M. Gros

Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic clouds

The EROS-2 project was designed to test the hypothesis that massive compact halo objects (the so-called machos) could be a major component of the dark matter halo of the Milky Way galaxy. To this end, EROS-2 monitored millions of stars in the Magellanic clouds for microlensing events caused by such objects. (abridged)

Limits on Galactic dark matter with 5 years of EROS SMC data

Five years of EROS data towards the Small Magellanic Cloud have been searched for gravitational microlensing events, using a new, more accurate method to assess the impact of stellar blending on the efficiency. Four long-duration candidates have been found which, if they are microlensing events, hint at a non-halo population of lenses. Combined with results from other EROS observation programs, this analysis yields strong limits on the amount of Galactic dark matter made of compact objects. Less than 25% of a standard halo can be composed of objects with a mass between 2 10^-7 Msol and 1 Msol at the 95% C.L.

Galactic Bulge microlensing optical depth from EROS-2

We present a new EROS-2 measurement of the microlensing optical depth toward the Galactic Bulge. Light curves of

Properties of the energetic particle distributions during the October 28, 2003 solar flare from INTEGRAL/SPI observations

5.6times 10^{6}

Type Ia supernova rate at a redshift of ~;0.1

clump-giant stars distributed over

Bulge microlensing optical depth from EROS 2 observations

66 deg^2

INTEGRAL/SPI ground calibration

of the Bulge were monitored during seven Bulge seasons. 120 events were found with apparent amplifications greater than 1.6 and Einstein radius crossing times in the range

First identification and modelling of SPI background lines

5 {rm d}

SPI instrumental background characteristics

Analysis of spectra obtained with the gamma-ray spectrometer SPI onboard INTEGRAL of the GOES X17-class flare on October 28, 2003 is presented. In the energy range 600 keV - 8 MeV three prominent narrow lines at 2.223, 4.4 and 6.1 MeV, resulting from nuclear interactions of accelerated ions within the solar atmosphere could be observed. Time profiles of the three lines and the underlying continuum indicate distinct phases with several emission peaks and varying continuum-to-line ratio for several minutes before a smoother decay phase sets in. Due to the high-resolution Ge detectors of SPI and the exceptional intensity of the flare, detailed studies of the 4.4 and 6.1 MeV line shapes was possible for the first time. Comparison with calculated line shapes using a thick target interaction model and several energetic particle angular distributions indicates that the nuclear interactions were induced by downward-directed particle beams with alpha-to-proton ratios of the order of 0.1. There are also indications that the 4.4 MeV to 6.1 MeV line fluence ratio changed between the beginning and the decay phase of the flare, possibly due to a temporal evolution of the energetic particle alpha-to-proton ratio.

New Magellanic Cloud R Coronae Borealis and DY Persei type stars from the EROS-2 database: the connection between RCBs, DYPers, and ordinary carbon stars

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