The mass evolution of the first galaxies: Stellar mass functions and star formation rates at 4 < z < 7 in the CANDELS GOODS-south field

K. Duncan, C. J. Conselice, A. Mortlock, W. G. Hartley, Y. Guo, H. C. Ferguson, Romeel S Dave, Y. Lu, J. Ownsworth, M. L N Ashby, A. Dekel, M. Dickinson, S. Faber, M. Giavalisco, N. Grogin, D. Kocevski, A. Koekemoer, R. S. Somerville, C. E. White

Research output: Contribution to journalArticle

123 Citations (Scopus)

Abstract

We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ~ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed M<inf>UV</inf>-M<inf>*</inf> relation has a shallow slope more consistent with a constant mass-to-light ratio and a normalization which evolves with redshift. Our stellar mass functions have steep low-mass slopes (α ≈ -1.9), steeper than previously observed at these redshifts and closer to that of theUVluminosity function. Integrating our new mass functions, we find the observed stellar mass density evolves from log<inf>10</inf> ρ<inf>*</inf> = 6.64<sup>+0.58</sup> <inf>-0.89</inf> at z ~ 7 to 7.36 ± 0.06 M<inf>⊙</inf> Mpc<sup>-3</sup> at z ~ 4. Finally, combining the measured UV continuum slopes (β) with their rest-frame UV luminosities, we calculate dust-corrected star formation rates (SFR) for our sample. We find the specific SFR for a fixed stellar mass increases with redshift whilst the global SFR density falls rapidly over this period. Our new SFR density estimates are higher than previously observed at this redshift.

Original languageEnglish (US)
Pages (from-to)2960-2984
Number of pages25
JournalMonthly Notices of the Royal Astronomical Society
Volume444
Issue number3
DOIs
StatePublished - 2014
Externally publishedYes

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star formation rate
stellar mass
galaxies
slopes
estimates
luminosity
continuums
mass to light ratios
spectral energy distribution
rate
goods
dust
near infrared

Keywords

  • Galaxies: Evolution
  • Galaxies: Formation
  • Galaxies: High-redshift
  • Galaxies: Luminosity function, mass function

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

The mass evolution of the first galaxies : Stellar mass functions and star formation rates at 4 < z < 7 in the CANDELS GOODS-south field. / Duncan, K.; Conselice, C. J.; Mortlock, A.; Hartley, W. G.; Guo, Y.; Ferguson, H. C.; Dave, Romeel S; Lu, Y.; Ownsworth, J.; Ashby, M. L N; Dekel, A.; Dickinson, M.; Faber, S.; Giavalisco, M.; Grogin, N.; Kocevski, D.; Koekemoer, A.; Somerville, R. S.; White, C. E.

In: Monthly Notices of the Royal Astronomical Society, Vol. 444, No. 3, 2014, p. 2960-2984.

Research output: Contribution to journalArticle

Duncan, K, Conselice, CJ, Mortlock, A, Hartley, WG, Guo, Y, Ferguson, HC, Dave, RS, Lu, Y, Ownsworth, J, Ashby, MLN, Dekel, A, Dickinson, M, Faber, S, Giavalisco, M, Grogin, N, Kocevski, D, Koekemoer, A, Somerville, RS & White, CE 2014, 'The mass evolution of the first galaxies: Stellar mass functions and star formation rates at 4 < z < 7 in the CANDELS GOODS-south field', Monthly Notices of the Royal Astronomical Society, vol. 444, no. 3, pp. 2960-2984. https://doi.org/10.1093/mnras/stu1622
Duncan, K. ; Conselice, C. J. ; Mortlock, A. ; Hartley, W. G. ; Guo, Y. ; Ferguson, H. C. ; Dave, Romeel S ; Lu, Y. ; Ownsworth, J. ; Ashby, M. L N ; Dekel, A. ; Dickinson, M. ; Faber, S. ; Giavalisco, M. ; Grogin, N. ; Kocevski, D. ; Koekemoer, A. ; Somerville, R. S. ; White, C. E. / The mass evolution of the first galaxies : Stellar mass functions and star formation rates at 4 < z < 7 in the CANDELS GOODS-south field. In: Monthly Notices of the Royal Astronomical Society. 2014 ; Vol. 444, No. 3. pp. 2960-2984.
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title = "The mass evolution of the first galaxies: Stellar mass functions and star formation rates at 4 < z < 7 in the CANDELS GOODS-south field",
abstract = "We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ~ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed MUV-M* relation has a shallow slope more consistent with a constant mass-to-light ratio and a normalization which evolves with redshift. Our stellar mass functions have steep low-mass slopes (α ≈ -1.9), steeper than previously observed at these redshifts and closer to that of theUVluminosity function. Integrating our new mass functions, we find the observed stellar mass density evolves from log10 ρ* = 6.64+0.58 -0.89 at z ~ 7 to 7.36 ± 0.06 M⊙ Mpc-3 at z ~ 4. Finally, combining the measured UV continuum slopes (β) with their rest-frame UV luminosities, we calculate dust-corrected star formation rates (SFR) for our sample. We find the specific SFR for a fixed stellar mass increases with redshift whilst the global SFR density falls rapidly over this period. Our new SFR density estimates are higher than previously observed at this redshift.",
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T2 - Stellar mass functions and star formation rates at 4 < z < 7 in the CANDELS GOODS-south field

AU - Duncan, K.

AU - Conselice, C. J.

AU - Mortlock, A.

AU - Hartley, W. G.

AU - Guo, Y.

AU - Ferguson, H. C.

AU - Dave, Romeel S

AU - Lu, Y.

AU - Ownsworth, J.

AU - Ashby, M. L N

AU - Dekel, A.

AU - Dickinson, M.

AU - Faber, S.

AU - Giavalisco, M.

AU - Grogin, N.

AU - Kocevski, D.

AU - Koekemoer, A.

AU - Somerville, R. S.

AU - White, C. E.

PY - 2014

Y1 - 2014

N2 - We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ~ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed MUV-M* relation has a shallow slope more consistent with a constant mass-to-light ratio and a normalization which evolves with redshift. Our stellar mass functions have steep low-mass slopes (α ≈ -1.9), steeper than previously observed at these redshifts and closer to that of theUVluminosity function. Integrating our new mass functions, we find the observed stellar mass density evolves from log10 ρ* = 6.64+0.58 -0.89 at z ~ 7 to 7.36 ± 0.06 M⊙ Mpc-3 at z ~ 4. Finally, combining the measured UV continuum slopes (β) with their rest-frame UV luminosities, we calculate dust-corrected star formation rates (SFR) for our sample. We find the specific SFR for a fixed stellar mass increases with redshift whilst the global SFR density falls rapidly over this period. Our new SFR density estimates are higher than previously observed at this redshift.

AB - We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ~ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed MUV-M* relation has a shallow slope more consistent with a constant mass-to-light ratio and a normalization which evolves with redshift. Our stellar mass functions have steep low-mass slopes (α ≈ -1.9), steeper than previously observed at these redshifts and closer to that of theUVluminosity function. Integrating our new mass functions, we find the observed stellar mass density evolves from log10 ρ* = 6.64+0.58 -0.89 at z ~ 7 to 7.36 ± 0.06 M⊙ Mpc-3 at z ~ 4. Finally, combining the measured UV continuum slopes (β) with their rest-frame UV luminosities, we calculate dust-corrected star formation rates (SFR) for our sample. We find the specific SFR for a fixed stellar mass increases with redshift whilst the global SFR density falls rapidly over this period. Our new SFR density estimates are higher than previously observed at this redshift.

KW - Galaxies: Evolution

KW - Galaxies: Formation

KW - Galaxies: High-redshift

KW - Galaxies: Luminosity function, mass function

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