Abstract
We present the spectrum of the galaxy companion to the z = 4.7 quasar BR 1202-0725 in the optical range 6000–9000 A, corresponding to 1050–1580 A in the rest frame. We detect a strong Lyα emission line at z = 4.702, with an integrated flux of 2 × 10-16 ergs cm-2 s-1, and a UV continuum longward of the Lyα emission at a flux level of 3 × 10-19 ergs cm-2 s-1 A-1. We fail to detect any C IV λ1550 emission with a 3 σ upper limit of 3 × 10-17 ergs cm-2 s-1. We show that the ratio between Lyα and continuum intensity and the absence of strong C IV emission imply that the UV continuum radiation is the result of intense star formation activity rather than of reprocessing of the QSO flux. The total estimated star formation rate of this z = 4.7 star-forming region is ~15–54 M⊙ yr-1, depending on the initial mass function and the metallicity. The present data suggest that the Lyα emission has a velocity and spatial structure, with possible velocity differences of 500 km s-1 on scales of a few kiloparsecs. These velocity patterns may be a signature of collapsing or merging phenomena in the QSO and its environment, as expected from current models of galaxy formation at high z.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
