Similarities and uniqueness of Ly a emitters among star-forming galaxies at z = 2.5

Rhythm Shimakawa, Tadayuki Kodama, Takatoshi Shibuya, Nobunari Kashikawa, Ichi Tanaka, Yuichi Matsuda, Ken ichi Tadaki, Yusei Koyama, Masao Hayashi, Tomoko L. Suzuki, Moegi Yamamoto

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


We conducted a deep narrow-band imaging survey with the Subaru Prime Focus Camera on the Subaru Telescope and constructed a sample of Lyα emitters (LAEs) at z = 2.53 in the UDS-CANDELS field, where a sample of Ha emitters (HAEs) at the same redshift is already obtained from our previous narrow-band observation at near-infrared. The deep narrow-band and multibroad-band data allow us to find LAEs of stellar masses and star formation rates (SFRs) down to ≳108 M and ≳0.2 M yr-1, respectively. We show that the LAEs are located along the same mass-SFR sequence traced by normal star-forming galaxies such as HAEs, but towards a significantly lower mass regime. Likewise, LAEs seem to share the same mass-size relation with typical star-forming galaxies, except for the massive LAEs that tend to show significantly compact sizes. We identify a vigorous mass growth in the central part of LAEs: the stellar mass density in the central region of LAEs increases as their total galaxy mass grows. On the other hand, we see no Lyα line in emission for most of the HAEs. Rather, we find that the Lyα feature is either absent or in absorption (Lyα absorbers, LAAs), and its absorption strength may increase with reddening of the UV continuum slope.We demonstrate that a deep Lyα narrow-band imaging like this study is able to search for not only LAEs but also LAAs in a certain redshift slice. This work suggests that LAEs trace normal starforming galaxies in the low-mass regime, while they remain as a unique population because the majority of HAEs are not LAEs.

Original languageEnglish
Pages (from-to)1123-1141
Number of pages19
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 2017 Jun 11
Externally publishedYes


  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: high-redshift

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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