Weak Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-line Regions?

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...

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Published inAstrophysical journal. Letters Vol. 722; no. 2; pp. L152 - L156
Main Authors Shemmer, Ohad, Trakhtenbrot, Benny, Anderson, Scott F, Brandt, W. N, Diamond-Stanic, Aleksandar M, Fan, Xiaohui, Lira, Paulina, Netzer, Hagai, Plotkin, Richard M, Richards, Gordon T, Schneider, Donald P, Strauss, Michael A
Format Journal Article
LanguageEnglish
Published United States IOP Publishing 20.10.2010
Subjects
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
BLACK HOLES
BOSONS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION
GALAXIES
GALAXY NUCLEI
HARD X RADIATION
IONIZING RADIATIONS
LUMINOSITY
MASS
MASSLESS PARTICLES
OPTICAL PROPERTIES
PHOTONS
PHYSICAL PROPERTIES
QUASARS
RADIATIONS
RED SHIFT
SPECTROSCOPY
ULTRAVIOLET RADIATION
X RADIATION
X-RAY GALAXIES
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Summary: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 H Delta *b line and place tight upper limits on the strengths of their [O III] lines. Virial, H Delta *b-based black hole mass determinations indicate normalized accretion rates of L/L Edd=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 Delta *G = 1.91+0.24 --0.22, which supports the virial L/L Edd determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.
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ISSN:2041-8205
2041-8213
DOI:10.1088/2041-8205/722/2/L152