Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published June 2001 | Published + Accepted Version
Journal Article Open

Caltech Faint Galaxy Redshift Survey. XIII. Spectral Energy Distributions for Galaxies in the Region of the Hubble Deep Field North


We introduce a new empirical function for modeling the spectral energy distributions (SEDs) of galaxies. We apply it to a sample of 590 galaxies in the region of the Hubble Deep Field (HDF) with z< 1.5 using multicolor photometry with wide wavelength coverage combined with spectroscopic redshifts from our 93% complete R-selected redshift survey there. We find the following: 1. As expected, galaxies with strong signs of recent star formation (i.e., those that show emission lines) have bluer continua in both the rest-frame ultraviolet and optical/near-infrared. 2. The redder galaxies tend to be more luminous. Although galaxies with strong absorption lines and no emission features are ~15% of the total sample with 0.25 < z < 0.8, they are ~50% of the 25 most luminous galaxies in the sample at rest-frame R. 3. The SEDs of actively star-forming galaxies become bluer in the mean in the rest-frame UV at higher redshifts, a trend that might arise from SED modeling errors. Aside from this, we discern no change with redshift in the relationship between SED characteristics and galaxy spectral type based on the strength of narrow emission and absorption features. 4. Combining with similar work at higher and lower redshift, the bluest galaxies have indistinguishable SEDs in the rest-frame UV over the redshift regime of 0–3. There is no evidence in our R-selected sample that supports the existence of a substantial population of very dusty star-forming galaxies at z ≾ 1.5. 5. Our ability to predict the mid-IR flux using the UV, optical, and near-IR SEDs is limited. 6. The potential accuracy of photometric redshifts is evaluated, bearing in mind that a break at 4000 Å must be detectable to within the errors of the photometry to assign a photo-z for galaxies in this redshift regime. 7. The rest-frame K-band luminosity as a function of redshift clearly shows a gradual change in the population of various types of galaxies, with star-forming galaxies becoming both more luminous and a larger fraction of the total population at higher redshifts. 8. The overall pattern of the L(K)-z relationship suggests that passive evolution at constant stellar mass is a good approximation to the actual behavior of at least the most luminous galaxies in this large sample of galaxies in the region of the HDF out to z ~ 1.5.

Additional Information

© 2001 The American Astronomical Society. Received 2000 May 15; accepted 2001 March 12. Based in large part on observations obtained at the W.M. Keck Observatory, which is operated jointly by the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The entire Keck/LRIS user community owes a huge debt to Jerry Nelson, Gerry Smith, Bev Oke, and many other people who have worked to make the Keck Telescope and LRIS a reality. We are grateful to the W.M. Keck Foundation, and particularly its late president, Howard Keck, for the vision to fund the construction of the W.M. Keck Observatory. We thank Roger Blandford, David Hogg, and Gerry Neugebauer for helpful discussions, as well as Amy Barger and Len Cowie for access to their unpublished photometric database for the region of the HDF-N. We also thank Robert Brunner for supplying filter transmission curves and two anonymous referees for constructive criticism of the manuscript. This work was not supported by any federal agency.

Attached Files

Published - Cohen_2001_AJ_121_2895.pdf

Accepted Version - 0101251.pdf


Files (984.7 kB)
Name Size Download all
419.9 kB Preview Download
564.8 kB Preview Download

Additional details

August 19, 2023
October 20, 2023