Jean Clavel - Academia.edu (original) (raw)
Papers by Jean Clavel
Astronomy and Astrophysics, Jun 29, 1989
Les techniques d'etude de la variation de flux des noyaux de galaxies sont analysees. La fonc... more Les techniques d'etude de la variation de flux des noyaux de galaxies sont analysees. La fonction de correlation discrete et la fonction de correlation croisee sont comparees pour le flux UV de la galaxie de Seyfert NGC 5548
Astronomy and Astrophysics, Jul 30, 1991
The emission component in Seyfert galaxies and quasars dominating in the visible-ultraviolet spec... more The emission component in Seyfert galaxies and quasars dominating in the visible-ultraviolet spectral range, the so-called blue bump, has often been associated with thermal emission from the surface of an optically thick and geometrically thin accretion disc. Although the intrinsic shape of the continuum spectral energy distribution is poorly known, some of the spectral properties of AGN are in contradiction with expectations from the model. Furthermore, the observed simultaneity of continuum variations in UV, optical and near IR bands is in clear conflict with model expectations. Though they are still in their infancy, geometrically thick accretion disc models could potentially resolve these discrepancies and account for most of the observed of the continuum emission of quasars and Seyfert galaxies
Fourth European Iue Conference, Jul 1, 1984
Lecture Notes in Physics, 1991
An essential part of the Science Operation Center SOC, the XMM science Archives will be the only ... more An essential part of the Science Operation Center SOC, the XMM science Archives will be the only repository of all XMM scientiic data. All les relevant t o a given observation, from the initial proposal up to the processed data and distribution logs are automatically stored, linked and catalogued such they can easily be retrieved. The archives also encapsulate the SSW and databases necessary to run XMM payload operations. The archives are the only interface between the SOC located in VILSPA, near Madrid, Spain the Mission Operation Center MOC in ESOC, Germany and the Survey Science Center SSC in Leicester, UK. Therefore they play a crucial role in the de-centralised XMM ground segment and ensure that all les, databases and software systems shared by the three centers are identical and under strict connguration control. All science data are stored in FITS format and accessible on line via a web based browser interface. The database management system uses ORACLE and support up to ten ...
The M16 (Eagle nebula) region is a classic star forming region containing a large number of known... more The M16 (Eagle nebula) region is a classic star forming region containing a large number of known young stellar objects (YSOs) and the young stellar cluster, NGC6611. The region contains significant dust and gas that appears shaped by interactions with newly-formed stars. We present analysis of new Herschel Observatory images of an area of 1.5 x 1.5 degrees at five far-infrared wavelengths between 70 and 500 microns. Combining the data in the images we are able to reveal the distribution and nature of the small source (clumped) emission as well as the large-scale structure of the cool dust materials in the region. Maps at multiple infrared wavelengths are used to reveal the general dust temperature variations across the region and density of dust. We also extract the multi-wavelength fluxes for clumps of far-infrared/sub-millimetre emission in the field using a multi-resolution analysis technique, since the resolution of the images varies by a factor of eight over the wavelength ran...
Symposium - International Astronomical Union, 1994
Because they emit copiously over more than 10 decades in frequency, Active Galactic Nuclei (AGN) ... more Because they emit copiously over more than 10 decades in frequency, Active Galactic Nuclei (AGN) cannot be understood without the help of multiwavelength observations. On the other hand, variability monitoring has also proven to be invaluable in understanding the continuum and line emission process as well as the geometry of the innermost regions in these objects. Indeed, at the heart of…
Monthly Notices of the Royal Astronomical Society, 1993
ESA's space science program is briefly reviewed, with a particular emphasis on its long-term ... more ESA's space science program is briefly reviewed, with a particular emphasis on its long-term plan, ``Cosmic Vision 2015-2025''. The mission selection process is presented together with the current status of the different projects selected and currently under assessment. The strategy for implementing the plan is outlined, as well as the programmatic and international context.
The Astrophysical Journal, 1987
IUE spectra of 3C 390.3 obtained at 17 different epochs from 1978 to 1986 show that the flux in t... more IUE spectra of 3C 390.3 obtained at 17 different epochs from 1978 to 1986 show that the flux in the narrow core of the Ly-alpha 1216 A and C IV 1550 A emission lines steadily declined by a factor of 1.7 and 3.2, respectively. Lloyd's optical monitoring reported in 1984 shows that the continuum intensity decreased by 2 mag over
![Research paper thumbnail of An [ITAL]XMM[/ITAL]-[ITAL]Newton[/ITAL] Detection of the [CLC][ITAL]z[/ITAL][/CLC] = 5.80 X-Ray–Weak Quasar SDSS[CLC]p[/CLC] J104433.04-012502.2](https://attachments.academia-assets.com/110735096/thumbnails/1.jpg)
](The Astronomical Journal, 2001
Nature, 1987
If you do not have access to the article you require, you can purchase the article (see below) or... more If you do not have access to the article you require, you can purchase the article (see below) or access it through a site license. A site license includes a minimum of four years of archived content; institutions can add additional archived content to their license at any time. ...
Astronomy and Astrophysics, Jun 29, 1989
Les techniques d'etude de la variation de flux des noyaux de galaxies sont analysees. La fonc... more Les techniques d'etude de la variation de flux des noyaux de galaxies sont analysees. La fonction de correlation discrete et la fonction de correlation croisee sont comparees pour le flux UV de la galaxie de Seyfert NGC 5548
Astronomy and Astrophysics, Jul 30, 1991
The emission component in Seyfert galaxies and quasars dominating in the visible-ultraviolet spec... more The emission component in Seyfert galaxies and quasars dominating in the visible-ultraviolet spectral range, the so-called blue bump, has often been associated with thermal emission from the surface of an optically thick and geometrically thin accretion disc. Although the intrinsic shape of the continuum spectral energy distribution is poorly known, some of the spectral properties of AGN are in contradiction with expectations from the model. Furthermore, the observed simultaneity of continuum variations in UV, optical and near IR bands is in clear conflict with model expectations. Though they are still in their infancy, geometrically thick accretion disc models could potentially resolve these discrepancies and account for most of the observed of the continuum emission of quasars and Seyfert galaxies
Fourth European Iue Conference, Jul 1, 1984
Lecture Notes in Physics, 1991
An essential part of the Science Operation Center SOC, the XMM science Archives will be the only ... more An essential part of the Science Operation Center SOC, the XMM science Archives will be the only repository of all XMM scientiic data. All les relevant t o a given observation, from the initial proposal up to the processed data and distribution logs are automatically stored, linked and catalogued such they can easily be retrieved. The archives also encapsulate the SSW and databases necessary to run XMM payload operations. The archives are the only interface between the SOC located in VILSPA, near Madrid, Spain the Mission Operation Center MOC in ESOC, Germany and the Survey Science Center SSC in Leicester, UK. Therefore they play a crucial role in the de-centralised XMM ground segment and ensure that all les, databases and software systems shared by the three centers are identical and under strict connguration control. All science data are stored in FITS format and accessible on line via a web based browser interface. The database management system uses ORACLE and support up to ten ...
The M16 (Eagle nebula) region is a classic star forming region containing a large number of known... more The M16 (Eagle nebula) region is a classic star forming region containing a large number of known young stellar objects (YSOs) and the young stellar cluster, NGC6611. The region contains significant dust and gas that appears shaped by interactions with newly-formed stars. We present analysis of new Herschel Observatory images of an area of 1.5 x 1.5 degrees at five far-infrared wavelengths between 70 and 500 microns. Combining the data in the images we are able to reveal the distribution and nature of the small source (clumped) emission as well as the large-scale structure of the cool dust materials in the region. Maps at multiple infrared wavelengths are used to reveal the general dust temperature variations across the region and density of dust. We also extract the multi-wavelength fluxes for clumps of far-infrared/sub-millimetre emission in the field using a multi-resolution analysis technique, since the resolution of the images varies by a factor of eight over the wavelength ran...
Symposium - International Astronomical Union, 1994
Because they emit copiously over more than 10 decades in frequency, Active Galactic Nuclei (AGN) ... more Because they emit copiously over more than 10 decades in frequency, Active Galactic Nuclei (AGN) cannot be understood without the help of multiwavelength observations. On the other hand, variability monitoring has also proven to be invaluable in understanding the continuum and line emission process as well as the geometry of the innermost regions in these objects. Indeed, at the heart of…
Monthly Notices of the Royal Astronomical Society, 1993
ESA's space science program is briefly reviewed, with a particular emphasis on its long-term ... more ESA's space science program is briefly reviewed, with a particular emphasis on its long-term plan, ``Cosmic Vision 2015-2025''. The mission selection process is presented together with the current status of the different projects selected and currently under assessment. The strategy for implementing the plan is outlined, as well as the programmatic and international context.
The Astrophysical Journal, 1987
IUE spectra of 3C 390.3 obtained at 17 different epochs from 1978 to 1986 show that the flux in t... more IUE spectra of 3C 390.3 obtained at 17 different epochs from 1978 to 1986 show that the flux in the narrow core of the Ly-alpha 1216 A and C IV 1550 A emission lines steadily declined by a factor of 1.7 and 3.2, respectively. Lloyd's optical monitoring reported in 1984 shows that the continuum intensity decreased by 2 mag over
The Astronomical Journal, 2001
Nature, 1987
If you do not have access to the article you require, you can purchase the article (see below) or... more If you do not have access to the article you require, you can purchase the article (see below) or access it through a site license. A site license includes a minimum of four years of archived content; institutions can add additional archived content to their license at any time. ...