Martine Mouchet

Type Ia supernova rate at a redshift of ~;0.1

Astronomy & Astrophysics manuscript no. rate (DOI: will be inserted by hand later) May 12, 2004 Type Ia supernova rate at a redshift of ∼ 0.1 G. Blanc 1,12,22 , C. Afonso 1,4,8,23 , C. Alard 24 , J.N. Albert 2 , G. Aldering 15,28 , A. Amadon 1 , J. Andersen 6 , R. Ansari 2 , E. Aubourg 1 , C. Balland 13,21 , P. Bareyre 1,4 , J.P. Beaulieu 5 , X. Charlot 1 , A. Conley 15,28 , 1 , T. Dahl´ n 19 , F. Derue 13 , X. Fan 16 , R. Ferlet 5 , G. Folatelli 11 , P. Fouqu´ 9,10 , G. Garavini 11 , C. Coutures e e J.F. Glicenstein 1 , B. Goldman 1,4,8,23 , A. Goobar 11 , A. Gould 1,7 , D. Graff 7 , M. Gros 1 , J. Haissinski 2 , C. Hamadache 1 , D. Hardin 13 , I.M. Hook 25 , J. de Kat 1 , S. Kent 18 , A. Kim 15 , T. Lasserre 1 , L. Le Guillou 1 , E. Lesquoy 1,5 , C. Loup 5 , C. Magneville 1 , J.B. Marquette 5 , E. Maurice 3 , A. Maury 9 , A. Milsztajn 1 , M. Moniez 2 , M. Mouchet 20,22 , H. Newberg 17 , S. Nobili 11 , N. Palanque-Delabrouille 1 , O. Perdereau 2 , L. Pr´ vot 3 , Y.R. Rahal 2 , N. Regnault 2,14,15 , J. Rich 1 , P. Ruiz-Lapuente 27 , M. Spiro 1 , P. Tisserand 1 , e A. Vidal-Madjar 5 , L. Vigroux 1 , N.A. Walton 26 , S. Zylberajch 1 . arXiv:astro-ph/0405211 v1 11 May 2004 DSM/DAPNIA, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France Laboratoire de l’Acc´ l´ rateur Lin´ aire, IN2P3 CNRS, Universit´ Paris-Sud, 91405 Orsay Cedex, France e e e e Observatoire de Marseille, 2 pl. Le Verrier, 13248 Marseille Cedex 04, France Coll` ge de France, Physique Corpusculaire et Cosmologie, IN2P3 CNRS, 11 pl. M. Berthelot, 75231 Paris e Cedex, France Institut d’Astrophysique de Paris, INSU CNRS, 98 bis Boulevard Arago, 75014 Paris, France Astronomical Observatory, Copenhagen University, Juliane Maries Vej 30, 2100 Copenhagen, Denmark Departments of Astronomy and Physics, Ohio State University, Columbus, OH 43210, U.S.A. Department of Astronomy, New Mexico State University, Las Cruces, NM 88003-8001, U.S.A. European Southern Observatory (ESO), Casilla 19001, Santiago 19, Chile Observatoire Midi-Pyr´ n´ es, 14 avenue Edouard Belin, 31400 Toulouse, France e e Department of Physics, Stockholm University, AlbaNova University Center, S-106 91 Stockholm, Sweden Osservatorio Astronomico di Padova, INAF, vicolo dell’Osservatorio 5 - 35122 Padova, Italy Laboratoire de Physique Nucl´ aire et de Hautes Energies, IN2P3 - CNRS - Universit´ s Paris 6 et Paris 7, 4 e e place Jussieu, 75252 Paris Cedex 05, France Laboratoire Leprince-Ringuet, LLR/Ecole Polytechnique, Route de Saclay, 91128 Palaiseau CEDEX, France Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720, U.S.A. Steward Observatory, The University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721-0065, U.S.A. Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180, U.S.A. Fermilab Wilson and Kirk Roads, Batavia, IL 60510-0500, U.S.A. Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, U.S.A. LUTH, Observatoire de Paris, 5, Place Jules Janssen, 92195 Meudon Cedex, France Institut d’Astrophysique Spatiale, Bˆ timent 121, Universit´ Paris 11, 91405 Orsay Cedex, France a e Universit´ Paris 7 Denis Diderot, 2, place Jussieu, 75005 Paris, France e NASA/Ames Research Center, Mail Stop 244, Moffet Field, CA 94035, U.S.A. GEPI, Observatoire de Paris, 77 avenue de l’Observatoire, 75014 Paris, France Department of Physics, University of Oxford, Nuclear and Astrophysics laboratory, Keble Road, Oxford OX1 3RH, UK Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK Department of Astronomy, University of Barcelona, Barcelona, Spain Visiting astronomer, Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatories, which are operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation. Received / Accepted Abstract. We present the type Ia rate measurement based on two EROS supernova search campaigns (in 1999 and 2000). Sixteen supernovae identified as type Ia were discovered. The measurement of the detection efficiency, using a Monte Carlo simulation, provides the type Ia supernova explosion rate at a redshift ∼ 0.13. The result is 0.125 +0.044+0.028 h 2 SNu where 1 SNu = 1 SN / 10 10 L B / century. This value is compatible with the previous EROS measurement (Hardin et al. 2000), done with a much smaller sample, at a similar redshift. Comparison with other values at different redshifts suggests an evolution of the type Ia supernova rate. Key words. (Stars:) supernovae: general – Galaxies: evolution

Two new intermediate polars with a soft X-ray component

Aims. We analyze the first X-ray observations with XMM-Newton of 1RXS J070407.9+262501 and 1RXS 180340.0+401214, in order to characterize their broad-band temporal and spectral properties, also in the UV/optical domain, and to confirm them as intermediate polars. Methods. For both objects, we performed a timing analysis of the X-ray and UV/optical light curves to detect the white dwarf spin pulsations and study their energy dependence. For 1RXS 180340.0+401214 we also analyzed optical spectroscopic data to determine the orbital period. X-ray spectra were analyzed in the 0.2–10.0 keV range to characterize the emission properties of both sources. Results. We find that the X-ray light curves of both systems are energy dependent and are dominated, below 3–5 keV, by strong pulsations at the white dwarf rotational periods (480 s for 1RXS J070407.9+262501 and 1520.5 s for 1RXS 180340.0+401214). In 1RXS 180340.0+401214 we also detect an X-ray beat variability at 1697 s which, together with our new optical spectroscopy, favours an orbital period of 4.4 h that is longer than previously estimated. Both systems show complex spectra with a hard (temperature up to 40 keV) optically thin and a soft (kT ∼ 85–100 eV) optically thick components heavily absorbed by material partially covering the X-ray sources. Conclusions. Our observations confirm the two systems as intermediate polars and also add them as new members of the growing group of “soft” systems which show the presence of a soft X-ray blackbody component. Differences in the temperatures of the blackbodies are qualitatively explained in terms of reprocessing over different sizes of the white dwarf spot. We suggest that systems showing cooler soft X-ray blackbody components also possess white dwarfs irradiated by cyclotron radiation.

Unveiling the broad band X-ray continuum and iron line complex in Mkr 841

Mkr 841 is a bright Seyfert 1 galaxy known to harbor a strong soft excess and a variable K

High-resolution X-ray spectroscopy of the Seyfert 1 Mrk 841: insights into the warm absorber and warm emitter

\alpha

Iron lines from transient and persisting hot spots on AGN accretion disks

iron line. It has been observed during 3 different periods by XMM for a total cumulated exposure time of

Full radiative coupling in two-phase models for accreting black holes

\sim

The surprising Far-UV spectrum of the polar BY Camelopardalis

108 ks. We present in this paper a broad band spectral analysis of the complete EPIC-pn data sets. We were able to test two different models for the soft excess, a relativistically blurred photoionized reflection (\r model) and a relativistically smeared ionized absorption (\a model). The continuum is modeled by a simple cut-off power law and we also add a neutral reflection. These observations reveal the extreme and puzzling spectral and temporal behaviors of the soft excess and iron line. The 0.5-3 keV soft X-ray flux decreases by a factor 3 between 2001 and 2005 and the line shape appears to be a mixture of broad and narrow components. We succeed in describing this complex broad-band 0.5-10 keV spectral variability using either \r or \a to fit the soft excess. Both models give statistically equivalent results even including simultaneous BeppoSAX data up to 200 keV. Both models are consistent with the presence of remote reflection characterized by a constant narrow component in the data. However they differ in the presence of a broad line component present in \r but not needed in \a. This study also reveals the sporadic presence of relativistically redshifted narrow iron lines.

Numerical simulations of high-energy flows in accreting magnetic white dwarfs

Context. The Seyfert 1 galaxy Mrk 841 was observed five times between 2001 and 2005 by the XMM-Newton X-ray observatory. The source is well known for showing spectral complexity in the variable iron line and in the soft X-ray excess. Aims. The availability of multiple exposures obtained by the reflection grating spectrometer (RGS) cameras allows thorough study of the complex absorption and emission spectral features in the soft X-ray band. This paper reports on the first study of Mrk 841 soft X-ray spectrum at high spectral resolution. Methods. The three combined exposures obtained in January 2001 and the two obtained in January and July 2005 were analysed with the SPEX software. Results. We detect a two-phase warm absorber. A medium ionisation component (log ξ ∼ 1.5−2. 2e rg sc m −1 ) is responsible for a deep absorption feature in the unresolved transition array of the Fe M-shell and for several absorption lines in the OVI-VIII band, and a higher ionisation phase with log ξ ∼ 3e rg s cm −1 is required to fit absorption in the NeIX-X band. The ionisation state and the column density of the gas present moderate variation from 2001 to 2005 for both phases. The high ionisation component of the warm absorber has no effect on the Fe K band. No significant velocity shift of the absorption lines is measured in the RGS data. Remarkably, the 2005 spectra show emission features consistent with photoionisation in a high-density (ne ≥ 10 11 cm −3 ) gas. A prominent OVII line triplet was clearly observed in January 2005 and narrow radiative recombination continua (RRC) of OVII and CVI were observed in both 2005 data sets. A broad Gaussian line around 21.7 A was also required to fit all the data sets. The derived radial distance for the emission lines seems to suggest that the photoionisation takes place within the optical broad line region of the source.

The SNLS-VLT Type Ia Spectrum Evolution with Redshift: a Demographic Effect?

Aims. We model the X-ray reprocessing from a strong co-rotating flare above an accretion disk in active galactic nuclei. By performing detailed radiative transfer computations we explore the horizontal structure and evolution of the underlying hot spot. The main goal is to study how the resulting spectral features manifest themselves in short exposure time spectra. Methods. We analyze both the vertical and the horizontal spot structure and its dynamical reprocessed spectrum. To obtain the spectral evolution seen by a distant observer, we apply a general relativity ray-tracing technique. We concentrate on the energy band around the iron K-line, where the relativistic effects are most pronounced. Persistent flares lasting for a significant fraction of the orbital time scale and short, transient flares are considered. Results. In our time-resolved analysis, the spectra recorded by a distant observer depend on the position of the flare/spot with respect to the central black hole. If the flare duration significantly exceeds the light travel time across the spot, then the spot horizontal stratification is unimportant. On the other hand, if the flare duration is comparable to the light travel time across the spot radius, the lightcurves exhibit a typical asymmetry in their time profiles. The sequence of dynamical spectra proceeds from more strongly to less strongly ionized re-emission. At all locations within the spot the spectral intensity increases towards edge-on emission angles, revealing the limb brightening effect. Conclusions. Future X-ray observatories with significantly larger effective collecting areas will enable to spectroscopically map out the azimuthal irradiation structure of the accretion disk and to localize persistent flares. If the hot spot is not located too close to the marginally stable orbit of the black hole, it will be possible to probe the reflecting medium via the sub-structure of the iron K-line. Indications for transient flares will only be obtained from analyzing the observed lightcurves on the gravitational time scale of the accreting supermassive black hole.

Magnetic Accreting White Dwarfs in the XMM‐Newton Era

The emission from galactic black holes and Seyfert galaxies is generally understood in term of two-phase models (Haardt & Maraschi 1991, 1993). Such models postulate that a hot plasma (∼10 9 K) coexists with relatively colder material (∼10 6 K) in the inner part of the accretion flow. We present the first simulated broad-band spectra produced by such a system and accounting simultaneously for energy balance and Comptonisation in the hot phase, together with reflection, reprocessing, ionization and thermal balance in the cold phase. This was made possible by coupling three radiative transfer codes: a non- linear Monte-Carlo code (NLMC), a photo-ionization code TITAN and a linear Monte-Carlo code NOAR. The equilibrium comptonisation spectrum appears to be sensitive to the shape of the reprocessed spectrum that, in turn, depends on the ionization parameter, but also on the structure of the irradiated cold material. This is illustrated by a comparison of simulations assuming constant density or a constant pressure in the cold phase. We also compare our results with simplified models where reprocessing is approximated by a blackbody spectrum. Our detailed treatment leads to noticeably different spectral energy distributions (SEDs) characterised by harder X-ray spectra. Even at low ionization parameters (ξ ∼ 300 erg s −1 cm) the commonly used blackbody approximation is poor, leading to X-ray spectra that are too soft. The effect, however, seems not to be strong enough to reconcile the slab corona model with the hardest observed spectra, unless the reflector has a constant density and the ionization parameter is large, of the order of 10 4 erg s −1 cm.