The XMM-Newton view of PG quasars - I. X-ray continuum and absorption

By E. Piconcelli, E. Jiménez-Bailón, M. Guainazzi, N. Schartel, P. Rodríguez-Pascual, M. Santos-Lleo. 2004

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We present results of a systematic analysis of the XMM-Newton spectra of 40 quasars (QSOs) (z ≤ 1.72) from the Palomar-Green (PG) Bright Quasar Survey sample (MB < −23). The sample includes 35 radio-quiet quasars (RQQs) and 5 radio-loud quasars (RLQs). The analysis of the spectra above 2 keV reveals that the hard X-ray continuum emission can be modeled with a power law component with � Γ2−12 keV� = 1.89 ± 0.11 and � Γ2−12 keV� = 1.63 +0.02 −0.01 for the RQQs and RLQs, respectively. Below 2 keV, a strong, broad excess is present in most QSO spectra. This feature has been fitted with four different models assuming several physical scenarios. All tested models (blackbody, multicolor blackbody, bremsstrahlung and power law) satisfactorily fitted the majority of the spectra. However, none of them is able to provide an adequate parameterization for the soft excess emission in all QSOs, indicating the absence of a universal shape for this spectral feature. An additional cold absorption component was required only in three sources. On the other hand, as recently pointed out by Porquet et al. (2004) for a smaller sample of PG QSOs, warm absorber features are present in 50% of the QSO spectra in contrast with their rare occurrence (∼5−10%) in previous studies. The XMM-Newton view of optically selected bright QSOs therefore suggests that there are no significant differences in the X-ray spectral properties compared with those of the low-luminosity Seyfert 1 galaxies. Properties of the Fe Kα emission lines are presented in a companion paper.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6ab43b6e175822ca31a683b49d2b156c37b0a750

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Citations in the corpus

AGN wind scaling relations and the co-evolution of black holes and galaxies (2017, background): “In addition, AGN-driven winds from the accretion disk scale up to the dusty torus are now detected routinely both in the local and in the distant Universe, as blue-shifted absorption lines in the X-ray spectra of a substantial fraction of AGN (e.g. Piconcelli et al. 2005; Kaastra et al. 2014).”
Refining the fundamental plane of accreting black holes (2006, background): “These eff cts are usually explained by a relativistic jet component in the RLQ case (see e.g., Reeves & Turner 2000; Piconcelli et al. 2005).”
Piecing together the X-ray background : bolometric corrections for active galactic nuclei (2007, neutral): “…et al. (2003), [26] - McAlary et al. (1983), [27] - Gibson et al. (2005), [28] - Morales & Fabian (2002), [29] - Bonning et al. (2005), [30] - Piconcelli et al. (2005), [31] - Ueda et al. (2005), [32] - Surace et al. (2001), [33] - McLure & Dunlop (2001), [34] - Brocksopp et al. (2006), [35]…”
X-Ray Thermal Coronae of Galaxies in Hot Clusters: Ubiquity of Embedded Mini-Cooling Cores (2006, background): “Although the temperature range, 0.3 - 0.6 keV, is not too far from the typical values for the soft excess in AGN, the soft-to-hard flux ratio at the 0.5 - 2 keV band is much higher, 2.1 - 27 with a median of 4-5, compared with 0.06 - 3.0 with a median of 0.65 in Piconcelli et al. (2005).”
BAT AGN Spectroscopic Survey. V. X-Ray Properties of the Swift/BAT 70-month AGN Catalog (2017, background): “The presence of a soft excess had been found to be ubiquitous in optically-selected quasars (e.g., Piconcelli et al. 2005).”
The Hard X-Ray Spectrum as a Probe for Black Hole Growth in Radio-Quiet Active Galactic Nuclei (2008, methodology): “…unobscured RQ AGNs have confirmed the Brandt et al. (1997) Γ-FWHM(Hβ ) anticorrelation (e.g., Leighly 1999; Reeves & Turner 2000; Porquet et al. 2004; Piconcelli et al. 2005; Brocksopp et al. 2006), and others have found significant correlations betweenΓ and L/LEdd (e.g., Lu & Yu 1999; Porquet et…”
The multi-phase winds of Markarian 231: from the hot, nuclear, ultra-fast wind to the galaxy-scale, molecular outflow (2015, background): “In X-rays mildly ionized warm absorbers with velocities of ∼500−1000 km s −1 are observed in more than half of AGN (Piconcelli et al. 2005; Blustin et al. 2005; McKernan et al. 2007).”
CAIXA: a catalogue of AGN in the XMM-Newton archive - II. Multiwavelength correlations (2009, result): “2), confirming previous claims (e.g. Piconcelli et al. 2005).”
An X-ray view of 82 LINERs with Chandra and XMM-Newton data (2009, background): “Nearby examples of both Seyfert 2 (Maiolino et al., 1998; Risaliti et al., 1999; Page et al., 2003; Cappi et al., 2006; Panessa et al., 2006), and Seyfert 1 (Nandra et al., 2007) or PG-QSOs (Piconcelli et al., 2005; Jimenez-Bailon et al., 2005) have been studied.”
The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era (2006, background): “On the one hand, observations of bright nearby Seyferts and QSOs reveal a soft excess below 1–2 keV (Perola et al. 2002; Porquet et al. 2004; Piconcelli et al. 2005) in many objects, which has been interpreted either as the exponential tail of the thermal emission from the accretion disk (Czerny &…”
The first ultraviolet quasar-stacked spectrum at z ≃ 2.4 from WFC3 (2015, background): “The photon index has been fixed to 1.9, which is usually observed in quasars (e.g. Piconcelli et al. 2005).”
The Sloan Digital Sky Survey View of the Palomar-Green Bright Quasar Survey (2005, background): “In particular, it has been recently suggested that XMM-Newton spectra of PG quasars reveals a near universality of the so-called soft X-ray excess below 2 keV (Porquet et al. 2004; Piconcelli et al. 2005).”
The Hard X-Ray Spectral Slope as an Accretion Rate Indicator in Radio-quiet Active Galactic Nuclei (2006, neutral): “…(z 0.5) type 1 radio-quiet quasars (RQQs) have consistently shown thatG ∼ 2.0 0.5, and some of those studies confirmed the Brandt et al. (1997) G–FWHM(Hb) relationship (e.g., Leighly 1999; Reeves & Turner 2000; Porquet et al. 2004; Piconcelli et al. 2005, hereafter P05; Brocksopp et al. 2006).”
Massive molecular outflows and evidence for AGN feedback from CO observations (2013, neutral): “…Maiolino et al. (1997); 12 – Wiklind et al. (1995); 13 – Tsai et al. (2009); references for LAGN: a – Nardini et al. (2009); b – Nardini et al. (2010); c – Veilleux et al. (2009); d – Piconcelli et al. (2005); e – Risaliti (priv. comm.); f – Moustakas & Kennicutt (2006); g – Croston et al. (2008);…”
The X-ray nuclei of intermediate-redshift radio sources (2006, methodology): “The parameters of the double-power-law model are very similar to those fitted by Piconcelli et al. (2005) to the same X-ray data.”
The Compact, Conical, Accretion-Disk Warm Absorber of the Seyfert 1 Galaxy NGC 4051 and Its Implications for IGM-Galaxy Feedback Processes (2007, background): “Ionized absorption outflows (Warm Absorbers: WA) have been observed in the Ultra- violet (UV) and X-ray spectra of >∼ 50 % of Seyfert 1s (e.g. Crenshaw, Kraemer & George 2003) and quasars (Piconcelli et al. 2005), with line of sight velocities of the order of a few hundreds to ∼ 2000 km s−1.”
Resolving the mid-infrared cores of local Seyferts (2009, background): “This is because the typical observed range ofΓ is≈ 1.5–2.3 (e.g. Nandra & Pounds 1994; Mateos et al. 2005; Piconcelli et al. 2005), and the difference between a constantΓ = 1.9 and the extremes of the stated range results in only a small difference of ∆αIX=±0.04 (assuming no change inLX).”
The X-Ray Properties of the Most Luminous Quasars from the Sloan Digital Sky Survey (2007, methodology): “The fluxes have been calculated usingPIMMS, assuming a power-law model withΓ = 2.0, which is a typical photon index for luminous AGNs (e.g., Reeves & Turner 2000; Page et al. 2005; Piconcelli et al. 2005; Shemmer et al. 2005a; Vignali et al. 2005; see§5.1 for direct justification).”