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Starburst in Seyfert 2 Nuclei. Qiusheng Gu (NJU, China) Jorge Melnick (ESO, Chile) R. Cid Fernandes (UFSC, Brazil) Daniel Kunth (IAP, France) Elena Terlevich (INAOE, Mexico) Roberto Terlevich (INAOE, Mexico) Paper I: Joguet B., Kunth D., Melnick J., et al. 2001, A&A,
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Starburst in Seyfert 2 Nuclei Qiusheng Gu (NJU, China) Jorge Melnick (ESO, Chile) R. Cid Fernandes (UFSC, Brazil) Daniel Kunth (IAP, France) Elena Terlevich (INAOE, Mexico) Roberto Terlevich (INAOE, Mexico) Paper I: Joguet B., Kunth D., Melnick J., et al. 2001, A&A, 380, 19 Paper II: Cid Fernandes R., Gu Q., Melnick J., et al. 2004, MNRAS, 355, 273.
Starburst-AGN connection • Tight relation between black hole and bulge mass • Sy2s: ideal objects for studying starburst-AGN connection • ~50% Sy2s are detected with nuclear starburst
DSS (5’) UV (WFPC2,20”) NGC 4303 (1”=78pc) NGC 3351 (1”=42pc) Starburst in Seyfert 2 Galaxies
Example: NGC 5135 F606w F210m AGN! F606W+0.4-8keV 0.4-8keV
NGC 4303: STIS UV SPECTROSCOPY NGC 4303 PA 220 ultraviolet STIS F25QTZ (0.025”/pixel) Wavelength (Å) Luis Colina et al. (2002)
Removing Stellar Contribution • Cid Fernandes, Gu, Melnick, et al. 2004, MNRAS An Example: Stellar population synthesis for ESO103-G35
Measuring Accurate Fluxes [OIII]5007 [OII]3727 Hβ Hγ Hδ
Results: for a sample of Seyfert 2s 1、 the relation between stellar and gaseous extinction; 2、Luminosity vs. velocity dispersion; 3、the contribution from the starburst to ionizing photons; 4、the scatter of Faber-Jackson relation for Seyfert 2 galaxies
Conclusions 1、We measured the accurate fluxes of emission lines for a sample of 66 Seyfert 2 galaxies from the “pure” emission-line spectra. 2、Photoionization by young stars can provide a substantial fraction of ionizing photons for Seyfert 2 nuclei. 3、 We confirm the existence of Faber-Jackson relation for Seyfert 2 galaxies, and find the scatter is correlated with the AGN activity.