Constraining the LYα escape fraction with far-infrared observations of LYα emitters

Julie L. Wardlow, S. Malhotra, Z. Zheng, S. Finkelstein, J. Bock, C. Bridge, J. Calanog, Robin Bruce Ciardullo, A. Conley, A. Cooray, D. Farrah, E. Gawiser, Caryl Ann Gronwall, S. Heinis, E. Ibar, R. J. Ivison, G. Marsden, S. J. Oliver, J. Rhoads, D. Riechers & 5 others B. Schulz, A. J. Smith, M. Viero, L. Wang, M. Zemcov

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Abstract

We study the far-infrared properties of 498 Lyα emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 μm data from the Herschel Multi-tiered Extragalactic Survey and 870 μm data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1σ depths of ̃0.1 to 0.4 mJy. The LAEs are also undetected at ≥3σ in the stacks, although a 2.5σ signal is observed at 870 μm for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Lyα and UV emission to determine lower limits on the LAEs' Lyα escape fraction (f esc (Lyα)). For the Sd SED template, the inferred LAEs f esc (Lyα) are ≳ 30% (1σ) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f esc (Lyα) at these redshifts. Thus, if the LAEs f esc (Lyα) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f esc (Lyα) of ̃10%-20% (1σ), all of which are slightly higher than the global evolution of f esc (Lyα), but consistent with it at the 2σ-3σ level.

Original languageEnglish (US)
Article number9
JournalAstrophysical Journal
Volume787
Issue number1
DOIs
StatePublished - May 20 2014

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spectral energy distribution
escape
emitters
templates
star formation rate
energy
galaxies
stacking
luminosity
probe
distribution
probes
rate

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Wardlow, J. L., Malhotra, S., Zheng, Z., Finkelstein, S., Bock, J., Bridge, C., ... Zemcov, M. (2014). Constraining the LYα escape fraction with far-infrared observations of LYα emitters. Astrophysical Journal, 787(1), [9]. https://doi.org/10.1088/0004-637X/787/1/9
Wardlow, Julie L. ; Malhotra, S. ; Zheng, Z. ; Finkelstein, S. ; Bock, J. ; Bridge, C. ; Calanog, J. ; Ciardullo, Robin Bruce ; Conley, A. ; Cooray, A. ; Farrah, D. ; Gawiser, E. ; Gronwall, Caryl Ann ; Heinis, S. ; Ibar, E. ; Ivison, R. J. ; Marsden, G. ; Oliver, S. J. ; Rhoads, J. ; Riechers, D. ; Schulz, B. ; Smith, A. J. ; Viero, M. ; Wang, L. ; Zemcov, M. / Constraining the LYα escape fraction with far-infrared observations of LYα emitters. In: Astrophysical Journal. 2014 ; Vol. 787, No. 1.
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abstract = "We study the far-infrared properties of 498 Lyα emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 μm data from the Herschel Multi-tiered Extragalactic Survey and 870 μm data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1σ depths of ̃0.1 to 0.4 mJy. The LAEs are also undetected at ≥3σ in the stacks, although a 2.5σ signal is observed at 870 μm for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Lyα and UV emission to determine lower limits on the LAEs' Lyα escape fraction (f esc (Lyα)). For the Sd SED template, the inferred LAEs f esc (Lyα) are ≳ 30{\%} (1σ) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f esc (Lyα) at these redshifts. Thus, if the LAEs f esc (Lyα) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f esc (Lyα) of ̃10{\%}-20{\%} (1σ), all of which are slightly higher than the global evolution of f esc (Lyα), but consistent with it at the 2σ-3σ level.",
author = "Wardlow, {Julie L.} and S. Malhotra and Z. Zheng and S. Finkelstein and J. Bock and C. Bridge and J. Calanog and Ciardullo, {Robin Bruce} and A. Conley and A. Cooray and D. Farrah and E. Gawiser and Gronwall, {Caryl Ann} and S. Heinis and E. Ibar and Ivison, {R. J.} and G. Marsden and Oliver, {S. J.} and J. Rhoads and D. Riechers and B. Schulz and Smith, {A. J.} and M. Viero and L. Wang and M. Zemcov",
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Wardlow, JL, Malhotra, S, Zheng, Z, Finkelstein, S, Bock, J, Bridge, C, Calanog, J, Ciardullo, RB, Conley, A, Cooray, A, Farrah, D, Gawiser, E, Gronwall, CA, Heinis, S, Ibar, E, Ivison, RJ, Marsden, G, Oliver, SJ, Rhoads, J, Riechers, D, Schulz, B, Smith, AJ, Viero, M, Wang, L & Zemcov, M 2014, 'Constraining the LYα escape fraction with far-infrared observations of LYα emitters', Astrophysical Journal, vol. 787, no. 1, 9. https://doi.org/10.1088/0004-637X/787/1/9

Constraining the LYα escape fraction with far-infrared observations of LYα emitters. / Wardlow, Julie L.; Malhotra, S.; Zheng, Z.; Finkelstein, S.; Bock, J.; Bridge, C.; Calanog, J.; Ciardullo, Robin Bruce; Conley, A.; Cooray, A.; Farrah, D.; Gawiser, E.; Gronwall, Caryl Ann; Heinis, S.; Ibar, E.; Ivison, R. J.; Marsden, G.; Oliver, S. J.; Rhoads, J.; Riechers, D.; Schulz, B.; Smith, A. J.; Viero, M.; Wang, L.; Zemcov, M.

In: Astrophysical Journal, Vol. 787, No. 1, 9, 20.05.2014.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Constraining the LYα escape fraction with far-infrared observations of LYα emitters

AU - Wardlow, Julie L.

AU - Malhotra, S.

AU - Zheng, Z.

AU - Finkelstein, S.

AU - Bock, J.

AU - Bridge, C.

AU - Calanog, J.

AU - Ciardullo, Robin Bruce

AU - Conley, A.

AU - Cooray, A.

AU - Farrah, D.

AU - Gawiser, E.

AU - Gronwall, Caryl Ann

AU - Heinis, S.

AU - Ibar, E.

AU - Ivison, R. J.

AU - Marsden, G.

AU - Oliver, S. J.

AU - Rhoads, J.

AU - Riechers, D.

AU - Schulz, B.

AU - Smith, A. J.

AU - Viero, M.

AU - Wang, L.

AU - Zemcov, M.

PY - 2014/5/20

Y1 - 2014/5/20

N2 - We study the far-infrared properties of 498 Lyα emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 μm data from the Herschel Multi-tiered Extragalactic Survey and 870 μm data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1σ depths of ̃0.1 to 0.4 mJy. The LAEs are also undetected at ≥3σ in the stacks, although a 2.5σ signal is observed at 870 μm for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Lyα and UV emission to determine lower limits on the LAEs' Lyα escape fraction (f esc (Lyα)). For the Sd SED template, the inferred LAEs f esc (Lyα) are ≳ 30% (1σ) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f esc (Lyα) at these redshifts. Thus, if the LAEs f esc (Lyα) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f esc (Lyα) of ̃10%-20% (1σ), all of which are slightly higher than the global evolution of f esc (Lyα), but consistent with it at the 2σ-3σ level.

AB - We study the far-infrared properties of 498 Lyα emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 μm data from the Herschel Multi-tiered Extragalactic Survey and 870 μm data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1σ depths of ̃0.1 to 0.4 mJy. The LAEs are also undetected at ≥3σ in the stacks, although a 2.5σ signal is observed at 870 μm for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Lyα and UV emission to determine lower limits on the LAEs' Lyα escape fraction (f esc (Lyα)). For the Sd SED template, the inferred LAEs f esc (Lyα) are ≳ 30% (1σ) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f esc (Lyα) at these redshifts. Thus, if the LAEs f esc (Lyα) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f esc (Lyα) of ̃10%-20% (1σ), all of which are slightly higher than the global evolution of f esc (Lyα), but consistent with it at the 2σ-3σ level.

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Wardlow JL, Malhotra S, Zheng Z, Finkelstein S, Bock J, Bridge C et al. Constraining the LYα escape fraction with far-infrared observations of LYα emitters. Astrophysical Journal. 2014 May 20;787(1). 9. https://doi.org/10.1088/0004-637X/787/1/9