Rapid evaluation of multifrequency EMI data to characterize buried structures at a historical Jesuit Mission in Argentina

We present results from a geophysical prospection at a historical Jesuit Mission, located in San Ignacio (Misiones-Argentina), declared World Monument some years ago. We studied different sectors looking for buried structures; the total area under study covered 36 ha. In this work we will show the results obtained in a sector that at the time of the prospection was at imminent risk of being damaged by a wrong management of the historical resource. To optimize the data acquisition and the preliminary in-situ analysis of the results, we performed an electromagnetic survey using a multifrequency electromagnetic induction device (GEM-2) to have a first insight of the near surface electrical distribution. From 2D and 3D visualization of data, different targets were identified as possible historical structures. Around these anomalous zones, we performed different dipole–dipole profiles, forming high resolution grids for later 3D inversions. Further inversions of the electric and electromagnetic data completed the characterization of the anomalies. One of the main results of this work is that the 3D electric image obtained from 1D inversion of electromagnetic data coincides with the 3D images obtained from resistivity inversion, but at a much less time consuming cost.     

Interpretation of frequency-dependent transmission-lossinterference patterns

Experimental observations of broad-band acoustic propagation in a known geological region of the Atlantic Generating Station (AGS) site (1994) has prompted a new approach to understanding frequency-dependent behavior in shallow-water regions. A modal-based theory is presented to explain quantitatively the interference patterns of transmission loss versus frequency observed in the experimental data. It is shown that the higher modes are responsible for observed interference patterns and that these can be related to modal group velocities using an ideal waveguide model. This may provide new insights applicable to existing inverse techniques     

The flaminio obelisk in Rome: Vibrational characteristics as part of preservation efforts

The purpose of the paper is to study the vibrational characteristics of the Flaminio Obelisk in Rome as part of general studies being performed for preservation purposes. The scope of the paper is limited to dynamic analysis using a finite element model and comparison of the results with those from the measured response to forced vibrations. The state of preservation of the monument is described as well as the sonic method used to evaluate the integrity of the sections. The results of the sonic tests are used to determine reductions in the cross-sectional properties. A stick model including two rotational frequency independent soil springs at the basement level of the obelisk is developed. A good agreement between the numerical and the experimental results is obtained for the natural frequencies and for the modal shapes. A response spectrum and stress analysis according to the Italian Seismic Code is performed considering and evaluating the degraded characteristics of sections.     

X‐ray luminosity functions of different morphological and X‐ray type AGN populations

Luminosity functions are one of the most important observational clues when studying galaxy evolution over cosmic time. In this paper we present the X‐ray luminosity functions for X‐ray detected AGN in the SXDS and GWS fields. The limiting fluxes of our samples are 9.0 ×10^–15 and 4.8 ×10^–16 erg cm^–2 s^–1 in the 0.5–7.0 keV band in the two fields, respectively. We carried out analysis in three X‐ray bands and in two redshift intervals up to z ≤ 1.4. Moreover, we derive the luminosity functions for different optical morphologies and X‐ray types. We confirm strong luminosity evolution in all three bands, finding the most luminous objects at higher redshift. However, no signs of density evolution are found in any tested X‐ray band. We obtain similar results for compact and early‐type objects. Finally, we observe the “Steffen effect”, where X‐ray type‐1 sources are more numerous at higher luminosities in comparison with type‐2 sources. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The CIDA–UCM–Yale shallow survey for emission-line galaxies

We present the CIDA–UCM–Yale (Centro de Investigaciones de Astronomía, Universidad Complutense de Madrid, and Yale University) Survey (CUYS) for Hα+[N  ii ] 6549, 6584 Å emission-line galaxies (ELGs) using objective-prism spectra. The most important properties of a catalogue with 427 entries and significant subsets are analysed. The complete sample contains 183 statistically confirmed ELGs in a sky area of 151 deg² and redshift up to 0.14. We determine the parameters of the Hα luminosity function using the Hα+[N  ii ] flux directly measured on the ELG spectra in this sample, and the star formation rate density derived is in agreement with values reported in the literature. Finally, we study the clustering properties of local star-forming galaxies relative to quiescent ones from different perspectives. We find that ELGs avoid dense regions of quiescent galaxies and we propose a power-law expression to parametrize the relation between star formation rate density and environment volume density of ELGs.