A space-based decametric wavelength radio telescope concept     

K. Belov  A. Branch  S. Broschart  J. Castillo-Rogez  S. Chien  L. Clare  R. Dengler  J. Gao  D. Garza  A. Hegedus  S. Hernandez  S. Herzig  T. Imken  H. Kim  S. Mandutianu  A. Romero-Wolf  S. Schaffer  M. Troesch  E. J. Wyatt  J. Lazio 《Experimental Astronomy》2018,46(2):241-284

This paper reports a design study for a space-based decametric wavelength telescope. While not a new concept, this design study focused on many of the operational aspects that would be required for an actual mission. This design optimized the number of spacecraft to insure good visibility of approx. 80% of the radio galaxies– the primary science target for the mission. A 5,000 km lunar orbit was selected to guarantee minimal gravitational perturbations from Earth and lower radio interference. Optimal schemes for data downlink, spacecraft ranging, and power consumption were identified. An optimal mission duration of 1 year was chosen based on science goals, payload complexity, and other factors. Finally, preliminary simulations showing image reconstruction were conducted to confirm viability of the mission. This work is intended to show the viability and science benefits of conducting multi-spacecraft networked radio astronomy missions in the next few years.  相似文献   

Deciphering neotectonics from river profile analysis in the karst Jura Mountains (northern Alpine foreland)     

Mickael Rabin  Christian Sue  Pierre G. Valla  Jean-Daniel Champagnac  Nicolas Carry  Vincent Bichet  Urs Eichenberger  Jacques Mudry 《Swiss Journal of Geoscience》2015,108(2-3):401-424

  相似文献   

Environment and mass dependencies of galactic λ spin parameter: cosmological simulations and observed galaxies compared     

B. Cervantes-Sodi  X. Hernandez  Changbom Park  Juhan Kim 《Monthly notices of the Royal Astronomical Society》2008,388(2):863-872

We use a sample of galaxies from the Sloan Digital Sky Survey (SDSS) to search for correlations between the λ spin parameter and the environment and mass of galaxies. In order to calculate the total value of λ for each observed galaxy, we employed a simple model of the dynamical structure of the galaxies, which allows a rough estimate of the value of λ using only readily obtainable observables from the luminous galaxies. Use of a large volume-limited sample (upwards of 11 000) allows reliable inferences of mean values and dispersions of λ distributions. We find, in agreement with some N -body cosmological simulations, no significant dependence of λ on the environmental density of the galaxies. For the case of mass, our results show a marked correlation with λ, in the sense that low-mass galaxies present both higher mean values of λ and associated dispersions, than high-mass galaxies. These results provide interesting constrain on the mechanisms of galaxy formation and acquisition of angular momentum, a valuable test for cosmological models.  相似文献   

GHASP: an Hα kinematic survey of spiral and irregular galaxies – VI. New Hα data cubes for 108 galaxies     

B. Epinat  P. Amram  M. Marcelin  C. Balkowski  O. Daigle  O. Hernandez  L. Chemin  C. Carignan  J.-L. Gach  P. Balard 《Monthly notices of the Royal Astronomical Society》2008,388(2):500-550

  相似文献   

High‐resolution seismic monitoring of instrumented buildings using a model‐based state observer          下载免费PDF全文

K. Erazo  E. M. Hernandez 《地震工程与结构动力学》2016,45(15):2513-2531

This paper proposes a model‐based state observer to perform high‐definition response estimation in partially instrumented building structures. The proposed estimator is verified in a simulated five‐story shear‐building structure and validated using measurements from a seven‐story reinforced concrete building slice tested at the NEES‐University of California at San Diego shake table. In both cases the proposed estimator yielded satisfactory results by estimating the time history of shear forces, bending moments, displacements, and strains at various points/sections of interest. The proposed algorithm can be used in instrumented buildings for various practical applications such as post‐earthquake damage assessment, structural control, and building code calibration. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Relationship between volcanic ash fallouts and seismic tremor: quantitative assessment of the 2015 eruptive period at Cotopaxi volcano,Ecuador     

Benjamin Bernard  Jean Battaglia  Antonio Proaño  Silvana Hidalgo  Francisco Vásconez  Stephen Hernandez  Mario Ruiz 《Bulletin of Volcanology》2016,78(11):80

  相似文献   

The secondary history of Sutter's Mill CM carbonaceous chondrite based on water abundance and the structure of its organic matter from two clasts     

P. Beck  E. Quirico  A. Garenne  Q.‐Z. Yin  L. Bonal  B. Schmitt  G. Montes‐Hernandez  G. Montagnac  R. Chiriac  F. Toche 《Meteoritics & planetary science》2014,49(11):2064-2073

Sutter's Mill is a regolith breccia composed of both heavily altered clasts and more reduced xenoliths. Here, we present a detailed investigation of fragments of SM18 and SM51. We have characterized the water content and the mineralogy by infrared (IR) and thermogravimetric analysis (TGA) and the structure of the organic compounds by Raman spectroscopy, to characterize the secondary history of the clasts, including aqueous alteration and thermal metamorphism. The three methods used in this study suggest that SM18 was significantly heated. The amount of water contained in phyllosilicates derived by TGA is estimated to be approximately 3.2 wt%. This value is quite low compared with other CM chondrites that typically range from 6 to 12 wt%. The infrared transmission spectra of SM18 show that the mineralogy of the sample is dominated by a mixture of phyllosilicate and olivine. SM18 shows an intense peak at 11.2 μm indicative of olivine (Fig. 1). If we compare SM18 with other CM and metamorphosed CM chondrites, it shows one of the most intense olivine signatures, and therefore a lower proportion of phyllosilicate minerals. The Raman results tend to support a short‐duration heating hypothesis. In the I_D/I_G versus FWHM‐D diagram, SM18 appears to be unusual compared to most CM samples, and close to the metamorphosed CM chondrites Pecora Escarpment (PCA) 91008 and PCA 02012. In the case of SM51, infrared spectroscopy reveals that olivine is less abundant than in SM18 and the 10 μm silicate feature is more similar to that of moderately altered CM chondrites (like Murchison or Queen Alexandra Range [QUE] 97990). Raman spectroscopy does not clearly point to a heating event for SM51 in the I_D/I_G versus FWHM‐D diagram. However, TGA analysis suggests that SM51 was slightly dehydrated as the amount of water contained in phyllosilicates is approximately 3.7 wt%, which is higher than SM18, but still lower than phyllosilicate water contents in weakly altered CM chondrites. Altogether, these results confirm that fragments with different secondary histories are present within the Sutter's Mill fall. The dehydration that is clearly observed for SM18 is attributed to a short‐duration heating based on the similarity of its Raman spectra to that of PCA 91008. Because of the brecciated nature of Sutter's Mill and the presence of adjacent clasts with different thermal histories, impacts that can efficiently fragment and heat porous materials are the preferred heat source.  相似文献   

Aquifer Management in South Texas: Advanced Decision Support Systems (AMISTADss)     

E. A. Hernandez  V. Uddameri 《Environmental Earth Sciences》2014,71(6):2489-2490

  相似文献   

Warm gas kinematics in shell galaxies     

R. Rampazzo  H. Plana  M. Longhetti  P. Amram  J. Boulesteix  J.-L. Gach  O. Hernandez 《Monthly notices of the Royal Astronomical Society》2003,343(3):819-830

  相似文献   

On the Newtonian limit and cut-off scales of isothermal dark matter haloes with cosmological constant     

Roberto A. Sussman  Xavier Hernandez 《Monthly notices of the Royal Astronomical Society》2003,345(3):871-882

  相似文献