SDSS J1553+0056: A BALQSO mimicking a Lyman-break galaxy

¹ Landessternwarte, Königstuhl, 69117 Heidelberg, Germany e-mail: I.Appenzeller@lsw.uni-heidelberg.de
² Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr., 85741 Garching, Germany

Received: 13 December 2004
Accepted: 12 January 2005

Abstract

Using the UVES echelle spectrograph at the ESO VLT we obtained high-resolution () spectra of the object SDSS J1553+0056, which has been identified in the literature alternatively as a high-redshift quasar or as a Lyman-break galaxy (LBG). Although low-resolution spectra of SDSS J1553+0056 closely resemble those of LBGs, our high-resolution spectra allow us to identify this object unambiguously as a LoBAL quasar, probably belonging to the rare FeLoBALQSO class. Based on our spectrum we discuss how misidentifications of such objects from low-resolution spectra can be avoided.