A Classic Type 2 QSO

By C. Norman, G. Hasinger, R. Giacconi, R. Gilli, Lisa J. Kewley, M. Nonino, Piero Rosati, G. Szokoly, P. Tozzi, Junxian Wang and 7 more. 2001

189 citations recorded by the source corpus.

In the Chandra Deep Field-South 1 Ms exposure, we have found, at redshift 3.700 ± 0.005, the most distant type 2 active galactic nucleus ever detected. It is the source with the hardest X-ray spectrum with redshift z > 3. The optical spectrum has no detected continuum emission to a 3 σ detection limit of ~3 × 10-19 ergs s-1 cm-2 Å-1 and shows narrow lines of Lyα, C IV, N V, He II, O VI, [O III], and C III]. Their FWHM line widths have a range of ~700-2300 km s-1 with an average of approximately ~1500 km s-1. The emitting gas is metal-rich (Z ≃ 2.5-3 Z☉). In the X-ray spectrum of 130 counts in the 0.5-7 keV band, there is evidence for intrinsic absorption with NH ≳ 1024 cm-2. An iron Kα line with rest-frame energy and equivalent width of ~6.4 keV and ~1 keV, respectively, in agreement with the obscuration scenario, is detected at a 2 σ level. If confirmed by our forthcoming XMM-Newton observations, this would be the highest redshift detection of Fe Kα. Depending on the assumed cosmology and the X-ray transfer model, the 2-10 keV rest frame luminosity corrected for absorption is ~1045 ± 0.5 ergs cm-2 s-1, which makes our source a classic example of the long-sought type 2 QSO. From standard population synthesis models, these sources are expected to account for a relevant fraction of the black hole-powered QSO distribution at high redshift.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d28a81e86844fe336d95a815cdb6c31bd2468d7a

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Citations in the corpus

Evidence for Quasar Activity Triggered by Galaxy Mergers in HST Observations of Dust-reddened Quasars (2007, background): “Optical quasar surveys tend to miss dust-reddened quasars which have been found either with infrared surveys (Cutri et al. 2001; Lacy et al. 2004), radio surveys (White et al. 2003), hard X-ray surveys (Norman et al. 2002), or surveys for high-ionization narrow-line objects (Zakamska et al. 2006).”
THE XMM-NEWTON WIDE-FIELD SURVEY IN THE COSMOS FIELD (XMM-COSMOS): DEMOGRAPHY AND MULTIWAVELENGTH PROPERTIES OF OBSCURED AND UNOBSCURED LUMINOUS ACTIVE GALACTIC NUCLEI (2010, background): “However, we note that the hybrid classification in Treister et al. (2009a) is used only for sources at z< 0.5, which translates to LX < 10 42.5 erg s−1 at the limiting flux of XMM-COSMOS sources, and LX < 10 43 erg s−1 at the limiting flux of the ECDFS sample, i.e. the first two bins in Fig.”
The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era (2006, background): “1021 cm−2) barely detectable in the X– ray band to extremely large columns able to efficiently absorb the X–ray emission up to 10 keV (NH & 1024 cm−2) are routinely observed for both local (Risaliti et al. 1999) and distant AGN (Norman et al. 2002, Tozzi et al. 2006, Mainieri et al. 2005).”
OBSCURATION-DEPENDENT EVOLUTION OF ACTIVE GALACTIC NUCLEI (2015, background): “Following a handful of early discoveries of Compton-thick AGN in deep X-ray surveys (Norman et al. 2002; Tozzi et al. 2006; Comastri et al. 2011), an important recent development has been the identification of significant samples of Compton-thick AGN at moderate to high redshifts (Brightman & Ueda…”
The FIRST-2MASS Red Quasar Survey (2007, background): “These sources are found to have high column densities (NH > 10 23 cm 2) and X-ray luminosities (LX > 1044 ergs s 1), as well as narrow permitted emission lines in their optical spectra and extremely weak optical continua (Norman et al. 2002; Stern et al. 2002).”
Chandra and Spitzer Unveil Heavily Obscured Quasars in the Chandra/SWIRE Survey (2006, background): “Other examples of Compton-thick AGNs at high z are the type 2 quasars, CXO 52 (z ¼ 3:288; Stern et al. 2002), CDFS 202 (z ¼ 3:700; Norman et al. 2002), and CDFS 263 (z ¼ 3:660; Mainieri et al. 2005).”
The Chandra Deep Field-South: Optical Spectroscopy. I. (2003, background): “Nine (þ4:1 3:0: 1 errors) of these sources are in the redshift range 2 < z < 4, and their optical spectra are dominated by strong, narrow high excitation UV permitted lines, very similar to the prototypical object CDFS SPECTROSCOPIC FOLLOW-UP 347No. 2, 2004 CDFS-202 (Norman et al. 2002).”
The HELLAS2XMM Survey. VII. The Hard X-Ray Luminosity Function of AGNs up to z = 4: More Absorbed AGNs at Low Luminosities and High Redshifts (2005, background): “A notable example has been reported by Norman et al. (2002).”
Obscured and Unobscured Active Galactic Nuclei in the Spitzer Space Telescope First Look Survey (2004, background): “The number of AGN missed in optical or soft X-ray surveys due to obscuring columns of dust and gas in the host is still an open question (e.g., Webster et al. 1995; Cutri et al. 2001; Gregg et al. 2003; Norman et al. 2002; Richards et al. 2003).”
Faint high-redshift AGN in the Chandra deep field south: the evolution of the AGN luminosity function and black hole demography (2011, background): “(a) L=Luo08, M=GOODS-MUSIC, MY=GOODS-MUSYC Cardamone et al. (2010); X=Xue11, G=Giacconi et al. (2002); (b) Gilli et al. (2011); (c) Norman et al. (2002); (d) Secondary solution at z < 0.5; (e) Luo08 z = 2.45; Luo08; ( f ) 2.71; (g) Luo08 z = 2.36; (h) Luo08 z > 7.4; (i) Just below detection…”
C IV λ1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei (2007, background): “Highand low-redshift type 2 AGNs with obvious C iv k1549NC emission have recently been found in significant numbers (Barger et al. 2002; Jarvis et al. 2005 ; Norman et al. 2002 ; Stern et al. 2002 ; Szokoly et al. 2004; Mainieri et al. 2005 ; Severgnini et al. 2006).”
Quasars: the characteristic spectrum and the induced radiative heating (2003, background): “We should mention that X-ray spectra exhibiting a low-energy exponential cutoff have been recently measured for several obscured quasars (Iwasawa, Fabian & Ettori 2001; Stern et al. 2002; Norman et al. 2002).”
Protoclusters associated with z > 2 radio galaxies - I. Characteristics of high redshift protoclusters (2006, background): “The relatively smallFWHM of the Lyα line (FWHM = 700 km s−1) suggests that this object is a type-II AGN (e.g., Norman et al., 2002).”
DEEP EXTRAGALACTIC X-RAY SURVEYS (2005, background): “A number of X-ray obscured quasars have been found in deep surveys (e.g., Norman et al. 2002; Stern et al. 2002b; Barger et al. 2003a; Szokoly et al. 2004).”
Red and Reddened Quasars in the Sloan Digital Sky Survey (2003, background): “The Fraction ofMissing Quasars We have not formally addressed the question of what fraction of quasars are missed by normal optically selected samples of quasars because of reddening or because they would be classified as ‘‘ type 2 ’’ (narrow line only) quasars (e.g., Norman et al. 2002).”