1. Abell 611. II. X-ray and strong lensing analyses [pdf, ps, other]
  2. 21 pages, 16 figures; submitted to Astronomy and Astrophysics
  3. A search for galaxies in and around an HI overdense region at z=5[pdf, ps, other]
  4. Y. Matsuda (1), J. Richard (1), Ian Smail (1), N. Kashikawa (2), K. Shimasaku (3), B. L. Frye (4), T. Yamada (5), Y. Nakamura (5), T. Hayashino (5), T. Fujii (5) ((1) Durham, (2) NAOJ, (3) Tokyo, (4) USF, (5) Tohoku)
    6 pages, 4 figures, accepted for publication in MNRAS
  5. The dark matter of gravitational lensing[pdf, ps, other]
  6. 47 page review. Submitted to Rep.Prog.Phys. and incorporating suggestions from one referee. Comments welcome!
  7. Gas, dust and stars in the SCUBA galaxy, SMM J02399-0136: the EVLA reveals a colossal galactic nursery [pdf, ps, other]
  8. in press at MNRAS; 8 pages; 4 figures, 3 in colour
  9. MACSJ1423.8+2404: Gravitational Lensing by a Massive, Relaxed Clus ter of Galaxies at z=0.54[pdf, other]
  10. Accepted for publication in MNRAS. High resolution available at this http URL
  11. LoCuSS: First Results from Strong-lensing Analysis of 20 Massive G alaxy Clusters at z~0.2[pdf, ps, other]
  12. Johan Richard (Durham), Graham P. Smith (Birmingham), Jean-Paul Kneib (Marseille), Richard Ellis (Caltech), Alastair J. R. Sanderson (Birmingham), Liuyi Pei (Caltech), Thomas Targett (UBC), David Sand (Harvard), Mark Swinbank (Durham), Helmut Dannerbauer (Heidelberg), Pasquale Mazzotta (Roma), Marceau Limousin (Marseille), Eiichi Egami (Tucson), Eric Jullo (JPL), Victoria Hamilton-Morris (Birmingham), Sean Moran (Johan Hopkins)
    28 pages, 14 figures, accepted for publication in MNRAS, replaced with accepted version
  13. Physical properties and morphology of a newly identified compact z =4.04 lensed submillimeter galaxy in Abell 2218[pdf, ps, other]
  14. K.K. Knudsen (AIfA, Bonn), J.-P. Kneib (OAMP), J. Richard (Durham), G. Petitpas (CfA), E. Egami (Arizona)
    Accepted for publication in ApJ. 11 pages, 7 figures
  15. Hubble Space Telescope Observations of a Spectacular New Strong-le nsing Galaxy Cluster - MACSJ1149.5+2223 at z=0.544[pdf, ps, other]
  16. Accepted by ApJL; 6 pages, 4 figures; a version with figure 1 at full resolution is available at this http URL
  17. Abell 370 revisited: refurbished Hubble imaging of the first stron g lensing cluster [pdf, ps, other]
  18. Johan Richard (Durham), Jean-Paul Kneib (OAMP), Marceau Limousin (OAMP, Dark Cosmology Centre), Alastair Edge (Durham), Eric Jullo (JPL)
    6 pages, 2 figures, accepted to MNRAS letters, replaced with accepted version
  19. Looking for the first galaxies: Lensing or blank fields?[pdf, ps, other]
  20. A. Maizy (LATT), J. Richard (Durham), M. A. De Leo (UNAM), R. Pello (LATT), J. P. Kneib (LAM)
    17 pages, 13 figures, accepted for publication in A&A
  21. Resolved Spectroscopy of Gravitationally-Lensed Galaxies: Recoveri ng Coherent Velocity Fields in Sub-Luminous z~2-3 Galaxies [pdf, ps, other]
  22. 18 pages, 8 figures, submitted to MNRAS
  23. The Distribution of Dark Matter Over 3 Decades in Radius in the Le nsing Cluster Abell 611[pdf, ps, other]
  24. A. B. Newman (1), T. Treu (2), R. S. Ellis (1), D. J. Sand (3,4), J. Richard (5), P. J. Marshall (2), P. Capak (6), S. Miyazaki (7) ((1) Caltech, (2) U. C. Santa Barbara, (3) Harvard-Smithsonian CfA, (4) Las Cumbres Observatory, (5) Univ. of Durham, (6) Spitzer Science Center, (7) NAOJ)
    Accepted to ApJ, 18 pages, 13 figures
  25. A Spatially Resolved Map of the Kinematics, Star-Formation and Ste llar Mass Assembly in a Star-Forming Galaxy at z=4.9 [pdf, ps, other]
  26. Mark Swinbank (1), Tracy Webb (2), Johan Richard (1), Richard Bower (1) Richard Ellis (3), Garth Illingworth (4), Tucker Jones (3), Mariska Kriek (5), Ian Smail (1), Dan Stark (6), Pieter Van Dokkum (7) ((1) Durham, (2) McGill, (3) Caltech, (4) UCSC, (5) Princeton, (6) Cambridge, (7) Yale)
    Accepted for publication in MNRAS. 11 pages, 7 figures
  27. Near-IR search for lensed supernovae behind galaxy clusters: I. O bservations and transient detection efficiency[pdf, ps, other]
  28. Language-edited version, 9 pages, 6 figures, accepted by A&A
  29. LoCuSS: A Comparison of Sunyaev-Zel'dovich Effect and Gravita tional Lensing Measurements of Galaxy Clusters[pdf, ps, other]
  30. Daniel P. Marrone (1 and 2), Graham P. Smith (3), Johan Richard (4 and 5), Marshall Joy (6), Massimiliano Bonamente (7), Nicole Hasler (7), Victoria Hamilton-Morris (3), Jean-Paul Kneib (8), Thomas Culverhouse (1), John E. Carlstrom (1), Christopher Greer (1), David Hawkins (4), Ryan Hennessy (1), James W. Lamb (4), Erik M. Leitch (1), Michael Loh (1), Amber Miller (9), Tony Mroczkowski (9), Stephen Muchovej (4 and 9), Clem Pryke (1), Matthew K. Sharp (1), David Woody (4) ((1) UChicago/KICP, (2) NRAO, (3) University of Birmingham, (4) Caltech, (5) Durham University, (6) NASA MSFC, (7) University of Alabama, Huntsville, (8) LAM OAMP, (9) Columbia)
    Minor changes to match published version: 2009 ApJL 701:114-118
    Journal-ref: Astrophys.J.701:L114-L118,2009
  31. Strong Lensing as a Probe of the Mass Distribution Beyond the Eins tein Radius. Mass & Light in SL2S J0544-0121, a Galaxy Group at z=0.35[pdf, other]
  32. submitted to A&A. Comments welcome
  33. Detection of PAH and Far-Infrared Emission from the Cosmic Eye: Pr obing the Dust and Star Formation of Lyman Break Galaxies[pdf, ps, other]
  34. Brian Siana (1), Ian Smail (2), A. Mark Swinbank (2), Johan Richard (2), Harry I. Teplitz (3), Kristen E. K. Coppin (2), Richard S. Ellis (1), Daniel P. Stark (4), Jean-Paul Kneib (5), Alistair C. Edge (2) ((1) Caltech, (2) Durham, (3) Spitzer Science Center, (4) IoA Cambridge, (5) Marseille)
    Accepted for publication in ApJ. 9 pages, 7 figures
  35. Keck spectroscopic survey of strongly lensed galaxies in Abell 1703: further evidence for a relaxed, unimodal cluster[ps, pdf, other]
  36. Johan Richard (ICC/Durham, Caltech), Liuyi Pei (Caltech), Marceau Limousin (Latt, Dark Cosmology Centre), Eric Jullo (LAM/OAMP), Jean-Paul Kneib (LAM/OAMP)
    Comments: 11 pages, 6 figures, accepted for publication in A& A. Replaced with accepted version
  37. A New Window of Exploration in the Mass Spectrum: Strong Lensing by Galaxy Groups in the SL2S[pdf, other]
  38. Comments: Submitted to A&A. Draft with Appendix images can be found at this http URL
  39. Near-IR Search for Lensed Supernovae Behind Galaxy Clusters - II. First Detection and Future Prospects[ps, pdf, other]
  40. The formation and assembly of a typical star-forming galaxy at z~3 [pdf]
  41. Comments: To appear in Nature, Vol 455, Oct 9 2008
  42. Gauging the dark matter fraction in a $L_*$ S0 galaxy at z=0.47 through gravitational lensing from deep HST/ACS imaging[ps, pdf, other]
  43. G. Covone (1,2,3), M. Paolillo (1,3), N.R. Napolitano (2), M. Capaccioli (1,4), G. Longo (1), J.P. Kneib (5), E. Jullo (5,6), J. Richard (7), O. Khovanskaya (8), M. Sazhin (8), N.A. Grogin (9), E. Schreier (10) ((1) University of Nap les "Federico II", (2) INAF, Naples, (3) INFN, Naples, (4) INAF--VSTCeN, Naples (5) OAM P, Marseille, (6) ESO, Santiago, (7) Caltech, Pasadena, (8) Sternberg Astronomical Institute, Mos cow (9) Arizona State University, USA, (10) Associated Universities Inc., USA)
    Comments: 18 pages, 5 figures; accepted for publication in ApJ

  44. A Hubble and Spitzer Space Telescope Survey for Gravitationally-Lensed Galaxies:
    Further Evidence for a Significant Population of Low Luminosity Galaxies beyond Redshift Seven
    [abs, ps, pdf, other]
  45. Authors: Johan Richard (Caltech), Daniel P. Stark (Caltech), Richard S. Ellis (Caltech), Matthew R. George (Caltech), Eiichi Egami (Steward Observatory), Jean-Paul Kneib (LAM/OAMP), Graham P. Smith (U. Birmingham)
    Comments: Accepted for publication in ApJ. ESA/STSCI Press Release available at this http URL

  46. Strong Lensing in Abell 1703: Constraints on the Slope of the Inne r Dark Matter Distribution[pdf, ps, other]
  47. Accepted for publication, conclusion unchanged but strengthened by a serie of tests suggested by a constructive referee report. Higher resolution available at this http URL
  48. Mid-Infrared Spectroscopy of Lensed Galaxies at 1<z<3: The N ature of Sources Near the MIPS Confusion Limit[pdf, ps, other]
  49. Probing the Slope of Cluster Mass Profile with Gravitational Einst ein Rings: Application to Abell 1689[pdf, ps, other]
  50. Accepted for publication in MNRAS. Substantial modification after referee's report
  51. EROs found behind lensing clusters: II.Empirical properties, clas sification, and SED modelling based on multi-wavelength observations[pdf, other]
  52. A. Hempel (1), D. Schaerer (1 and 3), E. Egami (2), R. Pelló (3), M. Wise (4), J. Richard (5 and 3), J.-F. Le Borgne (3), J.-P. Kneib (6) ((1) Observatoire de Gené ve, (2) Steward Observatory, (3) Observatoire Midi-Pyrénées, (4) Astronomical Institute Anton Pannekoek, (5) Caltech Astronomy, (6) OAMP)
    20 pages, 10 figures, accepted for publication in A&amp;A
  53. A Detailed Study of Gas and Star Formation in a Highly Magnified L yman Break Galaxy at z=3.07[pdf, ps, other]
  54. Authors: K.E.K. Coppin (1), A.M. Swinbank (1), R. Neri (2), P. Cox (2), Ian Smail (1), R.S. Ellis (3), J.E. Geach (1), B. Siana (4), H. Teplitz (4), S. Dye (5), J.-P. Kneib (6), A.C. Edge (1), J. Richard (3) ((1) Durham, (2) IRAM, (3) Caltech, (4) Spitzer Science Center, (5) Cardiff, (6) Marseille)
    8 pages, 3 figures, accepted for publication in ApJ
    Journal-ref: Astrophys.J.665:936-943,2007
  55. EROs found behind lensing clusters. II. Stellar populations and dust properties of optical dropout EROs and comparison with related objects [abs, ps, pdf, other]
  56. D. Schaerer (1,2), A. Hempel (1), E. Egami (3), R. Pello (2), J. Richard (2,4), J.F. Le Borgne (2), J.-P. Kneib (5), M. Wise (6), F. Boone (7) ((1) Geneva Observatory, Sauverny, Switzerland, (2) Observatoire Midi-Pyrenees, Toulouse, France, (3) Steward Observatory, Tucson, USA, (4) Caltech Astronomy, Pasadena, USA, (5) OAMP, Marseille, France, (6) Astronomical Institute Anton Pannekoek, Amsterdam, The Netherlands, (7) Observatoire de Paris, Paris, France)
    Comments: 18 pages, 17 figures, accepted for publication in Astronomy and Astrophysics
  57. The strong transformation of spiral galaxies infalling into massive clusters at z~0.2 [abs, ps, pdf, other]
  58. L. Cortese, D. Marcillac, J. Richard, H. Bravo-Alfaro, J.-P. Kneib, G. Rieke, G. Covone, E. Egami, J. Rigby, O. Czoske, J. Davies
    Comments: Accepted for publication on MNRAS (March 2007 issue). 21 pages, 3 tables, 14 figures. Higher resolution version available at this http URL
    ESA/STScI Press Release available at this http URL

  59. A statistical study of multiply-imaged systems in the lensing cluster Abell 68 . [abs, ps, pdf, other]
  60. Full PDF version HERE

    Johan Richard (Caltech), Jean-Paul Kneib (OAMP), Eric Jullo (ESO,OAMP), Giovanni Covone (INAF, Napoli), Marceau Limousin (Dark Cosmology Centre), Richard Ellis (Caltech), Daniel Stark (Caltech), Kevin Bundy (Caltech), Oliver Czoske (Uni. Bonn), Harald Ebeling (IfA), Genevieve Soucail (OMP)

    Comments: 30 pages, 8 figures, accepted for publication in ApJ.
  61. A Keck Survey for Gravitationally-Lensed Lyman-alpha Emitters in the Redshift Range 8.5<z<10.4: New Constraints on the Contribution of Low Luminosity Sources to Cosmic Reionization [abs, ps, pdf, other] :

  62. Daniel P. Stark, Richard S. Ellis, Johan Richard, Jean-Paul Kneib, Graham P. Smith, Michael R. Santos
    Comments: Accepted by ApJ, 27 pages, 12 figures, for higher resolution figures, see this http URL
  63. News from z~6-10 galaxy candidates found behind gravitational lensing clusters [abs, ps, pdf, other] :

  64. D. Schaerer (Obs Genevea, OMP), R. Pello (OMP), E. Egami (Tucson), A. Hempel (Obs Geneva), J. Richard (OMP), J.-F. Le Borgne (OMP), J.-P. Kneib (OAMP, Caltech), M. Wise (Amsterdam), F. Boone (LERMA), F. Combes (LERMA)
    Comments: 6 pages, figs included. To appear in "At the Edge of the Universe: latest results from the deepest astronomical surveys", Eds. Jose Afonso, Henry Ferguson and Ray Norris, ASP Conf. Series, in press
  65. Solving the Abell 1689 puzzle: A combined strong and weak gravitational lensing analysis [abs, ps, pdf, other] :

  66. M. Limousin, J. Richard, J.-P. Kneib, E. Jullo, B. Fort, G. Soucail, A. Elíasdóttir, P. Natarajan, I. Smail, R.S. Ellis, O. Czoske, P. Hudelot, S. Bardeau, H. Ebeling, G.P. Smith
    Comments: 40 pages, 17 figures, high resolution draft at this http URL
  67. A very bright, highly magnified Lyman-break galaxy at z=3.07 [abs, ps, pdf, other] :

  68. Ian Smail (ICC, Durham), A.M. Swinbank (ICC), J. Richard (CIT), H. Ebeling (IfA), J.-P. Kneib (LAM), A.C. Edge (ICC), D. Stark (CIT), R.S. Ellis (CIT), S. Dye (Cardiff), G.P. Smith (Birmingham), C. Mullis (Michigan)
    Comments: In press at ApJL, 4 pages, 2 figures
  69. Searching for the first galaxies through gravitational lenses [abs, ps, pdf, other]

  70. D. Schaerer (1,2), R. Pello (2), J. Richard (2), E. Egami (3), A. Hempel (1), J.F. Le Borgne (2), J.-P. Kneib (4,5), M. Wise (6), F. Boone (7), F. Combes (7) ((1) Geneva Observatory, Sauverny, Switzerland, (2) Observatoire Midi-Pyrenees, Toulouse, France, (3) Steward Observatory, Tucson, USA, (4) OAMP, Marseille, France, (5) Caltech Astronomy, Pasadena, USA, (6) Astronomical Institute Anton Pannekoek, Amsterdam, The Netherlands, (7) Observatoire de Paris, Paris, France)
    Comments: Comments: 4 pages, 4 colour figures, can also be downloaded via this http URL
    Journal-ref: ESO Messenger 125 (2006) 20-23
  71. Constraining the population of 6 < z < 10 star-forming galaxies with deep near-IR images of lensing clusters [abs, ps, pdf, other]

  72. Johan Richard (OMP, Caltech), Roser Pello (OMP), Daniel Schaerer (Obs Geneva, OMP), Jean-Francois Le Borgne (OMP), Jean-Paul Kneib (LAM, Caltech)
    Comments: 35 pages, 19 figures; Accepted for publication in A&A;

    Full PDF version HERE

  73. VIMOS-IFU survey of z~0.2 massive galaxy clusters. I. Observations of the strong lensing cluster Abell 2667 [abs, ps, pdf, other]

  74. Giovanni Covone (1,2), Jean-Paul Kneib (1,3), Geneviève Soucail (4), Johan Richard (3,4), Eric Jullo (1), Harald Ebeling (5)
    (1) Laboratoire d'Astrophysique de Marseille, (2) INAF-OAC, Italy, (3) Caltech, USA (4) Observatoire Midi-Pyrenees, Toulouse, France (5) Institute for Astronomy, Hawaii
    14 pages, 12 figures. Accepted for publication in A&A
  75. Spectrophotometric properties of galaxies at intermediate redshifts (z ~ 0.2--1.0)
    II. The Luminosity -- Metallicity relation
    [abs, ps, pdf, other]

  76. Fabrice Lamareille (1), Thierry Contini (1), Jarle Brinchmann (2,3), Jean-François Le Borgne (1), Stéphane Charlot (2,4), Johan Richard (1)
    (1) Laboratoire d'Astrophysique de Toulouse-Tarbes, (2) MPA, (3) CAUP, (4) Institut d'Astrophysique de Paris
  77. Spectrophotometric properties of galaxies at intermediate redshifts (z ~ 0.2--1.0)
    I. Sample description, photometric properties and spectral measurements
    [abs, ps, pdf, other] :

  78. Fabrice Lamareille (1), Thierry Contini (1), Jean-François Le Borgne (1), Jarle Brinchmann (2, 3), Stéphane Charlot (2,4), Johan Richard (1)

    (1) Laboratoire d'Astrophysique de Toulouse-Tarbes, (2) MPA, (3) CAUP, (4) Institut d'Astrophysique de Paris
    24 pages, accepted by A&A
  79. Looking for z>7 galaxies with the Gravitational Telescope [abs, ps, pdf, other]

  80. Roser Pelló (1), Johan Richard (1), Daniel Schaerer (2,1), Jean-François Le Borgne (1), Jean-Paul Kneib (3), Angela Hempel (2)
    (1) Observatoire Midi-Pyrenees, (2) Geneva Observatory,(3) Laboratoire d'Astrophysique de Marseille
    5 pages, 2 figures. Conference proceedings: "The Fabulous Destiny of Galaxies: Bridging Past and Present", Marseille, June 2005

  81. Spitzer and Hubble Constraints on the Physical Properties of the z~7 Galaxy Strongly Lensed by Abell 2218 [abs, ps, pdf, other]

  82. E. Egami (1), J.-P. Kneib (2,3), G. H. Rieke (1), R. S. Ellis (3), J. Richard (2,3), J. Rigby (1), C. Papovich (1), D. Stark (3), M. R. Santos (4),
    J.-S. Huang (5), H. Dole (1), E. Le Floc'h (1), P. G. Perez-Gonzalez (1)
    (1) Univ. of Arizona, (2) Observatoire Midi-Pyrenees, (3) Caltech, (4) IoA, (5) CfA
    11 pages, 2 figures, 2 tables; Accepted for publication in ApJL
  83. Very High-Redshift Lensed Galaxies [abs, ps, pdf, other]

  84. Roser Pelló (1), Johan Richard (1), D. Schaerer (2 and 1), Jean -François Le Borgne (1), Jean-Paul Kneib (3,1)
    (1) LAOMP/Toulouse (2) Geneva Observatory, (3) Caltech
    14 pages, 7 figures, Proceedings of IAU Symposium No. 225: The Impact of Gravitational Lensing on Cosmology,
    Y. Mellier and G. Meylan, Eds

  85. The EMIR observing program manager system science simulator (DOWNLOAD)

  86. Johan Richard; Roser Pelló; Thierry Contini; Sylvie Brau-Nogué; Christian Lucuix
    Proceedings of the SPIE--The International Society for Optical Engineering-- conference held in Glasgow (June 2004).
    Volume 5493, pp. 373-381 (2004).

  87. Spectrophotometric properties of galaxies: automatic measurement and analysis tools for large surveys (ABSTRACT).

  88. Fabrice Lamareille(1); Thierry Contini(1); Jean-François Le Borgne(1); Jarle Brinchmann(2); Stéphane Charlot(3); Johan Richard(1).
    (1) LAOMP/Toulouse   (2) Inst. Astrophysics Oslo    (3) MPA
    SF2A-2004: Semaine de l'Astrophysique Francaise, meeting held in Paris, France, June 14-18, 2004, Eds.: F. Combes, D. Barret, T. Contini, F. Meynadier and L. Pagani EdP-Sciences, Conference Series.

  89. Observing z>7 sources with the GTC [abs, ps, pdf, other]

  90. Roser Pelló (1), D. Schaerer (2 and 1), Johan Richard (1), Jean -François Le Borgne (1), Jean-Paul Kneib (3,1)
    (1) LAOMP/Toulouse (2) Geneva Observatory, (3) Caltech
    5 Latex pages, 4 figures, Proceedings of the II International Workshop on
    Science with the GTC, February 15-17, 2004. To be published in Rev.Mex.A.A. CS

  91. ISAAC/VLT observations of a lensed galaxy at z=10.0 [abs, ps, pdf, other ]

  92. Roser Pelló (1), Daniel Schaerer (2,1), Johan Richard (1), Jean-François Le Borgne (1), Jean-Paul Kneib (3, 1)
    (1) LAOMP/Toulouse, (2) Geneva Observatory, (3) Caltech
    To be published in A&A, Vol. 416, p. L35.
    Press release information, additional figures and information available at this http URL and this http URL

  93. A Probable z~7 Galaxy Strongly Lensed by the Rich Cluster Abell 2218: Exploring the Dark Ages [abs , ps , pdf , other >

  94. Jean-Paul Kneib (1,2), Richard S. Ellis (2), Michael R. Santos (2,3), Johan Richard (1)
    (1) LAOMP/Toulouse, (2) Caltech, (3) IoA Cambridge
    20 pages, accepted by the Astrophysical Journal

  95. The Abundance of Low-luminosity Lyman alpha Emitters at High Redshift [abs , ps , pdf , other ]

  96. Michael R. Santos (1), Richard S. Ellis (1), Jean-Paul Kneib (1,2), Johan Richard (2), Konrad Kuijken (3)
    (1) Caltech, (2) LAOMP/Toulouse, (3) Leiden 
    22 pages, 14 figures, accepted for publication in the Astrophysical Journal

  97. Discovery of a faint R-band drop-out: a strongly reddened lensed star forming galaxy at z=1.68 [abs , ps , pdf , other]

  98. Johan Richard (1), Daniel Schaerer (2,1), Roser Pelló (1), Jean-François Leborgne (1), Jean-Paul Kneib (1,3)
    (1) LAOMP/Toulouse, (2) Geneva Observatory, (3) Caltech
    5 pages, 5 figures, accepted for publication in A&A letters

  99. Searches for high redshift galaxies using gravitational lensing [abs , ps , pdf , other ]

  100. Johan Richard (1), Roser Pelló (1), Jean-Paul Kneib (1,2), D. Schaerer (3,1), Michael R. Santos (2), Richard Ellis (2)
    (1) LAOMP/Toulouse, (2) Caltech, (3) Geneva Observatory
    Proceedings of the "Multiwavelength Cosmology" conference lead in Mykonos (17th-20th june 2003). 4 pages, 5 figures
  101. Properties of Faint Distant Galaxies as seen through Gravitational Telescopes [abs , ps , pdf , other ]

  102. Roser Pelló, Thierry Contini, Marie Lemoine-Busserolle, Johan Richard, Jean-Paul Kneib, Jean-François Le Borgne,
    Daniel Schaerer, Micol Bolzonella
    Review lecture given at "Gravitational Lensing: a unique tool for cosmology",Aussois, France, January 2003.
    To appear in ASP Conf. S., eds. D. Valls-Gabaud & J.-P. Kneib, 26 pages, 8 figures.