The [ITAL][CLC]z[/CLC][/ITAL] = 5.8 Quasar [CLC]SDSSp[/CLC] J1044−0125: A Peek at Quasar Evolution?

Mathur, S.

doi:10.1086/323307

Cited by 8 publications

(6 citation statements)

References 18 publications

(14 reference statements)

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“…As suggested by some authors (e.g., King 2003;King & Pounds 2003;Mathur 2001) the strong winds observed in some AGN are probably associated with large accretion rates. In particular, quasars characterized by the strongest outflows (in terms of mass outflow rate) may be accreting at or above the Eddington rate.…”

Section: Discussionmentioning

confidence: 65%

Extreme gas properties in the most distant quasars

Maiolino

Oliva

Ghinassi

et al. 2004

A&A

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Abstract. We present near-IR, low resolution spectra of eight of the most distant quasars known, with redshifts in the range 4.9 < z < 6.4. Half of these quasars are characterized by deep, broad and blueshifted absorption features associated with both high and low ionization species (CIV, SiIV, AlIII, MgII), i.e. they belong to the class of Broad Absorption Line (BAL) quasars, which are associated with powerful outflows of dense gas. Although the sample is small, the large fraction of BAL quasars, the depth and ionization state of the absorption features suggest that these most distant quasars are surrounded by a much larger amount of dense gas than lower redshift (z < 4) quasars. The possible interpretation in terms of extremely high accretion rates and the association with the early formation of quasars and of their host galaxies is discussed. The absorption properties of the dust, associated with the gas along the line of sight, appear different with respect to lower redshift quasars, possibly indicating different dust physics at these highest redshifts.

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Section: Discussionmentioning

confidence: 65%

Extreme gas properties in the most distant quasars

Maiolino

Oliva

Ghinassi

et al. 2004

A&A

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“…While such steep X-ray spectra have been observed in a number of Narrow-Line Seyfert 1 galaxies (e.g. Boller et al (1996); Grupe et al (1998); Grupe et al (2001)), only one other high redshift quasar (SDSS J1044-0125 at z=5.8) with possible steep X-ray spectrum is known (Mathur (2001); note that the 0.1-0.4 keV range in the observed soft band corresponds to rest frame 0.53-2.1 keV in the rest frame of BR0351-1034, similar to the ROSAT band). It is commonly believed that the steep soft X-ray spectra in NLS1s are the result of close to Eddington accretion (e.g.…”

Section: The Radio-quiet Quasar Br0351-1034mentioning

confidence: 98%

XMM-NewtonObservations of Two High-Redshift Quasars: RX J1028-0844 and BR 0351-1034

et al. 2004

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We report the results of XMM-Newton observations of two high-redshift quasars, one radio-loud, RX J1028.6À0844 (z ¼ 4:276) and one radio-quiet, BR 0351À1034 (z ¼ 4:351). We find that the evidence for strong excess absorption toward RX J1028À0844 is marginal at best, contrary to previous claims. The superior sensitivity and broader, softer energy range of XMM-Newton (0.2-10 keV) allows better determination of spectral parameters than much deeper ASCA observations (0.8-7 keV). Our XMM-Newton observations call into question several other ASCA results of strong absorption toward high-redshift radio-loud quasars. RX J1028.6À0844 occupies the same parameter space in broadband spectral properties as the low-redshift BL Lac objects, showing no obvious evolution with redshift. The radio-quiet quasar BR 0351À1024 became fainter between ROSAT and XMM observations by a factor of at least 5, but with the present data we cannot determine whether there is an associated spectral change. These observations do not support previous claims of weaker X-ray emission from high-redshift, radio-quiet quasars. The soft X-ray spectral slope required to reconstruct the ROSAT PSPC hardness ratio of BR 0351À1034 is about X ¼ 3:5, the steepest X-ray slope ever observed in a high-redshift quasar and similar to that of low-redshift narrow-line Seyfert 1 galaxies.

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“…Recently, it has been proposed that NLS1s may be relatively young AGNs with a black hole still in a growing-up phase (e.g., Mathur 2000aMathur , 2000bMathur, Kuraszkiewicz, & Czerny 2001; see also Komossa & Mathur 2001;Mathur 2001). If NLS1s possess a smaller mass black hole than BLS1s while the luminosity is similar between NLS1s and BLS1s, a mass accretion rate for the same black hole mass is larger in NLS1s than in BLS1s.…”

Section: Introductionmentioning

confidence: 99%

Gas Metallicity of Narrow‐Line Regions in Narrow‐Line Seyfert 1 Galaxies and Broad‐Line Seyfert 1 Galaxies

Nagao

Murayama

Shioya

et al. 2002

ApJ

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We investigate gas metallicity of narrow-line regions in narrow-line Seyfert 1 galaxies (NLS1s) and broad-line ones (BLS1s) in order to examine whether or not there is a difference in the gas metallicity between the two populations of Seyfert 1 galaxies. We apply two methods to study this issue. One is to use the emission-line flux ratio of [N ii]λ6583/Hα narrow in combination with some other optical emission-line flux ratios. This method, which has been often applied to Seyfert 2 galaxies, suggests that the gas metallicity of narrow-line regions is indistinguishable or possibly higher in BLS1s than in NLS1s. On the contrary, the other method in which only forbidden emission-line fluxes are used results in that NLS1s tend to possess metal-richer gas in the narrow-line regions than BLS1s. We point out that this inconsistency may be owing to the contamination of the broad component of permitted lines into the narrow component of ones in the first method. Since the results derived by using only forbidden emission-line fluxes do not suffer from any uncertainty of the fitting function for the broad component of Balmer lines, the results from this method are more reliable than those derived by using permitted lines. We thus conclude that the gas metallicity of narrow-line regions tends to be higher in NLS1s than in BLS1s.

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The [ITAL][CLC]z[/CLC][/ITAL] = 5.8 Quasar [CLC]SDSSp[/CLC] J1044−0125: A Peek at Quasar Evolution?

Cited by 8 publications

References 18 publications

Extreme gas properties in the most distant quasars

Extreme gas properties in the most distant quasars

XMM-NewtonObservations of Two High-Redshift Quasars: RX J1028-0844 and BR 0351-1034

Gas Metallicity of Narrow‐Line Regions in Narrow‐Line Seyfert 1 Galaxies and Broad‐Line Seyfert 1 Galaxies

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