Publications (55)
Are quasars accreting at super-Eddington rates?
S. Collin, C. Boisson, M. Mouchet +4
In a previous paper, Collin & Huré (2001), using a sample of Active Galactic Nuclei (AGN) where the mass has been determined by reverberation studies (Kaspi et al. 2000), have sho…
Identification of backgrounds in the EDELWEISS-I dark matter search experiment
S. Fiorucci, A. Benoit, L. Berge +36
This paper presents our interpretation and understanding of the different backgrounds in the EDELWEISS-I data sets. We analyze in detail the several populations observed, which inc…
Role of commensurate arrangements in the optical response of metallic gratings
A. Barbara, J. Le Perchec, P. Quemerais +4
Light localization on commensurate arrangements of metallic sub-wavelength grooves is studied. We theoretically show that as the degree of commensuration tends to an irrational num…
Alternative harmonic detection approach for quantitative determination of spin and orbital torques
Y. Xu, B. Bony, S. Krishnia +6
In this study, the spin-orbit torque (SOT) in light metal oxide systems is investigated using an experimental approach based on harmonic Hall voltage techniques in out-of-plane (OO…
A transmission electron microscope study of Néel skyrmion magnetic textures in multilayer thin film systems with large interfacial chiral interaction
S. McVitie, S. Hughes, K. Fallon +12
Skyrmions in ultrathin ferromagnetic metal (FM)/heavy metal (HM) multilayer systems produced by conventional sputtering methods have recently generated huge interest due to their a…
The puzzle of the soft X-ray excess in AGN: absorption or reflection?
L. Chevallier, S. Collin, A. -M. Dumont +4
The 2-10 keV continuum of AGN is generally well represented by a single power law. However, at smaller energies the continuum displays an excess with respect to the extrapolation o…
Quantifying the large contribution from orbital Rashba effect to the effective damping-like torque on magnetization
S. Krishnia, B. Bony, E. Rongione +10
The generation of large spin currents, and the associated spin torques, which are at the heart of modern spintronics, have long been achieved by charge-to-spin conversion mechanism…
Muon-induced background in the EDELWEISS dark matter search
The EDELWEISS collaboration, B. Schmidt, E. Armengaud +55
A dedicated analysis of the muon-induced background in the EDELWEISS dark matter search has been performed on a data set acquired in 2009 and 2010. The total muon flux underground…
Intermediate resolution H-beta spectroscopy and photometric monitoring of 3C 390.3 I. Further evidence of a nuclear accretion disk
A. I. Shapovalova, A. N. Burenkov, L. Carrasco +13
We have monitored the AGN 3C390.3 between 1995 and 2000.Two large amplitude outbursts, of different duration, in continuum and H beta light were observed ie.: in October 1994 a bri…
Long-term variability of the optical spectra of NGC 4151: I. Light curves and flux correlations
A. I. Shapovalova, L. C. Popovic, S. Collin +13
Results of a long-term spectral monitoring of the active galactic nucleus of NGC 4151 are presented (11 years, from 1996 to 2006). High quality spectra (S/N>50 in the continuum nea…
Chirality in magnetic multilayers probed by the symmetry and the amplitude of dichroism in X-ray resonant magnetic scattering
J. -Y. Chauleau, W. Legrand, N. Reyren +7
Chirality in condensed matter is now a topic of the utmost importance because of its significant role in the understanding and mastering of a large variety of new fundamental physi…
Effect of annealing on the superconducting properties of a-Nb(x)Si(1-x) thin films
O. Crauste, A. Gentils, F. Couëdo +5
a-Nb(x)Si(1-x) thin films with thicknesses down to 25 Ã have been structurally characterized by TEM (Transmission Electron Microscopy) measurements. As-deposited or annealed films…
A new high-background-rejection dark matter Ge cryogenic detector
A. Broniatowski, X. Defay, E. Armengaud +40
A new design of a cryogenic germanium detector for dark matter search is presented, taking advantage of the coplanar grid technique of event localisation for improved background di…
Accretion and Emission Processes in AGN: the UV-X Connection
S. Collin, A. Abrassart, B. Czerny +2
The main characteristics of the average spectrum of radio quiet AGN in the UV and X-ray range are reviewed, and the emission mechanisms are discussed in the framework of accretion…
Intensity and polarization of the atmospheric emission at millimetric wavelengths at Dome Concordia
E. S. Battistelli, G. Amico, A. Baù +32
Atmospheric emission is a dominant source of disturbance in ground-based astronomy at mm wavelengths. The Antarctic plateau is recognized to be an ideal site for mm and sub-mm obse…
Unconventional anomalous Hall effect in 3d/5d multilayers mediated by the nonlocal spin-conductivity
T. Huong Dang, Q. Barbedienne, Q. D. To +6
We evidenced unconventionnal Anomalous Hall Effects (AHE) in 3d/5d (Co0.2nm/Ni0.6nm)N multilayers grown on a thin Pt layer or thin Au:W alloy. The inversion observed on AHE origina…
Hot Carrier Solar Cells : In the Making ?
A. Le Bris, L. Lombez, Jean Francois Guillemoles +9
Hot carrier solar cells allow potential efficiency close to the thermodynamical limit in ideal conditions. However, the feasability of such devices has not been clearly stated so f…
A code for optically thick and hot photoionized media
A. -M. Dumont, A. Abrassart, S. Collin
We describe a code designed for hot media {(T } a few 10 K), optically thick to Compton scattering. It computes the structure of a plane-parallel slab of gas in thermal an…
First results of the EDELWEISS-II WIMP search using Ge cryogenic detectors with interleaved electrodes
E. Armengaud, C. Augier, A. Benoit +41
The EDELWEISS-II collaboration has performed a direct search for WIMP dark matter with an array of ten 400 g heat-and-ionization cryogenic detectors equipped with interleaved elect…
Thermal instability in X-ray photoionized media in Active Galactic Nuclei: Influence on the gas structure and spectral features
A. C. Goncalves, S. Collin, A. -M. Dumont +1
A photoionized gas in thermal equilibrium can display a thermal instability, with 3 or more solutions in the multi-branch region of the S-shape curve giving the temperature versus…
Long term variability of the Broad Emission Line profiles in AGN
A. I. Shapovalova, L. C. Popovic, N. G. Bochkarev +6
Results of a long-term monitoring ( years) of the broad line and continuum fluxes of three Active Galactic Nuclei (AGN), 3C 390.3, NGC 4151, and NGC 5548, are presented…
Quantitative analysis of vectorial torques in thin 3d Co ferromagnet using orbital-spin conversion
B. Bony, S. Krishnia, Y. Xu +6
Recent findings in orbitronics pointed out large current-induced torques originating, in the current understanding, from incident orbital currents. These are generated by orbital R…
Super-Eddington accretion rates in Narrow Line Seyfert 1 galaxies
S. Collin, Toshihiro Kawaguchi
Using the BH masses deduced from the empirical relation of Kaspi et al. (2000) and assuming that the optical luminosity is provided by the accretion disc, we show that Narrow Line…
Thermal instabilities in Active Galactic Nuclei: the case of thin vs. thick ionized media
A. C. Goncalves, S. Collin, A. -M. Dumont
We have studied the thermal instabilities in the context of Active Galactic Nuclei (AGN), addressing the cases of thin and thick (stratified) X-ray illuminated media. For that, we…
The Fe II problem in NLS1s
S. Collin, M. Joly
For more than twenty years, strong Fe II emission lines have been observed in Active Galactic Nuclei and in particular in Narrow Line Seyfert 1 galaxies. A quick overview of the ob…
Escape probability methods versus "exact" transfer for modelling the X-ray spectrum of Active Galactic Nuclei and X-ray binaries
A-M. Dumont, S. Collin, F. Paletou +3
In the era of XMM-Newton and Chandra missions, it is crucial to use codes able to compute correctly the line spectrum of X-ray irradiated thick media (Thomson thickness of the orde…
Strong Discontinuities in the Complex Photonic Band Structure of Transmission Metallic Gratings
S. Collin, F. Pardo, R. Teissier +1
Complex photonic band structures (CPBS) of transmission metallic gratings with rectangular slits are shown to exhibit strong discontinuities that are not evidenced in the usual ene…
X-ray holography of skyrmionic cocoons in aperiodic magnetic multilayers
M. Grelier, R. Battistelli, H. Popescu +9
The development and characterization of three-dimensional (3D) topological magnetic textures has become an important topic in modern magnetism both for fundamental and technologica…
Perpendicular magnetization reversal in Pt/[Co/Ni]/Al multilayers via the Spin Hall Effect of Pt
J. -C. Rojas-Sánchez, P. Laczkowski, J. Sampaio +6
We experimentally investigate the current-induced magnetization reversal in Pt/[Co/Ni]/Al multilayers combining the anomalous Hall effect and magneto-optical Kerr effect techni…
The structure and radiation spectra of illuminated accretion discs in AGN. I. Moderate illumination
A. RóżaÅska, A. -M. Dumont, B. Czerny +1
We present detailed computations of the vertical structure of an accretion disc illuminated by hard X-ray radiation with the code {\sc titan-noar} suitable for Compton thick media.…
Sensitivity of the EDELWEISS WIMP search to spin-dependent interactions
A. Benoit, L. Berge, J. Bluemer +35
The EDELWEISS collaboration is searching for WIMP dark matter using natural Ge cryogenic detectors. The whole data set of the first phase of the experiment contains a fiducial expo…
Monitoring of the thermal neutron flux in the LSM underground laboratory
S. Rozov, E. Armengaud, C. Augier +42
This paper describes precise measurements of the thermal neutron flux in the LSM underground laboratory in proximity of the EDELWEISS-II dark matter search experiment together with…
Tailored flux pinning in superconductor/ferromagnet multilayers with engineered magnetic domain morphology from stripes to skyrmions
X. Palermo, N. Reyren, S. Mesoraca +9
Superconductor/Ferromagnet (S/F) hybrid systems show interesting magneto-transport behaviors that result from the transfer of properties between both constituents. For instance, ma…
A detection system to measure muon-induced neutrons for direct Dark Matter searches
V. Yu. Kozlov, E. Armengaud, C. Augier +41
Muon-induced neutrons constitute a prominent background component in a number of low count rate experiments, namely direct searches for Dark Matter. In this work we describe a neut…
Measurement of the response of heat-and-ionization germanium detectors to nuclear recoils
A. Benoit, L. Berge, J. Blumer +34
The heat quenching factor Q' (the ratio of the heat signals produced by nuclear and electron recoils of equal energy) of the heat-and-ionization germanium bolometers used by the ED…
Profile variability of the H-alpha and H-beta broad emission lines in NGC5548
A. I. Shapovalova, V. T. Doroshenko, N. G. Bochkarev +10
Between 1996 and 2002, we have carried out a spectral monitoring program for the Seyfert galaxy NGC 5548. High quality spectra (S/N>50), covering the spectral range (4000-7500)AA w…
The XMM/BeppoSAX observation of Mkn 841
P. O. Petrucci, C. Cabanac, G. Henri +9
Mkn 841 has been observed simultaneously by XMM and BeppoSAX in January 2001. Due to operational contingency, the 30ks XMM observation was split into two parts, separated by about…
Models for the UV-X emission in AGN : influence of different parameters
S. Coupé, M-C. Artru, S. Collin +2
We present the results of computations performed with a new photoionisation-transfer code designed for hot Compton thick media. Presently the code solves the transfer of the contin…
Growth of massive black holes by super-Eddington accretion
T. Kawaguchi, K. Aoki, K. Ohta +1
Narrow-Line Seyfert 1 galaxies (NLS1s) and Narrow-Line quasars (NLQs) seem to amount to ~ 10-30 % of active galactic nuclei (AGNs) in the local universe. Together with their averag…
Mapping the radiative and the apparent non-radiative local density of states in the near field of a metallic nanoantenna
D. Cao, A. Cazé, M. Calabrese +6
We present a novel method to extract the various contributions to the photonic local density of states from near-field fluorescence maps. The approach is based on the simultaneous…
Large interfacial Rashba interaction and giant spin-orbit torques in atomically thin metallic heterostructures
S. Krishnia, Y. Sassi, F. Ajejas +6
The ability of spin-orbit interactions to convert charge current into spin current, most often in the bulk of heavy metal thin films, has been the hallmark of spintronics in the la…
A new model for the Warm Absorber in NGC 3783: a single medium in total pressure equilibrium
A. C. Goncalves, S. Collin, A. -M. Dumont +4
(Abridged) Many active galactic nuclei exhibit X-ray features typical of the highly ionized gas called "Warm Absorber" (WA). Such a material appears to be stratified, displaying zo…
Spintronic THz emitters based on transition metals and semi-metals/Pt multilayers
J. Hawecker, E. Rongione, A. Markou +11
Spintronic terahertz (THz) emitters (STE) based on the inverse spin Hall effect in ferromagnetic/heavy metal (FM/HM) heterostructures have become important sources for THz pulse ge…
Reprocessing of X-rays in AGN. I. Plane parallel geometry -- test of pressure equilibrium
A. -M. Dumont, B. Czerny, S. Collin +1
We present a model of the vertical stratification and the spectra of an irradiated medium under the assumption of constant pressure. Such a solution has properties intermediate bet…
X-ray emitting-absorbing media in Seyfert 1 galaxies
M. Mouchet, A. Abrassart, D. Porquet +2
Seyfert galaxies have been shown to exhibit a large variety of features in their X-ray spectra from which the environment of the central engine can be deduced. We focus on the two…
Quantitative imaging of hybrid chiral spin textures in magnetic multilayer systems by Lorentz microscopy
K. Fallon, S. McVitie, W. Legrand +5
Chiral magnetic textures in ultrathin perpendicularly magnetised multilayer film stacks with an interfacial Dzyaloshinskii-Moriya interaction have been the focus of much research r…
Orbital torque and efficient magnetization switching using ultrathin Co|Al light-metal interfaces: Experiments and modeling
N. Sebe, A. Pezo, S. Krishnia +5
The emergence of the orbital degree of freedom in modern orbitronics offers a promising alternative to heavy metals for the efficient control of magnetization. In this context, ide…
Final results of the EDELWEISS-I dark matter search with cryogenic heat-and-ionization Ge detectors
V. Sanglard, A. Benoit, L. Berge +40
The final results of the EDELWEISS-I dark matter search using cryogenic heat-and-ionization Ge detectors are presented. The final data sample corresponds to an increase by a factor…
Broadband and efficient diffraction
C. Ribot, M. S. L. Lee, S. Collin +6
Surface topography dictates the deterministic functionality of diffraction by a surface. In order to maximize the efficiency with which a diffractive optical component, such as a g…
Large enhancement of the spin Hall effect in Au by scattering with side-jump on Ta impurities
P. Laczkowski, Y. Fu, H. Yang +16
We present measurements of the Spin Hall Effect (SHE) in AuW and AuTa alloys for a large range of W or Ta concentrations by combining experiments on lateral spin valves and Ferroma…
Tunable Superconducting Properties of a-NbSi Thin Films and Application to Detection in Astrophysics
O. Crauste, C. A. Marrache-Kikuchi, L. Berge +5
We report on the superconducting properties of amorphous NbxSi1-x thin films. The normal-state resistance and critical temperatures can be separately adjusted to suit the desired a…
A rapidly variable narrow X-ray iron line in Mkn 841
P. O. Petrucci, G. Henri, L. Maraschi +8
We report on the detection of a rapidly variable narrow Fe K line in Mkn 841. The source has been observed two times by XMM-Newton and simultaneously with BeppoSAX. The two obs…
Evolution of the X-ray spectrum in the flare model of Active Galactic Nuclei
S. Collin, S. Coupé, A-M. Dumont +2
Nayakshin & Kazanas (2002) have considered the time-dependent illumination of an accretion disc in Active Galactic Nuclei, in the lamppost model. We extend their study to the flare…
QUBIC: The QU Bolometric Interferometer for Cosmology
The QUBIC collaboration, E. Battistelli, A. Baù +57
One of the major challenges of modern cosmology is the detection of B-mode polarization anisotropies in the CMB. These originate from tensor fluctuations of the metric produced dur…
Ultrafast spin-currents and charge conversion at 3d-5d interfaces probed by time-domain terahertz spectroscopy
T. H. Dang, J. Hawecker, E. Rongione +21
Spintronic structures are extensively investigated for their spin orbit torque properties, required for magnetic commutation functionalities. Current progress in these materials is…