Grecco A. Oyarzún, Guillermo A. Blanc, Valentino González, Mario Mateo, John I. Bailey, Steven L. Finkelstein, Paulina Lira, Jeffrey D. Crane, Edward W. Olszewski

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


In this work, we show how the stellar mass (M∗) of galaxies affects the 3 < z < 4.6 Lyα equivalent width (EW) distribution. To this end, we design a sample of 629 galaxies in the M∗ range 7.6 < log M∗/M < 10.6 from the 3D-HST/CANDELS survey. We perform spectroscopic observations of this sample using the Michigan/Magellan Fiber System, allowing us to measure Lyα fluxes and use 3D-HST/CANDELS ancillary data. In order to study the Lyα EW distribution dependence on M∗, we split the whole sample in three stellar mass bins. We find that, in all bins, the distribution is best represented by an exponential profile of the form dN (M∗)/dEW = W0(M∗)-1A(M∗)e-EW/W0(M∗). Through a Bayesian analysis, we confirm that lower M∗ galaxies have higher Lyα EWs. We also find that the fraction A of galaxies featuring emission and the e-folding scale W0 of the distribution anti-correlate with M∗, recovering expressions of the forms A(M∗) = -0.26(.13)log M∗/M + 3.01(1.2) and W0(M∗) = - 15.6(3.5)log M∗/M + 166(34). These results are crucial for proper interpretation of Lyα emission trends reported in the literature that may be affected by strong M∗ selection biases.

Original languageEnglish (US)
Article numberL14
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Apr 10 2016


  • galaxies: evolution
  • galaxies: high-redshift
  • galaxies: statistics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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