Lyα-emitting galaxies at redshift z ∼ 4.5 in the lala cetus field

Jun Xian Wang, Sangeeta Malhotra, James E. Rhoads, Hao Tong Zhang, Steven L. Finkelstein

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

We present a large sample of Lyα-emitting galaxies (LAEs) spectroscopically confirmed at redshift z ≈ 4.5, based on Inamori-Magellan Areal Camera and Spectrograph spectroscopic observations of candidate z ≈ 4.5 Lyα-emitting galaxies in the large area Lyman alpha (LALA) narrowband imaging survey Cetus field. We identify 110 of them as z ≈ 4.5 Lyα emitters based on single-line detections with no continuum emission blueward of the line. Six foreground galaxies are identified, either based on multiple lines or blueward continuum emission. The Lyα confirmation rate varies from <50% to 76% for candidates selected in different narrowband filters at slightly different redshifts. We find a drop in the LAE density at redshift 4.50 ± 0.03 from redshift 4.39 to 4.47 by a factor of 66%, which could be a large-scale void in the distribution of star-forming galaxies (∼18 Mpc along the line of sight and ∼80 Mpc across). The sample includes many objects with equivalent widths (EWs) ≳200. These large EW candidates are spectroscopically confirmed at the same rate as candidates with more modest EWs. A composite spectrum of all 110 confirmed LAEs shows the characteristic asymmetry of the Lyα line. It also places new and stringent upper limits on the C IV 1549 /Lyα and He II 1640 /Lyα line ratios, providing a new upper limit on the fraction of active galactic nuclei in Lyα selected galaxy samples, and on the contribution of Pop III populations. Finally, we calculate the Lyα luminosity function for our z ≈ 4.5 sample, which is consistent with those at other redshifts, showing that there is no evolution in Lyα luminosity function from z = 3.1 to 6.6.

Original languageEnglish (US)
Pages (from-to)762-771
Number of pages10
JournalAstrophysical Journal
Volume706
Issue number1
DOIs
StatePublished - 2009

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galaxies
void
field survey
asymmetry
filter
narrowband
luminosity
continuums
rate
active galactic nuclei
line of sight
spectrographs
voids
emitters
cameras
filters
stars
composite materials
detection
distribution

Keywords

  • Cosmology: Observations
  • Early universe
  • Galaxies: Evolution
  • Galaxies: Formation
  • Galaxies: High-redshift

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Wang, J. X., Malhotra, S., Rhoads, J. E., Zhang, H. T., & Finkelstein, S. L. (2009). Lyα-emitting galaxies at redshift z ∼ 4.5 in the lala cetus field. Astrophysical Journal, 706(1), 762-771. https://doi.org/10.1088/0004-637X/706/1/762

Lyα-emitting galaxies at redshift z ∼ 4.5 in the lala cetus field. / Wang, Jun Xian; Malhotra, Sangeeta; Rhoads, James E.; Zhang, Hao Tong; Finkelstein, Steven L.

In: Astrophysical Journal, Vol. 706, No. 1, 2009, p. 762-771.

Research output: Contribution to journalArticle

Wang, JX, Malhotra, S, Rhoads, JE, Zhang, HT & Finkelstein, SL 2009, 'Lyα-emitting galaxies at redshift z ∼ 4.5 in the lala cetus field', Astrophysical Journal, vol. 706, no. 1, pp. 762-771. https://doi.org/10.1088/0004-637X/706/1/762
Wang, Jun Xian ; Malhotra, Sangeeta ; Rhoads, James E. ; Zhang, Hao Tong ; Finkelstein, Steven L. / Lyα-emitting galaxies at redshift z ∼ 4.5 in the lala cetus field. In: Astrophysical Journal. 2009 ; Vol. 706, No. 1. pp. 762-771.
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KW - Galaxies: High-redshift

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