From Z > 6 to Z ∼ 2: Unearthing Galaxies at the Edge of the Dark Ages

  • Garth Illingworth
  • Rychard Bouwens
Conference paper
Part of the Astrophysics and Space Science Library book series (ASSL, volume 319)


Galaxies undergoing formation and evolution can now be directly observed over a time baseline of some 12 Gyr. An inherent difficulty with high—redshift observations is that the objects are very faint and the best resolution (HST) is only ~ 0.5 kpc. Such studies thereby combine in a highly synergistic way with the great detail that can be obtained for nearby galaxies through “archaeological” studies. Remarkable advances are being made in many areas, due to the power of our observatories on the ground and in space, particularly the unique capabilities of the HST ACS. Three new developments are highlighted. First, is the derivation of stellar masses for galaxies from spectral energy distributions (SEDs) using HST and now Spitzer data, and dynamical masses from both sub—mm observations of CO lines and near—IR observations of optical nebular lines like Ha. A major step has been taken with evidence that points to the z ~ 2 – 3 LBGs having masses that are a few ×1010 M . Second is the discovery of a new population of red, evolved galaxies, again at redshifts z ~ 2 – 3 which appear to be the progenitors of the more massive early—type galaxies of today, with dynamical masses around a few ×1011 M . Third are the remarkable advances that have occurred in characterizing drop—out galaxies (LBGs) to z ~ 6 and beyond, less than 1 Gyr from recombination. The HST ACS has played a key role here, with the dropout technique being applied to i and z images in several deep ACS fields, yielding large samples of these objects. This has allowed a detailed determination of their properties (e.g., size, color), and meaningful comparisons against lower—redshift dropout samples. The use of cloning techniques has overcome many of the strong selection biases that affect the study of high redshift populations. A clear trend of size with redshift has been identified, and its impact on the luminosity density and star formation rate estimated. There is a significant, though modest, decrease in the star formation rate from redshifts z ~ 2.5 out through z ~ 6. The latest data also allow for the first robust determination of the luminosity function at z ~ 6. Last, but not least, the latest UDF ACS (optical) and NICMOS (near—IR) data has resulted in the detection of some galaxies at z ~ 7 – 8.


Galaxy Formation Galaxy Evolution High Redshift Galaxies 


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  1. Barmby, P., et al. ApJS., in press, astro-ph/0405624 (2004).Google Scholar
  2. Bennett, C. L., et al. ApJS., 148, 97 (2003).ADSCrossRefGoogle Scholar
  3. Bouwens, R., Broadhurst, T. & Silk, J. ApJ., 506, 557 (1998).ADSCrossRefGoogle Scholar
  4. Bouwens, R., Broadhurst, T., & Illingworth, G. ApJ., 593, 640 (2003a).ADSCrossRefGoogle Scholar
  5. Bouwens, R. J., et al. ApJ., 595, 589 (2003b).ADSCrossRefGoogle Scholar
  6. Bouwens, R. J., et al. ApJL., 606, L25 (2004a).ADSCrossRefGoogle Scholar
  7. Bouwens, R. J. et al. ApJL., in press (2004b).Google Scholar
  8. Bouwens, R. J. et al. ApJ., submitted (2004c).Google Scholar
  9. Bouwens, R. J. et al. ApJ., in preparation (2004d).Google Scholar
  10. Bouwens, R. J. et al. ApJ., in preparation (2004e).Google Scholar
  11. Bruzual, G. & Charlot, S. MNRAS, 344, 1000 (2003).ADSCrossRefGoogle Scholar
  12. Bunker, A. J., et al. MNRAS, 342, L47 (2003).ADSCrossRefGoogle Scholar
  13. Dickinson, M., et al. ApJL., 600, L99 (2004).ADSCrossRefGoogle Scholar
  14. Dickinson, M., Papovich, C., Ferguson, H. C., and Budavari, T. ApJ., 587, 25 (2003).ADSCrossRefGoogle Scholar
  15. Erb, D. K., et al. ApJ., 591, 101 (2003).ADSCrossRefGoogle Scholar
  16. Erb, D.K., et al. ApJ., in press, astro-ph/0404235 (2004).Google Scholar
  17. Ferguson, H.C., et al. ApJL., 600, L107 (2004).ADSCrossRefGoogle Scholar
  18. Ford, H. C. et al. Proc. SPIE, 4854, 81 (2003).Google Scholar
  19. Forster Schreiber, N.M., ApJ., in press (2004).Google Scholar
  20. Franx, M., et al. ApJL., 486, L75 (1997).ADSCrossRefGoogle Scholar
  21. Franx, M., et al. ApJL., 587, L79 (2003).ADSCrossRefGoogle Scholar
  22. Fukugita, M., Hogan, C. J., and Peebles, P. J. E. ApJ., 503, 518 (1998).ADSCrossRefGoogle Scholar
  23. Giavalisco, M., et al. ApJL., 600, L93 (2004).ADSCrossRefGoogle Scholar
  24. Genzel, R., et al. ApJ., 584, 633 (2003).ADSCrossRefGoogle Scholar
  25. Kogut, A., et al. ApJS., 148, 161 (2003).ADSCrossRefGoogle Scholar
  26. Lidman, C., et al. A.and A., in press (2004).Google Scholar
  27. Lilly, S.J., Le Fevre, O., Hammer, F., and Crampton, D. ApJ., 460, Ll (1996).ADSCrossRefGoogle Scholar
  28. Madau, P., Pozzetti, L. and Dickinson, M. ApJ., 498, 106 (1998).ADSCrossRefGoogle Scholar
  29. Mo, H. J., Mao, S., and White, S. D. M. MNRAS, 295, 319 (1998).ADSCrossRefGoogle Scholar
  30. Papovich, C., Dickinson, M., and Ferguson, H. C. ApJ., 559, 620 (2001).ADSCrossRefGoogle Scholar
  31. Rosati, P., et al. ApJ., 492, L21 (1998).ADSCrossRefGoogle Scholar
  32. Rudnick, G., et al. ApJ., 599, 847 (2003).ADSCrossRefGoogle Scholar
  33. Shapley, A.S., et al. ApJ., in press, astro-ph/0405187 (2004).Google Scholar
  34. Stanway, E. R., Bunker, A. J., and McMahon, R. G. MNRAS, 342, 439 (2003).ADSCrossRefGoogle Scholar
  35. Stanway, E. R., et al. ApJL., 604, L13 (2004).ADSCrossRefGoogle Scholar
  36. Steidel, C.C., et al. ApJ., 519, 1 (1999).ADSCrossRefGoogle Scholar
  37. Thompson, R. I., Weymann, R. J., and Storrie-Lombardi, L. J. ApJ., 546, 694 (2001).ADSCrossRefGoogle Scholar
  38. Thompson, R. I., et al., in preparation, (2004).Google Scholar
  39. van Dokkum, P.G., et al. ApJL., 587, L83 (2003).ADSCrossRefGoogle Scholar
  40. van Dokkum, P.G., et al. ApJ., in press, astro-ph/0405482 (2004).Google Scholar
  41. Weymann, R. J., et al. ApJL., 505, L95 (1998).ADSCrossRefGoogle Scholar
  42. Yan, H., Windhorst, R. A., and Cohen, S. H. ApJL., 585, L93 (2003).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2004

Authors and Affiliations

  • Garth Illingworth
    • 1
  • Rychard Bouwens
    • 1
  1. 1.UCO/Lick ObservatoryUniversity of CaliforniaSanta CruzUSA

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