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An XMM-Newton view of Q2122-444: an AGN without Broad Line Region?

An XMM-Newton view of Q2122-444: an AGN without Broad Line Region?. Mario Gliozzi (GMU) L. Foschini (IASF Bo) R. Sambruna (GSFC) L. Kedziora-Chudczer (Sidney). * Type I and Type II AGN Unification Model HBLR vs non-HBLR

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An XMM-Newton view of Q2122-444: an AGN without Broad Line Region?

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  1. An XMM-Newton view of Q2122-444: an AGN without Broad Line Region? Mario Gliozzi (GMU) L. Foschini (IASF Bo) R. Sambruna (GSFC) L. Kedziora-Chudczer (Sidney) *Type I and Type II AGN Unification Model HBLR vs non-HBLR *X-ray advantage * “Naked” AGN * X-ray (XMM+Chandra) view of Q2122-444

  2. Q2130-431 Q2130-431 Broad permitted lines Strong & variable continuum Q2125-431 Q2125-431 Narrow forbidden & permitted lines Weak & constant continuum Optical View: Type I AGN: Type II AGN: [Fig. from Hawkins 2004]

  3. Differences ascribed to viewing angle: Type I Type II Unification Model AGN intrinsically the same: Basic Ingredients mass *Supermassive BH *Accretion disk + corona *BLR: high velocity, high density gas on pc scales *NLR; lower velocity, lower density gas on kpc scales *Torus: gaseous & molecular absorbing medium in equatorial plane embedding BH, ADC, BLR *Jets: relativistic ejection (10% AGN)

  4. Spectropolarimetry Measure of polarization of light as a function of wavelengths Instrumental in the development of Unification Model: Detection of broad permitted lines in polarized light in Sy2 NGC 1068 (Miller & Antonucci 1983) : * presence of hidden BLR (HBLR) * constraints on location and geometry of the absorber But exceptions exist: *Only 50% of Sy2 have HBLR (e.g. Tran 2001) based on 3-m (Lick) and 5-m (Palomar) telescopes * Result confirmed by Keck 10-m telescope (Moran et al. 2007)

  5. non-HBLR vs. HBLR Unified Model explains observations, not physical origin of ingredients Exceptions important not to disprove the model but gain insights into links among AGN ingredients Study of HBLR and non-HBLR based on Lradio L[O III] or IR colors: a) Intrinsically different: L(HBLR) > L(non-HBLR) (e.g. Moran et al. 1992; Tran 2001) b) Not different : biased results, affected by dilution effects from host galaxy (e.g. Lumsden et al. 2001; Lumsden & Alexander 2001)

  6. X-ray Advantage X-ray produced & reprocessed close to BH: Best diagnostics for central engine (Hard) X-rays less affected by absorption: Direct estimate of NH No diluting effects from host galaxy But not exhaustive: Need to complement information with other wavelengths

  7. X-ray view: HBLR vs. non-HBLR a) non-HBLR intrinsically different Existence of a threshold Lx=3 1042erg/s (Eddington ratio=10-3) : Below threshold: non-HBLR Above threshold: HBLR Sample: objects from Tran with archival Chandra, XMM, ASCA, or SAX data (Nicastro et al. 2003) Nicely fit theoretical model (Nicastro et al. 2000) b) non-HBLR more heavily absorbed Sample: 4 “best” candidates from Tran sample (no BL, high S/N, low optical extinction) Chandra observations 10 ks (Gosh et al. 2007) Limits of spectropolarimetry studies: * require very high S/N (limited nearby objects) * rely on existence of appropriately placed scattering region

  8. Naked AGN: Discovery Based on large scale optical monitoring program over 25 years from UK 1.2m Schmidt telescope in Australia. Initial sample: 1500 AGN candidates Intermediate sample: 129 Seyfert-like objects (high S/N, z<0.5) Final sample: 55 Seyfert 2 galaxies (Hawkins 2004) Selection based on spectral & temporal variability properties: *Spectrum ensures (apparent) lack of BLR *Variability ensures direct view of central engine (and jet?) 6 naked AGN (spectrally type II, but variable as type I) detected

  9. Seyfert 2 starburst Seyfert 1 Naked AGN: Optical Classification (Hawkins 2004) Type I AGN : FWHM > 1500 km/s, [OIII]/Hβ < 3, ∂B > 0.5 Type II AGN : FWHM < 1500 km/s, [OIII]/Hβ > 3, ∂B < 0.5 (∂B=Bmax-Bmin)

  10. Seyfert 2 starburst Seyfert 1 Naked AGN : FWHM < 1500 km/s, [OIII]/Hβ > 3, ∂B > 0.5 Naked AGN: Optical Classification (Hawkins 2004) Type I AGN : FWHM > 1500 km/s, [OIII]/Hβ < 3, ∂B > 0.5 Type II AGN : FWHM < 1500 km/s, [OIII]/Hβ > 3, ∂B < 0.5 Note : NLS1 ruled out by [OIII]/Hβ < 3, but not blazars

  11. X-ray Observations of Q2122-444 Q2122-444: z=0.311,Hβ FWHM = 350 km/s,[OIII]/Hβ =6, ∂B = 0.9 Goal: investigate nature of source *Constrain NH *Jet role? Chandra observations: Date: December 2005 Exposure: 4ks (part of snapshot survey) Instrument: ACIS-S (Gliozzi et al. 2007) XMM observations: Date: November 2007 Exposure: 40ks (pointed observation) Instruments: EPIC pn, MOS1, MOS2; OM

  12. X-ray Imaging of Q2122-444 * Source easily detected: bright X-ray source * Point-like appearance (consistent with ACIS PSF) * No nearby sources within 1’ Unusual optical properties notdue to source confusion. Only 1 source in XMM extraction region.

  13. X-ray Imaging of Q2122-444 * Source easily detected: bright X-ray source * Point-like appearance (consistent with ACIS PSF) * No nearby sources within 1’ Unusual optical properties notdue to source confusion. Only 1 source in XMM extraction region.

  14. Chandra: XMM-Newton: X-ray Spectrum of Q2122-444 Spectra well fitted with simple absorbed PL. Low NH suggests direct view of central engine.

  15. Short timescales: No significant flux nor spectral variability Long timescales flux variability: L0.5-8keV(Chandra) = 3.2 1043 erg/s L0.5-8keV(XMM) = 1.4 1043 erg/s Long timescales spectral variability HR(Chandra) = -0.57(13) HR(XMM) = -0.25(3) where HR=(h-s)/(h+s) The luminosity decreases by a factor of 2, and the spectrum hardens. X-ray Variability of Q2122-444

  16. Broadband Properties of Q2122-444 Optical UV from the OM: * mB=21.0(4), mU=20.1(2), mUVW1=20.0(2) * Extinction fully consistent with NH * Broadband spectral index αOX=1.30(6) Radio from ATCA: (2.7 hr observations at 4.8 and 8.6 GHz) * Source not detected * Low radio loudness: RO <5, RX <10-4

  17. Q2122-444: Summary * The source is bright: Lx > 1043 erg/s (Eddington ratio = 10-2) * X-ray spectral properties (Г and NH) typical of Seyfert 1 galaxies * X-ray spectral variability properties (soft when bright) typical of Seyfert 1 galaxies * Broadband properties (αOX and AV) confirm this scenario * Low radio upper-limit rules out important contribution from putative jet

  18. Q2122-444: Conclusions Q2122-444 apparently lacks BLR but brighter than non-HBLR Important to expand this work (enlarge sample, E band): 1) Representative of a large AGN class: -high detection rate from original sample -sizable fraction of narrow-lined AGN at Lx~1043 erg/s (Steffen et al. 2003) 2) May help shedding light on the origin of BLR and link with absorbing medium (e.g. clumpy torus modelNenkova et al. 2002)

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