Rest-Frame Ultraviolet to Near-Infrared Observations of an Interacting Lyman Break Galaxy at z = 4.42 Academic Article uri icon


  • We present the rest-frame ultraviolet through near-infrared spectral energy distribution for an interacting Lyman break galaxy at a redshift z = 4.42, the highest redshift merging system known with clearly resolved tidal features. The two objects in this system, HDF-G4 and its previously unidentified companion, are both B435 -band dropouts, have similar V606 - i 775 and i775 - z850 colors, and are separated by 1, which at z = 4.42 corresponds to 7 kpc projected nuclear separation; these are all indicators of an interacting system. Fits to stellar population models indicate a stellar mass of M* = 2.6 10 10M, an age of * = 720 Myr, and an exponential star formation history, with an e-folding time 0 = 440 Myr. Using these derived stellar populations as constraints, we model the HDF-G4 system using hydrodynamical simulations, and find that it will likely evolve into a quasar by z 3.5, and a quiescent, compact spheroid by z 2.5, similar to those observed at z 2. The existence of such an object supports galaxy formation models in which major mergers drive the high-redshift buildup of spheroids and black holes. 2007. The American Astronomical Society. All rights reserved.

published proceedings

  • The Astrophysical Journal

author list (cited authors)

  • Younger, J. D., Huang, J., Fazio, G. G., Cox, T. J., Lai, K., Hopkins, P. F., ... Shapley, A. E.

citation count

  • 5

complete list of authors

  • Younger, Joshua D||Huang, Jia-Sheng||Fazio, Giovanni G||Cox, Thomas J||Lai, Kamson||Hopkins, Philip F||Hernquist, Lars||Papovich, Casey J||Simard, Luc||Lin, Lihwai||Cheng, Yi-Wen||Yan, Haojin||Kereš, Dušan||Shapley, Alice E

publication date

  • December 2007