Evidence for Spatially Compact Lyα Emission in z = 3.1 Lyα-emitting Galaxies
Abstract
We present the results of a high spatial resolution study of the line emission in a sample of z = 3.1 Lyα-emitting galaxies (LAEs) in the Extended Chandra Deep Field-South. Of the eight objects with coverage in our HST/WFPC2 narrowband imaging, two have clear detections and two are barely detected (~2 σ). The clear detections are within ~0.5 kpc of the centroid of the corresponding rest-UV continuum source, suggesting that the line-emitting gas and young stars in LAEs are spatially coincident. The brightest object exhibits extended emission with a half-light radius of ~1.5 kpc, but a stack of the remaining LAE surface brightness profiles is consistent with the WFPC2 point-spread function. This suggests that the Lyα emission in these objects originates from a compact (lsim2 kpc) region and cannot be significantly more extended than the far-UV continuum emission (lsim1 kpc). Comparing our WFPC2 photometry to previous ground-based measurements of their monochromatic fluxes, we find at 95% (99.7%) confidence that we cannot be missing more than 22% (32%) of the Lyα emission.
Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Institute. STScI is operated by the association of Universities for Research in Astronomy, Inc., under the NASA contract NAS 5-26555.- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2010
- DOI:
- 10.1088/2041-8205/716/2/L200
- arXiv:
- arXiv:1002.2432
- Bibcode:
- 2010ApJ...716L.200B
- Keywords:
-
- cosmology: observations;
- galaxies: formation;
- galaxies: high-redshift;
- galaxies: structure;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 4 pages, 3 figures, accepted to ApJ letters