Skip to main content

Research Repository

Advanced Search

The 2dF Galaxy Redshift Survey: Constraints on Cosmic Star Formation History from the Cosmic Spectrum.

Baldry, Ivan K.; Glazebrook, Karl; Baugh, Carlton M.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Cole, Shaun; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; De Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Frenk, Carlos S.; Hawkins, Edward; Jackson, Carole; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve; Madgwick, Darren S.; Norberg, Peder; Peacock, John A.; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith


Ivan K. Baldry

Karl Glazebrook

Joss Bland-Hawthorn

Terry Bridges

Russell Cannon

Matthew Colless

Chris Collins

Warrick Couch

Gavin Dalton

Roberto De Propris

Simon P. Driver

George Efstathiou

Richard S. Ellis

Edward Hawkins

Carole Jackson

Ofer Lahav

Ian Lewis

Stuart Lumsden

Steve Maddox

Darren S. Madgwick

John A. Peacock

Bruce A. Peterson

Will Sutherland

Keith Taylor


We present the first results on the history of star formation in the universe based on the "cosmic spectrum," in particular the volume-averaged, luminosity-weighted, stellar absorption-line spectrum of present-day galaxies from the 2dF Galaxy Redshift Survey. This method is novel in that, unlike previous studies, it is not an estimator based on total luminosity density. The cosmic spectrum is fitted with models of population synthesis, tracing the history of star formation before the epoch of the observed galaxies, using a method we have developed that decouples continuum and spectral line variations and is robust against spectrophotometric uncertainties. The cosmic spectrum can only be fitted with models incorporating chemical evolution, and it indicates that there was a peak in the star formation rate (SFR) in the past of at least 3 times the current value and that the increase back to z = 1, assuming it scales as (1 + z)β, has a strong upper limit of β < 5. We find, in the general case, that there is some model degeneracy between star formation at low and high redshift. However, if we incorporate previous work on star formation at z < 1, we can put strong upper limits on the star formation rate at z > 1: e.g., if β > 2, then the SFR for 1 < z < 5 scales as (1 + z)α, with α < 2. This is equivalent to stating that no more than 80% of stars in the universe formed at z > 1. Our results are consistent with the best-fit results from compilations of cosmic SFR estimates based on UV luminosity density, which yield 1.8 < β < 2.9 and -1.0 < α < 0.7, and are also consistent with estimates of Ωstars based on the K-band luminosity density.


Baldry, I. K., Glazebrook, K., Baugh, C. M., Bland-Hawthorn, J., Bridges, T., Cannon, R., …Taylor, K. (2002). The 2dF Galaxy Redshift Survey: Constraints on Cosmic Star Formation History from the Cosmic Spectrum. Astrophysical Journal, 569(2), 582-594.

Journal Article Type Article
Acceptance Date Jan 3, 2002
Publication Date 2002-04
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 569
Issue 2
Pages 582-594