Distribution of the heavy elements throughout the extended narrow line region of the Seyfert galaxy NGC 7212

The latest observations of line and continuum spectra emitted from the extended narrow line region (ENLR) of the Seyfert 2 galaxy NGC 7212 are analysed using models accounting for photoionization from the active nucleus and shocks. The results show that relatively high (500--800 \kms) shock velocities appear on the edge of the cone and outside of it. The model-inferred AGN flux, which is lower than $10^{-11}$ photons cm$^{-2}$ s$^{-1}$ eV$^{-1}$ at the Lyman limit, is more typical of low-luminosity AGN, and less so for Seyfert 2 galaxies. The preshock densities are characteristic of the ENLR and range between 80--150 cm$^{-3}$. Nitrogen and sulphur are found depleted by a factor lower than 2, particularly at the eastern edge. Oxygen is depleted at several locations. The Fe/H ratio is approximately solar, whereas the Ne/H relative abundance is unusually high, 1.5--2 times the solar value. Modelling the continuum spectral energy distribution (SED), we have found radio synchrotron radiation generated by the Fermi mechanism at the shock front, whereas the X-rays are produced by the bremsstrahlung from a relatively high temperature plasma.Comment: 17 pages, 14 figures, accepted for publication in A&

A Multi-Cloud Warm-Absorber Model for NGC 4051

A multi-cloud model is presented which explains the soft X-ray excess in NGC 4051 and, consistently, the optical line spectrum and the SED of the continuum. The clouds are heated and ionized by the photoionizing flux from the active center and by shocks. Diffuse radiation, partly absorbed throughout the clouds, nicely fits the bump in the soft X-ray domain, while bremsstrahlung radiation from the gaseous clouds contribute to the fit of the continuum SED. Debris of high density fragmented clouds are necessary to explain the absorption oxygen throats observed at 0.87 keV and 0.74 keV. The debris are heated by shocks of about 200-300 km/s. Low velocity (100 km/s)-density (100 cm-3) clouds contribute to the line and continuum spectra, as well as high velocity (1000 km/s)-density (8000 cm-3) clouds which are revealed by the FWHM of the line profiles. The SED in the IR is explained by reradiation of dust, however, the dust-to-gas ratio is not particularly high. Radio emission is well fitted by synchrotron radiation created at the shock front by Fermi mechanism.Comment: 19 pages + 3 figures PostScrip

A study on the multicolour evolution of Red Sequence galaxy populations: insights from hydrodynamical simulations and semi-analytical models

By means of our own cosmological-hydrodynamical simulation and semi-analytical model we studied galaxy population properties in clusters and groups, spanning over 10 different bands from UV to NIR, and their evolution since redshift z=2. We compare our results in terms of galaxy red/blue fractions and luminous-to-faint ratio (LFR) on the Red Sequence (RS) with recent observational data reaching beyond z=1.5. Different selection criteria were tested in order to retrieve galaxies belonging to the RS: either by their quiescence degree measured from their specific SFR ("Dead Sequence"), or by their position in a colour-colour plane which is also a function of sSFR. In both cases, the colour cut and the limiting magnitude threshold were let evolving with redshift, in order to follow the natural shift of the characteristic luminosity in the LF. We find that the Butcher-Oemler effect is wavelength-dependent, with the fraction of blue galaxies increasing steeper in optical colours than in NIR. Besides, only when applying a lower limit in terms of fixed absolute magnitude, a steep BO effect can be reproduced, while the blue fraction results less evolving when selecting samples by stellar mass or an evolving magnitude limit. We then find that also the RS-LFR behaviour, highly debated in the literature, is strongly dependent on the galaxy selection function: in particular its very mild evolution recovered when measured in terms of stellar mass, is in agreement with values reported for some of the highest redshift confirmed (proto)clusters. As to differences through environments, we find that normal groups and (to a lesser extent) cluster outskirts present the highest values of both star forming fraction and LFR at low z, while fossil groups and cluster cores the lowest: this separation among groups begins after z~0.5, while earlier all group star forming properties are undistinguishable.Comment: revised version, A&A accepted (11 pages, 6 figures

Evolution of the mass, size, and star formation rate in high-redshift merging galaxies MIRAGE - A new sample of simulations with detailed stellar feedback

We aim at addressing the questions related to galaxy mass assembly through major and minor wet merging processes in the redshift range 1<z<2. A consequent fraction of Milky Way like galaxies are thought to have undergone an unstable clumpy phase at this early stage. Using the adaptive mesh refinement code RAMSES, with a recent physically-motivated implementation of stellar feedback, we build the Merging and Isolated high-Redshift Adaptive mesh refinement Galaxies (MIRAGE) sample. It is composed of 20 mergers and 3 isolated idealized disks simulations with global physical properties in accordance with the 1<z<2 mass complete sample MASSIV. The numerical hydrodynamical resolution reaches 7 parsecs in the smallest Eulerian cells. Our simulations include: star formation, metal line cooling, metallicity advection, and a recent implementation of stellar feedback which encompasses OB-type stars radiative pressure, photo-ionization heating, and supernovae. The initial conditions are set to match the z~2 observations, thanks to a new public code DICE. The numerical resolution allows us to follow the formation and evolution of giant clumps formed in-situ from Jeans instabilities triggered by high initial gas fraction. The star formation history of isolated disks shows stochastic star formation rate, which proceeds from the complex behavior of the giant clumps. Our minor and major gas-rich merger simulations do not trigger starbursts, suggesting a saturation of the star formation in a turbulent and clumpy interstellar medium fed by substantial accretion from the circum-galactic medium. Our simulations are close to the normal regime of the disk-like star formation on a Schmidt-Kennicutt diagram. The mass-size relation and its rate of evolution matches observations, suggesting that the inside-out growth mechanisms of the stellar disk do not necessarily require to be achieved through a cold accretion.Comment: 18 pages, 12 figures. Accepted in A&

High resolution spectroscopy of the extended narrow-line region of IC 5063 and NGC 7212

We studied the properties of the gas of the extended narrow line region (ENLR) of two Seyfert 2 galaxies: IC 5063 and NGC 7212. We analysed high resolution spectra to investigate how the main properties of this region depend on the gas velocity. We divided the emission lines in velocity bins and we calculated several line ratios. Diagnostic diagrams and SUMA composite models (photo-ionization + shocks), show that in both galaxies there might be evidence of shocks significantly contributing in the gas ionization at high |V|, even though photo-ionization from the active nucleus remains the main ionization mechanism. In IC 5063 the ionization parameter depends on V and its trend might be explained assuming an hollow bi-conical shape for the ENLR, with one of the edges aligned with the galaxy disk. On the other hand, NGC 7212 does not show any kind of dependence. The models show that solar O/H relative abundances reproduce the observed spectra in all the analysed regions. They also revealed an high fragmentation of the gas clouds, suggesting that the complex kinematics observed in these two objects might be caused by interaction between the ISM and high velocity components, such as jets.Comment: 29 pages, 32 figures, accepted for publication in MNRA

Modeling RR Tel through the Evolution of the Spectra

We investigate the evolution of RR Tel after the outburst by fitting the emission spectra in two epochs. The first one (1978) is characterized by large fluctuations in the light curve and the second one (1993) by the slow fading trend. In the frame of a colliding wind model two shocks are present: the reverse shock propagates in the direction of the white dwarf and the other one expands towards or beyond the giant. The results of our modeling show that in 1993 the expanding shock has overcome the system and is propagating in the nearby ISM. The large fluctuations observed in the 1978 light curve result from line intensity rather than from continuum variation. These variations are explained by fragmentation of matter at the time of head-on collision of the winds from the two stars. A high velocity (500 km/s) wind component is revealed from the fit of the SED of the continuum in the X-ray range in 1978, but is quite unobservable in the line profiles. The geometrical thickness of the emitting clumps is the critical parameter which can explain the short time scale variabilities of the spectrum and the trend of slow line intensity decrease.Comment: 26 pages, LaTeX (including 5 Tables) + 6 PostScript figures. To appear in "The Astrophysical Journal

IEC 61508: Effect of test policy on the probability of failure on demand of safety instrumented systems

Standard IEC 61508 provides probabilistic equations for determining the Average Probability of Failure on Demand (PFDavg) and the Average Probability of Failure per Hour (PFHavg) for some architectures of Safety Instrumented Systems (SIS) under the hypothesis of equal redundant components, taking into account Common Cause Failures (CCF), Detection Coverage (DC) and Proof Test Coverage (PTC) parameters. Surprisingly, IEC standard does not mention the testing policy aspects of SIS redundant components. However, from a close examination of the probabilistic equations, it is possible to recognize that the simultaneous/sequential testing policy has been implicitly assumed. This paper describes the conditions under which the staggered testing policy - which is better than all the others in case of independent tested components - can be advantageously applied to reduce PFDavg when CCF, DC and PTC parameters are taken into account

Estimation du DFG en oncopédiatrie : clairance au 51CR-EDTA vs clairance à la créatinine par méthode Jaffé et enzymatique

National audienceObjectifs.– Étudier la possibilité de suivre la fonction rénale chez des patients depédiatrie sous chimiothérapie uniquement par l’estimation du DFG au moyende la clairance à la créatinine (eDFG), méthode plus simple et déjà utilisée enclinique pour le suivi de l’insuffisance rénale chronique chez l’adulte. Le mDFG(un desgold standard) a été comparé séparément aux eDFG obtenus avec uneméthode de Jaffé (MJ) et au eDFG obtenu avec une méthode enzymatique (ME).Matériels et méthodes.– L’étude a été réalisée par recueil rétrospectif sur93 patients (cinq mois–21 ans) de janvier 2007 à septembre 2012. La clai-rance au51Cr-EDTA (n= 181) a été calculée à partir d’une méthode à quatrepoints (correction de Brochner–Mortensen 2009) et les clairances à la créati-nine ont été estimées par la formule de Schwartz (127 en MJ et 54 en ME).Le mDFG a été comparé aux eDFG obtenus par MJ et ME par un test sta-tistique de Student pour séries appariées. La concordance entre les méthodesa été évaluée graphiquement par la méthode de Bland et Altman, le biais(erreur systématique), les précisions à 30 % et 10 % ont aussi été calcu-lés. Enfin, les méthodes ont été comparées lors d’un suivi longitudinal sur26 patients.Résultats.– Le test de Student met en évidence une différence significative deseDFG avec le mDFG (p< 0,001 avec MJ et ME ;= 0,05). L’étude de Blandet Altman révèle d’une part des biais moyen (moyenne des différences entresles deux méthodes) important de 81 mL/min/1,73 m2pour MJ et modéré de16 mL/min/1,73 m2pour ME, soit respectivement une surestimation moyennede 80 % et 17 % en faveur du eDFG, et d’autre part des écart-types importantégal à 50 mL/min/1,73m2pour MJ et 33 mL/min/1,73m2pour ME. Les préci-sions à 30 % et 10 % sont respectivement très faibles (11 % et 2 %) pour MJ etmodérée (75 % et 33 %) pour ME. Le suivi longitudinal met en évidence desdivergences critiques de résultats (stabilité, élévation, diminution du DFG) entremDFG et eDFG.Conclusions.– L’ensemble des résultats obtenus permet de conclure à la non-transposabilité des méthodes et d’exclure l’utilisation du eDFG pour suivre lafonction rénale des patients d’oncologie pédiatrique en routine clinique

New Wolf-Rayet Galaxies with Detection of WC Stars

We report the discovery of two new Wolf-Rayet (WR) galaxies: Mrk~1039, and F08208$+$2816. Two broad WR bumps at 5808\AA~ and 4650\AA~ indicate the presence of WCE and WNL star population in all two sources. We also confirm the presenceof WR features in Mrk~35, previously detected in a different position. The observed equivalent width of the WR bump at 4650\AA~ and the derived number ratios of WR/(WR$+$O) imply that star formation in these sources takes place inshort burst duration. Comparisons with the recent models of WR populations in young starbursts with the observed EW(\HeII)/EW(\CIV)/EW(WRbump) and their relative intensitie provide an indication that the stellar initial mass function in some WR galaxies might not be Salpeter-like. It is interesting to find that the luminous IRAS source, F08208$+$2816, has little dust reddening, probably because of the existence of a powerful superwind. By comparisons with other starbursts observed with the Hopkins Ultraviolet Telescope, F08208$+$2816 as a merging system renders a chance to study the contribution from young starbursts to the UV background radiation in universe.Comment: 22 pages, 6 figures, 4 tables, accepted by The Astrophysical Journa