Black Hole Masses and Enrichment of z ~ 6 SDSS Quasars

By J. Kurk, F. Walter, Xiaohui Fan, Linhua Jiang, D. Riechers, Hans-Walter Rix, L. Pentericci, M. Strauss, C. Carilli, S. Wagner. 2007

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We present sensitive near-infrared spectroscopic observations for a sample of five z ~ 6 quasars. These quasars are among the most distant, currently known quasars in the universe. The spectra have been obtained using ISAAC at the VLT and include the C IV, Mg II, and Fe II lines. We measure the Fe II/Mg II line ratio, as an observational proxy for the Fe/α-element ratio. We derive a ratio of 2.7 ± 0.8 for our sample, which is similar to that found for lower redshift quasars; i.e., we provide additional evidence for the lack of evolution in the Fe II/Mg II line ratio of quasars up to the highest redshifts. This result demonstrates that star formation must have commenced at z ≥ 8 in the quasar hosts. The line widths of the Mg II and C IV lines give two estimates for the black hole masses. A third estimate is given by assuming that the quasars emit at their Eddington luminosity. The derived masses using these three methods agree well, implying that the quasars are not likely to be strongly lensed. We derive central black hole masses of (0.3-5.2) × 109 M☉. We use the difference between the redshift of Mg II (a proxy for the systemic redshift of the quasar) and the onset of the Gunn-Peterson trough to derive the extent of the ionized Strömgren spheres around our target quasars. The derived physical radii are about 5 Mpc. Using a simple ionization model, the emission of the central quasars would need of order 106-108 yr to create these cavities. As the e-folding timescale for the central accreting black hole is on the order of a few times 107 yr, it can grow by one e-folding or less within this time span.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/8f67b82ba762cba6be98fd79f85e6ca58a860ab5

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Citations in the corpus

BLACK HOLE MASS ESTIMATES AND EMISSION-LINE PROPERTIES OF A SAMPLE OF REDSHIFT z > 6.5 QUASARS (2013, background): “Therefore, for these objects, we assume that the Mg ii emission line (which is a low ionization line) as a proxy of the quasar systemic redshift (see also Jiang et al. 2007; Kurk et al. 2007; De Rosa et al. 2011).”
A SURVEY OF z ∼ 6 QUASARS IN THE SLOAN DIGITAL SKY SURVEY DEEP STRIPE. I. A FLUX-LIMITED SAMPLE AT zAB < 21 (2007, background): “…Germany 10 Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 the Eddington limit (e.g. Barth et al. 2003; Vestergaard 2004; Jiang et al. 2006a; Kurk et al. 2007), revealing the rapid growth of central BHs at high redshift.”
A SURVEY OF z ∼ 6 QUASARS IN THE SLOAN DIGITAL SKY SURVEY DEEP STRIPE. II. DISCOVERY OF SIX QUASARS AT zAB>21 (2009, background): “In luminous z ∼ 6 quasars black hole masses measured in this way are usually several billion solar masses (e.g. Jiang et al. 2007; Kurk et al. 2007).”
Black Hole Growth to z = 2 - I: Improved Virial Methods for Measuring M_BH and L/L_Edd (2012, methodology): “Thesesystems could have grown to be the most massive BHs known (MBH ∼ 1010M⊙) as early asz ∼ 4 (Willott et al. 2010; Kurk et al. 2007; De Rosa et al. 2011; Trakhtenbrot et al. 2011, hereafter T11).”
DISCOVERY OF THREE z > 6.5 QUASARS IN THE VISTA KILO-DEGREE INFRARED GALAXY (VIKING) SURVEY (2013, background): “These black hole masses are very similar to those powering quasars at z ∼ 6 that were discovered in the SDSS main survey (e.g., Jiang et al. 2007; Kurk et al. 2007; De Rosa et al. 2011), but generally more massive than those of the z ∼ 6 quasars discovered in the CFHQS (Willott et al. 2010a).”
Biases in Virial Black Hole Masses: An SDSS Perspective (2007, background): “…obtain near-IR spectra for high-redshift quasars with optical spectra, toget Hβ or MgII measurements (e.g., Sulentic et al. 2006; Jiang et al. 2007a; Kurk et al. 2007; Netzer et al. 2007), since the CIV virial estimator alone is perhaps questionable for the reasons we have discussed in this paper.”
THE PAN-STARRS1 DISTANT z > 5.6 QUASAR SURVEY: MORE THAN 100 QUASARS WITHIN THE FIRST GYR OF THE UNIVERSE (2016, unknown): “…Mahabal et al. (2005), (7) Cool et al. (2006), (8) Fan et al. (2006), (9) Goto (2006), (10) McGreer et al. (2006), (11) Carilli et al. (2007), (12) Kurk et al. (2007), (13) Stern et al. (2007), (14) Venemans et al. (2007), (15) Willott et al. (2007), (16) Jiang et al. (2008), (17) Wang et al.…”
EVIDENCE FOR NON-EVOLVING Fe ii/Mg ii RATIOS IN RAPIDLY ACCRETING z ∼ 6 QSOs (2011, methodology): “Only few faint QSOs (z′AB > 20) have measured MBH to date: two from the SDSS deep Stripe 82 (Jiang et al. 2008, 2009; Kurk et al. 2007, 2009), a deep imaging survey obtained by repeatedly scanning a stripe (260 deg2) along the celestial equator, and nine from CFHQS (Willott et al. 2010).”
STAR FORMATION AND GAS KINEMATICS OF QUASAR HOST GALAXIES AT z ∼ 6: NEW INSIGHTS FROM ALMA (2013, background): “…et al. 2009, 2011; and the Panoramic Survey Telescope and Rapid Response System [Pan-STARRS], Morganson et al. 2012) with optical z-band magnitudes from 18.8 to 24.4 and inferred SMBH masses from 108 to a few 109 M (Kurk et al. 2007; Jiang et al. 2007; Willott et al. 2010; De Rosa et al. 2011).”
EDDINGTON-LIMITED ACCRETION AND THE BLACK HOLE MASS FUNCTION AT REDSHIFT 6 (2010, methodology): “Using this method it has been possible to measure black hole masses for SDSS quasars at z = 6 (Willott et al. 2003; Jiang et al. 2007; Kurk et al. 2007; Kurk et al. 2009).”
Physical Properties of 15 Quasars at z ≳ 6.5 (2017, methodology): “6.4 (observations collected from several studies: Iwamuro et al. 2002, 2004, Barth et al. 2003, Jiang et al. 2007, Kurk et al. 2007, 2009); Willott et al. (2010b) present data for nine lower luminosity (Lbol < 10 47 erg s−1) z ∼ 6 quasars; finally, Wu et al. (2015) publish an ultra luminous quasar…”
THE FINAL SDSS HIGH-REDSHIFT QUASAR SAMPLE OF 52 QUASARS AT z > 5.7 (2016, background): “…shows that these luminous quasars harbor billion-solar-mass black holes and emit near the Eddington limit, suggesting the rapid growth of central black holes at this early epoch (e.g., Jiang et al. 2007; Kurk et al. 2007; Willott et al. 2010a; De Rosa et al. 2014; Jun et al. 2015; Wu et al. 2015).”