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The Differences in the SEDs of Type 1 and Type 2 AGNs: Contributions from starbursts Xue-Bing Wu Collaborator: Ran Wang (Astronomy Department, Peking University) See also poster of Ran Wang
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Content Introduction AGN Data & SEDs Bolometric luminosity and nuclear AGN power Discussions & summary
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1. Introduction Orientation-dependent unification scheme of AGN (Antonucci 1993); Supported by the polarized spectral observations of NGC 1068 Only about half of Sy2s showing polarized broad emission lines (HBLRs). Are HBLRs physically different from Non-HBLRs? Observational differences of two types of Sy2s IRAS flux ratio (f 25 / f 60 ) (Heisler et al. 1997) Narrow line flux ratio (f [OIII] / f H ) (Tran 2003) Luminosity (Tran 2003) X-ray spectra (Deluit 2004)
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BLR could disappear if the luminosity is lower The effective photo-ionization region is too close to the central BH for low-L narrow line AGNs (Laor 2003) Non-HBLRs have lower accretion rate (<1E-3, in Eddington unit) than HBLRs (Nicastro, Martocchia & Matt 2003)
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AGN SEDs RL & RQ Quasars (Sanders et al. 1989; Elvis et al. 1994) Seyfert 1s & 2s (Mas-Hesse et al. 1995) Seyfert 2s, comparisons with SEDs of starburst galaxies, LINERs and normal galaxies (Schmitt 1997) Purpose of our work SEDs of HBLRs & Non-HBLRs True AGN power of Sy2s
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2. AGN Data & SEDs Sy 2s: Schmitt et al. (1997); Gu & Huang (2002); Tran (2003) HBLRs & Non-HBLRs Sy 1s: Woo & Urry (2002) Intermediate type Sy 1s (Sy 1.8, 1.9) & NLS1s excluded Sample: 16 Sy 1s, 12 HBLRs, 11 Non-HBLRs,
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X-ray: ASCA, BeppoSAX, EXOSAT; corrected for absorption UV: IUE Optical: ground-based observations; NED IR: NED(2MASS,IRAS,ISO); corrected for Galactic extinction in near-infrared Radio: NED Choose the data with similar apertures whenever possible
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AGN sample Sample: 16 Sy 1s, 12 HBLRs, 11 Non-HBLRs
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Individual SEDs
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Average SEDs for S1, HBLRs & Non- HBLRs
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Differences in SEDs: Non-HBLRs seem to be much weaker in hard X- ray band S1s and HBLRs show different features in IR & optical bands; HBLRs are relatively stronger in IR Non-HBLRs show a steeper increase towards the far IR band than S1 and HBLRs; Strong far IR emission seems to dominate the bolometric luminosity of Non-HBLRs
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3. Bolometric luminosity and nuclear AGN power Column density (N H ) S1s are all compton thin; HBLRs & Non-HBLRs consist of both Compton thin and thick sources
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Bolometric luminosity The total emission of HBLRs & Non-HBLRs are similar, but their SEDs are different.
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2-10keV hard X-ray luminosity Compton thin HBLRs are similar to S1s, but compton thin Non- HBLRs are different and have lower X-ray energy,
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Hard X-ray luminosity & bolometric luminosity
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A relation between hard-X-ray luminosity & nuclear bolometric luminosity
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Eddington luminosity (BH mass calculated from the M- relation) No significant difference for different types of Sys, consistent with the suggestion that BH mass distributions are similar in whole Sy classes (Wu & Han 2001)
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4. Discussions & summary Intrinsic differences may exist in different types of AGNs; Different physics processes dominate the energy production in different bands Factors affect the far IR emission Nuclear emission UV emission from massive stars (heating the dusts and re-radiating in far IR) Circumnuclear star formation/starburst activities in whole Seyfert classes (Wilson 1991; Mouri & Taniguchi 1992, 2004; Hecman et al. 1997)
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SEDs of Seyferts and starburst galaxies
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SEDs of Seyferts, NLS1s & Quasars
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Differences in accretion rate (Eddington ratio) BLR may not exist at lower accretion rate!
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Summary Average SEDs of HBLRs & Non-HBLRs are presented; Though with a stronger IR bump, HBLRs display many similar feature with S1s Bolometric luminosity of Non-HBLRs is dominated by far IR emission, while their hard X-ray emission is weaker than S1 and HBLRs Bolometric luminosity of Non-HBLRs is affected significantly by star formation activities and may not indicate the true AGN power Dimensionless accretion rates of Non-HBLRs is significantly smaller than that of HBLRs and S1s BLR may not exist at lower accretion rate
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