Search results for "raga"
showing 10 items of 1852 documents
Multiband RadioAstron space VLBI imaging of the jet in quasar S5 0836+710
2019
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.-- Open Access funding provided by Max Planck Society.
Recognition of polychromatic three-dimensional objects
2004
We propose to use optical multichannel correlation in various chromatic systems to obtain a setup for recognition of polychromatic three-dimensional (3-D) objects based on Fourier-transform profilometry. Because red-green-blue color components are not able to split the luminance information of objects in a defined component, when the 3-D objects are brighter than the reference objects the correlation result gives false alarms. We demonstrate that it is possible to use different color spaces that can split luminance from chromatic information to yield adequate recognition of polychromatic 3-D objects. We show experimental results that prove the utility of the proposed method.
Relativistic beaming and gamma-ray brightness of blazars
2009
We investigate the dependence of gamma-ray brightness of blazars on intrinsic properties of their parsec-scale radio jets and the implication for relativistic beaming. By combining apparent jet speeds derived from high-resolution VLBA images from the MOJAVE program with millimetre-wavelength flux density monitoring data from Metsahovi Radio Observatory, we estimate the jet Doppler factors, Lorentz factors, and viewing angles for a sample of 62 blazars. We study the trends in these quantities between the sources which were detected in gamma-rays by the Fermi Large Area Telescope (LAT) during its first three months of science operations and those which were not detected. The LAT-detected blaz…
Revealing the structure of the lensed quasar Q 0957+561. I. Accretion disk size
2021
We thank the anonymous referee for the helpful comments, and constructive remarks on this manuscript. We thank the GLENDAMA project for making publicly available the monitoring data of Q 0957+561. C.F. gratefully acknowledges the financial support from Tel Aviv University and University of Haifa through a DFG grant HA3555-14/1. E.M. and J.A.M are supported by the Spanish MINECO with the grants AYA2016- 79104-C3-1-P and AYA2016-79104-C3-3-P. J.A.M. is also supported from the Generalitat Valenciana project of excellence Prometeo/2020/085. J.J.V. is supported by the project AYA2017-84897-P financed by the Spanish Ministerio de Economia y Competividad and by the Fondo Europeo de Desarrollo Regi…
Determination of Cl/C and Br/C ratios in pure organic solids using laser-induced plasma spectroscopy in near vacuum ultraviolet
2004
Several solid organic compounds containing bromine and chlorine were analyzed with laser-induced plasma spectroscopy. Emission lines were detected in the near vacuum ultraviolet spectral region by using a gas-purged spectrograph and an intensified charge-coupled device detector. The performance of this setup in the determination of the halides in the organic samples was evaluated. Carbon emission lines in the near vacuum ultraviolet were used as internal standards for the measurement of chlorine and bromine. Linear correlation was found between the carbon and halogen emission signal ratio and the corresponding atomic ratio of the compound.
Laser-induced plasma spectroscopy in near vacuum ultraviolet using ordinary spectrograph and ICCD
2002
An experimental setup to measure laser-induced plasma emission spectra with an ordinary Czerny-Turner spectrograph and intensified charge-coupled device in the near vacuum ultraviolet down to 130 nm is described. Spectra of bromine, chlorine and iodine were recorded to demonstrate the performance of the setup.
A brown dwarf orbiting an M-dwarf:MOA 2009-BLG-411L
2012
Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted.Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit.Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties b…
Search for Gravitational-wave Signals Associated with Gamma-Ray Bursts during the Second Observing Run of Advanced LIGO and Advanced Virgo
2019
We present the results of targeted searches for gravitational-wave transients associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo, which took place from 2016 November to 2017 August. We have analyzed 98 gamma-ray bursts using an unmodeled search method that searches for generic transient gravitational waves and 42 with a modeled search method that targets compact-binary mergers as progenitors of short gamma-ray bursts. Both methods clearly detect the previously reported binary merger signal GW170817, with p-values of <9.38 10-6 (modeled) and 3.1 10-4 (unmodeled). We do not find any significant evidence for gravitational-wave signals associate…
MILES extended: Stellar population synthesis models from the optical to the infrared
2016
We present the first single-burst stellar population models which covers the optical and the infrared wavelength range between 3500 and 50000 Angstrom and which are exclusively based on empirical stellar spectra. To obtain these joint models, we combined the extended MILES models in the optical with our new infrared models that are based on the IRTF (Infrared Telescope Facility) library. The latter are available only for a limited range in terms of both age and metallicity. Our combined single-burst stellar population models were calculated for ages larger than 1 Gyr, for metallicities between [Fe/H] = -0.40 and 0.26, for initial mass functions of various types and slopes, and on the basis …
Non-radial pulsations in be stars. Preparation of the corot space mission
2006
The general objective of the present work is to contribute to the knowledge of the physics of Be Stars. In particular, we are interested in studying and characterizing their pulsational properties. A very suitable tool to reach this goal is the study and analysis of photometric time series with the maximum time baseline, density and photometric accuracy.The space mission COROT scheduled to be launched in December 2006, will provide ultra high precision, relative stellar photometry for very long continuous observing runs. Up to ten stars will be observed in the seismology fields with a photometric accuracy of a few 10-4 and color information during 150 days.The observations of Be stars with …