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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)

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Presentation on theme: "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)"— Presentation transcript:

1 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

2 Content Introduction AGN Data & SEDs Bolometric luminosity and nuclear AGN power Discussions & summary

3 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)

4 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)

5 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

6 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,

7 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

8 AGN sample Sample: 16 Sy 1s, 12 HBLRs, 11 Non-HBLRs

9 Individual SEDs

10 Average SEDs for S1, HBLRs & Non- HBLRs

11 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

12 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

13 Bolometric luminosity The total emission of HBLRs & Non-HBLRs are similar, but their SEDs are different.

14 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,

15 Hard X-ray luminosity & bolometric luminosity

16 A relation between hard-X-ray luminosity & nuclear bolometric luminosity

17 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)

18 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)

19 SEDs of Seyferts and starburst galaxies

20 SEDs of Seyferts, NLS1s & Quasars

21 Differences in accretion rate (Eddington ratio) BLR may not exist at lower accretion rate!

22 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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