Evidence for Galaxy Formation at High Redshift.

Shanks, T.; Metcalfe, N.; Fong, D.; McCracken, H.; Campos, A.; Thompson, D.

Abstract

We present new evidence that simple evolutionary models where the star-formation rate in galaxies increases exponentially with redshift but the space density of galaxies remains constant with redshift, give very precise fits to the number count of Lyman break, UV dropout, galaxies detected at z≈3. This suggests a possible identification of the brightest Lyman break galaxies at z≈3 with the evolved population of bright spiral galaxies at the present day. The models also fit well the bright B dropout galaxies at z≈4, although the models start to overestimate the observed numbers of dwarf galaxies at this redshift. This suggests that although we may be detecting the epoch of formation of dwarf galaxies at z≈4, the epoch formation of bright galaxies lies at still higher redshift. Finally, there are significant numbers of galaxies now being detected by R dropout in the range 5.3<z<6.7. In the Herschel and Hubble Deep Fields again the number of candidate z≈6 galaxies we find is close to the predictions of the above simple, constant space-density models. The handful of spectroscopically confirmed z≈6 galaxies is also not inconsistent with these model predictions. The suggested picture is one where dwarf galaxies may have formed at z≈4 but brighter galaxies may have formed at significantly earlier redshifts.

Citation

Shanks, T., Metcalfe, N., Fong, D., McCracken, H., Campos, A., & Thompson, D. (2000, August). Evidence for Galaxy Formation at High Redshift. Presented at The Extragalactic Infrared Background and its Cosmological Implications., Manchester, UK

• Presentation Conference Type: Conference Paper (published)
• Conference Name: The Extragalactic Infrared Background and its Cosmological Implications.
• Start Date: Aug 18, 2000
• End Date: Aug 18, 2000
• Publication Date: 2001
• Volume: 204
• Series Title: IAU Symposium.
• Public URL: https://durham-repository.worktribe.com/output/1165542
• Publisher URL: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001IAUS..204..347S&db_key=AST