Spatially resolved HST grism spectroscopy of a lensed emission line galaxy at z ∼ 1

Brenda Louise Frye, Mairead Hurley, David V. Bowen, Gerhardt Meurer, Keren Sharon, Amber Straughn, Dan Coe, Tom Broadhurst, Puragra Guhathakurta

Research output: Contribution to journalArticle

13 Scopus citations


We take advantage of gravitational lensing amplification by A1689 (z = 0.187) to undertake the first space-based census of emission line galaxies (ELGs) in the field of a massive lensing cluster. Forty-three ELGs are identified to a flux of i 775 = 27.3 via slitless grism spectroscopy. One ELG (at z = 0.7895) is very bright owing to lensing magnification by a factor of ≈4.5. Several Balmer emission lines (ELs) detected from ground-based follow-up spectroscopy signal the onset of a major starburst for this low-mass galaxy (M* ≈ 2 × 109 M ) with a high specific star formation rate (≈20Gyr -1). From the blue ELs we measure a gas-phase oxygen abundance consistent with solar (12+log(O/H) = 8.8 ± 0.2). We break the continuous line-emitting region of this giant arc into seven ∼1kpc bins (intrinsic size) and measure a variety of metallicity-dependent line ratios. A weak trend of increasing metal fraction is seen toward the dynamical center of the galaxy. Interestingly, the metal line ratios in a region offset from the center by ∼1kpc have a placement on the blue H II region excitation diagram with f ([O III])/f(Hβ) and f ([Ne III])/f(Hβ) that can be fitted by an active galactic nucleus (AGN). This asymmetrical AGN-like behavior is interpreted as a product of shocks in the direction of the galaxy's extended tail, possibly instigated by a recent galaxy interaction.

Original languageEnglish (US)
Article number17
JournalAstrophysical Journal
Issue number1
Publication statusPublished - Jul 20 2012



  • cosmology: observations
  • galaxies: clusters: general
  • galaxies: clusters: individual (A1689)
  • galaxies: distances and redshifts
  • galaxies: fundamental parameters

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Frye, B. L., Hurley, M., Bowen, D. V., Meurer, G., Sharon, K., Straughn, A., ... Guhathakurta, P. (2012). Spatially resolved HST grism spectroscopy of a lensed emission line galaxy at z ∼ 1. Astrophysical Journal, 754(1), [17].