The nature of star formation in lensed galaxies at high redshift
Abstract
We present near-infrared photometry of all available gravitationally lensed 'arcs' with spectroscopic redshifts. By combining this photometry with optical data, we find that the bulk of the systems with z ~ 1 are intrinsically blue across the rest-frame spectral region 2000 Å to 1 μm. Using a combination of optical and optical-infrared colours, we demonstrate that these systems cannot be blue by virtue of a secondary burst of star formation superimposed on an evolved population, but we are unable to distinguish directly between major star formation events in a generic young galaxy and an extended era of constant star formation typical of late-type spirals. Using various arguments, we conclude that our arcs represent modest gravitational magnification of typical field galaxies. Consequently, if the star formation seen is representative of that in field galaxies at z ≥ 1, the absence of high-redshift galaxies in current deep spectroscopic surveys to b_J ≃ 24 supports the hypothesis that the bulk of the star formation in normal galaxies occurred over an extended era up to the epoch corresponding to z ~ 1.
Additional Information
© 1993 Royal Astronomical Society. Provided by the NASA Astrophysics Data System. Accepted 1993 January 27. Received 1992 December 3; in original form 1992 May 5. We thank PATT for generous support of the UKIRT arc programme over a number of semesters, and all the UKIRT staff, particularly Malcolm Smith and Tom Geballe, for their invaluable help in technical matters and in obtaining service exposures. We acknowledge cheerful assistance from the telescope operators Dolores Walther, Joel Aycock and Thor Wold. Mark Casali is thanked for writing data reduction software specifically to enable us to monitor our progress at the telescope. Useful discussions have been held with Simon Lilly, Len Cowie, Roger Blandford and David Koo. RSE and IS acknowledge financial support from the SERC. AAS acknowledges financial support from the Spanish Ministerio de Educación y Ciencia.Attached Files
Published - mnras263-0628.pdf
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Additional details
- Eprint ID
- 108054
- Resolver ID
- CaltechAUTHORS:20210212-191304356
- Science and Engineering Research Council (SERC)
- Ministerio de Educación y Ciencia (MEC)
- Created
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2021-02-16Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field