The Differences in the SEDs of Type 1 and Type 2 AGNs: Contributions from starburstsXue-Bing Wu

Collaborator: Ran Wang(Astronomy Department,Peking University)

See also poster of Ran Wang

Content

Introduction AGN Data & SEDs Bolometric luminosity and nuclear AGN powe

r Discussions & summary

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 (f25 / f60 ) (Heisler et al. 1997)

Narrow line flux ratio (f [OIII] / f H) (Tran 2003) Luminosity (Tran 2003) X-ray spectra (Deluit 2004)

BLR could disappear if the luminosity is lower The effective photo-ionization region is too close t

o 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)

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 ga

laxies, LINERs and normal galaxies (Schmitt 1997)

Purpose of our work SEDs of HBLRs & Non-HBLRs True AGN power of Sy2s

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 exc

luded Sample: 16 Sy 1s, 12 HBLRs, 11 Non-HBLRs,

X-ray: ASCA, BeppoSAX, EXOSAT; corrected for absorption

UV: IUE Optical: ground-based observations; NED IR: NED(2MASS,IRAS,ISO); corrected for Galactic e

xtinction in near-infrared Radio: NED

Choose the data with similar apertures whenever possible

AGN sample

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

Individual SEDs

Average SEDs for S1, HBLRs & Non-HBLRs

Differences in SEDs: Non-HBLRs seem to be much weaker in hard X-ra

y band S1s and HBLRs show different features in IR & op

tical 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

3. Bolometric luminosity and nuclear AGN power Column density (NH)

S1s are all compton thin;

HBLRs & Non-HBLRs consist of both Compton thin and thick sources

Bolometric luminosity

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

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,

Hard X-ray luminosity & bolometric luminosity

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

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)

4. Discussions & summary Intrinsic differences may exist in different type

s 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 dust

s and re-radiating in far IR) Circumnuclear star formation/starburst activities i

n whole Seyfert classes (Wilson 1991; Mouri & Taniguchi 1992, 2004; Hecman et al. 1997)

SEDs of Seyferts and starburst galaxies

SEDs of Seyferts, NLS1s & Quasars

Differences in accretion rate (Eddington ratio)

BLR may not exist at lower accretion rate!

Summary Average SEDs of HBLRs & Non-HBLRs are prese

nted; 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