Weak line quasars at high redshift: Extremely high accretion rates or anemic broad-line regions?

Ohad Shemmer, Benny Trakhtenbrot, Scott F. Anderson, W. N. Brandt, Aleksandar M. Diamond-Stanic, Xiaohui Fan, Paulina Lira, Hagai Netzer, Richard M. Plotkin, Gordon T. Richards, Donald P. Schneider, Michael A. Strauss

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Abstract

We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad Hβ line and place tight upper limits on the strengths of their [Oiii] lines. Virial, Hβ-based black hole mass determinations indicate normalized accretion rates of L/LEdd= 0 .4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts.We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of Γ = 1.91 -0.22+0.24, which supports the virial L/LEdd determination in this source. Our results suggest that theweakness of the broad emission lines inWLQsis not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.

Original languageEnglish (US)
Pages (from-to)L152-L156
JournalAstrophysical Journal Letters
Volume722
Issue number2 PART 2
DOIs
StatePublished - Oct 20 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Shemmer, O., Trakhtenbrot, B., Anderson, S. F., Brandt, W. N., Diamond-Stanic, A. M., Fan, X., Lira, P., Netzer, H., Plotkin, R. M., Richards, G. T., Schneider, D. P., & Strauss, M. A. (2010). Weak line quasars at high redshift: Extremely high accretion rates or anemic broad-line regions? Astrophysical Journal Letters, 722(2 PART 2), L152-L156. https://doi.org/10.1088/2041-8205/722/2/L152