Spitzer observations of high-redshift QSOs

Dean C. Hines, O. Krause, G. H. Rieke, X. Fan, M. Blaylock, G. Neugebauer

Research output: Contribution to journalReview articlepeer-review

21 Scopus citations


We have observed 13 z ≥ 4.5 QSOs using the Multiband Imaging Photometer for Spitzer, nine of which were also observed with the Infrared Array Camera. The observations probe rest wavelengths ∼0.6-4.3 μm, bracketing the local minimum in QSO spectral energy distributions (SEDs) between strong optical emission associated directly with accretion processes and thermal emission from hot dust heated by the central engine. The new Spitzer photometry combined with existing measurements at other wavelengths shows that the SEDs of high-redshift QSOs (z ≥ 4.5) do not differ significantly from typical QSOs of similar luminosity at lower redshifts (z ≲ 2). This behavior supports other indications that all the emission components and physical structures that characterize QSO activity can be established by z = 6.4. The similarity also suggests that some QSOs at high redshift will be very difficult to identify because they are viewed along dust-obscured sight lines.

Original languageEnglish (US)
Pages (from-to)L85-L88
JournalAstrophysical Journal
Issue number2 II
StatePublished - Apr 20 2006


  • Galaxies: high-redshift
  • Infrared: galaxies
  • Quasars: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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