A Redshift z = 5.4 Lyman-alpha emitting galaxy with linear morphology in the GRAPES/UDF field

Aug, 2004
11 pages
Published in:
  • Astrophys.J. 621 (2005) 582-586
e-Print:

Citations per year

20052008201120142017012345
Abstract: (arXiv)
We have discovered an extended Lyman alpha plume associated with a compact source at redshift 5.4 in slitless spectroscopic data from the Grism ACS Program for Extragalactic Science (GRAPES) project. The spatial extent of the emission is about 6 x 1.5 kpc (1 x 0.25 arcsec). Combining our grism data and the broadband images from the Hubble UltraDeep Field (UDF) images, we find a Lyman alpha line flux of 2e-17 erg/cm2/s and surface brightness 7e-17 erg/cm2/s/arcsec2. The UDF images show diffuse continuum emission associated with the Lyman alpha plume (hereafter UDF 5225), with three embedded knots. The morphology of UDF 5225 is highly suggestive of a galaxy in assembly. It is moreover possible that the prominent Lyman alpha emission from this object is due to an active nucleus, and that we are seeing the simultaneous growth through accretion of a galaxy and its central black hole. Followup observations at higher spectral resolution could test this hypothesis.
  • galaxies: formation
  • galaxies: high-redshift
  • galaxies: individual (UDF 5225)
  • galaxies: interactions
  • galaxies: starburst