CaltechAUTHORS
Published March 2008 | Version Published
Journal Article Open

The Hα luminosity function and star formation rate at z ≈ 0.24 in the COSMOS 2 square degree field

Creators

  • 1. ROR icon Ehime University
  • 2. ROR icon Tohoku University
  • 3. ROR icon California Institute of Technology
  • 4. ROR icon National Astronomical Observatory of Japan
  • 5. ROR icon University of Hawaii at Manoa
  • 6. ROR icon Space Telescope Science Institute
  • 7. ROR icon CEA Saclay
  • 8. ROR icon Brera Astronomical Observatory
  • 9. ROR icon Max Planck Institute for Extraterrestrial Physics
  • 10. ROR icon University of Arizona
  • 11. ROR icon Laboratoire d'Astrophysique de Marseille
  • 12. ROR icon ETH Zurich
  • 13. ROR icon European Southern Observatory
  • 14. ROR icon University of California, Los Angeles
  • 15. ROR icon Max Planck Institute for Astronomy
  • 16. ROR icon Jet Propulsion Lab

Abstract

To derive a new Hα luminosity function and to understand the clustering properties of star-forming galaxies at z≈ 0.24, we have made a narrowband imaging survey for Hα-emitting galaxies in the Hubble Space Telescope (HST) COSMOS 2 square degree field. We used the narrowband filter NB816 (λ_c = 8150 Å, Δ λ = 120 Å) and sampled Hα emitters with EW_(obs)(H α + [N II]) > 12Å in a redshift range between z = 0.233 and 0.251 corresponding to a depth of 70 Mpc. We obtained 980 Hα-emitting galaxies in a sky area of 5540 arcmin^2, corresponding to a survey volume of 3.1 × 10^4 Mpc^3. We derive a Hα luminosity function with a best-fit Schechter function parameter set of α = − 1.35_(−0.13)^(+0.11), log ф_* = − 2.65_(−0.38)^(+0.27), and log L_*(ergs s^(−1)) = 41.94_(−0.23)^(+0.38). The Hα luminosity density is 2.7_(−0.6)^(+0.7) × 10^(39) ergs s^(−1) Mpc^(−3). After subtracting the AGN contribution (15%) to the Hα luminosity density, the star formation rate density is evaluated as 1.8_(−0.4)^(+0.7) × 10^(−2) M_סּ yr^(−1) Mpc^(−3). The angular two-point correlation function of Hα-emitting galaxies of log L(H α) > 39.8 is well fit by a power-law form of w(θ) = 0.013−_(0.001)^(+0.002)θ^(−0.88 ± 0.03), corresponding to the correlation function of ξ (r) = (r/1.9 Mpc)^(−1.88). We also find that the Hα emitters with higher Hα luminosity are more strongly clustered than those with lower luminosity.

Additional Information

© 2008. The American Astronomical Society. Received 2006 September 10; accepted 2007 September 5. The HST COSMOS Treasury program was supported through NASA grant HST-GO-09822.We greatly acknowledge the contributions of the entire COSMOS collaboration consisting of more than 70 scientists. The COSMOS science meeting in 2005 May was supported by in part by the NSF through grant OISE-0456439.We would also like to thank the Subaru Telescope staff for their invaluable help. This work was financially supported in part by the JSPS (nos. 15340059 and 17253001). S. S. S. and T. N. are JSPS fellows.

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Additional details

Identifiers

Eprint ID
14372
Resolver ID
CaltechAUTHORS:20090608-114235177

Funding

NASA
HST-GO-09822
NSF
OISE-0456439
Japan Society for the Promotion of Science (JSPS)
15340059
Japan Society for the Promotion of Science (JSPS)
17253001

Dates

Created
2009-08-28
Created from EPrint's datestamp field
Updated
2021-11-08
Created from EPrint's last_modified field

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Caltech groups
Infrared Processing and Analysis Center (IPAC)