Spitzer constraints on the stellar populations of Lyα-emitting galaxies at z = 3.1

Kamson Lai, Jia Sheng Huang, Giovanni Fazio, Eric Gawiser, Robin Ciardullo, Maaike Damen, Mardn Franx, Caryl Gronwall, Ivo Labbe, Georgios Magdis, Pieter Van Dokkum

Research output: Contribution to journalArticle

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Abstract

We investigate the stellar populations of a sample of 162 Lyα-emitting galaxies (LAEs) at z = 3.1 in the Extended Chandra Deep Field South, using deep Spitzer IRAC data available from the GOODS and SIMPLE surveys to derive reliable stellar population estimates. We divide the LAEs according to their rest-frame near-IR luminosities into IRAC-detected and IRAC-undetected samples. About 70% of the LAEs are undetected in 3.6 μm down to m 3.6 = 25.2 AB. Stacking analysis reveals that the average stellar population of the IRAC-undetected sample has an age of ∼200 Myr and a mass of ∼3 × 108 M, consistent with the expectation that LAEs are mostly young and low-mass galaxies. On the other hand, the IRAC-detected LAEs are on average significantly older and more massive, with an average age ≳1 Gyr and mass ∼1010M. Comparing the IRAC colors and magnitudes of the LAEs to z ∼ 3 Lyman break galaxies (LBGs) shows that the IRAC-detected LAEs lie at the faint blue end of the LBG color-magnitude distribution, suggesting that IRAC-detected LAEs may be the low-mass extension of the LBG population. We also present tentative evidence for a small fraction (∼5%) of obscured AGNs within the LAE sample. Our results suggest that LAEs posses a wide range of ages and masses. In addition, the presence of evolved stellar populations inside LAEs suggests that the Lyα-luminous phase of galaxies may be either a long-lasting or recurring phenomenon.

Original languageEnglish (US)
Pages (from-to)70-74
Number of pages5
JournalAstrophysical Journal
Volume674
Issue number1
DOIs
StatePublished - Feb 10 2008

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galaxies
stacking
color
luminosity

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Cosmology: observations
  • Galaxies: evolution
  • Galaxies: high-redshift
  • Galaxies: stellar content

Cite this

Lai, K., Huang, J. S., Fazio, G., Gawiser, E., Ciardullo, R., Damen, M., ... Van Dokkum, P. (2008). Spitzer constraints on the stellar populations of Lyα-emitting galaxies at z = 3.1. Astrophysical Journal, 674(1), 70-74. https://doi.org/10.1086/524702
Lai, Kamson ; Huang, Jia Sheng ; Fazio, Giovanni ; Gawiser, Eric ; Ciardullo, Robin ; Damen, Maaike ; Franx, Mardn ; Gronwall, Caryl ; Labbe, Ivo ; Magdis, Georgios ; Van Dokkum, Pieter. / Spitzer constraints on the stellar populations of Lyα-emitting galaxies at z = 3.1. In: Astrophysical Journal. 2008 ; Vol. 674, No. 1. pp. 70-74.
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abstract = "We investigate the stellar populations of a sample of 162 Lyα-emitting galaxies (LAEs) at z = 3.1 in the Extended Chandra Deep Field South, using deep Spitzer IRAC data available from the GOODS and SIMPLE surveys to derive reliable stellar population estimates. We divide the LAEs according to their rest-frame near-IR luminosities into IRAC-detected and IRAC-undetected samples. About 70{\%} of the LAEs are undetected in 3.6 μm down to m 3.6 = 25.2 AB. Stacking analysis reveals that the average stellar population of the IRAC-undetected sample has an age of ∼200 Myr and a mass of ∼3 × 108 M⊙, consistent with the expectation that LAEs are mostly young and low-mass galaxies. On the other hand, the IRAC-detected LAEs are on average significantly older and more massive, with an average age ≳1 Gyr and mass ∼1010M⊙. Comparing the IRAC colors and magnitudes of the LAEs to z ∼ 3 Lyman break galaxies (LBGs) shows that the IRAC-detected LAEs lie at the faint blue end of the LBG color-magnitude distribution, suggesting that IRAC-detected LAEs may be the low-mass extension of the LBG population. We also present tentative evidence for a small fraction (∼5{\%}) of obscured AGNs within the LAE sample. Our results suggest that LAEs posses a wide range of ages and masses. In addition, the presence of evolved stellar populations inside LAEs suggests that the Lyα-luminous phase of galaxies may be either a long-lasting or recurring phenomenon.",
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Lai, K, Huang, JS, Fazio, G, Gawiser, E, Ciardullo, R, Damen, M, Franx, M, Gronwall, C, Labbe, I, Magdis, G & Van Dokkum, P 2008, 'Spitzer constraints on the stellar populations of Lyα-emitting galaxies at z = 3.1', Astrophysical Journal, vol. 674, no. 1, pp. 70-74. https://doi.org/10.1086/524702

Spitzer constraints on the stellar populations of Lyα-emitting galaxies at z = 3.1. / Lai, Kamson; Huang, Jia Sheng; Fazio, Giovanni; Gawiser, Eric; Ciardullo, Robin; Damen, Maaike; Franx, Mardn; Gronwall, Caryl; Labbe, Ivo; Magdis, Georgios; Van Dokkum, Pieter.

In: Astrophysical Journal, Vol. 674, No. 1, 10.02.2008, p. 70-74.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Spitzer constraints on the stellar populations of Lyα-emitting galaxies at z = 3.1

AU - Lai, Kamson

AU - Huang, Jia Sheng

AU - Fazio, Giovanni

AU - Gawiser, Eric

AU - Ciardullo, Robin

AU - Damen, Maaike

AU - Franx, Mardn

AU - Gronwall, Caryl

AU - Labbe, Ivo

AU - Magdis, Georgios

AU - Van Dokkum, Pieter

PY - 2008/2/10

Y1 - 2008/2/10

N2 - We investigate the stellar populations of a sample of 162 Lyα-emitting galaxies (LAEs) at z = 3.1 in the Extended Chandra Deep Field South, using deep Spitzer IRAC data available from the GOODS and SIMPLE surveys to derive reliable stellar population estimates. We divide the LAEs according to their rest-frame near-IR luminosities into IRAC-detected and IRAC-undetected samples. About 70% of the LAEs are undetected in 3.6 μm down to m 3.6 = 25.2 AB. Stacking analysis reveals that the average stellar population of the IRAC-undetected sample has an age of ∼200 Myr and a mass of ∼3 × 108 M⊙, consistent with the expectation that LAEs are mostly young and low-mass galaxies. On the other hand, the IRAC-detected LAEs are on average significantly older and more massive, with an average age ≳1 Gyr and mass ∼1010M⊙. Comparing the IRAC colors and magnitudes of the LAEs to z ∼ 3 Lyman break galaxies (LBGs) shows that the IRAC-detected LAEs lie at the faint blue end of the LBG color-magnitude distribution, suggesting that IRAC-detected LAEs may be the low-mass extension of the LBG population. We also present tentative evidence for a small fraction (∼5%) of obscured AGNs within the LAE sample. Our results suggest that LAEs posses a wide range of ages and masses. In addition, the presence of evolved stellar populations inside LAEs suggests that the Lyα-luminous phase of galaxies may be either a long-lasting or recurring phenomenon.

AB - We investigate the stellar populations of a sample of 162 Lyα-emitting galaxies (LAEs) at z = 3.1 in the Extended Chandra Deep Field South, using deep Spitzer IRAC data available from the GOODS and SIMPLE surveys to derive reliable stellar population estimates. We divide the LAEs according to their rest-frame near-IR luminosities into IRAC-detected and IRAC-undetected samples. About 70% of the LAEs are undetected in 3.6 μm down to m 3.6 = 25.2 AB. Stacking analysis reveals that the average stellar population of the IRAC-undetected sample has an age of ∼200 Myr and a mass of ∼3 × 108 M⊙, consistent with the expectation that LAEs are mostly young and low-mass galaxies. On the other hand, the IRAC-detected LAEs are on average significantly older and more massive, with an average age ≳1 Gyr and mass ∼1010M⊙. Comparing the IRAC colors and magnitudes of the LAEs to z ∼ 3 Lyman break galaxies (LBGs) shows that the IRAC-detected LAEs lie at the faint blue end of the LBG color-magnitude distribution, suggesting that IRAC-detected LAEs may be the low-mass extension of the LBG population. We also present tentative evidence for a small fraction (∼5%) of obscured AGNs within the LAE sample. Our results suggest that LAEs posses a wide range of ages and masses. In addition, the presence of evolved stellar populations inside LAEs suggests that the Lyα-luminous phase of galaxies may be either a long-lasting or recurring phenomenon.

KW - Cosmology: observations

KW - Galaxies: evolution

KW - Galaxies: high-redshift

KW - Galaxies: stellar content

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U2 - 10.1086/524702

DO - 10.1086/524702

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