical image processing algorithms are used for the encoder testing. The astrometry and point spread function distortion are selected as the most important criteria. The results are compared with JPEG2000 standard. The KLT encoder provides better results from the RMSE point of view. These results are promising and show the novel approach to the design of lossy image compression algorithms and also suitability for algorithms of image data structuring for retrieving, transfer, and distribution. Petr Pata Copyright © 2015 Petr Pata. All rights reserved. Parameterizing the SFC Baryogenesis Model Tue, 15 Sep 2015 10:40:06 +0000 We have numerically explored the scalar field condensate baryogenesis model for numerous sets of model’s parameters, within their natural range of values. We have investigated the evolution of the baryon charge carrying field, the evolution of the baryon charge contained in the scalar field condensate, and the final value of the generated baryon charge on the model’s parameters: the gauge coupling constant , the Hubble constant at the inflationary stage , the mass , and the self-coupling constants . Daniela Kirilova and Mariana Panayotova Copyright © 2015 Daniela Kirilova and Mariana Panayotova. All rights reserved. Corrigendum to “Regions of Central Configurations in a Symmetric 4 + 1-Body Problem” Sun, 13 Sep 2015 13:52:55 +0000 Muhammad Shoaib Copyright © 2015 Muhammad Shoaib. All rights reserved. The Appearance and Disappearance of Exocomet Gas Absorption Sun, 13 Sep 2015 09:02:13 +0000 CaII K-line (3933 Å) absorption profiles observed towards 15 A-type and two B-type stars with known (or suspected) debris disks, in addition to archival spectral data for three A-type stars, are presented. Inspection of the extracted CaII K-line absorption lines has determined that one late B-type (HD 58647) and four new A-type (HD 56537, HD 64145, HD 108767, and HD 109573) stellar systems exhibit short-term (night-to-night) absorption variation within these profiles. This variability is due to the liberation of gas from falling evaporating bodies (the so-called FEBs activity) on the grazing approach of exocomets towards their parent star. Also we present archival spectra of the FeI λ3860 Å and CaII K-lines towards β Pictoris (HD 39060) that, for the first time, reveal the absorption signatures of FEB activity at similar velocities in both line profiles. FEB-hosting stars seem to be of an earlier type (on average spectral type Al.8 as compared with A3.1) than those where no FEB activity has been observed. This could be due to stellar activity levels (such as chromospheric activity or nonradial pulsations) being of a higher level within the atmospheres of these hotter A-type stars. Barry Y. Welsh and Sharon L. Montgomery Copyright © 2015 Barry Y. Welsh and Sharon L. Montgomery. All rights reserved. Cosmic Rays Report from the Structure of Space Sun, 06 Sep 2015 13:57:49 +0000 Spectrum of cosmic rays follows a broken power law over twelve orders of magnitude. Since ubiquitous power laws are manifestations of the principle of least action, we interpret the spectrum accordingly. Our analysis complies with understanding that low-energy particles originate mostly from rapidly receding sources throughout the cosmos. The flux peaks about proton rest energy whereafter it decreases because fewer and fewer receding sources are energetic enough to provide particles with high enough velocities to compensate for the recessional velocities. Above 1015.6 eV the flux from the expanding Universe diminishes below the flux from the nearby nonexpanding part of the Universe. In this spectral feature, known as the “knee,” we relate to a distance of about 1.3 Mpc where the gravitational potential tallies the energy density of free space. At higher energies particles decelerate in a dissipative manner to attain thermodynamic balance with the vacuum. At about 1017.2 eV a distinct dissipative mechanism opens up for protons to slow down by electron-positron pair production. At about 1019.6 eV a more effective mechanism opens up via pion production. All in all, the universal principle discloses that the broad spectrum of cosmic rays probes the structure of space from cosmic distances down to microscopic details. A. Annila Copyright © 2015 A. Annila. All rights reserved. An Improved Infrared/Visible Fusion for Astronomical Images Wed, 26 Aug 2015 09:34:34 +0000 An undecimated dual tree complex wavelet transform (UDTCWT) based fusion scheme for astronomical visible/IR images is developed. The UDTCWT reduces noise effects and improves object classification due to its inherited shift invariance property. Local standard deviation and distance transforms are used to extract useful information (especially small objects). Simulation results compared with the state-of-the-art fusion techniques illustrate the superiority of proposed scheme in terms of accuracy for most of the cases. Attiq Ahmad, Muhammad Mohsin Riaz, Abdul Ghafoor, and Tahir Zaidi Copyright © 2015 Attiq Ahmad et al. All rights reserved. On the Stability of in the Relativistic R3BP with Oblate Secondary and Radiating Primary Tue, 25 Aug 2015 10:00:47 +0000 We consider a version of the relativistic restricted three-body problem (R3BP) which includes the effects of oblateness of the secondary and radiation of the primary. We determine the positions and analyze the stability of the triangular points. We find that these positions are affected by relativistic, oblateness, and radiation factors. It is also seen that both oblateness of the secondary and radiation of the primary reduce the size of stability region. Further, a numerical exploration computing the positions of the triangular points and the critical mass ratio of some binaries systems consisting of the Sun and its planets is given in the tables. Nakone Bello and Jagadish Singh Copyright © 2015 Nakone Bello and Jagadish Singh. All rights reserved. Nonlinear Stability of the Triangular Libration Points for Radiating and Oblate Primaries in CR3BP in Nonresonance Condition Mon, 24 Aug 2015 11:48:21 +0000 This paper investigates the existence of resonance and nonlinear stability of the triangular equilibrium points when both oblate primaries are luminous. The study is carried out near the resonance frequency, satisfying the conditions , and in circular cases by the application of Kolmogorov-Arnold-Moser (KAM) theory. The study is carried out for the various values of radiation pressure and oblateness parameters in general. It is noticed that the system experiences resonance at for different values of radiation pressures and oblateness parameter. The case corresponds to the boundary region of the stability for the system. It is found that, except for some values of the radiation pressure, and oblateness parameters and for , the triangular equilibrium points are stable. Nutan Singh and A. Narayan Copyright © 2015 Nutan Singh and A. Narayan. All rights reserved. Gamma-Ray Burst in Swift and Fermi Era Mon, 24 Aug 2015 11:16:07 +0000 WeiKang Zheng, Xuefeng Wu, Takanori Sakamoto, Yuji Urata, and Shashi B. Pandey Copyright © 2015 WeiKang Zheng et al. All rights reserved. Utilizing the Updated Gamma-Ray Bursts and Type Ia Supernovae to Constrain the Cardassian Expansion Model and Dark Energy Mon, 24 Aug 2015 09:07:22 +0000 We update gamma-ray burst (GRB) luminosity relations among certain spectral and light-curve features with 139 GRBs. The distance modulus of 82 GRBs at can be calibrated with the sample at by using the cubic spline interpolation method from the Union2.1 Type Ia supernovae (SNe Ia) set. We investigate the joint constraints on the Cardassian expansion model and dark energy with 580 Union2.1 SNe Ia sample and 82 calibrated GRBs’ data . In ΛCDM, we find that adding 82 high- GRBs to 580 SNe Ia significantly improves the constraint on plane. In the Cardassian expansion model, the best fit is and   , which is consistent with the ΛCDM cosmology in the confidence region. We also discuss two dark energy models in which the equation of state is parameterized as and , respectively. Based on our analysis, we see that our universe at higher redshift up to is consistent with the concordance model within confidence level. Jun-Jie Wei, Qing-Bo Ma, and Xue-Feng Wu Copyright © 2015 Jun-Jie Wei et al. All rights reserved. Physics of Gamma-Ray Bursts Prompt Emission Mon, 24 Aug 2015 08:47:58 +0000 In recent years, our understanding of gamma-ray bursts (GRB) prompt emission has been revolutionized, due to a combination of new instruments, new analysis methods, and novel ideas. In this review, I describe the most recent observational results and current theoretical interpretation. Observationally, a major development is the rise of time resolved spectral analysis. These led to (I) identification of a distinguished high energy component, with GeV photons often seen at a delay and (II) firm evidence for the existence of a photospheric (thermal) component in a large number of bursts. These results triggered many theoretical efforts aimed at understanding the physical conditions in the inner jet regions. I highlight some areas of active theoretical research. These include (I) understanding the role played by magnetic fields in shaping the dynamics of GRB outflow and spectra; (II) understanding the microphysics of kinetic and magnetic energy transfer, namely, accelerating particle to high energies in both shock waves and magnetic reconnection layers; (III) understanding how subphotospheric energy dissipation broadens the “Planck” spectrum; and (IV) geometrical light aberration effects. I highlight some of these efforts and point towards gaps that still exist in our knowledge as well as promising directions for the future. Asaf Pe’er Copyright © 2015 Asaf Pe’er. All rights reserved. Reverse Shock Emission in Gamma-Ray Bursts Revisited Mon, 24 Aug 2015 08:42:57 +0000 A generic synchrotron external shock model is the widely preferred paradigm used to interpret the broadband afterglow data of gamma-ray bursts (GRBs), including predicted observable signatures from a reverse shock which have been confirmed by observations. Investigations of the nature of the reverse shock emission can provide valuable insights into the intrinsic properties of the GRB ejecta. Here we briefly review the standard and the extended models of the reverse shock emission, discussing the connection between the theory and observations, including the implications of the latest observational advances. He Gao and Peter Mészáros Copyright © 2015 He Gao and Peter Mészáros. All rights reserved. GRB 130603B: No Compelling Evidence for Neutron Star Merger Mon, 24 Aug 2015 08:34:59 +0000 The near infrared (NIR) flare/rebrightening in the afterglow of the short hard gamma ray burst (SHB) 130603B measured with the Hubble Space Telescope (HST) and an alleged late-time X-ray excess were interpreted as possible evidence of a neutron star merger origin of SHBs. However, the X-ray afterglow that was measured with the Swift XRT and Newton XMM has the canonical behaviour of a synchrotron afterglow produced by a highly relativistic jet. The H-band flux observed with HST 9.41 days after burst is that expected from the measured late-time X-ray afterglow. The late-time flare/rebrightening of the NIR-optical afterglow of SHB 130603B could have been produced also by jet collision with an interstellar density bump. Moreover, SHB plus a kilonova can be produced also by the collapse of a compact star (neutron star, strange star, or quark star) to a more compact object due to cooling, loss of angular momentum, or mass accretion. Shlomo Dado and Arnon Dar Copyright © 2015 Shlomo Dado and Arnon Dar. All rights reserved. Systematic Spectral Lag Analysis of Swift Known- GRBs Mon, 24 Aug 2015 08:33:57 +0000 The difference of photon arrival time, which is known as spectral lag, is well known characteristics of gamma-ray bursts (GRBs). In particular, long duration GRBs show a soft lag which means that high energy photons arrive earlier than soft photons. The lag-luminosity relation is the empirical relationship between the isotropic peak luminosity and the spectral lag. We calculated the spectral lags for 40 known redshift GRBs observed by Swift addition to the previous 31 GRB samples. We confirmed that most of our samples follow the lag-luminosity relation. However, we noticed that there are some GRBs which show a significant scatter from the relation. We also confirm that the relationship between the break time and the luminosity of the X-ray afterglow (so-called Dainotti relation) extends up to the lag-luminosity relation. Yuta Kawakubo, Takanori Sakamoto, Atsumasa Yoshida, and Demos Kazanas Copyright © 2015 Yuta Kawakubo et al. All rights reserved. A New Era of Submillimeter GRB Afterglow Follow-Ups with the Greenland Telescope Mon, 24 Aug 2015 08:30:49 +0000 Planned rapid submillimeter (submm) gamma-ray-bursts (GRBs) follow-up observations conducted using the Greenland Telescope (GLT) are presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high altitude and dry weather porvide excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1) systematic detection of bright submm emissions originating from reverse shock (RS) in the early afterglow phase, (2) characterization of forward shock and RS emissions by capturing their peak flux and frequencies and performing continuous monitoring, and (3) detections of GRBs at a high redshift as a result of the explosion of first generation stars through systematic rapid follow-ups. The light curves and spectra calculated by available theoretical models clearly show that the GLT could play a crucial role in these studies. Yuji Urata, Kuiyun Huang, Keiichi Asada, Hiroyuki Hirashita, Makoto Inoue, and Paul T. P. Ho Copyright © 2015 Yuji Urata et al. All rights reserved. Gamma-Ray Bursts as Multienergy Neutrino Sources Mon, 24 Aug 2015 08:10:58 +0000 We review theoretical models for nonelectromagnetic emission, mainly neutrinos and cosmic rays, from gamma-ray bursts (GRBs). In various stages of the relativistic jet propagation, cosmic-ray ion acceleration and subsequent neutrino emission are expected. GRBs are popular candidate sources of the highest-energy cosmic rays, and their prompt phase has been most widely discussed. IceCube nondetection of PeV neutrinos coincident with GRBs has put interesting constraints on the standard theoretical prediction. The GRB-UHECR hypothesis can critically be tested by future observations. We also emphasize the importance of searches for GeV-TeV neutrinos, which are expected in the precursor/orphan or prompt phase, and lower-energy neutrinos would be more guaranteed and their detections even allow us to probe physics inside a progenitor star. Not only classical GRBs but also low-power GRBs and transrelativistic supernovae can be promising sources of TeV-PeV neutrinos, and we briefly discuss implications for the cumulative neutrino background discovered by IceCube. Katsuaki Asano and Kohta Murase Copyright © 2015 Katsuaki Asano and Kohta Murase. All rights reserved. Estimating Finite Source Effects in Microlensing Events due to Free-Floating Planets with the Euclid Survey Thu, 20 Aug 2015 16:12:59 +0000 In recent years free-floating planets (FFPs) have drawn a great interest among astrophysicists. Gravitational microlensing is a unique and exclusive method for their investigation which may allow obtaining precious information about their mass and spatial distribution. The planned Euclid space-based observatory will be able to detect a substantial number of microlensing events caused by FFPs towards the Galactic bulge. Making use of a synthetic population algorithm, we investigate the possibility of detecting finite source effects in simulated microlensing events due to FFPs. We find a significant efficiency for finite source effect detection that turns out to be between 20% and 40% for a FFP power law mass function index in the range [0.9, 1.6]. For many of such events it will also be possible to measure the angular Einstein radius and therefore constrain the lens physical parameters. These kinds of observations will also offer a unique possibility to investigate the photosphere and atmosphere of Galactic bulge stars. Lindita Hamolli, Mimoza Hafizi, Francesco De Paolis, and Achille A. Nucita Copyright © 2015 Lindita Hamolli et al. All rights reserved. Astronomy and Climate-Earth System: Can Magma Motion under Sun-Moon Gravitation Contribute to Paleoclimatic Variations and Earth’s Heat? Thu, 13 Aug 2015 12:12:05 +0000 Paleoclimate data have yielded variations with periods of ~23, ~40, and ~100 ky. Thermodynamic changes resulting from orbital eccentricity, obliquity, and precession have been ascribed as the cause of the variations although processes within the oceans and atmosphere may have too short memory to explain such variations. In this work, the dynamics of Sun-Moon gravitation (SMG) were explored for a rotating Earth and were determined to have a long memory in magma, a mostly ignored geophysical fluid with a mass ~3,400 times that of the atmosphere plus the oceans. Using the basic motion and gravitation (including obliquity) of the Sun and the Moon, we determined that SMG-induced magma motion could produce paleoclimatic variations with multiple periods (e.g., ~23, ~40, ~80, and ~100 ky), with considerable power for Earth’s heat. Such “reproducible” power could possibly maintain an energetic Earth against collapse, radioactivity, and cooling. Zhiren Joseph Wang and Xiaopei Lin Copyright © 2015 Zhiren Joseph Wang and Xiaopei Lin. All rights reserved. TEC Data Forecasting Using a Novel Nonlinear Model Wed, 29 Jul 2015 09:09:50 +0000 A novel nonlinear TEC forecasting model is proposed in the paper; the main produces of the model are as follows: first the EOF decomposition of TEC data is made, then the genetic algorithm is used to establish the nonlinear time field model, and finally the decomposed space field and the predicted time field are reconstructed to achieve the purpose of forecasting the TEC data. Experiments indicate that the performance of the novel forecasting model is effective and superior to the direct forecasting and linear forecasting models. Jun Wang, Bihua Zhou, and Shudao Zhou Copyright © 2015 Jun Wang et al. All rights reserved. UGC 7639: A Dwarf Galaxy in the Canes Venatici I Cloud Tue, 28 Jul 2015 13:27:36 +0000 We want to get insight into the formation mechanism and the evolution of UGC 7639, a dwarf galaxy in the Canes Venatici I Cloud (CVnIC). We used archival multiwavelength data to constrain its global properties. Ultraviolet images show that UGC 7639 inner regions are composed mostly by young stellar populations. In addition, we used smoothed particle hydrodynamics simulations with chemophotometric implementation to account for its formation and evolution. UGC 7639 is an example of blue dwarf galaxy whose global properties are well matched by our multiwavelength approach, that is, a suitable approach to highlight the evolution also of these galaxies as a class. We found that the global properties of UGC 7639, namely, its total absolute B-band magnitude, its whole spectral energy distribution, and morphology, are well matched by an encounter with a system four times more massive than our target. Moreover, the current star formation rate of the simulated dwarf, ≈0.03 M⊙ yr−1, is in good agreement with our UV-based estimate. We derived a galaxy age of 8.6 Gyr. Following our simulation, the ongoing star formation will extinguish within 1.6 Gyr, thus leaving a red dwarf galaxy. L. M. Buson, D. Bettoni, P. Mazzei, and G. Galletta Copyright © 2015 L. M. Buson et al. All rights reserved.