Publications (921)1824.63 Total impact

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ABSTRACT: We present the results of approximately three years of observations of Planck SunyaevZeldovich (SZ) sources with telescopes at the Canary Islands observatories, as part of the general optical followup programme undertaken by the Planck collaboration. In total, 78 SZ sources are discussed. Deep imaging observations were obtained for most of those sources; spectroscopic observations in either in longslit or multiobject modes were obtained for many. We found optical counterparts for 73 of the 78 candidates. This sample includes 53 spectroscopic redshifts determinations, 20 of them obtained with a multiobject spectroscopic mode. The sample contains new redshifts for 27 Planck clusters that were not included in the first Planck SZ source catalogue (PSZ1). 
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ABSTRACT: By looking at the kinetic SunyaevZeldovich effect (kSZ) in Planck nominal mission data, we present a significant detection of baryons participating in largescale bulk flows around central galaxies (CGs) at redshift $z\approx 0.1$. We estimate the pairwise momentum of the kSZ temperature fluctuations at the positions of the CGC (Central Galaxy Catalogue) samples extracted from Sloan Digital Sky Survey (DR7) data. For the foregroundcleaned maps, we find $1.8$$2.5\sigma$ detections of the kSZ signal, which are consistent with the kSZ evidence found in individual Planck raw frequency maps, although lower than found in the WMAP9yr W band ($3.3\sigma$). We further reconstruct the peculiar velocity field from the CG density field, and compute for the first time the crosscorrelation function between kSZ temperature fluctuations and estimates of CG radial peculiar velocities. This correlation function yields a $3.0$$3.7$$\sigma$ detection of the peculiar motion of extended gas on Mpc scales, in flows correlated up to distances of 80100 $h^{1}$ Mpc. Both the pairwise momentum estimates and kSZ temperaturevelocity field correlation find evidence for kSZ signatures out to apertures of 8 arcmin and beyond, corresponding to a physical radius of $> 1$ Mpc, more than twice the mean virial radius of halos. This is consistent with the predictions from hydro simulations that most of the baryons are outside the virialized halos. We fit a simple model, in which the temperaturevelocity crosscorrelation is proportional to the signal seen in a semianalytic model built upon Nbody simulations, and interpret the proportionality constant as an "effective" optical depth to Thomson scattering. We find $\tau_T=(1.4\pm0.5)\times 10^{4}$; the simplest interpretation of this measurement is that much of the gas is in a diffuse phase, which contributes little signal to Xray or thermal SZ observations. 
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ABSTRACT: We present foregroundreduced CMB maps derived from the full Planck data set in both temperature and polarization. Compared to the corresponding Planck 2013 temperature sky maps, the total data volume is larger by a factor of 3.2 for frequencies between 30 and 70 GHz, and by 1.9 for frequencies between 100 and 857 GHz. In addition, systematic errors in the forms of temperaturetopolarization leakage, analoguetodigital conversion uncertainties, and very long time constant errors have been dramatically reduced, to the extent that the cosmological polarization signal may now be robustly recovered on angular scales $\ell\gtrsim40$. On the very largest scales, instrumental systematic residuals are still nonnegligible compared to the expected cosmological signal, and modes with $\ell < 20$ are accordingly suppressed in the current polarization maps by highpass filtering. As in 2013, four different CMB component separation algorithms are applied to these observations, providing a measure of stability with respect to algorithmic and modelling choices. The resulting polarization maps have rms instrumental noise ranging between 0.21 and 0.27$\,\mu\textrm{K}$ averaged over 55 arcmin pixels, and between 4.5 and 6.1$\,\mu\textrm{K}$ averaged over 3.4 arcmin pixels. The cosmological parameters derived from the analysis of temperature power spectra are in agreement at the $1\sigma$ level with the Planck 2015 likelihood. Unresolved mismatches between the noise properties of the data and simulations prevent a satisfactory description of the higherorder statistical properties of the polarization maps. Thus, the primary applications of these polarization maps are those that do not require massive simulations for accurate estimation of uncertainties, for instance estimation of crossspectra and crosscorrelations, or stacking analyses. 
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ABSTRACT: Scaling relations in the LCDM Cosmology predict that for a given mass the clusters formed at larger redshift are hotter, denser and therefore more luminous in Xrays than their local z~0 counterparts. This effect overturns the decrease in the observable Xray flux so that it does not decrease at z > 1, but instead raises slowly, similar to the SZ signal. Provided that scaling relations remain valid at larger redshifts, Xray surveys will not miss massive clusters at any redshift, no matter how far they are. At the same time, the difference in scaling with mass and distance of the observable SZ and Xray signals from galaxy clusters at redshifts z<2 offers a possibility to crudely estimate the redshift and the mass of a cluster. This might be especially useful for preselection of massive highredshift clusters and planning of optical followup for overlapping surveys in Xray (e.g., by SRG/eRosita) and SZ (e.g. Planck, SPT, ACT and CoRe+). 
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ABSTRACT: We present the implications for cosmic inflation of the Planck measurements of the cosmic microwave background (CMB) anisotropies in both temperature and polarization based on the full Planck survey. The Planck full mission temperature data and a first release of polarization data on large angular scales measure the spectral index of curvature perturbations to be $n_\mathrm{s} = 0.968 \pm 0.006$ and tightly constrain its scale dependence to $d n_s/d \ln k =0.003 \pm 0.007$ when combined with the Planck lensing likelihood. When the high$\ell$ polarization data is included, the results are consistent and uncertainties are reduced. The upper bound on the tensortoscalar ratio is $r_{0.002} < 0.11$ (95% CL), consistent with the Bmode polarization constraint $r< 0.12$ (95% CL) obtained from a joint BICEP2/Keck Array and Planck analysis. These results imply that $V(\phi) \propto \phi^2$ and natural inflation are now disfavoured compared to models predicting a smaller tensortoscalar ratio, such as $R^2$ inflation. Three independent methods reconstructing the primordial power spectrum are investigated. The Planck data are consistent with adiabatic primordial perturbations. We investigate inflationary models producing an anisotropic modulation of the primordial curvature power spectrum as well as generalized models of inflation not governed by a scalar field with a canonical kinetic term. The 2015 results are consistent with the 2013 analysis based on the nominal mission data. 
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ABSTRACT: We present the allsky Planck catalogue of SunyaevZeldovich (SZ) sources detected from the 29 month fullmission data. The catalogue (PSZ2) is the largest SZselected sample of galaxy clusters yet produced and the deepest allsky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external datasets, and is the first SZselected cluster survey containing > 103 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressureprofile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multiwavelength search for counterparts in ancillary data, which makes use of radio, microwave, infrared, optical and Xray datasets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of lowredshift Xray under luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT Xray selected samples. 
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ABSTRACT: We present results based on fullmission Planck observations of temperature and polarization anisotropies of the CMB. These data are consistent with the sixparameter inflationary LCDM cosmology. From the Planck temperature and lensing data, for this cosmology we find a Hubble constant, H0= (67.8 +/ 0.9) km/s/Mpc, a matter density parameter Omega_m = 0.308 +/ 0.012 and a scalar spectral index with n_s = 0.968 +/ 0.006. (We quote 68% errors on measured parameters and 95% limits on other parameters.) Combined with Planck temperature and lensing data, Planck LFI polarization measurements lead to a reionization optical depth of tau = 0.066 +/ 0.016. Combining Planck with other astrophysical data we find N_ eff = 3.15 +/ 0.23 for the effective number of relativistic degrees of freedom and the sum of neutrino masses is constrained to < 0.23 eV. Spatial curvature is found to be Omega_K < 0.005. For LCDM we find a limit on the tensortoscalar ratio of r <0.11 consistent with the Bmode constraints from an analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP data leads to a tighter constraint of r < 0.09. We find no evidence for isocurvature perturbations or cosmic defects. The equation of state of dark energy is constrained to w = 1.006 +/ 0.045. Standard big bang nucleosynthesis predictions for the Planck LCDM cosmology are in excellent agreement with observations. We investigate annihilating dark matter and deviations from standard recombination, finding no evidence for new physics. The Planck results for base LCDM are in agreement with BAO data and with the JLA SNe sample. However the amplitude of the fluctuations is found to be higher than inferred from rich cluster counts and weak gravitational lensing. Apart from these tensions, the base LCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets. 
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ABSTRACT: We predict and investigate four types of imprint of a stochastic background of primordial magnetic fields (PMFs) on the cosmic microwave background (CMB) anisotropies: the impact of PMFs on the CMB spectra; the effect on CMB polarization induced by Faraday rotation; magneticallyinduced nonGaussianities; and the magneticallyinduced breaking of statistical isotropy. Overall, Planck data constrain the amplitude of PMFs to less than a few nanogauss. In particular, individual limits coming from the analysis of the CMB angular power spectra, using the Planck likelihood, are $B_{1\,\mathrm{Mpc}}< 4.4$ nG (where $B_{1\,\mathrm{Mpc}}$ is the comoving field amplitude at a scale of 1 Mpc) at 95% confidence level, assuming zero helicity, and $B_{1\,\mathrm{Mpc}}< 5.6$ nG when we consider a maximally helical field. For nearly scaleinvariant PMFs we obtain $B_{1\,\mathrm{Mpc}}<2.1$ nG and $B_{1\,\mathrm{Mpc}}<0.7$ nG if the impact of PMFs on the ionization history of the Universe is included in the analysis. From the analysis of magneticallyinduced nonGaussianity we obtain three different values, corresponding to three applied methods, all below 5 nG. The constraint from the magneticallyinduced passivetensor bispectrum is $B_{1\,\mathrm{Mpc}}< 2.8$ nG. A search for preferred directions in the magneticallyinduced passive bispectrum yields $B_{1\,\mathrm{Mpc}}< 4.5$ nG, whereas the the compensatedscalar bispectrum gives $B_{1\,\mathrm{Mpc}}< 3$ nG. The analysis of the Faraday rotation of CMB polarization by PMFs uses the Planck power spectra in $EE$ and $BB$ at 70 GHz and gives $B_{1\,\mathrm{Mpc}}< 1380$ nG. In our final analysis, we consider the harmonicspace correlations produced by Alfv\'en waves, finding no significant evidence for the presence of these waves. Together, these results comprise a comprehensive set of constraints on possible PMFs with Planck data. 
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ABSTRACT: We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40 sigma), using temperature and polarization data from the Planck 2015 fullmission release. Using a polarizationonly estimator we detect lensing at a significance of 5 sigma. We crosscheck the accuracy of our measurement using the wide frequency coverage and complementarity of the temperature and polarization measurements. Public products based on this measurement include an estimate of the lensing potential over approximately 70% of the sky, an estimate of the lensing potential power spectrum in bandpowers for the multipole range 40<L<400 and an associated likelihood for cosmological parameter constraints. We find good agreement between our measurement of the lensing potential power spectrum and that found in the bestfitting LCDM model based on the Planck temperature and polarization power spectra. Using the lensing likelihood alone we obtain a percentlevel measurement of the parameter combination Sigma_8 Omega_m^{0.25} = 0.591+0.021. We combine our determination of the lensing potential with the Emode polarization also measured by Planck to generate an estimate of the lensing Bmode. We show that this lensing Bmode estimate is correlated with the Bmodes observed directly by Planck at the expected level and with a statistical significance of 10 sigma, confirming Planck's sensitivity to this known sky signal. We also correlate our lensing potential estimate with the largescale temperature anisotropies, detecting a crosscorrelation at the 3 sigma level, as expected due to dark energy in the concordance LCDM model. 
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ABSTRACT: Planck has mapped the microwave sky in nine frequency bands between 30 and 857 GHz in temperature and seven bands between 30 and 353 GHz in polarization. In this paper we consider the problem of diffuse astrophysical component separation, and process these maps within a Bayesian framework to derive a consistent set of fullsky astrophysical component maps. For the temperature analysis, we combine the Planck observations with the 9year WMAP sky maps and the Haslam et al. 408 MHz map to derive a joint model of CMB, synchrotron, freefree, spinning dust, CO, line emission in the 94 and 100 GHz channels, and thermal dust emission. Fullsky maps are provided with angular resolutions varying between 7.5 arcmin and 1 deg. Global parameters (monopoles, dipoles, relative calibration, and bandpass errors) are fitted jointly with the sky model, and bestfit values are tabulated. For polarization, the model includes CMB, synchrotron, and thermal dust emission. These models provide excellent fits to the observed data, with rms temperature residuals smaller than 4 uK over 93% of the sky for all Planck frequencies up to 353 GHz, and fractional errors smaller than 1% in the remaining 7% of the sky. The main limitations of the temperature model at the lower frequencies are degeneracies among the spinning dust, freefree, and synchrotron components; additional observations from external lowfrequency experiments will be essential to break these. The main limitations of the temperature model at the higher frequencies are uncertainties in the 545 and 857 GHz calibration and zeropoints. For polarization, the main outstanding issues are instrumental systematics in the 100353 GHz bands on large angular scales in the form of temperaturetopolarization leakage, uncertainties in the analogtodigital conversion, and very long time constant corrections, all of which are expected to improve in the near future. 
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ABSTRACT: We have constructed allsky ymaps of the thermal SunyaevZeldovich (tSZ) effect by applying specifically tailored component separation algorithms to the 30 to 857 GHz frequency channel maps from the Planck satellite survey. These reconstructed ymaps are delivered as part of the Planck 2015 release. The ymaps are characterised in terms of noise properties and residual foreground contamination, mainly thermal dust emission at large angular scales and CIB and extragalactic point sources at small angular scales. Specific masks are defined to minimize foreground residuals and systematics. Using these masks we compute the ymap angular power spectrum and higher order statistics. From these we conclude that the ymap is dominated by tSZ signal in the multipole range, 20600. We compare the measured tSZ power spectrum and higher order statistics to various physically motivated models and discuss the implications of our results in terms of cluster physics and cosmology. 
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ABSTRACT: We present the Planck Catalogue of Galactic Cold Clumps (PGCC), an allsky catalogue of Galactic cold clump candidates detected by Planck. This catalogue is the full version of the Early Cold Core (ECC) catalogue, which was made available in 2011 with the Early Release Compact Source Catalogue (ERCSC) and contained 915 high S/N sources. It is based on the Planck 48 months mission data that are currently being released to the astronomical community. The PGCC catalogue is an observational catalogue consisting exclusively of Galactic cold sources. The three highest Planck bands (857, 545, 353 GHz) have been combined with IRAS data at 3 THz to perform a multifrequency detection of sources colder than their local environment. After rejection of possible extragalactic contaminants, the PGCC catalogue contains 13188 Galactic sources spread across the whole sky, i.e., from the Galactic plane to high latitudes, following the spatial distribution of the main molecular cloud complexes. The median temperature of PGCC sources lies between 13 and 14.5 K, depending on the quality of the flux density measurements, with a temperature ranging from 5.8 to 20 K after removing sources with the 1% largest temperature estimates. Using seven independent methods, reliable distance estimates have been obtained for 5574 sources, which allows us to derive their physical properties such as their mass, physical size, mean density and luminosity. The PGCC sources are located mainly in the solar neighbourhood, up to a distance of 10.5 kpc towards the Galactic centre, and range from lowmass cores to large molecular clouds. Because of this diversity and because the PGCC catalogue contains sources in very different environments, the catalogue is useful to investigate the evolution from molecular clouds to cores. Finally, the catalogue also includes 54 additional sources located in the SMC and LMC. 

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ABSTRACT: We study the implications of Planck data for models of dark energy (DE) and modified gravity (MG), beyond the cosmological constant scenario. We start with cases where the DE only directly affects the background evolution, considering Taylor expansions of the equation of state, principal component analysis and parameterizations related to the potential of a minimally coupled DE scalar field. When estimating the density of DE at early times, we significantly improve present constraints. We then move to general parameterizations of the DE or MG perturbations that encompass both effective field theories and the phenomenology of gravitational potentials in MG models. Lastly, we test a range of specific models, such as kessence, f(R) theories and coupled DE. In addition to the latest Planck data, for our main analyses we use baryonic acoustic oscillations, typeIa supernovae and local measurements of the Hubble constant. We further show the impact of measurements of the cosmological perturbations, such as redshiftspace distortions and weak gravitational lensing. These additional probes are important tools for testing MG models and for breaking degeneracies that are still present in the combination of Planck and background data sets. All results that include only background parameterizations are in agreement with LCDM. When testing models that also change perturbations (even when the background is fixed to LCDM), some tensions appear in a few scenarios: the maximum one found is \sim 2 sigma for Planck TT+lowP when parameterizing observables related to the gravitational potentials with a chosen time dependence; the tension increases to at most 3 sigma when external data sets are included. It however disappears when including CMB lensing. 


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ABSTRACT: We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg$^2$ patch of sky centered on RA 0h, Dec. $57.5\deg$. The combined maps reach a depth of 57 nK deg in Stokes $Q$ and $U$ in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2 $\mu$K deg in $Q$ and $U$ at 143 GHz). We detect 150$\times$353 crosscorrelation in $B$modes at high significance. We fit the single and crossfrequency power spectra at frequencies above 150 GHz to a lensed$\Lambda$CDM model that includes dust and a possible contribution from inflationary gravitational waves (as parameterized by the tensortoscalar ratio $r$). We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the $r$ constraint. Finally we present an alternative analysis which is similar to a mapbased cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for $r$, and yields an upper limit $r_{0.05}<0.12$ at 95% confidence. Marginalizing over dust and $r$, lensing $B$modes are detected at $7.0\,\sigma$ significance.Physical Review Letters 02/2015; 114(10). DOI:10.1103/PhysRevLett.114.101301 · 7.73 Impact Factor 
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ABSTRACT: The whole set of INTEGRAL observations of type Ia supernova SN2014J, covering the period 16162 days after the explosion has being analyzed. For spectral fitting the data are split into early and late periods covering days 1635 and 50162, respectively, optimized for Ni56 and Co56 lines. As expected for the early period much of the gammaray signal is confined to energies below $\sim$200 keV, while for the late period it is most strong above 400 keV. In particular, in the late period Co56 lines at 847 and 1248 keV are detected at 4.7 and 4.3 sigma respectively. The lightcurves in several representative energy bands are calculated for the entire period. The resulting spectra and lightcurves are compared with a subset of models. We confirm our previous finding that the gammaray data are broadly consistent with the expectations for canonical 1D models, such as delayed detonation or deflagration models for a nearChandrasekhar mass WD. Late optical spectra (day 136 after the explosion) show rather symmetric Co and Fe lines profiles, suggesting that unless the viewing angle is special, the distribution of radioactive elements is symmetric in the ejecta. 
Article: Gas Density Fluctuations in the Perseus Cluster: Clumping Factor and Velocity Power Spectrum
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ABSTRACT: Xray surface brightness fluctuations in the core of the Perseus Cluster are analyzed, using deep observations with the Chandra observatory. The amplitude of gas density fluctuations on different scales is measured in a set of radial annuli. It varies from 8 to 12 per cent on scales of ~1030 kpc within radii of 30160 kpc from the cluster center and from 9 to 7 per cent on scales of ~2030 kpc in an outer, 60220 kpc annulus. Using a statistical linear relation between the observed amplitude of density fluctuations and predicted velocity, the characteristic velocity of gas motions on each scale is calculated. The typical amplitudes of the velocity outside the central 30 kpc region are 90140 km/s on ~2030 kpc scales and 70100 km/s on smaller scales ~710 kpc. The velocity power spectrum is consistent with cascade of turbulence and its slope is in a broad agreement with the slope for canonical Kolmogorov turbulence. The gas clumping factor estimated from the power spectrum of the density fluctuations is lower than 78 per cent for radii ~30220 kpc from the center, leading to a density bias of less than 34 per cent in the cluster core. Uncertainties of the analysis are examined and discussed. Future measurements of the gas velocities with the AstroH, Athena and SmartX observatories will directly measure the gas densityvelocity perturbation relation and further reduce systematic uncertainties in these quantities. 
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ABSTRACT: We present results of all sky survey, performed with data acquired by the IBIS telescope onboard the INTEGRAL observatory over eleven years of operation, at energies above 100 keV. A catalogue of detected sources includes 132 objects. The statistical sample detected on the timeaveraged 100150 keV map at a significance above 5 sigma contains 88 sources: 28 AGNs, 38 LMXBs, 10 HMXBs and 12 rotationpowered young Xray pulsars. The catalogue includes also 15 persistent sources, which were registered with the significance 4 sigma < S/N < 5 in hard Xrays, but at the same time were firmly detected (>12 sigma) in the 1760 keV energy band. All sources from these two groups are known Xray emitters, that means that the catalogue has 100% purity in respect to them. Additionally, 29 sources were found in different time intervals. In the context of the survey we present a hardness ratio of galactic and extragalactic sources, a LMXBs longitudinal asymmetry and a numberflux relation for nonblazar AGNs. At higher energies, in the 150300 keV energy band, 25 sources have been detected with a signaltonoise ratio S/N > 5 sigma, including 7 AGNs, 13 LMXBs, 3 HMXBs, and 2 rotationpowered pulsars. Among LMXBs and HMXBs we identified 12 black hole candidates (BHC) and 4 neutron star (NS) binaries.
Publication Stats
8k  Citations  
1,824.63  Total Impact Points  
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Institutions

1970–2015

Space Research Institute
Moskva, Moscow, Russia


2000–2014

Max Planck Institute for Astrophysics
Arching, Bavaria, Germany 
Institute of Control Sciences
Moskva, Moscow, Russia 
Università degli Studi di Torino
Torino, Piedmont, Italy


1990–2014

Russian Academy of Sciences
 Space Research Institute
Moskva, Moscow, Russia


2010

Max Planck Institute for Extraterrestrial Physics
Arching, Bavaria, Germany


2009

Technische Universität München
 Excellence Cluster Universe
München, Bavaria, Germany


1993–2005

HarvardSmithsonian Center for Astrophysics
Cambridge, Massachusetts, United States 
University of California, San Diego
San Diego, California, United States 
Institut de France
Lutetia Parisorum, ÎledeFrance, France


2004

NASA
Вашингтон, West Virginia, United States 
Lomonosov Moscow State University
Moskva, Moscow, Russia


1998

University of Helsinki
Helsinki, Uusimaa, Finland


1994

University of California, Santa Cruz
Santa Cruz, California, United States 
Paul Sabatier University  Toulouse III
Tolosa de Llenguadoc, MidiPyrénées, France


1991–1994

University of Birmingham
Birmingham, England, United Kingdom


1989–1994

University of Tuebingen
 Institute for Astronomy and Astrophysics
Tübingen, BadenWürttemberg, Germany


1991–1993

Atomic Energy and Alternative Energies Commission
Fontenay, ÎledeFrance, France
