Advanced search    

Search: authors:"L. Chevallier"

6 papers found.
Use AND, OR, NOT, +word, -word, "long phrase", (parentheses) to fine-tune your search.

An absolute calibration of DENIS (deep near infrared southern sky survey)

An absolute calibration of the DENIS photometric system is presented. It includes the determination of the overall transmission profiles in the 3 bands, namely i, J and Ks, combining contributions from atmosphere, telescope mirrors, instrument lenses and dichroics, filters, and detectors. From these normalized profiles, isophotal and effective wavelengths are computed, using the...

An absolute calibration of DENIS (deep near infrared southern sky survey)

An absolute calibration of the DENIS photometric system is presented. It includes the determination of the overall transmission profiles in the 3 bands, namely i, J and Ks, combining contributions from atmosphere, telescope mirrors, instrument lenses and dichroics, filters, and detectors. From these normalized profiles, isophotal and effective wavelengths are computed, using the...

Fast 2D non–LTE radiative modelling of prominences - Numerical methods and benchmark results

Context.New high-resolution spectropolarimetric observations of solar prominences require improved radiative modelling capabilities in order to take into account both multi-dimensional – at least 2D – geometry and complex atomic models.Aims.This makes necessary the use of very fast numerical schemes for the resolution of 2D non-LTE radiative transfer problems considering...

Thermal instability in X-ray photoionized media in active galactic nuclei: - influence on the gas structure and spectral features

Context.A photoionized gas in thermal equilibrium can display a thermal instability, with three or more solutions in the multi-branch region of the S-shape curve that gives the temperature versus the radiation-to-gas-pressure ratio. Many studies have been devoted to this curve and to its dependence on different parameters, always in the optically thin case.Aims.The subject of our...

Thermal instability in X-ray photoionized media in active galactic nuclei - II. Role of the thermal conduction in warm absorber

Context. A photoionized gas under constant pressure can display thermal instability with three or more solutions for possible thermal equilibrium. A unique solution of the structure of the irradiated medium is obtained only if electron conduction is considered.Aims. The subject of our study is to estimate how the efect of thermal conduction affects the structure and transmitted...

An absolute calibration of DENIS (deep near infrared southern sky survey)

An absolute calibration of the DENIS photometric system is presented. It includes the determination of the overall transmission profiles in the 3 bands, namely i, J and Ks, combining contributions from atmosphere, telescope mirrors, instrument lenses and dichroics, filters, and detectors. From these normalized profiles, isophotal and effective wavelengths are computed, using the...